4 Efficacy
This section describes efficacy outcomes from the published literature that the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the interventional procedure overview.
4.1
A systematic review of 14 articles reported post‑void residual volume from 7 of the articles (n=478). The mean difference in post‑void residual volume decreased by 236 ml (95% confidence interval [CI] 219 to 253, p<0.0001, I2=83%) after sacral nerve stimulation. A randomised controlled trial of 51 patients treated by sacral nerve stimulation or standard medical treatment, which was also included in the systematic review, reported that the mean catheter volume per catheterisation decreased from 339 ml to 49 ml at 6‑month follow‑up in the treatment group and from 350 ml to 319 ml in the control group (p<0.0001 comparing the mean differences).
4.2
The systematic review of 14 articles reported voided volume from 7 of the articles (n=478). The mean voided volume increased by 344 ml (95% CI 322 to 365, p<0.0001, I2=97%) after sacral nerve stimulation. The randomised controlled trial of 51 patients reported that the mean total voided volume per day increased from 722 ml to 1808 ml at 6‑month follow‑up in the treatment group and decreased from 560 ml to 488 ml in the control group (p<0.0001 comparing the mean differences).
4.3
The randomised controlled trial of 51 patients reported that the mean number of catheterisations per day decreased from 5.7 to 1.4 at 6‑month follow‑up in the treatment group and from 4.0 to 3.9 in the control group (p<0.0001 comparing the mean differences). At 18‑month follow‑up 58% (14 of 24) of patients treated by sacral nerve stimulation did not need catheterisation. A case series of 60 patients reported that 72% (43 of 60) of patients were voiding spontaneously and 50% (30 of 60) of patients no longer needed to use catheterisation after a mean follow‑up of 4 years. A case series of 40 patients reported that the mean number of catheterisations per day decreased from 4.3 to 1.0 after a mean follow‑up of 41 months (p<0.001) and 55% (11 of 20) of patients with complete retention were able to stop catheterisation completely.
4.4
The case series of 40 patients reported that 69% (20 of 29) of patients with complete retention and 73% (8 of 11) of patients with incomplete retention had a successful response to sacral nerve stimulation (defined by a reduction in the number of daily catheterisations by 50% and a decrease in the mean post‑void residual urine volume by 50%). A case series of 93 patients with idiopathic urinary retention reported a success rate of 73%; the cure rate (100% success) was 63% for patients with Fowler's syndrome and 54% for patients with non‑Fowler's idiopathic urinary retention.
4.5
The specialist advisers listed key efficacy outcomes as ability to void spontaneously, lower residual volume, reduced need for intermittent catheterisation, a 50% reduction in catheter volume per catheterisation, patient perception of cure or improvement, perception of improved flow rate, frequency of micturition or nocturia, pain relief, urodynamic measurements, pad tests or number of leaks per day (if overflow incontinence is present), quality of life, general health status, psychosocial measures, impact of self‑catheterisation or incontinence.