Bladder and external urethral sphincter function after prenatal closure of myelomeningocele

Purpose: We compared urodynamic findings in patients who underwent prenatal closure of myelomeningocele with those of patients who underwent postnatal closure, and equivalent lower urinary tract evaluations. Materials and Methods: Urodynamic studies of 5 patients (2 boys, 3 girls) who underwent prenatal closure of myelomeningocele were compared to those of 88 patients with similar level lesions who underwent repair postnatally between 1979 and 2002. Results: All 5 patients in the prenatally treated cohort had lower lumbosacral lesions on neurological examination. These patients displayed no evidence of electromyographic activity, indicating complete denervation of the external sphincter. In comparison 34 of the 88 patients in the postnatal cohort (39%) lacked sphincter activity at newborn examination, with similar findings noted at 1-year evaluation. In terms of bladder function all 5 patients in the prenatal cohort exhibited detrusor overactivity, compared to 33 of the 88 patients (38%) in the postnatal cohort at the newborn examination, with similar findings at 1-year evaluation. Conclusions: Fetal closure of myelomeningocele is associated with a higher incidence of complete denervation of the external urethral sphincter and detrusor overactivity compared to postnatal closure. Patients who undergo this novel procedure should undergo urodynamic studies in the immediate newborn period and should be under close postnatal surveillance to document possible tethering of the spinal cord, urinary incontinence and increased detrusor pressures.