Anal sphincteric pressure studies in complete rectal prolapse.

Anal sphincteric pressure studies of patients with complete rectal prolapse demonstrated that: 1) The resting yield pressure of the internal anal sphincter in patients with complete rectal prolapse was not significantly different from that of control subjects. Thus, it seems to have no role in the etiology of prolapse. 2) The maximal sphincteric pressure of the external anal sphincter was significantly less in patients with prolapse than in controls. This suggested weakness in the effective functional power of the external anal sphincter in complete prolapse. 3) Anal continence could be achieved by the ability to maintain full contraction of the external anal sphincter for more than 40 seconds, which was the minimum for control subjects. Incontinent patients could not do this.