- There is medium quality evidence from a single randomised controlled trial (RCT) that third occipital nerve blocks have diagnostic utility for the diagnosis of cervical headache in adults following whiplash injury.
- The RCT reported that, among patients with headache following whiplash, prevalence of third occipital nerve-related headache was 38%. A diagnosis of third occipital nerve headache was more likely if headache was the predominant complaint and there was tenderness over the C2/C3 zygapophyseal (z- or facet) joint on the side of the pain.
- 71 patients enrolled in the RCT but only 55 (77%) completed both sets of diagnostic blocks.
Third occipital nerve blocks may be used in the investigation of cervical headache following whiplash in adults. Double-blind, comparative blocks should be used as there is a high false-positive rate associated with single diagnostic blocks (C).
The third occipital nerve provides the C2/C3 z-joint (one of the joints in the upper cervical spine) with sensation. The intervention is performed when there is suspicion that this joint is the source of a patient’s pain.
The typical patient will have persisting upper neck pain and headaches following a whiplash injury sustained in a motor vehicle accident.
- Diagnosis of third occipital nerve headache.
A fine needle is carefully inserted into the side of the neck and is placed close to the C2/C3 joint under x-ray guidance. Three injections, each of 0.3ml of local anaesthetic, are placed at specific target points to cover the likely course of the nerve. Temporary, but complete, relief of pain will result if the C2/C3 joint is the source of the patient’s pain.
The procedure is performed in a facility such as a radiology suite or operating theatre where there is access to a C-arm fluoroscope.
Third occipital nerve blocks are performed by doctors with appropriate training in the conduct of the procedure. In the New Zealand setting this would most likely be a musculoskeletal physician, anaesthetist or radiologist. The assistance of a radiographer is required during the procedure. Afterwards an independent assessor, such as a registered nurse, would usually monitor the effect of the block for up to two hours.
One medium to high quality experimental study provided information on the effectiveness of this procedure in diagnosing third occipital nerve headache following whiplash (Lord et al. 1994). Among patients with headache after whiplash, the prevalence of third occipital nerve headache was 38%. Patients were more likely to have third occipital nerve headache if their headache was the predominant complaint (as opposed to neck pain) and there was tenderness of the C2/C3 z-joint on the side of the pain. The authors concluded that controlled diagnostic blocks were still the definitive method of establishing the diagnosis of third occipital nerve headache.
The study described above contained no discussion of adverse effects or complications related to blockade of the third occipital nerve. No other references pertaining to safety, side effects or complications of third occipital nerve blockade were found.