Ring avulsion replantation by extended debridement of the avulsed digital artery and interposition with long venous grafts.

Ring avulsion replantation is a technically challenging procedure with a very low success rate. Because the zone of arterial injury is more extensive than what it appears to be in such avulsion amputations, a technique was developed to debride the avulsed digital artery for a long distance, extending well into the digital pulp, thereby creating healthy arterial ends to be bridged by one or two segments of long venous grafts. Using this technical approach, 7 patients with complete amputations of ring avulsion injury (Urbaniak's class III) were operated. In all amputations the bone was disrupted at the distal interphalangeal level (except in 1 patient) and the soft tissues at the proximal phalanx level, with the proximal interphalangeal joint and the flexor digitorum superficialis tendons being intact. Results indicated that replantation was successful in all patients. However, 2 patients presented with unusually late arterial failure 28 and 30 days after surgery respectively. Although one of these cases was salvaged by reoperation, the other case (followed by conservative management) demonstrated partial distal necrosis. Therefore, the ultimate success rate in this series was 85% in the long term. At follow-up, sensibility was protective in all patients, with an average static two-point discrimination of 7.8 mm (range, 6-14 mm). The total active motion of the replanted digits was 194 deg on average (range, 155-205 deg) without loss of function of the proximal interphalangeal joint except in 2 patients who had late vascular problems. The authors conclude that microsurgical replantation of completely amputated ring avulsion injuries with an intact proximal interphalangeal joint and flexor digitorum superficialis tendon, is a worthwhile procedure that results in good functional and aesthetic results. Furthermore, using an aggressive approach for debridement of the avulsed digital artery, as described in this article, an experienced microsurgeon can replant successfully nearly all cases. However, one should be cautious in the follow-up of such patients, because late arterial failure may be encountered, as was observed in 2 patients in this series. The authors suggest immediate reoperation in such unusual circumstances.