Andrew Sokol, MD
Georgetown University School of Medicine
Al-zahrani AA, Elzayat EA, Gajewski JB. Long-term outcome and surgical interventions after sacral neuromodulation implant for lower urinary tract symptoms: 14-year experience at 1 center. J Urol. 2011;185:981-986.
Sacral neuromodulation (SNM) is an FDA-approved treatment for refractory urgency incontinence, urinary frequency/urgency syndrome, and non-obstructive idiopathic urinary retention. Several studies show its efficacy at short and medium-term follow-up. This study retrospectively assesses the long-term outcomes, incidence, and causes of surgical re-intervention after SNM implantation for lower urinary tract dysfunction.
This retrospective study included 96 SNM device implants in 88 women and 8 men from 1994–2008 at a single institution.
- Records of all patients receiving permanent SNM implant at single institution were reviewed
- Patient demographics, indications for SNM, history and physical examination parameters, voiding diary values, urodynamic data, and cystoscopic findings were abstracted
- SNM was implanted after conservative and pharmacological treatment failed and if 50% or greater improvement was seen after percutaneous nerve evaluation test (PNE)
- Indications for implant included urgency incontinence (UUI), bladder pain syndrome (BPS) (with symptoms of frequency 100%, urgency 96%, and nocturia 94%), and idiopathic urinary retention (IUR)
- Clinical success criteria were based on a 5-level global response assessment (GRA) scale assessed by direct patient interview
- Long-term success was documented in those with moderate symptom improvement or above (“good outcome” as assessed by the GRA)
- A ≥ 50% reduction in the number of catheterizations was considered success in those with idiopathic urinary retention
- All adverse events, complications and surgical interventions were recorded
- Standard statistics were used to compare groups for success rates, complications, and surgical intervention after implant
196 patients underwent PNE, and 49% of these underwent permanent SNM implant. PNE success rates by indication did not differ statistically (43.9% for IUR, 54.4% for UUI, 66% for BPS).
- Those with BPS and IUR were younger than those with UUI
- Median follow-up was 50.7 months, with all patients completing at least 1 year of follow up
- Long-term success was 87.5% in IUR, 84.8% in UUI, and 72% in BPS (P = 0.6)
- The overall explant rate was 20.8% (highest and briefest time to explant in BPS group and lowest in IUR group)
- Indications for explant were poor result (12.5%), painful stimulation (6.25%), and radiation of stimulation to the leg (2%)
- The explantation risk increased with the revision rate (13.2% in those with no revision to 30.2% in those with revision, P = 0.04)
- The overall revision rate was 39% and was highest in the IUR group (56%)
- The most common reasons for revision were poor response (58.5%), local pain from the implanted pulse generator (17%), and painful stimulation or radiation to the leg (12%)
- Median time to revision was 26.5 months (with shortest times to revision for pain)
- The revision rate decreased from 50% to 31% with the introduction of the tined lead (P = 0.1)
- Mean battery life was 101.8 months (90.8, 113, and 124 months with BPS, UUI, and IUR [P = 0.22])
This paper is helpful in counseling patients about long-term outcomes with SNM. More specifically, it is helpful when counseling patients about the risks of revision and explanation and the most common reasons for both of these outcomes. The 39% risk of surgical re-intervention is consistent with long-term results in worldwide clinical trials.1,2
The generalizability of this study may be limited in that all surgeries were performed in a single center with a high degree of experience with SNM. Additionally, painful bladder syndrome was the reason for implant in 47.9% of patients in this study, and this is not an FDA approved indication for SNM in the United States.
However, this study does report the longest follow-up for SNM available in the literature, and supports its long-term success in patients with idiopathic urinary retention, urgency incontinence, and bladder pain syndrome. This paper reinforces the place of SNM in the armamentarium of physicians treating patients with lower urinary tract symptoms.
- Siegel SW, Catanzaro F, Dijkema HE, et al. Long-term results of a multicenter study on sacral nerve stimulation for treatment of urinary urge incontinence, urgency-frequency, and retention. 2000;56:87-91.
- van Kerrebroeck PE, van Voskuilen AC, Heesakkers JP, et al. Results of sacral neuromodulation therapy for urinary voiding dysfunction: outcomes of a prospective, worldwide clinical study. J Urol. 2007;178:2029-34.