Evacuation pouchography in the evaluation of ileoanal reservoir function.

Thirty four patients with restorative proctocolectomy and ileoanal pelvic reservoirs were studied by "evacuation pouchography" to determine why only some patients could evacuate spontaneously. The 50 per cent who were able had a significantly shorter distal segment (P less than 0.02) of mean length (8 +/- 3 cm) that filled on straining, compared with those who had to use a catheter to empty the pouch, in whom the distal segment was longer (mean 11 +/- 4 cm) and often failed to fill on straining. The longer the distal segment, the more likely it was to be angulated, causing difficulty in passage of the catheter with possible ulceration and stenosis from minor trauma. Stricturing in the distal segment was associated with minor nocturnal leakage. A short distal segment is recommended to allow spontaneous evacuation and avoid the risks of repeated catheterization.