Urodynamic predictability of voiding following incontinence surgery.

To predict the duration of postoperative bladder drainage required after incontinence surgery, 30 patients were studied preoperatively using voiding-simultaneous urethrocystometry. Based on changes in bladder, urethral, and abdominal pressures, patients were divided into three groups. Patients who demonstrated adequate bladder contraction during voiding did not need prolonged catheterization (P less than .005). Patients who did not demonstrate adequate detrusor contraction and used Valsalva maneuver during voiding were at 12 times greater risk of requiring prolonged postoperative catheterization (P less than .05). Changes observed in urethral and abdominal pressures individually during voiding were not significant predictors of the need for prolonged catheterization. Preoperative knowledge of voiding mechanisms can predict postoperative catheterization need.