Preoperative anal sphincter high pressure zone, maximum tolerable volume, and anal mucosal electrosensitivity predict...

The aims of this study were to correlate postoperative defecatory function after low anterior resection with clinical factors and physiologic parameters and to explore the possibility of predicting early postoperative defecatory function after low anterior resection.

Thirty-two patients who underwent low anterior resection for rectal cancer were studied. Anorectal physiologic studies were performed preoperatively and six months postoperatively; maximum resting pressure, maximum squeeze pressure, length of the high pressure zone, neorectal sensory threshold, neorectal maximum tolerable volume, and anal mucosal electrosensitivity were recorded. Preoperative and postoperative defecatory function was scored between 0 (worst) and 6 (best) on the basis of bowel frequency, fecal incontinence, and urgency.

In univariate regression analyses, a longer preoperative high pressure zone and a more sensitive anal mucosa were associated with better postoperative defecatory function. Using multiple regression analysis, in which age, gender, the level of anastomosis, and preoperative physiologic parameters were examined as independent variables, a longer preoperative high pressure zone, a larger preoperative maximum tolerable volume, and lower sensory threshold of the anal canal were associated with better postoperative defecatory function. Postoperative function score was found to be predictable using the following formula: 1.47 + 0.496 x high pressure zone (cm) + 0.007 x maximum tolerable volume (ml) - 0.247 x sensory threshold (mA) of the anal canal.

Early postoperative defecatory function after low anterior resection is predictable from preoperative high pressure zone, maximum tolerable volume, and anal mucosal electrosensitivity.