As interventional pain management therapies rapidly advance, more patients suffering from chronic neuropathic pain could experience relief and quality-of-life improvements from these new treatment options.

According to M. Gabriel Hillegass, M.D., a board-certified interventional pain management physician at MUSC Health, neuromodulation advances related to spinal cord stimulation and radiofrequency ablation are two particularly exciting treatment avenues offering patients excellent results for chronic pain, such as back and joint pain.

Spinal Cord Stimulation for Chronic Back Pain

Neuromodulation uses implanted devices or special needles to treat nerve pain with electrical stimulation. In spinal cord stimulation, an outpatient neuromodulation therapy, electrodes are carefully placed in the epidural space over the spinal cord to override nerve pain signals, thus relieving patients’ pain.

According to Dr. Hillegass, neuromodulation technologies have seen exciting advances in the past 5 years.

“Neuromodulation technologies are developing quickly. In spinal cord stimulation, applications can not only stimulate the nerves along the spinal cord but also the dorsal root ganglion, which is a cell body of the sensory nerves that just exit the spinal cord. Still under development, but soon to come, will be targeted peripheral nerve stimulation applications,” he says.

For spinal cord stimulation procedures, a device consisting of a battery generator and attached wire leads (analogous to a cardiac pacemaker) is implanted under a patient’s skin. Similar to how a pacemaker regulates heart function, this implant modulates the nervous system.

“Stimulation procedures are pretty stable therapies,” says Dr. Hillegass, noting that the most common complications involve the device’s battery, which may need replacement after several years, or an electrical lead moving, which requires a revision surgery to reset the lead.

Recent advances in neuromodulation therapies:

  • Treating neuropathic pain: Technology advances have made significant strides in treating difficult-to-treat neuropathic pain, particularly post-laminectomy syndrome, or failed back surgery syndrome. Sometimes, someone who has undergone spine surgery still has persistent back pain, often with associated arm or leg pain. This neuropathic pain, or pain arising from abnormally firing nerves, could be due to injury, inflammation or scar tissue.
  • Better delivery: “Within the past 2 to 3 years, the waveforms (or pulse patterns) that the spinal cord stimulators deliver have improved dramatically,” says Dr. Hillegass. “We’re now better able to treat back pain, which we couldn’t do previously with traditional (tonic or paresthesia-based) spinal cord stimulation. Additionally, these novel waveforms are not felt by the patient and seem to have less tolerance than traditional stimulation.”
  • Advanced techniques: An innovative technique stimulates the dorsal root ganglion directly, so doctors can better target specific nerves and potentially help more patients with chronic pain involving a specific nervous distribution.
  • MRI-compatibility: Some newer spinal cord stimulation devices are also MRI-compatible, so patients will be able to undergo an MRI scan, should they need one in their future.

Radiofrequency Ablation for Chronic Joint and Knee Pain

In radiofrequency ablation procedures, specialists attempt to decrease pain signals by using a special needle to lesion a particular nerve, primarily with heat. Here, too, advancing technologies offer more applications for this therapy’s use in chronic pain management.

“Traditionally, radiofrequency ablation was used for facet joints along the spine. We are now starting to learn how to perform these procedures to relieve chronic knee pain, hip pain, groin pain as well as other indications,” says Dr. Hillegass.

One new application of this innovative therapy that’s already in use at MUSC is called COOLIEF. This procedure uses cooled radiofrequency energy to target and treat sensory nerves causing chronic pain such as knee pain.

Because all nerves will try to grow back, radiofrequency ablation procedures are not a permanent fix. The treatment effect tends to last an average 9 to 12 months, so it is often repeated at intervals, depending on a patient’s response to the therapy.

“As we learn more about how to apply radiofrequency ablation to peripheral joints such as the knees and the hips, this procedure may be a new treatment option for patients who are not candidates for joint replacement surgery or those with chronic postsurgical pain and other peripheral nerve pain syndromes,” says Dr. Hillegass.

Interventional Pain Management: Potential Complications

Complications of interventional pain management procedures include:

  • Rarely, infection and nerve injury
  • Spinal cord injury, also rare but possible, depending on the area of interest
  • Procedure does not provide the expected duration of pain relief—the most likely complication

To avoid the problem of insufficient pain relief after more advanced procedures such as spinal cord stimulation, Dr. Hillegass performs a trial with a spinal cord stimulator before implanting the system in any patient.

“The lead is externalized coming through the skin, and the lead and battery are sterilely taped to a patient’s back. Then, we ask a patient to live his or her life with the stimulation on for a week, so we can determine how much pain relief they had and how much their function improved,” explains Dr. Hillegass.

Interventional Pain Management Care Considerations

Before patients are considered candidates for interventional pain therapies:

  1. Evaluation: Doctors complete a thorough assessment, including a comprehensive history and physical and review of previous therapies and interventions.
  2. Diagnostic tests: In some cases, electrodiagnostic or imaging studies may be warranted to confirm that the source of a patient’s pain is coming from the expected nerve distribution.
  3. Psychological screening: Most insurance policies require a psychological evaluation for patients who are considering spinal cord stimulation. “If a patient has a severe untreated psychiatric disorder, such as severe depression, then they’re not a good candidate for the therapy at that time. Patients may need to optimize their mental health prior to pursuing any of these advanced interventional pain options,” says Dr. Hillegass.

At MUSC Health, those mental health resources can be found all under one roof. “As an academic medical center, we have resources throughout the university in terms of mental health support and robust addiction medicine services, both inpatient and outpatient. We’re able to collaborate easily with interdisciplinary teams to take care of patients with complicated pain histories,” he explains.

New Potential for Chronic Pain Relief

Patients who were previously not suitable candidates for standard interventional pain management therapies may be a better fit for these newer therapies.

The number of patients who could see relief from these therapies—and the potential quality-of-life improvements—is sizeable, says Dr. Hillegass.

“Patients who had failed back surgery and are not doing well on conservative therapies should be referred for evaluation for some of these advanced interventional pain options. It could dramatically decrease patients’ reliance on chronic opioids, which is a major problem in our country. These interventional pain management treatments are proving to be effective therapies. Patients experiencing chronic pain would benefit from exploring these new options,” he says.

For more information, contact Dr. Hillegass at hillegass@musc.edu.