Why Your Leg Still Burns After a Back Surgery That Worked

What this video covers

• Why nerve pain keeps firing after the first injury has healed, and what dorsal horn sensitization really means
• How conventional stimulation recruits large A-beta fibers in the dorsal columns. Why the classic gate-control explanation still rests mostly on animal models. How 10 kHz and burst waveforms ease pain without a buzzing feeling, through different and still-debated mechanisms
• What closed-loop stimulation adds. The device measures the evoked compound action potential (the nerve’s own electrical response) and adjusts every pulse as the cord moves with posture and breathing
• What the trials really measured. That includes the 83.1 percent versus 61.0 percent twelve-month rates for pain relief of 50 percent or more without more pain medication in the blinded Evoke trial. It also covers why the much larger gap in the unblinded SENZA-PDN diabetic neuropathy trial needs more caution
• Where the evidence is truly weak. That includes a 2023 Cochrane review of chronic low back pain. Most of its trials were not limited to patients who had never had surgery. It also covers the specialty-society rebuttals to it
• The risks you would be agreeing to. Infection led to device removal in about 2 percent in the diabetic neuropathy trial. Add lead migration, dural puncture, the rare risk of epidural hematoma or nerve injury, loss of effect over time, and a real chance of revision surgery or explant
• MEDICAL DISCLAIMER: This content is for educational purposes only and is not medical advice. It does not substitute for professional diagnosis or treatment. Always consult a licensed healthcare provider regarding your condition. Viewing this video does not establish a doctor-patient relationship.

Leg pain persists after a successful back surgery because the operation fixed the structure, not the nerve. Damaged nerve fibers keep firing on their own. The spinal cord relay above them keeps turning up that signal. Before anyone calls the nerve permanently damaged, a selective nerve root block checks whether the treated level is the one causing the pain.

Eleven months after the laminectomy, the MRI shows a wide-open canal and no new disc problem. And a line of electric burning still runs from your buttock, down the back of your thigh, into the outside of your foot. Worse at night. Unmoved by gabapentin, or by a higher dose of it. Your leg is numb and it hurts at the same time.

Before you decide the nerve is permanently damaged, ask one question. Is the level that was treated the level causing the pain? A selective nerve root block answers that directly. Also, the deep gluteal structures can cause the same leg pain with no nerve root involved at all.

The imaging has cleared your spine. Nobody has said the sentence that actually explains you: the structure was corrected and the nerve was not. This article explains what is physically causing that line down your leg. It covers why you get that exact mix of numbness and burning, and what the usual next steps miss. It also shows what an honest workup for neuromodulation (nerve-signal treatment) looks like. That includes the trial evidence that does not make it into the device brochures.

Why does nerve pain in the leg continue after back surgery?

If there is nothing left in the canal to blame, what generates an electric line down your calf?

Damaged nerve fibers (axons) do not simply go quiet. They fire spontaneously. This is ectopic discharge, a signal with nothing setting it off. That barrage travels up into the dorsal horn. That is the relay station in the back of your spinal cord. Incoming sensory traffic gets sorted there before it goes to the brain. Under a steady barrage, that relay changes state:

• Thresholds fall. Relay nerve cells that once needed a real injury to fire start firing for much less.
• Receptive fields widen. The area a single nerve cell answers for grows. So pain spreads past the first nerve’s strict border.
• Descending inhibition loses its grip. The brainstem fibers that normally turn the volume down stop doing their job well.

You are left with a spinal cord that turns signals up instead of filtering them. That is why an operation that fixed the structure can leave the pain untouched. Surgery treats anatomy. Nothing in a decompression reaches the state of the circuit above it.

Why is my leg numb and burning after back surgery?

The numbness and the burning are not competing descriptions of the same leg. They are two halves of one problem.

Numbness is loss. Fibers have stopped reporting. That is why sensory testing across that area comes back dulled. The burning comes from somewhere else. It comes from the firing described above, and from the boost that firing drives in the dorsal horn. One is a signal that stopped. The other is a signal being made further down the line. They can exist in one limb at once because they are not the same event.

The pattern down the limb is not random either. Some pain follows a nerve’s path, such as buttock to back of thigh to outer foot. That pain is called radicular or dermatomal. It points to a nerve problem, not a joint or muscle problem. Burning, electric pain in a nerve’s path, with sensory loss, is what “neuropathic” actually means in a clinic. It is a different thing from mechanical axial back pain. That is the deep ache across the low back that changes with position and load. The difference is not academic. It decides whether the treatment below should be offered to you at all.

What the usual next steps miss

There is a well-worn path for people in this gap. In practice, all three branches can fail the same person in the same year. That is what we see in this practice, not a published rate, and individual experience varies.

Re-imaged and handed back. The scan is normal, so the visit ends. But the scan was never going to show an overexcited dorsal horn. A normal MRI does not mean nothing is wrong. It means the thing that is wrong is not a shape.

Operated on anyway. Fusion, then extension of the fusion. Each round adds hardware and changes nothing about the burning. If the source is a rewired circuit, a fourth operation cannot find it.

Escalated on medication until you are sedated and still hurting. Medications for nerve pain have a real place. But they only treat symptoms. The benefit lasts while you take the drug. It does not change the state of the cord. Do not start, stop, or change any medication without consulting your physician.

And when neuromodulation finally comes, it too often shows up as hardware. A device is offered before anyone has shown that your pain is truly neuropathic. No one has explained what the evidence does and does not show.

What does a spinal cord stimulator do for leg pain?

Spinal cord stimulation places electrodes in the back of the epidural space, just outside the covering of the spinal cord. They sit over the dorsal columns, the highways of large A-beta fibers.

Conventional low-frequency stimulation recruits those large fibers first. The classic explanation is gate control. Activity in large fibers closes a gate on pain signals in the dorsal horn. Note how carefully that has to be said. The gate-control model, and the dorsal-horn GABA mechanisms tied to it, come mostly from animal work and remain incompletely confirmed in humans. It is the best account we have, not a proven human mechanism.

High-frequency 10 kHz and burst waveforms work below the paresthesia threshold. You feel no buzzing at all. Because they cause no buzzing, they are not working by classic gate control. Their mechanisms are genuinely debated. Anyone who tells you the mechanism is settled is reading you marketing.

There is also a physical problem a fixed-output device cannot solve. Your spinal cord floats in spinal fluid. It drifts toward the lead when you lie on your back and away from it when you stand. It sways with every breath. Meanwhile, the current’s strength drops steeply with distance. So a fixed output overshoots and undershoots all day. Closed-loop stimulation is the engineering answer. The lead records the evoked compound action potential. That is the real electrical response the nerve fibers make to each pulse. Then it corrects the next pulse to keep nerve activation inside a helpful range.

Who is a good candidate for spinal cord stimulation?

Four questions come before any talk of a device. If no one has answered them, you are being sold hardware.

1. Is the pain neuropathic, or is it mechanical axial back pain? Burning, electric pain in a nerve’s path, with sensory loss, is one thing. A mechanical ache across the low back is another. A stimulator has no business treating it.

2. Is there a structural lesion still correctable? Recurrent herniation, foraminal stenosis, pseudarthrosis (a fusion that never solidly healed), adjacent segment disease. MRI answers most of these questions. Pseudarthrosis needs thin-slice CT and bending X-rays (flexion-extension films). That is because a fusion that looks solid on a plain X-ray is not always solid under load. Where imaging and symptoms disagree about which level is talking, a diagnostic selective nerve root block settles which root is causing the pain.

3. Is the pain focal at all? Widespread nociplastic pain is not a target for a lead in the epidural space. This is pain that comes from changed pain processing, not from tissue or nerve damage you can point to. Hardware placed into that problem mostly adds scar.

4. Psychological readiness. The honest answer here is softer than the field usually admits. Untreated depression is the one mental health factor that predicts poor long-term results with any consistency across the research. Catastrophizing (expecting the worst) and active substance use have predicted outcome in some series and not in others. There is no good evidence that the screening visit by itself improves anyone’s result. Screening is still worth doing. Not because a questionnaire predicts your future. It is because treating a collapsed mood or an untreated substance problem first is better medicine than finding it with hardware already in your back.

None of those four questions is worth asking until the basic work is behind you and documented. That means a real course of physical therapy, the right medication trials, and targeted diagnostic and therapeutic injections. This is not a first-line treatment and it is not a shortcut past one.

The trial — and why it is not a free week

Only after that record exists does a trial make sense. You lie face down under live X-ray (fluoroscopy). A Tuohy needle enters the epidural space by an interlaminar approach (between the bones of the spine). Loss of resistance, the sign the needle has reached that space, is confirmed on imaging, not by feel. Thin leads go in through the skin up to the low thoracic (lower mid-back) levels. They are then left externalized through the skin while you keep a log of pain and function. If both do not improve, nothing permanent is implanted. The leads come out at the bedside. Our spinal cord stimulation treatment page walks through the staging, the lead placement and the implant step by step.

That is a real advantage over most surgery. You find out before you commit. But it is not a free week, and no one should call it one. A trial is still an epidural procedure, with infection at the exit site, dural puncture, and bleeding. It is a small, limited, reversible risk taken on purpose. The other path is a large, permanent risk taken on faith.

What the evidence shows — including the part that is inconvenient

Three studies carry most of this talk. Each one needs its limits attached.

Closed-loop versus open-loop (Evoke, 2020). Mekhail and colleagues published a double-blind randomized trial in Lancet Neurology. It compared closed-loop against open-loop stimulation in chronic back and leg pain. At twelve months, 83.1% of closed-loop patients (49 of 59) achieved at least 50% pain relief without increasing pain medication, versus 61.0% (36 of 59) on open-loop.¹ Read that for exactly what it is. Both arms had a stimulator running. It tells you that a device measuring the nerve’s response beats one that only guesses. It does not tell you that either one beats placebo, because there was no placebo arm. Saluda Medical, the maker of the closed-loop system, funded the trial.

10 kHz stimulation in painful diabetic neuropathy (2021). Petersen and colleagues, in JAMA Neurology, reported that 79% of stimulation patients responded at three months against 5% on medical management alone. By six months, average pain in the stimulation group had fallen from 7.6 to 1.7 cm on a visual analogue scale (a pain line). The medical-management group went from 7.0 to 6.9. It did not move.² That gap looks spectacular, and you should still discount it. The trial was open-label with no sham arm. An unblinded comparison against pills overstates what the device itself adds. Nevro Corp, the maker, funded it. If your problem is painful diabetic neuropathy, not leg pain after surgery, the workup that must come first is on our diabetes and neuropathy page.

The Cochrane review (2023). Traeger and colleagues reviewed 13 trials and 699 participants with chronic low back pain. They concluded that stimulation probably does not deliver sustained clinical benefit that outweighs its costs and risks. They also found the data do not support its use for low back pain outside a clinical trial.³ That review is not a footnote, and it does not get skipped. Here is the part that usually gets lost: it is not about somebody else. Its trials were not limited to people who had never had spine surgery. So it applies directly to readers in exactly the situation this article describes. Specialty societies have publicly disputed the review. That dispute is worth knowing about, and it does not cancel the finding. The review should raise the proof you demand before anything is implanted. First, decide whether the pain is neuropathic or axial, and write it down. Then run a reversible trial that has to earn the implant. Do not accept a device offered on the strength of a brochure.

The risk sheet, in full.

• Infection, sometimes requiring removal of the whole system. In the diabetic neuropathy trial, 2% required explant for infection.²
• Lead migration. The lead shifts, and the therapy can stop covering your pain area.
• Dural puncture, with a headache that changes with position and can last for days.
• Epidural hematoma, or direct injury to the spinal cord or a nerve root. These are rare, and they are why this is a real consent talk and not just a signature. A bleed pressing on the cord in the thoracic epidural space can leave permanent weakness, or paralysis, if it is not caught and decompressed (relieved by surgery) within hours. You have a right to hear that sentence before a needle goes near your cord, not after.
• Revision surgery. In one low back pain trial in the Cochrane review, 13 of 42 people (31%) receiving stimulation needed revision surgery within 24 months.³
• Loss of effect over time. Some patients choose explant. An implanted system also puts lasting limits on future MRI scans. Those limits must be reviewed with you before a trial.

An honest picture of what “better” looks like

What follows is a composite. It is a picture built from many patients with this condition, not one person’s chart.

Someone two years past a lumbar decompression and fusion. Leg pain electric and unbearable. Two surgeons said there was nothing left to decompress. The exam showed sensory loss along one nerve’s path with allodynia. That means ordinary touch reads as injury. Screening flagged collapsed sleep and low morale, and those were treated first.

The trial week is where a composite stops being tidy. Dressings, no showering, wires taped along the back, and the strange work of judging a treatment while wearing it. Relief was partial. The leg pain was much better. The axial ache did not change. That is the usual pattern, and it needs saying before, not after. Then came programming visits over two months and a winter of physical therapy. Blood sugar control and anti-inflammatory eating ran alongside all of it. That is because an exit site and a fresh implant pocket heal better in a body without high blood sugar. Those steps supported the procedure. They did not replace it, and they should not be sold as if they had.

At a year, the leg pain was manageable and the opioid dose was lower. Not absent. Not cured. That is what success looks like after a decompression that fixed the anatomy and did not repair the nerve. It is a leg you can stand on, not a leg you stop noticing. Some patients never reach even that. It belongs in the talk before the trial, not after. Individual results vary.

Frequently asked questions

Addresses, hours and directions are listed on our Locations page.

Key takeaways

• Lasting burning leg pain after a technically successful decompression is usually a rewiring problem. Injured nerve fibers fire on their own and the dorsal horn becomes overexcited. So the cord turns signals up instead of filtering them.
• Numbness and burning in the same leg do not contradict each other. One is a signal that stopped. The other is a signal made further down the line. Sensory loss plus burning in a nerve’s path is exactly what “neuropathic” means.
• Spinal cord stimulation targets that circuit through leads over the dorsal columns. The classic gate-control explanation comes mostly from animal work and is not fully confirmed in humans. The mechanisms of 10 kHz and burst waveforms are still debated.
• Closed-loop devices measure the evoked compound action potential and correct each pulse as the cord moves in spinal fluid. The trial supporting them compared closed-loop with open-loop, not with placebo.
• A 2023 Cochrane review of 13 trials and 699 participants found stimulation probably does not deliver lasting benefit that outweighs its costs and risks in chronic low back pain. Its trials were not limited to patients who never had surgery, so that conclusion applies to readers after surgery too. Societies dispute it. The honest response is stricter selection and a trial that has to earn the implant, not a device sold on a brochure.
• This is not first-line care. All of these come before any permanent implant: a documented course of conservative treatment, a clear call on neuropathic versus axial pain, ruling out a structural problem that can still be fixed, psychological screening, and a reversible trial with leads that come out through the skin.

This article is educational and is not a substitute for evaluation, diagnosis, or treatment by a physician. Individual results vary. Do not start, stop, or change any medication without consulting your physician. If the surgery is behind you, the imaging is unremarkable, and the leg is still burning, call (314) 481-5000 or text (314) 886-5902 to arrange an evaluation of whether your pain is genuinely neuropathic.

References

1. Mekhail N, Levy RM, Deer TR, et al. Long-term safety and efficacy of closed-loop spinal cord stimulation to treat chronic back and leg pain (Evoke): a double-blind, randomised, controlled trial. Lancet Neurol. 2020;19(2):123-134. PMID 31870766. PubMed
2. Petersen EA, Stauss TG, Scowcroft JA, et al. Effect of high-frequency (10-kHz) spinal cord stimulation in patients with painful diabetic neuropathy: a randomized clinical trial. JAMA Neurol. 2021;78(6):687-698. PMID 33818600. PubMed
3. Traeger AC, Gilbert SE, Harris IA, Maher CG. Spinal cord stimulation for low back pain. Cochrane Database Syst Rev. 2023;3(3):CD014789. PMID 36878313. PubMed

Medically reviewed by Dr. Gurpreet Singh Padda, MD, MBA, MHP — Board Certified in Anesthesiology, Pain Medicine, Interventional Pain Management, Addiction Medicine, and Obesity Medicine. Last reviewed July 2026.

Dr. Gurpreet Singh Padda, MD, MBA, MHP