Objectives: To assess the long-term functional outcomes of sacral neuromodulation (SNM) in the treatment of refractory idiopathic overactive bladder (IOAB) and to determine predictive factors for success.

Materials and Methods: To obtain long-term data, all consecutive patients suffering from IOAB and treated by SNM at a single tertiary care center between December 1996 and December 2004 were included. Data regarding patient demographics, past medical, and surgical history, bladder diary, complications as well as device revision and removal rates were collected. Success was defined as an improvement > 50% of any clinical parameter.

Results: Overall, 34 patients, with a median age of 57.8 years (IQR 44.8–65.7) were included. Immediately after definitive implanta- tion, 2 (6%) patients were lost to follow-up. After a median follow-up of 9.7 years (IQR 4.7–12.0), SNM was considered successful in 20 (63%) patients. Mean amount of protections used per 24 hours significantly decreased (4.1 preoperatively vs. 1.8 at the last follow-up visit, p = 0.02). Devices were removed in 2 (6%) patients due to pain and lack of efficacy. Twenty-two revision surgeries were performed in 15 (47%) patients. First revision surgery occurred after a mean of 6.2 years (+/- 3.1). Revision surgeries were mainly performed for end of battery life/device dysfunction (n = 18,82%). No significant predictor for success was identified. Revision-free survival curve for patients implanted with a SNM device is reported on figure 1.

The main limitation of this current study may be the small sample size. It is challenging to have a similar long-term follow-up in a larger population. Indeed, European SNM nation-wide registries managed to include more patients, but their follow-ups were shorter (< 5 years) (1). A Canadian group published its 14-year SNM experience (median follow-up of 50.7 months), however the patient cohort was heterogeneous, as it included patients with bladder pain syn- drome, Urge Urinary Incontinence, and idiopathic urinary retention (2).

With a median follow-up time of 9.7 years, our study showed that SNM has a moderate efficacy of 63% (> 50% improvement) as a treatment for refractory IOAB. Moreover, it is a well-tolerated therapy with a relatively low complication rate. We were unable to identify factors predicting for SNM success. SNM is a good treatment option for refractory IOAB as it is minimally invasive and has a respectable long-term outcome. Patients may be informed accordingly.

Kessler TM, Buchser E, Meyer S et al. Sacral neuromodulation for refractory lower uri- nary tract dysfunction: results of a nationwide registry in Switzerland. Eur Urol 2007; 51:1357–1363. DOI:10.1016/j.eururo.2006.11.011.
Al-zahrani AA, Elzayat EA, Gajewski JB. Long-term outcome and surgical interven- tions after sacral neuromodulation implant for lower urinary tract symptoms: 14- year experience at 1 center. J Urol 2011;185:981–986. DOI:10.1016/ j.juro.2010.10.054.