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OJAI, CA—Peripheral nerve blocks are a reasonable therapeutic option for many patients with headache disorders, according to an overview provided at the Ninth Annual Headache Cooperative of the Pacific Winter Conference. Cluster headache is the indication for which nerve blocks have the best evidence. The data are mixed for other disorders, such as migraine.
“Therapeutic injections for headache can be performed effectively, safely, and efficiently after gaining a basic understanding of the literature and anatomic landmarks,” said Jack Schim, MD, Codirector of the Headache Center of Southern California and Chief of Neurology at Scripps Hospital in Encinitas.
Jack Schim, MD
A survey of members of the American Headache Society published in 2010 found that headache practitioners commonly use nerve blocks, but dosing regimens and the use of corticosteroids vary greatly. Neurologists most often use nerve blocks to treat occipital neuralgia and chronic migraine, although they also use nerve blocks for tension-type headache, hemicrania continua, and other disorders.
“Anesthetic blocks get the patients better pretty rapidly,” Dr. Schim said. “You do a nerve block … and they say, ‘Oh, my headache’s gone. How long is it going to feel good?’ That is the gratification to both us and the patient.”
A Two-Minute Procedure
Performing nerve blocks typically takes a few minutes. Some neurologists may choose the injection site based on the location of pain. Dr. Schim injects all of the potential targets—the auriculotemporal, zygomaticotemporal, supratochlear, supraorbital, and greater and lesser occipital nerves when treating migraine. For cluster headache, paroxysmal hemicrania, or hemicrania continua, he may block just the ipsilateral occipital nerve. If there is not sufficient pain relief, he may then block the trigeminal branches. “Local pain may not be the primary determinant of where we ought to inject,” he said. “Think about the usual cluster patient who has V1 orbital pain, and yet occipital block with steroids … can be very effective in transitional pain relief.”
Neurologists mainly inject lidocaine (concentration, 1–2%; maximum dose, 300 mg) or bupivacaine (concentration, 0.25–0.5%; maximum dose, 175 mg), and some neurologists inject both drugs. The effect of lidocaine lasts for one to three hours, whereas the effect of bupivacaine lasts for four to eight hours. Dr. Schim typically uses bupivacaine alone and finds that patients become numb in a couple of minutes.
Pain relief commonly lasts longer than the anesthetic effect. Virtually all patients seem to experience pain relief after receiving nerve blocks, but there is no way to predict whose headaches will return the next day or which patients will experience weeks of relief, Dr. Schim said.
Who Might Benefit
Nerve blocks may rescue patients who have failed their home medications. They also may be used to treat patients who need relief between onabotulinum toxin A injections. For example, in a patient who has good results for 10 weeks after receiving onabotulinum toxin A, a nerve block may provide relief during the two weeks until his or her next onabotulinum toxin A injection. Nerve blocks also may help to wean patients with medication overuse headache from their acute therapy. “If we get them to stop their acute medicine, things are going to get worse for a while. One of the options is to bring them in for blocks at whatever frequency you feel comfortable with,” he said.
Nerve blocks also may be appropriate for children and pregnant patients. In pregnancy, lidocaine is considered a category B drug. “It’s a reasonable migraine prophylaxis if it works for someone,” he said. “I have some patients who came in every two to three weeks, and that successfully got them through pregnancy.” Receiving nerve blocks with greater frequency might be uncomfortable for patients because the procedure usually is painful until the onset of numbness.
In 2014, Govindappagari et al published a case series of 13 pregnant women with migraine who received peripheral nerve blocks for status migrainosus or short-term prophylaxis of frequent headache attacks. In status migrainosus, average pain-score reduction was 4.0 immediately and at 24 hours after the procedure. For short-term prophylaxis, average immediate pain-score reduction was 3.0. The two patients who did not receive any acute pain reduction from the nerve blocks developed preeclampsia, and their headaches resolved post partum.
A 2014 study by Gelfand et al examined the efficacy of greater occipital nerve injections in 46 children with chronic primary headache disorders. They found that injections of lidocaine and methylprednisolone acetate benefited 53% of patients, including 62% of those with chronic migraine and 33% of those with new daily persistent headache. “In children, we have very few on-label options and we certainly have little kids who could benefit from some relief,” Dr. Schim said.