Numbing the suspect
A small amount of local anaesthetic is placed precisely into the facet joint. If your usual pain fades while the area is numb, that joint is implicated.
Diagnostics · Invasive
Diagnostic Facet Joint Injection
A targeted injection into a facet joint to help determine whether that joint is a source of pain.
What it is
Ask the joint directly
Facet joints rarely show their guilt on scans — worn-looking joints are often painless, and painful ones can look normal. A diagnostic injection bypasses the guesswork: numb the suspect joint under imaging guidance, and your pain response delivers the verdict.
Image-guided precision
Fluoroscopy or CT guidance confirms the needle sits inside the joint — sometimes with a trace of contrast — so a negative result is meaningful, not a miss.
Temporary by design
The numbness lasts only hours. This test diagnoses; it does not treat. Lasting relief, if the joint is confirmed, comes from the treatment planned next.
One level at a time
Joints are tested selectively so each answer points to a specific level rather than blurring across the spine.
Invasive diagnostics are used only when the result will change the plan. Suitability is assessed individually.
Common questions
Things patients ask us
How is this different from a medial branch block?
Both test facet-mediated pain. The injection numbs inside the joint itself; the block numbs the small nerves supplying it. Your surgeon chooses based on what needs proving.
Will it hurt?
The skin is numbed first and the needle is thin. Most people feel pressure rather than pain, and the whole test is brief.
What must I disclose beforehand?
Blood thinners, diabetes, infections, allergies and pregnancy all matter. Bring a full medication list so the team can plan safely.
What happens after a positive result?
The team explains which treatments address a confirmed facet source — which may include radiofrequency treatment of the supplying nerves — and what each involves.
Start with your case.
Send your history and any imaging you already have. The ProSpine team will review your case and respond with the next steps.
Free · No obligation · Reviewed by the ProSpine team