Durable Medical Equipment Section - Interferential Stimulation

IMPORTANT REMINDER

This Medical Policy has been developed through consideration of medical necessity, generally accepted standards of medical practice, and review of medical literature and government approval status.

Benefit determinations should be based in all cases on the applicable contract language. To the extent there are any conflicts between these guidelines and the contract language, the contract language will control.

The purpose of medical policy is to provide a guide to coverage. Medical Policy is not intended to dictate to providers how to practice medicine. Providers are expected to exercise their medical judgment in providing the most appropriate care.

Description

Interferential stimulation (IFS) is a type of electrical stimulation that uses paired electrodes of two independent circuits carrying high-frequency (4000 Hz) and medium-frequency alternating currents. The superficial electrodes are aligned on the skin around the affected area.  It is believed that IFS permeates the tissues more effectively and, with less unwanted stimulation of cutaneous nerves, is more comfortable than transcutaneous electrical stimulation (TENS). Interferential stimulation has been investigated as a technique to reduce pain, improve range of motion, or promote local healing following various tissue injuries. There are no standardized protocols for the use of interferential therapy; the therapy may vary according to the frequency of stimulation, the pulse duration, treatment time, and electrode-placement technique.

Policy/Criteria

Interferential current stimulation is considered investigational.

Scientific Background

As with any treatment focused on pain relief, randomized, placebo-controlled trials are particularly important to determine if any treatment effect exceeds the expected treatment effect. A literature search based on the MEDLINE database identified four randomized trials (2-7), of which three were placebo-controlled. (2,4) The trials are reviewed briefly below.

Taylor and colleagues randomized 40 patients with temporomandibular joint syndrome or myofascial pain syndrome to undergo either active or placebo interferential stimulation. (2) The principal outcomes were pain assessed by a questionnaire and range of motion (ROM). There was no statistically significant difference in the outcomes between the two groups.

Van der Heijden and colleagues randomized 180 patients with soft tissue shoulder disorders to undergo therapy in one of the following groups in addition to a program of exercise therapy:

1. Interferential therapy plus ultrasound
2. Active interferential therapy plus dummy ultrasound
3. Dummy interferential therapy plus active ultrasound
4. Dummy interferential therapy plus dummy ultrasound (i.e., the placebo group)
5. No adjuvant therapy. (3)

Principal outcome measures include recovery, functional status, chief complaint, pain, clinical status, and range of motion at six weeks after the therapy was completed and at intervals up to one year. The authors reported that neither interferential therapy nor ultrasound proved to be effective as adjuvants to exercise therapy.  Zambito and colleagues randomized 26 men and 94 women with chronic low back pain associated with either degenerative disk disease or previous multiple vertebral osteoporotic fractures to one of three groups.  Group 1 received interferential therapy (IFT), group 2 received horizontal therapy (HT), another form of electrical stimulation and group 3 received sham HT.  At two weeks follow-up all three groups reported a similar, significant improvement in both pain and function scores.  However, at week six and fourteen the two active groups showed significant improvement over baseline and over the sham group which had returned to baseline scores.  The use of analgesic medications improved significantly only in the HT group.  These results have not been duplicated in other studies.

Werners and colleagues reported on the results of a study that randomized 152 patients with low back pain to either treatment with interferential therapy or traction. (5) Therefore, this study was not placebo-controlled. Outcomes were based on the results of the Oswestry Disability Index and a pain visual analog scale. The authors reported that both groups recorded improvements over a 3-month period; there was no statistically significant difference in outcomes between the two groups. Without a placebo group, it is unknown whether the improvement is related to the natural history of the disease or any intervention.

Hurley and colleagues randomly assigned 60 patients with back pain to one of three groups:

1. Interferential therapy of the painful area
2. Interferential therapy of the spinal nerve
3. A control group, who received no interferential therapy. (6)

There was no placebo group. All patients received educational materials. Those assigned to active treatment groups received 2–3 treatments per week for variable periods of time. The principal outcome measures were based on results of pain-rating index and the Roland-Morris Disability Questionnaire. Placement of the interferential therapy electrodes over the spinal nerve, compared to the painful area, resulted in a significantly larger reduction in disability scores. However, the lack of a placebo group limits interpretation of these data.

In a randomized trial, Hou and colleagues studied a various combination of therapies in a group of 119 patients with myofascial disease and active trigger points, including hot packs, "stretch and spray," ischemic compression, myofascial release, and interferential therapy. (7) There was no control or placebo group, and thus interpretation of the data is limited. Poitras and Brosseau conducted a Cochrane-structured systematic review of management of back pain with therapeutic modalities including transcutaneous electrical nerve stimulation and interferential current. (8) The authors found no eligible studies on which to base recommendations for interferential stimulation.

A randomized double-blind trial compared IFS or horizontal therapy (HT) with sham stimulation in 105 older women with chronic low back pain due to multiple vertebral fractures. (9) All participants received a full therapeutic exercise program, and blinded evaluation revealed no differences between the groups following 2 weeks of active or sham stimulation. However, the active stimulation groups showed post-treatment improvements of about 30% in visual analog scores (VAS) for pain and in the Backill score at the six and fourteen week follow-up evaluations. Analgesic consumption decreased by 47%, 57%, and 31%, in the IF, HT, and control groups, respectively. The proportion of patients who improved in the HT group was greater than in the sham HT group (odds ratio, OR = 0.34, 95% CI 0.13-0.91), but did not achieve statistical significance for the IFS group (odds ratio, OR = 0.49, 95% CI 0.18-1.29). Additional study is needed.

Clinical practice guidelines from the American College of Physicians and the American Pain Society concluded that there was insufficient evidence to recommend interferential stimulation for the treatment of low back pain. (10)

In summary, the results from the majority of placebo-controlled trials have reported negative findings of interferential therapy.  An updated search of the MEDLINE database through February 11, 2008 did not reveal any additional data from randomized, placebo-controlled trials that alter the conclusions reached above.

References

1. BlueCross and BlueShield Association Medical Policy Reference Manual, Policy No. 1.01.24
2. Taylor K, Newton RA, Personius WJ et al. Effects of interferential current stimulation for treatment of subjects with recurrent jaw pain. Phys Ther 1987;67(3):346-50
3. van der Heijden GJ, Leffers P, Wolters PJ et al. No effect of bipolar interferential electrotherapy and pulsed ultrasound for soft tissue disorders: a randomised controlled trial. Ann Rheum Dis 1999;58(9):530-50
4. Zambito A, Bianchini D, Gatti D, et al. Interferential and horizontal therapies in chronic low back pain: a randomized, double blind, clinical study. Clin Exp Rheumatol. 2006;24(5):534-9
5. Werners R, Pynsent PB, Bulstrode CJ. Randomized trial comparing interferential therapy with motorized lumbar traction and massage in the management of low back pain in a primary care setting. Spine 1999;24(15):1579-84
6. Hurley DA, Minder PM, McDonough SM et al. Interferential therapy electrode placement technique in acute low back pain: a preliminary investigation. Arch Phys Med Rehabil 2001;82(4):485-93
7. Hou CR, Tsai LC, Cheng KF et al. Immediate effects of various physical therapeutic modalities on cervical myofascial pain and trigger-point sensitivity. Arch Phys Med Rehabil 2002;83(10):1406-14
8. Poitras S, Brosseau L. Evidence-informed management of chronic low back pain with transcutaneous electrical nerve stimulation, interferential current, electrical muscle stimulation, ultrasound, and thermotherapy. Spine J 2008;8(1):226-33
9. Zambito A, Bianchini D, Gatti D, et al. Interferential and horizontal therapies in chronic low back pain due to multiple vertebral fractures: a randomized, double blind, clinical study. Osteoporos Int 2007;18(11):1541-5
10. Chou R, Qaseem A, Snow V et al. Diagnosis and treatment of low back pain: a joint clinical practice guideline from the American College of Physicians and the American Pain Society. Ann Intern Med 2007;147(7):478-91

Cross References

Electrical Stimulation Devices for Home Use; Regence Medical Policy Manual, DME, Policy No. 11

Sympathetic Therapy for the Treatment of Pain; Regence Medical Policy Manual, DME, Policy No. 65

Electrostimulation and Electromagnetic Therapy for the Treatment of Chronic Wounds in the Home Setting; Regence Medical Policy Manual, DME, Policy No. 67

Functional Neuromuscular Stimulation to Provide Ambulation, Regence Medical Policy Manual, DME, Policy No. 56

Threshold Electrical Stimulation as a Treatment of Motor Disorders, Regence Medical Policy Manual, DME, Policy No. 57

Electrical Stimulation for the Treatment of Arthritis, Regence Medical Policy Manual, DME, Policy No. 70

Percutaneous Neuromodulation Therapy (PNT), Regence Medical Policy Manual, Surgery, Policy No. 44

Spinal Cord Stimulation for Treatment of Pain, Regence Medical Policy Manual, Surgery, Policy No. 45

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