Sacral neuromodulation treating chronic pelvic pain: a meta-analysis and systematic review of the literature

Introduction and hypothesis Sacral neuromodulation (SNM) is gaining popularity as a treatment option for chronic pelvic pain (CPP). Our hypothesis is that SNM is effective in improving CPP. Methods A systematic search was conducted through September 2018. Peer-reviewed studies using pre- and postpain intensity scores were selected. The primary outcome was pain improvement on a 10-point visual analog scale (VAS) (adjusted or de novo) in patients with CPP. Secondary outcomes included comparing SNM approaches and etiologies and evaluating lower urinary tract symptoms (LUTS). Results Fourteen of 2175 studies, evaluating 210 patients, were eligible for further analysis. The overall VAS pain score improvement was significant [weighted mean difference (WMD) −4.34, 95% confidence interval (CI) = −5.22, to−3.64, p < 0.0001)]. Regarding SNM approach, both standard and caudal approaches had significant reduction in pain scores: WMD −4.32, CI 95% = −5.32, to −3.31 ( p < 0.001) for the standard approach, compared with WMD −4.63, 95% CI = −6.57 to −2.69 ( P < 0.001), for the caudal approach ( p = 0.75). While significant improvement in pain was observed both in patients with and without interstitial cystitis/bladder pain syndrome (IC/BPS), the observed improvement was lower in patients with (WMD −4.13, CI 95% −5.36 to −2.90 versus without (WMD −5.72, CI 95% = −6.18, to−5.27) IC/BPS ( p = 0.02). SNM was effective in treating voiding symptoms (frequency, urgency, nocturia) associated with IC/BPS (all p < 0.01). Conclusions SNM is an effective therapy for CPP in both IC/BSP and non-IC/BSP patients, with better results in non-IC/BSP patients. Outcomes of the antegrade caudal approach were comparable with the standard retrograde approach.