Filum Section for Urinary Incontinence in Children with Occult Tethered Cord Syndrome: A Randomized, Controlled Pilot Study

Abstract

Occult tethered cord syndrome, in which there is normal neuroanatomic imaging despite clinical and urodynamic evidence of neuropathic bladder behavior, is controversial. Several uncontrolled series describe improvement in bladder function following section of the filum terminale. We performed a pilot randomized, controlled study comparing medical treatment to surgical section of the filum plus medical treatment in children with occult tethered cord syndrome. Children refractory to standard medical management for 1 year or more with normal conus position on magnetic resonance imaging and abnormal urodynamics were randomized. Exclusion criteria included any neurological conditions, spinal dysraphism, bladder outlet obstruction and an atonic bladder. Patients were assessed at randomization and 1 year later with a standardized urodynamic score, the validated PEMQOL (Pediatric Enuresis Module on Quality of Life™) scale, and a validated bowel and bladder dysfunction score. After 8 years we accrued 21 patients. The bowel and bladder dysfunction score improved in the surgical and medical arms (20% and 24%) and the urodynamic score improved slightly (6% and 4%, respectively). The PEMQOL Child and Family Impact Scales improved modestly in both groups. All differences were nonsignificant. Interim analysis indicated that more than 700 patients in each arm would be required to demonstrate a statistical difference with respect to urodynamic score based on our preliminary data. There appears to be no objective difference in urological outcome between medical management plus or minus filum section for patients with occult tethered cord syndrome. These data challenge the existence of the concept of occult tethered cord syndrome, in which bowel and bladder dysfunction score is attributed to tethering by the filum despite a normally located conus.