Subclinical changes in bladder function in children presenting with nonurological symptoms of the tethered cord syndrome

Purpose: We evaluated the urodynamic findings in myelodysplastic children with the tethered cord syndrome without urological symptoms to determine if occult bladder changes occur or if routine preoperative urodynamic evaluation is not indicated for this select population. Materials and Methods: Preoperative and postoperative urodynamic studies were performed on children with myelodysplasia and the tethered cord syndrome between 1988 and 1994. Inclusion criteria were neurological or musculoskeletal surgical indications only, without urological status changes, radiographic confirmation of the tethered cord syndrome, and water cystometry performed preoperatively within 1 week and again postoperatively within 6 months. The parameters of interest included total bladder capacity and pressure, leak point pressure, compliance, uninhibited contractions, electromyelogram activity and sensation. Results: A total of 20 children, 11 girls and 9 boys, 2.3 to 17.3 years old were included in the study. Worsening scoliosis and lower extremity weakness were the most presentations. Urodynamic studies were conducted 1.8 days preoperatively (mean) and 104.3 days postoperatively (mean). Results were analyzed with regard to improvement or deterioration between preoperative and postoperative urodynamic studies. Of the 20 children 15 (75%) demonstrated improvement between the 2 urodynamic studies, including 10 who improved in 1 parameter (most often with resolution of uninhibited contractions), 3 in 2, 1 in 3 and 1 in 4. There were no significant postoperative changes for any of the specific parameters. Urodynamic studies identified 7 children with preoperative leak point pressures above 40 cm. water, of whom only 2 had decreased pressures below 40 cm. water, 2 had postoperative deterioration of compliance and 1 had preoperative detrusor- sphincter dyssynergia. Conclusions: Routine preoperative and postoperative urodynamic evaluations in children with the tethered cord syndrome without clinical changes to urological status may be important. The majority of clinically asymptomatic children will demonstrate preoperative urodynamic findings that improve postoperatively, which serves as another marker of progress after spinal cord untethering. Moreover, some asymptomatic children will demonstrate changes to the urinary tract that merit management changes, such as detrusor-sphincter dyssynergia, elevated bladder storage pressures and poor compliance, which may have otherwise been delayed in recognition.