[Sphincter-preserving surgery: per anal coloanal anastomosis]

Since the introduction of the stapling technique, sphincter-preserving surgery for treatment of rectosigmoid and upper rectum carcinoma has been widely performed in the view of its radicality and postoperative quality of life. Sphincter preservation is still controversial in carcinoma of the lower rectum. Since we introduced per anal coloanal anastomosis (PAA) in 1980 and per anal intersphincteric dissection and coloanal anastomosis (PIDCA) in 1993 for the treatment of lower rectal carcinoma, the sphincter has been preserved in 78.7% of patients. There was no significant difference in the 5-year survival rate between patients in whom the sphincter was preserved and those who underwent abdominoperineal resection during the same period. PAA and PIDCA are safe when anastomosis must be performed at the dentate line. They are the best sphincter-preserving techniques for lower rectal carcinoma and do not result in serious postoperative dysfunction.