Medical Policies - Medicine
Interferential Current Stimulation
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Interferential current stimulation is considered experimental, investigational and/or unproven.
Interferential current stimulation (IFS) is a type of electrical stimulation that uses paired electrodes of 2 independent circuits carrying high-frequency (4000 Hz) and medium-frequency (150 Hz) 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, and treat a variety of gastrointestinal disorders. There are no standardized protocols for the use of IFS; IFS may vary by frequency of stimulation, the pulse duration, treatment time, and electrode-placement technique.
A number of interferential stimulator devices have been cleared for marketing by the United States (U.S.) Food and Drug Administration (FDA), through the 510(k) process, including the Medstar™ 100 (MedNet Services) and the RS-4i® (RS Medical).
Randomized controlled trials (RCTs) with placebo control are extremely important to assess treatments of painful conditions, due to the expected placebo effect, the subjective nature of pain assessment in general, and the variable natural history of pain that often responds to conservative care. Therefore, to establish whether an intervention for pain is effective, a placebo comparison is needed.
A 2015 network meta-analysis by Zeng et al. identified 27 RCTs on 5 types of electrical stimulation therapies used to treat pain in patients with knee osteoarthritis. (1) Zeng found that interferential current stimulation (IFS) was significantly more effective than control interventions for pain relief (standardized mean difference [SMD], 2.06; 95% credible interval [CrI], 1.10 to 3.19) and pain intensity (SMD = -0.92; 95% CrI, -1.72 to -0.05). The validity of these conclusions is uncertain due to the limitations of network meta-analysis that uses indirect comparisons to make conclusions. A further limitation of this analysis is that the findings of placebo-controlled studies were not reported separately; rather, they were pooled in analysis of usual care comparators.
In 2010, Fuentes et al. published a systematic review and meta-analysis of RCTs evaluating the effectiveness of IFS for treating musculoskeletal pain. (2) Twenty RCTs met the following inclusion criteria: adults diagnosed with a painful musculoskeletal condition (e.g., knee, back, joint, shoulder or osteoarthritic pain); compared IFS alone or as a co-intervention to placebo, no treatment, or an alternative intervention; and assessed pain using a numeric rating scale. Fourteen of the trials reported data that could be included in a pooled analysis. IFS as a stand-alone intervention was not found to be more effective than placebo or an alternative intervention at reducing pain. For example, a pooled analysis of 2 studies comparing IFS alone and placebo did not find a statistically significant difference in pain intensity at discharge; the pooled mean difference (MD) was 1.17 (95% confidence interval [CI], -1.70 to 4.05). In addition, a pooled analysis of 2 studies comparing IFS alone and an alternative intervention (e.g., traction or massage) did not find a significant difference in pain intensity at discharge; the pooled MD was -0.16 (95% CI, -0.62 to 0.31). Moreover, in a pooled analysis of 5 studies comparing IFS as a co-intervention to a placebo group, there was a nonsignificant finding (MD=1.60; 95% CI, -0.13 to 3.34). The meta-analysis found IFS plus another intervention to be superior to a control group (e.g., no-treatment) for pain intensity at day 1 and 4 weeks; a pooled analysis of 3 studies found an MD of 2.45 (95% CI, 1.69 to 3.22; p<0.001). However, that analysis did not distinguish the specific effects of IFS from the co-intervention nor did it control for potential placebo effects.
Two placebo-controlled RCTs were included in the Fuentes meta-analysis, one of which (Defrin et al., 2005) (3) was also included in the Zeng meta-analysis. The trial by Defrin included a total of 62 patients with osteoarthritic knee pain. (3) Patients were randomly assigned to 1 of 6 groups (there were 4 active treatment groups and 2 control groups, sham and nontreated). Acute pre- versus posttreatment reductions in pain were found in all active groups but neither control group. Stimulation resulted in a modest pretreatment elevation of pain threshold over this 4week trial. In 1987, Taylor et al. randomly assigned 40 patients with temporomandibular joint syndrome or myofascial pain syndrome to either active or placebo IFS. (4) Principal outcomes were pain assessed by a questionnaire and range of motion (ROM). There were no statistically significant differences in the outcomes between the 2 groups.
Two more recent RCTs, both published in 2012, were included in the Zeng meta-analysis. One found significantly better outcomes with IFS versus placebo while the other did not find significant differences between active and sham interventions. Atamaz et al. compared IFS, transcutaneous electrical nerve stimulation (TENS), shortwave diathermy and sham interventions for treating knee osteoarthritis. (5) A total of 203 patients were randomized to 1 of 6 groups, 3 with active treatment and 3 with sham treatment. The primary outcome was a 0 to 100 visual analog scale (VAS) assessing knee pain. Other outcomes included range of motion, time to walk 15 meters, paracetamol intake, the Nottingham Health Profile (NHP) score, and the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) score. At the 1-, 3-, and 6-month follow-up, there was not a statistically significant difference among the 6 groups in the VAS pain score, NHP pain score, or WOMAC pain score. Moreover, WOMAC function score, time to walk 15 meters, and NHP physical mobility score did not differ significantly among groups at any of the follow-up assessments. At the 1-month follow-up, paracetamol intake was significantly lower in the IFS group than in the TENS group.
Gundog et al. randomly assigned 60 patients with knee osteoarthritis to 1 of 4 groups; 3 IFS groups at frequencies of 40 Hz, 100 Hz, and 180 Hz, or sham IFS. (8) The primary outcome was pain intensity assessed by the WOMAC. Mean WOMAC scores 1 month after treatment were 7.2 in the 40-Hz group, 6.7 in the 100-Hz group, 7.8 in the 180-Hz group, and 16.1 in the sham IFS group (p<0.05 versus active treatment groups). Secondary outcomes (e.g., VAS score) also showed significantly higher benefit in the active treatment groups compared to the sham IFS group. The number of patients assigned to each group and patient follow-up rates were not reported.
In addition to the placebo-controlled trials, several RCTs have compared IFS to another active intervention or to usual care. (7-11) However, studies with active comparators, as well as those with usual care control groups may be subject to the placebo effect. Receiving an older or known, rather than a novel, intervention, may elicit a placebo response.
Section Summary: Musculoskeletal Conditions
Placebo-controlled RCTs of IFS for treating musculoskeletal pain and impaired function have mostly found that it does not significantly improve outcomes. A meta-analysis limited to placebo-controlled trials also did not find a significant benefit of IFS for treating pain and function. RCTs with usual care or active treatment comparisons may be subject to the placebo effect.
Several RCTs evaluating IFS for treating children with constipation and/or other lower gastrointestinal symptoms were identified. The RCTs had small sample sizes and did not consistently find a benefit of interferential stimulation. For example, in 2012, Kajbafzadeh et al. in Iran randomized 30 children with intractable constipation to receive IFS or sham stimulation. (12) Children ranged in age from 3 to 12 years old, and all had failed 6 months of conventional therapy, e.g., dietary changes and laxatives. Patients received fifteen 20-minute IFS sessions, 3 times a week over 5 weeks. Over 6 months, the mean frequency of defecation increased from 2.5 times per week to 4.7 times per week in the treatment group and from 2.8 times per week to 2.9 times per week in the control group. The mean pain during defecation score decreased from 0.35 to 0.20 in the treatment group and from 0.29 to 0.22 in the control group. The authors reported a statistically significant between-group difference in constipation symptoms.
Another RCT, published by Clarke et al. in 2009, was conducted in Australia. (13) Thirty-three children with slow transit constipation (mean age, 12 years) were randomized to receive IFS or sham treatment. They received twelve 20-minute sessions over 4 weeks. The primary outcome was health-related quality of life and the main assessment instrument used was the Pediatric Quality of Life Inventory (PedsQL). The authors only reported within-group changes; they did not compare the treatment and control groups. There was no statistically significant change in QOL, as perceived by the parent group. The mean parent-reported QOL scores changed from 70.3 to 70.1 in the active treatment group and from 69.8 to 70.2 in the control group. There was also no significant difference in QOL, as perceived by the child after sham treatment. PedQL score, as perceived by the child, did increase significantly in the active treatment group (mean of 72.9 pretreatment and 81.1 posttreatment, p=0.005).
Irritable Bowel Disease
A 2012 RCT by Coban et al. randomized 67 adults with irritable bowel syndrome to active or placebo IFS. (14) Patients with functional dyspepsia were excluded. Patients received four 15-minute IFS sessions over 4 weeks. Fifty-eight of 67 (87%) patients completed the study. One month after treatment, primary outcomes measures did not differ significantly between the treatment and control groups. For example, for abdominal discomfort, the response rate (i.e., >50% improvement) was 68% in the treatment group and 44% in the control group. For bloating and discomfort, the response rate was 48% in the treatment group and 46% in the placebo group. Using a VAS measure, 72% of the treatment group and 69% of the control group reported improvement in abdominal discomfort.
One RCT, by Koklu et al. in Turkey, evaluated IFS for treating dyspepsia. (15) The trial randomized patients to active IFS (n=25) or sham treatment (n=25); patients were unaware of treatment allocation. There were 12 treatment sessions over 4 weeks; each session lasted 15 minutes. A total of 44 of 50 (88%) randomized patients completed the therapy session and follow-up questionnaires at 2 and 4 weeks. The authors did not specify primary outcome variables; they measured the frequency of 10 gastrointestinal symptoms. In an intention-to-treat (ITT) analysis at 4 weeks, IFS was superior to placebo for the symptoms of early satiation and heartburn, but not for the other 8 symptoms. For example, before treatment, 16 of 25 (64%) patients in each group reported experiencing heartburn. At 4 weeks, 9 patients (36%) in the treatment group and 13 patients (52%) in the sham group reported heartburn (p=0.02). Among symptoms that did not differ at follow-up between groups, 24 of 25 patients (96%) in each group reported epigastric discomfort before treatment. In the ITT analysis, 5 of 25 patients (20%) in the treatment group and 6 of 25 (24%) patients in the placebo group reported epigastric discomfort.
Section Summary: Gastrointestinal Disorders
IFS has been tested for a variety of gastrointestinal (GI) conditions, with a small number of trials completed for each condition. Trial results are mixed, with some reporting benefit and others not. This body of evidence is inconclusive on whether IFS is an efficacious treatment for GI conditions.
A single-blind RCT evaluating IFS as a treatment of chronic stroke was published by Suh et al. in 2014. (16) Forty-two inpatient stroke patients with plantarflexor spasticity were randomized to a single 60-minute session with IFS or placebo IFS treatment following 30 minutes of standard rehabilitation. In the placebo treatment, electrodes were attached but current not applied. Outcomes were measured immediately before and 1 hour after the intervention. The primary outcomes were gastrocnemius spasticity measured on a 0 to 5 Modified Ashworth Scale and 2 balance-related measures: the Functional Reach Test and the Berg Balance Scale. In addition, gait speed was measured using a 10-meter walk test, and gait function was assessed with the Timed Up and Go Test. The IFS group performed significantly better than the placebo group on all outcomes (p<0.05 for each comparison). For example, the mean (SD) difference in the Modified Ashworth Scale was 1.55 (0.76) in the IFS group and 0.40 (0.50) in the placebo group. A major limitation of the study was that outcomes were only measured 1 hour after the intervention and no data were available on longer term impacts of the intervention.
Section Summary: Poststroke Spasticity
Data from 1 small RCT with very short follow-up provides insufficient evidence on the impact of IFS on health outcomes in patients with chronic stroke.
Ongoing and Unpublished Clinical Trials
Some currently unpublished trials that might influence this review are listed in Table 1.
Table 1. Summary of Key Trials
Efficacy of Interferential Therapy in Chronic Constipation (CON-COUR)
NCT: national clinical trial.
Summary of Evidence
For individuals who have musculoskeletal conditions who receive interferential current stimulation (IFS), the evidence includes randomized controlled trials (RCTs) and meta-analyses. Relevant outcomes are symptoms, functional outcomes, quality of life, medication use, and treatment-related morbidity. Placebo-controlled RCTs of IFS for treating musculoskeletal pain and impaired function have mostly found that it does not significantly improve outcomes and a meta-analysis of placebo-controlled trials did not find a significant benefit of IFS for decreasing pain or improving function. The evidence is insufficient to determine the effects of the technology on health outcomes.
For individuals who have gastrointestinal disorders who receive IFS, the evidence includes RCTs. Relevant outcomes are symptoms, functional outcomes, quality of life, medication use and treatment- related morbidity. IFS has been tested for a variety of gastrointestinal conditions, with a small number of trials completed for each condition. Trials results are mixed, with some reporting benefit and others not. This body of evidence is inconclusive on whether IFS is an efficacious treatment for gastrointestinal conditions. The evidence is insufficient to determine the effects of the technology on health outcomes.
For individuals who have poststroke spasticity who receive IFS, the evidence includes 1 RCT. Relevant outcomes are symptoms, functional outcomes, quality of life, and treatment-related morbidity. The RCT has a small sample size and very short follow-up (immediately posttreatment). The evidence is insufficient to determine the effects of the technology on health outcomes.
Practice Guidelines and Position Statements
American College of Physicians and the American Pain Society
Clinical practice guidelines from the American College of Physicians and the American Pain Society, published in 2007, concluded that there was insufficient evidence to recommend interferential current stimulation (IFS) for the treatment of low back pain. (17)
American College of Occupational and Environmental Medicine
The American College of Occupational and Environmental Medicine published several relevant guidelines in 2011:
• Shoulder disorders: The guideline stated that the evidence on IFS is insufficient and, depending on the specific disorder, either did not recommend IFS or were neutral on whether to recommend it. (18)
• Low back disorders: The guideline stated that the evidence on IFS is insufficient and the intervention is not recommended. The exception is that IFS may be considered as an option on a limited basis for acute low back pain with or without radicular pain. (19)
• Knee disorders: The guideline stated that IFS is recommended for postoperative anterior cruciate ligament reconstruction, meniscectomy, and knee chondroplasty immediately postoperatively in the elderly. This was a level C recommendation. (20)
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The following codes may be applicable to this Medical policy and may not be all inclusive.
64550, 97014, 97032, 97139
E1399, G0283, S8130, S8131
ICD-9 Diagnosis Codes
Refer to the ICD-9-CM manual
ICD-9 Procedure Codes
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ICD-10 Diagnosis Codes
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ICD-10 Procedure Codes
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1. Zeng C, Li H, Yang T, et al. Electrical stimulation for pain relief in knee osteoarthritis: systematic review and network meta-analysis. Osteoarthritis Cartilage. Feb 2015; 23(2):189-202. PMID 25497083
2. Fuentes JP, Armijo Olivo S, Magee DJ, et al. Effectiveness of interferential current therapy in the management of musculoskeletal pain: a systematic review and meta-analysis. Phys Ther. Sep 2010; 90(9):1219-1238. PMID 20651012
3. Defrin R, Ariel E, Peretz C. Segmental noxious versus innocuous electrical stimulation for chronic pain relief and the effect of fading sensation during treatment. Pain. May 2005; 115(1-2):152-160. PMID 15836978
4. Taylor K, Newton RA, Personius WJ, et al. Effects of interferential current stimulation for treatment of subjects with recurrent jaw pain. Phys Ther. Mar 1987; 67(3):346-350. PMID 3493493
5. Atamaz FC, Durmaz B, Baydar M, et al. Comparison of the efficacy of transcutaneous electrical nerve stimulation, interferential currents, and shortwave diathermy in knee osteoarthritis: a double-blind, randomized, controlled, multicenter study. Arch Phys Med Rehabil. May 2012; 93(5):748-756. PMID 22459699
6. Gundog M, Atamaz F, Kanyilmaz S, et al. Interferential current therapy in patients with knee osteoarthritis: comparison of the effectiveness of different amplitude-modulated frequencies. Am J Phys Med Rehabil. Feb 2012; 91(2):107-113. PMID 22019968
7. Koca I, Boyaci A, Tutoglu A, et al. Assessment of the effectiveness of interferential current therapy and TENS in the management of carpal tunnel syndrome: a randomized controlled study. Rheumatol Int. Dec 2014; 34(12):1639-1645. PMID 24728028
8. Lara-Palomo IC, Aguilar-Ferrandiz ME, Mataran-Penarrocha GA, et al. Short-term effects of interferential current electro-massage in adults with chronic non-specific low back pain: a randomized controlled trial. Clin Rehabil. May 2013; 27(5):439-449. PMID 23035006
9. Facci LM, Nowotny JP, Tormem F, et al. Effects of transcutaneous electrical nerve stimulation (TENS) and interferential currents (IFC) in patients with nonspecific chronic low back pain: randomized clinical trial. Sao Paulo Med J. 2011; 129(4):206-216. PMID 21971895
10. Albornoz-Cabello M, Maya-Martin J, Dominguez-Maldonado G, et al. Effect of interferential current therapy on pain perception and disability level in subjects with chronic low back pain: A randomized controlled trial. Clin Rehabil. Mar 14 2016. PMID 26975312
11. Dissanayaka TD, Pallegama RW, Suraweera HJ, et al. Comparison of the effectiveness of transcutaneous electrical nerve stimulation and interferential therapy on the upper trapezius in myofascial pain syndrome: a randomized controlled study. Am J Phys Med Rehabil. Mar 4 2016. PMID 26945216
12. Kajbafzadeh AM, Sharifi-Rad L, Nejat F, et al. Transcutaneous interferential electrical stimulation for management of neurogenic bowel dysfunction in children with myelomeningocele. Int J Colorectal Dis. Apr 2012; 27(4):453-458. PMID 22065105
13. Clarke MC, Chase JW, Gibb S, et al. Improvement of quality of life in children with slow transit constipation after treatment with transcutaneous electrical stimulation. J Pediatr Surg. Jun 2009; 44(6):1268-1272; discussion 1272. PMID 19524752
14. Coban S, Akbal E, Koklu S, et al. Clinical trial: transcutaneous interferential electrical stimulation in individuals with irritable bowel syndrome - a prospective double-blind randomized study. Digestion. 2012; 86(2):86-93. PMID 22846190
15. Koklu S, Koklu G, Ozguclu E, et al. Clinical trial: interferential electric stimulation in functional dyspepsia patients - a prospective randomized study. Aliment Pharmacol Ther. May 2010; 31(9):961-968. PMID 20136803
16. Suh HR, Han HC, Cho HY. Immediate therapeutic effect of interferential current therapy on spasticity, balance, and gait function in chronic stroke patients: a randomized control trial. Clin Rehabil. Sep 2014; 28(9):885-891. PMID 24607801
17. 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. Oct 2 2007; 147(7):478-491. PMID 17909209
18. American College of Occupational and Environmental Medicine (ACOEM). Shoulder Disorders. Available at <http:www.guideline.gov> (accessed 2016 May 15).
19. American College of Occupational and Environmental Medicine (ACOEM). Low Back Disorders. Available at <http:www.guideline.gov> (accessed 2016 May 15).
20. American College of Occupational and Environmental Medicine (ACOEM). Knee Disorders. Available at <http:www.guideline.gov> (accessed 2016 May 15).
21. Interferential Stimulation for Treatment of Pain. Chicago, Illinois: Blue Cross Blue Shield Association Medical Policy Reference Manual (June 2016) Durable Medical Equipment 1.01.24.
|10/15/2017||Reviewed. No changes.|
|11/1/2016||Document updated with literature review. Coverage unchanged.|
|4/15/2015||Reviewed. No changes.|
|6/1/2014||New medical document. Coverage is unchanged: Interferential current stimulation is considered experimental, investigational and/or unproven. This topic was previously addressed on MED201.026 Surface Electrical Stimulation.|
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