Postpubertal urodynamic and upper urinary tract changes in children with conservatively treated myelomeningocele

Purpose: We examined the urodynamic and upper urinary tract changes in children with myelomeningocele treated conservatively through puberty at our institution between 1980 and 2006. Materials and Methods: A total of 40 patients were exclusively treated conservatively with or without anticholinergics and/or clean intermittent catheterization through puberty at our institution. The records of 37 patients (17 males and 20 females) were available for review and constituted the subject matter for our study. The neurological lesion was sacral in 4 patients, lumbosacral in 5, thoracic in 12 and lumbar in 16. Clinical evaluations, radiological imaging studies of the upper urinary tract and urodynamic studies were repeated every 6 to 12 months. Data were collected and comparisons were made with respect to prepubertal (age 10 years) and postpubertal (15) continence status, urodynamic parameters and upper urinary tract changes. Children spontaneously achieving urinary continence postpubertally were examined in a similar fashion as a separate subgroup. Continence was defined as a dry interval of 4 hours or more. Results: Of the 26 patients with urinary incontinence before puberty 12 (2 males and 10 females, 45%, p < 0.003) achieved continence following puberty. Hydronephrosis remained stable in 4 patients, improved in 3 and was new onset in 3 (p > 0.05). Vesicoureteral reflux persisted in 1 patient, resolved in 4 and was new onset in 1 (p > 0.05). Total cystometric bladder capacity, maximum detrusor pressure and detrusor leak point pressure all increased significantly after puberty, from 277 +/- 82 to 487 140 ml, 45 +/- 17 to 54 +/- 20 cm H,O and 49 +/- 16 to 59 +/- 21 cm H2O, respectively. In patients achieving urinary continence following puberty total cystometric bladder capacity increased significantly from 284 58 to 473 +/- 93 ml (p < 0.005). Maximum detrusor pressure and detrusor leak point pressure showed insignificant changes after puberty, increasing from 45 11 to 47 +/- 16 cm H2O and from 46 +/- 11 to 55 21 cm H2O, respectively. Conclusions: This study demonstrates that total cystometric bladder capacity, maximum detrusor pressure and detrusor leak point pressure increase significantly in patients with myelomeningocele following puberty. The increase in bladder capacity could be attributed to increasing bladder outlet resistance resulting from prostate gland enlargement in males and estrogenization in females. A significant number of patients spontaneously achieve continence at puberty, and continence becomes more likely when increased total cystometric bladder capacity is not associated with an increase in maximum detrusor pressure. Finally, no significant postpubertal upper urinary tract deterioration was observed in our series.