Detrusor instability: a delayed complication in association with the artificial sphincter.

Of 45 children with an artificial sphincter 6 had elevated filling pressure of the detrusor and/or uninhibited contractions of the bladder after the implantation surgery, which produced hydronephrosis in 3 and urinary incontinence in 3. All affected individuals had myelodysplasia (17 per cent of this subgroup), 3 had evidence of tethering of the spinal cord and 3 may have had unrecognized detrusor hypertonicity, which was masked by the low outlet resistance before sphincter implantation. Corrective surgery consisted of either decompressive laminectomy with untethering of the spinal cord or augmentation cystoplasty when indicated. Factors affecting the change in the detrusor postoperatively, and recommendations for improved selection and surveillance of individuals undergoing implantation of the artificial device are promulgated.