Neck Pain Months After a Car Accident: Where It Often Comes From

What this video covers

• What cadaveric and biomechanical models show happens to the cervical facet joint capsules during a rear-end collision
• Why most whiplash resolves on its own, and the point at which that stops being the right answer
• Why a normal X-ray or MRI does not rule out a real, identifiable pain source
• How diagnostic medial branch blocks confirm the joint before anything is treated, and why a negative block means no procedure
• What the sham-controlled evidence actually shows for cervical radiofrequency neurotomy, how long relief lasts, and where the evidence is still weak
• Why exercise and early movement are supported for whiplash, while ketogenic nutrition, pro-resolving mediators, and red or near-infrared light therapy remain unproven for this condition
• 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.

Neck pain that outlasts three months after a car accident often comes from a cervical facet joint. In patients referred with whiplash pain past three months, 60 percent had facet joint pain on placebo-controlled blocks. A normal X-ray or MRI does not rule it out. Diagnostic medial branch blocks test the joint before anything is treated.

You were stopped in traffic when the car behind you did not stop. They X-rayed your neck, told you nothing was broken, and sent you home. That was four months ago. You still cannot check your blind spot without turning your whole torso. Your MRI was normal. And somewhere between the third visit and the fourth, the words in your chart changed. Injury became complaint. Patient became claimant.

This article explains what the biomechanical models show happens to the neck in the first split second after a rear impact. It explains why that can cause pain that outlasts every normal image. It covers what a normal MRI does and does not rule out. And it shows how a pain source is tested instead of guessed at. It is not a pitch for a procedure. Most whiplash heals with six to twelve weeks of pain relief, early movement, graded exercise, and a return to normal activity. Inside that window no procedure is called for. A clinic offering you one is selling you something.

What happens to your neck in a rear-end collision?

Between fifty and seventy-five milliseconds after impact, your neck muscles cannot yet brace. The seat drives your torso forward while your head stays behind. The neck briefly takes an S-shape. The lower levels bend back while the upper levels are still bent forward. Only after about a hundred and fifty milliseconds does the neck swing into simple extension. That is the motion most people picture when they hear the word whiplash.

In those models, the early S-shape, not the later swing, loads the paired zygapophysial joints, the facet joints. These are the small paired joints at the back of each spinal level, about the size of a fingernail. They let your neck turn and tilt back. Each one is wrapped in a capsule.

Here the evidence has to be labeled honestly. Cadaver and computer models show the capsule stretching past its normal range in that S-curve window. That is enough for what the research calls sub-failure injury, at crash speeds people survive without breaking a bone. Sub-failure is the exact word. The tissue is loaded past the point of damage, without tearing through. That mechanism is modeled, not measured in you. The spinal cord sensitization often cited with it comes from rodent work. Lab guesses should not be dressed up as bedside proof, and we are not dressing them up here.

Where does neck pain come from months after a car accident?

No one has shown in living patients that this modeled capsule loading causes any one person’s pain. No scan settles it. What we can describe is the pattern that makes the facet joint worth testing. The pain sits deep in the center of the neck instead of shooting down the arm. It gets worse when you tilt back or turn, which is why the blind-spot check gives you away. And it is tender to press over the articular pillars. That is the bony column you can feel a couple of finger-widths to either side of the middle at the back of your neck.

That pattern is a reason to test, not proof of a mechanism. And none of it shows up on film. A joint capsule sending pain signals is not a structural finding. It is a functional one, and functional questions need functional tests.

What has been measured, in living patients, is how often this joint turns out to be the source. In 1996, in Spine, Lord and colleagues studied sixty-eight patients in a row who were referred with neck pain lasting beyond three months after whiplash. They used comparative and placebo-controlled numbing blocks. Sixty percent had cervical facet joint pain (95% confidence interval 46 to 73 percent). That figure has limits, stated plainly. It is the yield in a referred population that had already failed to recover. In that group, patients whose main problem was headache were screened first at the C2-3 level. It is not the rate for everyone in a collision. It is not a pure axial (center-of-the-neck) pain number either.

Why does whiplash pain get missed when the MRI is normal?

Standard early care for whiplash is mostly right. Pain relief, early movement, and graded exercise are what most people need, and most get better on them. The failure is not in the first six weeks. It is at month four, when the assembly line offers two exits. Neither one has a diagnosis behind it.

Behind the first door: the images are normal, so the injury healed, so what is left must be stress, a lawsuit, or catastrophizing. Behind the second: one shot after another, picked by body region, not by diagnosis. A trigger point here, a steroid there, because the neck is where the needle goes.

Both doors share the same flaw. Nobody made a diagnosis.

A normal MRI does not tell you your neck is fine. It tells you there is no tumor, no cord compression, no disc on a nerve root, and no major ligament tear. It is also not the test that rules out a non-displaced fracture (a break that has not shifted). That is a CT. If nobody ordered one, that should be said out loud.

Corticosteroid is not used at all in radiofrequency neurotomy, described below. This is educational information only. Do not start, stop, or change any medication without consulting your physician.

How is lasting neck pain after a car accident diagnosed and treated?

First, close the differential

Two things come off the list before anything else, because they are what hurt people.

• Cervical artery dissection. Sudden severe neck or back-of-head pain after a crash, with dizziness, vision change, drooping, or slurred speech, is a dissection (a torn artery) until a CT or MR angiogram says otherwise. That means the emergency department, not a pain clinic.
• Concussion. Ongoing headache, fogginess, light sensitivity, or trouble holding a thought is a brain injury. It is managed on its own track. No needle in your neck fixes it.

Then the rest of the list. Arm pain that shoots down, with weakness or reflex loss, is radiculopathy. Walking changes, clumsy hands, and overactive reflexes suggest myelopathy (spinal cord squeeze), which is urgent. Hidden fracture and an unstable skull-to-neck joint must be ruled out first.

Say what remains is pain in the center of the neck. It is worse when you tilt back or turn, tender over the articular pillars, with no neurologic deficit (nerve loss), past three months. Then the facet joint becomes a testable hypothesis. That is not the same as a diagnosis, and the difference is the whole point.

Then test it, with blocks that can fail

From C3-4 down, each cervical facet joint gets its nerve supply from two medial branches, one above and one below. They wrap around the waist of the articular pillar. Under live fluoroscopy (real-time X-ray), we can reach those nerves with a tiny amount of local anesthetic. If that joint is the source, your pain stops for as long as the drug lasts. It comes back when the drug wears off.

C2-3 is the exception. It is supplied by the third occipital nerve. That nerve crosses the back of the joint itself, not a pillar waist. So it is blocked and treated differently. It also carries its own risk of short-term unsteadiness.

One positive block is not enough. Single blocks give too many false positives. The standard is dual comparative blocks. A short-acting numbing drug on one visit, a long-acting one on another, and your relief has to match the drug. Longer relief with the longer-acting drug is a matching (concordant) result.

And the sentence that costs a practice money: a negative block means no procedure. If the joint does not answer, we do not burn it. Want the step-by-step detail? What the visits look like, and what is and is not done at each step, is laid out on the car accident injuries treatment page.

Only then, neurotomy — and only with the numbers on the table

When both blocks match and are positive, radiofrequency medial branch neurotomy becomes an option. Under fluoroscopic (live X-ray) guidance, the electrode is laid parallel to each medial branch. Parallel, because the burn forms along the shaft of the active tip, not across it. The tissue is heated to about eighty degrees Celsius. That cooks the nerve carrying the joint’s pain signals. It shuts off the signal. It does not repair anything. Anyone calling it healing is not describing this procedure.

The evidence, and its limits:

• Effect size (established, small trial). In the New England Journal of Medicine, also in 1996, Lord randomized twenty-four patients with central neck facet pain after a crash. They got real neurotomy or a true sham. The procedure was identical, but the current was never switched on. Patient and assessor were both blinded: neither knew which was which. Median time for pain to return to half of baseline: 263 days treated versus 8 days sham (P=0.04). Seven of twelve versus one of twelve were pain-free at twenty-seven weeks. Twenty-four patients is a small trial, and it should be read as one.
• Durability and grade (established, with a stated conflict). In 2016, in Pain Medicine, Engel and the Standards Division of the International Spine Intervention Society pooled the published data. Most patients were pain-free at six months, and more than a third at one year. The number needed to treat was two for complete relief at six months. Those are pooled figures from a systematic review of what has been published. They are not the result of a second sham-controlled trial. The authors graded effectiveness high quality, but only on one condition. The grade holds when the procedure meets their own society’s technical standard. They graded the evidence on risks low quality. We report both grades because they published both. And it is worth knowing that the group that wrote the standard is the group that graded compliance with it.
• Scope (contested where it is stretched). The controlled evidence above comes from axial neck pain, not headache. It should not be stretched there.

A number needed to treat of two means about half of correctly chosen patients do not get complete relief. Individual results vary.

The real risks, stated flatly. Numbness in the treated area. Post-neurotomy neuritis (nerve irritation) that can burn for weeks. Short-term unsteadiness after third occipital neurotomy. Weakness in the deep muscles along the spine. New or increased pain. Bleeding. Infection. And, rarely, nerve injury. The systematic review graded the evidence on these risks low quality. So the honest answer about how often they happen is that no one knows exactly.

It is also not permanent. Nerves outside the brain and spinal cord grow back. Relief usually ends between six and eighteen months, and repeat treatment is expected. If nobody told you that, you were not consented. You were recruited. Movement and retraining the deep front neck muscles are what hold the result.

About the adjuncts you may have been offered

You may have been offered a ketogenic protocol, an omega-3 pro-resolving mediator, or red-light therapy for this neck. For whiplash, all three rest on cell-culture and rodent work. No controlled trial has shown that any of them shortens a whiplash-associated disorder or helps a facet-driven neck. They are adjuncts under study, not treatment for what happened in that collision.

What a real course can look like

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

Five months after a rear-end collision. Central right-sided neck pain, worse when tilting back or turning. No arm symptoms, normal exam, normal MRI. Comparative blocks followed. A short-acting drug gave a little over an hour of near-complete relief. Weeks later, a long-acting drug gave most of a day. Longer relief with the longer-acting drug. Concordant. Only then was neurotomy discussed.

The hard parts are the ones nobody advertises. Insurance approval took weeks. The first two weeks after were worse, not better. Burning, patchy numbness, neuritis, and a message asking whether the nerve was damaged for good. Relief settled in during weeks three and four. Around ten months the ache came back as the nerves regrew, just as predicted.

That is a good outcome. It is not everyone’s outcome. Individual results vary.

Frequently asked questions

Key takeaways

• In the first 50-75 milliseconds of a rear impact, the neck forms a brief S-curve that loads the facet joint capsules. Cadaver and computer models show this. It has not been measured in living patients.
• In patients referred with neck pain lasting beyond three months after whiplash, 60% (95% CI 46-73%) had cervical facet joint pain on comparative and placebo-controlled blocks. That figure comes from referred patients. It is not a rate for everyone in a collision.
• A normal MRI rules out several serious structural problems. It cannot confirm or rule out a facet joint as the pain source. Only a diagnostic block can, and a negative block means no procedure.
• The sham-controlled evidence cited here comes from a twenty-four-patient trial in central neck pain, not headache. It should not be stretched to headache. The systematic review that grades effectiveness high quality grades the risk evidence low quality.
• About half of correctly chosen patients do not get complete relief. Relief usually ends in six to eighteen months as the nerves regrow, and repeat treatment is expected.
• If your neck pain has outlasted three months since your collision, the next step is not another injection. It is a diagnosis.

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. To be evaluated, call (314) 481-5000 or text (314) 886-5902 — bring your imaging and your timeline.

References

1. Lord SM, Barnsley L, Wallis BJ, McDonald GJ, Bogduk N. Percutaneous radio-frequency neurotomy for chronic cervical zygapophyseal-joint pain. N Engl J Med. 1996;335:1721-6. PMID 8929263. PubMed
2. Lord SM, Barnsley L, Wallis BJ, Bogduk N. Chronic cervical zygapophysial joint pain after whiplash. A placebo-controlled prevalence study. Spine (Phila Pa 1976). 1996;21:1737-44. PMID 8855458. PubMed
3. Engel A, Rappard G, King W, Kennedy DJ; Standards Division of the International Spine Intervention Society. The Effectiveness and Risks of Fluoroscopically-Guided Cervical Medial Branch Thermal Radiofrequency Neurotomy: A Systematic Review with Comprehensive Analysis of the Published Data. Pain Med. 2016;17:658-69. PMID 26359589. 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