What is a Diagnostic Cervical Facet Joint Nerve Block?

A diagnostic cervical facet joint nerve block is an injection used to determine whether your chronic neck pain is originating from the small joints at the back of the cervical spine, called facet joints. This is done by injecting local anaesthetic near the medial branch nerves that
carry pain signals from these joints. If your pain improves significantly following the injection, it suggests the facet joints are the likely source of your symptoms.

What conditions do we offer this for?

We may offer this procedure for patients with:

  • Chronic neck pain suspected to arise from cervical facet joints
  • Cervicogenic headache (headache arising from the spine)
  • Neck stiffness or aching, particularly worsened by turning, tilting, or extending the neck
  • Pain not responding to medication or physiotherapy
  • To evaluate the suitability for radiofrequency denervation of the cervical medial branch nerves

Why is it done?

The injection is performed to:

  • Help confirm if the facet joints are the source of your neck pain
  • Support diagnosis when imaging (e.g., MRI) does not clearly identify the pain source
  • Guide further treatment, including radiofrequency denervation
  • Provide temporary pain relief to facilitate further physical therapy or movement assessment

What does the procedure involve?

  • You will lie on your side with your head supported.
  • The skin over your neck is cleaned and numbed with a local anaesthetic.
  • Under X-ray or ultrasound guidance, fine needles are positioned near the medial branch nerves of the suspected facet joints.
  • A small amount of local anaesthetic only is injected (no steroid).
  • The procedure takes around 15–30 minutes and is carried out as a day case.
  • You will be asked to assess your pain levels during activities in the hours following the procedure.

Benefits

  • Helps confirm the cause of your neck pain
  • Can guide further treatment decisions, such as radiofrequency denervation
  • Minimally invasive and quick
  • Temporary relief may improve function and provide diagnostic clarity

Side Effects

Very Common side effects

(may affect more than 1in 10 patients):
  • Pain or bruising at the injection site
  • Mild temporary numbness or stiffness in the neck
  • Temporary increase in pain before improvement

Common side effects

(may affect up to 1in 10 patients):
  • Localised swelling or discomfort
  • Light-headedness or dizziness

 Rare side effects

(may affect up to 1 in 1,000 patients):
  • Infection at the injection site
  • Temporary weakness or altered sensation in the arm or shoulder

 Rare side effects

(may affect up to 1 in 1,000 patients):
  • Nerve injury or prolonged numbness
  • Bleeding or haematoma
  • Allergic reaction to local anaesthetic
  • Lung puncture (pneumothorax) — rare but possible due to proximity to the lungs

Aftercare Advice

  • You will be monitored after the injection and usually discharged the same day.
  • Avoid driving for 24 hours.
  • Monitor and record your pain levels over the next 6–12 hours, especially during normal movements.
  • Resume daily activities gradually.
  • A follow-up appointment may be arranged to discuss results or to plan further treatment if appropriate.

When to Seek Medical Attention

Please attend A&E immediately if you experience:
• Fever, chills, or signs of infection at the injection site
• Sudden chest pain, breathlessness, or dry cough
• New or worsening arm numbness or weakness
• Loss of bladder or bowel control
• Severe or ongoing neck pain not relieved by usual medication