IFC for Pain Management

IFC, or interferential current, is a type of electrical stimulation that uses two different channels at the same time. When setting it up, the electrodes for the respective channels should be set up in a crossing pattern so that the electrical currents cross. When two waves combine at the same point, they have a summative result. Setting each channel at a different frequency results in a varied summation at each time point and makes a beat frequency. This type of electrical stimulation is used for pain, edema, and muscle rehab depending on the beat frequency that is produced.

Articles in Favor of IFC:

Goats, G.C. article explained the basics of how IFC works while incorporating older studies that supported the effectiveness. Some of the studies were aimed at determining dosage; therefore, already assuming IFC works. Goats explained that interferential therapy is theoretically effective for stimulating muscle, increasing blood flow, and accelerating bone healing. Case studies and observational evidence support edema reduction, incontinence control, and pain reduction from IFC. Take into consideration that this article was published many years ago so new studies may be more pertinent to today. Nonetheless, this article drew upon numerous studies that specifically identified IFC as an effective method of therapy. It’s obvious that IFC has great potential as a therapeutic intervention but further research is needed to fully understand how it fits in the clinic.

Goats, G. C. (1990). Interferential current therapy. British journal of sports medicine, 24(2), 87-92. Retrieved from http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1478878&tool=pmcentrez&rendertype=abstract

The article by Jorge, Parada, Ferreira, and Tambeli analyzed the effect of interferential current therapy on inflammatory pain and edema in rats.  They used formalin injections, which evoked a local release of histamine and serotonin which activated nociceptors, and carrageenan injections, which produced a mechanical hyperalgesia.  Both injection types resulted in edema.  They rats were divided into groups, based on which injection they received and when the interferential current treatment was given, before or after.  Edema was monitored in separate groups.  For each group, there was one control group, which had the interferential current off, and one in which there were no electrodes at all. 

In the groups with the formalin injection, a significant effect was found only in the nociceptive behavior in the group receiving the interferential current for the hour after the injection.  In the groups with Carrageenan injections, the interferential current showed significant effects while on, but once discontinued, those effects disappeared.  There was not a significant change in the amount of edema with any of the groups.  Both formalin and carrageenan mimic the human inflammatory pain state brought on by traumatic pain.  This information would be most appropriate for pain relief post-surgical or after other trauma induced pain.

Jorge S, Parada C, Ferreira S, Tambeli C. Interferential therapy produces antinociception during application in various models of inflammatory pain. Physical Therapy [serial online]. June 2006;86(6):800-808. Available from: CINAHL Plus with Full Text, Ipswich, MA. Accessed February 27, 2012.

This article by Jarit, Mohr, Waller, and Glousman looked at the effect of IFC versus placebo effect on post-op knee surgery patients. The results looked at edema (girth measurement), range of motion, pain rating, and amount of pain medication taken. All subjects using IFC had significantly less pain than the placebo group. In general, the IFC group also took less pain medication, had greater range of motion and had less edema. The theory behind the greater ROM is that the patients that had IFC had less pain and were therefore able to tolerate more physical therapy. This article shows that IFC is a significantly effective way to decrease the amount of pain a patient is experiencing. However, there were some limitations to this study and more research needs to be done to have a greater picture of the benefits of IFC.

Jarit, G.J., Mohr, K.J., Waller, G., Glousman, R.E. The Effects of Home Interferential Therapy on Post-Operative Pain, Edema, and Range of Motion of the Knee. Clinical Journal of Sports Medicine. Jan 2003: 13(1): 16-20.

Articles Against IFC:

IFC is widely used in clinical practice to treat pain and there is a great deal of anecdotal support for its efficacy.  Unfortunately, there aren’t any high quality studies with sound methodological design that have substantiated its use. This can partly be attributed to the difficulty in adhering to strict methodological protocols (such as blinding subjects and therapists) when using therapeutic interventions like IFC.  But, more importantly, the absence of such high quality studies is more readily attributable to the lack of understanding concerning IFC’s mechanism of action and the attendant lack of standardization with regard to its application – such as electrode placement, stimulation frequency and intensity, or length of treatment time.  Beatti et al began a systematic review in 2008 of RCTs conducted since 1980 which had examined the efficacy of IFC. Of the 59 studies they found, only nine met their inclusion criteria. The studies used the outcome measures of pain intensity, pain threshold, and ROM, but, unfortunately, were of average methodological quality, and had findings that were either contradictory, inconclusive, or unpersuasive.  Beattie et al concluded that IFC may have an effect in reducing pain, but more rigorous, high quality research is needed to substantiate its efficacy.

Beatti, A.  et al. (2010). The analgesic effect of interferential therapy on clinical and experimentally induced pain. Physical Therapy Reviews, 15(4), 243-252.

This systematic review included randomized controlled trials that aimed to determine IFC’s effectiveness in treating musculoskeletal pain. The results were inconclusive, indicating that IFC alone was not shown to have significantly better results than other therapies. Keep in mind that the studies that used IFC as the ONLY intervention were very small. IFC as an adjunct to other interventions was found to be more effective for reducing pain than the control or placebo treatments. Optimal dosage for IFC is not clear. The results also imply that there are potential long-term benefits from IFC like in chronic conditions; currently IFC is mostly used for short-term pain. Heterogenity in the population was the main limit to this meta-analysis. Overall the evidence is weak to proclaim that IFC is truly effective.

Fuentes, J. P., Armijo Olivo, S., Magee, D. J., & Gross, D. P. (2010). Effectiveness of interferential current therapy in the management of musculoskeletal pain: a systematic review and meta-analysis. Physical therapy, 90(9), 1219-38. doi:10.2522/ptj.20090335

Furlan reviewed 154 eligible studies relating to interferential current, either independently or as a cointervention, for subjects clinically diagnosed with a painful musculoskeletal condition.  Twenty studies were included in a qualitative synthesis and fourteen studies were included in a meta-analysis.  A lack of consensus was found within the articles.  Some of the articles indicated that interferential current was not significantly different from the placebo or from a cointervention of interferential current and manual therapy.  There was also conflict between studies over the same condition, some showing a significance, others not.  The meta-analysis results indicated that interferential current may be beneficial for pain management when combined with other therapies, however independently it did not show a significant improvement.

Furlan, A. D. (2011). Evidence for Interferential Current to Treat Musculoskeletal Pain Remains Weak. Clinical Journal of Sport Medicine, 21(3), 278-279. Retrieved February 27, 2012, from http://ovidsp.tx.ovid.com.proxy.kumc.edu:2048/sp-3.5.1a/ovidweb.cgi?QS2=434f4e1a73d37e8c6a

Kylie Palermo, Rick Hill, Kate Wiens, Sarah Jarvis