THE TETHERED SPINAL-CORD IN PATIENTS WITH ANORECTAL-MALFORMATIONS

The aims of this study were to find the prevalence of tethered cord in patients with anorectal malformations; to determine if the presence o f tethered cord relates to the severity of the anorectal defect, and t o certain symptoms, signs, radiologic findings, and associated anomali es; and finally to determine whether tethered cord impacted an a patie nt's functional prognosis and whether surgical untethering improved th e patient. The authors studied 934 patients with anorectal malformatio ns, 111 of whom had magnetic resonance imaging (MRI) of the spine. We compared patients with and without tethered cord by rising parametric and nonparametric statistical tests. Tethered cord occurred in 24% of the patients. The prevalence varied according to the type of anorectal defect from 43% in the complex group to 11% in patients with rectoves tibular fistula. Patients with tethered cord had a lateral sacral rati o lower than that of patients without tethered cord (0.410 versus 0.70 2). Tethered cord was present in 90% of patients with myelodysplasia, 60% of patients with a presacral mass, 57% of patients with sacral hem ivertebrae, and 56% of patients with a single kidney. The greater numb er of associated anomalies a patient had, the greater the risk of havi ng tethered cord (P < .05 for all differences). The authors noted diff erences between patients with and without tethered cord in the presenc e of voluntary bower movements (46% versus 70%), fecal soiling (91% Ve rsus 63%), constipation (21% versus 43%), and urinary incontinence (86 % versus 42%). The data indicate that patients with tethered cord have a worse functional prognosis than patients without tethered cord. How ever, the incontinence in our patients was also predictable based on t he type of anorectal defect and the character of the sacrum irrespecti ve of the presence of tethered cord. Eighteen patients underwent surgi cal untethering of the cord, and none had any significant change in bo wel or urinary function postoperatively. No patient with tethered cord experienced incontinence that could be attributed to the cord defect alone. This study suggests that tethered cord occurs more frequently i n patients with severe anorectal defects, sacral hypodevelopment, myel odysplasia, presacral mass, sacral hemivertebrae, or a single kidney, or in those with an anorectal defect with poor functional prognosis. A t present no solid evidence supports the concept that tethered cord by itself affects the functional prognosis of patients with anorectal ma lformations. Also, there is no good evidence demonstrating that surgic al untethering improves the prognosis. Copyright (C) 1997 by W.B. Saun ders Company.