Surgery Section - Posterior Tibial Nerve Stimulation for Voiding Dysfunction

IMPORTANT REMINDER

Regence Medical Policies are developed to provide guidance for members and providers regarding coverage in accordance with contract terms. Benefit determinations are based in all cases on the applicable contract language. To the extent there may be any conflict between the Medical Policy and contract language, the contract language takes precedence.

PLEASE NOTE: Contracts exclude from coverage, among other things, services or procedures that are considered investigational or cosmetic. Providers may bill members for services or procedures that are considered investigational or cosmetic. Providers are encouraged to inform members before rendering such services that the members are likely to be financially responsible for the cost of these services.

Description

Posterior tibial nerve stimulation (PTNS) is a technique of electrical neuromodulation for the treatment of voiding dysfunction in patients who have failed behavioral and/or pharmacologic therapies. The tibial nerve is accessed using a fine-needle electrode inserted slightly above the ankle, and low-voltage electrical stimulation is delivered. The course of treatment is typically 10–12 weeks of 30-minute weekly sessions. The posterior tibial nerve is located near the ankle; it is derived from the lumbar-sacral nerves (L4-S3), which control the bladder detrusor and perineal floor. Altering the function of the posterior tibial nerve with posterior tibial nerve stimulation is believed to improve voiding function and control. 

Voiding dysfunction includes urinary frequency, urgency, incontinence, and nonobstructive retention. Common causes of voiding dysfunction are pelvic floor dysfunction (from pregnancy, childbirth, surgery, etc.), inflammation, medication (e.g., diuretics and anticholinergics), obesity, psychogenic factors and disease (e.g., multiple sclerosis, spinal cord injury, detrusor hyperreflexia, diabetes with peripheral nerve involvement).  In addition, PTNS has been has been proposed for the treatment of urgency and frequency caused by interstitial cystitis.

The procedure for PTNS consists of the insertion of a needle above the medial malleolus into the posterior tibial nerve followed by the application of low voltage (10mA, 1-10 Hz frequency) electrical stimulation which produces sensory and motor responses (i.e., a tickling sensation and plantar flexion or fanning of all toes). Noninvasive PTNS has also been delivered with surface electrodes. PTNS studies have been designed as 30-minute sessions given weekly for 10-12 weeks. Recently, consideration has been given to increasing the frequency of treatments to 3 times per week to speed achievement of desired outcomes. However, an optimal treatment approach has not been identified and the durability of PTNS is uncertain.

PTNS must be distinguished from acupuncture with electrical stimulation.  In electrical acupuncture, needles are also inserted just below the skin, but the placement of needles is based on specific theories regarding energy flow throughout the human body. Thus in PTNS, the location of stimulation is directly in the posterior tibial nerve rather than using the theories of energy flow that guide placement of stimulation for acupuncture.

In July 2005, the Urgent® PC Neuromodulation System (Uroplasty, Inc.) received 510(k) marketing clearance for percutaneous tibial nerve stimulation to treat patients suffering from urinary urgency, urinary frequency, and urge incontinence. This device was cleared as a class II ‘‘nonimplanted, peripheral nerve stimulator for pelvic floor dysfunction” because it was considered to be substantially equivalent to the previously cleared percutaneous Stoller afferent nerve system (PerQ SANS System) in 2001 (K992069, UroSurge, Inc.).

PTNS was developed as a less-invasive treatment alternative to traditional sacral root neuromodulation which has been successfully used in the treatment of urinary dysfunction, but requires implantation of a permanent device. In sacral root neuromodulation, an implantable pulse generator that delivers controlled electrical impulses is attached to wire leads that connect to the sacral nerves, most commonly the S3 nerve root that modulates the neural pathways controlling bladder function.  Note: Stimulation of the sacral nerve as a treatment of incontinence is discussed separately in policy No. Surgery 134. Pelvic floor stimulation as a treatment of urinary incontinence refers to electrical stimulation of the pudendal nerve and is addressed separately in Regence Allied Health policy No. 4.

Policy/Criteria

Posterior tibial nerve stimulation for urinary dysfunction, including but not limited to urinary frequency, urgency, incontinence and retention, is considered investigational.

Scientific Background ^[1]

Study selection criteria for the evaluation of evidence on posterior tibial nerve stimulation (PTNS) included the following:

• The study contained original empirical data
  
  
• The study design included a treatment group and a control group
  
  
• The study reported on a health outcome relevant to the condition treated
  
  
• The study used a random assignment, control group design

Several clinical studies have reported on the use of PTNS with some favorable outcomes, including reductions in urinary frequency and urgency. However, no randomized, controlled trials have been published comparing PTNS to placebo or other voiding dysfunction treatments. In a prospective observational study, Nuhoglu and colleagues treated 35 patients with overactive bladder with 10 weekly 30-minute sessions using the UroSurge device. ^[2] Nineteen patients (54%) experienced significant reductions in urinary urgency and increases in urine volume after therapy. However, these effects were maintained in only 8 patients (23%) after one year. In a small study of 11 patients, van der Pal and colleagues also found limited durability of PTNS treatment effects as increases in incontinence and/or voiding frequency occurred in 50% or more patients 6 weeks after treatment. ^[3] When treatment was resumed, the incontinence and/ or voiding frequency decreased 50% or more. While these studies are small, the effects of PTNS appear to be short term. And as the van der Pal authors indicate, continuous PTNS may be necessary. Finally, Finazzi and colleagues found no differences in outcomes in 35 patients randomized to PTNS weekly versus 3 times per week. ^[4] The authors noted patients in both treatment groups had subjective improvements after six to eight sessions of PTNS suggesting more frequent treatment initially may result in earlier achievement of desired effects even though the frequency of PTNS did not influence the final outcomes in this study.

Van der Pal and colleagues published an analysis of quality of life questionnaires from 29 patients who were treated with PTNS (3 times per week for 4 weeks) for urge urinary incontinence. ^[5] Information from Figure 1 of the article indicates that at least 12 of the subjects had either no change or an increase in the number of pads used. The authors report that they are currently conducting a randomized double-blind placebo-controlled trial. Another study assessed the efficacy of 12 weeks (1 time per week) of PTNS in 15 patients with chronic pelvic pain in an open prospective clinical trial. ^[6] The study found subjective improvements in VAS pain scores (8.1 to 4.1) and VAS urgency (4.5 to 2.7), with no change in the number of voids or bladder volume. Since these subjective improvements may be due to placebo, double-blinded controlled trials are needed. In addition, since questions remain about the long-term efficacy of PTNS, longer follow-up will be needed to evaluate this procedure.

Peters and colleagues published a randomized controlled blinded pilot study to validate and assess the feasibility of a sham device for PTNS. ^[7] Ten of the 30 healthy volunteers (33%) correctly identified the sham procedure. This percentage is below the 50% that could be expected by chance, so the authors concluded that the procedure was a feasible sham.  Another randomized trial, also by Peters and colleagues, was supported by Uroplasty, Inc. and was a non-blinded comparison of PTNS and extended-release tolterodine (Detrol LA) for treatment of overactive bladder syndrome. ^[8] The study included 100 patients, over 90% women, with at least eight voids per 24 hours (mean 12.3). The primary outcome was the non-inferiority of PTNS in the mean reduction in the number of voids per 24 hours after 12 weeks of treatment. Study findings showed non-inferiority of PTNS; however, these findings were based on results for only 84 patients. The decrease in voids per day was 2.4 in the PTNS group and 2.5 in the tolterodine group. The study reported mixed findings for a number of secondary outcomes, some of which were based on patient reports. However, these results are unreliable because they could have been affected by the patient reports having been obtained in person for the PTNS group as part of their weekly session but obtained over the phone for the medication group. There were no statistically significant differences in the PTNS and tolterodine groups for other symptoms recorded in the voiding diary. This finding includes episodes of nocturia (-0.7 and -0.6, respectively) and episodes of moderate to severe urgency per day (-2.2 and -2.9, respectively). There was a statistically significant difference in the proportion of patients reporting improvement or cure in symptoms (79.5 vs. 54.8%). Limitations of this study include the lack of a sham/placebo group both to mitigate the potential bias due to subjective outcomes and to evaluate whether either treatment is better than placebo. In addition, the results for 16% of the original 100 patients is not reported, data were not reported for compliance with medication therapy, and the study includes short-term efficacy only.

In conclusion, randomized trials with appropriate control groups are needed to determine the durability and short and long-term effects of PTNS on voiding dysfunction. Evidence from clinical series tends to overestimate treatment effect. These studies do not account for placebo effects or for dropouts by using intent-to-treat analysis. Randomized, controlled, blinded clinical trials are needed to control for the effects of bias and to demonstrate the efficacy of PTNS. Additionally, further randomized trials are needed to determine appropriate treatment periodicity. Clinicaltrials.gov indicates that the OrBIT trial, using PTNS for the overactive bladder, should be completed September, 2008. ^[9] Results from this trial are not yet published.

References

1. TEC Assessment 1996. "Transcutaneous or Percutaneous Electrical Stimulation in the Treatmetn of Chronic and Postoperative Pain." BlueCross BlueShield Association Technology Evaluation Center, Vol. 11 Tab. 21.
2. Nuhoglu B, Fidan V, Ayyildiz A, Ersoy E, Germiyanoglu C. Stoller afferent nerve stimulation in woman with therapy resistant over active bladder; a 1-year follow up. Int Urogynecol J Pelvic Floor Dysfunct. 2006 May;17(3):204-7.  PMID: 16049624
3. van der Pal F, van Balken MR, Heesakkers JP, Debruyne FM, Bemelmans BL. Percutaneous tibial nerve stimulation in the treatment of refractory overactive bladder syndrome: is maintenance treatment necessary? BJU Int. 2006 Mar;97(3):547-50.  PMID: 16469023
4. Finazzi Agro E, Campagna A, Sciobica F, et al. Posterior tibial nerve stimulation: is the once-a-week protocol the best option? Minerva Urol Nefrol. 2005 Jun;57(2):119-23.  PMID: 15951736
5. van der Pal F, van Balken MR, Heesakkers JP, Debruyne FM, Kiemeney LA, Bemelmans BL. Correlation between quality of life and voiding variables in patients treated with percutaneous tibial nerve stimulation. BJU Int. 2006 Jan;97(1):113-6.  PMID: 16336339
6. Kim SW, Paick JS, Ku JH. Percutaneous posterior tibial nerve stimulation in patients with chronic pelvic pain: a preliminary study. Urol Int. 2007;78(1):58-62.  PMID: 17192734
7. Peters K, Carrico D, Burks F. Validation of a sham for percutaneous tibial nerve stimulation (PTNS). Neurourol Urodyn. 2009;28(1):58-61.  PMID: 18671297
8. Peters KM, Macdiarmid SA, Wooldridge LS, et al. Randomized trial of percutaneous tibial nerve stimulation versus extended-release tolterodine: results from the overactive bladder innovative therapy trial. J Urol. 2009 Sep;182(3):1055-61.  PMID: 19616802
9. cited 3/15/10]; Available from: http://www.clinicaltrials.gov/ct2/search

Cross References

Pelvic Floor Stimulation as a Treatment of Urinary Incontinence, Regence Medical Policy Manual, Allied Health, Policy No. 4

Biofeedback, Regence Medical Policy Manual, Allied Health, Policy No. 32

Sacral Nerve Modulation/Stimulation for Pelvic Floor Dysfunction, Regence Medical Policy Manual, Surgery, Policy No. 134

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