Interferential therapy (IFT) is a popular form of electrical stimulation treatment used to treat low back pain. The unit has four pads (electrodes), which are placed on the skin in the form of a square. The current from each pad crosses through the body’s tissues in a path toward the opposite pad. In this way, the current forms an “X” between the corners of the four pads. The current collides in the center of the X. The place where they collide is called the interference point.
IFT is believed to help relieve both acute and chronic low back pain, although there is little evidence to support its use. There simply hasn’t been much research on the effectiveness of IFT. Still, this type of therapy is used in many parts of the world. The authors suggest this may be because therapists believe it works, and because it is easy to set up and use.
The authors designed this study as a first step toward a larger study comparing IFT to other treatments for low back pain. This particular study was used to see if pad placement made a difference. Currently, there are no guidelines on how to apply treatments. Individual therapists use different set-ups for IFT, including different placement of the electrodes. This study helped zero in on the best place to put the electrodes. It compared two different choices. The “spinal nerve root” technique is done by spacing the pads along the sides of the spinal column. More commonly, therapists position the electrodes using the “painful area” technique, which involves putting the pads over the spot where it hurts the most.
This study included 60 people who had back pain that had lasted for one to three months. Participants were placed into three groups. All groups answered surveys about their low back pain, disability related to the pain, and general health. One group got IFT with the spinal nerve root method for 30 minutes, two to three times a week. Another group received the same amounts of treatment with electrodes placed over the painful area. Both these groups also got a copy of The Back Book, an educational booklet with information on back problems that encourages early return to activity. The third group got the book only and just came in every other week for assessment.
The subjects answered the same surveys three months later. The authors found that all groups showed significant improvement over the course of the study. However, the group that got IFT treatments using the spinal nerve root technique showed significantly better scores on the questionnaires.
This study doesn’t answer any questions about how or why IFT helps relieve low back pain. It also doesn’t prove that IFT is more effective than other types of conservative treatments for low back pain. The results do show that pad placement probably makes a difference in how people with back pain are doing three months into treatment.
The authors will use this information to design a controlled trial of IFT, comparing the spinal nerve root technique with different forms of treatment for treating low back pain.