FDA Clears New Prescription-Only TENS Device

By Pat Anson

Transcutaneous electrical nerve stimulation – more commonly known as TENS – uses mild electric currents to temporarily relieve pain in sore muscles and tissues. Some TENS units are elaborate wearable devices that cost hundreds of dollars, while others are simple gadgets that can be purchased online or over-the-counter for about $30.

Due to lingering questions about their effectiveness, many health insurers don’t cover TENS devices, while others make patients jump through hoops to get reimbursed for them.

Medical device maker Zynex Medical is hoping to bridge the gap in insurance coverage with a new TENS device called TensWave, which is only available by prescription. The company says the FDA has “cleared” TensWave for marketing, allowing sales to begin immediately.

"The introduction of TensWave aligns perfectly with our commitment to providing comprehensive pain management solutions," Thomas Sandgaard, CEO of Zynex, said in a press release.

"We recognized a gap in the market for a high-quality TENS device that meets the specific criteria for insurance reimbursement, and TensWave is our answer to that demand. It complements our flagship multi-modality device, the NexWave, where Interferential current is the main modality and driver of obtaining prescriptions. This device broadens our product portfolio and enhances our support to patients."

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Unlike NexWave, which has three different electrical stimulation modalities, TensWave only uses TENS technology, which Zynex believes will make it easier to get insurance coverage. The company currently has no estimate of TensWave’s cost if a patient has to buy it out-of-pocket.   

In its press release, Zynex said TensWave “has been clinically proven to reduce chronic and acute pain,” which is a bit of an exaggeration, because the device did not go through the FDA’s lengthy review and approval process. However, because TensWave has “substantial equivalence” to other TENS units already on the market, it was cleared for sale without ever undergoing a clinical trial to prove its safety and efficacy. This is a common practice allowed by the FDA when new medical devices are introduced.

The World Health Organization takes a dim view of TENS, saying the evidence of its effectiveness in relieving chronic lower back pain is “very low” due to a limited number of clinical trials. In some trials, TENS worked no better than a placebo.

The UK’s National Health Service (NHS) has a similar view of TENS, saying there is not enough good-quality evidence to recommend its use as a reliable method of pain relief.

“Healthcare professionals have reported that it seems to help some people, although how well it works depends on the individual and the condition being treated,” the NHS states. “TENS is not a cure for pain and often only provides short-term relief while the TENS machine is being used.”

Electromedical Treatments for Arachnoiditis

By Dr. Forest Tennant, PNN Columnist  

Adhesive Arachnoiditis (AA) is an inflammatory, nerve root entrapment disease in which cauda equina nerve roots are glued by adhesions to the arachnoid-dural covering of the spinal canal. An inflamed tumor-like mass is formed inside the spinal canal that blocks spinal fluid flow, allows seepage of fluid into tissue outside the spinal canal and shuts off electrical impulses that activate the legs, feet, bladder, intestine and sex organs. Autoimmunity is produced and/or magnified by AA. 

We highly recommend a three-component protocol for AA to reduce inflammation and autoimmunity, regenerate damaged tissue and to provide pain control. Recent advances in electromedical therapies can help achieve these three goals. 

There are two basic types of electromedical devices available for AA treatment: electric current therapy (EC) and electromagnetic therapy (EM). 

Electric Current Therapy 

Almost everyone is familiar with “TENS” units, which stands for “transcutaneous electrical nerve stimulation.” These devices were the first electromedical therapies to relieve pain and promote healing.

TENS units deliver a single electric current into tissues to produce an anesthetic, pain relieving effect.  

Today, more advanced EC devices administer micro-currents and/or a combination of multiple currents with different frequencies. 

Electromagnetic Therapy 

There is a form of energy that is half electricity and half magnetism, which can be divided into wave lengths. The very shortest wave of electromagnetic energy is “atomic” and the longest is “radio.” The shortest wave used in medicine is “laser.” Other electromagnetic energy waves used for medical purposes include infrared, light and microwave. 

EC and EM devices, when placed over the lower back, deliver electric current or electromagnetic energy to the lumbar-sacral spinal canal and the spine’s surrounding tissue.

Modern devices use intermittent pulsation of electric currents or electromagnetic energy to penetrate the skin and subcutaneous tissue to reach the AA site, which is usually about 2-3 inches below the skin.  

Some devices use the label PEMF, which stands for “pulsed electromagnetic frequency.” We believe that the newer EC and EM devices can deliver electric currents or electromagnetic energy that, when pulsed, penetrate deep enough to reach the AA disease site. 

Although not totally curative, these devices usually bring about pain reduction in the 20 to 30% range. Within an individual’s financial capability, we recommend that an EC and/or EM device be used 2 to 3 times a week (not daily). EC and EM therapy are not substitutes for a medical protocol. 

EM and EC devices often produce some initial healing, but later seem to stop working. In this situation the device may have done its maximal healing. The devices can still be used periodically to prevent relapses and treat flares. 

Forest Tennant, MD, DrPH, is retired from clinical practice but continues his research on the treatment of intractable pain and arachnoiditis. This column is adapted from a bulletin recently issued by the Arachnoiditis Research and Education Project. Readers interested in subscribing to the bulletins should click here.

Dr. Tennant’s new book, "Clinical Diagnosis and Treatment of Adhesive Arachnoiditis” is available on Amazon. 

The Tennant Foundation gives financial support to Pain News Network and sponsors PNN’s Patient Resources section.