Screening and Treatment of Tethered Spinal Cord in Anorectal Malformation Patients

This study aims to evaluate diagnosis and treatment of tethered spinal cord (TSC) in anorectal malformation (ARM) patients.

A retrospective case study was performed on patients with an ARM born between 2004 and 2011 and treated at the Erasmus MC-Sophia Children's Hospital.

During the study period, 110 neonates with ARM were treated. Spinal ultrasonography was performed in 94 (85%) patients. Ultrasonography findings were abnormal in 17 patients (18%): 16 had evidence for TSC and 1 for caudal regression. These findings were confirmed by magnetic resonance imaging (MRI) in eight patients. Six of the other 76 patients developed neurologic symptoms and MRI revealed evidence for TSC in 2 of those 6 patients. Thus, sensitivity of spinal ultrasonography was 80%, specificity was 89%, the positive predictive value was 47%, and the negative predictive value was 97%. The prevalence of TSC, as confirmed by MRI, was 9%. Three patients underwent untethering surgery: one patient developed neurologic symptoms and two patients were asymptomatic at the time of surgery (MRI showed progressive syringomyelia in one and the other had a dermal sinus with TSC). All operations were without any complications and the symptoms resolved in the first patient. A relationship between TSC and a specific type of ARM or syndrome disorder could not be found.

Tethered cord occurs in 9% of the ARM patients. Neonatal spinal ultrasonography has a sensitivity and specificity of 80 and 89%, respectively. Not in all patients an MRI was performed, but the vast majority remained clinically asymptomatic concerning TSC. Ultrasound screening seems an effective screening method, however, when ultrasonography is negative and the patient becomes symptomatic later in life, an MRI should be performed to exclude TSC. In our series, only 1 of 110 ARM patients had symptomatic tethered cord syndrome, and symptoms resolved postoperatively.