Ep. 49 Pain Procedures: Neuromodulation
Episode Summary:
In this episode, hosts Dr. Dan Bates and Justine Feitelson dive into the fascinating world of neuromodulation, a last step in the treatment algorithm for neuropathic pain. They discuss this technologies application for managing complex pain and other pathologies, the journey from conservative management to a permanent implant, and the different frequencies or mechanism of action of various types of neuromodulation including traditional spinal cord stimulation, dorsal root ganglion (DRG) stimulation, or peripheral nerve stimulation. They cover various risks, expectations, and the multidisciplinary approach necessary for successfully integrating these devices into an overall treatment plan. This episode is a comprehensive guide for anyone considering or curious about neuromodulation therapy.
Episode Overview
Justine and Dr. Dan discuss neuromodulation as the “last house on the block” option for complex pain and neuropathic conditions like CRPS and post‑surgical back pain
Dan discloses extensive research, teaching, and consulting relationships with multiple neuromodulation companies (Nevro, Abbott, Saluda, Biotronik, Presidio, Medtronic), and notes this context for listeners.
It is important to note that neuromodulation is not a cure but one tool within a broader, multidisciplinary pain management plan.
Where Neuromodulation Fits in Treatment
Neuromodulation sits within neuropathic pain management algorithm, after conservative measures (exercise, rehab, psychological support) and first‑ and second‑line neuropathic medications (e.g., amitriptyline, gabapentin, duloxetine, pregabalin) and third line injections/radiofrequency procedures.
Even after trying all appropriate neuropathic medications, about 50% of people still get little or no meaningful pain relief, which is one reason neuromodulation becomes relevant.
Neuromodulation aims to reduce pain and improve function but does not teach the nervous system a lasting pain‑free state; if you turn the device off, pain typically returns.
Types and Targets of Neuromodulation
Neuromodulation leads can be placed in three main locations:
Along the back of the spinal cord (classic SCS).
At the nerve roots (dorsal root ganglion, DRG, stimulation).
In the periphery under the skin over peripheral nerves (peripheral nerve stimulation).
Different patterns of electrical output (“waveforms”) distinguish devices; companies primarily differ in how they make the system “buzz,” which changes how nerves respond and how pain is perceived.
Frequency, Waveforms, and Major Systems
“Low frequency” (also called tonic) stimulation is roughly 30–50 Hz and typically produces a buzzing sensation (paresthesia) in the painful area.
High frequency is defined differently by region (≥10,000 Hz in many Western contexts, ≥1,500 Hz in parts of Asia), but for this discussion high frequency means 10,000 Hz (e.g., Nevro’s system, which is paresthesia‑free).
Abbott’s “burst DR” waveform is designed to mimic physiological firing, affecting both medial (emotional) and lateral (sensory) pain pathways to down‑regulate pain processing.
Medtronic’s DTM (differentiated targeted multiplex) runs multiple low‑frequency waveforms at once, aiming at both neurons and glial support cells (microglia, astrocytes).
Nalu uses a “powertrain” approach with multiple frequencies running on different time frames, again altering nervous system responses to stimuli.
Saluda’s Australian system uses adaptive low‑frequency stimulation (about 30–60 Hz), constantly measuring spinal cord responses and adjusting each subsequent pulse to stay within a therapeutic “dose” range; Dan considers its data set currently very strong and uses it frequently in practice.
Matching Technique to Condition
Most companies have randomized controlled trials focused on post‑surgical neuropathic back pain, making this a primary indication for standard SCS
Abbott’s DRG stimulation has particularly targeted complex regional pain syndrome (CRPS), allowing highly focal targeting of specific nerve roots, which is useful when pain is localized (as in Justine’s own prior treatment).
Peripheral nerve stimulation is useful for very widespread or poorly localizable pain, and for conditions like persistent post‑herpetic pain after shingles, where leads are placed on either side of the painful dermatomes instead of using a spinal cord lead.
From the patient’s side, you typically discuss broad approaches (SCS vs DRG vs peripheral stimulation) rather than specific waveforms or frequencies, which are more in the clinician’s domain.
History and Technological Evolution
Spinal cord stimulation is actually a relatively old technology, first used around 1965.
A major shift happened around 2010 with Nevro’s introduction of paresthesia‑free high‑frequency stimulation, prompting competitors like Abbott’s paresthesia‑free Burst systems.
Over time, devices have improved significantly in comfort, programming flexibility, and battery technology, so people implanted years ago may have very different experiences compared to current and emerging systems.
The Process: From Consideration to Implant
SCS should be embedded in a multidisciplinary program: ongoing rehab, psychological support, and medication management continue before and after implantation.
The pathway typically looks like:
Exhaust appropriate conservative and medication options in a team context.
Consider neuromodulation when these fail to provide adequate benefit.
Undergo a trial, then if successful, proceed to permanent implantation.
Trial Phase
For a trial, temporary leads are inserted into the spinal canal, brought out through the skin, sutured and taped in place; you live with them for about a week while pain and function are assessed.
A “technically” positive trial is defined as at least 50% reduction in pain, but Dan prefers to see around 80% pain reduction plus improvements in function, mood, social activity, and often sleep and medication use, because 50% alone often feels inadequate after 12 months.
Family and partner feedback (“they were much happier this week”) is considered part of the overall trial success picture.
Permanent Implant
If the trial is successful, temporary leads are removed; after about two weeks you return for permanent implantation.
Permanent leads are placed into the spinal canal, tunneled under the skin, and connected to an implanted pulse generator (IPG/battery) placed in soft tissue or fat, usually via two small incisions (midline for leads, buttock/flank for the IPG).
Devices can be:
Non‑rechargeable: often last about 5–6 years.
Rechargeable: often last 7–10 years, with recharge schedules ranging from daily in older systems to as infrequent as every 1–3 months in newer high‑frequency and updated battery designs.
Ongoing Management and Reprogramming
Bodies and nervous systems adapt over time, so stimulation settings may need adjustment; neuromodulation is not a “set and forget” therapy.
Reprogramming visits involve increasing or decreasing intensity and shifting stimulation location (on the contact array) to recapture optimal pain coverage if analgesia wanes or if leads have shifted slightly.
As neuromodulation helps reduce pain and improve function, the plan ideally includes gradually decreasing pain medications while increasing rehab activities.
Risks, Complications, and Side Effects
General procedure‑related risks include infection, bleeding, bruising, and procedure‑related pain, especially if your painful area (e.g., back) is where the access needle passes; trial periods can be extended to let this flare settle before judging benefit.
Specific spinal risks include:
Dural puncture (hole in the dura around the spinal cord) causing a positional headache that usually resolves in a few days; persistent cases are treated with a blood patch.
Rare but serious risks such as spinal cord injury and spinal hematoma (bleed within the spinal canal).
Hardware‑related issues include lead migration or fracture, requiring reprogramming or, if movement is large, surgical repositioning.
IPG “pocket pain” over the battery site is relatively common (about 20–30% of patients) and can be quite bothersome. If this has been an issue for you, give a listen to our “Ask Us Anything” episode (#29) for strategies for managing this.
Seromas (small fluid collections at the incision, often midline) can occur; they tend to come and go and usually resolve on their own, with the key management advice being to leave them alone.
Role and Value of Neuromodulation
Neuromodulation is presented as a powerful but demanding tool: it can provide life‑changing improvements in pain and function for the right person at the right time, but it has real risks and ongoing maintenance needs.
It should not be dismissed outright because of horror stories, but also should not be viewed as a magic cure that replaces rehab, psychological work, and medication management.
The key message is thoughtful evaluation in a multidisciplinary setting, understanding benefits and risks, and making the best decision possible with the information and team support available at the time.