Hypothesis / aims of study
Sacral Neuromodulation (SNM) has been found effective for the treatment of ”dry and wet” overactive bladder (OAB), Bladder Pain Syndrome/interstitial cystitis (BPS/IC) and voiding dysfunction (VD). Our department was one of the first two in Canada that started SNM treatment in 1994. Several studies show the safety and efficacy of SNM at short- and medium- term follow-up . In this study, we review the long-term outcomes and complications of SNM treatment for any indication.
Study design, materials and methods
This was a retrospective study of all patients who underwent test phase (peripheral nerve evaluation- PNE and/or 1st stage procedure) and then SNM by a single surgeon from 1994 – 2017. The primary outcome was to assess long-term outcomes of SNM using the global response assessment scale. This included percent improvement in pain, as well as storage lower urinary tract symptoms (urinary frequency, urgency, urge incontinence, and nocturia), and voiding lower urinary tract symptoms (weak stream, hesitancy, intermittency, straining and bladder emptying). Secondary outcomes included number of revisions, reason for revision, complications and rate of device removal.
Total of 434 patients were included with 373 (86%) female and 61 (14%) male patients. All patients underwent Test Phase and 241/435 (55%) patients eventually received a SNM implant. Mean age at time of implant was 49 years. Of the patients that received SNM implant, 118 (49%) had a diagnosis of BPS/IC, 24/241 (10%) with VD, 86/241 (36%) with OAB, and 13/241 (5%) with neurogenic lower urinary tract dysfunction (NLUTD). Mean follow-up time was 5.8 years (1 month–20.5 years). 76/241 (32%) devices were removed due to device failure or complication. 167/241 (69%) patients underwent at least one follow-up surgical revision [Figure 1]. The mean percentage improvement in symptoms on the last follow-up (mean 6.4 years) for patients with successful SNM was 69%. At the end of data collection, 166/241 (69%) devices remained in-situ with ongoing follow-up [Figure 2].
Interpretation of results
This retrospective study provides valuable insight due to the long-term follow-up. Moreover, we now have a better understanding of the common complications and rate of these complications that patients experience in the long run. Lastly, a mean improvement of 69% in symptoms highlights the serious consideration that SNM needs to be given by Urologists when looking for options for patients with a variety of different urologic concerns.
Traditionally patients with OAB, VD and IC, who failed conservative measures were left only with highly invasive options, such as augmentation cystoplasty and urinary diversions. In this chart review, we find that SNM is an effective option prior to major surgical interventions. There is a high revision rate but overall, SNM is a minimally invasive procedure with a good safety profile and excellent long-term outcomes.