Flaps 01-22, 24 Flashcards

Question

A 24-year-old man comes to the office because of an open wound and osteomyelitis of the right elbow after sustaining a fracture of the olecranon during a fall 1 month ago. Use of the lateral arm flap for coverage of the defect is planned. Which of the following is the arterial supply to the lateral arm flap? ## Footnote A) Medial collateral B) Posterior radial collateral C) Posterior ulnar collateral D) Radial E) Ulnar

Answer 1

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 2

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 3

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 4

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 5

The correct response is Option B. The deep circumflex iliac artery arises from the external iliac artery and is the blood supply to the iliac crest osteocutaneous flap. This flap can be harvested either as a bone-only or an osteocutaneous free flap. It is often used in hemimandibular reconstruction because the natural curvature of the iliac crest closely resembles the shape of the hemimandible. A portion of the internal oblique muscle, based on the ascending branch of the deep circumflex iliac artery, can also be included with this flap. The descending branch of the geniculate artery is the blood supply to the medial femoral condyle flap. The ascending branch of the lateral circumflex femoral artery is the blood supply to the tensor fascia lata flap. The peroneal artery is the blood supply to the fibula flap. The deep inferior epigastric artery is the blood supply to the rectus abdominis myocutaneous flap.

Answer 6

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 7

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 8

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 9

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 10

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 11

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 12

The correct response is Option D. The gracilis muscle is the workhorse for functional muscle transfer, and it has been successfully used to restore hand function in patients with severe Volkmann ischemic contracture. Innervation of the muscle is via a branch of the obturator nerve, which is composed of 2 to 3 fascicular bundles. The nerve length from its emergence from the obturator foramen to its insertion into the muscle averages 7.7 cm, and separation of the fascicular bundles can allow the muscle to be segmented. The other nerves listed do not innervate the gracilis muscle.

Answer 13

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 14

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 15

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 16

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 17

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 18

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 19

The correct response is Option B. The blood supply to the omental flap is through the right and left gastroepiploic arteries. Understanding the anatomy and blood supply to the omentum is crucial for success in omental flap transfer. The greater omentum is harvested from the transverse colon, as the short gastric vessels are ligated and the gastroepiploic vessels preserved. The omentum can be transposed to the chest through either an opening in the diaphragm or a fascial defect in the abdominal wall. The left gastric vessels arise from the celiac vessels and supply the lesser curvature of the stomach. The gastroduodenal artery arises from the celiac trunk and provides blood supply to the pylorus and proximal duodenum. One of the terminal branches of the gastroduodenal artery is the right gastroepiploic artery. The superior epigastric artery supplies the rectus abdominis muscle and is not intraperitoneal. The superior mesenteric artery arises from the aorta below the celiac trunk and supplies the lower duodenum through the transverse colon; it does not carry the blood supply necessary for design of an omental flap.

Answer 20

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 21

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 22

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 23

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 24

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 25

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 26

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 27

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 28

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 29

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 30

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 31

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 32

The correct response is Option E. The transverse cervical artery is the blood supply to the trapezius flap which is used to reconstruct the defect described. The circumflex scapular artery is the blood supply to the scapular/parascapular flap. This artery has a length of approximately 6 to 7 cm and does not have the arc of rotation to reach a posterior neck defect. The deep temporal artery is the blood supply of the temporalis muscle. The arc of rotation of this muscle does not enable repair of posterior neck defects. The internal carotid artery does not give rise to branches that supply the muscles of the neck/back that may be useful for reconstruction of this defect. The superficial temporal artery is the blood supply of the superficial temporal fascia. This flap is quite thin with a limited reach and would not be appropriate for reconstruction of an extensive resection that includes skin, subcutaneous tissues, and muscle as shown.

Answer 33

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 34

The correct response is Option B. The temporoparietal fascial flap is supplied by the superficial temporal artery. This thin fascial free flap is useful in reconstruction of traumatic injuries that are not amenable to reconstruction with a skin graft alone. This flap is particularly useful in reconstruction of gliding surfaces with denuded tendons or exposed joints. The posterior auricular artery is a branch of the external carotid artery and supplies the posterior ear. The superior thyroid artery arises from the external carotid artery and supplies the thyroid gland. The supratrochlear artery supplies the forehead and scalp. The transverse facial artery is a branch of the superficial temporal artery and supplies the parotid gland. None of these vessels is involved in the vascular supply of the temporoparietal fascial flap.

Answer 35

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 36

The correct response is Option B. The clinical image shown depicts a radial forearm flap. The vascular pedicle of the radial forearm flap is the radial artery that is a branch of the brachial artery. Proximally, the radial artery runs deep to the brachioradialis muscle and it passes distally between the bellies of the brachioradialis and flexor carpi radialis. The radial forearm flap cutaneous paddle is perfused by septocutaneous perforators from the radial artery. The other options are incorrect because the vascular pedicle does not pass between those muscles. References

Answer 37

The correct response is Option A. Shotgun blasts at close range can create a devastating pattern of injury. X-ray study shows a heavily comminuted ulna fracture. The scenario also involves tendon, vascular, and nerve injury. In choosing the appropriate coverage for the wound described, the surgeon will need to consider the protection of exposed structures, the ability to rehabilitate the extremity, and the possible need for future surgery on the arm. A free tissue transfer will provide viable, full-thickness tissue from a nontraumatized area to cover the wound. Many donor sites are available, including fasciocutaneous flaps such as the anterolateral thigh flap, as well as muscle flaps. Some authors advocate fasciocutaneous flaps over muscle flaps with the rationale that the fat on the deep surface of the flap will better allow glide of tendons and nerves deep to it; in addition, a fasciocutaneous flap, once healed, can be incised like normal skin for any future surgery that might be necessary in the patient’s arm. A photograph is shown. Skin grafting, whether split-thickness or full-thickness, carries several liabilities. Both types of grafts provide skin but no subcutaneous tissue. In addition, both heal by adhering to the wound bed. Because the patient described has exposed tendon in the wound bed, skin grafting would likely cause significant tendon adhesions and thus impaired mobility. In addition, adhesion of the skin graft to a nerve, particularly a repaired nerve, carries a risk of chronic pain and nerve dysfunction. A pedicled groin flap can provide thin, pliable, full-thickness tissue to cover defects of the forearm. However, the flap is done as a two-staged procedure, with the arm tethered to the groin for 2 to 3 weeks to allow vascular ingrowth. In the patient described, having the arm dependent for that period of time would significantly worsen edema and compromise the ability to begin rehabilitation of the extremity. A reversed lateral arm flap provides full-thickness soft-tissue coverage for defects about the elbow. Its harvest does not require sacrifice of a major artery to the hand. The lateral arm flap would not be able to reach the distal limit of the wound described. In addition, the lateral arm flap donor site can be closed primarily for flaps up to 12 × 6 cm, which is significantly smaller than the wound in the patient described.

Answer 38

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 39

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 40

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 41

The correct response is Option D. The blood supply for the fibula flap skin paddle used for reconstruction arises from septocutaneous perforators from the peroneal artery that traverse the posterior intermuscular septum. The position of these vessels can be marked before the procedure with a pencil Doppler probe. In the majority of cases, the blood supply to the fibula flap skin paddle is reliable for microsurgical transfer. The skin flap also has blood supply arising from musculocutaneus perforators originating from the soleus and gastrocnemius muscles; however, these vessels are, in most cases, ligated because their dissection is tedious, and they often arise from the posterior tibial artery. The anterior and posterior tibialis muscles do not provide blood supply to the fibula flap skin paddle.

Answer 42

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 43

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 44

The correct response is Option E. The most likely dominant arterial supply to the reverse lateral arm flap is the radial recurrent artery. It is a branch of the radial artery and arises in the cubital fossa. It anastomoses with the posterior radial collateral artery just above the lateral epicondyle and medial to the brachioradialis within the lateral intermuscular septum. This pedicled flap can be used to cover defects of the elbow and requires retrograde flow through the posterior radial collateral artery via the radial recurrent artery. Prior trauma or radical surgery around the elbow and severe peripheral vascular disease warrant confirmation of presence or patency of the pedicle via Doppler ultrasonography or angiography. After rotating this flap more than 180 degrees, venous insufficiency may result and require microanastomosis of a superficial vein in the flap to a receptor vein in the defect to augment outflow. The posterior radial collateral artery is the dominant inflow for the standard lateral arm flap. The inferior cubital artery is the dominant inflow and the musculocutaneous perforating branches from the brachioradialis muscle are the minor pedicles for the antecubital flap. The artery to the biceps muscle supplies the medial arm flap.

Answer 45

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 46

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 47

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 48

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 49

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 50

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 51

The correct response is Option C. The gluteal musculocutaneous flap is a Type III flap, meaning it has two dominant pedicles (the superior and inferior gluteal arteries). These arteries are separated by the piriformis muscle and are sourced to the internal iliac system. A Type I flap has a single dominant pedicle (ie, tensor fascia lata). A Type II flap has dominant and minor pedicle(s) (ie, gracilis). A Type IV flap has multiple segmental pedicles (ie, sartorius). A Type V flap has a dominant pedicle and secondary segmental pedicles (ie, latissimus).

Answer 52

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 53

The correct response is Option D. The anterolateral thigh flap is located over the lateral third of the thigh, between the borders of the rectus femoris and vastus lateralis muscle. Its blood supply comes from perforating branches of the lateral circumflex femoral artery and its venae comitantes. These vessels arise from the profunda femoris artery and vein. By utilizing the transverse branch of the lateral femoral circumflex artery and venae comitantes and their musculocutaneous perforators, the vastus lateralis muscle can be harvested with the anterolateral thigh flap. This muscle can be used for added bulk in the flap. The anterolateral thigh flap may also be harvested with the tensor fascia lata muscle. This flap may also be used as a functional muscle transfer.

Answer 54

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 55

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 56

The correct response 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 57

The correct response is Option E. The medial and lateral sural arteries supply circulation to the gastrocnemius muscle, which, when released and rotated proximally, provides the best coverage for complex knee wounds. The gastrocnemius muscle may be harvested with overlying skin or may be skin-grafted. The medial circumflex femoral artery and profunda femoris vessels supply the gracilis muscle, which provides coverage for medial thigh and groin defects. It cannot be rotated distally. The posterior tibial artery provides some blood supply to the soleus muscle, which is the preferred muscle coverage to wounds to the middle one third of the lower extremity. The posterior tibial, peroneal, and anterior tibial arteries provide perforators for fasciocutaneous flaps in the lower extremity, which are limited in their applicability and are too distal for coverage of the wound.

Answer 58

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 59

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 60

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 61

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 62

The correct response 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 63

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 64

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 65

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 66

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 67

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 68

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 69

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 70

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 71

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 72

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 73

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 74

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 75

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 76

The correct response is Option A. The deep inferior epigastric artery and vein arise from the external iliac artery at a point just proximal to where the artery passes beneath the inguinal ligament. The internal mammary vessels provide the regional source for the superior epigastric artery. The femoral, internal iliac, and superficial inferior epigastric arteries are not source vessels for the deep inferior epigastric artery and vein. The femoral artery originates as the external iliac vessels exit from the inguinal ligament. The internal iliac artery supplies blood to structures within the pelvis.

Answer 77

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 78

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 79

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 80

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 81

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 82

The correct response is Option C. The free groin flap is typically an axially patterned flap that receives its vascularity by the superficial circumflex iliac artery, which arises from the common or superficial femoral artery and then traverses laterally, parallel to the inguinal ligament, typically 2 to 3 cm inferior to the ligament. Although it provides excellent thin soft-tissue coverage of cutaneous defects and is associated with minimal donor site morbidity, especially in women, its use is limited by potential variations in vascular anatomy, as shown in the illustration below. In 45% to 50% of persons the superficial circumflex iliac artery and superficial inferior epigastric artery arise from a common trunk, as shown in the figure on the left. In contrast, 40% to 45% of persons have a superficial circumflex iliac artery and superficial inferior epigastric artery that arise from separate origins, as shown in the figure on the right. The middle figure demonstrates a large superficial circumflex iliac artery without a superficial inferior epigastric artery, which is present in 10% to 15% of persons. In patients being considered for reconstructive procedures using the free groin flap, vascular anatomy can be determined preoperatively using Doppler ultrasonography. In addition to its usefulness in coverage of cutaneous defects, as shown in the postoperative photograph below, the free groin flap can also be deepithelialized and transferred as soft-tissue fill in patients with Romberg's disease or hemifacial microsomia.

Answer 83

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, resulting in an increase in the length of the central limb and a change in 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 the scars within the lines of minimal tension. The actual amount of scar lengthening correlates directly with the angle and length of the flap limbs, as demonstrated in the table above.

Answer 84

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 85

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 86

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 87

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 88

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 89

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 90

The correct response is Option B. Because the lateral arm flap provides both vascularized bone and a sensate skin paddle, it is best used for reconstruction of this patient's defect involving the floor of the mouth. Vascularity and skin sensibility are provided by the radial collateral artery and posterior brachial cutaneous nerve (C5-6), respectively. As much as 7 cm \* 12 cm of skin can be elevated with the flap; in addition, because of its periosteal attachments, as much as one-third of the posterior lateral humerus (or 10 cm to 15 cm in length and 1 cm to 1.5 cm in diameter) can be harvested. 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. The parascapular flap is based on the circumflex scapular artery. Advantages of this flap include multiple skin paddles, a large segment of bone, and a high degree of independent motion between the skin and bone segments. The serratus anterior and/or latissimus dorsi muscles can be included with the flap to reconstruct complex defects. However, the skin paddles of this flap are also bulky and lack a cutaneous sensory nerve. The serratus anterior flap is extremely versatile. Skin, muscle, and an iliac bone graft can be included with this flap; its pedicle is long and has a large diameter. It can be harvested as a functional muscle flap with inclusion of the branches of the long thoracic nerve; however, the upper four to five muscle slips must be preserved in order to prevent winging of the scapula. This primary disadvantage of this flap is that any bone incorporated with it will be less substantial and have poor vascularization when compared with other osteocutaneous flaps. The skin component of this flap is also insensate.

Answer 91

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 92

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 93

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 94

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 95

The correct response is Option C. When the vastus lateralis flap is based on its dominant pedicle, the descending branch of the lateral femoral circumflex artery, it has an area of rotation that will provide vascularized coverage of the lower abdomen, groin, perineum, ischium, trochanter, and acetabular fossa. However, the flap must be reversed in order to rotate and provide coverage of knee defects. When used in this manner, the flap is then based on a branch of the lateral genicular artery, which is a minor distal pedicle. Because the risk for partial flap loss is greater, this flap is not often advocated for coverage of knee defects.

Answer 96

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 97

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 98

The correct response is Option B. Descending branch of the lateral femoral circumflex artery and hip flexion and knee extension represent the blood supply to and function of the rectus femoris muscle flap, one of the predictable, workhorse flaps for groin wound reconstruction. After supplying the rectus femoris muscle, the lateral femoral circumflex artery continues on to supply the anterolateral thigh flap. The rectus femoris muscle crosses both the hip joint and the knee joint, and as such functions to both flex the hip and extend the knee. The hamstring muscles, which are on the posterior thigh would not be an appropriate choice for groin wound reconstruction. The tensor fascia lata muscle is used for lateral hip wounds but not typically for groin wound reconstruction. The adductor longus muscle is not used in groin wound coverage. The sartorius muscle has already been used in this patient's previous surgery and it is therefore not available for this reconstruction. The sartorius muscle is preferred for smaller wounds and is often used for prophylactic coverage in complex groin cases.

Answer 99

The correct response is Option D. The term "propeller flap" was first used in 1991 by Hyakusoku et al to describe an adipocutaneous flap based on a central subcutaneous pedicle, with a shape resembling a propeller that was rotated 90 degrees. In modern parlance, a propeller flap is a skin or fasciocutaneous flap based on a perforator artery, often rotated 90 to 180 degrees to fill a local defect. Since perforator arteries occur in predictable locations and can be confirmed with a handheld Doppler examination, propeller flaps can be created as "freestyle" flaps based on perforator arteries to cover a variety of lower extremity wounds. Propeller flaps do not have a random blood supply and are not based on the subdermal plexus, and they are skin flaps, not muscle flaps.

Answer 100

The correct response is Option C. A submental flap is an axial-patterned flap based on the submental artery. It is commonly used for intraoral and cutaneous lower face indications. The submental artery is a reliable branch of the facial artery. The submental artery runs between the horizontal ramus of the mandible and the submandibular gland. It proceeds until it meets the anterior belly of the digastric muscle, where it branches to the submandibular gland, the mandible, the mylohyoid muscle, the anterior belly of the digastric muscle, and cutaneous perforating vessels through the platysma. The muscles that can be included with the flap include mylohyoid, platysma, and the anterior belly of the digastric. Additional bulk and size can be achieved with adding the mylohyoid and anterior digastric muscles. The submental artery is the largest of the cervical branches of the facial artery, given off just as that vessel leaves the submandibular gland; it runs forward on the mylohyoid muscle, just below the body of the mandible, and beneath the digastric muscle. It supplies the surrounding muscles and anastomoses with the sublingual artery and with the mylohyoid branch of the inferior alveolar artery. The anterior belly of the digastric muscle receives its arterial supply mainly from the submental artery of the facial artery, and the posterior belly of the digastric muscle receives its arterial supply from the posterior auricular and occipital arteries. The genioglossus receives blood supply from the sublingual branch of the lingual artery. Hyoglossus and stylohyoid muscles are not included in this flap or same anatomic area.

Answer 101

A Advanced rectal cancer continues to be frequently treated with abdominoperineal resection. Depending on the extent of the tumor, posterior vaginectomy may be necessary, thus resulting in a type IB vaginal defect. The surgical principles guiding reconstruction in these cases include vascularized tissue transfer for the purpose of providing stable skin coverage, reconstruction of the posterior mucosal defect, and pelvic dead space obliteration. Naturally, one should strive to accomplish these goals while keeping donor site morbidity to a minimum. Common reconstructive techniques include the vertical rectus abdominis myocutaneous (VRAM) flap, anterolateral thigh flap, or profunda artery perforator (PAP) flap. The patient's history of abdominoplasty precludes the use of a VRAM flap, while the history of bilateral medial thigh lift precludes the use of medial thigh flaps (ie, PAP flap, transverse upper gracilis flap, pudendal flap). Of the flaps listed, only the anterolateral thigh flap would be appropriate.

Answer 102

E The keystone design perforator island flap is a fasciocutaneous local flap useful for reconstruction of large defects without reliance on microsurgical techniques. The flap is shaped as an ellipse with the long axis adjacent to the long axis of the defect. The flap is based on randomly located fasciocutaneous and musculocutaneous vascular perforators. Advancement of the central portion of the flap allows the wound to be closed directly, with the line of maximum tension at the midline of the flap. At each end of the flap, V-Y advancement is used to exploit the mobility of the adjacent surrounding tissue to assist with flap closure with decreased tension. The need for skin grafting is minimized with proper design and execution of the keystone flap, with excellent aesthetic coverage of the defect with similar adjacent fasciocutaneous tissue. Four types of flaps were originally described by Dr. Behan: type I (direct closure), type II (with or without grafting), type III (employing a double island flap technique), and type IV (involving rotation and advancement with or without grafting). Undermining of the central advancement portion of the flap would damage the random fasciocutaneous and musculocutaneous perforating blood vessels essential for flap vascularity. Creation of V-Y flaps at the opposing poles of the flap assists with flap advancement with decreased tension by using surrounding tissue mobility. As the central flap is advanced, two regions of skin excess at the inner corners of the flap are often noted due to the defect excision and flap design. These skin excess regions can be safely excised to minimize standing cutaneous deformities at the time of closure. Sharp incision of the deep fascia along the flap margins is often necessary to fully mobilize and advance the flap without significant shear and tension forces. This a useful technique to optimize keystone flap success. Keystone flap standard design involves ensuring the height of the keystone is equal to the short axis of the defect ellipse and parallel to the maximal resulting tension vector. The keystone flap uses a 1:1 ratio for the width of the defect to the width of the flap.

Answer 103

A The scapular flap can be used as a pedicled flap to reconstruct the shoulder, the back of the neck, or the axilla. As a free flap, it can be harvested as a fasciocutaneous flap only or harvested with scapular bone. The blood supply of this flap is the circumflex scapular artery, which is a branch of the subscapular artery. The circumflex scapular artery anastomoses with the transverse scapular artery (suprascapular) as well as the dorsal scapular artery (transverse cervical).

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Flaps 01-22, 24 Flashcards

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