Occipital Nerve Block

Written by Staff | 30 October 2011

Interventional nerve blocks have become an important therapy in the treatment of certain types of acute and chronic pain, particularly where management with medications is unsuccessful. With nerve blocks, medication consisting of an anesthetic and a steroid is injected directly into a nerve to reduce inflammation and block the transmission of pain signals to the brain¹.

An occipital nerve block (ONB) specifically blocks the occipital nerve, a carrier of pain signals from the head and neck to the brain^{1, 3}. ONB’s can be used to treat several conditions:

• Occipital neuralgia is a condition which leads to headaches in the occipital region at the back of the head where the skull meets the neck. It is a neuropathic pain that typically manifests as an intermittent, brief episode of shocking pain around the back of the head³. The cause of occipital neuralgia is uncertain, but it often develops spontaneously. They can also occur with whiplash injuries or other impacts to the back of the head. Headaches may occur intermittently throughout the week, and have been known to lead to nausea and vomiting. Because of the similarity of symptoms, occipital neuralgias are commonly confused with migraines³. Local ONB is the treatment of choice for occipital neuralgias. In one study, an ONB provided headache relief for 90% of patients, lasting an average of 28 days¹
• Trigeminal autonomic cephalagias are a group of headache disorders that preset with similar characteristics^{4, 5, 6}. These headaches tend to be severe and affect only one side of the head, while presenting with symptoms of the autonomic nervous system malfunction including sweating, flushing, tearing and a runny nose on the affected side. Trigeminal autonomic cephalagias include cluster headaches, paroxysmal hemicrania headaches, and SUNCT (short-lasting uniform neuralgiform headache attacks with conjunctival injection) and SUNA (short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms)^{4, 5, 6}. Despite their similarities, each of these headache types differs in duration, frequency and response to therapy⁶. However, each type of headache, especially when chronic and unresponsive to medication treatment, may benefit from ONB⁴

The Procedure

Of the nerve blocks, the ONB is one of the easiest and safest to perform. During the procedure, and neurologist or interventional pain specialist will feel for the protrusion of the occipital bone of the skull behind the ear, and identify the pulsing, nearby occipital artery which runs alongside the greater occipital nerve¹. The physician can then inject an anesthetic/steroid solution into the area to provide pain relief and reduce inflammation^{1, 2}. A lesser occipital nerve can also be targeted by injecting an area just below and to the outside of the greater occipital nerve².

ONB has very few complications when performed by a trained physician. The primary complication is inadvertent injection into the occipital artery which can cause a number of systemic symptoms, including diffuse numbness of an area, dizziness or an allergic reaction. This is easily avoided by suctioning the syringe and checking for blood before injecting the solution^{2, 3}.

References

1. Zhou, Y. (2008). Principles of Pain Management. Bradley: Neurology in Clinical Practice, 5th Ed. MD Consult Web site, Core Collection.
2. Amsterdam, J., Kilgore, K. (2009). Regional Anesthesia of the Head and Neck. Bradley: Roberts: Clinical Procedures in Emergency Medicine, 5th Ed. MD Consult Web site, Core Collection.
3. Garza, I. (2010). Occipital neuralgia. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA.
4. May, A. (2010). Cluster headache: Epidemiology, clinical features and diagnosis. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA.
5. Matharu, M. (2011). SUNCT and SUNA headache syndromes: Treatment. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA.
6. Matharu, M.; Cohen, A. (2009). Paroxysmal hemicranias: Clinical features and diagnosis. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA.