MP 7.01.29

Percutaneous Electrical Nerve Stimulation (PENS) or Percutaneous Neuromodulation Therapy (PNT)

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Medical Policy
Section Surgery	Original Policy Date 11/30/96	Last Review Status/Date Reviewed with literature search/1:2009
Issue 1:2009		Return to Medical Policy Index

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Disclaimer

Our medical policies are designed for informational purposes only and are not an authorization, or an explanation of benefits, or a contract.  Receipt of benefits is subject to satisfaction of all terms and conditions of the coverage.  Medical technology is constantly changing, and we reserve the right to review and update our policies periodically.

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Description

Policy

Policy Guidelines

Benefit Application

Rationale

This policy was originally based on a 1996 TEC Assessment of PENS for the treatment of chronic pain. (1) The objective of the 1996 Assessment was to determine if the effects of PENS exceed placebo effects. No clinical studies of PENS were identified by the 1996 Assessment, thus no conclusions about effectiveness could be reached. Subsequently, the policy was updated with a literature search covering the period between January 1996 and February 2004. This 2004 review showed that evidence is still inadequate to reach conclusions about the effectiveness of PENS for the treatment of chronic pain.

The following study selection criteria were used in the 1996 TEC Assessment and the 2004 update:

The literature search revealed 8 randomized trials meeting the above criteria. Of the 8, a total of 5 addressed use of PENS in treating chronic back pain. (2-6) A single study focused on each of these conditions: chronic neck pain (7), chronic diabetic neuropathy (8), and chronic headache. (9) All were designed as randomized crossover studies in which sham PENS was compared with between 1 and 3 types of active PENS, in addition to alternative treatments such as TENS or exercise therapy. Patients would undertake 30-minute treatment sessions, 3 times per week for 2 or 3 weeks. The order of treatments was random. On completing a treatment, a 1-week washout period would follow, then the patient would proceed to another treatment until all patients had received all treatments. Post-treatment outcome was assessed either immediately after completing the last session of a treatment or up to 3 days later. All 8 studies were conducted at 1 institution, the University of Texas Southwestern Medical Center in Dallas.

Chronic Low Back Pain

Chronic low back pain in these 5 studies was defined as persisting for a minimum of either 3 or 6 months. All 5 studies were described as single blinded, and 2 specified that they were investigator blinded. (2, 6) However, the reports provide insufficient details to make clear how investigators achieved blinding or whether such methods of blinding were effective. None of the reports state whether subjects withdrew from the study before its completion. Ghoname et al (2) compared sham PENS, active PENS, and TENS in 64 patients. Active PENS achieved better outcomes than sham PENS on visual analog scale (VAS) pain scores, and daily oral analgesic requirement. Active PENS was better than sham PENS and TENS on physical activity, quality of sleep, and preference. Ghoname et al (3) administered sham PENS, active PENS, TENS, and exercise therapy in 60 patients. Active PENS resulted in better outcomes than all other modalities in terms of VAS pain, analgesic requirements, physical activity, quality of sleep, and preference.

Hamza et al (4) varied the duration of active electrical stimulation at 3 levels (15, 30, and 45 minutes) and compared them with sham stimulation in 75 patients. These investigators confirmed that sham PENS had the least effect, and results were best when the stimulation lasted 30 or 45 minutes. Ghoname et al (5) varied the frequency of the active electrical stimulus at 3 levels, also comparing it with sham stimulation, in 68 patients. One level involved active stimulation with alternating 15-Hz and 30-Hz frequencies, while the other active levels had frequencies of 4 Hz and 100 Hz. The alternating frequency technique had the best results, superior to sham PENS. White et al (6) did not include sham PENS in a study of 72 patients. Rather, this study compared 4 montages, or patterns of needle placement. They found that a bottle-shaped pattern achieved the best results, compared with 3 other patterns. In addition, a 2003 study focused on chronic low back pain in community dwelling older adults. (7) Patients were randomized to receive twice weekly PEN or sham PENS for 6 weeks. At 3-month follow-up, the treatment group reported a significant reduction in pain intensity and disability while the control group did not.

While these studies suggest that active PENS has effects that exceed placebo PENS in the short term, it is unclear whether the study designs included adequate blinding. It is also unclear whether patients withdrew from these studies. Furthermore, the objective of treating chronic low back pain is long-term improvement of pain and functional outcomes, which none of these studies addresses. There is no evidence about the adverse effects of PENS or its acceptability over repeated courses of therapy. Therefore, the available evidence does not permit conclusions about the long-term effectiveness of PENS for treating low back pain. Yokoyama et al found patients randomized to PENS treatment twice per week for 8 weeks had significantly decreased pain levels, physical impairment, and NSAID use, which continued to be present 1 month after treatment completion compared to a second group that received PENS for 4 weeks followed by TENS for 4 weeks and a third group that received only TENS for 8 weeks. (8) While PENS treatment for 8 weeks seemed to demonstrate greater effectiveness in controlling pain for up to 1 month after treatment when compared to the other treatment groups, the beneficial effects were not found at the 2-months follow-up. Weiner and colleagues reported a trial with 200 older adults that had been funded by the National Institutes of Health. (9) Subjects with chronic lower back pain were randomized to PENS or sham-control treatment, with or without physical conditioning/aerobic exercise, twice a week for 6 weeks. Thus, the 4 treatment groups were PENS alone, sham PENS alone, PENS plus physical conditioning, or sham PENS plus physical conditioning. The sham control condition consisted of 10 acupuncture needles in identical locations, depth and duration (30 minutes) as the PENS needles, with brief (5 minute) stimulation at 2 additional needles. Primary and secondary outcome measures were collected at baseline, 1 week and 6 months after treatment by a research associate who was unaware of the treatment. There were no significant adverse effects, and also no differences between the PENS and sham PENS groups in any outcome measure at 1-week or 6-months follow-up. All 4 groups reported reduced pain of a similar level (improvement ranging from 2.3 to 4.1 on the McGill Pain Questionnaire), reduced disability (range of 2.1 to 3.0 on the Roland scale) and improved gait velocity (0.04 to 0.07 m/s) that was maintained for 6 months. Although the authors concluded that minimal electrical stimulation (5 minutes at 2 electrodes) is as effective as usual PENS (30 minutes stimulation from 10 electrodes), the lack of benefit of this treatment over sham control does not provide support for use of PENS in patients with chronic low back pain.

Chronic Neck Pain

One study of 68 patients by White et al (10) compared 2 locations of active stimulation with sham stimulation in 68 patients. Local stimulation involved needle insertion at the neck, while remote stimulation entailed needles placed in the lower back. The sham condition received needles with no electrical stimulation at the neck. Outcomes were assessed immediately after completion of a 3-week treatment period. The local placement of active needles resulted in better pain relief, physical activity, quality of sleep, and analgesic use than local sham treatment or remote active treatment. The authors stated that no side effects were observed at needle insertion sites. The study was described as investigator blinded, but no details were given about the method of blinding. Withdrawals were not noted, and no long-term outcome data were presented. This single study, in which blinding is of uncertain adequacy, does not permit conclusions about the effectiveness of PENS for treating chronic neck pain.

Diabetic Neuropathy

In a crossover study by Hamza et al. (11), 50 patients with diabetic neuropathic pain for at least 6 months were randomized to receive either sham PENS or active PENS first in a 7-week study. Outcome was assessed 1 day after completion of a 3-week treatment period. Active PENS resulted in better outcomes on VAS pain, activity, sleep, and analgesic use, compared with sham PENS. The authors describe the study as investigator blinded, without providing details of how blinding was attempted. Thus, it is uncertain whether blinding was adequate. Withdrawals were not mentioned. Also, no long-term outcome data were presented, so long-term effects are unknown. This single study, which may not have been adequately blinded, does not allow conclusions about the effects of PENS for treating diabetic neuropathy.

Headache

Ahmed et al. (12) conducted a crossover study in 30 patients with longstanding headaches of 3 types: tension, migraine, and post-traumatic injury. Two-week courses of active and sham PENS were compared. Outcomes were assessed at the completion of each treatment. Active PENS achieved better outcomes than sham PENS in terms of VAS pain, physical activity, and quality of sleep. Results did not vary by headache type. The investigators stated that the study was single-blinded, but gave no details about blinding methods or whether withdrawals occurred. The report offers no long-term outcome data. This study does not establish the effectiveness of PENS for treatment chronic headache.

Osteoarthritis of the Knee
In 2007 Kang et al. reported a single-blinded trial that included 70 patients with knee osteoarthritis randomized to stimulation (at the highest tolerable intensity) or placement of electrodes (without stimulation). (13) Patients in the sham group were informed that they would not perceive the normal “pins and needles” with this new device. Patients received one treatment and were followed for one week. The neuromodulation group had 100% follow-up; 7 of 35 (20%) patients from the sham group dropped out. VAS pain scores improved immediately after active (from 5.4 to 3.2), but not sham (5.6 to 4.9) treatments. VAS scores (4.6 vs. 5.2) were not significantly different for the two groups at 48 hours after treatment. Changes in the Western Ontario and McMaster Osteoarthritis Index (WOMAC) were significantly better for the category of stiffness (1 point change vs. 0 point change) but not for pain or function at 48 hours. Measures of patient satisfaction were significantly higher in the neuromodulation group (e.g., 77% vs. 11% good to excellent) at up to 1-week follow-up. Interpretation is limited by the discrepancy between patient satisfaction ratings and 48-hour VAS pain scores, and the differential loss to follow-up in the two groups. These results raise questions about the effectiveness of the blinding, the contribution of short-term pain relief and placebo effects, and the duration of the treatment effects.

Percutaneous Neuromodulation

From its description, neuromodulation appears to be a variant of PENS, varying in length of the needle and its placement at specific anatomical landmarks in the back, instead of specifically at the site of pain. A literature search identified 1 abstract focusing on neuromodulation. This study was an uncontrolled case series of 83 patients with low back pain. While pain improved at 5-week follow-up, the lack of a control group precludes scientific assessment. (14)

Medicare Coverage Policy
The Centers for Medicare and Medicaid Services (CMS) currently has the following national coverage policy on PENS (15):
35-46 ASSESSING PATIENT'S SUITABILITY FOR ELECTRICAL NERVE STIMULATION THERAPY
“Electrical nerve stimulation is an accepted modality for assessing a patient's suitability for ongoing treatment with a transcutaneous or an implanted nerve stimulator. Accordingly, program payment may be made for the following techniques when used to determine the potential therapeutic usefulness of an electrical nerve stimulator:
B. Percutaneous Electrical Nerve Stimulation (PENS).--This diagnostic procedure which involves stimulation of peripheral nerves by a needle electrode inserted through the skin is performed only in a physician's office, clinic, or hospital outpatient department. Therefore, it is covered only when performed by a physician or incident to physician's service. If pain is effectively controlled by percutaneous stimulation, implantation of electrodes is warranted.
As in the case of TENS (described in subsection A), generally the physician should be able to determine whether the patient is likely to derive a significant therapeutic benefit from continuing use of an implanted nerve stimulator within a trial period of 1 month. In a few cases, this determination may take longer to make. The medical necessity for such diagnostic services that are furnished beyond the first month must be documented.
NOTE: Electrical nerve stimulators do not prevent pain but only alleviate pain as it occurs. A patient can be taught how to employ the stimulator, and once this is done, can use it safely and effectively without direct physician supervision. Consequently, it is inappropriate for a patient to visit his/her physician, physical therapist, or an outpatient clinic on a continuing basis for treatment of pain with electrical nerve stimulation. Once it is determined that electrical nerve stimulation should be continued as therapy and the patient has been trained to use the stimulator, it is expected that a stimulator will be implanted or the patient will employ the TENS on a continual basis in his/her home. Electrical nerve stimulation treatments furnished by a physician in his/her office, by a physical therapist or outpatient clinic are excluded from coverage by §1862(a)(1) of the Act. (See §160.7 for an explanation of coverage of the therapeutic use of implanted peripheral nerve stimulators under the prosthetic devices benefit. See §280.13 for an explanation of coverage of the therapeutic use of TENS under the durable medical equipment benefit.)

 

References:

1. 1996 TEC Assessments, Tab 21.
2. Ghoname EA, White PF, Ahmed HE et al. Percutaneous electrical nerve stimulation: an alternative to TENS in the management of sciatica. Pain 1999; 83(2):193-9.
3. Ghoname EA, Craig WF, White PF et al. Percutaneous electrical nerve stimulation for low back pain: a randomized crossover study. JAMA 1999; 281(9):818-23.
4. Hamza MA, Ghoname EA, White PF et al. Effect of the duration of electrical stimulation on the analgesic response in patients with low back pain. Anesthesiology 1999; 91(6):1622-7.
5. Ghoname ES, Craig WF, White PF et al. The effect of stimulus frequency on the analgesic response to percutaneous electrical nerve stimulation in patients with chronic low back pain. Anesth Analg 1999; 88(4):841-6.
6. White PF, Ghoname EA, Ahmed HE et al. The effect of montage on the analgesic response to percutaneous neuromodulation therapy. Anesth Analg 2001; 92(2):483-7.
7. Weiner DK, Rudy TE, Glick RM et al. Efficacy of percutaneous electrical nerve stimulation for the treatment of chronic low back pain in older adults. J Am Geriatr Soc 2003; 51(5):599-608.
8. Yokoyama M, Sun X, Oku S et al. Comparison of percutaneous electrical nerve stimulation with transcutaneous electrical nerve stimulation for long-term pain relief in patients with chronic low back pain. Anesth Analg 2004; 98(6):1552-6.
9. Weiner DK, Perera S, Rudy TE et al. Efficacy of percutaneous electrical nerve stimulation and therapeutic exercise for older adults with chronic low back pain: a randomized controlled trial. Pain 2008; 140(2):344-57.
10. White PF, Craig WF, Vakharia AS et al. Percutaneous neuromodulation therapy: does the location of electrical stimulation affect the acute analgesic response? Anesth Analg 2000; 91(4):949-54.
11. Hamza MA, White PF, Craig WF et al. Percutaneous electrical nerve stimulation: a novel analgesic therapy for diabetic neuropathic pain. Diabetes Care 2000; 23(3):365-70.
12. Ahmed HE, White PF, Craig WF et al. Use of percutaneous electrical nerve stimulation (PENS) in the short-term management of headache. Headache 2000; 40(4):311-5.
13. Kang RW, Lewis PB, Kramer A et al. Prospective randomized single-blinded controlled clinical trial of percutaneous neuromodulation pain therapy device versus sham for the osteoarthritic knee: a pilot study. Orthopedics 2007; 30(6):439-45.
14. Condon JE, Borg-Stein J, Revord J et al. A multicenter trial of percutaneous neuromodulation therapy for low back pain patients with a subacute duration of lower extremity pain. Presented at the American Academy of Pain Medicine Annual Meeting. San Francisco, CA, March 1, 2002.

15. Medicare Coverage Issues Manual. Section 35-46: Assessing Patient's Suitability for Electrical Nerve Stimulation Therapy. Available online at http://www.cms.hhs.gov/manuals/06_cim/ci35.asp.

 

Index

Policy History

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