A Bilobed Pedicled Groin Flap for Reconstruction of Forearm Skin Defects following Replantation.

The versatility of a pedicled groin flap can be further increased by raising it in a bilobed fashion. This allows the flap to cover both the volar and dorsal surfaces of a hand or forearm defect. A 48-year-old man sustained an avulsion amputation of his right forearm by a rolling machine in a workplace accident. Replantation of the right forearm was performed, and the postoperative course was uneventful. Unfortunately, the wound healing was complicated by circumferential marginal skin necrosis, which was confined to the distal forearm. A bilobed pedicled groin flap was performed for the wound coverage because reconstruction with a free flap would be very risky as the vessels were avulsed from the proximal part of the forearm. A good functional recovery of the hand and fingers was noted at 12 months' follow-up. The advantages of a bilobed pedicle groin flap are that it allows coverage of both the volar and dorsal surfaces at one setting and primary closure of the donor site is possible. Furthermore, a long tube-shaped pedicle in this flap can reduce the patient discomfort and prevent finger stiffness by allowing a range of motion exercise. In conclusion, the bilobed pedicled groin flap is a useful option to cover soft tissue defects involving both the volar and dorsal surfaces over the mid- to distal forearm, especially when the free flap is contraindicated.

INTRODUCTION

The pedicled groin flap was first described by McGregor and Jackson[1] in 1972. It is still a useful reconstructive tool in hand surgery nowadays, despite the advancement of surgical technique in free flaps. Pedicled groin flap can provide soft-tissue coverage for any defects on the hand and distal two-thirds of the forearm.[2] However, it is technically demanding to cover circumferential defects of the forearm and/or hand with a pedicled groin flap.[3]

As for defects involving both the dorsal and palmar hand surfaces, there were reports on wound coverage using a bilobed pedicled groin flap or a combination of pedicled groin flap and superficial inferior epigastric artery flap.[4-9] To our knowledge, there is no published literature on the utilization of a bilobed pedicled groin flap for reconstruction of the volar and dorsal forearm skin defects.

We report a case of right forearm avulsion amputation with soft tissue defects over both the volar and dorsal surfaces of forearm following replantation, of which the defects were covered successfully with a bilobed pedicled groin flap.

CASE REPORT

A 48-year-old man sustained an avulsion amputation of his right forearm in a rolling machine accident. Assessment of the injury revealed that the right radius and ulna were fractured at the distal third of the forearm, the skin was avulsed predominantly from the distal stump, and all the flexors and extensors were disrupted at the musculotendinous junction. Only the median and ulnar nerves remained intact but were elongated. Urgent replantation of the right forearm was performed with primary repair of the vessels (2 arteries and 2 veins) after shortening and fixation of the radius and ulna. We managed to repair the extensors directly, whereas the finger flexors were reconstructed by tendon transfers. The postoperative course was generally uneventful except for the occurrence of marginal skin necrosis, which was progressed gradually to involve the distal forearm circumferentially (Fig. 1). We considered several options for the soft tissue coverage, for example, free flap, a combination of pedicled abdominal and groin flaps, and bilobed groin flap. A free flap was judged to be high risk in this patient because of vascular injury over the proximal forearm (see figure, Supplemental Digital Content 1, which displays CT angiography of the right upper limb, ), whereas the combination of pedicled abdominal and groin flaps might not reach the defects due to the foreshortened forearm during replantation. Finally, we decided to use a bilobed pedicled groin flap for this patient. A pedicled groin flap with a size of 12 cm × 18 cm was designed and lifted up from the underlying fascia from a lateral to medial direction. The fascia over the lateral margin of the sartorius muscle was divided at the level of the anterior superior iliac spine, and blunt dissection was performed under the fascia to identify and preserve the lateral femoral cutaneous nerve. The dissection was continued till the medial border of the sartorius muscle. The sartorius fascia was harvested together with the flap to prevent damage to the superficial circumflex iliac artery, which was located superficial to the fascia. After completing the elevation, the flap lateral to the anterior superior iliac spine was split into a bilobed shape for adequate wound coverage and the proximal part of the flap was fashioned into a tubular shape. Good vascularity was observed in both lobes of the flap (see figure, Supplemental Digital Content 2, which displays the design of the flap, ) and it was inset onto both the volar and dorsal defects of the forearm (Fig. 2). The donor site was closed primarily without difficulty. The remaining wound over the dorsoulnar aspect of mid-forearm was covered with a split thickness skin graft from the right thigh. The limb was immobilized with a plaster splint and a broad rib band to protect the flap.

Fig. 1.

Circumferential marginal skin necrosis developed and progressed gradually over the distal right forearm after a successful replantation. Underlying ulna bone, flexor and extensor tendons were exposed after debridement and removal of necrotic skin.

Fig. 2.

The forearm was approximated to the ipsilateral groin where the flap was inset onto both the volar and dorsal defects of the forearm. The wound over the dorsoulnar aspect of the mid-forearm was covered with a split thickness skin graft.

RESULTS

Postoperatively, the range of motion exercise of the fingers was started as soon as the pain was tolerable (see Video 1 [online], which displays a range of motion exercise of the fingers). He was on complete bed rest before ambulation was permitted after 1 week. The entire flap survived well without any skin necrosis and it was divided after 5 weeks. In general, the pedicled groin flap can be divided safely after 3 weeks.[2] The delay of flap division in this case is because the patient was feeling unwell at the third postoperative week. Secondary reconstructive surgeries consisting of tenolysis of the extensor tendons and Sauve–Kapandji procedure, tenolysis of flexor tendons, and flap debulking were performed at 4, 6, and 10 months, respectively, after the replantation. Good functional recovery of the fingers was noted at 12 months follow-up (see Video 2 [online], which displays a good functional recovery of the fingers at 12 months follow-up).

Video 1.

Video 1 from “A bilobed pedicled groin flap for reconstruction of forearm skin defects following replantation”

Video 2.

Video 2 from “A bilobed pedicled groin flap for reconstruction of forearm skin defects following replantation”

DISCUSSION

It is not uncommon that skin necrosis occurs at the wound edges following major upper extremity replantation that required soft tissue reconstruction, especially for avulsion amputation with severe damage of the stump.[10] In an avulsion amputation, the damage of the vessels tends to be more proximal, making it difficult and unsafe to use a free flap. Thus, the distant pedicled flap would be a viable option in these cases. Conventionally, the pedicled groin flap can only cover a single surface of either the volar or dorsal defect.[1] A bilobed pedicle was designed to make the coverage of both the volar and dorsal surfaces possible.[4,5] The main advantage of this technique is that the donor site can be closed primarily, whereas the disadvantage of using a pedicled groin flap for wound coverage of the hand or fingers is that the range of motion exercise of the fingers is limited before the division of the flap. However, this is not an issue when using the flap to cover a forearm wound, where the fingers range of motion exercise is possible immediately after surgery. Furthermore, a long tube-shaped pedicle in a bilobed pedicled groin flap can improve the patient comfort level, allow the patient more motion, and ideally prevent stiffness.[9] In conclusion, the bilobed pedicled groin flap is a useful alternative other than the free flap to cover both the volar and dorsal skin defects at the level of mid to distal forearm.