Months after a rear-end collision, the neck pain has not settled. Imaging shows degenerative change, physical therapy has plateaued, and the next appointment on the calendar is a surgical consultation. That is the point at which a great many injured people agree to a cervical fusion — not because fusion was proven to be the answer, but because it was the only option anyone put in front of them.

There is a step that belongs before that decision, and it is diagnostic rather than surgical.

Where post-collision neck pain usually comes from

The cervical facet joints are the small paired joints at the back of each vertebral level. They guide motion and they take load, and in a whiplash mechanism — rapid extension followed by flexion — they are among the structures most reliably injured.

Published prevalence work using controlled diagnostic blocks has put cervical facet joint involvement at roughly half of chronic neck pain after a collision, with individual studies ranging higher or lower depending on the population and the diagnostic threshold used. That matters because facet-mediated pain does not appear on an MRI as a discrete lesion. The imaging looks like ordinary degeneration, which is precisely why it is so often attributed to age rather than to the crash.

The diagnostic step that settles the question

The medial branch nerves are small sensory nerves that carry pain signals from each facet joint. They can be anesthetized individually.

A medial branch block places a small volume of local anesthetic at those nerves. If the pain that has resisted months of conservative care goes quiet for the duration of the anesthetic, the facet joint is the pain generator. If nothing changes, it is not — and a great deal of unnecessary treatment has just been avoided.

The convention in interventional practice is to perform two blocks rather than one, because a single positive block carries a meaningful false-positive rate. Two concordant responses, each producing a high degree of relief, is the standard that supports proceeding.

What radiofrequency ablation actually does

If the blocks confirm the facet joints, radiofrequency ablation treats them. A probe is positioned at the same medial branch nerves and heated, interrupting their ability to transmit pain signals from that joint.

It is worth being precise about what this is and is not:

• It is an outpatient procedure, performed with local anesthetic and light sedation rather than general anesthesia.
• It does not fuse, remove, or replace any structure. Nothing is permanently altered in the spine’s mechanics.
• The nerves regenerate. Relief is durable but finite — reported ranges commonly fall between several months and roughly two years, after which the procedure can be repeated.
• If it does not work, every surgical option remains open. Nothing has been foreclosed.

Reported success rates in the published literature typically describe around half to two-thirds of appropriately selected patients achieving at least fifty percent pain relief. Those figures depend heavily on selection — which is the entire argument for doing the diagnostic blocks first. Individual results vary.

The order of operations is the whole point

Fusion is a reasonable operation for the right problem. It is a poor operation for facet-mediated pain, because it does not address the pain generator and it permanently changes how load transfers through the adjacent levels.

The sequencing argument is straightforward: the less invasive, reversible, diagnostically-confirmed option comes first. Doing the irreversible one first, when the reversible one might have worked, is difficult to justify clinically — and, in a claim, difficult to justify economically.

The cost differential between an ablation and a cervical fusion is substantial, commonly an order of magnitude or more once facility, implant, anesthesia and rehabilitation are counted. We are not going to publish a price here, because the number depends on level count, facility and payer. But the direction is not in dispute, and it is one of the reasons this sequence matters in a personal injury context.

Why this matters for causation

Insurers routinely argue that chronic neck pain after a collision is degenerative — that the imaging shows wear the patient already had, and the crash merely coincided with it.

A diagnostic medial branch block is one of the few tools that answers that argument with something other than the patient’s own report. It is an objective, reproducible test that localizes the pain to a specific joint at a specific level. A documented, concordant response to two blocks is materially harder to dismiss than a pain diary.

That is a documentation question as much as a medical one. We wrote about the broader version of that problem in proving causation when a pre-existing condition is in play, and about the scoring systems adjusters actually use in how insurance adjusters devalue injury claims.

Frequently asked questions

How do I know whether my neck pain is coming from the facet joints?

You cannot know from imaging alone, which is the central difficulty. Facet-mediated pain typically worsens with extension and rotation — arching and turning the head — and is confirmed by a diagnostic medial branch block rather than by MRI. See what facet joint pain actually feels like for how this is worked up.

Is radiofrequency ablation permanent?

No. The treated nerves regenerate over time and pain can return, at which point the procedure can be repeated. That is a feature rather than a defect — nothing is permanently altered, and surgical options remain available. Individual results vary.

If ablation fails, have I lost the chance to have surgery?

No. Ablation forecloses nothing. This is the main reason to sequence it first. Read more on the two options injured patients are usually offered.

My insurer says the crash did not cause this. Does a block help?

It can. A concordant response to two diagnostic blocks localizes the pain to a specific joint and produces objective documentation rather than subjective report. See proving causation and exacerbation.

Where do I go for this evaluation?

Injury Experts, 4477 Woodson Rd, Suite 202, St. Louis, MO 63134, serving the St. Louis region across Missouri and Illinois. Call (314) 887-5866 or text (314) 886-5902. If your case involves a formal examination by the other side, read what an IME actually is first.

Key takeaways

• Roughly half of chronic post-collision neck pain is facet-mediated, and imaging will not show it.
• Two diagnostic medial branch blocks — not one — establish whether the facet joints are the pain generator.
• Radiofrequency ablation is outpatient, reversible, and forecloses no surgical option.
• Relief is durable but finite; the procedure can be repeated. Individual results vary.
• The same blocks that guide treatment also produce objective causation evidence.

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

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. It is not legal advice.