In January 2007, Encore Medical Corporation, an orthopedic medical device company with offices in St. Paul, began offering the Empi Select transcutaneous electrical nerve simulation device for chronic pain due to arthritis. It’s portable and can be used at home, and has preset treatment programs making it easy to use. The Empi Select lessens chronic and acute pain by delivering electrical pulses through the skin to the nerves. Encore says this type of pain relief doesn’t come with the side effects that can accompany oral medication or topical ointments.

There are two theories as to how this type of electrical stimulation works. One is that there are many “gates” on a nerve between its ending and the spinal cord and brain that control how many messages get through to the brain. For instance, one nerve can tell the brain it either feels pain or doesn’t, and the gates regulate this information so that too much information doesn’t get through to the brain too fast. This first theory says that transcutaneous electrical nerve stimulation allows the gates to send only non-pain messages to the brain. The other theory is that this type of stimulation helps the body to produce endorphins, or natural pain killers, which block pain receptors in the nervous system.

To use the device, a patient puts electrodes directly onto his or her skin in the area where pain control is needed, turns the device on, and chooses one of nine program options, such as those for the knee, shoulder, and back. The intensity can be set to different levels, and programs can be customized. Empi Select is being prescribed by local doctors for patient use at home.