Flaps Flashcards

Question

A 9-year-old girl is evaluated for scar revision after sustaining a laceration of the left cheek that was repaired in the emergency department 2 years ago. Examination shows a 4 × 0.7-cm scar that is pale, flat, and wide in appearance. It has an oblique orientation between the oral commissure and zygomatic arch. W-plasty is considered. Which of the following is the most likely outcome of the W-plasty when compared with linear closure in this patient? A) Decreased initial wound tension B) Decreased procedural time C) Increased contracture of the wound D) Increased removal of healthy tissue

Answer 1

The correct response is Option D. The W-plasty was first described by Borges in 1953. The repair involves a regular pattern of interdigitating triangular advancement flaps. This repair allows for the scar to have an accordion-like effect secondary to the broken line configuration. The W-plasty and geometric broken line closure (GBLC) techniques are commonly used for scar revisions and are best indicated for scars that cross the relaxed skin tension lines (RSTL) to redirect portions of the scar. Because of the flexibility these scars have, they are also indicated over convex or concave surfaces. Compared with linear closure, the W-plasty will have decreased contracture of the wound because of the interrupted orientation of the scar. Even though a portion of the final closure will go against the RSTLs, W-plasties can be designed to orient a significant portion along the RSTLs. Because of the many triangular flaps made and repaired, it takes significantly longer to perform a W-plasty repair. The main disadvantage of the W-plasty and GBLC procedures is the need to remove a significant amount of healthy tissue on either side of the scar to be revised, which can lead to increased wound tension and the need for significant undermining.

Answer 2

The correct response is Option D. The initial 24-hour period is critical to flap viability. In cases of compromised arterial inflow, steps that can be taken to improve arterial inflow are of primary concern. Ensuring adequate postoperative fluid resuscitation is paramount. This ensures adequate cardiac output and optimizes tissue perfusion. Medicinal leeches are indicated for venous congestion and would have questionable value in an ischemic setting. Although hyperbaric oxygen therapy and elevation may both have beneficial effects in this setting, they are less appropriate than fluid resuscitation. Some clinicians will use 2% nitroglycerin ointment to ischemic areas every four to six hours or silver sulfadiazine cream twice daily. Either of these techniques is believed to be useful in reducing the risk and extent of full-thickness skin loss but would probably not be as important as ensuring adequate hydration.

Answer 3

The correct response is Option D. Although all of these vessels supply flaps in the region of the lower abdominal wall, groin, and thigh, the superficial circumflex iliac artery (SCIA) is the dominant pedicle for free or pedicled, fasciocutaneous groin flaps. The long axis of the flap is centered over a line parallel and 3 cm inferior to the inguinal ligament, with a maximum reliable width of 10 cm. The flap is harvested from lateral to medial, beginning caudad to the posterior iliac spine and extending across the sartorius muscle to femoral vessels. To improve the reliability of the flap, Scarpa's fascia should be incorporated with the flap laterally, and dissection must continue below the sartorius fascia, as the deep circumflex iliac artery (DCIA) courses between the deep investing fascia of the sartorius and Scarpa's fascia. The base of the flap can be tubed to improve wound care and allow for closure of most of the donor site.

Answer 4

The correct response is Option D. Paraspinous muscle flaps are considered the "workhorse" of spinal reconstruction and are useful for the coverage of exposed hardware and the obliteration of dead space. The paraspinal muscles are classified as Type IV flaps with multiple segmental pedicles. The dominant pedicle of the paraspinous muscle flap consists of segmental perforating vessels arising from the posterior intercostal vessels. The minor pedicle includes lateral row perforators arising from the posterior intercostal arteries. REFERENCES: 1. Inglesby DC, Young ZT, Alshareef M, et al. Paraspinous muscle flaps for the treatment of complex spinal wounds. Spine. 2020;45(9);599-604. doi: 10.1097/BRS.0000000000003341 2. Zenn MR, Jones G, eds. Reconstructive surgery: anatomy technique and clinical applications. Quality Medical Publishing. St. Louis, Missouri; 2012: 758-776.

Answer 5

The correct response is Option E. In the jumping man or five flap plasty, the central flap is advanced through a Y to V method where the tip of the V is advanced into an incision made in the opposing tissue. There are different modifications to this technique for local flap lengthening of flexion contractures. Traditionally, the lateral limbs are designed with 60-degree angles to the central limb and the opposing limbs are designed more obtusely to prevent ischemia at the base. This type of reconstruction requires laxity of the surrounding skin and is therefore most often employed in places like the medial canthus, web spaces of the feet and hands, or the axilla. A V-Y advancement is commonly used in pressure ulcer repair where the base of the V is advanced into the defect to create a Y. This is the opposite of what one is trying to achieve in a jumping man plasty. Transpositions of 75, 60, and 45 degrees are all different variations of z-plasties and are utilized in this local rearrangement, but the central flap is advanced, not transposed/rotated.

Answer 6

The correct response is Option D. The benefit of perforator flaps over traditional musculocutaneous flaps is the ability to preserve muscle at the donor site. Depending on perforator anatomy, it can either traverse between surrounding myofascial units requiring no muscle sacrifice, or alternatively pass through the muscle substance requiring division of a small amount of muscle to liberate the flap. The anterolateral thigh (ALT) or deep inferior epigastric artery perforator (DIEP) flaps have variable perforator anatomy containing either septal or muscular perforators, or both within the same flap. The profunda and medial sural artery perforator flaps have vessels that pierce the adductor magnus and gastrocnemius muscles, respectively. Of the options listed, only the parascapular flap consistently has a septal perforator located between the teres major, teres minor, and the triceps. Reference(s) 1. Zenn and Jones. Reconstructive Surgery: Anatomy, Technique and Clinical Applications. 1st ed. Boca Raton, Florida: CRC Press; 2012:150. 2. Wei and Mardini. Flaps and Reconstructive Surgery. 1st ed. Philadelphia, PA: Elsevier Health Sciences; 2009: 326.

Answer 7

The correct response is Option E. When harvesting a reverse island flap such as the reverse radial forearm flap, the surgeon should always attempt to preserve an outflow vein, which will be necessary for drainage of the flap if the reverse flow venous system does not function adequately. Most patients exhibit only mild venous congestion, and leeches can be applied to drain the flap sufficiently and thus preserve it. However, any patient who has immediate onset of marked venous congestion in which the cause is not obvious (ie, kinking of the pedicle or hematoma under the flap) should undergo immediate anastomosis of an outflow vein to decompress the flap. Conservative measures such as increasing the temperature of the hand, elevating the extremity, or infusing heparin intravenously will ultimately fail in a patient with marked venous congestion requiring immediate operative treatment.

Answer 8

The correct response is option E. The most appropriate procedure to close this defect is a lateral calcaneal flap, which has an axial pattern based on the lateral calcaneal artery, a terminal branch of the peroneal artery. This flap is very reliable, even in older patients, and lateral calcaneal artery patency and flow can be determined by preoperative Doppler examination. The donor site is usually skin grafted. (See photographs below.) Other acceptable options include reverse sural flap and free tissue transfer. Bilateral V-to-Y advancement would be difficult in this patient because there is edema and inflammation associated with a chronic wound. The dorsalis pedis fasciocutaneous flap would reach this defect but has significant donor site morbidity and should be reserved for situations in which other options are not available. The flexor digiti minimi muscle flap is lateral on the foot but is not able to reach the lateral ankle. The extensor digitorum brevis muscle flap has a large arc of rotation but requires sacrifice of the dorsalis pedis artery.

Answer 9

The correct response is Option D. The rectus femoris muscle is the most superficial and central of the quadriceps extensor muscle group. It is a bipennate muscle that extends from the ilium to the patella and is surrounded by the vastus lateralis and vastus medialis muscles. The rectus femoris acts as an extensor of the knee, specifically powering the terminal 15 to 20 degrees of knee extension. It is also a powerful flexor of the hip. Recent studies have shown that the use of this muscle is effective for groin reconstruction. Mild, isolated deficits are observed although there is no clinical significance of this deficit.

Answer 10

The correct response is Option D. This patient has an open wound in the distal third of the tibia closed with a propeller flap based on a perforator from the posterior tibial artery. The most common complications associated with this type of reconstruction are venous congestion and partial flap loss. If congestion is encountered during flap elevation, it is essential to dissect the perforator all the way back to the named source vessel to release all fascial attachments and any areas of potential constriction or tethering. This would be the first strategy to improve venous outflow during flap dissection. The venae comitantes accompanying the perforator are very thin-walled and susceptible to kinking, especially when flap inset requires a 180-degree rotation. Propeller flaps are island fasciocutaneous flaps based on a single dissected perforator. They are termed “freestyle” because the design of the flap is determined intraoperatively based on the dissection of the perforator, which has variable anatomy. Ideal perforators are greater than 0.5 mm in diameter and pulsatile. Perforator flaps of the lower extremity should be designed longitudinally based on directional blood flow. Most published series report greater than 90% flap survival with an 8 to 10% rate of complications. If tension or kinking still exists after proximal perforator dissection, microsurgical venous supercharging would be the next course of action, if possible. De-rotating the flap and placing it back into the donor site as a delay procedure can be used as a last resort; however, vascular delay is traditionally used to augment the arterial inflow of a flap by allowing the choke vessels to open and organize the flow in an axial fashion. The flap remains susceptible to venous congestion when it is rotated for inset after the delay as well. A small amount of decreased venous drainage is expected with most perforator flaps; however, it is generally mild, not progressive, and confined to the distal tip of the flap. This venous insufficiency can be observed and will generally resolve in the early postoperative period. In this case, the congestion was noted early during flap dissection along the full length of the flap. For severe early venous congestion, observation is not appropriate. Leech therapy is often used to relieve venous congestion of flaps and replanted parts postoperatively if additional venous outflow cannot be established surgically. Abandoning further surgical efforts to plan for leeching would not be advised as an initial course of action. The traditional reconstructive algorithm for reconstruction of distal one-third defects recommends free tissue transfer. The advent of perforator propeller flaps allows for reconstruction with available like tissue that does not involve microsurgery. Free flap reconstruction would generally be the plan following complete flap loss, but it would not be the next step in management of venous congestion. Acute venous insufficiency should not be managed with nitropaste therapy.

Answer 11

Correct answer is option B. Flaps require preservation of the defined arterial and venous supply. Regional flaps can be based distally or proximally. The lateral arm flap was initially described by Song and popularized by Matloub, et al. and Katsaros, et al. This flap has considerable application in reconstruction of the upper extremity. It can be harvested from the same extremity; it has thin, pliable skin; and it can be innervated. The lateral arm flap can also include a segment of vascularized humerus or a segment of vascularized triceps tendon. The flap can also be segmentally contoured for hand defects. The lateral arm free flap is based on the posterior radial collateral artery, which is a branch of the profunda brachial artery. A reversed pedicled lateral arm flap can also be performed. This reverse flap is based on the radial recurrent artery. The superior ulnar collateral artery is the dominant pedicle of the medial arm flap. The medial arm flap is also useful for upper extremity coverage, but there are significant variations in the superior ulnar collateral artery which makes this flap a less-than-optimal choice for microvascular surgical reconstruction. The posterior interosseous artery is the dominant blood supply of the posterior interosseous artery flap. The posterior interosseous artery flap is also used for reconstruction of the hand because it has thin, pliable skin. As a pedicle flap, it can cover the wrist and extend to the first web space. Use of the posterior interosseous flap can compromise motor nerves to the extensor carpi ulnaris or extensor digiti quinti.

Answer 12

The correct response is Option A. The latissimus dorsi flap would allow for the mobilization of sufficient skin and muscle to close the defect in the patient described. The latissimus dorsi muscle is a Mathes-Nahai Type V flap, with the main blood supply from the thoracodorsal artery and vein, and secondary segmental pedicles from the posterior intercostal and lumbar perforators. The latissimus dorsi insertion onto the humerus can be divided to provide further mobilization of the flap. To close the defect, the flap can be used as a €œturnover flap, € with its blood supply based medially on the secondary pedicles. It can also be transposed and advanced on its main blood supply. If needed, interposition vein grafts can be used to extend the vascular pedicle. The flap has a very well-defined anatomy with few anatomical variations, and its harvest is fairly straightforward. It has found tremendous use in reconstructing defects of the scalp, lower extremity, breast, and chest wall. A free rectus abdominis muscle flap could be performed, but recipient vessels in this area are not readily available. There have been reports of utilizing posterior intercostal perforators as recipient vessels for microvascular anastomosis, but this is an option best reserved as a last resort. Split-thickness skin grafting over a previously irradiated wound bed with exposed bone is not likely to heal. A trapezius muscle flap will not reach the level of T10. Wide undermining is a poor choice because this would lead to further devascularization of previously irradiated skin. Reclosure of the skin primarily is likely to occur under significant tension and would be prone to further necrosis and wound breakdown.

Answer 13

The correct response is Option A. The anterior branch of the obturator nerve provides motor innervation to the gracilis free muscle flap. This nerve branch courses between the adductor longus and adductor brevis tendons to innervate the gracilis muscle. The femoral nerve innervates the rectus femoris muscle at the level of the thigh, while the inferior branch of the superior gluteal nerve supplies motor innervation to the tensor fascia lata. The medial femoral cutaneous nerve, which is a branch of the femoral nerve, supplies sensory innervation to the medial thigh flap. The median sural nerve is found below the knee and courses parallel to the lesser saphenous vein.

Answer 14

The correct response is Option A. The deep circumflex iliac artery (DCIA) arises from the lateral aspect of the external iliac artery. From its takeoff point, it travels toward the anterior superior iliac spine (ASIS) between the transversalis fascia and transversus abdominis muscle. Just medial to the ASIS, it gives off an ascending branch which supplies the internal oblique muscle. Lateral to the ascending branch, the DCIA courses through the transversalis fascia along the inner lip of the iliac crest, where it lies in the line of fusion between the iliacus and transversalis fascia, and supplies the iliac crest bone. The deep inferior epigastric vessels supply transverse rectus abdominis myocutaneous (TRAM) and deep inferior epigastric artery perforator (DIEP) flaps. The superficial circumflex iliac vessels supply the groin flap. The superficial inferior epigastric vessels supply the superficial inferior epigastric artery (SIEA) flap, which comprises the skin and subcutaneous tissue only of the lower ipsilateral hemi-abdomen. The superficial femoral vessels supply flaps such as the sartorius muscle flap.

Answer 15

The correct response is Option C. The muscle flap best suited to reconstruct this defect is a medial head of gastrocnemius muscle rotation flap. Its dominant pedicle is the medial sural artery, which is a branch of the popliteal artery. The ascending branch of the medial circumflex artery is the dominant pedicle to the gracilis flap, whereas the minor pedicles are perforating branches of the distal superficial femoral artery. A proximally based gracilis flap would not have the arc of rotation to adequately cover the knee. A distally based flap would require a delay procedure and is not the best choice for this defect. The lateral sural artery is the dominant blood supply to the lateral head of the gastrocnemius, which is smaller, and, therefore, not as well suited for coverage of large patellar defects such as this one. The soleus is based off the proximal two branches of the posterior tibial artery, branches of the proximal popliteal, and branches of the peroneal artery. It is used for reconstruction of defects of the middle third of the lower extremity and does not have an arc of rotation sufficient enough to cover this defect.

Answer 16

The correct response is Option E. The tensor fascia lata, gastrocnemius, and vastus lateralis muscle flaps have a type I vascular pattern consisting of one dominant pedicle. These muscles can be used as rotation flaps for regional reconstruction or as free tissue for transfer. Type II muscle flaps have one dominant pedicle and several minor pedicles; examples include the abductor digiti minimi, gracilis, and soleus. In type III muscle flaps, such as the gluteus maximus, rectus abdominis, and serratus, there are two dominant vascular pedicles. The extensor hallucis longus, sartorius, and tibialis anterior muscle flaps have a type IV vascular pattern, with multiple segmental vascular pedicles entering along the course of the muscle belly. Type V muscle flaps, such as the latissimus dorsi and pectoralis major, have one dominant pedicle and secondary segmental pedicles, which provide a significant source of muscle circulation.

Answer 17

The correct response is Option B. The paraspinous muscle is supplied by the posterior intercostal artery; this is the same vessel that supplies the reverse latissimus dorsi flap. For a midline spinal defect, it is unlikely that these vessels are damaged; however, this is possible in large oncologic resections or traumatic injuries. The circumflex scapular artery supplies multiple flaps that are used for reconstruction, including the scapular and parascapular flaps. The transverse cervical artery supplies the trapezius muscle flap. The superior gluteal artery supplies the gluteus maximus muscle. The thoracodorsal artery is the main arterial supply of the latissimus muscle.

Answer 18

The correct response is Option D. Both the superior and inferior gluteal arteries are terminal branches of the internal iliac artery. They pass out of the pelvis above and below the piriformis muscle, supplying the upper and lower halves of the muscle, respectively. As the superior gluteal artery passes the greater sciatic foramen, it divides into superficial and deep branches. The deep branch travels between the gluteus medius muscle and the iliac bone. The superficial branch goes on to supply the gluteus muscle and the overlying skin territory. The superficial branch of the gluteal artery nourishes the fat and skin in the musculocutaneous flaps in this region. These perforating vessels can be separated from the underlying muscle and fascia and form the basis for the S-GAP flap, which allows maximal preservation of the donor site muscle and other underlying structures while creating a reliable skin €“soft-tissue flap. Two to three perforators are usually found arising from this vessel, with a pedicle length between 3 cm and 8 cm.

Answer 19

The correct response is Option A. The osteocutaneous radial forearm free flap (OCRFFF) is based on the radial artery, one of the major sources of blood to the hand. An abnormal Allen test is a sign of insufficient ulnar artery blood flow and would be a major contraindication to utilizing this flap. While the quantity of bone available for transfer from the radius is thought of as a limitation of this flap, many authors have reported safely harvesting up to 10 cm or more of bone length. The thickness of the bone is also a limitation and it is recommended that no more than one-third to one-half of the bone thickness be harvested to avoid an iatrogenic radial fracture, even when the remaining bone is prophylactically plated and/or bone grafted. Because of this, osseointegrated implants for dental restoration can rarely be performed. The bone component of the OCRFFF is well vascularized and associated with high rates of union and can tolerate osteotomies needed for anterior mandible restoration as well as be used for closing irradiated wounds. An advantage of this flap, in addition to providing a thin, pliable skin paddle, is that it has a long pedicle length that can often reach the inspilateral transverse cervical blood vessels or contralateral neck blood vessels without the need for interposition vein grafting.

Answer 20

The correct response is Option A. Arterialized venous free flaps are thin fasciocutaneous flaps that are useful in reconstructing defects of the hand. The main advantage of an arterialized venous flap is the ease of harvesting a thin flap without the need to sacrifice a major artery at the donor site. The design of venous flaps is very easy because of direct visualization of the venous plexus through the thin overlying skin. There is no limitation of the donor site because it is possible to find the venous network at any location of the body. They can be harvested as composite flaps, including nerve and tendon flaps. Despite many advantages, arterialized venous flaps are not commonly selected as the first choice for microsurgical reconstruction. Venous congestion is an expected part of the flap’s postoperative course, and this makes monitoring the flap especially difficult as compared with other conventional flaps. Signs of vascular insufficiency and characteristic edema and congestion of venous flaps are difficult to differentiate. In cases of venous congestion, flap viability can be monitored only by palpating the pulse or by laser Doppler probe analysis. Though venous congestion is common, the ultimate success rate of arterialized venous flaps is similar to that of conventional flaps, with total flap loss a rare occurrence.

Answer 21

The correct response is Option C. The Mathes and Nahai classification system is useful for predicting clinical applicability of various muscle and musculocutaneous flaps. With proper knowledge of the location and variation of muscle blood supply, the surgeon can safely determine the extent of muscle transposition during surgery. Five patterns of muscle circulation have been described. These patterns are based on the following relationships between the muscle and its vascular pedicle: The regional source of the vascular pedicle(s) entering the muscle Pedicle size Number of vascular pedicles Location of the pedicle in relation to muscle origin and insertion The angiographic patterns of intramuscular vessels The gluteal V-Y advancement flap used in the clinical scenario described is a Mathes/Nahai Type III flap. Type III muscle flaps demonstrate two large, independent vascular pedicles arising from separate regional arteries. Other Type III muscles include the rectus abdominis and serratus anterior. Angiographic studies have shown equal filling of the intramuscular vascular system with either pedicle injection. Type III muscle flaps can be based on either pedicle and can be split to preserve muscle function. In this particular ambulatory patient, only the superior half of the gluteal muscle (based on the superior gluteal artery) was used in order to preserve lower gluteal function. Type I muscles have a single dominant pedicle. Examples include the gastrocnemius, rectus femoris, and tensor fascia lata flaps. Type II muscle flaps demonstrate one or more large vascular pedicles near the muscle origin and several small pedicles entering the muscle belly distally. Commonly used muscle flaps in this group include the gracilis, soleus, and trapezius. The minor pedicles are typically divided to allow maximal muscle transposition. Division of the minor pedicles typically has little effect on muscle flap survival, but poorly planned musculocutaneous flaps may suffer distal skin ischemia if not planned appropriately. This vascular pattern is the most common pattern observed in anatomical studies of human cadaveric muscle. Type IV muscles demonstrate segmental vascularization along the entire length of the muscle. The sartorius and tibialis anterior muscles are the most clinically relevant muscles that display this type of pattern. The segmental nature of the blood supply severely limits the ability to transpose these muscles and therefore the utility is limited. Type V muscles display one dominant vascular pedicle near the muscle origin and multiple segmental pedicles near the muscle insertion. The latissimus and pectoralis major muscles demonstrate this vascular pattern. Angiographic studies demonstrate that the intramuscular vasculature can be supplied by either the dominant or segmental pedicles. As a result, the flaps can be elevated on either vascular system.

Answer 22

The correct response is Option A. The latissimus dorsi muscle free flap with split-thickness skin grafting can be used to reconstruct large scalp defects in a single stage, allowing the patient to proceed with radiation therapy after recovery from surgery. While temporary reconstruction with a split-thickness skin graft followed by definitive reconstruction with a rotation-advancement flap after tissue expansion is feasible for defects approaching 50% of the scalp surface area, this choice is inappropriate, as skin grafts usually have poor take on bare calvarium devoid of pericranium, particularly when treated with radiation. Radiated tissues are more difficult to expand, and their expansion is associated with a high rate of complications. Primary closure is usually only feasible in scalp defects less than 3 cm in diameter, even with galeal scoring to increase scalp flap length and reduce wound tension. Graft take can be improved by burring the bone down to the bleeding diploic space, but this technique results in unstable bone coverage, particularly in the setting of postoperative radiation.

Answer 23

The correct response is Option D. The Z-plasty is a fundamental plastic surgery technique that involves the elevation and interposition of two equal, interposed triangular skin flaps. This procedure can be used to improve soft-tissue contour via reorientation of skin, realign scars within the lines of minimal tension, and lengthen linear scar contractures. However, it is not performed for prevention of burn scar contractures.

Answer 24

The correct response is Option E. The boundaries of the triangular (or omotricipetal) space, in which the circumflex scapular artery is located, are comprised of the long head of the triceps muscle laterally, the teres major muscle inferiorly, and the teres minor muscle superiorly. The circumflex scapular artery is a branch of the subscapular artery and emerges from the triangular space to supply blood to the parascapular flap. The quadrangular space can be found immediately lateral to the triangular space. This space is defined by the surgical neck of the humerus, lateral head of the triceps muscle, teres major muscle, and teres minor muscle. The axillary nerve and posterior humeral circumflex artery pass through this space. The other muscles listed above can be identified in the region of the shoulder and trunk but do not define the triangular space.

Answer 25

The correct response is Option A. The submental flap is a myocutaneous flap that is useful in head and neck reconstruction. This flap provides a contour, color, and tissue texture that is suitably matched to the face. The flap is elevated below the level of the platysma muscle and includes the submental artery and vein, which are direct branches of the facial artery and vein. The flap can be transposed to cover defects in the lower and central thirds of the face and into the inferior aspect of the upper third of the face. The submental artery is a consistent branch of the facial artery and gives off one or two cutaneous perforators to the submental skin. The submental artery runs in relation to the anterior belly of the diagastric muscle. Of the choices listed, the facial artery is the most superior branch of the external carotid artery. The lingual artery provides the blood supply to the tongue, the superior thyroid and inferior thyroid arteries provide the blood supply to the thyroid gland, and the transverse cervical artery gives off a descending branch, which provides the blood supply to the trapezius muscle.

Answer 26

The correct response is Option B. The most appropriate muscle is the flexor hallucis longus. The fibular free flap is a workhorse flap for reconstruction of large segmental bone defects. The vascular supply of this flap comes from the peroneal artery. A large segment of bone can be harvested, consisting of the majority of the fibula with the exception of the proximal 6 cm at the fibular head and the distal 6 cm near the ankle joint. The fibular flap can be harvested with a skin paddle on the lateral aspect of the leg, based on perforators through the lateral intermuscular septum or via the muscle. The pedicle is located adjacent to the flexor hallucis longus muscle in the deep posterior compartment of the leg. Inclusion of a cuff of the flexor hallucis longus muscle can be performed to protect the pedicle and add bulk to the reconstruction if necessary. A composite flap of fibula and the entire flexor hallucis longus muscle has been described. The lateral portion of soleus muscle can also be included in the fibula free flap if desired. The extensor digitorum longus muscle is in the anterior compartment of the leg. The gastrocnemius muscle is in the posterior compartment of the leg and is more superficial. The peroneus longus muscle is in the lateral compartment of the leg. The tibialis posterior muscle is in the deep posterior compartment of the leg and is located along the interosseous membrane.

Answer 27

The correct response is Option D. Pedicled fascial flaps to the hand provide an excellent reconstructive option in cases of exposed tendon, joint, or bone where soft-tissue coverage is needed. They provide thin, broad, well-vascularized coverage and a gliding surface for tendons and joints. The pedicled reverse radial forearm flap is the most appropriate option for this defect. The cross-finger flap may be an option for a single digit, but not in the large zone-of-injury described. The groin flap, although reliable, is bulky and requires the attachment of the upper extremity to the trunk, followed by division and insetting of the flap at a later time. The pedicle lateral arm flap cannot reach the fingers. The reverse radial forearm flap may be harvested with skin or simply as a fascial flap. Skin grafting, either full- or split-thickness, would not be appropriate coverage for exposed joint surfaces.

Answer 28

The correct response is Option D. The sartorius muscle demonstrates a Mathes-Nahai Type IV vascular pattern with multiple segmental vascular pedicles. For this reason, it is important to preserve as many segmental pedicles as possible when transferring this flap. The sartorius flap is usually transferred as a distally based flap, and not a proximally based flap as presented in the clinical scenario. When based proximally, it is necessary to ligate multiple segmental pedicles to achieve an adequate arc of rotation, and this can lead to flap necrosis. When based distally, it is often necessary to divide 1 to 2 segmental pedicles superiorly to allow an adequate arc of rotation, but this usually does not compromise the flap. If there is any concern regarding flap perfusion, the pedicles can be temporarily clamped before division to assess the effects of pedicle ligation. Examples of muscle flaps with the other Mathes-Nahai types of vascular pattern include the following: Type I – tensor fascia lata Type II – gracilis Type III – gluteus maximus Type V – latissimus dorsi

Answer 29

The correct response is Option A. When raising a radial forearm osteofasciocutaneous flap, cortical bone should be harvested from the radial aspect of the radius between the brachioradialis and pronator teres muscle insertions. A cuff of the flexor pollicis longus to the radius is maintained to preserve the periosteal vessels. A small cuff of periosteum is maintained on both sides of the radial vessels. All of the other optional donor sites are anatomically not appropriate. A segment up to 10 cm in length and up to 40% of the cross €‘sectional area of the radius may be harvested. The superficial branch of the radial nerve, running adjacent to the brachioradialis, is at risk and is sometimes sacrificed.

Answer 30

The correct response is Option B. A delay procedure is appropriate for any patient considering TRAM flap reconstruction who has risk factors for flap loss, including obesity, a smoking history, a previous history of radiation therapy, or large volume requirements. A delayed procedure is typically performed in the outpatient setting and involves ligation of the deep and superficial inferior epigastric vessels, eliminating blood flow through the deep inferior epigastric artery. Studies of patients who have undergone this procedure demonstrated increased diameter and flow volume of the superior epigastric artery. The vascular structures within the flap are also dilated during the delay procedure. The choke vessels connect adjacent vascular regions and have been shown in animal studies to achieve maximum dilation 48 to 72 hours after surgery. Cell hypertrophy has been demonstrated within the walls of the choke vessels.

Answer 31

The correct response is Option C. The nerve supply to the medial plantar artery flap is the medial plantar nerve. The medial plantar artery flap is a sensate flap that can be used for coverage of heel defects. The flap incorporates tissue from the medial instep of the foot in a non–weight-bearing area, and can be transposed posteriorly to allow for coverage of heel defects. This flap provides durable plantar glabrous skin that can allow for weight bearing. The flap is based on the medial plantar artery, which arises from the posterior tibial artery. A branch of the medial plantar nerve providing sensation to the instep of the foot can be harvested with the flap, allowing for preservation of sensation in the reconstructed heel. The medial plantar artery flap can also be raised as a sensate free flap, with anastomosis of the medial plantar nerve to a nerve at the recipient site. The calcaneal nerve provides native sensory innervation to the heel. The lateral femoral cutaneous nerve provides sensation to the anterolateral thigh flap. The superficial peroneal nerve provides motor innervation to the lateral leg. The sural nerve provides sensation to the lateral side of the foot.

Answer 32

Correct answer is option B. The tissue requirements are determined by the nature of the wound bed and functional requirements for the site of reconstruction. Skin grafts are inappropriate in the face of exposed tendon or tendon sheath. Advancement of the volar tissue of the thumb is useful for distal thumb defects. Dissection of the skin, subcutaneous tissue, and neurovascular bundles from the underlying tissue and flexion of the interphalangeal joint allow for distal movement of the tissue for thumb pulp pad coverage. This approach would not be useful for a volar defect at the level of the proximal phalanx. The first dorsal metacarpal artery flap could be used to provide coverage of this area of the thumb. The skin and subcutaneous tissue can be elevated from the dorsum of the index finger to the level of the middle phalanx. The first dorsal metacarpal artery is included with this tissue. If a sensory flap is desired, branches of the radial nerve within the flap can be preserved or coapted to sensory nerves at the recipient site. A thenar flap would be appropriate for providing coverage for fingertips but not this region of the thumb.

Answer 33

The correct response is Option C. The most appropriate option to obtain definitive wound coverage is a fasciocutaneous free flap harvested from outside the zone of injury. Amputation is not indicated when the majority of the great toe is viable. In addition, this would be highly morbid for this young athlete. Negative pressure wound therapy alone would promote healing by secondary intention, but with an exposed joint this would likely result in an unstable wound. Local tissue rearrangement in this area results in marked donor site morbidity. Bony debridement and primary closure may lead to a healed wound, but functional morbidity would be high in this athlete.

Answer 34

Correct answer is option E. A number of options exist for the management of soft-tissue loss from the volar aspect of the fingertip. Healing by second intention can provide a durable fingertip with acceptable sensation. Unfortunately, when there is significant soft-tissue loss, there may be insufficient padding for the fingertip. The goal of intervention is to improve the bulk of the soft tissue with sensate tissue if possible. The toe pulp flap provides the best opportunity to accomplish both of these goals. The flap is harvested from the lateral aspect of the first toe or the medial aspect of the second toe. The vascular supply of the flap is the first dorsal metatarsal artery and branches of the saphenous venous system. The flap is innervated by the deep peroneal nerve and the palmar digital nerves of the toe. These nerves can be coapted to nerves of the recipient finger. Two-point discrimination of less than 10 mm can be obtained. Thenar and groin flaps involve staged transfer of soft tissue to the recipient digit. These flaps supply the desired soft-tissue bulk; however, they do not provide sensation to the transferred tissue. A cross-finger flap would supply a small amount of additional soft-tissue bulk. The flap is innervated through coaptation of dorsal digital nerves of the donor site to recipient digital nerves. Neither the sensation nor the amount of soft-tissue bulk would match that provided by the toe pulp flap. The Kutler flap entails advancement of tissue from the sides of the finger over the tip in V to Y fashion. Sensation and vascularity are maintained for this tissue. The amount of tissue that this technique provides would be modest compared to the other approaches.

Answer 35

The correct response is Option B. During a scalp advancement flap, release of the galeal aponeurosis is important, as this layer provides the majority of resistance to scalp advancement. Often scoring of the galea is performed in parallel 1-cm intervals to provide adequate release. The layers of the scalp include: skin, dense connective tissue, galeal/epicranial aponeurosis, loose areolar connective tissue, and pericranium. Release of the other layers listed is not effective, as they do not provide appreciable resistance. The innominate and the subgaleal fascia are the same layer, otherwise known as the subaponeurotic layer or the loose areolar layer. Release of this layer does not offer appreciable laxity when performing advancement flaps.

Answer 36

The correct response is Option D. The Z-plasty is a technique in which pairs of triangular transposition flaps are created adjacent to a scar and then transposed across the scar, increasing the length of the central limb and changing the orientation of the scar. This technique can be used in patients undergoing burn reconstruction to lengthen linear scar contractures, disperse linear scars, and realign scars within the lines of minimal tension. The theoretic gain in length correlates directly with the angle and length of the flap limbs. The actual gain in the length of the central axis will be decreased by 30% to 50% because of the contractile properties of skin. The theoretic gain achieved with each angle is illustrated in the table below. A 60-degree Z-plasty is performed most commonly because it produces a significant gain in length while minimizing the tension of closure.

Answer 37

The correct response is Option E. Reconstruction in this patient should be performed using the scapular flap, which will provide the greatest degree of leeway in positioning the skin paddle in relation to the bone segment. This is typically advantageous when using the flap to reconstruct complex defects of the head and neck. The scapular flap derives its primary blood supply from the circumflex scapular artery, which originates from the subscapular artery and passes through the triangular space. Branches of the circumflex scapular artery consistently supply the lateral border of the scapula at a point prior to the division of the artery into transverse and descending branches. A 3-cm vascular pedicle extends from the border of the scapula to the overlying skin and allows for an additional three degrees of spatial freedom when insetting the skin paddle. In addition, the angular branch of the thoracodorsal artery has been shown to consistently provide an independent source of perfusion to the inferior pole of the scapula. This allows for a greater arc of rotation between the bone and skin paddle because each portion derives its vascularity from separate sources. The fibular flap is based on the peroneal artery as well as its multiple periosteal vessels and cutaneous perforators; it can provide as much as 25 cm of bone for mandibular reconstruction. Because of the limited amount of skin that can be harvested with this flap, it is not often used in reconstruction without additional skin grafting; in addition, there is very little freedom in repositioning the skin relative to the bone. Harvest of this flap is contraindicated in patients with several peripheral vascular disease. The iliac crest osteocutaneous flap, which is based on the deep circumflex iliac artery, can provide a skin paddle as large as 12 cm \* 6 cm and a bone segment as large as 8 cm \* 18 cm. Although this flap can be used for reconstruction of large mandibular segments and extensive soft-tissue defects, the skin component is bulky and insensate. Meticulous closure of the donor site defect is required to prevent hernia formation. Advantages of the lateral arm flap include a thin, pliable, sensate skin paddle and the potential harvest of as much as 12 cm of skin and one third of the diameter of the humerus. Because of these factors, the flap is often used for reconstruction of defects of the head and neck or upper extremities. A skin paddle as large as 6 cm can be harvested without skin grafting. However, the use of this flap is once again limited by its lack of freedom between the skin and underlying bone segment. The radial forearm flap can provide thin, pliable skin and a maximum of 10 cm of bone, which can include a cross-sectional area comprising approximately 40% of the radius. Once again, there is minimal freedom when positioning

Answer 38

The correct response is Option D. The main advantage of the superficial circumflex iliac perforator-based (SCIP) flap over the radial forearm flap (RFF) is the improved donor site outcome. The SCIP flap can be primarily closed in most cases, whereas most RFF donor sites need a split skin graft to get closure. Additionally, the groin donor site is in a relatively hidden area compared with the RFF. The SCIP flap is a more difficult flap to raise compared with the RFF, and also has a smaller diameter and length of pedicle. Both flaps are known for being raised as thin flaps and can potentially be neurotized, with the SCIP utilizing an intercostal nerve branch, whereas the RFF uses the lateral and/or medial antebrachial cutaneous nerve(s).

Answer 39

The correct response is Option C. The medial femoral cutaneous nerve provides sensation to the anteromedial, not the anterolateral, thigh flap. Achieving durable results after reconstruction of defects on the weight-bearing surface of the foot is challenging for two main reasons: flap donor sites (other than the medial plantar artery flap) do not have the specialized skin structures of the sole of the foot and are thus less durable than native foot skin; a transferred flap will always be less sensate than native, uninjured plantar foot skin. Flaps are thus more vulnerable to trauma because they cannot feel, and they are less able to tolerate trauma because they lack the native characteristics of plantar skin. Coapting the sensory nerve of a flap to the native sensory nerve of the recipient area will allow a flap to recover some sensibility, and thus it may be more able to tolerate weight bearing. The sensory innervation to the anterolateral thigh flap is the lateral femoral cutaneous nerve. The sensory innervation to the plantar midfoot is the medial plantar nerve, a terminal branch of the tibial nerve. The superficial peroneal nerve provides sensation to the dorsal foot. The deep peroneal nerve provides sensation to the dorsal foot.

Answer 40

The correct response is Option C. The gracilis muscle arises from the anterior body and the inferior ramus of the pubis and the ischium. It passes distally in the medial thigh posterior to the long adductor and sartorius muscles and inserts on the medial aspect of the proximal tibia posterior, deep to the sartorius tendon and anterior to the semitendinous muscle insertion. Its innervation comes from a branch of the anterior division of the obturator nerve, which has 2 to 4 fascicles entering the muscle 6 to 10 cm from the origin. The obturator nerve accompanies the dominant vascular pedicle, the medial femoral circumflex artery, and its venae comitantes arising from the profunda femoris artery and vein 8 to 12 cm from the muscle origin. A vascular pedicle can be obtained that is 4 to 6 cm long with a vessel diameter of 1 to 2 mm. Two minor vascular pedicles, which are branches of the superficial femoral artery, are located distally and may be sacrificed. No significant functional loss can be seen after removal of the gracilis muscle. The transverse myocutaneous gracilis free flap with a transverse orientation of the skin paddle in the proximal third of the medial thigh region allows taking a moderate amount of tissue for autologous breast reconstruction in selected patients. The donor-site morbidity is similar to that of a classic medial thigh lift. The proximal pedicle enters the gracilis muscle 8 to 12 cm below the pubic tubercle and sends both septocutaneous and musculocutaneous perforators. These branches have a pronounced tendency to travel in a transverse direction, supplying the cutaneous territory over the long adductor and sartorius anteriorly and extending for greater than 5 cm beyond the posterior margin of the gracilis muscle. This flap is reliable and consistent.

Answer 41

The correct response is Option D. Although the lateral arm flap has predominantly been used in free tissue transfer for distant defects based on the posterior radial collateral artery, transfer as a pedicled reverse-flow flap based on the radial recurrent artery has been both anatomically and clinically proven. Occasionally, it is performed with a delay procedure at an intermediate stage. The anterior and posterior interosseous arteries can provide circulation to perforator flaps. The ulnar artery has been occasionally used for an ulnar artery based fasciocutaneous flap. The persistent median artery passes through the carpal tunnel and runs with the median nerve.

Answer 42

The correct response is Option B. The residual defect includes exposed extensor tendon without paratenon. This fact, combined with the need for flexion at the interphalangeal joint and avoidance of contracture, as well as the likely need for future tenolysis, makes a skin flap the most appropriate option for reconstruction. In the scenario described, a first dorsal metacarpal artery pedicled skin flap is used to reconstruct the thumb defect with the need for back grafting of the donor site. This provides the best combination of low donor-site morbidity, the ability to provide stable soft-tissue coverage over exposed tendon without paratenon, and the competitive advantage of being relatively easy to re-elevate for subsequent procedures, if needed. A muscle flap could be used to reconstruct the defect but would not be optimal due to the increased donor site morbidity from muscle sacrifice, as well as the increased difficulty in re-elevation versus a skin flap over tendon. Healing by secondary intention, with or without topical negative pressure wound therapy, will certainly result in extensive contracture as well as an increased time to heal. This will impact the patient’s outcome both in terms of his ability to return to work as a construction worker as well as limitations on his functional range of motion. Skin grafting, whether split- or full-thickness, is not a reliable option in this patient because of the exposed tendon without paratenon. It is important to note that this is a classic contraindication to skin grafting and therefore leads to a flap-based reconstruction. Furthermore, skin grafts would lead to increased contraction versus flaps and would be difficult to re-elevate for subsequent procedures.

Answer 43

The correct response is Option B. During harvest of the osteocutaneous radial forearm flap, a segment of radius as long as 10 cm with as much as 40% of the cross-section of the radius can be harvested. This flap can be found between the insertion of the pronator teres and brachioradialis muscles and is raised from the radial and ulnar sides. Vascularity is primarily supplied by fascioperiosteal perforators that lie within the intermuscular septum between the brachioradialis and flexor carpi radialis muscles. Musculoperiosteal branches of the flexor pollicis longus and perforators in the pronator quadratus muscle arising from the radial artery also supply blood to the flap. Dissection is performed laterally to the anterolateral intermuscular septum between the flexor carpi radialis and brachioradialis muscles and medially to the medial side of the intermuscular septum between the brachioradialis and flexor carpi radialis muscles. The brachioradialis is retracted radially and the flexor carpi radialis is retracted medially. The bellies of the flexor pollicis longus and pronator quadratus muscles are divided longitudinally to the radial periosteum, and the periosteum is incised beyond the attachments of the septum to the radius. Bone instruments are used to remove a segment of radius attached to the intermuscular septum and to the remnants of the pronator quadratus and flexor pollicis longus. The recurrent radial artery is part of the anastomotic vasculature that surrounds the elbow. The fascioperiosteal perforators lie within the intermuscular septum between the brachioradialis and flexor carpi radialis muscles, not the flexor carpi radialis and palmaris longus muscles. There are no functional perforators arising from the flexor digitorum profundus or pronator teres muscles to supply blood to the radius.

Answer 44

The correct response is Option D. The vascular pedicle for the medial sural artery perforator flap arises from the popliteal vessels. The medial sural artery flap is a thin, pliable perforator flap that can provide well vascularized soft-tissue coverage, especially for relatively small defects. It is commonly used for head/neck, hand, and lower-extremity defects. The first perforator is frequently found along a line connecting the mid-popliteal area to the medial malleolus at the 8-cm mark from the proximal end. Preoperative planning is facilitated with ultrasound identification of the perforators. Sub-fascial dissection is frequently performed to protect the perforator and blood supply and to allow for a gliding surface for tendon repairs. Donor sites that are narrower than 5 cm can frequently be closed primarily. The main benefit of the medial sural artery perforator flap over an anterolateral thigh flap is the relative thinness of the flap, which can be significant in overweight or obese patients.

Answer 45

The correct response is Option E. The pedicle for the scapular fasciocutaneous flap is the **circumflex scapular artery** arising from the subscapular system. The circumflex scapular artery travels through the **triangular space** bordered laterally by the long head of the triceps, the teres minor above and teres major below. The posterior circumflex humeral vessels travel within the quadrangular space, which is adjacent to the triangular space and is bordered by the teres minor above, teres major below, long head of the triceps medially, and the humerus laterally. The anterior triangle of the neck is bordered superiorly by the mandible, laterally by the sternocleidomastoid muscle, and medially by the midline of the neck. The contents of the anterior triangle include cranial nerves VII, IX to XII, and the carotid arteries and internal jugular vein. The posterior triangle of the neck is bordered by the trapezius muscle posteriorly, the sternocleidomastoid muscle anteriorly, and the middle third of the clavicle inferiorly. The posterior triangle of the neck contains the external jugular vein, the brachial plexus, regional lymph nodes, third part of the subclavian artery, as well as the suprascapular vessels and cervical branches of thyrocervical trunk. The posterior triangle of the neck is divided by the inferior belly of the omohyoid muscle into the occipital triangle above and subclavian triangle below. The subclavian triangle is bounded by the sternocleidomastoid, omohyoid, and the clavicle.

Answer 46

The correct response is Option A. The third perforating branch of the profunda femoris artery provides the predominant blood supply for the lateral thigh flap. The third perforating branch originates immediately caudad to the adductor brevis muscle, pierces the insertion of the adductor magnus, courses superficially, and then traverses between the biceps femoris and the vastus lateralis. It pierces the deep fascia at this point, and then emerges at the midpoint between the greater trochanter and lateral epicondyle of the femur. The lateral thigh flap is a versatile flap that has a thin, cutaneous skin paddle and is innervated by the lateral cutaneous nerve of the thigh. As much as 8 \* 25 cm can be transferred; however, split-thickness skin grafting is required for closure at the donor site if a flap with a width of greater than 8 cm is harvested. In addition, the lateral aspect of the thigh flap can be hair-bearing, especially in men, while the dermis is characteristically thick and stiff. The adductor longus muscle originates at the pubic ramus and inserts on the medial epicondyle. The gracilis muscle in the thigh is perfused by the medial circumflex artery, while the pectineus muscle receives its vascularity from the first perforating branch of the profunda femoris.

Answer 47

The correct response is Option E. The flap depicted in the photograph is the superficial inferior epigastric artery (SIEA) flap, also known as the Shaw flap. This flap derives its axial blood supply from the superficial inferior epigastric (SIE) artery, one of three cutaneous arteries supplied by the common femoral artery. The SIE artery arises from the intersection of the inguinal ligament and the femoral artery, then courses superiorly and laterally toward the anterior axillary line. The SIEA flap is typically transferred as a pedicled flap, but fasciocutaneous free tissue transfer has also been described. This flap is recommended for coverage of wounds of the hand and forearm because it lies in a relatively higher position on the torso than the groin flap; this allows for improved mobility of the shoulder while placing the elbow in a comfortable, flexed position while the flap matures. To confirm the pedicle pattern, Doppler ultrasonography can be performed prior to elevation of the flap. A photograph of the inset of the flap is shown above. The superficial circumflex iliac artery provides the axial blood supply to the groin flap. This artery also originates from the femoral artery and travels parallel to the inguinal ligament, approximately 1 cm deep to the ligament. Although the deep inferior epigastric artery supplies the rectus muscle on its deep surface, it does not supply the skin of the abdomen directly; instead, perforators emerge from the deep inferior epigastric artery and course through the rectus muscle to supply blood to the skin of the abdomen. This vascularity allows the skin and muscle to be harvested for free flap transfer. The superficial ex

Answer 48

The correct response is Option B. The gluteus maximus and rectus abdominis muscle flaps have a type III vascular pattern consisting of dual dominant pedicles. Type I muscle flaps have one dominant pedicle; examples include the gastrocnemius, tensor fascia lata, and vastus lateralis flaps. In type II muscle flaps, such as the gracilis and trapezius, there is one dominant pedicle and multiple secondary pedicles. The external oblique and sartorius muscle flaps have a type IV vascular pattern, which is characterized by a segmented blood supply. Type V muscle flaps, such as the latissimus dorsi and pectoralis major, have one dominant pedicle and multiple secondary segmental pedicles.

Answer 49

The correct response is Option D. The scapular area supplied by the circumflex scapular artery is a commonly used donor site in reconstructive microsurgery because of the consistent and reliable vascular anatomy, easily accessible pedicle, and good vessel diameter and length. The circumflex scapular artery arises from scapular artery approximately 3 to 4 cm from its origin at the axillary artery. It then passes through the triangular space, which is bordered above by the teres minor, the teres major below, and the long head of triceps laterally. Flap size can reach 10 Ã— 25 cm with generally closure of the defect directly with acceptable scarring. Parascapular osteocutaneous flaps can also be harvested using the lateral border of the scapula, which is useful for reconstruction of the hand and face.

Answer 50

The correct response is Option A. The patient described has a mutilating injury to the dorsum of the hand and wrist with exposed extensor tendons and metacarpals, which would not be an appropriate bed for a skin graft. Skin grafts survive initially by plasmatic imbibition and then by inosculation from the wound bed. Wounds with extensive exposure of tendons do not provide the potential for in-growth of vascularized tissue to maintain a skin graft. The radial forearm flap cannot be used in this patient because the palmar arch has been injured and the patient does not have communication between the radial and ulnar arterial system such that arterial compromise can occur if the radial artery is transected for the flap. Negative pressure wound therapy can be considered temporarily, but will not provide definitive management of this complex wound.

Answer 51

Correct answer is option B. The lumbar artery perforator flap is an option for autologous breast reconstruction. Within the flap, the cluneal nerve can be harvested for sensation. The flap is based off of the lumbar artery perforator (L4), which runs lateral to the erector spinae muscle, with the quadratus lumborum muscle on the other side. The perforator does not run in between the other muscles listed. 1. Stillaert FBJL, Opsomer D, Blondeel PN, Van Landuyt K. The lumbar artery perforator flap in breast reconstruction. Plast Reconstr Surg. 2023;151(1):41-44. doi:10.1097/PRS.0000000000009782 2. Peters KT, Blondeel PN, Lobo F, van Landuyt K. Early experience with the free lumbar artery perforator flap for breast reconstruction. J Plast Reconstr Aesthet Surg. 2015;68(8):1112-1119

Answer 52

The correct response is Option C. Abnormally elevated rheologic factors associated with hematologic disorders such as sickle cell disease can seriously compromise perfusion. This usually happens in the form of sludging within the vessel lumen, causing flap compromise. Microvascular surgery in young patients was once considered high risk because of misconceptions of higher sympathetic tone and higher propensity for spasm. This has been proven false. Many studies have proven microvascular surgery to be safe for children. Humoral factors such as prostaglandin I2 (prostacyclin) and E1, as well as histamine and bradykinin, cause vasodilation. Local factors such as acidosis, hyperthermia, and hypercapnia cause vasodilation.

Answer 53

The correct response is Option B. The posterior interosseous flap is a pedicled forearm flap based off the posterior interosseous artery (PIA) proximally. It can be rotated to cover elbow, antecubital fossa, or proximal volar forearm defects. A reversed version, based off the anterior interosseous arterial connections to the PIA, can be used for wrist and hand defects. The PIA emerges in the proximal dorsal forearm deep to the supinator. It then courses between the extensor carpi ulnaris (ECU) and the extensor digiti minimi (EDM). During dissection of a standard posterior interosseous flap, the pedicle is found distally in the forearm between the ECU and EDM then dissected proximally. The superficial branch of the radial nerve is located anterior to the pronator teres and deep to the brachioradialis. The anterior interosseous artery is found between the muscle bellies of flexor digitorum profundus and the flexor pollicis longus. Distally in the forearm, the radial artery is deep to the brachioradialis and radial to the flexor carpi radialis. Proximally in the forearm, the posterior cutaneous nerve of the forearm is found superficial to both the anconeus and extensor digitorum muscle.

Answer 54

The correct response is Option A. Reconstruction of the weightbearing plantar surface ideally requires skin that is sensate and glabrous. When possible, replacing like-with-like tissue is preferred. The donor site for the **medial plantar artery flap** is located on the non-weightbearing plantar surface and provides tissue that is structurally similar to the plantar area of the hind foot including fibro-fatty subcutaneous tissue and plantar fascia. The **medial plantar artery** is a terminal branch of the *posterior tibial artery*, and lies between the *abductor hallucis* and *flexor digitorum brevis*. Fibers of the medial plantar nerve can be harvested with the flap to provide sensation. The flap can also be raised as a distally-based flap from retrograde flow through the **lateral plantar artery** for forefoot wounds, or as a free flap. This flap has been shown to provide reliable reconstruction of the plantar surfaces. The lateral plantar artery runs between the *flexor digitorum brevis* and *abductor digiti minimi*. The dorsalis pedis artery runs between the extensor hallucis longus and extensor digitorum longus tendons. The remaining muscle intervals do not contain any major arterial branches used in flap reconstruction.

Answer 55

The correct response is Option A. In order to effectively identify the gracilis muscle prior to flap harvest, the patient should be placed in the supine position with the knee in abduction. With the patient in this position, the adductor longus muscle can be palpated before surgery. Following incision, the gracilis muscle is easily identified posterior to the adductor longus. The adductor magnus muscle lies posterior to the gracilis, and the pectineus muscle is found anterior to the adductor longus at the floor of the femoral triangle. The sartorius muscle overlies the gracilis muscle distally.

Answer 56

The correct response is Option A. The predominant blood supply of the inferior portion of the trapezius myocutaneous flap is the dorsal scapular artery. The dorsal scapular artery is a separate branch of the subclavian artery or forms a common trunk with the superficial cervical artery. When a common trunk is present, it is referred to as the transverse cervical artery, the superficial cervical artery as the superficial branch of the transverse cervical artery, and the dorsal scapular artery as the deep branch of the transverse cervical artery. The superior or descending part of the trapezius is supplied by branches of the occipital artery. The middle or transverse part is supplied by the superficial cervical artery. The thoracoacromial artery supplies the pectoralis major muscle flap and the thoracodorsal artery supplies the latissimus dorsi muscle flap.

Answer 57

The correct response is Option A. Because the buccinator muscle is sandwiched between the facial artery and the oral mucosa, it must be included in a facial artery musculomucosal flap. The buccinator muscle originates from the pterygomandibular raphe and inserts into the orbicularis oris muscle and mucosa of the lateral lip elements. The other muscles listed are supplied by the facial nerve but are not included in a facial artery musculomucosal flap because of their location. The depressor anguli oris and zygomaticus major muscles lie superficial to the plane of dissection for this flap. The levator labii superioris muscle inserts into the lateral half of the lip, but its origin is from the infraorbital margin of the maxilla. The orbicularis oris muscle is anterior to the plane of dissection for the facial artery musculomucosal flap.

Answer 58

The correct response is Option A. The anterolateral thigh (ALT) free flap (shown) is the only option listed with the requisite tissue characteristics, size, and pedicle length necessary to repair a defect of this size and location. The ALT flap has rapidly become a first-line option for covering large or irregular head and neck defects. It is an extremely versatile flap with chimeric options allowing for multiple skin paddles, muscle bulk (vastus lateralis) if needed for dead space obliteration, as well as bone (iliac crest) for midface or small mandibular defects. The tissue thickness is well suited for large scalp defects. Flaps as large as 35 × 25 cm have been described, although defects larger than 10 to 12 cm in width generally require skin grafting the donor site. Pedicle lengths of 12 to 16 cm have been described, which is often long enough to reach the upper neck if necessary. The radial forearm free flap is an excellent option in many cases, providing a pedicle length up to 18 to 20 cm with maximal dimensions up to 12 × 30 cm. A major criticism of this flap is the poor cosmesis of the donor site and lack of subcutaneous tissue necessary to match the surrounding cutaneous defect. The lateral arm flap based on the radial collateral artery is useful for smaller defects in the head and neck but is limited in this situation by a short pedicle (6 cm) and smaller skin paddle (6 × 12 cm). Muscle flaps covered with skin grafts have also been described for scalp coverage. When necessary, a latissimus dorsi flap is a great option for near total scalp coverage. With the examples listed here, the gracilis flap is too narrow (5 to 6 cm) with too short a pedicle (medial femoral circumflex, 7 cm). While the pedicle for the rectus free flap (deep inferior epigastric, 8 to 10 cm) might be long enough in this situation, the muscle is not big enough (6 cm wide) to cover the defect.

Answer 59

The correct response is Option C. Although fluorescein 15 mg/kg is often administered intravenously to determine the viability of a flap's skin paddles, this cannot be used for continuous free flap monitoring because fluorescein often takes several hours to clear from the skin. Lower doses of fluorescein can be used for sequential monitoring, but not for continuous monitoring. Each of the other options listed can be used for continuous flap monitoring. Although external Doppler ultrasonography is the most frequent choice for flap monitoring, difficulties can be experienced when the flap pedicle is located close to a large artery. External Doppler ultrasonography also cannot be used with buried flaps. Differential surface temperature monitoring compares the temperature of the transferred tissue with the normal surrounding tissue. A temperature difference of greater than 1.8%C (35.3%F) is believed to be significant. Laser Doppler ultrasonography and photoplethysmography both involve the measurement of reflected light from a source that penetrates the flap.

Answer 60

The correct response is Option E. In a patient who has a chronic, irradiated wound, the most appropriate management is coverage with a muscle or musculocutaneous flap with a vascular pedicle that lies outside the field of radiation, such as the gracilis flap. Secondary intention healing is unlikely to be successful in a radiated wound bed, and primary closure of a previously radiated, nonhealing wound will also not result in appropriate healing. Skin grafting will be ineffective due to the poor vascularity of the wound bed. A fasciocutaneous flap is less appropriate than a muscle flap to fill the dead space within the wound.

Answer 61

Correct answer is option A. Small, dorsal defects of the fingers can be reconstructed via a number of local flaps; as in many other parts of the body, adipofascial turnover flaps have been developed for the upper extremity, hand, and fingers. Advantages of these flaps include almost limitless donor sites, single stage reconstruction, and minimal donor site morbidity. For coverage of dorsal digital defects, adipofascial turnover flaps are designed with the base of the flap proximal to the defect. The flap itself is designed to be 2 to 4 mm wider than the skin defect with a base to length ratio of 1:1.5 to 1:3. A longitudinal incision over the center of the flap allows dissection of the flap from the overlying skin. The adipofascial flap is then elevated from proximal to distal from the underlying paratenon. Elevation stops approximately 0.5 to 1 cm proximal to the defect to create the base of the flap; the flap is then turned over into the digital defect and covered with a split thickness skin graft (see the figure below). Given the damage to the adjacent long finger, a cross finger flap would not be possible. A transposition flap from the dorsal thumb may suffice for first web resurfacing but will not adequately reach the dorsal index finger. Both the posterior interosseous artery and radial-artery based flaps are capable of resurfacing sizable defects on the hand and fingers; however, the added morbidity of harvesting these flaps does not warrant their use when a more suitable local flap is available.

Answer 62

The correct response is Option C. The correct answer is the posterior radial collateral artery, which is a branch of the profundus brachial artery. The profundus brachial artery arises from the brachial artery and accompanies the radial nerve. The posterior radial collateral artery passes posterior to the lateral intramuscular septum between the deltoid tubercle and epicondyle. The flap can be harvested from the same extremity, offering pliable tissue for soft-tissue coverage. The lateral arm flap also may be taken with muscle, bone, or cutaneous nerves for composite tissue reconstruction. The anterior interosseous artery supplies the posterior interosseous artery flap (via its connection to the posterior interosseous artery through the distal interosseous membrane) located on the dorsum of the forearm. This flap may be reversed to cover small to moderate defects on the dorsum of the hand. The superior ulnar collateral artery arises from the brachial artery in the upper arm. This artery is the blood supply of the medial arm flap. The medial arm flap offers the advantage of a well-hidden donor site; however, flap dissection may be extremely tedious and the flap may have significant subcutaneous fat. The inferior cubital cutaneous artery may be used as a source of a fascial cutaneous flap in the forearm. The radial recurrent artery arises from the radial artery below the elbow. This artery anastomoses with the radial collateral artery and can be used as a reversed pedicle flap of the lateral arm skin. This flap may reach to the level of the mid-forearm but cannot reach the hand.

Answer 63

The correct response is Option A. The omental flap is supplied by the gastroepiploic vessels. Common options for sternal wound reconstruction include the pectoralis major, rectus abdominis, latissimus dorsi, and omental flaps. The use of an omental flap for a mediastinal defect was described in the 1970s; however, muscle flaps became a popular choice for reconstruction in the 1980s. Based on the size of the defect, the omental flap can be used with or without a skin graft. The omentum has angiogenic and immunogenic properties that make it ideal for reconstruction of sternal wound infections. The omentum is based on the left and right gastroepiploic vessels. In order to increase length, the flap can be based on one set of vessels, usually the right gastroepiploic vessels. The left gastroepiploic vessels are a branch of the splenic vessels; the right gastroepiploic vessels are a branch of the gastroduodenal vessels. Harvest can be performed through either an upper abdominal incision, transdiaphragmatic, or laparoscopically. There is a risk of donor site morbidity such as abdominal wound infections or symptomatic hernias. The superior mesenteric vessels supply the lower part of the duodenum extending to the middle third of the transverse colon, as well as the pancreas. The left and right gastric vessels supply the lesser curvature of the stomach. The short gastric vessels supply a portion of the greater curvature of the stomach and are branches of the splenic vessels. The left and right gastroepiploic vessels supply the greater curvature of the stomach along with the omentum.

Answer 64

The correct response is Option E. The anterolateral thigh flap is a versatile coverage tool because of its wide skin island (up to 8 x 25 cm) and long, accessible pedicle (up to 7 cm). The blood supply originates from the lateral femoral circumflex artery descending branch, and sends perforating branches through the vastus lateralis and rectus femoris muscles, and occasionally through the intermuscular septum. The inferior gluteal muscle, while a common muscle flap, is further posterior and proximal. The tensor fascia lata is more lateral to the anterolateral thigh flap zone, though it also has a blood supply from the lateral femoral circumflex system, as the vessel terminates in the tensor fascia lata. The sartorius is more medial and proximal and has a segmental circulation based on the femoral artery branches. The gracilis is more medially based, and is supplied by the medial femoral circumflex.

Answer 65

The correct response is Option C. An adequate perforator is not found on dissection of the anterolateral thigh (ALT) free flap in up to 5% of cases. When an ALT flap perforator traveling between the rectus femoris and vastus lateralis or through the vastus lateralis to supply the anterolateral thigh skin is not found, there is a higher chance of finding a perforator that supplies the anteromedial thigh skin. This perforator, present in about 50% of thighs, most commonly arises from the descending branch of the lateral circumflex femoral artery, via a branch that supplies the rectus femoris muscle. This perforator can take a course through the rectus femoris or between the rectus femoris and vastus medialis. Alternately, one or more anteromedial thigh perforators may arise directly from the superficial femoral artery. When an ALT perforator cannot be located, the surgeon may salvage the situation by changing to an anteromedial thigh (AMT) free flap rather than exploring another donor site. Another alternative is to harvest a tensor fascial lata free flap, based on the ascending branch of the lateral circumflex femoral artery. The medial circumflex femoral artery, common femoral artery, and profunda femoris artery do not give rise to previously described cutaneous perforator flaps. Reference(s) 1. Namgoong S, Yoon YD, Yoo KH, Han SK, Kim WK, Dhong ES. Alternative choices for anterolateral thigh flaps lacking suitable perforators: a systematic review. J Reconstr Microsurg. 2018;34(7):465-471. 2. Yu P. Inverse relationship of the anterolateral and anteromedial thigh flap perforator anatomy. J Reconstr Microsurg. 2014;30(7):463-468. 3. Yu P, Selber J. Perforator patterns of the anteromedial thigh flap. Plast Reconstr Surg. 2011;128(3):151e-157e.

Answer 66

The correct response is Option A. The rectus femoris flap provides reliable and robust soft tissue for coverage of abdominal, groin, and hip defects. Because the rectus femoris is one of the quadriceps muscles and inserts into the patella, its use can have functional consequences. It is generally recommended to perform patellar tendon repair following harvest of the rectus femoris; despite this repair, there can still be about 15 degrees of extensor lag at the knee. Flexion contracture of the hip, difficulty standing for extended periods, and difficulty adducting the leg have not been described with this flap harvest. The expanded rectus femoris flap has several advantages for massive abdominal wall reconstruction. The expanded flap easily can reach the xiphoid, and it has impressive width. The donor site can be closed primarily with an acceptable scar. The muscle remains innervated and functional, which may help prevent bulging. Large or complicated abdominal wall defects caused by recurrent incisional hernias, infections, or tumor resections often require the use of prosthetic mesh, local tissue transposition, or even distant muscle flaps for proper reconstruction. In a series of 12 cases of reconstruction of the abdominal wall using pedicled rectus femoris muscle flaps for wounds resulting after tumor resections, recurrent incisional hernias, and infection, abdominal wall stability and donor site morbidity were examined clinically. Follow-up time ranged from 6 months to 4 years. In all but one patient, a stable abdominal wall could be reconstructed. The loss of true muscular capacity in the quadriceps muscle of the operated leg was 19% compared with the nonoperated leg, but this result was tolerated well.

Answer 67

Correct answer is option B. Venous flow through flaps (VFTFs) are unusual but are gaining acceptance for certain kinds of hand and finger wounds. The ideal site for coverage with a VFTF is a long and narrow defect needing thin soft tissue. VFTFs typically become congested in the first week and then decongest over the following two weeks as they revascularize from the wound bed. VFTFs cannot reliably transfer composite tissue such as bone and tendon or cover a wide defect such as an entire palm. Because VFTFs do not bring in vascularization to the wound bed as well as classic flaps, they are not indicated in radiated or potentially infected wound beds. A small defect such as the 2-cm defect needing coverage during the replantation of the finger in the scenario described is the ideal candidate for this flap. When compared with simple vein grafts, VFTFs are not associated with increased rates of arterial thrombosis, failure of replantation, or hematoma. Although VFTFs are more susceptible to infection than typical flaps, congestion of the flap with superior epidermolysis is a much more likely complication.

Answer 68

The correct response is Option B. Exposed bone does not provide an adequately vascularized bed for skin graft take. Pericranium, in contrast, can support a skin graft. The presence of granulation tissue is a good sign that the wound bed is adequately vascularized for a skin graft to take. Surrounding alopecia decreases aesthetic concerns associated with reconstructive options that do not support hair growth. Defect location does not significantly affect the need for vascularized coverage.

Answer 69

Correct answer is option D. The Mathes and Nahai classification of muscle flaps is based on vascular supply. Type III muscles have two dominant pedicles. The rectus abdominis muscle is supplied by both the superior and inferior deep epigastric vessels. The superior epigastric pedicle is an extension of the internal mammary circulation and allows transposition of the rectus muscle to the chest for breast and thoracic reconstruction. Pedicle flaps based on the inferior circulation are useful for pelvic and abdominal reconstruction. If one end of the muscle is in the zone of injury and the other side is spared, then a portion of the muscle could still be available for flap transfer. The gastrocnemius muscle flap is an example of a type I flap, having a single dominant circulation. Injury to the upper posterior calf would preclude safe use as a flap. Both the latissimus and pectoralis major muscles are type V, containing both a dominant pedicle as well as a group of smaller, equally sized segmental vessels. These muscles may be elevated as flaps based on either the dominant circulation or on the group of segmental vessels, and therefore, also provide a degree of versatility. The sartorius muscle is classified as type IV, having only a segmental circulation of multiple pedicles of equal size rather a dominant pedicle. The sartorius muscle is useful for coverage of the femoral sheath after a vascular surgical wound dehiscence with exposed prosthetic graft. Type II muscle flaps have both a dominant pedicle and a minor circulation. The minor vessels are typically divided to allow use of a flap based on the dominant pedicle. Examples include the gracilis and biceps femoris muscles.

Answer 70

The correct response is Option A. Ischial pressure ulcers can be one of the most difficult wounds for which to achieve long-term coverage and success. The best outcomes arise from multidisciplinary care teams that focus on pressure alleviation (both perioperative and chronic), nutrition, smoking cessation, muscle spasm management, and vigilant observation. Despite best efforts, ischial pressure ulcers still have up to a 70% recurrence rate. Because of high recurrence rates, surgical planning needs take potential future wounds into consideration. Large rotation or advancement flaps have the benefit of being able to be re-rotated or re-advanced, whereas transposition flaps do not, and can make future surgery more difficult. With good surgical planning, rotation and transposition flaps would not have a difference in vascularity, scar placement, pressure relief, or recurrence rates.

Answer 71

The correct response is Option E. A 60-degree z-plasty lengthens a scar by 75%. If each z-plasty covers 4 cm of scar, each will lengthen the scar by 3 cm, for a total increase of 9 cm. In contrast, a 30-degree z-plasty lengthens an incision by 25%, and a 45-degree z-plasty lengthens an incision by 50%. To prevent undue tension, angles greater than 60 degrees should be avoided.

Answer 72

Correct answer is option C. Unlike the other tissues, the trapezius muscle is based on the transverse cervical artery (based on the thyrocervical trunk in 80% of cases or the subclavian artery in 20% of cases). The subscapular system allows for the creation of chimeric flaps that can include bone, muscle, fascia, fat, and skin. Flaps that have been used include the serratus anterior muscle and fascia, latissimus dorsi muscle and fascia, scapular and parascapular fascia and overlying skin, and scapular and rib bone. Such combinations allow for versatility in reconstructing complex three dimensional defects that are often encountered in the face.

Answer 73

The correct response is Option C. The gracilis muscle is a useful flap for perineal reconstruction. It was first described for use in rectourethral fistula repair by Ryan et al. in 1979. The gracilis muscle is the most superficial of the adductor group and can easily be found in the mid thigh, traversing between the pubic tubercle and medial femoral condyle. Its blood supply is from the profunda femoris as a direct branch or terminal branch of the medial femoral circumflex. There are multiple additional minor pedicles along the muscle’s length (Mathes and Nahai type II). The dominant pedicle enters the muscle approximately a handbreadth below the inguinal crease. It enters the deep aspect of the muscle (ie, from lateral to medial) making dissection of the superficial muscle safe and easy.

Answer 74

E ) Prothrombin time (PT) The correct response is Option D. The most appropriate test is a platelet count to determine the possibility of heparin-induced thrombocytopenia (HIT) with thrombosis. This immune-mediated complication can occur in up to 3 to 5% of patients on heparin therapy, especially those previously exposed to heparin within the last 3 months of the second exposure. Approximately 20% of patients with HIT will have thrombotic events with potentially devastating consequences: 30% mortality and 30% limb loss. The pathogenesis of HIT involves the formation of multimolecular complexes between heparin and platelet factor 4. In some patients, immunoglobulin G-class antibodies are generated against the heparin: platelet factor 4 complexes. This results in potent platelet activation, platelet aggregation, and a marked increase in thrombin generation. The key to successful treatment is early recognition, and clinical diagnosis remains the €œgold standard. € A 30% decrease in baseline platelet count combined with any form of thrombosis in a patient receiving heparin should be considered heparin-induced thrombocytopenia and thrombosis until proven otherwise. The most essential element in the treatment of heparin-induced thrombocytopenia and heparin-induced thrombocytopenia and thrombosis remains discontinuation of all heparin, including heparin line flushes, subcutaneous heparin, and heparin-coated indwelling catheters. Starting alternative anticoagulant therapy (eg, danaparoid sodium, lepirudin, or argatroban) as soon as there is a strong clinical suspicion of HIT is advocated. This should be continued until platelet levels have returned to baseline. Although HIT is typically diagnosed on the basis of clinical signs, the diagnosis should be confirmed by laboratory testing whenever possible (platelet aggregation test and/or specific heparin-platelet factor 4 enzyme-linked immunosorbent assay [ELISA] assay). In this patient, knowing if he may have HIT with thrombosis is essential because stopping the heparin drip becomes paramount. D-dimer is a fibrin degradation product that is elevated in the presence of thrombosis. Factor V Leiden is the name given to a variant of factor V that causes hypercoagulability. Genetic tests are done to confirm this. PT is a measure of the extrinsic pathway of coagulation, and aPTT is a measure of both the intrinsic and common pathways of coagulation.

Answer 75

The correct response is Option B Flaps require preservation of the defined arterial and venous supply. Regional flaps can be based distally or proximally. The lateral arm flap was initially described by Song and popularized by Matloub, et al. and Katsaros, et al. This flap has considerable application in reconstruction of the upper extremity. It can be harvested from the same extremity; it has thin, pliable skin; and it can be innervated. The lateral arm flap can also include a segment of vascularized humerus or a segment of vascularized triceps tendon. The flap can also be segmentally contoured for hand defects. The lateral arm free flap is based on the posterior radial collateral artery, which is a branch of the profunda brachial artery. A reversed pedicled lateral arm flap can also be performed. This reverse flap is based on the radial recurrent artery. The superior ulnar collateral artery is the dominant pedicle of the medial arm flap. The medial arm flap is also useful for upper extremity coverage, but there are significant variations in the superior ulnar collateral artery which makes this flap a less-than-optimal choice for microvascular surgical reconstruction. The posterior interosseous artery is the dominant blood supply of the posterior interosseous artery flap. The posterior interosseous artery flap is also used for reconstruction of the hand because it has thin, pliable skin. As a pedicle flap, it can cover the wrist and extend to the first web space. Use of the posterior interosseous flap can compromise motor nerves to the extensor carpi ulnaris or extensor digiti quinti.

Answer 76

The correct response is Option D. The most appropriate method for wound coverage is a local tissue flap, which could come from the intact medial upper arm and/or ulnar aspect of the forearm. A split-thickness skin graft is not appropriate coverage for vital structures. The time it takes for a dermal substitute to vascularize and form the basis of subsequent grafting is too long to leave such vital structures exposed. Free tissue transfer is an option; however, this patient is 2 weeks out from injury and the associated hypercoagulable state is a relative contraindication if local tissues are available. Above-elbow amputation is not an appropriate option as the hand is spared and there are viable coverage options for this young manual laborer.

Answer 77

The correct response is Option D. The flap described in this scenario is a prelaminated flap. A prelaminated flap is an axial flap that is modified with the addition of various grafts (e.g., skin, mucosa, cartilage, bone), re-creating the missing tissues at the donor site prior to flap transfer. A delayed flap is one that undergoes one or more vascular insults prior to final flap elevation to induce increased circulation and maximize flap perfusion. A freestyle flap is a nonaxial flap harvested by locating a cutaneous Doppler signal in a chosen donor site, identifying the vessels supplying that tissue, and dissecting them down to a pedicle of sufficient length and/or diameter. The anatomy is not known ahead of time, and thus harvest is performed ?freestyle.? A prefabricated flap is created by transferring a vascular pedicle into an area of tissue that is ideal for transfer to induce angiogenesis from the pedicle into that tissue, which can then be harvested for transfer. A tubularized flap is one that is sewn to itself to create a tube or passive conduit, such as an anterolateral thigh flap used for pharyngoesophageal reconstruction.

Answer 78

The correct response is Option A. There has been recent increased interest in the use of the medial condyle of the femur as a source of vascularized bone. The blood supply appears to be robust and predictable. In one study, the descending genicular artery was present in 89%, and the superior medial genicular artery was present in 100% of specimens with average distances proximal to the articular surface of 13.7 cm and 5.2 cm, respectively. The posterior radial collateral artery is the pedicle for the lateral arm flap. The sural artery perfuses the posterior skin of the calf. The medial femoral circumflex artery lies in the upper thigh and helps supply blood to the neck of the femur. The posterior tibial artery carries blood to the plantar surface of the foot from the posterior artery.

Answer 79

The correct response is Option C. In this 25-year-old woman who has a 6 \* 4-cm defect of the posterior aspect of the scalp, the most appropriate management is coverage of the defect using a rotation flap. This flap provides local hair-bearing tissue and can be used to cover defects as large as 6 cm. In order to advance an adequate length of flap, multiple relaxing incisions must be performed within the galea. If the galea is not carefully divided, injury to the subcutaneous vessels or hair follicles may result, leading to the onset of alopecia or delayed wound healing. Tissue expansion is most appropriate for patients who have large defects of the scalp (typically greater than 15%) because the scalp defect will be covered with similar tissue. Donor site scarring is not a factor in most cases, and the expanders can be left in place if further tissue expansion is required. In addition, the hair follicles will be oriented correctly; as much as 50% of the scalp can be covered with expanded tissue without altering hair growth. However, the process of tissue expansion involves multiple procedures and frequent office visits over a lengthy period of time. During the expansion process, the patient often expresses displeasure with his/her physical appearance. Excision and primary closure combined with extensive undermining are only appropriate for patients who have defects measuring less than 5 cm. Patients with small areas of scalp alopecia may undergo multiple staged excisions of the alopecic scalp followed by advancement of hair-bearing tissue. Because this process involves fewer procedures and less follow-up, it can be used as an alternative to tissue expansion. Although a full-thickness skin graft can be used for temporary wound coverage in a patient who will undergo further scalp reconstruction, it is not an appropriate long-term treatment because many donor sites do not provide adequate hair-bearing skin. Hair transplantation is currently being used with increasing regularity for treatment of traumatic or age-related alopecia.

Answer 80

The correct response is Option C. The lateral arm flap is a reliable fasciocutaneous flap used for reconstruction of small to medium size soft-tissue defects of the forearm and hand. It provides thin tissue of excellent quality and a satisfactory aesthetic outcome with the ability for primary closure of the donor site. The dominant pedicle is the **posterior radial collateral artery**. This vessel originates from the radial collateral artery which is a branch of the brachial artery in the upper arm and *emerges between the brachialis muscle anteriorly and the lateral head of the triceps posteriorly* to supply the skin and soft tissue of the lateral arm. In addition, the anatomic relationships between the vascular pedicle and radial nerve are important to understand when dissecting this flap. The radial nerve courses posterior to the humerus before wrapping around the lateral aspect of the humerus from posterior to anterior. The *antebrachial cutaneous nerve of the forearm branches from the radial nerve to join the vascular pedicle (posterior branch of radial collateral artery).* This cutaneous nerve can be preserved with careful dissection and helps to identify the radial nerve proximally during flap elevation. Segmental perforating vessels emerge within the septum separating the triceps and brachialis muscles.

Answer 81

The correct response is Option A. The dominant pedicle of the gracilis muscle flap is located between the adductor longus and adductor brevis muscles. The pectineus, adductor magnus, sartorius, and semitendinosus muscles are anatomically incorrect relative to the location of this pedicle. Although the origin of the dominant vascular pedicle to the gracilis muscle flap may originate from either the profundus femoris or medial circumflex femoral vessels, the course of this vascular pedicle is consistent and runs between the adductor longus and adductor brevis muscles. This vascular pedicle enters the gracilis muscle approximately 8 to 10 cm below the pubic tubercle. The superficial position of the gracilis muscle, its thin, ribbon €‘like character, and also its consistent vascular anatomy allow this muscle flap to remain one of the most useful muscles in the field of microvascular surgery. Although the dominant vascular pedicle easily nourishes the entire muscle, the distal third of the skin overlying the gracilis muscle does not receive sufficient blood supply for reliable transfer.

Answer 82

Correct answer is option D. The scapular area supplied by the circumflex scapular artery is a commonly used donor site in reconstructive microsurgery because of the consistent and reliable vascular anatomy, easily accessible pedicle, and good vessel diameter and length. The circumflex scapular artery arises from scapular artery approximately 3 to 4 cm from its origin at the axillary artery. It then passes through the triangular space, which is bordered above by the teres minor, the teres major below, and the long head of triceps laterally. Flap size can reach 10-25 cm with generally closure of the defect directly with acceptable scarring. Parascapular osteocutaneous flaps can also be harvested using the lateral border of the scapula, which is useful for reconstruction of the hand and face.

Answer 83

The correct response is Option E. Vibration is a modality that may be used in therapy to desensitize an amputation stump neuroma. The treatment consists of vibratory stimulation applied to the periphery of the sensitive area and then gradually moving toward the center. Some additional methods used in therapy to treat neuroma pain include desensitization, massage, and transcutaneous nerve stimulation. Functional electric stimulation is similarly not a therapeutic modality. Kinesiology taping is used for edema control and comfort. It would not be used on an amputated stump. Semmes-Weinstein monofilaments are used to quantify sensation to fine touch and are not used for desensitization.

Answer 84

The correct response is Option D. The sartorius muscle would provide the most reliable option for wound coverage for the patient discussed. The sartorius muscle flap originates from the anterior iliac spine and inserts into the medial tibia. Eight to eleven perforators off the superficial femoral artery segmentally supply the sartorius, a type V muscle flap. The proximal pedicle is located approximately 6 cm from the anterior superior iliac spine. The sartorius muscle is adjacent to the femoral vessels. The anterior lateral thigh, rectus femoris, and vastus lateralis muscles all are supplied by branches of the lateral femoral circumflex vessel. The gracilis muscle is supplied by the medial femoral circumflex artery. Both medial and lateral circumflex arterial branches originate from the proximal portion of the profunda femoris artery. Occlusion of the profunda would make the use of these flaps risky and may result in flap loss. The rectus femoris muscle is a type I muscle flap with a single dominant blood supply from the lateral femoral circumflex artery.

Answer 85

The correct response is Option D. The major blood supply to the pectoralis major myocutaneous flap is the thoracoacromial artery. This flap has been the workhorse for head and neck reconstruction. It remains a lifeboat flap for microvascular flap failures in the area. It arises from the second part of the axillary artery (continuation of the subclavian artery) and divides into four branches with the pectoral branch supplying the pectoral muscles and the flap. The superior thoracic artery arises from the first part of the axillary artery and also supplies some part of the pectoral muscles. The lateral thoracic artery also arises from the axillary artery but does not supply the flap. The internal mammary artery does supply the pectoralis major muscle and its accompanying skin; however, it cannot be pedicled on this axis for head and neck reconstruction. The transverse cervical artery originates from the subclavian artery and supplies the muscles of the neck and scapula.

Answer 86

The correct response is Option D. This patient has hemifacial atrophy, or Parry-Romberg syndrome. Parry-Romberg syndrome is a progressive hemifacial atrophy that can be associated with ocular and neurologic symptoms. The treatment of Parry-Romberg syndrome varies depending on the degree of bony and soft-tissue defect. Fat grafting, alloplastic implants, and free tissue transfer have all been described for correction of the deformity. For larger soft-tissue defects, free tissue transfer may be required. In a study of 177 free flaps, the most common short-term complication associated with free tissue transfer for Parry-Romberg syndrome is hematoma, which occurred in 7% of patients. Flap loss (partial or complete), cellulitis, and facial skin slough were noted in less than 1% of the patients. Overcorrection and the need for debulking/refinement is an expected outcome for this procedure. Reference(s) 1. Chen JT, Schmid DB, Israel JS, Siebert JW. A 26-year experience with microsurgical reconstruction of hemifacial atrophy and linear scleroderma. Plast Reconst Surg. 2018;142(5):1275-1283. 2. Palmero ML, Uziel Y, Laxer RM, Forrest CR, Pope E. En coup de sabre scleroderma and Parry-Romberg syndrome in adolescents: surgical options and patient-related outcomes. J Rheumatol. 2010;37(10):2174-2179. 3. Si L, Zeng A, Qiao Q, et al. Microsurgical correction of progressive facial hemiatrophy using free anterolateral thigh adipofascial flap. J Craniofac Surg. 2012;23(7)(suppl 1):2051-2056.

Answer 87

The correct response is Option E. The anterolateral thigh flap is based on the descending branch of the lateral femoral circumflex vessels. Although classically thought of as providing septocutaneous perforators between the rectus femoris and the vastus lateralis muscle, increased familiarity with this flap and critical anatomical evaluation have shown that its perforators are primarily musculocutaneous through the vastus lateralis in the majority of cases. This anatomy is important to understand during flap elevation and harvest. Surgeons unfamiliar with these anatomical variations may find it confusing if no septocutaneous perforators are identified. They may unnecessarily abandon the anterolateral thigh flap because of this. However, once musculocutaneous perforators are found, it may be safer to harvest a cuff of vastus lateralis muscle with the perforators to maximize perfusion, as an intramuscular dissection can be tedious and risks damage to the perforators.

Answer 88

The correct response is Option E. In a patient who has a chronic, irradiated wound, the most appropriate management is coverage with a muscle or musculocutaneous flap with a vascular pedicle that lies outside the field of radiation, such as the gracilis flap. Secondary intention healing is unlikely to be successful in a radiated wound bed, and primary closure of a previously radiated, nonhealing wound will also not result in appropriate healing. Skin grafting will be ineffective due to the poor vascularity of the wound bed. A fasciocutaneous flap is less appropriate than a muscle flap to fill the dead space within the wound.

Answer 89

A 40-year-old man sustains burns to 35% of his total body surface area, including the neck, chest, axillae, and upper extremities. After subsequent skin grafting, a right anterior axillary dome scar contracture develops. The patient is scheduled to undergo revision of the scar using Z-plasty. Which of the following lateral limb angles will result in a theoretical 75% gain in central limb length? ## Footnote A) 30 degree B) 45 degree C) 60 degree D) 75 degree E) 90 degree The correct response is Option C. The traditional standard Z-plasty consists of at least three incisions of equal length (two limbs and one central incision) and two angles of equal degree. Ideally, the central incision runs parallel to the long axis of the scar, or the scar itself may be completely excised with the fusiform defect acting as the central incision. The resultant subcutaneous triangular skin flaps are transposed with each other such that the new, central incision lies perpendicular to the original central incision. After closure, the scar is reoriented along the limb incisions, and the new central incision lies within relaxed skin tension lines. The length of the original scar also increases after a Z-plasty, which is a useful characteristic when a surgeon desires release of a scar contracture, as in this specific example. In general, as the central incision lengthens (given a constant angle), so does the resultant scar. Additionally, as the angles between the limbs increase (given a constant limb length), so does the resultant scar.

Answer 90

The correct response is Option D. The triceps, teres major, and teres minor muscles comprise the borders of the triangular space. A knowledge of this region is essential to harvest the scapular and parascapular flaps, which receive their blood supply from the circumflex scapular artery. The pedicle of the parascapular flap arises from the triangular space and enters the deep surface of the flap. The other muscles listed above can be identified in the region of the shoulder and trunk but do not define the triangular space.

Answer 91

The correct response is Option E. The most appropriate next step in management is observation. A Burrow triangle would not sufficiently address this deformity and is not necessary. Compression and staged advancement are not necessary, as the deformity resolves spontaneously. The temptation to excise should be resisted, as most of these ?dog ears? resolve over time. Photographs immediately after the procedure (left) and 5 months later (right) are shown. Excision would only increase the length-to-width ratio and compromise blood supply to the flap. If the contour abnormality is unacceptable to the patient after some time has passed, then excision at a later time can be performed. The need for this is exceedingly rare.

Answer 92

The correct response is Option D. All reverse flaps are based on a "retrograde flow" design, in which the blood flows into the artery and out of the vein, opposing normal physiology. In order for this to occur properly, either the valves of the peripheral veins must be incompetent or the flow of blood must circumvent the valves. The reverse radial forearm flap has small, intercommunicating veins that lie between the paired venae comitantes and act as shunts, bypassing the valves and allowing blood flow directly between the venae comitantes. Thus, retrograde flow is established, and a useful, viable vascularized flap is created. As long as the paired venae comitantes and intercommunicating veins remain intact, the reverse radial forearm flap can be used to cover large defects involving the dorsal aspect of the hand. Any mechanical separation of the venae comitantes during flap harvest will result in damage to the intercommunicating veins and lead to flap failure. In addition, an Allen's test should be performed preoperatively to demonstrate an adequate retrograde flow of blood from the ulnar artery through the distal artery. The cephalic vein originates at the radial aspect of the dorsal venous network and flows into the axillary vein. The basilic vein originates ulnarly within the dorsal venous network, joins with the median cubital vein, and ascends medial to the biceps tendon, perforating the deep fascia at the middle of the arm and then continuing as the axillary vein. The median vein of the forearm provides drainage for the superficial palmar venous plexus and ascends on the volar aspect of the forearm to drain into the basilic or median cubital vein. Because these veins and the accessory cephalic vein do not have interconnecting veins that allow for bypass of the valves, reverse flow is prohibited. The ulnar venae comitantes act in conjunction with the ulnar artery and thus are not involved in the drainage of the reverse radial forearm flap.

Answer 93

The correct response is Option D. The external oblique turnover muscle flap is not commonly used but has the potential to provide adequate coverage of large defects of the back that extend to the midline at the level of T10 to L4. The upper half of the flap is supplied by the 4th through 11th intercostal arteries, whereas the lower half is supplied by one or two vessels from the deep circumflex iliac artery (95%) or the iliolumbar artery (5%). The upper half has a strictly segmental blood and nerve supply, whereas the lower half has segmental innervation but derives its blood supply from one artery.

Answer 94

The correct response is Option B. The vascular supply of the lateral arm flap is from the posterior radial collateral artery, a terminal branch of the deep brachial artery. This artery communicates distally with the ulnar artery, allowing the flap to be raised in a distally based fashion, as it was for the patient in this item. For most adult patients, a 12 × 6-cm flap can be harvested and still allow for primary donor site closure. The major extremity vessels are not disturbed with the harvest of this flap. A groin flap would be difficult to mobilize sufficiently to reach the defect shown. It would also require leaving the arm attached to the torso for several weeks for vascular ingrowth prior to division and inset. The posterior interosseous artery flap is based on the communication between the anterior and posterior interosseous arteries just proximal to the distal radioulnar joint. Its pedicle can be used in a distally based fashion to allow for coverage of defects of the hand and wrist. It cannot reach to cover defects at the elbow. A radial forearm flap has two major disadvantages. It will remove a major vessel to a wrist and hand that is needed to heal a severe injury. It will also expose the radius fracture, requiring secondary flap reconstruction of the donor site. Split-thickness skin grafting is inappropriate to place over an exposed nerve, as sensitivity and pain would be expected to persist after healing. In addition, a skin graft would suffer secondary contraction, which would impair elbow extension.

Answer 95

The correct response is Option C. The photograph illustrates the markings for a reverse posterior interosseous artery (PIA) flap. The reverse PIA flap is a thin, pliable fasciocutaneous flap that can provide reliable coverage of soft-tissue defects involving the dorsal hand, metacarpophalangeal joints, and first web space. Some surgeons report success using this flap for coverage of palmar wounds and soft-tissue injuries of the thumb as well. Perfusion of the flap is based on retrograde flow through the posterior interosseous artery, which sends septocutaneous perforators to the overlying skin. The axis of the flap can be marked corresponding to a line between the lateral epicondyle and the radial aspect of the ulnar styloid. The location of the posterior interosseous artery pedicle is between the extensor digiti minimi and the extensor carpi ulnaris. Retrograde perfusion through the flap relies on an intact communication of the PIA with the dorsal branch of the anterior interosseous artery, which is present in nearly all cases. This anastomosis is located 2 cm proximal to the radial aspect of the ulnar styloid; therefore, it corresponds to the pivot point of the flap. One of the advantages of this flap is that it does not require sacrifice of a major arterial source of blood to the hand. The other responses do not correctly describe the location of the PIA. Of note, the interval between the brachioradialis and the flexor carpi radialis represents the location of the radial artery fasciocutaneous flap pedicle. Reference(s) 1. Acharya AM, Bhat AK, Bhaskaranand K. The reverse posterior interosseous artery flap: technical considerations in raising an easier and more reliable flap. J Hand Surg Am. 2012;37(3):575-582. 2. Gavaskar AS. Posterior interosseous artery flap for resurfacing posttraumatic soft tissue defects of the hand. Hand (N Y). 2010;5(4):397-402. 3. Wang JQ, Cai QQ, Yao WT, Gao ST, Wang X, Zhang P. Reverse posterior interosseous artery flap for reconstruction of the wrist and hand after sarcoma resection. Orthop Surg. 2013;5(4):250-254.

Answer 96

The correct response is Option E. The transverse cervical artery is the main pedicle to the trapezius muscle flap (type II muscle), which is particularly suitable for high cervical defects since the paraspinous muscles are of limited size and mobility at this level. The main pedicle of the trapezius flap enters the deep aspect of the muscle approximately 8 cm from the midline at the level of C7. Following identification of the main pedicle, the lateral aspect of the muscle is divided to permit transposition into the defect. Postoperative wound complications following spinal procedures approach 40% in high-risk patients. Thus, combined reconstructive approaches with orthopedic surgery and neurosurgery are common for management of these complex soft-tissue defects. Key management principles include timely debridement, bony fixation, and dead space obliteration. Therefore, muscle flaps are particularly suitable for reconstruction. A branch of the occipital artery is the dominant pedicle to the sternocleidomastoid flap, which is not a suitable reconstructive option for coverage of a posterior cervical defect. The circumflex scapular artery is the dominant pedicle to the scapular/parascapular fasciocutaneous (not muscle) flaps. The thoracoacromial artery is the dominant pedicle to the pectoralis major muscle (type V muscle). The thoracodorsal artery is the dominant pedicle to the latissimus dorsi muscle (type V muscle).

Answer 97

The correct response is Option C. The anterolateral thigh flap (ATL) is most frequently used as a free flap. However, it is an extremely reliable and versatile pedicled flap which can be used to reconstruct a variety of lower abdominal, perineal, and pelvic defects. Proximally based ATL flaps are based on flow from the descending branch of the lateral femoral circumflex artery. The descending branch runs between the vastus lateralis laterally and the rectus femoris medially. The perforators from this vessel run through the vastus lateralis to supply the overlying skin. Perforators usually penetrate the anterior aspect of the vastus lateralis. In less than 15% of cases, the perforators run in the septum between the vastus lateralis and the rectus femoris, and in this case, no intramuscular dissection is required. The medial femoral circumflex is the other main branch of the profunda femoris artery. It divides into the ascending superficial, deep, and acetabular branches and supplies the adductor brevis and magnus as well as the femoral neck. The lateral femoral circumflex divides into ascending, descending, and transverse branches. The ascending or transverse branch and its perforators supplies the tensor fascia lata muscle, and the descending branch supplies the rectus femoris. Its perforators supply the vastus lateralis and its overlying skin.

Answer 98

The correct response is Option F. Random pattern flaps are generally classified based on the primary motion of the flap. There are three basic types of tissue movement: transposition, advancement, and rotation. Transposition flaps incorporate noncontiguous skin into a defect by lifting the flap over normal skin for inset into a defect. Advancement flaps recruit adjacent tissue to close a defect via soft-tissue movement in a linear direction. Rotation flaps move adjacent tissue around an axis to close a defect, rotating soft tissue into the defect. Advancement and rotation flaps recruit adjacent lax tissue and move in either a linear or arced motion (respectively) to fill the defect. Transposition flaps recruit noncontiguous tissue, which is lifted over intact soft tissue and placed into the defect. Random pattern flaps lack a defined named arterial vascular supply. Because of their lack of an axial vascular supply, they are subject to dimensional restrictions. In general, they are designed to not exceed a length:width ratio of 2:1. An axial pattern flap is a single pedicled flap that has an anatomically named arterial blood supply running along its long axis. Because of the presence of a named arterial blood supply, axial pattern flaps are not subject to the length:width ratio restrictions that apply to random pattern flaps.

Answer 99

The correct response is Option C. In this patient who has exposure of the tendons and loss of paratenon after sustaining a wrist injury, the most appropriate management is coverage of the defect using a free lateral arm flap. This is a pliable fasciocutaneous flap that will provide durable coverage of this patient's defect with optimal cosmetic results and minimal donor site morbidity. Its good gliding surface will permit tendon gliding without tethering. If tethering were to occur subsequently, a secondary tenolysis could be easily performed underneath this thin flap. Dressing changes and healing by second intention are not appropriate in a patient with exposed tendons because tendon adhesions and/or dessication will result. In the same way, the defect should not be covered with a split-thickness skin graft, which will not take when placed directly on top of exposed tendon. Coverage with a free rectus abdominis flap will be bulky and can result in tethering. Secondary tenolysis will be difficult under this flap. The reverse radial forearm flap has been linked to the development of hand ischemia in patients who demonstrate radial dominance on Allen's testing.

Answer 100

The correct response is Option A. Z-plasty is a fundamental and common reconstructive technique used to elongate scars or contractures, narrow scars, rearrange tissues into relaxed skin tension lines, camouflage scars, or releasing tension. This is a form of rotation and advancement whereby a central limb of the Z-plasty is drawn parallel to the line of maximal tension, and subsequent limbs are drawn anywhere from 30 to 90 degrees from this. Wider angles give greater scar elongation at the expense of greater transverse tension. In this scenario, the line of maximum tension is longitudinal, creating an extension deformity. Maximal contracture release will occur with a central limb of the Z-plasty drawn longitudinally.

Answer 101

The correct response is Option C. The pedicle to the anterolateral thigh flap is the descending branch of the lateral femoral circumflex artery. The anterolateral thigh flap is a fasciocutaneous flap that has gained in popularity. This flap is capable of providing pliable tissue with a fascia to allow for tendon gliding. The flap has a large skin territory and does not require the sacrifice of a major vessel. The flap is based on perforators from the descending branch of the lateral femoral circumflex artery, which arises from the profunda femoris artery. The artery travels between the vastus lateralis and rectus femoris muscles and may travel in the septum or within the substance of the muscles. The flap is centered on the axis between the anterior superior iliac spine and the superior lateral border of the patella. Perforators to the anterolateral thigh flap can be variable, but the majority lies within 3 cm of a circle centered along the midpoint of that line. The ascending branch of the lateral femoral circumflex artery forms the pedicle for the tensor fascia lata flap. The ascending branch of the medial femoral circumflex artery forms the pedicle for the gracilis muscle flap. The descending branch of the medial femoral circumflex artery supplies the adductor muscles.

Answer 102

Correct answer is option A. When raising a radial forearm osteofasciocutaneous flap, cortical bone should be harvested from the radial aspect of the radius between the brachioradialis and pronator teres muscle insertions. A cuff of the flexor pollicis longus to the radius is maintained to preserve the periosteal vessels. A small cuff of periosteum is maintained on both sides of the radial vessels. All of the other optional donor sites are anatomically not appropriate. A segment up to 10cm in length and up to 40% of the cross sectional area of the radius may be harvested. The superficial branch of the radial nerve, running adjacent to the brachioradialis, is at risk and is sometimes sacrificed. https://emedicine.medscape.com/article/881055-overview?form=fpf&scode=msp&st=fpf&socialSite=google&icd=login_success_email_match_fpf#a5

Answer 103

Correct answer is option B. The Moberg flap is the most effective intervention for thumb tip defects of 1.5 cm or smaller. Some of the tactics that have been described to facilitate distal advancement of the flap include flexion of the thumb interphalangeal crease, extension of the lateral incisions proximal to the metaphalangeal crease, and islandization of the flap by releasing the skin at the base of the flap and skin grafting the donor wound. The cross-finger flap can be used for the thumb but is best suited for fingers of younger patients because of the risk of flexion contractures when used in older patients. Secondary healing is inappropriate in the case described because of the large size of the wound. Skin grafting is not appropriate for the patient described because bone is exposed. The thenar flap is harvested from the thumb and, therefore, is not used to reconstruct the thumb.

Answer 104

The correct response is Option D. The transverse cervical artery, which provides the primary vascular supply to the trapezius flap, is typically divided during an ipsilateral radical neck dissection. Therefore, the trapezius flap cannot be used for coverage of a defect in a patient who has undergone an ipsilateral radical neck dissection because its primarily vascular supply is presumed hes. The anterior branch then courses toward the shoulder, while the posterior branch courses beneath the central portion of the trapezius along its main axis, continuing to supply blood to this flat, triangularly shaped type II muscle. The occipital artery is a secondary source of vascularity for the trapezius muscle flap. However, in looking at the specific location and depth of this patient's defect, it appears that the portion of the muscle supplied by the occipital artery has been resected. The medial edge of the trapezius flap also receives some blood from posterior thoracic intercostal perforators along the medial edge of the flap. Because carotid endarterectomy is performed at or close to the bifurcation of the common carotid artery, it does not disrupt the thyrocervical trunk. The circumflex scapular vessels and vertebral arteries are not involved in supplying vascularity to the trapezius flap.

Answer 105

The correct response is Option B. The skin paddle of the free fibula flap receives its vascular supply from the peroneal, posterior tibial vessels, or from both. While a majority (95.8%) of the skin paddles receive their blood supply from the peroneal septocutaneous perforators, a few receive vascular contribution from both peroneal and posterior tibial systems, a few from only the posterior tibial system, and finally, a few from the popliteal artery. The anterior tibial and sural arteries do not typically contribute to the skin paddle of the free fibula graft.

Answer 106

The correct response is Option B. The best option to achieve wound closure in this patient is an ipsilateral latissimus dorsi myocutaneous flap. For chronic wounds in an irradiated field, the best option is debridement followed by transfer of healthy, nonirradiated tissue. Negative pressure wound therapy is likely to result in a recurrent chronic wound, albeit a clean one. Split-thickness skin graft would be inappropriate in an irradiated wound bed with exposed bone. Autologous fat grafting can help improve the quality of irradiated tissues in the absence of a wound, and some studies have shown promise in the treatment of superficial radiation ulcers; however, this patient has necrotic rib, and following debridement the wound will be deep and large. Although wound management and fat grafting have been shown to promote healing in isolated cases, this approach is not yet an accepted standard of care. Adjacent tissue transfer will employ irradiated tissue, and is thus prone to necrosis, wound breakdown, and recurrent chronic wound formation. A free flap could be an option, but a forearm flap would not have the volume required for the expected defect. In addition, a free flap is more morbid than a local pedicled flap in this elderly patient.

Answer 107

The correct response is Option D. The Mathes and Nahai classification of muscle flaps is based on vascular supply. Type III muscles have two dominant pedicles. The rectus abdominis muscle is supplied by both the superior and inferior deep epigastric vessels. The superior epigastric pedicle is an extension of the internal mammary circulation and allows transposition of the rectus muscle to the chest for breast and thoracic reconstruction. Pedicle flaps based on the inferior circulation are useful for pelvic and abdominal reconstruction. If one end of the muscle is in the zone of injury and the other side is spared, then a portion of the muscle could still be available for flap transfer. The gastrocnemius muscle flap is an example of a type I flap, having a single dominant circulation. Injury to the upper posterior calf would preclude safe use as a flap. Both the latissimus and pectoralis major muscles are type V, containing both a dominant pedicle as well as a group of smaller, equally sized segmental vessels. These muscles may be elevated as flaps based on either the dominant circulation or on the group of segmental vessels, and therefore, also provide a degree of versatility. The sartorius muscle is classified as type IV, having only a segmental circulation of multiple pedicles of equal size rather a dominant pedicle. The sartorius muscle is useful for coverage of the femoral sheath after a vascular surgical wound dehiscence with exposed prosthetic graft. Type II muscle flaps have both a dominant pedicle and a minor circulation. The minor vessels are typically divided to allow use of a flap based on the dominant pedicle. Examples include the gracilis and biceps femoris muscles.

Answer 108

The correct response is Option B. The posterior radial collateral artery is a branch from the profunda brachial artery, which is off the brachial artery. A second branch is the anterior radial collateral artery but this is variable and of small caliber so does not contribute to the vascular supply. The posterior radial collateral artery interconnects with the radial recurrent artery off the radial artery. This will allow for reverse pedicle design. The middle or medial collateral artery is a branch off the posterior radial collateral artery in 61.5% and off the profunda brachial artery in 38.5%. It can be used as an elongated lateral flap by converting a Y to a V. The radial, ulnar, and posterior ulnar collateral arteries are not appropriate. The radial artery supplies the radial forearm flap, a fasciocutaneous flap. The ulnar artery supplies a fasciocutaneous flap as well. The posterior ulnar recurrent artery supplies the flexor carpi ulnaris flap, which is a muscle or musculocutaneous flap.

Answer 109

The correct answer is B) Keystone design perforator island flap Explanation: The keystone design perforator island flap is an ideal option for reconstructing large soft tissue defects, especially when there is no need for microsurgical techniques. The flap is designed to use random fasciocutaneous and musculocutaneous perforators, with an advancement technique that minimizes tension and improves closure. The design allows for excellent aesthetic coverage, especially in areas like the medial thigh, and reduces the need for skin grafting. The inclusion of V-Y advancement flaps at the poles further facilitates closure and minimizes tension. Rationale for other options: • A) Free anterolateral thigh flap: While this is a reliable option, it involves microsurgery and a higher donor site morbidity, which could be avoided with the keystone flap in this case. • C) Rectus abdominis myocutaneous flap: This flap involves harvesting a muscle, which increases morbidity, especially for a defect in the thigh, where a fasciocutaneous flap would be preferable. • D) Medial gastrocnemius flap: This flap would not be suitable for a defect on the medial thigh as it cannot reach the area effectively, and it involves sacrificing muscle. • E) Latissimus dorsi myocutaneous flap: Although effective, this flap requires muscle harvesting and a more invasive approach, making it less ideal compared to the keystone flap for this specific defect. Key considerations for flap design: The keystone design perforator island flap allows for a well-vascularized coverage of large defects using locally available tissue, preserving the integrity of the surrounding area. The proper design and execution of the flap, along with techniques like V-Y advancement and deep fascial release, optimize the success of the reconstruction while minimizing donor site morbidity. References: 1. Weinberg M, Heiman AJ, DeSanti R, Lanni MA, Kouwenberg EV, Patel A. Outcomes of the keystone island perforator flap: a systematic review. J Reconstr Microsurg. 2022;38(9):727-733. doi:10.1055/s-0042-1745744 2. Gómez OJ, Barón OI, Peñarredonda ML. Keystone flap: overcoming paradigms. Plast Reconstr Surg Glob Open. 2019;7(3):e2126. doi:10.1097/GOX.0000000000002126 3. Khouri JS, Egeland BM, Daily SD, et al. The keystone island flap: use in large defects of the trunk and extremities in soft-tissue reconstruction. Plast Reconstr Surg. 2011;127(3):1212-1221. doi:10.1097/PRS.0b013e318205f36f 4. Behan FC. The keystone design perforator island flap in reconstructive surgery. ANZ J Surg. 2003;73(3):112-120. doi:10.1046/j.1445-2197.2003.02638.x

Answer 110

The correct response is Option D. The rectus abdominis muscle has several sources of blood supply, including the superior and inferior epigastrics and intercostal vessels. For the purpose of chest wall reconstruction, the rectus muscle is pedicled upon its superior blood supply, the superior epigastric vessels, which itself is a continuation of the internal mammary vessels. Since the internal mammaries have been used on both sides for the purpose of coronary artery bypass grafting, the blood supply to the rectus has been compromised. Although it is possible to raise the rectus muscle on only the eighth intercostal blood vessel, this method is less reliable and less likely to be sufficient to sustain the entire rectus muscle, making it prone to flap necrosis.

Answer 111

The correct response is Option C. The rectus abdominis muscle is a Mathes and Nahai classification Type III muscle. The Mathes and Nahai classification of the vascular anatomy of muscles represents an important description in reconstructive surgery. Type I muscles have one vascular pedicle and include the gastrocnemius, rectus femoris, and tensor fascia lata. Type II muscles have a dominant and minor pedicle and include the abductor digiti minimi, abductor hallucis, biceps femoris, flexor digitorum brevis, gracilis, peroneus longus, peroneus brevis, platysma, semitendinosus, soleus, sternocleidomastoid, temporalis, trapezius, and vastus lateralis. Type III muscles have two dominant pedicles and include the gluteus maximus, rectus abdominis, serratus anterior, and semimembranosus. Type IV muscles have multiple segmental pedicles and include the extensor digitorum longus, extensor hallucis longus, flexor digitorum longus, flexor hallucis longus, sartorius, and tibialis anterior. Type V muscles have one dominant and secondary segmental pedicles and include the pectoralis major and latissimus dorsi.

Answer 112

The correct response is Option B. The most likely expected increase in scar length is 50%. A Z-plasty is a technique using two triangular flaps which are interdigitated, producing a gain in length of the central limb placed along the line of contracture. The angles of the Z-plasty range from 30 to 90 degrees. The wider the angles, the greater the lengthening. A 30-degree angle is equal to a 25% increase in length, a 45-degree angle is equal to a 50% increase in length, a 75-degree angle is equal to a 100% increase in length, and a 90-degree angle is equal to a 120% increase in length. The most commonly used angle is 60 degrees, giving a 75% increase in length. This angle is optimal because angles less than 60 degrees may not provide enough lengthening, and angles greater than 60 degrees can produce significant tension inhibiting flap transposition.

Answer 113

The correct response is Option C. The peroneal artery is adjacent to the fibula. It arises from the tibioperoneal trunk, immediately distal to the takeoff of the anterior tibial artery. It perforates the interosseous membrane. The peroneal artery also gives perforators to the skin of the lower leg. The length of the pedicle is usually short, but can be increased substantially by dissecting the peroneal artery from the fibula and using the distal bone for reconstruction. The popiteal artery is proximal to the other arteries mentioned. After crossing the knee, it branches into the anterior and posterior tibial arteries. The posterior tibial artery then gives off the peroneal artery.

Answer 114

The correct response is Option B. Medicinal leeches (Hirudo medicinalis) have been used as an aid to salvage congested free flaps. The incidence of infection associated with leech therapy reported in the literature ranges from 2.4% to 20%. The severity of infections ranges from cellulitis to tissue necrosis, abscess, and septicemia. Delayed infection from colonized necrotic tissue can also occur. The organism most often responsible is Aeromonas hydrophila, a gram-negative anaerobe that is part of the intestinal resident flora of the leech. Resistance to penicillins and first-generation cephalosporins is not uncommon because of their production of beta-lactamase enzymes. Resistance to trimethoprim and sulfamethoxazole, tetracycline, imipenem, and even gentamicin has also been reported. Susceptibility to fluoroquinolones such as ciprofloxacin continues to be observed. Prophylactic antibiotics with a fluoroquinolone and aminoglycoside are recommended, and therapy should be continued until any open wound or necrotic tissue has completely healed.

Answer 115

Correct answer: C. Contracture of the flexor hallucis longus muscle. When harvesting a free fibula osteocutaneous flap, the flexor hallucis longus muscle is separated from the fibula bone and preserved. However, because its attachments to the fibula have been divided, contracture of the flexor hallucis longus muscle can develop, resulting in a claw toe over time. If the flexor hallucis longus muscle is harvested with the flap, the patient will be unable to flex the great toe immediately postoperatively. The extensor hallucis longus, peroneus brevis, peroneus longus, and tibialis posterior muscles are all dissected away from the fibula and could be injured during the dissection. However, this would not result in a claw toe. References: 1. Ling XF, Peng X. What is the price to pay for a free fibula flap? A systematic review of donor-site morbidity following free fibula flap surgery. Plast Reconstr Surg. 2012;129(3):657-674. doi:10.1097/PRS.0b013e3182402d9a 2. Ni Y, Zhang X, Zhang Z, et al. Assessment of fibula flap with flexor hallucis longus’s effect on head & neck tumor patients’ quality of life and function of donor site. Oral Oncol. 2020;100:104489. doi:10.1016/j.oraloncology.2019.104489

Answer 116

Correct Answer: D. Hyoglossus muscle Rationale: The submental flap is an axial-patterned flap based on the submental artery, a reliable branch of the facial artery. The submental artery runs between the horizontal ramus of the mandible and the submandibular gland, supplying the surrounding structures. The muscles that can be included with the flap are the mylohyoid, platysma, and the anterior belly of the digastric muscle. The submental artery also supplies the submandibular gland, mandible, and cutaneous perforating vessels through the platysma. However, the hyoglossus muscle is not included in this flap or the same anatomic area, as it receives its blood supply from the lingual artery, specifically its sublingual branch. The genioglossus, hyoglossus, and stylohyoid muscles are not part of the submental flap's vascular territory. References: Bertrand B, Honeyman CS, Emparanza A, et al. Twenty-five years of experience with the submental flap in facial reconstruction: evolution and technical refinements following 311 cases in Europe and Africa. Plast Reconstr Surg. 2019;143(6):1747-1758. doi:10.1097/PRS.0000000000005678 Honeyman C, Cebron U, Bradley D, et al. Increasing the reach of the submental artery island flap using the Y-V pedicle lengthening technique: video and technical considerations. Plast Reconstr Surg. 2021;148(5):1121-1124. doi:10.1097/PRS.0000000000008486

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