Sacral nerve stimulation for voiding dysfunction: One institution's 11-year experience.
AIM: The purpose of this study was to review our institution's 11-year experience with SNS for the treatment of refractory voiding dysfunction. Dating back to 1993, it covers a span of time which describes the evolution of SNS as it includes PNE trials, non-tined (bone-anchored or fascial-anchored) leads, percutaneous tined leads with two-staged procedures, and even percutaneous pudendal trials. METHODS: A retrospective review was performed on SNS patients who received an implantable pulse generator (IPG) in our practice from 12/1993 to 12/2004. After Institutional Review Board approval, consents for chart review were obtained from 104 patients, representing 44% of this neuromodulatory patient population. RESULTS: Of our population, 87% were female and 13% were male. Average age at implant was 50 years +/- 13.4 years. Duration of symptoms before implantation was 116 months (range 9-600 months). Eighty percent were implanted for a predominant complaint of urinary urgency and frequency (U/F). Overall, 22% had U/F only, 38% had concomitant urge incontinence (UI), and 20% had concomitant mixed incontinence (MI). Twenty percent were treated for non-obstructive urinary retention (UR), with half of these associated with a neurogenic etiology. Additionally, 46.2% had pelvic pain, 58.6% had bowel complaints, and 51% reported sexual dysfunction. In patients with U/F, mean voiding parameters as described by pre-implant voiding diaries revealed the following: 12.4 (+/-5.1) voids per 24 hr; 2.3 (+/-1.8) voids per night; 5.0 (+/-4.7) leaks per 24 hr; and 2.3 (+/-2.6) pads per 24 hr. Statistically significant improvements post-implantation were noted with mean decreases in the following: 4.3 voids per 24 hr; 1.0 void per night; 4.4 leaks per 24 hr; and 2.3 pads per 24 hr (all P < 0.05). In the UR group a statistically significant improvement post-implantation was noted only in voids per night, with a mean decrease of 0.8 (P < 0.05). With a mean follow up of 22 months (range 3-162 months), sustained subjective improvement was >50%, >80%, and >90% in 69%, 50%, and 35% of patients, respectively. By quality of life survey, 60.5% of patients were satisfied and 16.1% were dissatisfied with current urinary symptoms. Only 13% (14 patients) abandoned therapy, making up a significant portion of those dissatisfied with current urinary symptoms. Good overall lead durability was seen (mean 22 months, range 1-121 months), with the first successful lead proving to be the most durable (mean 28 months, range 1.4-120 months). Lead durability decreased progressively with subsequent trials. Overall, 53% of patients experienced at least one reportable event (RE) attributable to either lead or IPG. A total of 126 REs were noted, with 97% mild-to-moderate in severity. REs included lack of efficacy, loss of efficacy, infection, hematoma/seroma, migration, pain, undesirable change in sensation, and device malfunction. In this population, 47.1% of leads were tined while 52.9% were non-tined. Tined leads had an overall lower RE rate as compared to non-tined leads: 28% and 73%, respectively. CONCLUSIONS: SNS is an effective method for treating certain types of voiding dysfunction. Although 53% of patients experienced at least one RE, 97% were mild-to-moderate and did not appear to affect the continued use of this therapy. With improved technology, such as percutaneous tined leads, the RE rate is decreasing. Further analyses of subsets of this population are currently underway.