Anorectal manovolumetry in the decision making before surgery for slow transit constipation

Colectomy with ileorectal anastomosis for slow transit constipation (STC) is being challenged by other operations, such as segmental resections. The importance of preoperative anorectal physiology testing may therefore be increased. The aim of this study was to identify anorectal abnormalities in patients with STC, which may influence the surgical approach.

Fifty consecutive patients with STC (43 women; median age, 49 years) and 28 controls (23 women; median age, 50 years) were examined with anorectal manovolumetry. Anal pressures and rectal volumes were recorded, at stepwise rectal distension.

Anal resting pressure was lower in patients (median, 54 cm H(2)O; range, 22-130) than in controls (median, 68 cm H(2)O; range, 35-100) (p<0.05). Squeeze pressure tended to be lower in patients (median, 147 cm H(2)O; range, 53-382) than in controls (median, 177 cm H(2)O; range, 65-423) (p=0.09). Rectal sensory thresholds did not differ significantly between patients and controls, although 10 patients had a threshold for filling above the 95(th) percentile of controls. Rectal compliance was increased in patients in the pressure interval 5-35 cm H(2)O (p<0.05-0.01). The threshold and amplitude of the recto-anal inhibitory reflex did not differ significantly, but the recovery of resting pressure after eliciting the reflex was lower in patients than in controls in the pressure interval 10-50 cm H(2)O (p<0.05-0.001).

More than half of the patients with STC deviated in some parameter. An impaired internal sphincter function and increased rectal compliance were seen. One fifth of the patients had impaired rectal sensation.