A 46-year-old man had a crushing injury involving the thumb and index, middle, and ring fingers of his dominant, right hand due to a power press machine accident. In an attempt to salvage the hand, the thumb was amputated at the interphalangeal joint, the index and middle fingers were amputated at the proximal phalanx, and the ring finger was amputated at the distal phalangeal tip with a proximal phalangeal fracture. In an emergency operation, wound debridement and Kirschner wire (K-wire) fixation of the index and ring fingers were performed. All the fingers were open amputated because the stump was lost. The ring finger showed arterial insufficiency, so we anastomosed both digital arteries. One week after the trauma, an angiography was performed to assess the vasculature of the injured hand and revealed an intact radial artery and its dorsal branch (Fig. 1). We subsequently performed a reconstruction using a TDAP free flap to resurface the thumb index and middle fingers. Preoperatively, the perforating artery from the thoracodorsal artery was identified with an audio Doppler machine. The perforating sites were detected, and the most reliable perforating artery was marked. The flap was designed on the basis of the most reliable perforating artery of approximately 18.0×11.0 cm in size. With the identified intermuscular perforating artery from the descending branch of the thoracodorsal artery, a 10-cm-long pedicle was harvested to cover the defect. The flap was harvested with an approximately 1.5-cm thickness by flap elevation excluding the deep adipose layer (Fig. 2). The dorsal branch of the radial artery was identified and used as the recipient artery. Vessel anastomoses were performed end-to-side between the thoracodorsal artery and the recipient artery and end-to-end between one vena comitantes and the cephalic vein. The donor site was closed directly and the flap survived without necrosis or other serious complications. We divided the thumb and the other two fingers 4 weeks later. Finally, we performed debulking and scar excision of the palmar and dorsal sides 3 months later (Fig. 3). The patient was then able to key pinch and grasp objects.

A 22-year-old man had a crushing injury involving the thumb, index, and middle fingers of his dominant, right hand due to a power press machine accident. The carpometacarpal joint of the thumb was open-dislocated with the ruptured thenar muscle. The index and middle fingers were fractured and dislocated at the metacarpophalangeal joint, and the distal portion was severely injured. We performed an open reduction and internal fixation with a K-wire of the dislocated carpometacarpal joint of the thumb. The index and middle fingers were amputated because replantation was impossible because of the severely injured status. Then, the thumb showed arterial insufficiency, so we performed microsurgery of the end-to-end anastomosis of princeps pollicis artery to the second common digital artery. The princeps pollicis artery showed an anatomical variation, so it was difficult to identify. Usually, the dorsal branch of the radial artery makes its way into the deep palmar arch by passing through the gap between the first and second metacarpals. The deep palmar arch gives rise to the princeps pollicis artery, which is the main supply artery of the thumb. Therefore, microsurgery for the princeps pollicis artery could be performed on the volar side between the first and second metacarpals. However, in this case, princeps pollicis artery arose directly from the dorsal branch of the radial artery. Then, the dorsal branch of the radial artery passed through under the thumb flexor and A1 pulley. We cut the princeps pollicis artery at the metacarpal area and performed an end-to-end anastomosis to the second common digital artery (Fig. 4). In addition, the ulnar digital artery of the thumb from the index digital artery was not identified. Therefore, anastomosis of princeps pollicis artery is crucial for the survival of the thumb. Partial necrosis of the index and middle metacarpal area developed, so we performed a debridement 4 weeks later. We subsequently used a TDAP free flap for coverage of the thumb, index, and middle fingers. A 15.0×7.0-cm flap was harvested using the same technique in the above-mentioned case. The flap was harvested under a 1-cm thickness by flap elevation, excluding the deep adipose layer. Vessel anastomoses were performed end-to-side between the thoracodorsal artery and the recipient artery and end-to-end between one vena comitantes and the cephalic vein. Postoperative recovery was successful and the flap survived completely. Finally, we performed debulking and a Z-plasty procedure 3 months later (Fig. 5). The patient was able to key pinch and grasp objects with a thin flap.

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