Outcome in Patients Who Underwent Tethered Cord Release for Occult Spinal Dysraphism

Abstract

Tethered cord syndrome encompasses a group of clinical symptoms caused by abnormal spinal cord fixation. We evaluated a select cohort of patients with primary tethered cord syndrome in regard to urodynamic and clinical outcome after cord release. We retrospectively reviewed the records of patients with the diagnosis of tethered cord from May 2001 to October 2004. Patients were assessed preoperatively by standard urodynamic studies, which was repeated a mean of 6.4 months after tethered cord release. Clinical and urodynamic outcomes were analyzed. Ten male and 14 female patients 1 month to 12 years old (median age 6 years) were evaluable. Preoperatively 14 of the 24 patients with a median age of 8.1 years were toilet trained and 7 (50%) had diurnal incontinence. Constipation was noted in 10 of 24 patients (42%) and urinary tract infections developed in 6 (25%). Postoperatively only 1 patient (7%) experienced diurnal incontinence (p = 0.04). Constipation was observed in 6 patients (25%) and urinary tract infections developed in 1 (4.2%) (p = 0.29 and 0.07, respectively). Ten of the 21 children (48%) with abnormal urodynamics had normalized studies postoperatively. Ten of the 17 patients with neurogenic detrusor overactivity achieved normalization and 7 remained unchanged. Two of 3 patients with normal preoperative urodynamics had neurogenic detrusor overactivity and 1 had poor bladder compliance. Four patients with low bladder capacity and/or low compliance preoperatively did not improve. Our results suggest that tethered cord release is beneficial in terms of clinical and urodynamic outcomes. Patients with abnormal urodynamics had 48% improvement after tethered cord release. Neurogenic detrusor overactivity seems to respond better with 59% improvement in urodynamics. The level of the conus on magnetic resonance imaging did not seem to be predictive of urodynamic outcome. Patients with a normal bladder may show urodynamic deterioration postoperatively, which raises cause for concern.