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RECONSTRUCTIVE Efficient Design of Split Anterolateral Thigh Flap in Extremity Reconstruction Nai-Jen Chang, Nicholas Waughlock, Dennis Kao, Cheng-Hung Lin, Chih-Hung Lin, Chung-Chen Hsu,

M.D. M.D. M.D. M.D. M.D. M.D.

Taipei, Taiwan

Background: Irregularly shaped and three-dimensional soft-tissue defects in the extremities are difficult to cover precisely and efficiently. One strategy is to use the anterolateral thigh flap with two perforators and split the flap into two subunits based on separate perforators. The subunits can be rearranged into various geometric configurations to cover defects with nonelliptical shapes. Such a strategy emphasizes harvesting an elliptical anterolateral thigh flap with a narrower width to allow for primary closure in most cases. This avoids the need for skin grafting and reduces donor-site morbidity. Methods: From 2002 to 2010, 15 patients with upper and lower limb defects were treated with split anterolateral thigh flaps. There were nine male patients and six female patients. The mean age of the patients was 40.6 years (range, 18 to 64 years). The shape of each defect was classified as arrow-shape, hourglassshape, triangular, or three-dimensional. Results: All split flaps (n ⫽ 31) survived without vascular problems. Two split flaps demonstrated margin necrosis without critical structure exposure. Only one donor site needed skin grafting. All other donor sites were closed primarily. Conclusions: The split anterolateral thigh flap is an effective strategy for covering irregular and three-dimensional defects in the extremities. It allows efficient use of the harvested flap and minimizes trimming and discarding unused flap parts. This decreases the area of skin graft needed for donor-site coverage and may even be able to achieve primary closure. (Plast. Reconstr. Surg. 128: 1242, 2011.) CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

T

he anterolateral thigh flap, based on the lateral circumflex femoral artery, is one of the most reliable and preferred options for covering complicated defects secondary to trauma or tumor ablation. Although a large elliptical flap may be harvested, if one wishes to achieve primary closure of the donor site, the width of the harvested ellipse must be limited to 6 to 9 cm in most cases.1 As a result, when presented with nonelliptical wounds or defects with complex geometric configurations, one may face several dilemmas. For instance, does one make a template of the defect and then design and harvest the anterolateral thigh flap in the dimensions of the template? If so, primary closure of the resulting donor-site defect may not be possible because of the greater From the Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Chang Gung Medical College and Chang Gung University. Received for publication March 6, 2011; accepted March 18, 2011. Copyright ©2011 by the American Society of Plastic Surgeons DOI: 10.1097/PRS.0b013e318230c868

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width of the anterolateral thigh flap design. Even if primary closure is possible, a lot of excess tissue may need to be removed during the process of primary closure to eliminate dog-ears. Such a maneuver wastes a lot of unused tissue at the expense of increased tension of donor-site closure (Fig. 1). Tsai et al.2 used a split cutaneous anterolateral thigh free flap with two skin paddles based on the same pedicle for treatment of postburn contracture, demonstrating reduced donor-site morbidity. Building on the same concept, we present our reconstructive strategy of splitting anterolateral thigh flaps with two perforators to cover extremity defects with nonelliptical or unconventional shapes. Such a strategy increases the efficiency of flap use and minimizes the amount of soft tissue removed from the donor site. Minimizing the amount of soft-tissue removed from the anterolateral thigh donor site can decrease the tension

Disclosure: The authors have no financial interest to declare in relation to the content of this article.

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Volume 128, Number 6 • Split Anterolateral Thigh Flap

Fig. 1. The design of the split flap can decrease the excess tissue removed and decrease the width of the flap during harvest (Y ⬍ X) to achieve donor-site primary closure.

on wound closure, resulting in a more aesthetic scar. It can also minimize the potential need for skin grafting and thereby reduces skin graft–associated anterolateral thigh donor-site morbidities, such as poor appearance, delayed recovery, healing complications, and limited range of motion at the hip and knee.3

PATIENTS AND METHODS From 2002 to 2008, 15 patients with upper and lower limb defects were treated. There were nine male and six female patients. The mean age of the patients was 40.6 years (range, 18 to 64 years). Details regarding patient profile, injury mechanism, location of the defect, design of the reconstruction, flap size, and donor-site management are listed in Table 1. The principle of our flap design strategy was splitting the traditional elliptical flap with two perforators into two separate perforator-based subunits, then rearranging the subunits to mimic the larger, nonelliptical defects with unusual geometric configurations. To minimize donor-site morbidity, the width of the anterolateral thigh flap design was limited to less than or equal to 9 cm to achieve primary closure of the donor site, except in one patient who required a larger flap because of a huge defect. The shape of each defect was classified as an arrow-shape, hourglass-shape, triangular, or three-dimensional. To mimic an arrow-shape defect using the two subunits, one could move the smaller subunit to be one root of

the arrow. For an hourglass-shape defect, the apex of the one subunit could be rotated 180 degrees and placed adjacent to the apex of the other subunit, thereby forming an hourglass configuration. Regarding a triangular defect, two ways of rearrangement were possible. The first way was to create two subunits of unequal size, then move the smaller subunit to be the top of the triangle, forming a new triangle with a slightly wider base but much taller height. The second way was to create two subunits of equal size, then place the subunits side-by-side to form a new triangle with a much wider base but similar height (Fig. 2). For a threedimensional defect, it could be covered by splitting the flap into two subunits to cover the deep portion and the superficial portion of the defect independently. If the deep subunit needed to be buried, the buried portion of the flap could be deepithelialized.

RESULTS

All of the split anterolateral thigh flaps (n ⫽ 31) survived without vascular problems or total flap loss. Two flaps demonstrated marginal necrosis without critical organ exposure and were managed by de´bridement and skin grafting. Most flap donor sites were closed primarily without any complication because the width of the elliptical flap was designed to be within 8 cm. One patient needed shoelace suturing to narrow the defect and split-thickness skin grafting for donor-site coverage because of a larger defect. There was only

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Totally survived — Totally survived One flap shifted Margin necrosis to TFL flap — Totally survived 6⫻6 —



7⫻7 6⫻6 19 ⫻ 8

A 51-year-old man was involved in a traffic accident and presented with an arrow-shape soft-tissue defect over his left lower leg involving both malleoli. A left anterolateral thigh flap with two perforators was split and rearranged into an arrow shape to fit the defect. The donor site was closed primarily. Follow-up at 4 months postoperatively showed a satisfactory outcome (Fig. 3).

Case 4

9⫻7

A 58-year-old woman presented with a large defect involving her dorsal foot and entire heel pad after a traffic accident. The defect resembled the shape of an hourglass. An elliptical anterolateral thigh flap with two perforators was harvested, split, and rearranged to fit the hourglass defect. Because of the size of the flap required, the donor site was partially closed with shoelace sutures and the remaining wound was covered with skin graft. However, the area of skin grafting was much decreased compared with the conventional setting. The patient underwent flap debulking 3 months later. Satisfactory aesthetic and functional results were observed at 6-month follow-up (Fig. 4).

9⫻8 Three-dimensional Crush injury 51 15

F

Left foot

8⫻8 14 ⫻ 7 19 ⫻ 8 Triangle Three-dimensional Three-dimensional F M M 52 45 64 12 13 14

M M M M M 22 18 43 44 48 7 8 9 10 11

M F 23 27 5 6

A 43-year-old man presented with a large triangular defect over his right lower leg, complicated by bone and hardware exposure. A template was used to design the flap. The right anterolateral thigh flap with two perforators was harvested, split, and rearranged into a triangular shape. The donor site was closed primarily and the result was satisfactory (Fig. 5).

Case 14 F, female; M, male; STSG, split-thickness skin graft; TFL, tensor fasciae latae.

20 ⫻ 8 10 ⫻ 8 16 ⫻ 8 13 ⫻ 7 15 ⫻ 7 Hourglass Hourglass Triangle Triangle Triangle

11 ⫻ 5 10 ⫻ 7 Hourglass Hourglass

Arrow Arrow Hourglass 51 20 58 2 3 4

M F F

CASE REPORTS Case 2

Primary

— — — — — 15 ⫻ 8 7⫻4 8⫻7 13 ⫻ 8 15 ⫻ 7

Primary Primary Primary

survived survived survived survived survived Totally Totally Totally Totally Totally — — — —

— — 5⫻4 13 ⫻ 7

Primary Primary Primary Primary Primary

Totally survived Totally survived — —

Margin necrosis Totally survived Totally survived — — — — — — 23 ⫻ 6 19 ⫻ 8 13 ⫻ 13

6⫻4 10 ⫻ 7 9⫻8

Primary Primary Shoelace plus STSG Primary Primary

Totally survived — Primary — 10 ⫻ 8 18 ⫻ 8 Arrow Crush injury F 55 1

Location of Defect Mechanism of Injury Age Patient (yr) Sex

Table 1. Clinical Details

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one anterolateral thigh perforator noted in one patient during the dissection; thus, a skin island supplied by the tensor fasciae latae muscle perforator was included as the other subunit.

Case 9

Left lower leg, ankle and foot Diabetes foot Left ankle Crush injury Right ankle Crush injury Right heel and foot Crush injury Right foot Crush and contact Right hand thermal burn Crush injury Left lower leg Crush injury Left hand Crush injury Left lower leg Electrical burn Right hand Postburn Right hand contracture Crush injury Left foot Crush injury Left foot Crush injury Right foot

Defect Shape

Flap 1 Flap 2 Flap 3 Size (cm2) Size (cm2) Size (cm2)

Donor-Site Closure

Design Modification

Outcome

Plastic and Reconstructive Surgery • December 2011

A 64-year-old man suffered a crush-avulsion injury of the right foot, resulting in a large skin defect on both the plantar and the dorsal sides; exposure of partially amputated second, third, and fourth toes; and a completely amputated fifth toe. A conventional anterolateral thigh flap could not cover the large defect without folding. There was only one anterolateral thigh perforator noted during the dissection; thus, a skin island supplied by the tensor fasciae latae muscle perforator was included. The two flap subunits covered the defect successfully. The donor site was closed primarily. The patient underwent de´bridement and skin grafting 3 weeks later because of the adjacent skin, and partial necrosis occurred in the tip of the tensor fasciae latae subunit (Fig. 6). After skin grafting, the outcome was satisfactory.

DISCUSSION With the development of modern microsurgical reconstruction, difficult defects can be reconstructed with more precision and better functional and aesthetic outcomes.4 However, some challenges remain. One of the challenges is efficient use of flap to cover irregularly shaped defects. In those cases, a wider flap is usually harvested and then trimmed to fit the defect. This often creates more donor-site morbidity than necessary.

Volume 128, Number 6 • Split Anterolateral Thigh Flap

Fig. 2. Split flap design of different irregular defects.

Fig. 3. Case 2. A 51-year-old man presented with an arrow-shape soft-tissue defect over the left lower leg involving bilateral malleolar areas (above, left). A left anterolateral thigh flap was harvested with two different perforators (above, right). The flap was split and reshaped to fit the defect (below).

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Plastic and Reconstructive Surgery • December 2011

Fig. 4. Case 4. A 58-year-old woman presented with a huge hourglass-shape defect over her dorsal foot and heel pad (above). A template was used to design the flap (below, left). The anterolateral thigh flap was split and reshaped to fit the defect (below, right).

Primary closure of the donor site is one of the critical points in achieving satisfactory reconstruction results. Kimata et al. reported that patients who underwent primary wound closure of usually donor sites could perform activities of daily life normally; 87.5 percent of patients were satisfied with their donor-site aesthetic results and only 3.1 percent had limited range of motion at the hip and knee. However, in the split-thickness skin graft group, limited range of motion at the hip and knee was found in 60 percent of patients.3 Furthermore, cold intolerance occurred three times as often after skin grafting than after primary skin closure.5 The anterolateral thigh flap is one of the most versatile tissue donor sites. Many variations and modifications have been described for its use.1,6 Splitting the flap based on different sizable perforators allows for precise tailoring and coverage of irregularly shaped defects wider than 9 cm with only one pedicle while still having a likely chance

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of closing the donor site primarily. Although sporadic cases treated with this technique have been reported previously to cover rectangular, square, or oval defects,2,7 to the best of our knowledge, no defect classification or larger case series has been published. In our series, we classified the defects into four types according to their geometry and present at least three cases for each. We experienced no flap loss and two cases of marginal necrosis. These may have been attributable to perforator pedicle kinking or twisting. Care needs to be taken when insetting the individual split skin paddles to avoid pedicle complications. The split skin paddles are essentially perforator-based flaps and thus susceptible to pedicle kinking, twisting, or compression. The width of the anterolateral thigh flap that can be harvested while still achieving primary closure of the donor site varies from patient to patient. To allow primary closure of the donor site, the width of the anterolateral thigh flap harvested

Volume 128, Number 6 • Split Anterolateral Thigh Flap

Fig. 5. Case 9. A 43-year-old man presented with a triangular defect over his right lower leg, complicated by bone and plate exposure (above, left). A template was used to design the flap (above, right). The anterolateral thigh flap was harvested, split, and reshaped to fit the defect (below).

is usually limited to 6 to 9 cm. Boca et al. suggested that a flap width-to–thigh circumference ratio of 16 percent or lower is a reliable predictor for achieving primary donor-site closure. However, the patient’s body mass index and age are also contributing factors.8 In one of our patients, the defect size was simply too large. A wider anterolateral thigh flap was raised and primary closure of the donor site was not possible. However, the perforator-based flap-splitting strategy still resulted in a much narrower donor defect than would have been achieved otherwise. Perhaps one of the greatest advantages of the strategy described in this article is the ability to cover wider defects with irregular shapes and still be able to achieve primary closure of the donor site. Rearrangement of the subunits after perforator-based flap splitting allows for wider flaps of various configurations to be created. We believe that perforator-based anterolateral thigh flap splitting is particularly help-

ful in extremity reconstruction where irregularly shaped or three-dimensional defects are the norm rather than the exception. As with other types of perforator flaps, applying perforator-based anterolateral thigh flap splitting is not always straightforward, and the technique definitely has an associated learning curve. Several caveats are worth mentioning. The first is that after insetting, care must be taken to observe the lay of the pedicle and the flap circulation to ensure that no pedicle compression, kinking, or twisting occurs.9,10 Second, when raising the anterolateral thigh flap, sometimes only one usable perforator or even none may be found, as anterolateral thigh perforators of the descending branch have been documented to be totally absent in 0.9 to 5.4 percent of cases.1,11,12 In these situations, we recommend modifying the flap design to include a tensor fasciae latae perforator (Fig. 7). The advantage of including a skin paddle based on a

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Plastic and Reconstructive Surgery • December 2011

Fig. 6. Case 14. A 64-year-old man presented with a three-dimensional defect involving the lateral foot and toes (above). There was only one perforator noted in the anterolateral thigh flap; thus, a tensor fasciae latae flap was included (below, left). The two flaps cover the defect efficiently and the donor site can still be closed primarily (below, right).

Fig. 7. Flaps based on the lateral circumflex femoral artery (LCFA) system. AMT, anteromedial thigh flap; TFL, tensor fasciae latae; ALT, anterolateral thigh; PFA, profunda femoris artery.

tensor fasciae latae perforator is that the wound simply needs to be extended more proximally. The flap is still based on the same pedicle and can be closed primarily.13 If a tensor fasciae latae

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perforator is not available, an anteromedial thigh flap can be considered because it shares the same pedicle with the anterolateral thigh flap. However, it requires a longer and more

Volume 128, Number 6 • Split Anterolateral Thigh Flap tortuous intramuscular dissection and almost inevitably needs skin grafting.

CONCLUSIONS The split anterolateral thigh flap based on two perforators offers an efficient means of covering nonelliptical defects while harvesting a conventional elliptical flap. This facilitates primary closure of the donor site and minimizes the need for skin grafting. It also achieves a better aesthetic outcome and decreases donor-site morbidity. Chung-Chen Hsu, M.D. Department of Plastic and Reconstructive Surgery Chang Gung Memorial Hospital 5, Fu-Hsing Street Kuei-Shan, Taoyuan, Taiwan [email protected]

REFERENCES 1. Wei FC, Jain V, Celik N, Chen HC, Chuang DC, Lin CH. Have we found an ideal soft-tissue flap? An experience with 672 anterolateral thigh flaps. Plast Reconstr Surg. 2002;109:2219– 2226; discussion 2227–2230. 2. Tsai FC, Yang JY, Mardini S, Chuang SS, Wei FC. Free splitcutaneous perforator flaps procured using a three-dimensional harvest technique for the reconstruction of postburn contracture defects. Plast Reconstr Surg. 2004;113:185–193; discussion 194–195. 3. Kimata Y, Uchiyama K, Ebihara S, et al. Anterolateral thigh flap donor-site complications and morbidity. Plast Reconstr Surg. 2000;106:584–589.

4. Valdatta L, Tuinder S, Buoro M, Thione A, Faga A, Putz R. Lateral circumflex femoral arterial system and perforators of the anterolateral thigh flap: An anatomic study. Ann Plast Surg. 2002;49:145–150. 5. Mureau MA, Posch NA, Meeuwis CA, Hofer SO. Anterolateral thigh flap reconstruction of large external facial skin defects: A follow-up study on functional and aesthetic recipient- and donor-site outcome. Plast Reconstr Surg. 2005;115: 1077–1086. 6. Ali RS, Bluebond-Langner R, Rodriguez ED, Cheng MH. The versatility of the anterolateral thigh flap. Plast Reconstr Surg. 2009;124:e395–e407. 7. Marsh DJ, Chana JS. Reconstruction of very large defects: A novel application of the double skin paddle anterolateral thigh flap design provides for primary donor-site closure. J Plast Reconstr Aesthet Surg. 2010;63:120–125. 8. Boca R, Kuo YR, Hsieh CH, Huang EY, Jeng SF. A reliable parameter for primary closure of the free anterolateral thigh flap donor site. Plast Reconstr Surg. 2010;126:1558–1562. 9. Masia J, Moscatiello F, Pons G, Fernandez M, Lopez S, Serret P. Our experience in lower limb reconstruction with perforator flaps. Ann Plast Surg. 2007;58:507–512. 10. Wong CH, Cui F, Tan BK, et al. Nonlinear finite element simulations to elucidate the determinants of perforator patency in propeller flaps. Ann Plast Surg. 2007;59:672–678. 11. Choi SW, Park JY, Hur MS, et al. An anatomic assessment on perforators of the lateral circumflex femoral artery for anterolateral thigh flap. J Craniofac Surg. 2007;18:866–871. 12. Kimata Y, Uchiyama K, Ebihara S, Nakatsuka T, Harii K. Anatomic variations and technical problems of the anterolateral thigh flap: A report of 74 cases. Plast Reconstr Surg. 1998;102:1517–1523. 13. Lin YT, Lin CH, Wei FC. More degrees of freedom by using chimeric concept in the applications of anterolateral thigh flap. J Plast Reconstr Aesthet Surg. 2006;59:622–627.

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