A 47-year-old male patient sustained a crushing amputation of the left thumb by agricultural machine. The distal phalangeal bone was segmentally fractured and two attempts of reanastomosis of the ulnar digital artery were not successful. On the seventh postoperative day, the necrotic thumb was debrided (▶Fig. 60.1).
The patient has a distal thumb amputation through the base of the distal phalanx. The thumb requires soft tissue coverage for exposed phalangeal bone as well as length for restoration of key pinch and grip.
There are a number of options for this patient. The goals are to provide sensate stable coverage and added length to restore optimal function and form. The wounds could be dressed with a Vaseline dressing and allowed to heal by secondary intent. This would take a number of weeks and still not address the short thumb problem A revision amputation would shorten the bone even more, but would offer glabrous skin coverage with sensation and have the least amount of down time for the patient. Thoracoepigastric flaps do not offer sensation. Local flaps from perforators from the digital arteries can be propelled from the proximal thumb to the distal thumb and offer stable coverage, but again thumb length has not been addressed and the distal end remains insensate. The first dorsal metacarpal artery flap can also provide stable, sensate coverage but does not address thumb lengthening.
An optimal solution to this problem would be to use the great toe as a toe-to-hand transfer offer restoration of sensation and thumb length.
The great toe flap is designed first by measuring the contralateral thumb to be accurate with the required length of toe needed to restore normal anatomy (▶Fig. 60.2).
Using a retrograde approach on the first web space of the foot, the dominant artery should be dissected from the first web space to the proximal direction. In this case, the first plantar metatarsal artery is dominant and extension incision on the plantar area is necessary. The artery is skeletonized by a radical resection of adventitia and the vein is dissected with the perivenous tissues (▶Fig. 60.3).
Fig. 60.1 (a–c) A failed distal thumb replantation resulted in a revision amputation with soft-tissue loss to the volar skin and a bone loss at the level of the base of the distal phalanx.
Fig. 60.3 The dissection is initiated in the first web space to identify the dominant artery system being either dorsal or plantar.
Digital nerves of the great toe are also harvested to coapt with the corresponding structures of the thumb. The venous network on the medial aspect of the great toe is more reliable than the first web space. There are always prominent branches of the great saphenous vein proximal to the medial nail fold on the tibial aspect of the great toe. This vein should be included in the flap to prevent necrosis of the remnant skin flap. On the dorsum side of the great toe, the subdermal venous plexus should be preserved to close the donor site (▶Fig. 60.4).
Partial great toe from the left foot was transferred after disarticulation at the interphalangeal joint (▶Fig. 60.5).
After arthrodesis of the interphalangeal joint of the thumb with two or three Kirschner’s wires, arterial anastomosis was performed between the first palmar metatarsal artery and the princeps pollicis artery at the first web space of the dorsum. When the arterial anastomosis is performed at the anatomical snuffbox, a subcutaneous tunnel is made by intraoperative expansion with a Nelaton catheter or silastic drain between two incisions for passage of the vascular pedicle. This helps avoid the scarring caused by a long incision and the necessity to perform a skin graft on the reconstructed thumb. Venous anastomosis is performed with a superficial vein at the dorsal aspect of the thumb.
In management of the donor site, primary closure without tension is preferred. If needed, a cross-toe flap or skin graft from the plantar aspect is performed to resurface the donor defect.
Intensive postoperative monitoring of the perfusion of the transferred toe is performed for 5 to 7 days. From the third week after the operation, rehabilitation therapy is begun for restoration of sensation and Coban taping is applied to decrease edema of the transferred toe. In the seventh to eighth week after the operation, the Kirschner wires are removed. Secondary procedures such as pulp plasty, nail fold plasty, or scar revision can be carried out 3 to 6 months after surgery.