Occipital Nerve Block

• Pain in the distribution of the greater or lesser occipital nerves
• Stabbing quality pain that occurs in paroxysms, which may ache between paroxysms
• Tenderness on palpation along the affected nerve
• Positive response to local anesthetic

Patients complain of a shooting or stabbing pain in the neck radiating over the cranium. Constant pain can persist between the paroxysms. The pain can be perceived in the retro-orbital area caused by overlap of the C2 dorsal root and the trigeminal nucleus. Vision impairment/ocular pain (67%), tinnitus (33%), dizziness (50%), nausea (50%), and congested nose (17%) can be present because of connections with cranial nerves VIII, IX, and X, and the sympathetic trunk.

Occipital nerve block

This involves injection of local anaesthetic and steroid around the occipital nerve. The procedure is performed under real time ultrasound guidance for greater accuracy and safety.

Occipital nerve block can be of diagnostic as well as therapeutic benefit. Patients who get a positive response from occipital nerve blocks should be offered pulsed radiofrequency treatment for a more sustained response.

Technique

The procedure is usually done on an outpatient basis. The procedure is performed under ultrasound guidance to ensure accuracy of needle placement. Patients should be aware that the outcome of the procedure is variable and they may not receive the desired benefits. Similarly, they must be aware of the transient nature of the therapeutic benefits and that there may need repeated injections.

Generally a mixture of local anaesthetic and steroid is injected. The anaesthetic is responsible for immediate pain relief, whereas steroids tend to provide pain relief 2–6 days after their administration.

Pulsed radiofrequency ablation of occipital nerve (PRFL treatment)

Pulsed radiofrequency treatment of the occipital nerve involves application of short pulses of radiofrequency signals from a radiofrequency generator to the occipital nerve. The procedure is performed under local anaesthetic, using real time ultrasound guidance for accurate positioning of the needle. A small amount of electric current is passed prior to lesioning of the nerve to confirm the needle position.

Generally local anaesthetic is injected around the nerve following nerve ablation. The local anaesthetic is responsible for immediate pain relief, where as pulsed radiofrequency takes 4 to 6 weeks to provided sustained pain relief.

Complications are rare, particularly if the injections are performed using a precise needle-positioning technique. Possible complications include bruising, infection, hematoma, nerve injury and reaction to the injectates. Infection can be avoided with appropriate aseptic precautions. Severe allergic reactions to local anaesthetics are uncommon. Steroid injections may produce local reactions, occurring most often immediately after injection. These local reactions last for 24 to 48 hours, and are relieved by application of ice packs. Post-procedural pain flare-up may occasionally occur, and may be treated with painkillers. Neurological complications including paraesthesias and numbness have been described but are rare.