Background and objective: We previously showed that approximately 10% of patients with intractable constipation have spinal abnormalities without any other physical findings. Given that spinal magnetic resonance imaging is costly and often requires deep sedation in children, it would be useful to find a screening tool to determine who has a higher likelihood of having a spinal abnormality. The aim of the study was to determine whether anorectal manometry is a useful screening test in predicting which patients will have abnormal spinal MRIs.
Patients and methods: This is a case-control study comparing the anorectal manometries of 10 children with constipation who had abnormal spinal MRIs (cases) to the manometries of 10 age-matched children with normal MRIs (controls).
Results: The maximum relaxation of the sphincter after balloon distention was achieved with a significantly smaller balloon in the cases as compared with the controls (35 ± 20 vs 60 ± 23 mL; P = 0.02). The dose-response curve of sphincter relaxation at different balloon distention was shifted to the left in patients with spinal lesions. Anal spasms after balloon distention were noted in 60% of the patients with abnormal magnetic resonance images compared with 0% of the controls (P < 0.003). There were no other differences.
Conclusions: Patients with spinal cord abnormalities may show changes in anorectal manometry. Anal spasms on anorectal manometry are significant predictors of spinal abnormalities. Also, patients with spinal abnormalities have maximum sphincter relaxations with smaller balloon sizes. Further studies are needed to determine the utility of anorectal manometry as a screening test for spinal abnormalities in patients with constipation.