Flaps in the Hand

Aims The treatment objectives in hand reconstruction are to: close the wound maximize sensory return preserve length maintain joint function obtain a satisfactory cosmetic appearance

 The volar pulp is also stabilized by the Grayson and Cleland ligaments, extending from the flexor sheath and distal phalanx volar and dorsal to the neurovascular bundles, respectively. Anatomy

Arterial supply of the fingertip  The digital arteries and nerve trifurcate near the distal interphalangeal joint.  The proper digital artery crosses the distal interphalangeal joint, sending a branch to the nail fold, nail bed, and finger pad

Venous drainage of the fingertip

Innervation of the fingertip  Each digital nerve trifurcates near the distal interphalangeal joint, sending branches to the perionychium, fingertip, and volar pad.  The digital nerves lie volar to the digital arteries near the fingertip.  The fingertip is the organ of touch and feel and is abundantly supplied with sensory receptors, including Pacinian and Meissner corpuscles and Merkel cell neurite complexes.

Nail Physiology and anatomy  The dorsal surface of the fingertip comprises the nail fold, nail bed, and nail plate (= perionychium).  The perionychium includes the entire nail bed and paronychium complex.  The paronychium is the skin surrounding the nail plate radially and ulnarly.  The eponychium is the epidermal shelf at the base of the nail.  The lunula is the white semicircle at the base of the nail bed. The fingernail is a specialized epidermal structure, like hair.

Nailbed production  The proximal one third of the nailbed, from the nail fold to the edge of the lunula, is the germinal matrix. It has two components, the dorsal and intermediate nail. The two thirds of the nailbed distal to the lunula is the sterile matrix or ventral nail.  Fingernail production occurs in 3 areas of the nailbed, the dorsal nail and intermediate nail of the germinal matrix and the ventral nail of the sterile matrix. Of these areas the intermediate germinal matrix produces 90% of nail volume. The remainder of the nail substance is produced by dorsal nail of the germinal matrix and ventral nail of the sterile matrix.

Nail growth rates  The dorsal roof of the germinal matrix deposits cells on the nail surface.  The two thirds of the nail bed distal to the lunula, the ventral nail or sterile matrix, acts as a conveyor belt for the advancing nail and adds squamous cells to the nail, making it thicker and stronger (Zook, 1994).  The nail is not merely attached to the bed but rather is a continuum of a single structure from basilar cells in the nail bed.  Nail growth occurs at a rate of 3-4 mm a month. It takes 3-4 months for growth to full nail length and 1 year for the nail to achieve maximal pre-injury smoothness.

Local Flaps  Flap tissue is attached temporarily or permanently to its donor site by a pedicle through which vascularisation is maintained  Beasley cites 3 indications of flap coverage Unsuitable for revascularisation with a skin graft Subcutaneous as well as skin replacement Protection is required of an exposed vital structure eg nerve,joint  Flaps can be local, regional and distant

Fingertip injury assessment  Level of injury  Mechanism  Depth of loss  Exposed bone/tendon  Nailbed support  Contamination  Patient factors

Local flap options for fingertips  When bone or tendon is exposed at the base of a fingertip wound, a local flap is required.  The various local flaps used to reconstruct fingertips include volar V-Y, bilateral V-Y flaps, cross-finger flap, thenar flap, and island flaps.  Flap choice depends on orientation and configuration of the wound, injured finger, and sex of the patient.  Surgeons can optimize the reliability of these local flaps by avoiding tension on the suture line and preserving the traversing sub-dermal blood vessels into the flap

Volar V-Y flap  Though frequently termed the Atasoy flap, Tranquilli-Leali first described the volar V-Y flap in 1935 (Atasoy 1970).  The volar V-Y flap is a triangular-shaped volar advancement flap outlined with its tip at the distal interphalangeal crease.  The local flap is most applicable for transverse and dorsal avulsions when a relative abundance of pulp skin is present  Then the V is scored through the dermis only to avoid injuring the traversing vessels into the triangular-shaped flap

Bilateral V-Y flaps The disadvantages of Kutler flaps include partial or complete flap  In 1947 Kutler described the bilateral V-Y flaps for fingertip injuries.  Best applied for volar and transverse avulsions with exposed bone when excess lateral skin is present.  These flaps are designed along the midlateral line and should not extend proximal to the distal interphalangeal joint.  In raising these flaps the incisions are performed through the dermis only to preserve vessels.  The flaps are mobilized for distal advancement by dissecting fibrous septae from the distal phalanx.

The Cross Finger Flap  Originally termed the transdigital flap by Gurdin and Pangman in 1950, the cross-finger flap is commonly used for volar- directed tip injuries with exposed bone or tendon when insufficient pulp for the volar V-Y flap is present.  Requires two operations and a skin graft.  Moreover, the fingers become stiff during the delay between these two stages.

Cross finger flap technique  The flap is elevated from the adjacent finger dorsum in the plane above the peritenon to allow for grafting of the donor site.  A full-thickness graft can be taken to close the donor finger dorsum.  The flap is opened like a book cover, turned 180°, and inset into the fingertip defect. The fingers may be sutured together or even pinned to prevent flap dehiscence.  During the delay, gentle active range-of-motion exercises are critical to prevent joint stiffness of both fingers.  At 2-3 weeks the flap is divided and inset and more aggressive active and passive range-of-motion exercises are begun.

Cross finger flap results  Cohen and Cronin described innervated cross finger with dorsal branch of digital nerve being divided proximally and then rejoined to digital nerve of the injured side Ie ulnar dorsal digital branch of MF to radial digital nerve of IF  Attractive theoretically, seems as over kill when standard cross-finger flaps have such good results  Kleinert and colleagues 70% have 2 point discrimination of less than 8mm  Nicolai and Hentenaar 53% had 2 point discrimination within 2mm of the same pulp in the opposite hand

Cross finger flap results  The disadvantage to the cross-finger flap is the need for a second operation and the delay that results in stiffness.  Accordingly, this flap is contraindicated for older patients or those with Dupuytren syndrome or rheumatoid arthritis.

Thenar flap  The classic description of the thenar flap by Gatewood in 1926 was proximally based (Gatewood, 1926).  Later, Smith and Albin (1976) described the H-shaped modification of the thenar flap.  A 2 cm x 4 cm thenar flap can be harvested from the MCP crease and still allow primary closure of the donor site with thumb flexion.  Care must be exercised in harvesting this thenar flap at the MCP crease to avoid injury to the neurovascular bundles and flexor pollicis longus tendon (Russell, 1981).

Laterally based pedicled flaps  An alternative way to increase the pulp advancement for more oblique palmar sloping defects is to use single pedicle lateral flaps. The earliest of these lateral flaps was described by Geissendörfer in This flap was subsequently popularised by Kutler.  It is vascularised by the small vessels beyond the trifurcation of the digital arteries.  Do these flaps ever move as much as in the drawings in textbooks?

Segmüller & Venkataswami flaps  In 1976, Segmuller described a variant of the Kutler flap that is elevated on the neurovascular bundle  Each lateral flap is raised as an island on its own neurovascular bundle and has a much bigger volume and reconstructive potential than the Kutler flaps. Up to 20mm  Originally, Segmüller raised the flaps only as far proximally as the DIP joint crease. Lanzetta et al described the use of a modification in which the flap is extended back to the PIP joint.

Segmüller & Venkataswami flaps  The Segmüller flap can also be bilateral and carries its own innervation while the advancing edge of the Venkataswami flap furthest from the pedicle is denervated.  Venkataswami then described an oblique triangular flap based on the contralateral neurovascular bundle for oblique dorsolateral tip amputations

Segmüller & Venkataswami flaps 

Moberg Flap  Rectangular volar advancement flap  Though often termed the Moberg flap, the volar advancement flap was first described by Littler in 1956 before being popularized by Moberg in  This is a rectangular volar flap based on both neurovascular bundles.  The flap is undermined in the distal to proximal direction to the MCP crease superficial to the flexor pollicis sheath and advanced in the distal direction. This flap can usually be advanced mm distally.

Moberg flaps  Raised on both neurovascular pedicles, it has excellent sensation and vascularity  Midaxial incisions are made bilaterally, just dorsal to the neurovascular bundles, both of which will be raised with the flap  However, this flap can be used reliably only in the thumb, where an independent dorsal blood supply guards against necrosis of the dorsal skin.

Axial Flag Flap  Based on web space of donor finger  Dorsal MCA is reliably present in the 2 nd interspace (less so in others)  Pedicle need only be as wide as the vessel therefore increased mobility

An axial-based “flag flap” named for its configuration. The designed narrow pedicle allows for great mobility of the flap

Kite Flaps (1 st Dorsal MCA)  Island pedicle flap proximally based on the first dorsal metacarpal artery and veins.  Courses over 1 st dorsal interosseous muscle from the radial artery as it courses distal to snuffbox (doppler pre-elevation) Can be sensory with branches of superficial radial nerve  Fascia carefully lifted off the DI muscle  Can also be distally based on perforators near radial base of 2 nd metacaroal

Quaba Flap(1990)  Distally based dorsal hand flap  Perforators consistently present cm proximal to MCPJ through intermetacarpal spaces of 2-4 distal to intertendinous connecitons

Other Flaps  Regional Radial forearm Ulnar forearm PIN  Distant Groin  Free flaps