October 18, 2000
Position Statement Regarding Sacral Nerve Stimulation For Urinary Incontinence
Presented to the HCFA Medical and Surgical Procedures Panel
The American Urological Association (AUA) has based its position statement upon a literature review of evidentiary support for specific sacral nerve stimulation of the lower urinary tract dysfunction (specifically urinary urgency, frequency and urge incontinence). Primary source of documents is as follows:
The preceding materials were reviewed to determine the efficacy of the therapy as well as the adequacy of evidence supporting the utilization of this treatment (sacral nerve stimulation) and also the size (magnitude) of the help effect of these interventions.
Summary of AUA Recommendations
With respect to sacral nerve stimulation, there is sufficient evidence both from randomized, controlled trials as well as from objectively performed nonrandomized, control data, which would support the utilization of sacral nerve stimulation as an intervention for refractory motor urgency incontinence as well as urinary urgency, frequency, and urinary retention in the treatment of voiding dysfunction of the lower urinary tract.
Sacral nerve stimulation is defined herein as direct electrical stimulation of a continuous nature to the pelvic nervous arc as applied either by direct implantation into the sacral nerve foramina or by long tract stimulation of the common peroneal nerve (emerging alternate delivery pathway).
On the basis of expert opinion, the AUA would like to go on record as recommending sacral nerve stimulation as a standard therapy for patients with refractory voiding dysfunction (motor urge incontinence, urinary urgency and frequency, and urinary retention) in those patients who have failed behavioral therapies (fluid restriction, dietary modification, voiding re-training, and/or specific pelvic floor physiotherapy) and anticholinergic agents, either due to an inability to tolerate those agents, or due to persistent symptoms despite those agents. Approximately 70 percent of those refractory patients will respond to sacral nerve stimulation.
Based on our literature review, we believe that sacral nerve stimulation represents an approach providing a significant improvement in healthcare delivery (level I), and should be classified as a breakthrough technology.
This recommendation is based on HCFA's seven categories of effectiveness compared to standard therapies, including anticholinergic therapy and peripheral electrical stimulation utilized in a temporary fashion.
Based upon review of the literature, limited, multi-institutional randomized and controlled (RCT) data studies demonstrate dramatic improvement in patients with refractory urgency, frequency, and urge incontinence. Additionally, single-arm, non-randomized data also support this intervention for the individual components of urinary urgency/frequency and urge incontinence.
Bosch, et. al., summarized their experience with 45 patients treated with implantation and who were followed for a long period. Of those patients implanted for longer than 47 months, 18 (40%) were cured of incontinence and 9 (20%) had partial success, as defined by greater than 50% reduction in symptoms. Thirty-three percent of patients (19 of 44) actually had complete resolution of bladder overactivity. There was a need for device revision in 37% of these patients.
Schmidt, et. al., reported another randomized, prospective study in the treatment of motor urge incontinence (155 urge incontinent patients). The stimulation group of 34 patients was compared to a delayed treatment group of 42 (control group). At six-month follow-up, the number of daily incontinence episodes (9.7 pre to 2.6 post, 73% reduction), severity of episodes, and quality of life were all substantially improved in the modulation group as compared to the control group. Of the 34 in stimulation group, 47% (16 patients) became completely dry and an additional 29% (10 patients) demonstrated greater than 50% reduction in their incontinent episode, as well as pad utilization. Quality of life data (SF-36) was improved with respect to physical functioning and general health as compared to the delayed treatment group. Therapy evaluation testing (device deactivation followed by reactivation) revealed a return to baseline severity following deactivation, which corrected to prior improvement levels with reactivation. This efficacy was sustained at 18 months post follow-up with cohort analysis. Complications associated with this therapy included: pain at generator site (approximately 16%), implant site pain (19%), and lead migration (7%). Surgical revision was required in 32.5% of those patients, with 92% of adverse events resolving after intervention. Most of the adverse events reported were minor in nature.
In the study by Hassouna, et. al., which was a randomized, controlled study (with 222 patients included) utilizing six-month voiding diary results, there was significant improvement after sacral nerve stimulation in the treated (stimulation) group with respect to frequency resolution (16.92 events decreased to 9.3), volume per void (118 cc/void to 226 cc/void), and degree of urgency reduction (reduction of overall 2.2 score to 1.6). The patients in the control group showed no significant changes in voiding parameters at six-month follow-up as compared to the stimulation group. Substantial improvements in quality of life were also noted on SF36 (evaluation of patient's quality of life) data. This treatment effect was further demonstrated at the six-month time-point after implant. The neurostimulator in the stimulation group was deactivated at that time and the treated patients returned to their baseline symptomatology. The recurrent symptomatology resolved with reactivation of the stimulator, which was documented again at 12 and 24 months. Chronic follow-up at 24 months (Siegel, et. al.), showed a persistence of treatment effect with 56% of patients demonstrating at least a 50% reduction in urinary frequency.
The evidence included, although limited somewhat by the number of RCTs, does demonstrate substantial magnitude of treatment effect. This efficacy is also durable and unlikely to be altered by any placebo effect.
Although certain risks are involved with this intervention (about 50% of patients with the permanent implant experienced one or more adverse events), no serious complications were noted and the majority of the adverse events were resolved with appropriate management. It would appear that the benefit of this intervention is greater than any inherent risk.
The magnitude of treatment effect is significant with this intervention and is more significant than the most common previous intervention for this population, surgical augmentation of the bladder, with an overall success rate of 38% (continence with spontaneous voiding).
These studies represent a summary of a sequence of studies, as noted in the enclosed bibliography, which again demonstrates the efficacy of sacral nerve stimulation over standard therapies and the breakthrough nature of this intervention. The majority of the other studies are single-arm studies and may have some over-estimation of treatment effect; however, the results are remarkably similar to those of the RCT data.
It is the conclusion of the AUA that this intervention represents a technology very similar to the cardiac pacemaking technologies of the 1960's, where further evolution will be necessary. This evolution will mainly focus on decreasing the revision rate and improving overall patient treatment successes from the already high rates.
Based upon this treatment of refractory patients, it is recommended that this therapy be considered as a breakthrough type therapy, which will undergo continued and further refinement in the next few years.