What is Occipital Nerve Block?

Essentially an Occipital Nerve block is numbing of the greater and lesser occipital nerve. The block is an injection composed of an anesthetic and a corticosteroid next to the greater and lesser occipital nerves, which are located just beneath the scalp, superficial to the skull, in the back of the head. It is most often used in the diagnosis and treatment of Occipital Neuralgia and Cervicogenic headache (Afridi 2006). Occipital Neuralgia will typically follow a trauma to the nerves over the occiput (back of the head) and is characterized by an acute onset of pain in the distribution of the occipital nerves.

Cervicogenic headache is more chronic, with an insidious onset, characterized by pain in the same distribution. Most patients with Cervicogenic headaches have associated spondylosis or problems of the cervical facet joints in the neck and therefore may need an additional block in the cervical facet joint to completely alleviate their symptoms.

A group of people suffering from Cervicogenic headaches was split into two categories, one of which received the Occipital Nerve Block. The study found that analgesic consumption, duration of headache and its frequency, nausea and vomiting, photophobia (fear of light), phonophobia (fear of noise), decreased appetite, and limitations in functional activities were significantly less in the blocked group compared to control group. The study therefore concluded “the nerve stimulator-guided occipital nerve blockade significantly relieved cervicogenic headache and associated symptoms at two weeks following injection.” (Naja 2006)

The greater occipital nerve arises from the second cervical nerve root and travels deep to the cervical paraspinous musculature and becomes superficial just below the superior nuchal line and lateral to the occipital protuberance of the skull, just lateral to the occipital artery. The lesser occipital nerve is a terminal branch of the superficial cervical plexus and arises from the second and third cervical nerve roots. It then travels through the cervical paraspinous musculature and become superficial over the inferior nuchal line of the skull. The lateral section of the posterior scalp is supplied by the lesser occipital and great auricular nerves. These nerves are commonly involved in patients suffering from Cervicogenic headaches and Occipital Neuralgia.

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 brain1, 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 characteristics4, 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 inflammation1, 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 solution2, 3.

The procedure involves inserting a small fine needle through the skin beneath the scalp in order to get the anesthetic and corticosteroids around the area of the nerve. In order to minimize this discomfort your pain specialist may numb the skin in the injection area with an even smaller needle with a local anesthetic before inserting the block needle. The injection blocks both the greater and lesser occipital nerves. There are two major benefits to using this block. Not only is it useful in treating Occipital Neuralgia, relieving or reducing pain in the back of the head in the scalp, but if symptoms improve after the injection then the block is also useful in diagnosing Occipital Neuralgia. Typically if you respond well to the injection and have pain relief then it is recommended that you return and receive repeat injections.

Usually, a series of block injections is needed to treat the problem adequately, however the response to the block varies from patient to patient. Also, if you respond well to the Occipital Nerve block then you will most likely benefit even more with the addition of Occipital Nerve Stimulation. A 2006 study reported that if a patient receives repeated nerve stimulator guided Occipital Nerve blockade for the treatment of Cervicogenic headache, the patients experienced significant reduction of symptoms with no recurrence for at least six months in addition to alleviation of associated symptoms. Eighty-seven (87%) of the patients who experienced relief required more than one injection to achieve a six-month period of pain relief (Naja 2006).

Risks

Occipital Nerve Block injections are considered safe, however, with every procedure there are associated risks, side effects, and possible complications. With nerve blocks in general, the most common is the superficial pain from the scalp where the needle was inserted. This pain comes after the local anesthetic wears off, but this pain is temporary and typically mild. Another frequently seen occurrence is bleeding, since the scalp is highly vascular (there is an abundance of tiny blood vessels near the surface of the skin). Bleeding is common but is easily stopped and temporary. This risk is significantly reduced if ice is placed at the injection site immediately after the procedure. The other less common risks involve excessive bleeding, infection, and nerve damage. Patients with an allergy to any of the anesthetics used, are on blood thinning medications, have an active infection, or are pregnant should consult with your pain physician before receiving the procedure.

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.
  7. Occipital nerve blockade for cervicogenic headache: a double-blind randomized controlled clinical trial Naja ZM, El-Rajab M, Al-Tannir MA, Ziade FM, Tawfik OM. Pain Pract. 2006 Jun;6(2):89-95 PMID: 17309715
  8. Repetitive occipital nerve blockade for cervicogenic headache: expanded case report of 47 adults. Naja ZM, El-Rajab M, Al-Tannir MA, Ziade FM, Tawfik OM. : Pain Pract. 2006 Dec;6(4):278-84 PMID: 17129309
  9. Greater occipital nerve injection in primary headache syndromes–prolonged effects from a single injection Afridi SK, Shields KG, Bhola R, Goadsby PJ. Pain. 2006 May;122(1-2):126-9. Epub 2006 Mar 9 PMID: 16527404 Textbooks: Atlas of Interventional Pain Management Author(s): Waldman, Steven D. Pub. Date: 7/1/1998 Publisher (s): Elsevier Science Health Science division.