What gets you here

This procedure does not stand on its own. It follows a medial branch block that produced concordant, duration-matched relief on two separate occasions — not one good afternoon, and not a patient’s conviction about which joint hurts. That sequence exists for a reason this page will spend the next few sections defending: the outcomes of ablation track the rigor of the diagnosis that preceded it, almost exactly.

What the heat is actually doing

A thin probe is placed parallel to the same medial branch nerve identified during the diagnostic blocks, its position confirmed under fluoroscopy and often with a sensory and motor stimulation test before any heat is applied. The tip is then heated to roughly 80°C for about ninety seconds, creating a small thermal lesion that interrupts the nerve’s ability to carry pain signal from that joint. It is targeted, it is measured, and it is not guesswork — but it is also not a repair. The joint underneath is unchanged; only its ability to report pain has been switched off.

Why relief is not forever, and why that is not a failure

Peripheral nerves regenerate. That is not a defect in the procedure, it is a basic property of the tissue being treated, and it is the honest answer to why relief from a single ablation typically runs somewhere in the range of nine months to just over a year rather than indefinitely. The nerve fiber regrows along the path the lesion interrupted, at a pace measured in millimeters per week, and once it reconnects, the joint regains its line to the brain.

Patients are rarely told this before the first procedure, and then feel blindsided when relief fades on schedule. It should not be a surprise. It is the expected biology, and it is exactly why this is discussed at the consult, not discovered in month ten.

Repeating it

A repeat ablation at the same joint is a reasonable and common next step once relief from the first has clearly faded, and it does not require re-running the full diagnostic sequence from zero if the original response was clean and the pain pattern has returned identically. What it does require is confirmation that the returning pain matches the original pattern — a different pain in a similar location is a different question, not an automatic repeat.

Cooled radiofrequency, and the sacroiliac joint

Standard radiofrequency creates a lesion roughly the size and shape of the probe tip. Cooled radiofrequency circulates fluid through the probe during treatment, which lets a larger, more spherical lesion form without overheating the tissue immediately around it. That matters most where the target nerves do not run in a single predictable line — which describes the lateral branches supplying the sacroiliac joint far better than it describes the lumbar medial branches. Cooled technique is the more common choice for SI joint denervation for exactly that anatomic reason, detailed further on the sacroiliac joint injection page.

What the trials found, and why this practice still offers it

The evidence here is not uniform, and it should be said plainly rather than smoothed over. Cohort data following patients who were selected using strict, comparative, duration-matched blocks show a large majority obtaining meaningful, months-long relief — consistent with what this practice requires before proceeding. A widely cited 2017 randomized trial found no significant benefit from radiofrequency denervation over sham treatment in chronic low back pain, and it deserves an honest reading rather than a dismissal: it enrolled patients using a single diagnostic block rather than the comparative, duration-matched pair described on the medial branch block page, and a single block is known to carry a high false-positive rate. A trial built on a looser diagnostic gate will enroll patients who were never going to respond to a treatment aimed at a nerve that was not their problem, and the result reads as a failure of the treatment when it may be a failure of patient selection.

This practice’s position, stated plainly: ablation performed on a patient who cleared the stricter diagnostic bar works considerably more often than the mixed trial literature as a whole suggests, and that is the entire argument for insisting on the double-block protocol rather than skipping to treatment on a patient’s say-so.

What it will not fix

This is not a treatment for radicular pain running down an arm or leg — that is a nerve root problem, addressed with an epidural steroid injection or a different workup entirely, not a medial branch. It is also not appropriate for pain that has not been confirmed with blocks, no matter how confidently a scan seems to point at a joint. The scan is not the diagnosis here. The block is.

What happens on the day

Common questions

Related reading

• Medial branch block
• Facet joint pain
• Sacroiliac joint pain
• Failed back surgery syndrome
• How long does a nerve block last?