Original Article 551

Distally Based Iliotibial Band Flap: Anatomic Study with Surgical Considerations

Victor W. Wong, MD1 JamesP.Higgins,MD1

1 The Curtis National Hand Center, MedStar Union Memorial Hospital, Address for correspondence James P. Higgins, MD, Care of Anne Baltimore, Maryland Mattson, The Curtis National Hand Center, MedStar Union Memorial Hospital, 3333 North Calvert Street, #200 JPB, Baltimore, MD 21218 J Reconstr Microsurg 2016;32:551–555. (e-mail: [email protected]).

Abstract Background Reconstruction of high-risk , tendon, or ligament defects may benefit from vascularized tissue. The iliotibial band (ITB), a thick fibrous tract of connective tissue, serves as a potential donor site for free tissue transfer but its blood supply has not been thoroughly investigated. The aim of this anatomical study was to investigate the vascular supply to the distal ITB and its role as a free fascial flap. Methods We dissected 16 fresh-frozen cadaveric legs and injected latex into the superolateral geniculate artery (SLGA). A distal ITB fascial flap was designed and measurements were taken for flap dimensions, pedicle length and size, and SLGA perfusion territory. Results The SLGA perfused 11.5 2.3 cm of distal ITB (proximal to the lateral femoral epicondyle) and provided 6.4 0.7cm of pedicle length to the ITB flap. Conclusions Chimeric options to include bone (from the lateral femoral condyle), Keywords cartilage (from the lateral femoral trochlea), muscle (from vastus lateralis or biceps ► iliotibial band femoris), and skin are possible. Surgical harvest techniques are proposed, including ► cadaver study preservation of ITB insertions to minimize lateral instability. Clinical validation is ► free flap needed to determine the role of the distal ITB free fascial flap in reconstructive ► reconstruction microsurgery.

The human body is held together by fibrous sheets of fascia donor site that combines mechanical strength, versatility, that envelop muscles and organs. Intrinsic, posttraumatic, or ease-of-harvest, minimal morbidity, and the potential for surgical defects in these connective tissue layers can result in composite tissue reconstruction. considerable morbidity. Reconstructive strategies such as The distal lateral soft tissues and the lateral local tissue flaps, nonvascularized autografts, and allograft femoral condyle (LFC) are both supplied by the supero- materials yield acceptable outcomes under most circumstan- lateral geniculate artery (SLGA).4,5 The interposed iliotibial ces. However, in the setting of infection, ischemia, fibrosis, or band (ITB) has been used both as a nonvascularized graft This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. radiation, vascularized tissue-based reconstruction may have (for shoulder and heel reconstruction) and as a pedicled – – benefits over nonvascularized options.1 3 flap (for lateral knee reconstruction) (►Fig. 1A).6 8 How- Some drawbacks of vascularized fascial flaps for recon- ever to our knowledge, the vascular anatomy of the distal struction include limited donor sites, potential harvest mor- ITB and its potential use as a microvascular free flap has not bidity, and lack of mechanical strength. Although flaps from been described in the English literature. The purpose of this the temporoparietal and anterolateral thigh regions have study is to define the distal ITB fascial flap as supplied by been well-described, we sought to investigate an alternate the SLGA.

received Copyright © 2016 by Thieme Medical DOI http://dx.doi.org/ January 18, 2016 Publishers, Inc., 333 Seventh Avenue, 10.1055/s-0036-1583278. accepted after revision New York, NY 10001, USA. ISSN 0743-684X. March 7, 2016 Tel: +1(212) 584-4662. published online May 2, 2016 552 Iliotibial Band Flap Wong, Higgins

Fig. 1 (A) Lateral view schematic of the right ITB. Note ITB insertions onto P, LFC, , and fibular head. (B) Photograph of lateral right thigh showing curvilinear incision to expose posterior aspect of ITB (yellow arrow). (C) Cadaver dissection with skin flap reflected showing ITB inserting onto P and LFC. Angiocatheter with blue latex has cannulated the SLGA. (D) ITB fascial flap has been raised demonstrating the main SLGA trunk beneath (red arrows). Deep transverse branches of the SLGA supplying the LFC have not been exposed from beneath the adipose/areolar tissues in this preparation. Lateral knee joint has been opened to show articular surface of LFC. The clamp is exposing the popliteal artery. BF, biceps femoris; ITB, iliotibial band; LFC, lateral femoral condyle; P, patella; SLGA, superolateral geniculate artery; VL, vastus lateralis.

Materials and Methods Measurements were taken of ITB perfusion length (proximal to the LFC), femur length (from the joint line at LFC to the A total of 16 fresh-frozen cadaveric limbs were dissected superior aspect of the greater trochanter), SLGA origin diameter, using a standard surgical approach under 3.5 loupe magni- SLGA origin distance proximal to knee joint line, and ITB flap fication. A curvilinear incision was designed along an axis pedicle length. Photographs were taken using a digital camera between vastus lateralis and the biceps femoris extending to (SonyCybershotDSCRX-100,SonyElectronicsInc.,NewYork, the LFC (►Fig. 1B). The dissection proceeded along the NY). Data were analyzed using Microsoft Excel 2007 (Microsoft posterior border of the thickened fibers of the ITB and Corporation, Redding, WA). Values are represented as mean through the lateral intermuscular septum to enter the popli- standard deviation.

teal space. The popliteal vessels were identified within the This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. fi fi broadipose tissue, and the SLGA origin was identi ed at the Results popliteal artery. The SLGA was cannulated and flushed with normal saline The average cadaver age was 69 14 years (range: 42–89 using an angiocatheter (range 18–24 gauge) until clear efflu- years). The SLGA was identified in all 16 specimens and ent was noted. Intra-arterial injections of blue latex rubber originated from the popliteal artery 4.4 1.0 cm (range: (Carolina Biological Supply Company, Burlington, NC) were 3.0–6.5 cm) proximal to the knee joint. Average SLGA performed and allowed to cure for 24 hours at 4°C (►Fig. 1C). diameter at its origin was 1.6 0.3 mm (range: 1.0–2.0 In six legs, pink latex injection of the descending branch of the mm). At least one branching geniculate vein of similar size lateral femoral circumflex artery (DLFCxA) was performed was found traveling with the SLGA in the popliteal fossa. concomitantly. Next, the SLGA was dissected to its distal The SLGA consistently coursed transversely along the distal branches, and surrounding soft tissues were dissected in femur just proximal to the lateral femoral epicondyle and the context of harvesting a vascularized ITB free flap obliquely toward the superior aspect of the patella. Deep (►Fig. 1D). Chimeric designs incorporating vascularized transverse and longitudinal branches were directed toward bone, muscle, and skin were also evaluated in four specimens. the proximal and distal LFC, respectively, and a main

Journal of Reconstructive Microsurgery Vol. 32 No. 7/2016 Iliotibial Band Flap Wong, Higgins 553 superficial transverse branch consistently provided perfo- knee.11 The vascular supply of the ITB has been less well- rators to the ITB, , and overlying skin. studied. Because of its close association with vastus lateralis, Perfusion of the ITB extended 11.5 2.3 cm (range: 7– its perfusion has been largely attributed femoral profunda 15cm) proximal to the lateral femoral epicondyle, accounting artery perforators via the lateral intermuscular septum and/ for approximately 28 5% (range: 17–34%) of the LFC-greater or branches of the lateral femoral circumflex system.12,13 trochanter distance. The perfusion territory was most dense Perfusion of the distal ITB was initially noted during at the distal IT band, and perforating branches of the SLGA perfusion studies of the SLGA in the context of osseous flaps coursed through the fascia between the adipose tissue planes from the LFC.4 Interestingly, there was no overlap of ITB surrounding the ITB. The main SLGA trunk was always found perfusion when both the SLGA and DLFCxA artery were immediately deep to the ITB within a 2 cm2 region proximal to injected with latex. The proximal- to mid-thigh level ITB a line drawn between the lateral femoral epicondyle and was supplied by the DLFCxA, whereas up to 12 cm of the midpatella. The distally based ITB flap had a pedicle length of distal ITB were solely supplied by the SLGA. These findings are 6.4 0.7 cm (range: 5.5–8 cm) from the SLGA origin. consistent with a recent study demonstrating that the LFCxA Small intramuscular perforators within vastus lateralis exclusively supplied the proximal two-thirds of the ITB via a directly supplied the ITB proximally but this appeared to be thin layer of areolar tissue.14 Although vascular connections a secondary source. In a subset of six legs with pink latex exist between the DLFCxA and SLGA, perfusion of the distal perfusion of the DLFCxA, there was no overlap with SLGA ITB appears exclusively dependent upon the SLGA. perfusion (blue latex) (►Fig. 2). The pink latex perfusion The ITB is a broad, thick sheet of fascia that has been supplied the mid- to proximal IT band via vastus lateralis harvested as a free, non-vascularized graft for shoulder and intramuscular perforators. The average size of skin paddle Achilles ligament reconstruction.15,16 As a proximally based perfusion was 11.9 2.4 cm length (range: 8–15 cm) and pedicled flap, the ITB has been employed in conjunction with 8.8 1.3 cm wide (range: 6–10 cm). tensor for trochanteric ulcer coverage or with the anterolateral thigh flap for abdominal wall reconstruc- 17,18 fl Discussion tion. As a distally based pedicled ap, it has been used for knee ligament reconstruction (without specific attention The ITB is a thick condensation of connective tissue along the to its vascular supply) and as a fasciocutaneous flap for lateral thigh that originates at the and proximally encases popliteal fossa resurfacing (published in Chinese).6,7,19 Its tensor fascia lata and receives most of the use as a free flap has also been described in the Chinese tendon.9 Distally, the ITB continues as the lateral thickening of literature.20 The authors reported positive results in 11 the fascia lata (which surrounds the entire thigh) before patients with combined Achilles and skin defects who were inserting onto the LFC, patella, lateral condyle of the tibia treated with proximally based anterolateral thigh/ITB flaps. (Gerdy tubercle), and fibular head.10 It functions to resist hip However, based on our cadaveric findings, the vascularity of adduction and internal rotation as well as stabilize the lateral the ITB based on non-SLGA sources may not be reliable. This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.

Fig. 2 Lateral view of cadaveric left leg showing SLGA perforators traveling through the loose areolar/adipose tissue and supplying the distal ITB (blue latex). Perforators from the descending branch of the lateral femoral circumflex artery (pink latex) pierce the mid- to proximal ITB/fascia lata of thigh (red arrows) and supply the overlying skin. Skin perfusion of the distal lateral thigh is shown (blue arrow). Blue dashed line represents proximal extent of SLGA perfusion. ITB, iliotibial band; LFC, lateral femoral condyle; P, patella; SLGA, superolateral geniculate artery.

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Because it is positioned between thin layers of adipose chimeric fascia flap with an average pedicle length of tissue, the ITB can potentially be used as a vascularized fascial 6.4 cm and arterial diameter of 1.6 to 1.8 mm and a skin flap for contour resurfacing or as a gliding layer for tendon paddle along the distal lateral thigh measuring up to 15 cm reconstruction. Thin fascial flaps such as the temporoparietal by 10 cm.4 flap are well-established for craniofacial and hand cover- Technical points for surgical harvest include preserving age.21,22 Additionally, thin fascia-only flaps from the antero- the ITB insertions onto the patella and LFC and designing lateral thigh, serratus anterior, radial forearm, and upper back the fascial flap distally (along the thigh axis) at a line have been successfully used for extremity reconstruc- connecting the lateral femoral epicondyle to midpatella. – tion.23 26 Another described donor site is the rectus abdom- TheSLGAcoursestowardthepatellawithina2cm2 area inis sheath which may provide thick fascia but is associated proximal to this imaginary line, immediately under the ITB. with greater morbidity.27 Compared with the radial forearm If a skin paddle is needed, it should be centered over the or temporoparietal fascial flaps, the ITB fascia is thicker, may planned ITB harvest to maximize the inclusion of cutaneous have larger dimensions, and the donor-site scar may be less perforators coursing through the fascia. By dividing the conspicuous. In contrast to the anterolateral thigh fascia flap, SLGA pedicle distal to the planned ITB flap (after identify- the shorter pedicle and smaller diameter of the distal ITB ing branches to the LFC and vastus lateralis), one can then fascia flap may provide better vessel size match and dimen- incise the ITB flap borders, preserve the areolar/adipose sions for less extensive anatomical defects. layers “sandwiching” the fascia, and raise the fascial flap We propose that the distal ITB flap may provide a thick toward the SLGA origin (from distal to proximal along the sheet of fascia (up to 11.5 cm in length) that can be readily pedicleaxis).BecausetheperforatorsfromtheSLGAtothe harvested with minimal morbidity. It may have a clinical role ITBaresmall,oneshouldneitherattempttodissectthem not only in resurfacing or providing a vascular bed but also in out, nor separate the ITB from the underlying SLGA. Addi- structural reconstruction of fascia, ligaments, and tendons tional SLGA branches are directed to vastus lateralis and the that would benefit from mechanical strength. The width of LFC periosteum (via deep transverse branches). The SLGA ITB that can be safely harvested without compromising lateral courses toward its origin from the popliteal artery in a knee stability remains unknown, although up to 5 cm of plane approximately 5 cm proximal to the LFC–tibia width has been clinically reported and was used in our joint line. study.20 By preserving its distal attachments to the patella, Future studies are needed to assess the effect of distal ITB LFC, tibia, and fibula (as we have designed in our harvest), the harvest on lateral knee and hip instability. More importantly, impact on hip and knee kinematics can potentially be mini- clinical validation is required to determine its potential role in mized. We have also explored the possibility of chimeric reconstructive microsurgery. Given its ease of harvest, options (►Fig. 3) because the SLGA supplies bone (LFC), consistent anatomy, chimeric possibilities, and mechanical cartilage (lateral femoral trochlea), muscle (vastus lateralis, strength, we believe the distally based ITB vascularized flap short head biceps femoris), and skin in addition to fascia may have an indication for high-risk extremity or craniofacial (ITB).4,5,13 The distal ITB flap could serve as a versatile, defects with composite tissue loss. This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.

Fig. 3 (A) Lateral in situ view of distal left thigh after harvest of a chimeric flap based on the SLGA (red arrows). (B) Note blue latex perfusion of the LFC corticoperiosteal flap, VL muscle, ITB fascia, and skin paddle. In this preparation, the deep transverse SLGA branch supplying the LFC appears truncated because the posterior LFC was designed in close proximity to the main pedicle. Scale bar ¼ 2 cm. BF, biceps femoris; ITB, iliotibial band; LFC, lateral femoral condyle; P, patella; SLGA, superolateral geniculate artery; VL, vastus lateralis.

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Conclusions 10 Birnbaum K, Siebert CH, Pandorf T, Schopphoff E, Prescher A, Niethard FU. Anatomical and biomechanical investigations of the – The SLGA reliably perfuses 11.5 cm length of the distal ITB. A iliotibial tract. Surg Radiol Anat 2004;26(6):433 446 11 Louw M, Deary C. The biomechanical variables involved in the free fascial flap can be readily harvested with a pedicle length aetiology of in distance runners - A system- of 6.4 cm and adjacent bone, cartilage, muscle, and skin can be atic review of the literature. Phys Ther Sport 2014;15(1):64–75 incorporated as a chimeric construct. Preservation of the ITB 12 Wong CH, Lin CH, Fu B, Fang JF. Reconstruction of complex insertions onto the patella, LFC, and fibula may minimize abdominal wall defects with free flaps: indications and clinical knee instability. Clinical studies are needed to determine the outcome. Plast Reconstr Surg 2009;124(2):500–509 role of the distally based ITB fascial flap in reconstructive 13 Hayashi A, Maruyama Y. Lateral intermuscular septum of the thigh and short head of the : an anatomic investi- microsurgery. gation with new clinical applications. Plast Reconstr Surg 2001; 108(6):1646–1654 14 Tokumoto H, Akita S, Mitsukawa N, et al. An anatomical and Funding histological study of the vascularized iliotibial tract graft. Micro- Funding provided by the Raymond M. Curtis Research surgery 2015 (e-pub ahead of print). doi: 10.1002/micr.30006 15 Hu R, Ren YJ, Yan L, et al. A free anterolateral thigh flap and Foundation, The Curtis National Hand Center. iliotibial band for reconstruction of soft tissue defects at children’s feet and ankles. Injury 2015;46(10):2019–2023 fl Con ict of Interest 16 Iorio ML, Han KD, Evans KK, Attinger CE. Combined Achilles No conflict of interest to disclose. tendon and soft tissue defects: functional outcomes of free tissue transfers and tendon vascularization. Ann Plast Surg 2015;74(1):121–125 17 Sacks JM, Broyles JM, Baumann DP. Flap coverage of anterior References abdominal wall defects. Semin Plast Surg 2012;26(1):36–39 fl 1 Hamada Y, Hibino N, Kobayashi A. Expanding the utility of modi- 18 Burm JS, Yang WY. Distally extended tensor fascia lata ap fied vascularized femoral periosteal bone-flaps: An analysis of its including the wide iliotibial tract for reconstruction of trochan- form and a comparison with a conventional-bone-graft. J Clin teric pressure sores. J Plast Reconstr Aesthet Surg 2011;64(9): Orthop Trauma 2014;5(1):6–17 1197–1201 2 Terzis JK, Kostopoulos VK. Vascularized nerve grafts and vascu- 19 Zheng X, An HB, Chen T, Wang HB. [The lateral superior genicular larized fascia for upper extremity nerve reconstruction. Hand (NY) artery perforator iliotibial band flap for the treatment of scar 2010;5(1):19–30 contraction of popliteal fossa]. Zhongguo Gu Shang 2013;26(2): – 3 Singer DI, Morrison WA, Gumley GJ, et al. Comparative study of 128 130 vascularized and nonvascularized tendon grafts for reconstruction 20 Wang C, Yu D, Cong H. [Primary repair of tissue defects of achilles of flexor tendons in zone 2: an experimental study in primates. tendon and skin by free grafting of anterolateral femoral skin flap J Hand Surg Am 1989;14(1):55–63 and iliotibial tract]. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi – 4 Wong VW, Bürger HK, Iorio ML, Higgins JP. Lateral femoral condyle 2006;20(10):1037 1039 flap: an alternative source of vascularized bone from the distal 21 Jaquet Y, Higgins KM, Enepekides DJ. The temporoparietal fascia femur. J Hand Surg Am 2015;40(10):1972–1980 flap: a versatile tool in head and neck reconstruction. Curr Opin – 5 Hayashi A, Maruyama Y. The lateral genicular artery flap. Ann Plast Otolaryngol Head Neck Surg 2011;19(4):235 241 Surg 1990;24(4):310–317 22 Taghinia AH, Carty M, Upton J. Fascial flaps for hand reconstruc- – 6 Mascarenhas R, McConkey MO, Forsythe B, Harner CD. Revision tion. J Hand Surg Am 2010;35(8):1351 1355 anterior cruciate ligament reconstruction with bone-patellar ten- 23 Fassio E, Laulan J, Aboumoussa J, Senyuva C, Goga D, Ballon G. don-bone allograft and extra-articular iliotibial band tenodesis. Serratus anterior free fascial flap for dorsal hand coverage. Ann Am J Orthop 2015;44(4):E89–E93 Plast Surg 1999;43(1):77–82 7 Stensbirk F, Thorborg K, Konradsen L, Jørgensen U, Hölmich P. 24 Colen LB, Pessa JE, Potparic Z, Reus WF. Reconstruction of the Iliotibial band autograft versus bone-patella-tendon-bone auto- extremity with the dorsal thoracic fascia free flap. Plast Reconstr graft, a possible alternative for ACL reconstruction: a 15-year Surg 1998;101(3):738–744 prospective randomized controlled trial. Knee Surg Sports Trau- 25 Medina MA III, Salinas HM, Eberlin KR, et al. Modified free radial matol Arthrosc 2014;22(9):2094–2101 forearm fascia flap reconstruction of lower extremity and

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Journal of Reconstructive Microsurgery Vol. 32 No. 7/2016