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 fascia, 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 Æ 2.3 cm of distal ITB (proximal to the lateral femoral epicondyle) and provided 6.4 Æ 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 knee 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 thigh 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, tibia, 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 running 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 Â3.5 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 Æ 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 Æ 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 Æ 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 Æ 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, vastus lateralis muscle, and overlying skin. studied. Because of its close association with vastus lateralis, Perfusion of the ITB extended 11.5 Æ 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 Æ 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 Æ 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 Æ 2.4 cm length (range: 8–15 cm) and pedicled flap, the ITB has been employed in conjunction with 8.8 Æ 1.3 cm wide (range: 6–10 cm). tensor fascia lata for trochanteric ulcer coverage or with the anterolateral thigh flap for abdominal wall reconstruc- 17,18 fl Discussion tion.