Study of the unaltered in situ appendix as a native continence mechanism: cadaveric and clinical correlation

The past decade has seen intense efforts to develop the ideal pouch for use in continent diversion and bladder substitution. The aspect that has been singularly the most difficult to perfect has been the continence mechanism. In recent years much has been reported on the use of the vermiform appendix as a continence mechanism following one or more surgical manipulations. It was the aim of this study to determine whether the in situ appendix, without any surgical manipulation, could provide a native continence mechanism. Studies were carried out using (1) five cadaver subjects and (2) eight patients undergoing cystoprostatectomy in whom the distal tip of the appendix was removed and an ileocecal pouch was filled with irrigant until leakage was noted from the appendix. The pressure within the pouch at the time of leakage was defined as the appendiceal leak pressure. Mean appendiceal leak pressure was 50.6 cm H2O with a range from 21 to 86 cm H2O. These studies indicate that at the pressure being maintained in most continent pouches as constructed today, the in situ unmanipulated appendix would, in some cases, provide adequate continence. In others only minimal reinforcement is required to maintain continence.