Surgery for idiopathic megarectum and megacolon

Abstract

Many patients with IMM can be managed successfully with laxatives. In a few surgery is required. A subtotal colectomy with ileorectal anastomosis is the operation of choice if the bowel is not too dilated, with a good outcome in approximately 80% of patients. In those with a grossly dilated rectum, a Duhamel procedure is a reasonable alternative, but the results are not as satisfactory. A left iliac colostomy formed above the dilated bowel is an acceptable option for those patients happy to live with a stoma. Distal resection with coloanal anastomosis, or restorative proctocolectomy, are experimental procedures whose roles are yet to be defined. The selection of the right operation for the right patient depends on a very careful evaluation. This should include a psychological assessment, as many patients have intellectual, social or psychological problems. The upper gastrointestinal tract should be evaluated by at least a barium meal and follow through, to try and exclude patients who have idiopathic intestinal pseudo-obstruction. The anal sphincter should be assessed physiologically to detect those with a weak sphincter, in case diarrhoea or worsened incontinence supervenes postoperatively. Because these patients are uncommon and difficult to assess, they should be man-aged by practitioners with a special interest in the condition.