For the purpose of studying the embryology and genetics of imperforate anus, we attempted to produce this disease in a large number of swine. In the anatomical evaluation and the process of treating and raising the swines, we had various experiences on this disease. In the studies of 31 swine materials, we found a similarity to the human anomaly. In male swines there was no external perineal fistula. There were one recto-vesical fistula with severe reno-ureteral anomaly and 19 recto-urethral fistulas. In female swines, there were 3 recto-vaginal and 5 recto-vestibular fistulas. We operated on neonatal piglets, employing various methods such as colostomy, perineal and sacro-perineal operations. We finally succeeded in establishing the proper operative method. A closure of recto-urethral fistula was essential for male. Posterior saggittal approach by Pena was also employed for treatment of recto-cloacal fistula in female. In this way, swine is a suitable therapeutic model for perineal and sacro-perineal operations, including the closure of recto-urethral fistula. But the swine has no muscles identical to the pubo-rectalis and the pelvic diaphragm which are seen in the human. Therefore, it is not possible to use the swine as the model for evaluation of fecal continence. Post-operative anal stenosis occured almost always without bouginage and prolapse of the mucosa (or anus) occured very often, if a loose anus was produced. The proper operative method and management, preventing these complications were investigated.
