Manometric analysis of anal sphincter damage after ileal pouch-anal anastomosis

A constant reduction in anal sphincter pressure follows an ileoanal pouch p rocedure for ulcerative colitis and familiar adenomatous polyposis. We anal yzed whether this reduction is more likely due to neurogenic damage or to d irect sphincter trauma. Three-dimensional vector volume manometry was perfo rmed in 75 patients prior to the ileoanal pouch procedure and 3 months ther eafter. Resting pressure was significantly reduced from 83.5 +/- 24.4 to 58 .1 +/- 18.0 mmHg and squeezing pressure from 204.7 +/- 63.3 to 173.4 +/- 50 .6 mmHg. Moreover, significant vector volume reductions were recorded posto peratively, and the asymmetry index increased significantly (resting: 11.5 +/- 4.1% to 18.4 +/- 7.4%; squeezing: 9.6 +/- 3.1 to 13.0 +/- 6.7%). Functi onal anal sphincter length at the high-pressure zone remained unchanged. Th us, there was no local damage to proximal or distal anal sphincter segments , which suggests that the postoperative impairment of sphincter function is secondary to neurogenic rather than morphological damage.