Anorectal physiologic testing for bowel dysfunction in patients with spinal cord lesions

Bowel dysfunction is common in patients with spinal cord lesions. This study aims to determine whether there are any discriminatory findings at anorectal physiologic testing in patients with spinal cord lesions.

Twelve consecutive patients (6 females) with significant spinal cord lesions who had mixed symptoms of constipation, fecal impaction, and fecal incontinence were evaluated by perfusion manometry and pudendal nerve terminal motor latency. None of the patients had a sphincter defect as evaluated by endoanal ultrasonography.

The median age was 54 (range, 40-87) years. Eight (67 percent) of them had had traumatic spinal cord injuries. Other spinal cord lesions included spina bifida, syringomyelia, arachnoid cyst, and spinal cord ischemia after abdominal aortic aneurysm repair. In patients with spinal cord lesions, the mean (range) resting anal canal pressure and maximum squeeze anal canal pressure were 46 (10-100) mmHg and 76 (30-120) mmHg respectively compared with 62 (50-70) mmHg, and 138 (100-180) mmHg, respectively, in healthy controls. Eleven (92 percent) patients had prolonged pudendal nerve terminal motor latency (9 bilateral and 2 unilateral) whereas rectoanal inhibitory reflex was abolished in all 9 patients tested.

Spinal patients with severe bowel symptoms tended to have lower anal canal pressures than healthy controls. Pudendal netropathy and impaired rectoanal inhibitory reflex are common and may be important in the pathogenesis of bowel dysfunction in patients with spinal cord lesions.