Anorectal functions in patients with lumbosacral spinal cord injury

To investigate the anorectal status in patients with lumbosacral spinal cord injury (SCI).

Twenty six patients (23 males, 3 females) with lumbosacral SCI and 13 normal volunteers were enrolled into this study as controls. The median age was 43.7 years (ranging 17-68 years) and the median time of patients since injury was 59.1 months (ranging 8 months-15 years). They were diagnosed as complete lumbosacral SCI (n =2, American Spinal Injury Association (ASIA) score A), or incomplete lumbosacral SCI (n=24, ASIA score B-D) with mixed symptoms of constipation and/or fecal incontinence, and were studied by anorectal manometry. None of the patients had any medical treatments for neurogenic bowel prior to this study.

The maximum anal resting pressure in lumbosacral SCI patients group was slightly lower than that in control group (One-way ANOVA: P=0.939). During defecatory maneuvers, 23 of 26 (88.5%) patients with lumbosacral SCI and 1 of 13 (7.7%) in the control group showed pelvic floor dysfunction (PFD) (Fisher's exact test: P<0.0001). Rectoanal inhibitory reflex (RAIR) was identified in both patients with lumbosacral SCI and the controls. The rectal volume for sustained relaxation of the anal sphincter tone in lumbosacral SCI patients group was significantly higher than that in the control group (Independent-Samples t test: P<0.0001). The mean rectal volume to generate the first sensation was 92.7 ml+/-57.1 ml in SCI patients, 41.5 ml+/-13.4 ml in the control group (Independent-Samples t test: P<0.0001).

Most of the patients with lumbosacral SCI show PFD during defecatory maneuvers and their rectal sensation functions are severely damaged. Some patients exhibit abnormal cough reflex. Anorectal manometry may be helpful to find the unidentified supraconal lesions. RAIR may be modulated by central nervous system (CNS).