Chronic pain affects millions of people in the U.S., with back and leg pain being the most common forms. These types of pain are often relieved by conservative care (rest, chiropractic care, physical therapy), medications, and injection therapies. In cases where this chronic pain persists, other treatments may be necessary. One of the most cutting-edge treatment options is dorsal root ganglion stimulation.
Dorsal root ganglion stimulation
One of the most successful types of treatment for chronic pain is neurostimulation. These devices, such as spinal cord stimulators, relieve pain by delivering mild electrical pulses to the nerves. Those electrical pulses block out the pain signals, replacing the typical pain with a mild tingling sensation.
Traditional spinal cord stimulators deliver stimulation to dorsal column of the spinal cord, which runs directly along the center of the back through the spine. Depending on what point on the spinal cord receives the stimulation, different parts of the body are affected. This allows doctors to tailor the therapy to an individual’s painful area. One of the challenges encountered in neurostimulation therapy is that some patients have pain in places that are difficult to target. For example, when pain is at the very end of the limb (e.g., the bottom of the feet), it may require very strong stimulation of the rest of the limb (the leg) in order to relieve the pain in the target. If this stimulation is intense enough, it can be unpleasant.
One promising therapy for treating these difficult to cover pain patterns is dorsal root ganglion stimulation (DRG). The dorsal root ganglion is a part of the spine where nerves branch off from the dorsal column. These branches of nerves then further spread out throughout the body. By targeting dorsal root ganglion stimulation, it is possible to be much more selective in the area to be stimulated. For example, one can deliver stimulation to the feet without affecting the legs. It also requires much less stimulation to get relief by targeting the specific DRG that innervates the patient’s painful area.
St. Jude Medical recently concluded a study of their AxiumTM DRG stimulator for treating 152 patients with complex regional pain syndrome of the lower limbs. Complex regional pain syndrome is a condition often caused by an injury to an extremity that triggers a series of changes in the nervous system associated with that extremity, leading to changes in color, sensitivity to the touch and severe pain. Patients were randomly assigned to be implanted with either the current standard spinal cord stimulator or the AxiumTM DRG stimulator and were followed for 12 months.
The results of this study were presented at the North American Neuromodulation Society Meeting this last December. Consistent with previous research, the patients implanted with spinal cord stimulators received significant pain relief, with 72.2% of these patients receiving significant pain relief (at least 50%) without unpleasant stimulation at 3 months and 70% continuing to meet this goal after 12 months. However, those patients implanted the DRG stimulator received even greater success, with 93.3% experiencing significant pain relief without unpleasant stimulation at three months and 86% continuing to meet this goal at 12 months.
FDA approval for dorsal root ganglion stimulation
Based on the results of this study, the FDA has approved the use of the AxiumTM for delivering dorsal root ganglion stimulation for certain chronic pain conditions. St. Jude Medical will be rolling out this treatment this year at certain selected pain treatment clinics. Arizona Pain has been selected to be one of the leaders in delivering this new therapy to patients. You can discuss this therapy with your doctor to learn if it may be appropriate for you. Even patients who have failed to get adequate relief with other spinal cord stimulators may be able to benefit from this therapy.
Ted Swing has more than 11 years of research experience in psychology and pain medicine and four years of teaching experience, has published in top psychology and medical journals, and has presented his research at major conferences. He received his Ph.D. in Social Psychology from Iowa State University and has been the Research Director at Arizona Pain since May 2012.