Experimental free muscle transplantation to the anus using microsurgical technique--a new treatment for anal incontinence.

Abstract

Experimental free muscle transplantations to the anus with microneurovascular anastomoses were performed in twenty-one dogs as a model of new treatment for anal incontinence. After undergoing subtotal external sphincterectomy, gracilis muscles were transferred to the anus with microneurovascular anastomoses in Group I (n = 9), without microneurovascular anastomoses in Group II (n = 6), and the muscle transfers were not performed in Group III (n = 6). The mean anal canal pressures decreased to 24.4% of preoperative pressure at one month after subtotal external sphincterectomy. But at six months after muscle transplantation they restored up to 80.7% of preoperative pressure in Group I, 54.7% in Group II and the pressure did not restore in Group III (p less than 0.001 Group I vs Group II and III). Electromyographic study of the graft showed the electrical activity in six of seven dogs (85.7%) in Group I and electrical activity of the graft were not recognized in Group II at six months after transplantation. Histologic study of the graft showed the normal pattern of the muscle fibers in 75-80% of the graft in Group I, and fibrotic degeneration in most areas of the graft in Group II at six months after gracilis muscle transplantation.