M2E Too! Mellick's Multimedia EduBlog
The M2E Too! Blog by Larry Mellick, MD, presents important clinical pearls using multimedia.

By its name, M2E Too! acknowledges that it is one of many emergency medicine blogs, but we hope this will serve as a creative commons for emergency physicians.

Tuesday, October 2, 2012

Another Arrow for Your Headache Quiver: Cervical Injections

People don’t come to the emergency department for treatment of headaches unless their headache severity or duration is intolerable or the headache is frighteningly different. (Neurol Clin 1998 May;16[2]:285.) Usually, these headaches have failed to respond to their usual and standard therapies. In fact, those who market the migraine-specific triptan drugs recognize that headaches that have progressed to the state of central sensitization simply don’t respond well to their drugs. (Ann Neurol 2004;55[1]:27; Ann Neurol 2004;55[1]:19; Clin Ther 2000;22[9]:1035.)

Central sensitization is an increased response to stimulation that is mediated by amplification of signaling in the central nervous system. It is primarily demonstrated by allodynia, a painful response to a stimulus that does not normally cause pain. (Clin Ther 2000;22[9]:1035; Funct Neurol 2000;15[Suppl 3]:28; Ann Neurol 2000;47[5]:614.)

In other words, headaches in the emergency department are not your garden-variety headaches. We are dealt the most difficult headaches to treat and need as many therapeutic arrows in our quiver as possible.

The injection of small amounts of 0.5% bupivacaine bilaterally in the paraspinous muscles at the C6 or C7 level of the posterior neck was first recognized in 1996, and the first case series was published in 2003. It also appears to have a role in managing orofacial pain. (Headache 2003;43[10]:1109.) A 1.5-inch 25-gauge needle is used to inject 1.5 mL of 0.5% bupivacaine HCl approximately 1-1.5 inches into the paraspinous musculature 2-3 cm bilateral to the spinous process of the sixth or seventh cervical vertebrae. The entire amount is completely deposited in a single injection location. Videos are one of the most effective ways to teach procedures, and this one is no exception. (Click the link below to watch the video demonstrating the procedure.)

The science behind this procedure currently is several case series and one large retrospective review of 417 patients. (Headache 2006;46[9]:1441; www.ncbi.nlm.nih.gov/pubmed/17040341.) Jerome Hoffman, MD, and Richard Bukata, MD, reviewing the article in Emergency Medicine Abstracts called the methods “pristine.” (http://bit.ly/OBj99l) The article was subsequently touted as one of the best articles of the year.

Two other retrospective review articles with fewer patients describes the benefit of this technique for treating headaches in children and orofacial pain. (Pediatr Emerg Care 2010;26[3]:192; J Orofac Pain 2008;22[1]:57.) No prospective studies have been published, but clinical experience with this procedure is growing.

How effective is this procedure? I am confident that it is not as effective as intravenous prochlorperazine (Compazine) and diphenhydramine, but it is equal to or better than most of the other therapeutic options currently used. Approximately 65 percent of patients get compete relief, and another 20 percent get partial relief. Overall 85 percent of patients receive benefit from this procedure. (Headache 2006;46[9]:1441.) An important reality is that bad headaches are often difficult to manage. Consequently, some patients require three or four therapeutic arrows from our quiver for treating migraine headaches. The cervical injection is often successful as a rescue medication for other failed interventions, but a Plan B is sometimes needed for failed or partial responses to cervical injections.

What are the drawbacks of this procedure? The first is convincing the emergency physician that the procedure is safe. Something about sticking needles into the back of the neck unnerves physicians. I have been fascinated by the reticence demonstrated by emergency medicine residents and attending physicians to perform this simple procedure. The same physicians who wouldn’t blink an eye at inserting a central line or plunging a chest tube into someone’s thorax are often hesitant about performing a cervical injection. The good news is that anatomically there is nothing but muscle at these injection sites. Muscle soreness the next day is often reported by the patient. Explaining that there may be muscle pain similar to an influenza shot is understandable to the patient. The other downside is that patients who are especially averse to needles may reject the procedure, but most patients with severe headache will allow you to do anything to feel better.

What are the benefits of the procedure? First, it is fast. Injections that successfully relieve headache pain often do so in five to 15 minutes. One can quickly move to plan B if the patient does not respond by 20 minutes. Other than the nursing staff delivering the bottle of bupivacaine out of the dispensing device, it does not require much ancillary support. It is possible to have the patient feeling better and discharged before the registration clerk has finished her job.
How long does the benefit last? Our experience has shown the benefit usually lasting until the next headache. On the other hand, the headache may return within hours to days if the inciting cause of the headache persists (toothache, nitroglycerin, viral meningitis, etc.). The bilateral paraspinous cervical injection with small amounts of bupivacaine in the lower neck is another excellent option for managing those extremely tough headache cases we typically encounter in the emergency department. Try it!

Watch a video demonstrating the injection of bupivacaine into the paraspinous muscles.