Satisfaction and quality of life after SNM have also been studied. Quality of life improvements have been reported in patients with detrusor overactivity, and a strong correlation was identified between the number of incontinence episodes and quality of life index.

Cappellano et al. [34] showed a significant improvement in the quality of life score in patients with urgency urinary incontinence who underwent SNM: at 18 months of follow-up, 90 % of subjects gave a positive response to treatment and 100 % of patients recommended it to a relative or friend. In addition, Foster et al. [35] showed that the majority of patients (84 %) were satisfied with SNM treatment.

Adverse events associated with SNM implant have been extensively discussed in the literature. A recent study reported an explantation rate of 21 % and a surgical revision rate of 39 % [36]. The most common complications [25, 28, 31] are pain at the implant site (3–42 %), lead migration (1–21 %), wound problems (5–8 %), bowel dysfunction (4–7 %), infection (4–10 %), and pulse generator problems (5 %). The majority of adverse events do not require surgical intervention, but conservative treatment. The introduction of the tined lead and the two-staged procedure have positively affected the adverse event and reoperation rates. Lower incidences of pain (2.5 %), lead migration (0.6 %), and infection (2.5 %) were reported in a follow-up study [37]. Surgical revision was required in 16 % of patients including those with reduced efficacy (10 %) [37]. The learning curve and patient selection may have an additional beneficial effect on the reoperation rates [31].

Studies comparing the effectiveness of the SNM versus BTX have produced conflicting results [15, 31]. A decision analysis model was constructed using values for efficacy and complications from the literature and the personal series. Markov state transition modeling was used with health states and transitions between states designed to fully account for the complex interplay of therapeutic efficacy and multiple possible complications. Overall outcomes and complications for the two operations (SNM vs. BTX injection) were yearly compared (Fig. 11.1), and the probability of success of the SNM was higher than the BTX injection (59 % vs. 48 %, p < 0.05, respectively).

Few studies have examined the cost-effectiveness of SNM. Siddiqui et al. [38] suggested that SNM treatment strategy was more expensive ($ 15743 vs. $ 4392) but also more effective (1.73 vs. 1.63 quality-adjusted life years – QALYs) than BTX injections in the first 2 years of therapy. However Leong et al. [39] showed that SNM treatment was cost-effective after 5 years compared to BTX injection.