Motility and sensation of the rectosigmoid and the rectum in patients with anorectal malformations.

Motility of the rectosigmoid and rectum and reservoir function of the rectum after surgery for anorectal malformations were investigated in 32 patients (17 with high type, 6 with intermediate type, and 9 with low type anomaly) aged 5 to 16 years. All 32 patients were examined manometrically as well as with a newly devised myoelectrical method. Manometry showed that the values of maximum anal pressure and anorectal pressure difference in the high type were significantly lower than those in the low type. However, the incidence of contractile activity of the rectosigmoid was not significantly different between these two groups. The threshold sensation pressure and the maximum tolerable pressure in the high type were significantly higher than those in the low type, and the rectal compliance in the high type was significantly lower than that in the low type. Electromyography was recorded at 8 cm and 5 cm from the anal verge. Two types of slow waves were observed, a faster rhythm and a slower rhythm. Their frequency was similar in the three groups. However, the numbers of spike bursts in the high type and intermediate type were significantly higher than those in the low type. These results indicate that in addition to an inadequate anal resting pressure a loss of optimal rectal sensation or rectal reservoir function might be associated with fecal incontinence in the high type and that increased spike bursts might play some role in rectal motility.