Rectal hyposensitivity for non-noxious stimuli, postprandial hypersensitivity and its correlation with symptoms in complete spinal cord injury with neurogenic bowel dysfunction.

Study Design: Prospective clinical study.
Objectives: To assess fasting and postprandial (PP) perception of rectal distension and its correlation with symptoms in patients with spinal cord injury (SCI) and neurogenic bowel dysfunction compared to ten healthy subjects (HS).
Setting: Experimental Medicine and Motility Unit, Mexico General Hospital and National Institute of Rehabilitation.
Methods: Twenty patients with complete SCI at cervical, thoracic and lumbar levels [American Spinal Injury Association (ASIA) A] were studied. Rectal sensitivity was evaluated with a barostat.
Results: In SCI patients, while lower the rectal tone more time was used for defecate (R=0.50, P=0.048) and more PP episodes of fecal incontinence occur (R=0.54, P=0.030). The thresholds for non-noxious stimuli of first (23.6 mmHg, CI 19.5-27.7) vs 14.0 (CI 10.9-17.1), P=0.004; gas (27.9 mmHg, CI 19.9-35.8) vs 17.9 mmHg (CI 14.25-21.69), P=0.02 and urge-to-defecate sensation (33.2 mmHg, CI 27.5-38.8) vs 22.4 mmHg (CI 17.9-26.9), P=0.01 were reported by SCI patients at higher pressure than HS, respectively. SCI patients reported PP pain sensation at a lower pressure than controls (27.8 mmHg, CI 21.5-34.2 vs 36.5 mmHg, CI 31.8-41.2), P=0.04.
Conclusion: SCI patients preserve rectal sensation, present rectal hyposensitivity for non-noxious stimuli and PP hypersensitivity. Lower rectal tone was related to the time used for defecate and with fecal incontinence. The results suggest that an intact neural transmission between the spinal cord and higher centres is indispensable for noxious stimulus, but not for non-noxious stimuli. Also, barostat sensitivity studies can complement ASIA criteria to verify a complete injury.