Interferential Current Stimulation
|Durable Medical Equipment||Original Policy Date
Last Review Status/Date
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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 interferential therapy; the therapy may vary according to the frequency of stimulation, the pulse duration, treatment time, and electrode-placement technique.
A number of interferential stimulator devices have received 510(k) marketing clearance from the U.S. Food and Drug Administration (FDA), including the Medstar™ 100 (MedNet Services) and the RS-4i® (RS Medical).
There are no specific CPT codes describing interferential current stimulation. The following CPT codes might be used:
64550: Application of surface (transcutaneous) neurostimulator
97014: Application of a modality to one or more areas; electrical stimulation (unattended)
The following HCPCS code might also be used:
G0283: Electrical stimulation (unattended), to one or more areas for indication(s) other than wound care, as part of a therapy plan of care.
Effective for 2012, the following HCPCS codes are available for these devices:
S8130 Interferential current stimulator, 2 channel
S8131 Interferential current stimulator, 4 channel
BlueCard/National Account Issues
State or federal mandates (e.g., FEP) may dictate that all devices approved by the U.S. Food and Drug Administration (FDA) may not be considered investigational, and thus these devices may be assessed only on the basis of their medical necessity.
This policy was originally created in 2003 and was updated regularly with searches of the MEDLINE database. Most recently, the literature was reviewed through November 10, 2014. Following is a summary of the key literature to date.
Musculoskeletal Pain, Range of Motion, and Function
In 2010, Fuentes et al published a systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating the effectiveness of interferential current stimulation (IFS) for treating musculoskeletal pain.(1) A total of 20 RCTs met the following inclusion criteria: included adults diagnosed with a painful musculoskeletal condition (eg, 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 on a numeric 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 (eg, 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 (eg, no-treatment). A pooled analysis of 3 studies found an MD of 2.45 (95% CI, 1.69 to 3.22). The latter analysis is limited in that the specific effects of IFS versus the cointervention cannot be determined, and it does not control for potential placebo effects.
The 2 trials identified that compared IFS alone to placebo had relatively small sample sizes in each treatment group. A 2005 trial by Defrin et al included a total of 62 patients with osteoarthritic knee pain.(2) 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 not in either control group. Stimulation resulted in a modest pretreatment elevation of pain threshold over the 4 weeks of the study. In 1987, Taylor et al randomly assigned 40 patients with temporomandibular joint syndrome or myofascial pain syndrome to undergo either active or placebo interferential therapy.(3) The principal outcomes were pain assessed by a questionnaire, as well as range of motion (ROM). There were no statistically significant differences in the outcomes between the 2 groups.
Representative recent trials on IFS for treating musculoskeletal pain are described below.
In 2013, Lara-Paloma et al in Spain published data from a single-blind RCT in patients with chronic low back pain that compared massage with IFS (n=31) to superficial massage (n=30).(4) The superficial massage intervention involved gentle techniques using light pressure in the lumbar area. In contrast, in the treatment group, providers could use deeper massage, and dorsolumbar, as well as lumbar areas were massaged. Patients received 20 sessions over 10 weeks; outcomes were assessed by blinded personnel at baseline and immediately after the final session. Sixty of 61 participants completed the study. The primary outcome was change in the score on the Roland-Morris Disability Questionnaire (RMDQ range 0 [no disability] to 24 [severe disability]). Baseline scores on the RMDQ were 10.33 (SD=3) in the massage with IFS group and 11.13 (SD=2.9) in the control group. Posttreatment, scores were 7.96 (SD=3.3) and 10.97 (SD=3.1), respectively. The difference between groups was statistically significant, favoring the intervention group. However, the reduction in RMDQ in the intervention group, 2.37points, did not meet the predefined minimal clinically important difference of 2.5 points. A number of secondary outcomes were also assessed and findings were mixed; the intervention group improved significantly more than the control group on some measures but not others. As with the primary outcome, the absolute change in scores in the intervention group on secondary outcomes tended to be small. For example, on a 10-point visual analog scale (VAS), the mean score in the intervention group was 6.67 (SD=1.67) at baseline and 5.01 (SD=1.89) at follow-up. This change in the VAS score did not reach the predefined threshold for clinical significance of 2.0 points. A limitation in the study design was that the potential impact of IFS could not be isolated because a combination intervention was used. Beneficial effects in the treatment group may have been due to use of deeper or more extensive massage rather than the addition of IFS.
Another study evaluating IFS for treating low back pain used IFS as the sole intervention, and included both an active comparator and a no-treatment control group. Facci et al in Brazil randomized patients to IFS (n=50), transcutaneous electrical nerve stimulation (TENS) (n=50) or a control group (n=40).(5) Patients were assessed by a blinded evaluator before and after completing ten 30-minute treatment sessions over 2 weeks. Patients in the control group were reassessed after 2 weeks. A total of 137 of 150 (91%) patients completed the intervention; analysis was intention to treat. The mean pain intensity, as measured by a 10-point VAS, decreased 4.48 cm in the IFS group, 3.91 cm in the TENS group, and 0.85 cm in the control group. There was not a statistically significant difference in pain reduction in the active treatment groups. Both groups experienced significantly greater pain reduction than the control group. Since a sham treatment was not used, a placebo effect cannot be ruled out when comparing active to control treatments. Moreover, findings from this trial do not demonstrate equivalence between IFS and TENS; studies with larger numbers of patients that are designed as equivalence or noninferiority trials would be needed before drawing this conclusion.
In 2012, Atamaz et al published a double-blind RCT comparing IFS, TENS, and shortwave diathermy for treatment of knee osteoarthritis.(6) 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 VAS assessing knee pain. Other outcomes included range of motion, time to walk 15 meters, paracetamol intake, the Nottingham Health Profile (NHP), and the Western Ontario and McMaster University Osteoarthritis Index (WOMAC). At the 1-, 3-, and 6-month follow-ups, there was no statistically significant difference among the 6 groups in the VAS pain score, WOMAC pain score, or NHP 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 the TENS group.
A 2014 single-blind RCT by Koca et al evaluated IFS for treating symptoms associated with idiopathic carpal tunnel syndrome.(7) Patients were randomized to 1 of 3 groups and received either splint therapy, TENS, or IFS (n=25 per group). Patients in the TENS and IFS groups had a total of 15 therapy sessions (5 per week) lasting 20 minutes each. All patients were permitted to use paracetamol as needed during the study, except on assessment days. Sixty-three of 75 patients (84%) completed the study. The authors assessed a number of outcomes and did not specify primary end points. There were no statistically significant differences in outcomes between TENS and splint therapy. Patients in the IFS group had significantly greater improvement than those in the TENS and splint groups on most reported clinical outcomes, including pain measured on a 10-point VAS, symptom severity, and functional capacity. For example, 6-week VAS scores were a mean of 4.80 (SD=1.18) in the IFS group, 6.37 (SD=1.18) in the splint group, and 6.68 (SD=1.42) in the TENS group (p<0.01 for the comparison between IFS and each of the other groups). The study was limited by the small sample size and high drop-out rate.
A large number of RCTs have been performed using IFS for musculoskeletal conditions. These have varied in the adjunct treatments that are used, comparison groups, types of controls, and outcome measures. Many of these trials have methodologic limitations such as an inadequate placebo control and/or the use of multiple treatment modalities without the ability to isolate the incremental effect of IFS. While some of these studies have reported benefit, the majority do not. A meta-analysis of RCTs did not find a significant benefit of IFS over control for treating pain. The body of evidence suggests, although is not definitive, that IFS is not efficacious for improving pain, function and/or ROM for patients with musculoskeletal conditions.
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.(8) Children ranged in age from 3 to 12 years old, and all had failed 6 months of conventional therapy, eg, dietary changes and laxatives. Patients received fifteen 20-minute 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 that there was a statistically significant difference between groups in constipation symptoms.
Another RCT was published by Clarke et al in 2009; the study was conducted in Australia.(9) 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 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 not a statistically significant change in QOL, as perceived by the parent in either the active or sham treatment group. The mean parentally perceived 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. The score on the PedQL group 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
An RCT with adults was published in 2012 by Coban et al in Turkey.(10) The authors randomized 67 individuals with irritable bowel syndrome to active or placebo IFS. Patients with functional dyspepsia were excluded. Patients received a total of four 15-minute 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. Treatment response was defined as more than a 50% improvement in symptoms. For the symptom of abdominal discomfort, for example, the response rate 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, was identified that evaluated IFS for treating dyspepsia.(11) The study 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 at 4 weeks, 5 of 25 patients (20%) in the treatment group and 6 of 25 (24%) patients in the placebo group reported epigastric discomfort.
IFS has been tested for a variety of gastrointestinal (GI) conditions, with a small number of trials completed for each condition. The results of these trials are mixed, with some reporting benefit and others reporting no benefit. This body of evidence is inconclusive to determine 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.(12) Forty-two inpatient stroke patients with plantarflexor spasticity were randomized to a single 60-minute session with IFS or a placebo IFS treatment following 30 minutes of standard rehabilitation. In the placebo treatment, electrodes were attached but current was 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 the aforementioned 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.
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.
Summary of Evidence
There is insufficient evidence from well-designed trials that interferential current stimulation (IFS), a type of electrical stimulation, improves health outcomes (eg, pain, range of motion) for patients diagnosed with painful musculoskeletal conditions. The limited amount of evidence from a few small trials comparing IFS alone to a placebo or sham intervention for treating does not consistently show benefit. Some trials do not control for potential placebo effects, others do not adequately evaluate the incremental effects of IFS beyond that of a cointervention and/or do not adequately evaluate the equivalence of IFS and an alternative intervention. There is also insufficient evidence that IFS improves health outcomes for patients with other conditions, such as dyspepsia, irritable bowel syndrome, and constipation. Therefore, interferential stimulation is considered investigational.
Practice Guidelines and Position Statements
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 stimulation for the treatment of low back pain.(13)
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.(14)
Low back disorders: The guideline stated that the evidence on IFS is insufficient and the intervention is not recommended. The exception is that it may be considered as an option on a limited basis for acute low back pain with or without radicular pain.(15)
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.(16)
U.S. Preventive Services Task Force Recommendations
Medicare National Coverage
There is no national coverage determination (NCD). In the absence of an NCD, coverage decisions are left to the discretion of local Medicare carriers.
- 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
- 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
- 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
- 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. Oct 3 2012. PMID 23035006
- 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
- 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
- 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. Apr 12 2014. PMID 24728028
- 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
- 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
- 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
- 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
- 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
- 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
- American College of Occupational and Environmental Medicine (ACOEM). Shoulder Disorders. www.guideline.gov. Accessed October 22, 2014.
- American College of Occupational and Environmental Medicine (ACOEM). Low Back Disorders. www.guideline.gov. Accessed October 22, 2014.
- American College of Occupational and Environmental Medicine (ACOEM). Knee Disorders. www.guideline.gov. Accessed October 22, 2014.
|CPT||64550||Application of surface (transcutaneous) neurostimulator|
|97014||Application of a modality to 1 or more areas; electrical stimulation (unattended)|
|97032||Application of modality to one or more areas; electrical stimulation (manual), each 15 minutes (attended)|
|ICD-9-CM diagnosis||Investigational for all relevant diagnoses|
|HCPCS||G0283||Electrical stimulation (unattended), to 1 or more areas for indication(s) other than wound care, as part of a therapy plan of care|
|E1399||Durable medical equipment, miscellaneous|
|S8130||Interferential current stimulator, 2 channel|
|S8131||Interferential current stimulator, 4 channel|
|ICD-10-CM (effective 10/1/15)||Investigational for all relevant diagnoses|
|G56.40-G56.42||Causalgia of upper limb code range|
|G57.70-G57.72||Causalgia of lower limb code range|
|G89.0-G89.4||Pain, not elsewhere classified code range|
|G90.50-G90.59||Complex regional pain syndrome I code range|
|M25.50-M25.579||Pain in joint code range|
|M54.00-M54.9||Dorsalgia code range|
|M79.60-M79.676||Pain in limb, hand, foot, fingers and toes code range|
|ICD-10-PCS (effective 10/1/15)||ICD-10-PCS codes are only used for inpatient services. There is no specific ICD-10-PCS code for the initiation of this therapy.|
Electrical Stimulation, Interferential
|07/17/03||Add policy to Durable Medical Equipment section||New policy|
|11/9/04||Replace policy||Policy updated with literature review; policy statement unchanged|
|08/17/05||Replace policy||Policy updated with literature review; policy statement unchanged|
|12/14/05||Replace policy||Policy updated with literature review: policy statement unchanged.|
|12/12/06||Replace policy||Policy updated with literature review: policy statement unchanged.|
|04/09/08||Replace policy||Policy updated with literature review; references 7-9 added; policy statement unchanged|
|10/06/09||Replace policy||Policy updated with literature search, no references added, policy rationale edited extensively. The term, “for treatment of pain,” was added to the policy title and policy statement, intent of policy statement unchanged.|
|11/11/10||Replace policy||Policy updated with literature search; references 1 and 9 added; other references re-numbered or removed. Policy statement unchanged.|
|03/10/11||Replace policy – correction only||Corrected number of pooled mean difference in Fuentes and colleagues’ systematic review (from 1.17 to -1.17) in 2nd paragraph of Rationale section.|
|12/08/11||Replace policy||Policy updated with literature search; references 6 and 7 added; other references re-numbered or removed. Policy statement unchanged|
|12/13/12||Replace Policy||Policy updated with literature search. References 4, 7-10 added; other references renumbered or removed. “For treatment of pain” removed from policy statement. Title changed to “Interferential Current Stimulation.”|
|12/12/13||Replace policy||Policy updated with literature search through October 24, 2013. References 4 and 12 added; other references renumbered or removed. No change in policy statement.|
|12/11/14||Replace policy||Policy updated with literature review through November 10, 2014. References 7, 12, and 14-16 added. No change in policy statement.|