Does sacral neuromodulation lead to relevant reduction in the need for intermittent catheterization? A single-center...

Sacral neuromodulation (SNM) is an approved method for second-line treatment of different therapy refractory disorders of the urinary bladder. Alongside success in overactive bladder symptoms for detrusor overactivity, SNM also was shown to succeed in chronic urinary retention (UR) of various etiology.

From October 2007 to December 2010, a cohort of 20 patients received two-stage InterStim tined-lead® (Medtronic Inc., Minneapolis, MN, USA) SNM therapy for UR. The number of electrodes implanted was decided by surgeons on the basis of patients' clinical presentation and extent of UR. Dependent on the treatment success, patients received either implantation of the implantable pulse generator (IPG) or the electrodes were removed. Median follow-up time was 12 months (1-38 months).

All 20 patients, of whom 80% were female, suffered from idiopathic or neurogenic UR for a median 60 months (7-440 months) before SNM. Median patient age was 51 years (34-68 years). Eighteen (90%) of the stimulated patients showed significant success with implantation of IPG within a median of 43 days (15-93). In the follow-up period, postvoid residual (PVR) urine of the permanent stimulated patients was reduced from a median of 350 mL to 135 mL. While this just did not reach statistical significance (p= 0.057), the median number of intermittent catheterizations (ICs) could be reduced relevantly from four to one per day (p= 0.021). The subgroup analysis of idiopathic and neurogenic UR showed relevant improvement of the vital parameters, but the number of patients was obviously too small to yield statistically significant results. Subgroup analysis according to the number of electrodes implanted revealed statistically significant reduction of IC only after unilateral SNM. PVR of ≤400 mL was a statistically significant predictor for success of SNM treatment. In the presented treatment period, only one mild adverse event occurred that could be handled conservatively.

SNM can be a successful and secure second-line therapy option for patients with chronic UR. Data suggest a more success-promising situation for idiopathic cause of disease, but the number of patients was too small to reach statistical significance. Further prospective, randomized multicenter data concerning indications and number of electrodes are necessary and highly appreciated.