An Overview Algorithm for Perforator Free Flap Coverage of all Zones of the Mangled Upper Extremity

Abstract

A truly mangled upper extremity will undoubtedly need composite tissue rearrangement to ensure adequate wound healing; but often also the replacement of missing parts, always with the goal of maximizing functional rehabilitation. Whatever the approach, restoration of the cutaneous envelope surrounding the underlying repaired musculoskeletal system will be mandatory. Vascularized tissues as flaps frequently will be essential to accomplish this goal; however, intrinsic local donor sites not only may not be available due to the injury itself or if chosen would contribute to further injury. Instead, microvascular tissue transfers will play an important role. In this regard, the perforator free flap today has gained prominence as "like can replace like," sensibility is restored, secondary procedures are more simply approached, and donor site morbidity is reduced since no muscle needs to be sacrificed, maximizing function preservation. However, perforator flap donor sites are highly variable, providing another attribute that, on selection, may best meet the requirements for the involved zone of the upper extremity.

Keywords: Mangled upper extremity; Perforator free flaps; Upper-extremity zones.

Figure 1

A What exactly is a “mangled upper extremity” may be hard to define, but when you see it, you know it. Just so this amputation of the right upper extremity. The humerus and glenohumeral joint remained intact, with extensive remaining local muscle tearing and destruction. The distal fractured radius was avulsed with the degloved forearm and hand, from which the entire ulna and ulnar artery had also been torn away. The proximal radial artery in the amputated part had thrombosed but distally appeared uninjured as was the superficial palmar arch. B A forearm fillet seemed prudent as a salvage replant, retaining also the dorsal hand and palm [arrow] planned to cover the humeral stump with more durable glabrous tissues. The radial artery (A) was anastomosed end-to-end to the axillary artery at the shoulder, and a subcutaneous vein (SV) as well as cephalic vein (CV) end-to-end to each of the axillary venae comitantes. C This conjoined radial forearm flap completely resurfaced the bare humerus [arrow] to protect the glenohumeral joint. Skin grafts from discarded arm skin were placed on remaining exposed deltoid soft tissues. D This young man when last seen was able to pitch a baseball while holding a glove with his fitted prosthesis.

Figure 2

Theoretical zones of the upper extremity based on anatomical location and intrinsic local flap alternatives for potential coverage (modified from Hallock GG⁹).

Figure 3

The “expanded zone” concept respects no rigid anatomical boundaries. Flap selection instead should be determined by considering similarities in soft-tissue prerequisites as well as concomitant functional demands for the given upper-extremity location (regions with similar requirements are designated by the same color).

Figure 4

A Emergency room view of mangled upper extremity with bone exposure extending from proximal right forearm to arm. B Extremely large anterolateral thigh (ALT) flap was chosen to cover all three violated zones. C Row of perforators (p) intentionally kept in sequence with this ALT free flap to better insure total perfusion. Lateral circumflex femoral descending branch (LCFDB) artery was anastomosed end-to-side to the brachial artery, and veins end-to-end to the brachial venae comitantes. D Salvaged upper extremity, followed a year later with multiple tendon transfers to restore wrist and digit extension.

Figure 5

A Extensive radial left wrist debridement defect with exposure of multiple flexor tendons. Vessel loop around radial artery that was to be used as arterial recipient site. B Relatively thin medial sural artery perforator (MSAP) flap seen in situ overlying medial gastrocnemius (MG) muscle. Arrow points to microgrid under medial sural vascular (MSV) pedicle of the flap. C Reasonably thin MSAP free flap based on a solitary perforator. D Medial sural artery was anastomosed end-to-side to the chosen radial artery, whereas veins were anastomosed in end-to-end fashion to the larger radial vena comitante and the cephalic vein. MSAP coverage allowed unimpeded digit and wrist flexion.

Figure 6

A Original nonorthoplastic approach to severe left hand crush and dorsal skin avulsion. Multiple extensor tendons were initially repaired with plate fixation of several metacarpal fractures. Presentation later with wide-spread soft-tissue necrosis requiring debridement, including removal of some tendons and fixation devices. B Intermediate-sized free flap was desired but also so that the donor site residue would not be obvious in this young woman. A lateral arm flap was designed about the lateral intermuscular septum drawn between the deltoid insertion and the lateral epicondyle of the humerus, which so chosen would restrict all surgical morbidity to the ipsilateral upper extremity. C Lateral arm free flap based on septocutaneous perforators from the posterior radial collateral vessels (PRCV). The flap artery was anastomosed in end-to-side fashion to the radial artery, and a single vein end-to-end to the larger radial vena comitante. D Initial skin healing was accomplished, but a year later, the orthopedic service performed a thumb carpal-metacarpal joint arthrodesis to treat an adduction contracture. Coverage of the accrued widened first web space was achieved using the thin, glabrous tissues from a medial plantar artery perforator flap (arrow).

Figure 7

A universal solution if only cutaneous coverage is needed of all upper-extremity zones following a “mangling” injury, if applicable, can be a perforator free flap.