BERKELEY, CA (UroToday.com) - It is established and frequently quoted that overactive bladder (OAB) affects millions of adults worldwide, with profound social, emotional, and economic costs.
The algorithm of care for these patients, as suggested by the recently released AUA/SUFU Guideline for the diagnosis and treatment of patients with overactive bladder, begins with lifestyle and behavioral changes, followed by antimuscarinic agents.
For those patients with idiopathic OAB in whom behavioral changes, physiotherapy, and antimuscarinic therapy do not result in the desired improvement in symptoms, neuromodulation via percutaneous tibial nerve stimulation (PTNS) or sacral nerve stimulation (SNS) is included as the next step in the algorithm of care (botulinum toxin is awaiting FDA approval for this indication). Both AUA/SUFU and the NICE guidelines include PTNS as a safe and effective means of modulating bladder reflexes and improving the symptoms of OAB.
Although both PTNS and SNS are believed to modulate neural pathways, PTNS and SNS target different neural circuitry in the central nervous system, represent different levels of invasiveness, have different adverse effects, and present different cost profiles. In this review article, these issues are examined and the recommendation for prioritizing the percutaneous method is presented.
PTNS utilizes a minimally invasive approach incorporating stimulation of the posterior tibial nerve for 30 minutes, at 1-week intervals, for 12 sessions initially. Numerous case series and registries, three randomized trials, and two studies of long-term durability have clearly demonstrated that PTNS significantly reduces frequency, urgency, urgency incontinence, and nocturia. The improvement in symptoms has been demonstrated to be durable, with one study demonstrating no regression of benefits at 24 months, with an average of 1.3 sessions per month. The cost of the first year of therapy has been estimated to be $3,500, and side effects are minimal and transient. PTNS is a low cost, minimally invasive therapy that can be conducted in an office setting; this is in distinct contrast to SNS permanent implantation. SNS has been demonstrated to be effective in reducing symptoms of OAB. However, SNS first requires both a test period with temporary electrodes and an external stimulator, followed, if effective, with permanent surgical implantation of electrodes (via a sacral foramina) and a permanent generator. The cost of SNS over three years is estimated at $26,269, and the side effect profile is significant, with 33-67% of patients needing repeat surgery within 5 years.
Care of patients with OAB continues to evolve, and therapy is individualized, based on a patient’s response, comorbidities, and expectations. Many OAB patients will not experience improvement in symptoms to meet their expectations with conservative measures or pharmacotherapy. These refractory OAB patients can benefit from additional therapy such as neuromodulation. Although both PTNS and SNS therapy utilize neuromodulation, PTNS is less invasive, can be performed in an office setting, and has lower costs and lower side effects. These parameters seem to indicate that PTNS should be considered as a treatment option prior to surgical intervention. Further studies are needed to define the position of both PTNS and SNS in the algorithm of care; these studies should evaluate not only efficacy and safety, but also cost effectiveness. In addition, studies to assess whether the response or lack of response to PTNS can predict SNS response should be strongly encouraged.
David R. Staskin, MD as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.