Background

Interferential current stimulation (IFS) is a type of electrical stimulation that has been investigated as a technique to reduce pain, improve function and range of motion, and treat gastrointestinal disorders.

IFS uses paired electrodes of 2 independent circuits carrying high-frequency 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 nerve stimulation. There are no standardized protocols for the use of IFS; IFS may vary by the frequency of stimulation, the pulse duration, treatment time, and electrode-placement technique.

Regulatory Status

A number of IFS devices have been cleared for marketing by the U.S. Food and Drug Administration through the 510(k) process, including the Medstar™ 100 (MedNet Services) and the RS-4i® (RS Medical). IFS may be included in multimodal electrotherapy devices such as transcutaneous electrical nerve stimulation and functional electrostimulation.

Related Policies

• Electrotherapies in Pain Management (Policy #025 in the Treatment Section)
• Biofeedback (Policy #060 in the Treatment Section)

For members enrolled in Medicaid and NJ FamilyCare plans, Horizon BCBSNJ applies the above medical policy.

FIDE SNP:

For members enrolled in a Fully Integrated Dual Eligible Special Needs Plan (FIDE-SNP): (1) to the extent the service is covered under the Medicare portion of the member’s benefit package, the above Medicare Coverage statement applies; and (2) to the extent the service is not covered under the Medicare portion of the member’s benefit package, the above Medicaid Coverage statement applies.

[RATIONALE: This policy was created in 2015 and has been updated regularly with searches of the PubMed database. The most recent literature update was performed through April 17, 2020.

Evidence reviews assess the clinical evidence to determine whether the use of technology improves the net health outcome. Broadly defined, health outcomes are the length of life, quality of life, and ability to function-including benefits and harms. Every clinical condition has specific outcomes that are important to patients andmanaging the course of that condition. Validated outcome measures are necessary to ascertain whether a condition improves or worsens; and whether the magnitude of that change is clinically significant. The net health outcome is a balance of benefits and harms.

To assess whether the evidence is sufficient to draw conclusions about the net health outcome of technology, 2 domains are examined: the relevance, and quality and credibility. To be relevant, studies must represent one or more intended clinical use of the technology in the intended population and compare an effective and appropriate alternative at a comparable intensity. For some conditions, the alternative will be supportive care or surveillance. The quality and credibility of the evidence depend on study design and conduct, minimizing bias and confounding that can generate incorrect findings. The randomized controlled trial (RCT) is preferred to assess efficacy; however, in some circumstances, nonrandomized studies may be adequate. RCTs are rarely large enough or long enough to capture less common adverse events and long-term effects. Other types of studies can be used for these purposes and to assess generalizability to broader clinical populations and settings of clinical practice.

Musculoskeletal Conditions

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.

Clinical Context and Therapy Purpose

The purpose of using interferential current stimulation (IFS) in patients who have musculoskeletal conditions is to provide a treatment option that is an alternative to or an improvement on existing therapies.

The question addressed in this policy is: Does the use of IFS improve health outcomes for those with musculoskeletal conditions?

The following PICO was used to select literature to inform this policy.

Patients

The relevant population of interest is individuals with musculoskeletal conditions.

Interventions

The therapy being considered is IFS.

Comparators

The following therapies are currently being used: physical therapy, medication, and other types of electrical stimulation.

Outcomes

The specific outcomes of interest are pain control, increased functional capacity, and improved quality of life. IFS would be used as adjunctive treatment with observed effects to be expected within 6 months.

Review of Evidence
Systematic Reviews

A network meta-analysis by Zeng et al (2015) identified 27 RCTs on 5 types of electrical stimulation therapies used to treat pain in patients with knee osteoarthritis (OA).^1, Reviewers found that IFS was significantly more effective than control interventions for pain relief (standardized mean difference, 2.06; 95% credible interval, 1.10 to 3.19) and pain intensity (standard mean difference, -0.92; 95% credible interval, -1.72 to -0.05). The validity of these conclusions is uncertain due to the limitations of the network meta-analysis, which used indirect comparisons to make conclusions. A further limitation is that the findings of placebo-controlled studies were not reported separately; rather, they were pooled in the analysis of usual care comparators. A more recent systematic review and meta-analysis by Ferreira et al (2019) evaluated non-surgical and non-pharmacological interventions for knee osteoarthritis.^2, However, as it only evaluated 1 RCT on IFS, the RCT by Gundog et al discussed below (2012), it did not add new information to the network meta-analysis by Zeng et al (2015).

The National Institute of Health and Care Excellence (NICE) (2016) published an evidence review on non-invasive treatments for low back pain.^3, This review included 4 non-US RCTs published between 1999 and 2014 that compared IFC to sham (n=117), usual care (n=60), or manual therapies (n=387). NICE reported that compared to sham or traction, IFC did not demonstrate a clinically important improvement in pain. No studies evaluated impact on quality of life, nor did any studies include people with sciatica. NICE concluded that evidence does not support IFC for low back pain.

Fuentes et al (2010) published a systematic review and meta-analysis of RCTs evaluating the effectiveness of IFS for treating musculoskeletal pain.^4, Twenty RCTs met the following inclusion criteria: adults diagnosed with a painful musculoskeletal condition (eg, knee, back, joint, shoulder, or OA pain); compared IFS alone or as a co-intervention with placebo, no treatment, or an alternative intervention; and assessed pain using a numeric rating scale. Fourteen of the trials reported data that could be pooled. 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 with 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). Also, a pooled analysis of 2 studies comparing IFS alone with 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 with a placebo, there was a nonsignificant finding in pain intensity at discharge (MD=1.60; 95% CI, -0.13 to 3.34; p=0.07). The meta-analysis found IFS plus another intervention to be superior to a control group (eg, 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.

Randomized Controlled Trials

Two placebo-controlled randomized trials were included in the Fuentes et al (2010) meta-analysis, one of which (Defrin et al [2005]^5,) was also included in the Zeng et al (2015) meta-analysis. The Defrin et al (2005) trial included 62 patients with OA knee pain.^5, Patients were randomized to 1 of 6 groups (4 active treatment groups and 2 control groups, sham and nontreated). Acute pre- vs posttreatment reductions in pain were found for all active groups but neither control group. Stimulation resulted in a modest pretreatment elevation of pain threshold over this 4 week trial. Taylor et al (1987) randomized 40 patients with a temporomandibular joint syndrome or myofascial pain syndrome to active or placebo IFS.^6, Principal outcomes were pain assessed by a questionnaire and range of motion. There were no statistically significant differences in the outcomes between groups.

Two other RCTs, both published in 2012, were included in the Zeng et al (2015) meta-analysis. One found significantly better outcomes with IFS vs placebo while the other did not find significant differences between active and sham interventions. Atamaz et al (2012) compared IFS, transcutaneous electrical nerve stimulation, shortwave diathermy, and sham interventions for treating knee OA.^7, 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 knee pain as assessed on a visual analog scale (VAS; range, 0-100). Other outcomes included range of motion, time to walk 15 meters, paracetamol intake, the Nottingham Health Profile score, and the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) score. At the 1-, 3-, and 6-month follow-ups, there were no statistically significant differences across the 6 groups in VAS pain scores, Nottingham Health Profile pain scores, or WOMAC pain scores. Moreover, WOMAC function scores, time to walk 15 meters, and Nottingham Health Profile physical mobility scores did not differ significantly among groups at any follow-up assessments. At the 1 month follow-up, paracetamol intake was significantly lower in the IFS group than in the transcutaneous electrical nerve stimulation group.

Gundog et al (2012) randomized 60 patients with knee OA to 1 of 4 groups: 3 IFS groups at frequencies of 40 Hz, 100 Hz, and 180 Hz, and 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 vs active treatment groups). Secondary outcomes (eg, VAS score) also showed significantly higher benefit in the active treatment groups compared with the sham IFS group. The number of patients assigned to each group and patient follow-up rates was not reported.

To evaluate IFS after arthroscopic knee surgery, Kadi et al (2019) conducted a double blind, placebo controlled RCT in 98 individuals.^9, IFS or sham treatment (pads applied with no current) was delivered for 30 minutes, twice a day for 5 days postoperatively. Although IFS significantly reduced the amount of paracetamol used by day 5, no significant difference was found between the groups with respect to pain, range of motion, or edema at days 0 through 30.

In addition to the placebo-controlled trials, several RCTs have compared IFS with another active intervention or with usual care.^{10,11,12,13,14,15,13,} 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 randomized trials of IFS for treating musculoskeletal pain and impaired function have mostly found that IFS 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.

Gastrointestinal Disorders
Clinical Context and Therapy Purpose

The purpose of using IFS in patients who have gastrointestinal disorders (eg, constipation, irritable bowel syndrome, and dyspepsia) is to provide a treatment option that is an alternative to or an improvement on existing therapies.

The question addressed in this policy is: Does the use of IFS improve health outcomes for those with gastrointestinal disorders?

The following PICO was used to select literature to inform this policy.

Patients

The relevant population of interest is individuals with a gastrointestinal disorder such as constipation, irritable bowel syndrome, or dyspepsia.

Interventions

The therapy being considered is IFS.

Comparators

The following therapies are currently being used: dietary changes, medication, and other types of electrical stimulation.

Outcomes

The specific outcomes of interest are pain control, increased functional capacity, and improved quality of life. Safety and efficacy of IFS would be evaluated at 1 month following a 4 week treatment.

Constipation
Review of Evidence

No large RCTs have adequately evaluated the comparative effects of using IFS to treat constipation versus the comparators of interest. Ideally, an RCT would compare IFS to another treatment of interest such as dietary changes, medication, or different types of electrical stimulation and include an IFS sham-control group to rule out a potential placebo effect.

Several sham-controlled 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 IFS.

A systematic review of neuromodulation approaches for constipation and fecal incontinence in children by Iacona et al (2019) included 2 of the RCTs, as well as 1 prospective study, and 2 pilot studies (N=126).^16, Study follow-up times ranged from 1 to 6 months. Systematic review authors reported that all of the studies reported an improvement in symptoms reported including defecation frequency, soiling episodes, and abdominal pain. This systematic review included the RCT by Kajbafzadeh et al (2012) in Iran that randomized 30 children with intractable constipation to IFS or sham stimulation.^17, Children ranged in age from 3 to 12 years old and had failed 6 months of conventional therapy (eg, dietary changes, laxatives). Patients received 15, IFS sessions (20 minutes long), 3 times a week for 5 weeks. Over 6 months, the mean frequency of defecation increased from 2.5 times a week to 4.7 times a week in the treatment group and from 2.8 times a week to 2.9 times a 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. Overall, however, the systematic review authors concluded additional evidence including longer length of follow-up is needed to consider neuromodulation as an established therapy for the management of constipation and fecal incontinence.

Additionally, another RCT, published by Clarke et al (2009) from Australia, and not included in the systematic review by Iacona et al (2019), did not find a benefit of IFS.^18, Thirty-three children with slow transit time constipation (mean age, 12 years) were randomized to IFS or sham treatment. They received 12, 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. The authors only reported within-group changes; they did not compare the treatment and control groups. There was no statistically significant change in quality of life, as perceived by the parent group. The mean parent-reported quality of life 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 quality of life, as perceived by the child after sham treatment. The Pediatric Quality of Life Inventory score, as perceived by the child, did increase significantly in the active treatment group (mean, 72.9 pretreatment vs 81.1 posttreatment, p=0.005).

In adults, 1 small, single-blind, sham-controlled RCT conducted in Australia was identified.^19, Thirty-three women (mean age, 45 years) with functional constipation were randomized to IFS (N=17) or sham treatment (N=16). The IFS was self-delivered by the participants in their homes for 1 hour per day for 6 weeks. The participants were trained by an unblinded study coordinator in the placement of the 4 electrodes as either crossed for active IFS or uncrossed for sham IFS. The primary outcome was the number of patients with ≥3 spontaneous bowel movements per week. Although active IFS significantly increase the primary outcome (53% versus 12%; P=.02), there were no between-group differences on numerous other secondary outcomes, such as quality of life and the more clinically meaningful and guideline-recommended outcome of spontaneous complete bowel movement.

Irritable Bowel Disease
Review of Evidence

An RCT by Coban et al (2012) randomized 67 adults with irritable bowel syndrome to active or placebo IFS.^20, Patients with functional dyspepsia were excluded. Patients received 4, 15-minute IFS sessions over 4 weeks. Fifty-eight (87%) of 67 patients completed the trial. One month after treatment, primary outcome measures did not differ significantly between treatment and control groups. For example, for abdominal discomfort, the response rate (ie, >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, 72% of the treatment group and 69% of the control group reported improvement in abdominal discomfort.

Dyspepsia
Review of Evidence

One RCT, by Koklu et al (2010) in Turkey, has evaluated IFS for treating dyspepsia.^21, The trial randomized adults to active IFS (n=25) or sham treatment (n=25); patients were unaware of their treatment allocation. Patients received 12 treatment sessions over 4 weeks; each session lasted 15 minutes. Forty-four (88%) of 50 randomized patients completed the therapy session and follow-up questionnaires at 2 and 4 weeks. The trialists did not specify primary outcome variables; rather, they measured the frequency of 10 gastrointestinal symptoms. In an intention-to-treat 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 (64%) of 25 patients in each group reported experiencing heartburn. At 4 weeks, 9 (36%) patients in the treatment group and 13 (52%) patients in the sham group reported heartburn (p=0.02). Among symptoms that did not differ between groups at follow-up, 24 (96%) of 25 patients in each group reported epigastric discomfort before treatment. In the intention-to-treat analysis, 5 (20%) of 25 patients in the treatment group and 6 (24%) of 25 patients in the placebo group reported epigastric discomfort.

Section Summary: Gastrointestinal Disorders

IFS has been tested as a treatment option for a variety of gastrointestinal conditions, with a small number of trials completed for each condition. Trial results were mixed, with some reporting benefit and others not. This body of evidence is inconclusive on whether IFS is an efficacious treatment for gastrointestinal conditions.

Poststroke Spasticity
Clinical Context and Therapy Purpose

The purpose of using IFS in patients who have poststroke spasticity is to provide a treatment option that is an alternative to or an improvement on existing therapies.

The question addressed in this policy is: Does the use of IFS improve health outcomes for those with poststroke spasticity?

The following PICO was used to select literature to inform this policy.

Patients

The relevant population of interest is individuals with poststroke spasticity.

Interventions

The therapy being considered is IFS.

Comparators

The following therapy is currently being used: standard stroke rehabilitation.

Outcomes

The specific outcomes of interest are improved function and quality of life. Effect of IFS would be assessed 1 hour after a single treatment.

Review of Evidence
Randomized Controlled Trials

A single-blind RCT evaluating IFS as a treatment of chronic stroke was published by Suh et al (2014).^22, 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; however, the 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. Also, gait speed was measured using a 10-meter walk test, and gait function was assessed with the Timed Up & 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 (standard deviation) difference in Modified Ashworth Scale score was 1.55 (0.76) in the IFS group and 0.40 (0.50) in the placebo group. A major limitation of the trial was that outcomes were only measured 1 hour after the intervention and no data were available on longer-term impacts of the intervention.

Additionally, an RCT comparing IFS (n=20) to electrical acupuncture (EAC) (n=20) in individuals with hemiplegic shoulder pain after stroke was published by Eslamian et al (2020).^23, The interventions were added to standard care and delivered twice a week for a total of 10 sessions. The primary outcome was reduction in pain intensity at 5-weeks compared to baseline as measured using a 10 cm Visual Analogue Scale (VASs). Results were mixed across outcomes. For example, rates of clinically significant improvement of at least 13 on the Shoulder Pain and Disability Index (SPADI) questionnaire were similar between groups (75% versus 65%). However, rate of clinically significant improvement in pain intensity (defined as 1.4 points on the VAS at 5-weeks) was lower in the IFS group (35.0% versus 70.0%). Additionally, this study has several limitations, including lack of sham control group, very small sample size, short follow-up interval.

Section Summary: Poststroke Spasticity

Data from small RCT's with very short follow-up provides insufficient evidence on the impact of IFS on health outcomes in patients with post-stroke spasticity.

Summary of Evidence

For individuals who have musculoskeletal conditions who receive 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 randomized trial(s) have found that IFS when used to treat musculoskeletal pain and impaired function(s), does not significantly improve outcomes; additionally, 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. The results of the trials 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 RCTs. Relevant outcomes are symptoms, functional outcomes, quality of life, and treatment-related morbidity. The RCTs had small sample sizes and very short follow-up (immediately posttreatment to 5 weeks). The evidence is insufficient to determine the effects of the technology on health outcomes.

SUPPLEMENTAL INFORMATION
Practice Guidelines and Position Statements
American College of Physicians and the American Pain Society

In 2009, the clinical practice guidelines from the American College of Physicians and the American Pain Society concluded that there was insufficient evidence to recommend interferential current stimulation (IFS) for the treatment of low back pain.^24, An update of these guidelines by the American College of Physicians (2017) confirmed the 2009 findings that there was insufficient evidence to determine the effectiveness of interferential current stimulation (IFS) for the treatment of low back pain.^25,

American College of Occupational and Environmental Medicine

The American College of Occupational and Environmental Medicine published several relevant guidelines. For shoulder disorders, guidelines found the evidence on IFS to be insufficient and, depending on the specific disorder, either did not recommend IFS or were neutral on whether to recommend it.^26, For low back disorders, guidelines found the evidence on IFS to be insufficient and did not recommend it. The sole exception was that IFS could be considered as an option on a limited basis for acute low back pain with or without radicular pain.^27,For knee disorders, guidelines recommended IFS for postoperative anterior cruciate ligament reconstruction, meniscectomy, and knee chondroplasty immediately postoperatively in the elderly.^28, This was a level C recommendation.

National Institute for Health and Care Excellence

In 2016, the National Institute for Health and Care Excellence had a guideline (NG59) on assessment and management of low back pain and sciatica in people aged 16 and over.^3, The guideline states “Do not offer interferential therapy for managing low back pain with or without sciatica”.

U.S. Preventive Services Task Force Recommendations

Not applicable.

Ongoing and Unpublished Clinical Trials

Some currently unpublished trials that might influence this policy are listed in Table 1.

Table 1. Summary of Key Trials

NCT No.	Trial Name	Planned Enrollment	Completion Date
Ongoing
NCT02381665	Efficacy of Interferential Therapy in Chronic Constipation (CON-COUR) (CON-COUR)	200	Mar 2019 (Status: unknown)

NCT: national clinical trial.
________________________________________________________________________________________

Horizon BCBSNJ Medical Policy Development Process:

This Horizon BCBSNJ Medical Policy (the “Medical Policy”) has been developed by Horizon BCBSNJ’s Medical Policy Committee (the “Committee”) consistent with generally accepted standards of medical practice, and reflects Horizon BCBSNJ’s view of the subject health care services, supplies or procedures, and in what circumstances they are deemed to be medically necessary or experimental/ investigational in nature. This Medical Policy also considers whether and to what degree the subject health care services, supplies or procedures are clinically appropriate, in terms of type, frequency, extent, site and duration and if they are considered effective for the illnesses, injuries or diseases discussed. Where relevant, this Medical Policy considers whether the subject health care services, supplies or procedures are being requested primarily for the convenience of the covered person or the health care provider. It may also consider whether the services, supplies or procedures are more costly than an alternative service or sequence of services, supplies or procedures that are at least as likely to produce equivalent therapeutic or diagnostic results as to the diagnosis or treatment of the relevant illness, injury or disease. In reaching its conclusion regarding what it considers to be the generally accepted standards of medical practice, the Committee reviews and considers the following: all credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, physician and health care provider specialty society recommendations, the views of physicians and health care providers practicing in relevant clinical areas (including, but not limited to, the prevailing opinion within the appropriate specialty) and any other relevant factor as determined by applicable State and Federal laws and regulations.

___________________________________________________________________________________________________________________________

Index:
Interferential Current Stimulation
Interferential Stimulation for the Treatment of Pain and Other Conditions
Interferential Stimulation
Interferential Current Stimulation
Medstar 100
RS-4i
RS 4i
IFS

References:
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. Ferreira RM, Torres RT, Duarte JA, et al. Non-Pharmacological and Non-Surgical Interventions for Knee Osteoarthritis: A Systematic Review and Meta-Analysis. Acta Reumatol Port. Jul 29 2019; 44(3): 173-217. PMID 31356585

3. National Institute for Health and Care Excellence (NICE). Low back pain and sciatica in over 16s: assessment and management [NG59]. 2016; https://www.nice.org.uk/guidance/ng59. Accessed April 21, 2020.

4. 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

5. 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

6. 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

7. 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

8. 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

9. Kadi MR, Hepguler S, Atamaz FC, et al. Is interferential current effective in the management of pain, range of motion, and edema following total knee arthroplasty surgery? A randomized double-blind controlled trial. Clin Rehabil. Jun 2019; 33(6): 1027-1034. PMID 30764635

10. 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

11. 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

12. 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

13. 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. Feb 2017;31(2):242-249. PMID 26975312

14. 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. Sep 2016;95(9):663-672. PMID 26945216

15. Albornoz-Cabello M, Perez-Marmol JM, Barrios Quinta CJ, et al. Effect of adding interferential current stimulation to exercise on outcomes in primary care patients with chronic neck pain: a randomized controlled trial. Clin Rehabil. Sep 2019; 33(9): 1458-1467. PMID 31007047

16. Iacona R, Ramage L, Malakounides G. Current State of Neuromodulation for Constipation and Fecal Incontinence in Children: A Systematic Review. Eur J Pediatr Surg. Dec 2019; 29(6): 495-503. PMID 30650450

17. 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

18. 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

19. Moore JS, Gibson PR, Burgell RE. Randomised clinical trial: transabdominal interferential electrical stimulation vs sham stimulation in women with functional constipation. Aliment Pharmacol Ther. Apr 2020; 51(8): 760-769. PMID 32128859

20. 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. Aug 2012;86(2):86-93. PMID 22846190

21. 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

22. 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

23. Eslamian F, Farhoudi M, Jahanjoo F, et al. Electrical interferential current stimulation versus electrical acupuncture in management of hemiplegic shoulder pain and disability following ischemic stroke-a randomized clinical trial. Arch Physiother. 2020; 10: 2. PMID 31938571

24. Chou R, Atlas SJ, Stanos SP, et al. Nonsurgical interventional therapies for low back pain: a review of the evidence for an American Pain Society clinical practice guideline. Spine (Phila Pa 1976). May 1 2009;34(10):1078-1093. PMID 19363456

25. Qaseem A, Wilt TJ, McLean RM, et al. Noninvasive Treatments for Acute, Subacute, and Chronic Low Back Pain: A Clinical Practice Guideline From the American College of Physicians. Ann Intern Med. Apr 04 2017; 166(7): 514-530. PMID 28192789

26. American College of Occupational and Environmental Medicine (ACOEM). Shoulder disorders. In: Hegmann KT, ed. Occupational medicine practice guidelines. Evaluation and management of common health problems and functional recovery in workers. 3rd ed. Elk Grove Village, IL: ACOEM; 2011:1-297.

27. American College of Occupational and Environmental Medicine (ACOEM). Low Back Disorders. In: Hegmann KT, ed. Occupational medicine practice guidelines: evaluation and management of common health problems and functional recovery in workers. Westminster, CO: Reed Group; 2016:1-844.

28. American College of Occupational and Environmental Medicine (ACOEM). Knee Disorders. In: Hegmann KT, ed. Occupational medicine practice guidelines. Evaluation and management of common health problems and functional recovery in workers. 3rd ed. Elk Grove Village, IL: ACOEM; 2011:1-503.

Codes:
(The list of codes is not intended to be all-inclusive and is included below for informational purposes only. Inclusion or exclusion of a procedure, diagnosis, drug or device code(s) does not constitute or imply authorization, certification, approval, offer of coverage or guarantee of payment.)

CPT*

S8130
S8131