Flaps Flashcards
A 35-year-old man is brought to the emergency department with a 15-cm open wound on the left hip and thigh after he was involved in an accident while using machinery at a construction site. Much of the skin of the lateral thigh is injured, and exposed bone is noted over the trochanter of the hip. Wound coverage using an anterolateral thigh flap from the right side is planned. When the flap is harvested, which of the following muscles must be identified in order to preserve perforators to the flap?
A) Gracilis
B) Inferior gluteal
C) Sartorius
D) Tensor fascia lata
E) Vastus lateralis
The correct response is Option E.
The anterolateral thigh flap is a versatile coverage tool because of its wide skin island (up to 8 x 25 cm) and long, accessible pedicle (up to 7 cm). The blood supply originates from the lateral femoral circumflex artery descending branch, and sends perforating branches through the vastus lateralis and rectus femoris muscles, and occasionally through the intermuscular septum.
The inferior gluteal muscle, while a common muscle flap, is further posterior and proximal. The tensor fascia lata is more lateral to the anterolateral thigh flap zone, though it also has a blood supply from the lateral femoral circumflex system, as the vessel terminates in the tensor fascia lata. The sartorius is more medial and proximal and has a segmental circulation based on the femoral artery branches. The gracilis is more medially based, and is supplied by the medial femoral circumflex.
2018
A 40-year-old man sustains burns to 35% of his total body surface area, including the neck, chest, axillae, and upper extremities. After subsequent skin grafting, a right anterior axillary dome scar contracture develops. The patient is scheduled to undergo revision of the scar using Z-plasty. Which of the following lateral limb angles will result in a theoretical 75% gain in central limb length?
A) 30 degree
B) 45 degree
C) 60 degree
D) 75 degree
E) 90 degree
The correct response is Option C.
The traditional standard Z-plasty consists of at least three incisions of equal length (two limbs and one central incision) and two angles of equal degree. Ideally, the central incision runs parallel to the long axis of the scar, or the scar itself may be completely excised with the fusiform defect acting as the central incision.
The resultant subcutaneous triangular skin flaps are transposed with each other such that the new, central incision lies perpendicular to the original central incision. After closure, the scar is reoriented along the limb incisions, and the new central incision lies within relaxed skin tension lines. The length of the original scar also increases after a Z-plasty, which is a useful characteristic when a surgeon desires release of a scar contracture, as in this specific example. In general, as the central incision lengthens (given a constant angle), so does the resultant scar. Additionally, as the angles between the limbs increase (given a constant limb length), so does the resultant scar.
2018
A 63-year-old man has a full-thickness scalp defect following resection of a melanoma. Final pathology has confirmed clear margins. Which of the following criteria is an indication for coverage of the defect with a flap instead of a skin graft?
A) Alopecia of the surrounding skin
B) Exposed calvarium
C) Granulation tissue in the base of the wound
D) Intact pericranium
E) Posterior location
The correct response is Option B.
Exposed bone does not provide an adequately vascularized bed for skin graft take. Pericranium, in contrast, can support a skin graft. The presence of granulation tissue is a good sign that the wound bed is adequately vascularized for a skin graft to take. Surrounding alopecia decreases aesthetic concerns associated with reconstructive options that do not support hair growth. Defect location does not significantly affect the need for vascularized coverage.
2018
Which of the following vessels runs within the pedicle of the reverse sural artery flap and serves as primary venous drainage?
A) Femoral
B) Greater saphenous
C) Lesser saphenous
D) Popliteal
E) Posterior tibial
The correct response is Option C.
The reverse superficial sural artery flap (RSSAF) is a distally based fasciocutaneous or adipofascial flap that is increasingly being used for coverage of defects that involve the distal third of the leg, ankle, and foot. First described by Donski and Fogdestam and later championed by Masquelet et al, RSSAF has become a popular option for these difficult wounds. The description of the RSSAF (Masquelet flap) has revolutionized the osteoplastic armamentarium of surgeons not conversant with microvascular free flaps. The reliability of septocutaneous perforators has been well documented. Hence, raising a flap based on this reliable anastomosis of peroneal artery and median sural artery, along with the sural nerve and lesser (short) saphenous vein has been described to be successful.
A significant advantage of this flap is that it does not require sacrifice of a major artery to the lower limb. Touted for its ease of dissection, the RSSAF is often reputed to have a favorable complication profile as evidenced by a recent meta-analysis that found 82% of flaps heal without any flap-related complications. The main complications include venous congestion of the flap requiring delay or leech therapy in some higher-risk patients.
The greater saphenous vein runs proximal and medial to the lesser saphenous vein, and it drains the medial and anteromedial portion of the lower leg.
The popliteal vein drains the lesser (short) saphenous vein, and it is therefore not the primary drainage of the reverse sural flap. The anterior and posterior tibial veins are the deep venous drainage of the lower leg and do not drain the RSSAF.
The femoral vein is the deep venous drainage system in the upper leg.
2018
A 75-year-old man who had femoral-popliteal bypass surgery 2 weeks ago has an infection in the proximal groin. A muscle flap to fill the dead space is planned. Which of the following muscle flap options has a type IV Mathes-Nahai (multiple segmental vascular pedicles) vascular anatomy?
A) Gracilis
B) Rectus abdominis
C) Rectus femoris
D) Sartorius
E) Vastus medialis
The correct response is Option D.
The sartorius muscle classically has a type IV Mathes-Nahai vascular anatomy, which may limit its arc of rotation. In a recent study, even though the sartorius muscle has multiple segmental pedicles, there tend to be codominant superior and inferior pedicles that could possibly allow for the majority of the muscle to be raised on either the superior or inferior dominant pedicle.
Mathes-Nahai vascular anatomy classification for muscle flaps:
I – Single dominant vascular pedicle
II – Single dominant vascular pedicle with secondary minor vascular pedicles
III – Codominant major vascular pedicles
IV – Multiple segmental vascular pedicles
V – Dominant vascular pedicle with segmental secondary pedicles that can supply muscle if dominant is divided
Type II vascular anatomy is seen with the rectus femoris, vastus medialis, and gracilis muscles. The rectus abdominis has a type III vascular anatomy. Type V would be a latissimus dorsi muscle flap.
2017
A 76-year-old woman with a history of left modified radical mastectomy and radiation therapy comes to the office because of a chronic wound of the left axilla associated with limitation of abduction and exposed rib at the wound base. A photograph is shown. Examination of a biopsy specimen excludes malignancy. In addition to appropriate debridement, which of the following is likely to be most effective in achieving wound closure?
A) Adjacent tissue transfer
B) Left latissimus dorsi myocutaneous flap
C) Negative pressure wound therapy
D) Radial forearm fasciocutaneous free flap
E) Split-thickness skin graft
The correct response is Option B.
The best option to achieve wound closure in this patient is an ipsilateral latissimus dorsi myocutaneous flap. For chronic wounds in an irradiated field, the best option is debridement followed by transfer of healthy, nonirradiated tissue. Negative pressure wound therapy is likely to result in a recurrent chronic wound, albeit a clean one. Split-thickness skin graft would be inappropriate in an irradiated wound bed with exposed bone. Autologous fat grafting can help improve the quality of irradiated tissues in the absence of a wound, and some studies have shown promise in the treatment of superficial radiation ulcers; however, this patient has necrotic rib, and following debridement the wound will be deep and large. Although wound management and fat grafting have been shown to promote healing in isolated cases, this approach is not yet an accepted standard of care. Adjacent tissue transfer will employ irradiated tissue, and is thus prone to necrosis, wound breakdown, and recurrent chronic wound formation. A free flap could be an option, but a forearm flap would not have the volume required for the expected defect. In addition, a free flap is more morbid than a local pedicled flap in this elderly patient.
2017
A 55-year-old man who recently underwent a cardiac bypass procedure has a sternal infection that requires debridement. The defect is evaluated, and reconstruction using an omental flap is planned. Which of the following vessels provides the blood supply for this flap?
A) Gastroepiploic
B) Left gastric
C) Right gastric
D) Short gastric
E) Superior mesenteric
The correct response is Option A.
The omental flap is supplied by the gastroepiploic vessels. Common options for sternal wound reconstruction include the pectoralis major, rectus abdominis, latissimus dorsi, and omental flaps. The use of an omental flap for a mediastinal defect was described in the 1970s; however, muscle flaps became a popular choice for reconstruction in the 1980s. Based on the size of the defect, the omental flap can be used with or without a skin graft. The omentum has angiogenic and immunogenic properties that make it ideal for reconstruction of sternal wound infections.
The omentum is based on the left and right gastroepiploic vessels. In order to increase length, the flap can be based on one set of vessels, usually the right gastroepiploic vessels. The left gastroepiploic vessels are a branch of the splenic vessels; the right gastroepiploic vessels are a branch of the gastroduodenal vessels. Harvest can be performed through either an upper abdominal incision, transdiaphragmatic, or laparoscopically. There is a risk of donor site morbidity such as abdominal wound infections or symptomatic hernias.
The superior mesenteric vessels supply the lower part of the duodenum extending to the middle third of the transverse colon, as well as the pancreas. The left and right gastric vessels supply the lesser curvature of the stomach. The short gastric vessels supply a portion of the greater curvature of the stomach and are branches of the splenic vessels. The left and right gastroepiploic vessels supply the greater curvature of the stomach along with the omentum.
2017
A 23-year-old man presents 2 years after sustaining full-thickness burns on the anterior neck. He has undergone tissue expansion and local flap reconstruction of the burn defect. He notes webbing and contracture at the margin of one of the prior flap reconstructions. Three identical 60-degree Z-plasties are planned over a total length of 12 cm. The expected gain in scar length is which of the following?
A) 3 cm
B) 4 cm
C) 6 cm
D) 8 cm
E) 9 cm
The correct response is Option E.
A 60-degree z-plasty lengthens a scar by 75%. If each z-plasty covers 4 cm of scar, each will lengthen the scar by 3 cm, for a total increase of 9 cm. In contrast, a 30-degree z-plasty lengthens an incision by 25%, and a 45-degree z-plasty lengthens an incision by 50%. To prevent undue tension, angles greater than 60 degrees should be avoided.
2017
A 24-year-old man comes to the emergency department because of a dorsal hand injury. Physical examination shows a 6 × 4-cm full-thickness defect with exposed metacarpal bones. A medial sural artery perforator flap for soft-tissue coverage is planned. From which of the following vessels does the vascular pedicle for this flap originate?
A) Anterior tibial
B) Descending genicular
C) Peroneal
D) Popliteal
E) Posterior tibial
The correct response is Option D.
The vascular pedicle for the medial sural artery perforator flap arises from the popliteal vessels.
The medial sural artery flap is a thin, pliable perforator flap that can provide well vascularized soft-tissue coverage, especially for relatively small defects. It is commonly used for head/neck, hand, and lower-extremity defects. The first perforator is frequently found along a line connecting the mid-popliteal area to the medial malleolus at the 8-cm mark from the proximal end. Preoperative planning is facilitated with ultrasound identification of the perforators. Sub-fascial dissection is frequently performed to protect the perforator and blood supply and to allow for a gliding surface for tendon repairs. Donor sites that are narrower than 5 cm can frequently be closed primarily. The main benefit of the medial sural artery perforator flap over an anterolateral thigh flap is the relative thinness of the flap, which can be significant in overweight or obese patients.
2017
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?
A) Medial collateral
B) Posterior radial collateral
C) Posterior ulnar collateral
D) Radial
E) Ulnar
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.
2017
A 73-year-old man comes to the office for evaluation of an 8-cm mandibular defect with commensurate skin loss 6 weeks after sustaining a gunshot wound to the face. Reconstruction with a free fibula composite flap with skin paddle is planned. Which of the following arteries is the most common origin for blood supply to the skin paddle?
A) Anterior tibial
B) Peroneal
C) Popliteal
D) Posterior tibial
E) Sural
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.
2017
A 57-year-old man comes to the office because of a rectourethral fistula that developed after he underwent radiation treatment for prostate cancer. Reconstruction with a pedicled muscle-only gracilis flap is performed. From which of the following directions does the medial femoral circumflex artery pedicle enter the gracilis muscle?
A) Anterior
B) Inferior
C) Lateral
D) Medial
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.
2017
A 45-year-old man is evaluated for unstable plantar scar 3 years after undergoing skin grafting for a traumatic amputation at the tarsometatarsal joints. A photograph is shown. An anterolateral thigh flap is planned for coverage of the resultant plantar defect. Which of the following coaptations is most likely to allow for sensory recovery of the flap?
A) Lateral femoral cutaneous nerve to a deep peroneal nerve branch
B) Lateral femoral cutaneous nerve to a superficial peroneal nerve branch
C) Lateral femoral cutaneous nerve to a tibial nerve branch
D) Medial femoral cutaneous nerve to a deep peroneal nerve branch
E) Medial femoral cutaneous nerve to a tibial nerve branch
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.
2017
A 58-year-old man undergoes a left hemimandibulectomy. Reconstruction with an osteocutaneous free flap harvested from the ipsilateral pelvis is planned. The vascular pedicle supplying this flap is based on which of the following arteries?
A) Ascending branch of the lateral circumflex femoral artery
B) Deep circumflex iliac artery
C) Deep inferior epigastric artery
D) Descending branch of the geniculate artery
E) Peroneal artery
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.
2017
A 50-year-old man is scheduled to undergo mandibulectomy with floor of mouth resection for cancer. An osteocutaneous radial forearm free flap is being considered. Which of the following is the strongest contraindication to performing this flap?
A) Abnormal Allen test
B) Anterior mandibular tumor location
C) Defect length of 8 cm
D) History of prior radiation
E) Lack of availability of ipsilateral neck muscles as recipients
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.
2017
A 35-year-old paraplegic man presents with a 5 × 5-cm pressure ulcer over his left ischium involving the skin, subcutaneous tissue, and bone. After debridement, a gluteal rotation flap is planned for closure. Compared with a transposition flap, which of the following is the most significant benefit of using a rotation flap for coverage of this patient’s wound?
A) Ability to reuse flap for future surgery
B) Decreased recurrence rate
C) Improved pressure relief
D) Improved scar placement
E) Improved vascularity
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.
2016
A 53-year-old woman comes to the office with an exposed vascular graft in the left groin caused by postoperative wound infection. After operative debridement, a proximally based sartorius muscle flap is transferred to cover the graft. Several days after surgery, it is evident that the distal portion of the muscle flap is necrotic. This most likely occurred because the sartorius muscle demonstrates which of the following Mathes-Nahai types of vascular pattern?
A)
B)
C)
D)
E)
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
2016
A 45-year-old man is brought to the emergency department 2 hours after sustaining an avulsion injury to the dorsum of the left hand in a motorcycle accident. Physical examination shows complete loss of the dorsal skin and exposure of the extensor tendons in the dorsal hand with no viable peritenon. Reconstruction of the defect with a lateral arm free flap is planned. Which of the following arterial pedicles will supply this flap?
A) Anterior interosseous
B) Inferior cubital cutaneous
C) Posterior radial collateral
D) Radial recurrent
E) Superior ulnar collateral
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.
2016
A 45-year-old man is evaluated because of a traumatic plantar heel wound following a calcaneal fracture of the left foot. A pedicled fasciocutaneous flap from the plantar instep is designed for reconstruction. Which of the following best describes the anatomic location of the arterial pedicle of this flap?
A) Between the abductor hallucis and flexor digitorum brevis
B) Between the flexor digitorum brevis and abductor digiti minimi
C) Between the flexor hallucis brevis and adductor hallucis
D) Between the flexor hallucis longus and quadratus plantae
E) Between the tendons of the extensor hallucis longus and extensor digitorum longus
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.
2016
Which of the following arteries most likely supplies a vascularized bone free flap from the medial condyle of the femur?
A) Descending genicular
B) Medial femoral circumflex
C) Posterior radial collateral
D) Posterior tibial
E) Sural artery
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.
2016
A 14-year-old girl who has flexion deformities of the right wrist and fingers, numbness of the radial-volar hand, and forearm atrophy 6 months after sustaining an electrical burn to the right upper extremity is brought for evaluation. A functional free gracilis muscle transfer is planned to improve finger flexion. Which of the following nerves innervates this flap?
A) Femoral
B) Genitofemoral
C) Ilioinguinal
D) Obturator
E) Pudendal
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.
2016
A 26-year-old woman is evaluated for burns on the dorsum of the right hand. After serial debridement is performed, the patient has exposed extensor tendons, wrist capsule, and superficial radial nerve. A pedicled groin flap is planned for coverage. Which of the following vessels is most likely to supply arterial blood to the groin flap?
A) Deep circumflex iliac
B) Deep external pudendal
C) Lateral femoral circumflex
D) Superficial circumflex iliac
E) Superficial inferior epigastric
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.
2016
A 50-year-old woman has wound breakdown in the lumbosacral region after spinal instrumentation, as shown in the photograph on the left. The superior aspect is closed with local paraspinal muscle advancement. The lower aspect is closed with a musculocutaneous V-Y advancement flap, as shown in the photograph on the right. Which of the following Mathes/Nahai classifications is most appropriate for this flap?
A) Type I
B) Type II
C) Type III
D) Type IV
E) Type V
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.
2014
A 75-year-old man with a history of renal transplantation presents with a rapidly growing squamous cell carcinoma involving his anterior scalp and forehead. A photograph is shown. Wide excision results in a 20 × 20-cm defect with exposed calvarium. Which of the following flaps is most appropriate for coverage of this wound?
A) Anterolateral thigh free flap
B) Gracilis free flap
C) Lateral arm free flap
D) Radial forearm free flap
E) Rectus abdominis free flap
The correct response is Option A.
The anterolateral thigh (ALT) free flap (shown) is the only option listed with the requisite tissue characteristics, size, and pedicle length necessary to repair a defect of this size and location. The ALT flap has rapidly become a first-line option for covering large or irregular head and neck defects. It is an extremely versatile flap with chimeric options allowing for multiple skin paddles, muscle bulk (vastus lateralis) if needed for dead space obliteration, as well as bone (iliac crest) for midface or small mandibular defects. The tissue thickness is well suited for large scalp defects. Flaps as large as 35 × 25 cm have been described, although defects larger than 10 to 12 cm in width generally require skin grafting the donor site. Pedicle lengths of 12 to 16 cm have been described, which is often long enough to reach the upper neck if necessary.
The radial forearm free flap is an excellent option in many cases, providing a pedicle length up to 18 to 20 cm with maximal dimensions up to 12 × 30 cm. A major criticism of this flap is the poor cosmesis of the donor site and lack of subcutaneous tissue necessary to match the surrounding cutaneous defect. The lateral arm flap based on the radial collateral artery is useful for smaller defects in the head and neck but is limited in this situation by a short pedicle (6 cm) and smaller skin paddle (6 × 12 cm).
Muscle flaps covered with skin grafts have also been described for scalp coverage. When necessary, a latissimus dorsi flap is a great option for near total scalp coverage. With the examples listed here, the gracilis flap is too narrow (5 to 6 cm) with too short a pedicle (medial femoral circumflex, 7 cm). While the pedicle for the rectus free flap (deep inferior epigastric, 8 to 10 cm) might be long enough in this situation, the muscle is not big enough (6 cm wide) to cover the defect.
2019
A 44-year-old man presents with a 20-degree extension deformity of his wrist because of burn scarring. Z-plasty for contracture release is planned. Which of the following (A-D) is the most appropriate placement of the central limb for this procedure in this patient?
A) (see image above)
B) (see image above)
C) (see image above)
D) (see image above)
The correct response is Option A.
Z-plasty is a fundamental and common reconstructive technique used to elongate scars or contractures, narrow scars, rearrange tissues into relaxed skin tension lines, camouflage scars, or releasing tension. This is a form of rotation and advancement whereby a central limb of the Z-plasty is drawn parallel to the line of maximal tension, and subsequent limbs are drawn anywhere from 30 to 90 degrees from this. Wider angles give greater scar elongation at the expense of greater transverse tension.
In this scenario, the line of maximum tension is longitudinal, creating an extension deformity. Maximal contracture release will occur with a central limb of the Z-plasty drawn longitudinally.
2020
A 28-year-old woman presents to the clinic 3 years after she sustained large, full-thickness burns to the anterior neck. She has undergone reconstruction with a fasciocutaneous free flap. She does not like the contracture and webbing along the margin of the reconstruction. Two contiguous 45-degree Z-plasties are planned over a total length of 10 cm. The expected increase in scar length is which of the following?
A) 2.5 cm
B) 5.0 cm
C) 7.5 cm
D) 10.0 cm
E) 12.5 cm
The correct response is Option B.
A 45-degree Z-plasty is expected to lengthen the total scar by 50%. If each Z-plasty covers 5 cm of scar, then each Z-plasty will increase scar length by 2.5 cm, for a total increase of 5 cm. Theoretical gains in length for Z-plasty angles are as follows:
The Z-plasty was the first flap introduced using a mathematical approach to correct a skin defect or scar. A standard Z-plasty design uses three incisions of equal length and two angles of equal degree. The primary principle is to transfer lateral skin excess to lengthen and reorient tight scars or contractures. The central incision is oriented parallel to the long axis of the scar, or the scar may be incorporated as an excision acting as the central incision. The resultant triangular skin flaps are transposed with each other, resulting in a new central incision that is perpendicular to the original orientation.
2021
A 32-year-old man sustains a burn to his hand, resulting in a first web space contracture. A four-flap Z-plasty is planned for release of the contracture. Which of the following best describes the flap reconstruction for this defect?
The correct response is Option F.
Random pattern flaps are generally classified based on the primary motion of the flap. There are three basic types of tissue movement: transposition, advancement, and rotation. Transposition flaps incorporate noncontiguous skin into a defect by lifting the flap over normal skin for inset into a defect. Advancement flaps recruit adjacent tissue to close a defect via soft-tissue movement in a linear direction. Rotation flaps move adjacent tissue around an axis to close a defect, rotating soft tissue into the defect. Advancement and rotation flaps recruit adjacent lax tissue and move in either a linear or arced motion (respectively) to fill the defect. Transposition flaps recruit noncontiguous tissue, which is lifted over intact soft tissue and placed into the defect. Random pattern flaps lack a defined named arterial vascular supply. Because of their lack of an axial vascular supply, they are subject to dimensional restrictions. In general, they are designed to not exceed a length:width ratio of 2:1. An axial pattern flap is a single pedicled flap that has an anatomically named arterial blood supply running along its long axis. Because of the presence of a named arterial blood supply, axial pattern flaps are not subject to the length:width ratio restrictions that apply to random pattern flaps.
2021
A 24-year-old man presents with a burn contracture of the third web space of the hand. A jumping man (five flap) plasty is planned. In this technique, the final position of the central flap is achieved through which of the following techniques?
A) 45-degree transposition
B) 60-degree transposition
C) 75-degree transposition
D) V-Y advancement
E) Y-V advancement
The correct response is Option E.
In the jumping man or five flap plasty, the central flap is advanced through a Y to V method where the tip of the V is advanced into an incision made in the opposing tissue. There are different modifications to this technique for local flap lengthening of flexion contractures. Traditionally, the lateral limbs are designed with 60-degree angles to the central limb and the opposing limbs are designed more obtusely to prevent ischemia at the base. This type of reconstruction requires laxity of the surrounding skin and is therefore most often employed in places like the medial canthus, web spaces of the feet and hands, or the axilla.
A V-Y advancement is commonly used in pressure ulcer repair where the base of the V is advanced into the defect to create a Y. This is the opposite of what one is trying to achieve in a jumping man plasty. Transpositions of 75, 60, and 45 degrees are all different variations of z-plasties and are utilized in this local rearrangement, but the central flap is advanced, not transposed/rotated.
2022
A 36-year-old man undergoes wide local resection of a malignancy on his right lower extremity, resulting in an exposed tendon. Which of the following flaps is most likely to require minimal subcutaneous undermining?
A ) Bilobed
B) Bipedicled
C ) Keystone
D ) Propeller
E) Rhomboid
The correct response is Option C.
A keystone flap does not require significant undermining. Wide undermining would compromise flap perfusion. Various modifications exist, but one standard keystone flap marking includes lines drawn 90 degrees from the superior and inferior edges of a lenticular defect with a width equivalent to that of the defect (X in the photographs). Closure of the donor site is essentially a double V to Y. The other flaps listed require wide undermining to appropriately transpose the flap. A propeller flap is a perforator flap that involves two limbs centered around a perforator. The flap is undermined completely, although the tissue is centered about the perforator. The limb most distal from the defect is rotated 180 degrees to the defect. Rhomboid flaps and bilobed flaps also require undermining and rely on random dermal perfusion. A bipedicled flap is random with a dual dermal blood supply and requires wide undermining
2023
A 45-year-old woman presents with a nasal defect after undergoing Mohs micrographic resection of a recurrent basal cell carcinoma. One year ago, the patient underwent a smaller excision of a basal cell carcinoma in the same area, followed by single-stage reconstruction with a flap from the ipsilateral cheek. Examination shows a transmural defect extending into the nasal cavity. A photograph is shown. Reconstruction of the nasal lining using an interpolated septal flap is planned, along with autologous cartilage grafting to provide structural support. Which of the following is the most appropriate technique for cutaneous reconstruction in this patient?
A) Cervicofacial rotation advancement flap
B) Full-thickness skin graft
C) Ipsilateral interpolated nasolabial flap
D) Paramedian forehead flap
E) “Waltzing” tubed flap
The correct response is Option D.
The patient has a full-thickness nasal defect in which a vascularized flap is used for nasal lining with overlying cartilage grafting. Cutaneous reconstruction will also require a vascularized flap as opposed to a graft due to the cartilage grafting. Given the size and location of the defect, an interpolated option would be best to preserve the alar facial sulcus, which would otherwise be obliterated by a cervicofacial rotation advancement flap or other adjacent tissue transfers. In the setting of a prior reconstruction with an ipsilateral cheek flap, it would be better to avoid an interpolated ipsilateral cheek flap, since the vascularity may be compromised. Although tubed flaps can be “waltzed” from distant sites to the nose, a paramedian forehead flap is the best option since it can be performed in the fewest number of stages.
2023
