The aetiology of idiopathic megarectum is unknown and the results of surgery are often unsatisfactory. Rectal hyposensation is common and poor perception of rectal filling may contribute to the poor evacuatory function. By reducing the capacity of the rectum, it was hypothesized that sensory thresholds to rectal distension and perception of urge to defaecate would be improved.


Vertical reduction rectoplasty (VRR) and concomitant sigmoid colectomy was performed on six patients with idiopathic megarectum. Patients were evaluated before and after operation by detailed questionnaire and anorectal physiology. Postoperative rectal compliance was also studied by means of a programmable electronic barostat. Where appropriate, physiological data were compared with those obtained in eight healthy volunteers.


Bowel frequency increased from a preoperative median of 2·5 to 16 per month after operation. Four patients reported improved rectal perception of the urge to defaecate. Thresholds for defaecatory urge and maximum tolerated volume were significantly reduced following VRR (P < 0·05). Post-VRR rectal compliance was no different from that in healthy volunteers. Colonic transit time decreased significantly after VRR (P < 0·05) and evacuation on proctography increased from a median of 30 per cent to 50 per cent. At a median of 57 weeks' follow-up five of the six patients expressed continued satisfaction with the results.


VRR is a new approach to the treatment of idiopathic megarectum. Clinical and physiological studies confirm that it can improve sensory feedback and defaecation. The procedure needs further evaluation as the number of patients undergoing the procedure increases. © 2000 British Journal of Surgery Society Ltd