Your Spinal Cord Stimulator Trial Worked. Will the Implant?
- Posted on: Aug 21 2026
A spinal cord stimulator trial can answer an important question: does electrical stimulation meaningfully reduce your pain right now?
What it cannot tell you with certainty is what will happen after the temporary leads are replaced by a permanent system and that system has been in your body for one, three, five, or ten years.
Patients sometimes finish a trial reporting 70%, 80%, or even near-complete relief. It is entirely reasonable to interpret that as a very encouraging result. But it is easy to take the next step mentally and assume:
“If the trial worked this well, the permanent implant should work this well indefinitely.”
Unfortunately, the evidence does not allow us to make that promise.
A successful spinal cord stimulator trial is useful information. It tells us that your pain can respond to stimulation, that you can tolerate the therapy, and that proceeding toward permanent implantation may be reasonable. But it is better viewed as encouraging evidence rather than a guarantee of long-term success.
The important distinction: an SCS trial asks whether stimulation can help. It is much less capable of predicting exactly how much relief you will still have years later.
What Is a Spinal Cord Stimulator Trial?
Before a permanent spinal cord stimulator is implanted, most patients undergo a temporary trial.
One or more thin stimulation leads are placed through needles into the epidural space. Rather than connecting those leads to a generator implanted beneath the skin, the leads are connected to an external device that you use for several days.
During that period, you test the therapy during ordinary daily activities while following restrictions designed to reduce the risk of lead movement or infection.
The temporary leads are then removed. If the trial provides meaningful benefit and the overall clinical picture remains appropriate, permanent implantation may be considered.
It is an unusual advantage in medicine. You can experience the basic therapy before committing to a permanent implanted device.
What Counts as a Successful SCS Trial?
A reduction of approximately 50% or more in the patient’s important pain has traditionally been used as a benchmark for trial success. Functional improvement, sleep, medication use, and quality of life also matter, and no single percentage should replace clinical judgment.
Our threshold is intentionally higher than the traditional minimum.
The commonly used benchmark for a successful spinal cord stimulator trial is approximately 50% pain relief. In our practice, however, we generally hope to see a much stronger response — often in the range of 80% to 90% relief — before we feel particularly confident about proceeding to permanent implantation.
The reason is practical. Neuromodulation results can change over time. A patient who begins with 90% relief may still consider the therapy highly worthwhile years later even if the benefit gradually declines to 50% or 60%. A patient whose trial begins at only 50% relief has much less room for that same decline before the benefit becomes disappointing.
That does not mean a 50% trial is automatically a failure. If a patient clearly understands the uncertainty and feels that the improvement is meaningful enough to justify permanent implantation, we will discuss that option. The decision is individualized rather than based on a rigid number alone.
But percentage pain relief should not be the only question.
A useful trial may also produce meaningful improvement in function. Perhaps you can stand long enough to cook dinner, sleep for several uninterrupted hours, walk farther, sit through a car ride, or perform an activity that your usual pain prevents.
Medication requirements, sleep, activity tolerance, and overall quality of life can also help determine whether the benefit is meaningful.
That distinction matters because pain is not merely a number from zero to ten.
A patient whose pain changes from 8/10 to 4/10 but remains essentially disabled may view the result differently from someone whose pain changes from 8/10 to 5/10 but who can suddenly walk, sleep, work, and participate in family life again.
Does a Successful Spinal Cord Stimulator Trial Predict Long-Term Success?
This is the question patients really want answered.
The answer is: not as reliably as we would like.
In data from the PROCESS study cited in the TRIAL-STIM research program, approximately 95% of patients who proceeded through screening achieved at least 50% pain relief during their spinal cord stimulator trial. At six months after permanent treatment, 48% of patients in the SCS stimulation group achieved at least 50% reduction in leg pain.
These are not perfectly interchangeable measurements or denominators, so they should not be interpreted as saying that “half of successful trials failed.”
They do, however, illustrate the larger point: short-term response during a trial and durable response after permanent implantation are not the same outcome.
The more direct evidence comes from the randomized TRIAL-STIM study.
Researchers compared a strategy in which patients underwent the usual screening trial before permanent implantation with a strategy in which appropriately selected patients proceeded without a screening trial.
At 36 months, 33% of patients in the trial-first group and 31% in the no-trial group were pain responders. There was no significant difference in pain intensity between the groups, nor a difference in the likelihood of device explantation or adverse events.
That does not mean a spinal cord stimulator trial (SCS trial) has no value.
Trials remain standard clinical practice, are generally required before permanent implantation, and provide something research statistics cannot: the individual patient gets to experience stimulation and decide whether the benefit feels meaningful enough to justify an implanted system.
What the research challenges is the assumption that a spectacular trial is necessarily a reliable forecast of an equally spectacular long-term result.
Dr. Amit Sharma & our minimally invasive pain & spine team.
Why Can a Great Trial Work Less Well After Implantation?
There probably is not one explanation.
A temporary spinal cord stimulator trial lasts days. Permanent neuromodulation may continue for many years. A great deal can change during that interval.
Chronic Pain Changes
The underlying disease may progress. Scar tissue, neuropathy, arthritis, spinal degeneration, or another pain generator can develop or worsen.
The pain being treated five years later may therefore not be identical to the pain that responded beautifully during the original trial.
The Nervous System Changes
Neuromodulation interacts with a complex nervous system rather than mechanically repairing a damaged structure. Neural responses can change over time, and some patients experience a gradual loss of efficacy.
Hardware and Lead Position Matter
Lead migration, changes in stimulation coverage, hardware problems, and other technical issues can affect results after implantation.
A Trial Week Is Not Normal Life
A spinal cord stimulator trial is an unusually focused period. Patients monitor their pain closely, speak frequently with the treatment team, receive programming attention, and naturally have substantial hope invested in a new therapy.
Chronic pain also fluctuates. A five-day snapshot can never perfectly represent several years of symptoms.
How Long Do Spinal Cord Stimulators Last?
There are two separate questions hidden inside that question.
The first is how long the hardware lasts. Battery life varies considerably according to the device, programming demands, and whether the system is rechargeable.
The more important question for most patients is:
How long will the therapy continue providing enough benefit that I want to keep the device?
One long-term real-world study followed 400 patients receiving spinal cord stimulation or dorsal root ganglion stimulation. The cumulative risk of device removal for any reason was approximately:
- 17% at three years
- 23% at five years
- 38% at ten years
Removal specifically because pain relief had diminished occurred less often:
- 10% at three years
- 14% at five years
- 23% at ten years
Viewed from the other direction, roughly three-quarters of patients in that cohort had not undergone explantation by five years.
That does not prove that every remaining patient still had excellent pain relief. It does show why explant statistics need to be presented carefully rather than framed either as evidence that stimulation “doesn’t last” or as evidence that every implanted device remains successful.
Why Are Spinal Cord Stimulators Removed?
Loss of adequate pain relief is an important reason, but it is not the only one.
A 2025 systematic review covering more than 13,000 permanent SCS implants found that 1,882 devices were explanted. Across the included studies, inadequate pain relief was the most commonly reported reason for removal, followed by problems such as lead failure and infection.
Other reasons can include:
- Loss or reduction of effectiveness
- Infection
- Lead migration or lead failure
- Hardware malfunction
- Uncomfortable stimulation
- Need for revision
- Changes in the patient’s underlying medical condition
- Occasionally, improvement of the original pain to the point that stimulation is no longer necessary
The important point is that implantation should be thought of as the beginning of long-term neuromodulation management, not simply as the completion of a procedure.
Modern Spinal Cord Stimulation Is Not the Same Technology We Used Years Ago
Long-term explant data deserve attention, but there is another side to the story.
The technology has changed substantially.
Traditional spinal cord stimulation typically relied on tonic stimulation that produced a tingling sensation called paresthesia. Contemporary systems may provide multiple waveforms and stimulation strategies, including paresthesia-free approaches.
Some systems can also adjust therapy based on physiologic feedback or changes affecting stimulation delivery.
These developments matter because they give us more options when the original programming no longer provides the same benefit.
Reprogramming Can Sometimes Rescue a Fading Response
If stimulation becomes less effective, the answer is not automatically device removal.
Depending on the system and the reason for diminished benefit, options may include adjusting stimulation location, intensity, timing, waveform, or other programming parameters.
At the same time, reprogramming cannot solve every problem. Loss of benefit can also reflect lead migration, hardware problems, progression of the underlying disease, a new pain generator, or true loss of efficacy.
The appropriate response is therefore to troubleshoot the problem before declaring the therapy a failure.
Newer Systems Have Produced Encouraging Long-Term Results
It would be equally misleading to discuss only older explant data while ignoring evidence from newer technologies.
For example, the randomized EVOKE trial compared a closed-loop system that measures neural responses and automatically adjusts stimulation with conventional open-loop stimulation.
At 36 months, 77.6% of patients receiving closed-loop stimulation achieved at least 50% reduction in overall back and leg pain, compared with 49.3% receiving open-loop stimulation. Nearly half of the closed-loop group achieved at least 80% pain reduction.
That does not establish that every newer device will produce better ten-year outcomes. It does show why historical data should not automatically be treated as a forecast for every modern neuromodulation system.
The fair conclusion is that the technology is improving, but we still need time to know how much those improvements will change very long-term outcomes.
An Honest Word About the Broader Evidence
Spinal cord stimulation has substantial supporting evidence, but the literature is not uniformly positive.
A placebo-controlled randomized crossover trial published in JAMA in 2022 studied 50 patients with chronic radicular pain after lumbar spine surgery. It did not demonstrate a significant difference in disability between periods of burst stimulation and placebo stimulation.
That study should not be interpreted as proving that spinal cord stimulation does not work.
It evaluated a particular waveform in a specific patient population using a relatively small crossover study. Other randomized trials using different technologies and populations have demonstrated substantial benefit.
But the negative study belongs in an honest discussion of the evidence for the same reason that positive trials do.
The sensible conclusion is not that stimulation always works or that stimulation does not work.
It is that neuromodulation can provide substantial and sometimes extraordinary benefit in appropriately selected patients, but results vary and patient selection remains critical.
Who Is Most Likely to Benefit From Spinal Cord Stimulation?
Neuromodulation is generally most compelling when the dominant pain has a substantial neuropathic component, meaning pain generated by abnormal or damaged neural pathways.
Depending on the individual patient and the specific stimulation technology, conditions considered for neuromodulation may include:
- Persistent neuropathic pain after spine surgery, often described as post-laminectomy syndrome or persistent spinal pain syndrome
- Complex regional pain syndrome
- Painful diabetic peripheral neuropathy
- Persistent radicular pain
- Certain forms of post-surgical nerve pain
For certain focal neuropathic pain syndromes, dorsal root ganglion stimulation may provide another neuromodulation strategy with the ability to target a more specific anatomic region.
Diagnosis Still Comes Before Stimulation
One principle matters regardless of how sophisticated the device becomes:
Neuromodulation should not become a substitute for figuring out why the patient hurts.
Before considering permanent stimulation, the clinical evaluation should establish as clearly as possible what type of pain is being treated and whether another correctable pain generator remains.
Depending on the presentation, that process may involve examination, imaging, or targeted diagnostic procedures such as a selective nerve root block.
Some patients may still have a more direct treatment available. For example, appropriately confirmed facet-mediated pain may respond to radiofrequency ablation. Structural compression may require a completely different strategy.
The purpose is not to force every patient through every possible procedure before stimulation.
It is to make sure we are using neuromodulation for a pain problem that neuromodulation actually makes sense to treat.
What If My Spinal Cord Stimulator Stops Working?
A decrease in pain relief does not automatically mean the device needs to be removed.
The first step is usually to understand what changed.
Questions may include:
- Has the location or character of the pain changed?
- Is the original pain returning or is this a new pain generator?
- Has stimulation coverage changed?
- Could a lead have migrated?
- Is there a hardware problem?
- Are additional programming options available?
- Has the underlying spinal or neurologic condition progressed?
Modern systems may provide multiple programming strategies, and reprogramming should generally be explored when appropriate before concluding that the therapy has permanently lost effectiveness.
But sometimes a device truly stops providing enough benefit. When that happens despite reasonable troubleshooting, revision or explantation may eventually become appropriate.
Questions to Ask Before Permanent Implantation
- What exactly are we treating?
Has the dominant pain generator been identified as clearly as reasonably possible? - What improved during my spinal cord stimulator trial?
Was it only my pain score, or did my walking, sleeping, activity, and quality of life improve? - How much relief would make a permanent implant worthwhile to me?
That answer may differ from one patient to another. - What happens if the benefit decreases?
What programming and troubleshooting options does this particular system provide? - Who will manage my device after implantation?
Neuromodulation requires long-term follow-up, not simply a procedure and discharge. - What MRI access will I have?
Understand the MRI-conditional status and any restrictions associated with the specific device being considered. - Is the system rechargeable?
If so, realistically consider whether regular charging fits your lifestyle. - What would make us decide to revise or remove it?
It is worth discussing failure pathways before implantation rather than discovering them later.
Our Position on Spinal Cord Stimulation
We offer neuromodulation, including spinal cord stimulation and dorsal root ganglion stimulation, because we have seen patients obtain relief that other treatments were unable to provide.
For some patients, the improvement can be remarkable.
We have also seen stimulation become less effective over time, devices require revision, and implants ultimately removed. We cannot always predict beforehand which patient will follow which path.
That uncertainty does not make spinal cord stimulation a poor therapy. It makes patient selection and realistic expectations particularly important.
For the right patient, with the right type of pain, after the appropriate diagnostic work and reasonable alternatives have been considered, spinal cord stimulation can be an entirely rational next step.
A successful trial strengthens that decision.
It simply does not guarantee the future.
A great spinal cord stimulator trial should make you optimistic.
It should not make anyone promise you a permanent result.
If you are considering spinal cord stimulation, deciding whether to proceed after a trial, or dealing with a device that no longer works as well as it once did, the most useful next step is often a detailed discussion of what the trial actually showed and what your realistic long-term options are.
Dr. Amit Sharma & our minimally invasive pain & spine team.
Frequently Asked Questions
How long does a spinal cord stimulator trial last?
A spinal cord stimulator trial generally lasts several days, although the exact duration varies. Temporary leads are placed into the epidural space and connected to an external stimulator. During the trial, the patient evaluates pain relief and functional improvement while following precautions intended to reduce lead movement and infection risk.
What percentage of pain relief counts as a successful SCS trial?
Approximately 50% pain reduction has traditionally been used as an important benchmark to define spinal cord stimulator trial, but pain percentage alone does not capture the entire result. Meaningful improvements in walking, sleep, activity, function, medication use, and quality of life may also help determine whether the trial provided enough benefit to justify permanent implantation.
Does a successful spinal cord stimulator trial guarantee that the permanent implant will work?
No. A successful spinal cord stimulator trial demonstrates that the patient’s pain can respond to stimulation over a short period and provides useful information before permanent implantation. Research suggests, however, that a short screening trial does not reliably predict the magnitude or durability of long-term benefit. A strong trial should therefore be considered encouraging evidence rather than a guarantee.
Why can a spinal cord stimulator work during the trial but less well later?
Several factors may contribute. Chronic pain and the underlying disease can change, neural responses may evolve, leads can move, hardware issues can occur, and a new pain generator may develop. A spinal cord stimulator trial also samples only a few days of a condition that may continue for many years.
How often are spinal cord stimulators removed?
Rates vary across studies, devices, patient populations, and length of follow-up. In one 400-patient long-term cohort that included SCS and DRG stimulation, cumulative explantation risk for any reason was approximately 17% at three years, 23% at five years, and 38% at ten years. Removal specifically because of diminished pain relief was approximately 10%, 14%, and 23% at those same intervals.
What if my spinal cord stimulator stops working as well?
A decrease in benefit should be evaluated before assuming that the device has permanently failed. Reprogramming may help in some patients. Other possibilities include lead migration, hardware problems, progression of the underlying condition, or development of a new pain generator. The correct treatment depends on why the response changed.
What kind of pain responds best to spinal cord stimulation?
Neuromodulation is generally most compelling when pain has a significant neuropathic component. Depending on the individual patient and device, this can include persistent neuropathic pain after spine surgery, complex regional pain syndrome, painful diabetic neuropathy, radicular pain, and certain other chronic neuropathic pain disorders.
Are newer spinal cord stimulators better than older devices?
Modern systems offer more stimulation strategies and programming options, and some newer technologies have produced encouraging long-term clinical trial results. However, different systems work differently, and very long-term data require years to accumulate. Newer technology is promising, but no device can guarantee permanent pain relief.
References
- Eldabe S, et al. Does a screening trial for spinal cord stimulation in patients with chronic pain of neuropathic origin have clinical utility and cost-effectiveness (TRIAL-STIM)? A randomized controlled trial.
PMC - Eldabe S, et al. Does a Screening Trial for Spinal Cord Stimulation in Patients With Chronic Pain of Neuropathic Origin Have Clinical Utility (TRIAL-STIM)? 36-Month Results From a Randomized Controlled Trial. Neurosurgery. 2023;92(1):75-82.
PubMed - TRIAL-STIM study protocol discussing screening-trial evidence and prior PROCESS trial data.
PMC - Long-term explantation risk in patients with chronic pain treated with spinal cord or dorsal root ganglion stimulation. Regional Anesthesia & Pain Medicine.
PubMed - Wahezi SE, et al. Spinal Cord Stimulation Explantation and Chronic Pain: A Systematic Review and Technology Recommendations. Journal of Pain Research. 2025.
PubMed - Hara S, et al. Effect of Spinal Cord Burst Stimulation vs Placebo Stimulation on Disability in Patients With Chronic Radicular Pain After Lumbar Spine Surgery: A Randomized Clinical Trial. JAMA. 2022;328(15):1506-1514.
PubMed - ECAP-controlled closed-loop versus open-loop spinal cord stimulation for chronic pain: 36-month results of the EVOKE randomized clinical trial.
PubMed - Shanthanna H, et al. Evidence-based consensus guidelines on patient selection and trial stimulation for spinal cord stimulation therapy for chronic non-cancer pain. Regional Anesthesia & Pain Medicine. 2023;48(6):273-287.
PubMed - Chapman KB, et al. Dorsal root ganglion stimulation device explantation: a multicenter pooled data analysis. Pain Practice. 2022.
PubMed
Tagged with: Chronic Pain, Failed Back Surgery Syndrome, Nerve Pain, Neuromodulation, Spinal Cord Stimulation, Spinal Cord Stimulator Trial
Posted in: News, Special Report
