Objective: To detect prospectively neurogenic damage in patients with urinary retention responding to sacral nerve stimulation (SNS) after hysterectomy for benign disease.
Patients and methods: From August 1995 to February 2002, 13 of 15 patients (mean age 43 years, sd 7) with urine retention for a mean (sd, range) of 25 (22, 6-240) months after hysterectomy for benign disease, were prospectively evaluated and treated with SNS. They were assessed using urodynamics at baseline and during the test stimulation. Sensory evoked potentials (SEPs), electrical sensory threshold (EST) measurements of the pudendal nerve, bladder neck and the bladder (2 Hz, 0-300 V), and needle electromyography of the external urethral sphincter (EUS) were undertaken in all patients.
Results: De-afferentiation (EST >/= 200 V) was limited to the bladder in four of the 13 patients and extended to the bladder neck in one other, and was matched by no response at the SEP. Relative ESTs of the bladder neck correlated inversely with residual urine (r = - 0.76, P = 0.01, x = 546, fx = 1.22) and bladder capacity (r = - 0.77, P = 0.01, x = 611, fx = 1.26) at diagnosis. Complex repetitive discharges and decelerating bursts of the EUS were seen in these five patients. Unilateral SNS was applied in 10 patients (bilateral in three). A revision was needed in six patients. Uroflowmetry at the last follow-up showed a mean (sd) maximum urinary flow rate of 22 (18) mL/s (not significantly different from during trial stimulation) with residual urine of 50-100 mL in two and 200-400 mL in three patients. Intermittent catheterization was needed in four patients.
Conclusion: Urinary retention after hysterectomy for benign disease is associated with de-afferentiation of the bladder wall in some patients and is correlated inversely with the relative EST of the bladder neck. A Fowler syndrome was detected in five patients. For residual urine, about half the patients have a good and a third a partial long-term effect; we now offer SNS as a further treatment option.