How Facet Denervation Works: Radiofrequency Heat on the Nerves That Carry Facet Joint Pain

It is the twisting that gives it away. Reaching into the back seat for a bag, turning to check a blind spot, standing up after a long meeting: a deep, dull ache settles just to one side of the spine, sometimes spreading toward a buttock or shoulder blade, never quite tracking down the leg. Scans show wear in the small joints at the back of the spine. Physiotherapy has helped a little. Painkillers help less than they used to.

Somewhere in that story, a pain specialist mentions a facet denervation procedure and says the words ‘radiofrequency’ and ‘burning the nerve’ in the same breath. That phrase alarms people more than the procedure deserves, and reassures them more than the evidence supports.

This explainer walks through what is actually being heated, why a test block comes first, what the day and the following weeks feel like, and what good studies say about how much relief to expect. Every decision along the way stays with your treating team.

What is a facet denervation procedure, in plain words?

A facet denervation procedure is a minimally invasive treatment for pain coming from the facet joints, the paired, thumbnail-sized joints that link each vertebra to the one above and below it. Denervation simply means interrupting a nerve. In this case the target is not the joint itself but the tiny sensory nerve, called the medial branch, that carries pain messages away from it.

The interruption is done with radiofrequency energy: an alternating electrical current that makes the tip of a specially insulated needle warm up. Held against the nerve for a timed interval, that heat damages the nerve’s signal-carrying fibres so they stop transmitting pain. You may hear the same treatment called radiofrequency neurotomy, radiofrequency ablation, rhizotomy or RF denervation. Mayo Clinic and Cleveland Clinic use these terms for the same thing.

Three points frame everything that follows. First, the procedure treats a pain signal, not the arthritis; the joint is no different afterwards. Second, nerves regrow, so relief is temporary by design, though it often lasts months. Third, the treatment only makes sense if the facet joints really are the main source of pain, which is why a diagnostic injection nearly always comes first.

The NHS describes radiofrequency denervation as an option for people with longstanding back pain thought to come from the spinal joints, when other non-surgical approaches have not helped enough. That framing matters: it is a later step, not an opening move, and it sits within a broader plan that usually includes exercise and activity.

Where facet joint pain actually comes from

Picture the spine from behind. Down the middle run the bony spikes you can feel through the skin. Either side of them, at every level, two vertebrae meet at a small, cartilage-lined joint wrapped in a capsule. These facet joints guide bending and twisting and stop the vertebrae from sliding too far. They are true joints, with the same lining and cartilage as a knee, and like a knee they can wear, stiffen and inflame with age or injury.

The capsule of each facet joint is richly supplied with pain-sensing nerve endings. Those endings feed into the medial branch, a fine twig of the larger nerve root that exits the spine at that level. Here is the anatomical detail that shapes the whole procedure: each facet joint receives fibres from two medial branches, one from its own level and one from the level above. Treating one painful joint therefore means addressing two nerves, and two neighbouring joints means three.

Facet-mediated pain tends to be felt as a deep ache over the joint, often worse with leaning backward, twisting or prolonged standing, and it may refer into the buttock, thigh or, in the neck, the shoulder and base of the skull. It does not usually shoot below the knee or cause numbness, which is why it is considered separately from a compressed nerve root.

No pattern of symptoms or scan finding can confirm a facet joint as the pain source on its own. Wear on imaging is common in people with no pain at all. That gap between what a scan shows and what hurts is exactly the problem the diagnostic block is designed to solve.

How radiofrequency heat switches off a nerve

Radiofrequency current does not burn in the way a match does. When the current passes from the exposed metal tip of the probe into the surrounding tissue, water molecules in that tissue vibrate rapidly and generate heat from friction. The probe itself is a conduit; the tissue does the warming. A sensor in the tip monitors temperature so the generator can hold it steady for a set time, producing a small, predictable zone of heated tissue around the active part of the needle.

Nerves are sensitive to heat. Above a certain temperature the proteins in the nerve’s outer coating and its signal-carrying fibres break down, and the nerve can no longer conduct impulses. Because the medial branch is a purely sensory nerve running along a known groove on the bone, it can be targeted without touching the larger motor nerves nearby. The heated zone is elongated along the needle rather than spherical, so the probe is usually laid parallel to the nerve to maximise contact.

Two safety checks happen before any heat is applied. The clinician sends a tiny sensory test current through the probe and asks whether you feel a tingling or pressure in the familiar painful area; that confirms the tip is near the right nerve. A second, motor test current is then used to make sure no muscle in the leg or arm twitches, which would suggest the tip is too close to a motor nerve. Only when both checks are satisfactory does the timed heating begin.

Some centres use a variant called pulsed or cooled radiofrequency, which alters how energy is delivered. Cleveland Clinic notes these exist; they are still the same core idea of interrupting the nerve, and your team will explain which technique they use and why.

Why you will probably have a medial branch block first

A medial branch block is a diagnostic injection in which a small amount of local anaesthetic is placed onto the medial branch nerves, temporarily numbing them. It answers one question: if these nerves are silenced, does the pain go away? If it does, the facet joints are the likely source and denervation of the same nerves stands a reasonable chance of helping. If it does not, denervation is unlikely to help and the search for the pain source continues.

Cleveland Clinic and Johns Hopkins describe this step as standard practice before radiofrequency ablation. The UK guidance summarised by the NHS goes further, expecting a positive response to a diagnostic block before denervation is offered. Many teams ask for two blocks on separate days, sometimes with anaesthetics of different durations, to reduce the chance that a single result was chance or placebo.

The block itself feels much like the denervation day but shorter, with no heating. You will be asked to keep a simple pain diary for the hours afterwards, noting how much the usual ache changed and for how long, and to try movements that normally provoke it. That record is the whole point. A block that gives dramatic relief lasting as long as the anaesthetic usually would is a clean positive; partial or fleeting relief is harder to interpret and is one reason a second block may be requested.

People sometimes feel the block is an unnecessary extra appointment. It is better thought of as the part of the process that protects you from a procedure aimed at the wrong target. A denervation cannot help a nerve that was never carrying your pain.

What actually happens on the day, step by step

Most facet denervation procedures take place in a day-case procedure room or operating theatre with an X-ray machine called a fluoroscope, which gives live images of the bones. You lie face down for the low back or on your back or side for the neck. Skin is cleaned and draped, and a nurse places monitoring for heart rate, blood pressure and oxygen.

Sedation is a conversation to have beforehand. Many teams use only local anaesthetic, sometimes with a light sedative to ease anxiety. Deep sedation is generally avoided because you need to answer questions during the sensory and motor testing described earlier. Feeling drowsy but able to talk is the usual middle ground.

After numbing the skin, the clinician advances the insulated needle toward the bony groove where the medial branch runs, checking position on the fluoroscope from more than one angle. Once the test currents confirm the tip is near the sensory nerve and away from motor nerves, a little more local anaesthetic is delivered through the needle and the radiofrequency heating runs for its timed interval. The needle is then repositioned for the next nerve. Treating one side of two joints, for example, means three nerve targets, and both sides doubles that.

Cleveland Clinic gives a range of roughly fifteen minutes to two hours for the whole session, depending on how many nerves and levels are treated. Afterwards you rest in a recovery area for observation, have a small dressing applied, and go home the same day with someone else driving. A written sheet of what to expect and who to call usually comes with you.

How painful is radiofrequency denervation, honestly?

This is the question people most want answered and least often get a straight reply to. The honest answer is that the procedure is uncomfortable rather than agonising, and the discomfort comes in identifiable moments rather than as a constant.

The first is the local anaesthetic in the skin, a brief sting similar to a dental injection. The second is needle placement against bone, felt as deep pressure. The third is the sensory testing, which is designed to reproduce a version of your usual ache or a tingling in the same area for a second or two; unpleasant, but informative, and it stops as soon as the clinician stops the current. The fourth is the heating itself. Because more anaesthetic is delivered onto the nerve before the current runs, many people feel warmth or a dull pressure; some describe a short, sharp ache that fades within the minute.

What surprises people more is the aftermath. Mayo Clinic and Cleveland Clinic both describe soreness or a burning sensation over the treated area that can last several days to a couple of weeks. Some people notice their back feels temporarily worse than before during this phase, a reaction sometimes called a flare, before settling. Knowing this in advance stops it being frightening.

A facet injection into the joint itself is generally described in similar terms: a sting, then pressure, then relief as the anaesthetic works. Neither procedure should produce severe, escalating pain during or after, and if it does the team wants to know. Ice packs, gentle walking and the simple over-the-counter approaches your team recommends are the usual comfort measures; decisions about any medicine stay with your prescriber.

Who is a facet denervation procedure usually for, and who is asked to wait?

The typical candidate has had back or neck pain for months, felt mainly over the spine rather than down a limb, has tried a structured programme of exercise and other non-surgical care without adequate relief, and has had a clearly positive medial branch block. The NHS summary of UK guidance describes offering radiofrequency denervation to people whose longstanding back pain is moderate or severe and thought to arise from the spinal joints, after non-surgical treatment has not worked. Johns Hopkins lists spinal arthritis of the facet joints as a leading reason for the treatment.

Age alone is not a barrier. Older adults with arthritic facet joints are among the most common candidates, and the absence of a general anaesthetic makes the procedure accessible to people with heart or lung conditions that would complicate bigger operations.

Several situations usually lead a team to postpone or choose a different path:

• A negative or unconvincing diagnostic block, which suggests the pain is coming from somewhere else.
• Pain with clear features of nerve root compression, such as shooting leg pain with numbness or weakness, which points to a different diagnosis and different treatments.
• An active infection anywhere in the body, or skin infection near the injection site.
• Medicines that thin the blood, which need a plan agreed with the prescribing clinician; people should never stop or change these on their own.
• Pregnancy, because fluoroscopy involves X-rays.
• An implanted cardiac device, which requires liaison with the cardiology team about electrical interference before proceeding.

Being asked to wait is not a rejection. Often it means the team is protecting you from a procedure that either would not work or carries avoidable risk in your particular circumstances, and revisiting the plan later is common.

What the evidence really shows about radiofrequency denervation

Here the picture is more mixed than most patient leaflets suggest, and readers deserve the whole of it.

A Cochrane systematic review of radiofrequency denervation for chronic low back pain pooled randomised trials and concluded that the available evidence was of low to moderate quality. For pain believed to come from the facet joints, it found some signal that denervation reduced pain more than a sham procedure in the short term, but the reviewers judged the studies too small and too inconsistent to draw firm conclusions, and they called for larger, better-designed trials.

One such trial followed. The MINT study, published in JAMA, randomised nearly seven hundred Dutch patients with chronic low back pain to a standardised exercise programme with or without radiofrequency denervation. At three months, adding denervation produced no clinically important improvement in pain intensity over exercise alone. Critics argued that patient selection was loose and the diagnostic block criteria generous, so some participants may not have had facet-mediated pain at all; supporters argued it reflected real-world practice. Both readings carry weight.

Clinical guidance has responded by narrowing rather than abandoning the treatment. The UK approach summarised by the NHS keeps denervation for carefully selected people with moderate or severe pain and a positive block, within a plan that continues to emphasise exercise and activity. Mayo Clinic describes relief that can last months, sometimes a year or more, before nerves regrow.

The fair summary: for well-selected patients, denervation can offer meaningful, temporary relief, and it is one of the few interventions for facet pain with any randomised evidence behind it. It is not a guaranteed result, and the better the selection, the better the odds. That is the opinion this article holds, and it is grounded in what the trials actually found.

Facet joint injection vs medial branch block vs denervation: how they compare

Three procedures cluster around the same joints and are easily confused. A facet joint injection places anaesthetic, often with a corticosteroid, directly inside the joint capsule. A medial branch block numbs the nerve outside the joint to test whether it carries the pain. Radiofrequency denervation heats that same nerve to interrupt it for a longer period.

Feature	Facet joint injection	Medial branch block	Radiofrequency denervation
Main purpose	Treat inflammation inside the joint; sometimes diagnostic	Diagnose whether the medial branch carries the pain	Treat by interrupting the nerve
What is delivered	Local anaesthetic, often with steroid	Small volume of local anaesthetic only	Radiofrequency heat, plus local anaesthetic
Target	Joint capsule	Medial branch nerve on bone	Medial branch nerve on bone
Typical duration of effect	Variable; steroid effect measured in weeks	Hours, matching the anaesthetic	Months, until nerve regrowth (Mayo Clinic, Cleveland Clinic)
Usual place in the pathway	Earlier option, or when inflammation is suspected	Gateway test before denervation	After a positive block
Needs imaging guidance	Yes	Yes	Yes

The Cochrane review noted limited evidence that denervation may outperform steroid injection into the joint over the medium term, but again rated that evidence as low quality. In practice the choice is rarely either-or. Many people pass through all three in sequence, and some teams reserve joint injections for episodes where inflammation rather than chronic wear dominates.

Which route suits you depends on how long the pain has lasted, what earlier injections achieved, your other health conditions and the strength of your block result. That weighing belongs to you and your treating team together, not to a table.

What are the risks of a facet denervation procedure?

People searching for ‘risks of denervation surgery’ are often reassured to learn that this is not surgery in the conventional sense: no incision, no general anaesthetic, no hospital stay. That said, any needle placed near the spine carries risks, and a frank list is more useful than a soothing one.

Common and usually short-lived effects, described by Mayo Clinic and Cleveland Clinic, include soreness, bruising or a burning feeling over the treated area for days to a couple of weeks, a temporary flare of the original pain, and small patches of numbness or altered skin sensation near the site. Some people notice a temporary weakness or tired feeling in the small muscles alongside the spine that the medial branch also supplies; this settles as the nerve recovers and is one reason the rehabilitation exercises that follow matter.

Uncommon risks include infection at the puncture site, bleeding, and an allergic reaction to the local anaesthetic or the skin preparation. Rarely, heat or needle injury can affect a nearby nerve, producing longer-lasting burning pain or numbness in the skin. Very rarely, and almost always when technique or anatomy is unusual, motor nerves can be affected; the motor testing step exists precisely to prevent this.

Fluoroscopy involves a small dose of X-ray radiation, which is why pregnancy is a reason to postpone. People with pacemakers or implanted defibrillators need a plan for the electrical current, agreed with their cardiology team.

There is also the risk of it simply not working, or working only briefly, which the evidence section above addresses. Ask your team how they handle a disappointing result, because that answer tells you a lot about how the whole pathway is run.

Radiofrequency ablation recovery time: what the days and weeks look like

The first evening is quiet by necessity. Local anaesthetic and any sedative leave you a little unsteady, so plans are simple: someone else drives, you keep the dressing dry, and you rest but are not confined to bed. Short walks around the home are encouraged; lying completely still tends to stiffen the back.

Days one to three often bring the most noticeable soreness. Mayo Clinic and Cleveland Clinic both describe discomfort at the site and sometimes a burning sensation that can last up to a couple of weeks. Ice wrapped in a cloth for short periods, gentle movement and any comfort measures your team has suggested are the usual approach. Most people return to desk work within a day or two and to light household tasks about the same time; heavier lifting and vigorous exercise generally wait until the team gives the go-ahead.

The middle stretch, roughly the second and third weeks, is when the picture clarifies. Cleveland Clinic notes that the full effect of the treatment may take one to three weeks to appear, as post-procedure inflammation settles and the interrupted nerve stops carrying signals. Judging success on day two is therefore premature in both directions.

From around a month onward, the aim shifts from recovery to rebuilding. Because the medial branch also supplies small stabilising muscles, and because months of pain change how people move, a graded exercise programme is usually part of the plan. The NHS places exercise at the centre of long-term back pain management; denervation is best seen as a window of reduced pain in which to do that work.

Follow-up typically involves a review some weeks later to record how much relief you have and how long it has held. Keep the same kind of diary you kept after the block; it is the most useful information you can bring.

What people often get wrong about facet denervation

‘They burn the nerve, so the pain is gone for good.’ Peripheral nerves regrow. Mayo Clinic describes relief lasting months, sometimes a year or longer, after which pain may return. Repeat treatment is possible and commonly done, but permanence is not what the procedure offers.

‘It fixes the arthritis.’ The joint is untouched. Denervation quiets the messenger, not the message’s cause. Wear, stiffness and the mechanics that provoked the pain remain, which is why exercise and activity stay part of the plan.

‘If the injection helped, the denervation definitely will.’ A positive block improves the odds considerably, and selection is the single most important predictor of a good result. It does not guarantee one. The trial evidence, summarised earlier, shows real variation between people.

‘It is a form of surgery with a long recovery.’ It is a needle procedure done through the skin under local anaesthetic. Cleveland Clinic describes a return to ordinary activities within days, with soreness rather than incapacity in the meantime.

‘A normal scan means it cannot be facet pain, and a bad scan proves it is.’ Imaging correlates poorly with facet-mediated pain in either direction. Many people with striking wear on scans have no pain; some with modest findings have a great deal. The block, not the picture, does the diagnosing.

‘Being sedated fully is safer.’ The sensory and motor testing that protects nearby nerves depends on your being able to report what you feel. Light sedation with local anaesthetic is the usual compromise for good reason.

‘Feeling worse in week one means it failed.’ A temporary flare is a recognised, expected phase. The verdict belongs to the weeks that follow.

Questions to ask your care team before a facet denervation procedure

A good consultation leaves you knowing not just what will happen but why it is being proposed for you specifically. These questions tend to draw out the answers that matter.

• What in my history, examination and block result makes you think my facet joints are the main source of pain?
• How many blocks do you require before denervation, and how strong was my response compared with what you usually look for?
• Which levels and which side will you treat, and how many nerves does that involve?
• What technique and equipment do you use, and will I be lightly sedated or fully awake?
• What should I do about my regular medicines, particularly anything that thins the blood, and who will confirm that plan with my prescriber?
• What does a typical first fortnight look like in your experience, and what would make you want to hear from me sooner?
• How will we judge whether it has worked, and when?
• If the relief is partial or short-lived, what are the next options, and would you repeat the procedure?
• What exercise or rehabilitation do you expect me to do once the pain eases, and who will guide it?
• Are there reasons in my particular case, such as an implanted device or a past reaction to anaesthetic, that change the plan?

Write the answers down or bring someone who will. Ask, too, what the team does not know: an honest clinician will tell you that the response to denervation varies and that the evidence, while supportive for well-selected patients, is not overwhelming. That candour is a mark of quality, not a warning sign.

You are entitled to go away and think. A facet denervation procedure is elective, and a decision made after a night’s sleep is as valid as one made in the clinic.

When to call your doctor after radiofrequency denervation

Soreness, bruising and a temporary flare of the familiar ache are expected and usually settle within days to a couple of weeks. Certain signs are different in kind and should prompt a same-day call to the team that performed the procedure, or emergency care if they are severe or arriving quickly.

Contact the team promptly if you notice:

• Fever, chills or feeling generally unwell in the days after the procedure, or redness, warmth, swelling or discharge spreading from the puncture site, which can indicate infection.
• New weakness in a leg or arm, difficulty walking, foot drop or a limb that will not hold your weight.
• Numbness, tingling or pain that is new, spreading, or affects the saddle area between the legs.
• Any loss of control of bladder or bowel, or difficulty passing urine, which is an emergency.
• Severe or escalating pain that is clearly different from the soreness you were warned about and is not eased by the comfort measures your team advised.
• A severe headache, particularly one that worsens on standing and eases lying down.
• Signs of an allergic reaction such as rash, facial swelling, wheeze or difficulty breathing, which need emergency care.
• Bleeding from the site that does not stop with gentle pressure, especially if you take blood-thinning medicines.

Outside of these red flags, it is still worth calling if relief has not arrived by the time your team said to expect it, or if the pain pattern has changed in a way that puzzles you. Pain services expect these calls and would rather hear early than late.

Nothing in this article replaces the written aftercare instructions you are given, and where the two differ, follow your own team’s advice.

Frequently asked questions

How painful is radiofrequency denervation?

Most people describe it as uncomfortable rather than severely painful. The sting of local anaesthetic, deep pressure as the needle meets bone, a brief tingling during sensory testing and a short ache or warmth during heating are the main moments. Afterwards, Mayo Clinic and Cleveland Clinic describe soreness or a burning feeling that can last days to a couple of weeks before settling.

How painful is a facet injection compared with denervation?

A facet joint injection and a facet denervation feel similar at the start: a skin sting, then pressure as the needle is guided to the joint or nerve. The injection is shorter and has no heating step, so the session is usually briefer. Both are done under local anaesthetic with X-ray guidance, and neither should cause severe or escalating pain.

What are the risks of denervation surgery on the spine?

Facet denervation is a needle procedure rather than open surgery. Common short-term effects are soreness, bruising, a temporary flare of pain and small patches of skin numbness. Uncommon risks include infection, bleeding, allergic reaction and heat or needle injury to a nearby nerve causing longer-lasting burning or numbness. Motor nerve injury is very rare and the testing step is designed to prevent it.

What is the recovery time for denervation surgery?

Cleveland Clinic describes a return to everyday activities within a day or two, with site soreness that can persist for up to a couple of weeks. The full pain-relieving effect may take one to three weeks to become clear as post-procedure inflammation settles. Heavier lifting and vigorous exercise usually wait for your team’s go-ahead, and graded rehabilitation typically follows.

How long does radiofrequency ablation last?

Mayo Clinic describes relief lasting several months, sometimes a year or longer, until the treated nerve regrows and pain signals resume. Cleveland Clinic gives a similar range. Duration varies between people and is not guaranteed. When pain returns, the procedure can often be repeated, and a good response the first time is generally regarded as a favourable sign for a repeat.

What is a medial branch block and why do I need one first?

A medial branch block is a diagnostic injection of local anaesthetic onto the small nerve that carries pain from a facet joint. If numbing the nerve temporarily removes your pain, the joint is the likely source and denervation of that nerve has a reasonable chance of helping. UK guidance summarised by the NHS expects a positive block before radiofrequency denervation is offered.

Facet joint injection vs ablation: which is better?

Neither is universally better; they do different jobs. A facet joint injection delivers anaesthetic and often steroid inside the joint and tends to act over weeks. Radiofrequency ablation interrupts the nerve and tends to act over months. A Cochrane review found only low-quality evidence favouring denervation over steroid injection in the medium term. Your team weighs your history and block result.

Does facet denervation work for everyone with back pain?

No. It is aimed specifically at pain from the facet joints, confirmed by a positive nerve block, and is not suited to pain from a compressed nerve root, a disc or other causes. Even among well-selected people, response varies. The MINT trial found no clinically important benefit over exercise alone when selection was broad, which is why careful assessment matters.

Will I be awake during the facet denervation procedure?

Usually, at least partly. The procedure relies on you reporting what you feel during sensory testing and on the team seeing that no limb muscle twitches during motor testing, so deep sedation is generally avoided. Local anaesthetic, sometimes with a light sedative for anxiety, is the usual approach. Discuss your preferences and any past reactions to sedation with your team beforehand.

Can facet denervation be repeated if the pain comes back?

Yes, repeating the procedure once the nerve has regrown and pain has returned is common practice. Teams generally consider a repeat when the first treatment gave meaningful relief for a worthwhile period. Each repeat involves the same steps and the same small risks, and the decision about timing and suitability rests with your treating clinician based on how you responded before.

References

• Cleveland Clinic: Radiofrequency Ablation
• NHS: Back pain: Treatment

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.