SURGICAL TECHNIQUE

Vascularized Heterodigital Island Flap for Fingertip and Dorsal Finger Reconstruction Dang T. Pham, MD,*† David T. Netscher, MD†‡ A heterodigital vascularized island flap can functionally restore large soft tissue defects to the injured fingertip in a single stage. It is optimally used for digits of unequal length so that the donor fingertip is not violated, and the skin island is best taken from the less dominant side of the donor finger. Because it is a transposition flap with a proximal axis of rotation, its transposition arc can also reach the dorsum of an adjacent digit. This article describes how the heterodigital arterialized flap preserves the donor finger digital nerve and distal pulp, thus reducing donor site morbidity. Indications, method of flap elevation, and flap design will be reviewed to optimize case selection, minimize donor site morbidity, and enhance safety of flap elevation and transposition. (J Hand Surg Am. 2015;-(-):-e-. Copyright Ó 2015 by the American Society for Surgery of the Hand. All rights reserved.) Key words Donor site morbidity, fingertip reconstruction, heterodigital island flap, local arterialized flap.

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traditionally used crossfinger flaps and the distal Kutler1 and Atasoy2 pulp flaps, pedicle homodigital and heterodigital island flaps are less constrained by their vascular pedicles and can be completed in a single stage. Although they utilize microvascular dissection principles, they are not as complex as microvascular free flaps. Their versatility enables them to cover a large soft tissue fingertip wound, to transfer over greater distances for both volar and dorsal finger wounds, and have sensory innervation. The goal of fingertip reconstruction is to restore sensate function to the tip with tissue that retains similar OMPARED WITH THE MORE

From the *Department of General Surgery, Houston Methodist Hospital; †Weill Cornell Medical College of Cornell University; and the ‡Division of Plastic Surgery and Department of Orthopedic Surgery, Baylor College of Medicine, Houston, TX. Received for publication April 25, 2015; accepted in revised form June 13, 2015. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: David T. Netscher, MD, Division of Plastic Surgery and Department of Orthopedic Surgery, Baylor College of Medicine, 6624 Fannin St., Suite 2730, Houston, TX 77030; e-mail: [email protected]. 0363-5023/15/---0001$36.00/0 http://dx.doi.org/10.1016/j.jhsa.2015.06.112

volar pulp volume, texture, and contour. Although crossfinger flaps can provide sensate coverage3 as well as a large surface and volume of tissue,4,5 2 separate surgical procedures are required. Cross-finger flaps may also involve immobilizing digits in unnatural positions with resultant possible donor and recipient finger stiffness and contractures, as well as unaesthetic donor finger graft sites.6 The larger vascularized pedicle homodigital island flaps are useful, but may be unsuitable when the pedicle vessels are potentially damaged by crushing injuries and when the geometry of either the soft tissue defect or additional lacerations to the injured finger preclude use of a homodigital vascularized island pedicle flap. Under these circumstances, a heterodigital island flap may be indicated as it offers large surface area soft tissue coverage from a remote location with reliable vasculature and possibly even provide sensation without loss of critical sensation to the donor finger in a single-stage reconstruction. Unlike the originally described neurovascular island flap of Littler,7 the vascularized heterodigital island flap does not include the digital nerve and avoids encroaching on the volar distal digital pulp. Thus, donor morbidity is reduced and one does not have the problem

Ó 2015 ASSH

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Published by Elsevier, Inc. All rights reserved.

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of sensation at the recipient site being referred back to the donor finger. A noninnervated Littler flap has been previously described,8,9 but there was concern regarding venous congestion and the relatively small size of the flap that could be used. We provide the technical details of dissection and transposition of the heterodigital vascularized island flap supplied by the proper digital artery, while leaving the digital nerve and distal volar skin pulp intact in Video 1 (available on the Journal’s Web site at www. jhandsurg.org). Because there are multiple arcs of freedom of transposition of the flap pedicle, the heterodigital island flap can be used for dorsal recipient finger wounds. INDICATIONS 1. Large volar and dorsal finger defects up to 3.5 cm long that may be unsuitable for other flaps such as Kutler and Atasoy flaps. 2. Fingertip wounds that cannot be reached by immediately adjacent tissue transfer and require a flap with a greater arc of rotation. 3. When a single-stage finger soft tissue reconstruction is preferable over a cross-finger flap once it enables total skin closure and minimizes the risk of infection to internal prosthetic devices such as tendon implants or orthopedic hardware. 4. Single-stage reconstruction is desired to allow early digital motion and reduce stiffness. For instance, early postoperative motion may be important after a release of digital flexion contractures. 5. When a digit that may already be compromised by excessive scarring, prior infection, or radiation damage needs additional blood supply to the finger to enhance wound healing.

FIGURE 1: Transverse palmar arches connect ulnar and radial digital arteries. Reprinted with permission from Netscher D, Schneider A. Homodigital and heterodigital island pedicle flaps. In: Rayan GM, Chung KC, eds. Flap Reconstruction of the Upper Extremity: A Master Skills Publication. Rosemont, IL: ASSH; 2009:143e152.10

rise to common digital arteries that travel to the second, third, and fourth web space. At the level of the metacarpophalangeal joints, they divide into proper digital arteries, passing to the adjacent radial and ulnar sides of respective fingers (Fig. 1).10 The paired digital arteries have 3 transverse volar arches that connect ulnar and radial digital arteries at the proximal and middle phalangeal level, and pass distal to the flexor digitorum profundus tendon insertion.11 In addition, the deep palmar arch gives rise to palmar metacarpal arteries, which not only travel dorsally to communicate with the dorsal metacarpal arteries, but also travel distally to join the corresponding common digital arteries.12 Veins follow the deep arterial system as venae comitantes.

CONTRAINDICATIONS 1. Crushing or penetrating injury, especially one that involves multiple digits or the distal palm where pedicle vessels may be injured. 2. Following severe infections in the distal palm where donor vessels may potentially be compromised. 3. These arterialized pedicle flaps may be relatively contraindicated in smokers and those with peripheral vascular disease for fear of vascular compromise to both the transferred flap and the donor finger.

SURGICAL TECHNIQUE Step 1: Preoperative and intraoperative planning Perform a digital Allen test and Doppler examination on the donor finger to ensure that both digital arteries supply the finger adequately. Carry out the procedure under general or regional brachial plexus block with tourniquet

SURGICAL VASCULAR ANATOMY The fingers and hand have a built-in arterial redundancy, which enables design of a variety of arterialized pedicle flaps without compromising circulation to the donor digits. The superficial palmar arterial arch gives J Hand Surg Am.

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FIGURE 2: A Soft tissue defect on little finger. B Template is made of the wound. C Template is drawn on adjacent donor finger. D Preoperative marking for incision.

closure at the proximal edge of the flap at the recipient site will not be excessively tight to compromise the vascular pedicle. Draw out a template on the lateral aspect of the donor finger. The distal extent should not extend beyond the distal interphalangeal joint to avoid encroaching on the digital volar pulp. Ensure, by means of a cutoff piece of vessel loop, that the pedicle length will be long enough to reach the recipient site. Proximal dissection of the vessel into the palm will also free up the soft tissue tethers on the pedicle and allow a modest degree of distal flap advancement into the recipient fingertip. With a large V-Y digital artery homodigital advancement flap, up to 20 mm advancement can be achieved; however, the advancement up an adjacent finger in the heterodigital artery island flap is probably less.13 Next, mark a midlateral incision proximally from the designed flap down the finger with a zigzag across the proximal finger crease into the distal palm. Open the proximal recipient finger to provide a course for the flap pedicle (Fig. 3).

Step 2: Flap dissection Flap incision and elevation start at the volar flap skin outline (Fig. 4A, B).14 Incise directly down to the flexor tendon sheath in this safe dissection plane. Elevate the digital neurovascular structures in the flap as one proceeds laterally and dorsally in this plane. Precisely dissect and cauterize the transverse communicating branches, as they are tethers to subsequent flap elevation. The key to the flap elevation and dissection is release of Cleland ligaments, which are on the dorsal (deep) aspect of the flap as it is elevated from the flexor tendon sheath. Release these fibrous tethers and then

FIGURE 3: Proximal portions of the donor, and the recipient finger is opened to allow the flap to be transposed to the adjacent finger.

control and loupe magnification. Exsanguination with an elasticized bandage is preferred over a rubberized Esmarch bandage, as this will retain some blood in the vessels for ease of dissection and identification. Make a template of the wound using a cutoff Esmarch bandage (Fig. 2). Design the template with an additional proximal edge dart so that at the time of insetting, wound J Hand Surg Am.

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FIGURE 4: A Preoperative marking for volar flap incision. B Cross-section of digit demonstrating Cleland ligament dorsal to neurovascular bundle and Grayson ligament. C Volar flap is dissected proximally to the branch point of the common digital artery. D Flap containing the neurovascular bundle is elevated off the flexor tendon sheath with the release of Cleland ligaments.

FIGURE 5: Dorsal incision can be safely completed once the neurovascular pedicle has been captured within the flap. The digital nerve is dissected from the flap, retaining donor fingertip sensation.

divide the transverse digital branch. Microvascular dissection instruments are required. The dorsal flap incision is now complete, once one is certain that the digital neurovascular structures are included in the flap (Fig. 4C, D). Dissect the digital nerve out from the flap and leave in situ as demonstrated in Figure 5. Divide the digital artery distally, and dissect the vascular pedicle back to the bifurcation of the common digital artery in the palm and transpose to the adjacent finger. Dissect the pedicle with a generous fibro fatty cuff of tissue to preserve venae comitantes and venous outflow from the flap. During this dissection, the dorsal digital nerve can be located and cut proximally from its take-off from the J Hand Surg Am.

proper digital nerve. This can be used for subsequent microneural sensory reinnervation of the flap. Step 3: Flap insetting One may choose to pass the flap deep to the bifurcation of the common digital nerve or volar, depending on the most direct path to avoid pedicle kinking. Full-thickness skin grafting is required for the donor site, and the groin is often our preferred site as it has the advantage of less visible scar. Interrupted sutures repair the recipient defect and inset the flap (Fig. 6). Release the tourniquet to assess vascularity of the skin island. Occasionally, corrective action is required, such as release of a few sutures or unkinking of the vascular pedicle if the flap appears r

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3. All flaps, whether innervated or noninnervated, are able to detect light touch, temperature, and sharp stimuli,17 but innervated flaps have better 2-point discrimination (mean 6.2 mm) than noninnervated flaps (mean 10.2 mm). In another study, these were respectively noted to be 3.9 mm and 6.8 mm.15 4. Cold intolerance is reported; however, the incidence is reported as being independent of whether healing is by secondary intention, bone shortening, or reconstruction.18 It seems that cold intolerance is more a result of the injury and not the reconstruction. 5. Flexion contractures may occur as a result of the initial injury as well as secondary to scar contracture. They may also result from stretching the flap pedicle too tightly. It is important to mobilize the pedicle sufficiently so that the flap is brought tension-free to the defect rather than the finger defect brought down to the flap. 6. Donor site and flap recipient site may show hyperesthesia, hyperpigmentation, and contour deformity. None of our patients with heterodigital vascularized island flaps had flap necrosis, and all patients had at least protective sensation, whether innervated or noninnervated. The 2 cases presented both had normal sensation (5 mm, 2-point discrimination), regardless of innervation. The reconstructed digit was used in activities of daily living and not excluded. There were no flexion contractures.

FIGURE 6: Final flap inset and closure. Full thickness skin graft is required for closure of donor defect.

inadequately perfused. This can be overlooked if the dressings were applied before tourniquet pressure release. Step 4: Dressings and postoperative care Nonadherent dressing such as Adaptic (Systagenix Wound Management, North Yorkshire, UK) and conforming but nonconstricting dressings are applied. Splint the hand and fingers in a safe position. Initial healing takes approximately 7e10 days, and range of motion exercises is then begun. Hand therapy and night extension splinting is only necessary to prevent and treat potential proximal interphalangeal flexion contractures.

PEARLS AND PITFALLS 1. The recipient wound should generally be on a shorter finger than the donor finger to avoid violating the distal volar pulp pad; however, this is not essential. As discussed in the technique section and demonstrated in Case 2, releasing the proximal fascial attachments on the pedicle enabled the flap to be advanced further along the longer recipient finger while preserving the donor finger distal pulp. 2. Include a generous cuff of fatty tissue on the pedicle as this contains venae comitantes for adequate venous drainage, thus avoiding venous congestion in the flap. 3. The flap should be transposed to the recipient digit with that finger in full extension to reduce the risk of flexion contracture. 4. The donor site should be located more on the lateral side of the digit. This has 3 potential advantages: (a) Skin graft of the donor area is relatively hidden; (b) risk of linear scar contracture is reduced because there is less of the donor defect on the volar aspect of the digit; and (c) an innervated flap island can be raised using the dorsal digital nerve branch.

COMPLICATIONS Specific incidence and complications for the heterodigital arterialized island flap are not well described, but generalizations can be drawn from publications on homodigital and heterodigital flaps as a whole: 1. In 52 reconstructed fingers, flap necrosis occurred in only 2.15 2. Two-point sensory discrimination for neurovascular island advancement flaps ranged from 3 to 7 mm in 84% of cases in 1 series,16 but 12.5% of those with index tip reconstructions excluded the index finger in fine pinch activities. J Hand Surg Am.

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FIGURE 7: A Loss of distal pulp after an avulsion injury of the little finger. B Digital artery is dissected proximally to the common digital artery bifurcation, and the digital nerve is dissected away from the flap. C Final flap inset and skin graft after transposition. D Long-term outcome with fully sensate volar fingertip. Reprinted with permission from Netscher D, Schneider A. Homodigital and heterodigital island pedicle flaps. In: Rayan GM, Chung KC, eds. Flap Reconstruction of the Upper Extremity: A Master Skills Publication. Rosemont, IL: ASSH; 2009:143e152.10

FIGURE 8: A Vascular malformation on the middle fingertip is outlined for excision, and a template is drawn on the adjacent donor finger. B Dorsal digital nerve is coapted to the digital nerve in the recipient finger after heterodigital flap transposition from the index finger (white arrow). C, D Finger flexion and sensation is preserved at long-term follow-up.

5. Exsanguination of the extremity with an elastic bandage instead of a rubber Esmarch bandage allows more retention of blood in the vessels, rendering their dissection and identification easier. 6. Release the tourniquet before dressing application to assess vascularity of the flap and allow correction if needed. 7. Dissect the flap off the volar aspect of the flexor tendon sheath and take down Cleland ligaments as one dissects laterally. Make the dorsal flap incision only when one is sure that the digital artery is included in the flap.

Case 2 A 10-year-old girl had a vascular malformation of the middle finger that recurred after 2 prior attempts at excision (Fig. 8). The lesion involved the deep dermis; thus, the next excision included the overlying skin. Transposition heterodigital flap came from the ulnar side of the index finger. This was an innervated flap with microneural repair done between the dorsal digital nerve of the flap and the finger proper digital nerve. Normal sensation returned to the reconstructed fingertip.

CASE ILLUSTRATIONS Case 1 An 11-year-old boy had an avulsed volar little finger injury from his hand being dragged on the ground in a go-kart accident (Fig. 7). The little finger is frequently involved with large volar avulsion injuries because it is the most lateral digit and thus most often harmed. In this case, the longer ring finger was ideally suited for heterodigital flap reconstruction to the little finger. In the long term, this patient gained contour reconstruction and excellent finger function. The donor site was relatively unobtrusive.

REFERENCES

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1. Kutler W. A new method of fingertip amputation. JAMA. 1947;133(1):29e30. 2. Atasoy E, Iokinides E, Kasden ML, Kutz JE, Kleinert HE. Reconstruction of the amputated finger with a triangular volar flap. J Bone Joint Surg Am. 1970;52(5):921e926. 3. Cohen BE, Cronin ED. An innervated cross-finger flap for fingertip reconstruction. Plast Reconstr Surg. 1983;72(5):688e697. 4. Cronin TD. The cross-finger flap: a new method of repair. Am Surg. 1951;17(5):419e425. 5. Wolf JM. Cross-finger flap. In: Rayan GM, Chung KC, eds. Flap Reconstruction of the Upper extremity: A Master Skills Publication. Rosemont, IL: ASSH; 2009:57e65. 6. Koch H, Kielnhofer A, Hubmer M, Charnagl E. Donor site morbidity in cross-finger flaps. Br J Plast Surg. 2005;58(8):1131e1135.

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13. Lanzetta M, Mastropasqua B, Sholer A, Brisobois N. Versatility of the homodigital triangular neurovascular island flap and fingertip reconstruction. J Hand Surg Br. 1995;20(6):824e829. 14. Zancolli E. Structural and Dynamic Bases of Hand Surgery. 2nd ed. Philadelphia, PA: Lippincott; 1979. 15. Lai CS, Lin SD, Chou CK, Tsai CW. A versatile method for reconstruction of finger defects: reverse digital artery flap. Br J Plast Surg. 1992;45(6):443e453. 16. Foucher G, Smith D, Penpinello C, Braun FM, Citron N. Homodigital neurovascular island flap for digital pulp loss. J Hand Surg Br. 1989;14(2):204e208. 17. Han SK, Lee DI, Kim WK. The reverse digital artery island flap: clinical experience in 120 fingers. Plast Reconstr Surg. 1998;101(4):1006e1011. 18. Van de Berg WB, Vergeer RA, van der Sluis CK, ten Duis HJ, Werker PMN. Comparison of three types of treatment modalities on the outcome of fingertip injuries. J Trauma Acute Care Surg. 2012;72(6):1681e1687.

7. Littler JW. The neurovascular pedicle method of digital transposition for reconstruction of the thumb. Plast Reconstr Surg. 1953;12(5): 303e319. 8. Rose EH. Local arterialized island flap coverage of difficult hand defects preserving donor digital sensibility. Plast Reconstr Surg. 1983;72(6):848e857. 9. Weeks PM. Discussion of Rose EH: local arterialized island flap coverage of difficult hand defects preserving donor digit sensibility. Plast Reconstr Surg. 1983;72(6):858. 10. Netscher D, Schneider A. Homodigital and heterodigital island pedicle flaps. In: Rayan GM, Chung KC, eds. Flap Reconstruction of the Upper Extremity: A Master Skills Publication. Rosemont, IL: ASSH; 2009:143e152. 11. Nystrom NA, Sedele G, Zoldos J. Intrinsic vascular anatomy of the hand. Atlas Hand Clinics. 1998;3:1e32. 12. Strauch B, de Maura W. Arterial systems of the fingers. J Hand Surg Am. 1990;15(1):148e154.

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Vascularized Heterodigital Island Flap for Fingertip and Dorsal Finger Reconstruction.

A heterodigital vascularized island flap can functionally restore large soft tissue defects to the injured fingertip in a single stage. It is optimall...
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