Am I Candidate for TENS Therapy?

Transcutaneous electrical nerve stimulation is inexpensive, easy-to-use, and provides short-term pain relief for many.

 

TENS units are everywhere—drug stores, discount chains, the internet. People use these portable devices to find pain relief for conditions from arthritis to traumatic injury.

Formally known as transcutaneous electrical nerve stimulation, TENS is a popular option for managing pain as front-line therapy, as an addition to other treatments, or when other approaches fail, says Tiziano Marovino, DPT, MPH, clinical research physical therapist and practitioner at Chronic Pain Solutions in Ypsilanti, Michigan, and an editorial advisor to PPM.

“When TENS is applied to a well-selected patient, the pain relief can be very significant and can exceed 75%,” he explains.

Before running out and purchasing a TENS device, however, consider the advice of Dr. Marovino, who regularly conducts new product evaluations and writes technical reports for durable medical equipment companies.

A sample TENS unit package. (Image courtesy of Dr. Marovino)

What Is TENS?

Transcutaneous electrical nerve stimulation may sound scary, but electrical stimulation for pain is not new. Way back in 153 AD, the Roman physician Scribonius Largus advised patients to stand on torpedo fish, aka the electric ray, to relieve gout pain. The history of TENS use in the United States goes back 60 years.

TENS therapy helps to relieve pain using high-voltage, low amperage electrical current. It is essentially “a pain-masking device,” explains Dr. Marovino. “It doesn’t do much for the cause of the problem, but it can provide short-term relief similar to pain medications but without the myriad adverse effects.”

Research on the effectiveness of TENS varies, but studies using data from functional MRI (which measures metabolic function instead of a traditional MRI, which measures anatomical structure) have revealed that TENS can decrease pain-related activation in the brains of individuals with carpal tunnel syndrome and other types of chronic pain.

Other studies of TENS have found the evidence of its effectiveness “conflicting” or of “low quality.”

Dr. Marovino’s response to critics of TENS is, “My feeling is that people don’t use TENS based on the scientific status of the technology—they use it because they tried it and it worked for them.”

The TENS Device

A typical TENS unit has four components: a hand-held current generator, also called the box; four lead wires; four electrodes; and a 9-volt battery. The lead wires run from the box to the electrodes, which are placed on the skin over the painful area with soft adhesive pads.

With the box, a person can change the frequency, pulse width, and intensity of the electrical current. The three therapy modes on conventional units are burst, continuous, and intermittent. Pricier models might feature modes such as kneading, cupping, and shiatsu. TENS treatments can last from 30 to 60 minutes per session, with multiple sessions throughout the day, says Dr. Marovino.

The low cost and portability of TENS devices make them ideal for home use, says Dr. Marovino.

TENS should not be confused with spinal cord stimulation (SCS), which uses an implantable device that is inserted onto the spinal cord by an interventional pain physician.

Get Professional Advice before Trying or Buying

Even though TENS units can be purchased without a prescription, Dr. Marovino recommends not buying or using one without professional advice.

Always see a clinician first about your pain and before you start using TENS. “A patient evaluation should always precede TENS dispensing to ensure that someone is not simply masking pain from systemic pathology that needs to be addressed differently [such as a tumor],” explains Dr. Marovino. “People who decide on their own to purchase these devices without having been screened for other diseases run the risk of doing more harm than good.”

Take TENS for a trial run at the clinic to see if it works for you. “A brief TENS trial can remove any doubt as to whether a device will work for a particular patient or not,” says Dr. Marovino.

TENS users should be mindful of the risk of electrical shock, burns, post-treatment soreness if intensity is too high, and, less commonly, misapplication of the device resulting in tissue damage – all the more reason to consult a physical therapist or other provider. “These risks can be mitigated by getting an in-service performed by a licensed health professional familiar with the unit,” says Dr. Marovino.

What Kind of Pain Does TENS Treat?

“TENS can be used for acute post-surgical pain, chronic intractable pain, and virtually anything in between,” says Dr. Marovino. “It has been used for myofascial, neuropathic, mechanical, and centralized-type pain with the response being unique to that person.” More simply put, TENS treatments commonly target joint and nerve pain in the back, neck, elbow, wrist, and ankle.7

“We prefer to use TENS on the larger body areas such as a spine, arms, or legs,” says Dr. Marovino. Patients who are emaciated or frail may not respond as well to TENS therapy, he added.

More cautions: Do not use TENS on the head, over the face, throat, heart, genitals, broken skin, or if you are pregnant, have cancer, use a pacemaker/defibrillator, or have an infection such as osteomyelitis. Do not use TENS while driving, bathing, or sleeping.

A TENS unit in application. Image courtesy of Dr. Marovino.

Will TENS Help Your Pain?

Many factors influence whether you’ll feel pain relief with TENS. Dr. Marovino notes that a person’s age, type of pain condition and its severity, other medical conditions one might have, neurological integrity, and a host of other variables can affect how a person experiences and responds to pain.

For instance, some people can develop a tolerance to TENS if they use the same stimulation pattern repeatedly over time, meaning they will have to increase the stimulus intensity to achieve the same pain relief. To overcome this, they can vary the stimulation pattern by changing frequencies and pulse durations, says Dr. Marovino.

Which TENS Device Is for You?

A Google search of “TENS” returns 197 million results. Options abound, including digital versus analog, push-button versus dial controls, high-contrast screens, timers with auto-shut-off, extra electrode pads, and wide varieties in treatment modes and intensity levels.

Rather than wading through the internet, Dr. Marovino suggests selecting a unit alongside your physical therapist or other licensed practitioner. Look for a unit that is analog (non-digital) and is made by a reputable company. TENS units can cost up to several thousand dollars, but you can find a good unit for much, much less. At his clinic, he says, “We choose devices clinically that are in the $75 to $100 range, finding they provide the best of pricing and performance including longevity.”

Updated on: 06/04/20
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Am I a Candidate for Spinal Cord Stimulation?
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