Abstract:OBJECTIVE: Compared with numerous research reports of neurogenic bladder dysfunction of spina bifida, the research on neurogenic bowel dysfunction of spina bifida is rare. This study aimed at investigating the anorectal function in children with spina bifida who underwent the spinal cord untethering procedure. METHODS: Twenty-one children with spina bifida who underwent the untethering operation for tethered cord syndrome at least 2 years ago were enrolled in this study. All patients had severe bladder dysfunction and received anorectal manometry examination. Eleven age-matched children with hypospadia served as controls. RESULTS: The maximum anal resting pressure in spina bifida patients was lower than that in controls, but the difference was not statistically significant. Most of the patients did not show an anal pressure increase during squeezing action. During defecatory maneuvers, 19 spina bifida patients(90.5%)exhibited pelvic floor dysfunction. Rectoanal inhibitory reflex was identified in both spina bifida patients and controls. The rectal volume for sustained relaxation of the anal sphincter tone was significantly higher in spina bifida patients than in controls (P<0.001). The mean rectal volume to generate the first sensation in spina bifida patients was significantly higher than that in controls (P<0.001). CONCLUSIONS: Most spina bifida patients lose the ability to voluntarily contract their external anal sphincter, presenting with pelvic floor dysfunction during straining maneuver and severe rectal sensation function damage. Rectoanal inhibitory reflex is present in all patients with spina bifida and the reflex may be modulated by central nervous system.
