[Animal experimental studies of the smooth muscle pedicle flap (tunnel graft) in the goat].

Anorectal smooth muscles pedicle flaps (funnel grafts) according to the dragging method described by Holschneider in 1980, 1981 and Hofmann-von Kap-herr and Koltai 1981 were performed on 20 Syrian goats and German pedigree goats. Postoperatively, three animals died because of pulmonary infection with worms; 17 animals could be examined. Six of these 17 animals died during the postoperative follow-up period from the sequels of the operation. In five animals the cause of death was prestretching of the transplant by 150 and 200%; three of these developed severe enterocolitis, whereas two had stenosis and ileus, resulting in death in each case. In addition, five further animals showed signs of enterocolitis; eight goats had constipation which in every case could be ascribed to prestretching of the transplant by 150% and more. These animals had to be treated by infusion and bouginage, leading to recession of the signs after four to six days. Electromanometrically an increased anorectal resting pressure profile was found postoperatively in all cases, i.e. even if the transplant was prestretched to tension values of only over 100%. Relaxations of the internal anal sphincter could be achieved in all animals; however, in goats with a transplant stretch of 150% and more they were observed only after the resting pressure profile had receded, a few months after the operation. Histologically, there was increasing fibrosis and disintegration of the transplant in all animals with more than 150% prestretch. With 200% prestretch, the plexus myentericus disintegrated also, so that no relaxation could be achieved. Basing on these clinical, manometrical and histological results, smooth muscle transposition (funnel graft) can be recommended to improve continence in infants by employing the dragging method according to Rehbein-Romualdi. However, prestretching of the transplanted pedicle flap should not exceed 120-140%.