Purpose: To evaluate in children and infants with imperforate anus the prevalence and types of occult myelodysplasia that may result in tethered cord and the association of these lesions with vertebral anomalies.
Materials and methods: Records and images were retrospectively reviewed in 86 patients who underwent spine magnetic resonance imaging and had either low-level imperforate anus (n = 30), intermediate-level imperforate anus (n = 15), or high-level imperforate anus (n = 41).
Results: Thirty-one of 86 patients (36%) had occult myelodysplasia suggestive of tethered cord (27% of all patients with low-, 33% of all patients with intermediate-, and 44% of all patients with high-level lesions). Of these 31 patients, 16(52%) were asymptomatic, 24, (77%) had a thickened fatty filum, 13 (42%) had normal conus position, and 23 (74%) had vertebral anomalies. Twenty-four of the 31 patients (77%) underwent surgical untethering.
Conclusion: A substantial number of patients with all types of imperforate anus have occult myelodysplasia that may necessitate surgical intervention, including those patients with normal spine radiographs.