Emergency clinicians are tasked with the dual roles of excluding life-threatening pathology and providing effective pain relief and symptomatic care for the 2.1 million visits made to U.S. EDs each year for acute headache. (Cephalalgia. 2006;26:684.) A variety of effective medications are available for treating primary headache in the ED—NSAIDs, triptans, neuroleptics, antiepileptics, and more—but emergency physicians should also be versed in regional anesthesia techniques that are tremendously and rapidly effective. These procedures take only minutes, and can lead to swift pain relief for patients and much more rapid bed turnover compared with traditional therapies.
Sphenopalatine Ganglion Block (Image 1): A small body of literature has suggested that applying intranasal lidocaine to perform a sphenopalatine ganglion block may be effective for treating primary headache. (Headache. 1999;39:439 and 1995;35:83.) Most data are confined to case series and patients with post-dural puncture headaches (J Clin Anesth. 2016;34:194), and two randomized clinical trials with ED patients have failed to show benefit. (Ann Emerg Med. 2015;65:503; Acad Emerg Med. 2001;8:337.) Nonetheless, use of this technique continues to grow because of widely reported anecdotal success, physician with local anesthetics, and the broad safety window of lidocaine.
Some practitioners have argued for using an atomizer to instill nasal lidocaine, a useful analgesic adjunct in its own right, but this is unlikely to represent true sphenopalatine ganglion blockade, not the ganglioneuralgialytic we're searching for. The sphenopalatine ganglion itself is found in the pterygopalatine fossa, posterior to the maxillary sinus wall and directly lateral to the posterior aspect of the nasal cavity. Traditionally accessed via an infrazygomatic approach by interventional pain specialists, an intranasal technique using long cotton swabs soaked in viscous lidocaine provides technical simplicity and minimal risk.
Advance the swabs to the point of resistance (rotate laterally at the first point of resistance to maneuver more easily past the nasal turbinates) and leave them in place for 10 minutes to allow for the viscous anesthetic to find its way through the sphenopalatine foramen to the needed area. A strong argument exists for the role of the sphenopalatine ganglion in chronic migraines because common triggers such as sleep deprivation, food, olfactory stimuli, and stress activate areas of the brain that send projections and stimulation to the ganglion, ultimately causing vasodilation and release of inflammatory mediators in the meninges. The sphenopalatine ganglion receives afferent nociceptive signals from the V2 division of the trigeminal nucleus while acting as a conduit for a major portion of facial efferent fibers. (Ochsner J. 2019;19:32; http://bit.ly/2ZonXHW.)
Greater Occipital Nerve Block (Image 2): The occipital nerve block is a common therapy for cervicogenic headache and occipital neuralgia. Robust data supporting its use are lacking, but multiple open-label trials and observational cohorts, as well as clinical experience, support the technique. (Headache. 2009;49:1521; Neurotherapeutics. 2010;7:197; http://bit.ly/2MudMf3.) Classically, a landmark approach using a fan-like injection of lidocaine lateral to the occipital protuberance has been used. A better technique, however, is using ultrasound to guide proximal anesthesia at the C1-C2 level, allowing definitive treatment and taking advantage of a broader anesthetized nerve distribution.
With the patient seated, apply the ultrasound in the midline over the occiput and then move caudally to identify the C1 and C2 levels. At C2, move the transducer laterally and rotate it to bring the inferior oblique and semispinalis capitis muscles (the relevant sonoanatomy) into view. (Narouze, Samer N., Ch. 31. Atlas of Ultrasound-Guided Procedures in Interventional Pain Management, Springer, 2018.) The greater occipital nerve is well identified here, and can be easily targeted by even the most novice of ultrasonographers.
Paracervical Block (Image 3): Mellick, et al., recognizing the tremendous contribution of the cervical plexus and sensory innervation of the neck to cervicogenic and tension headache, published a retrospective review of 417 patients who received intramuscular injections of bupivacaine lateral to the sixth or seventh cervical vertebrae. Astoundingly, more than 65 percent of patients reported complete relief of their headache with this technique. No significant complications were reported. (Headache. 2006;46:1441.) The effectiveness may relate to a growing belief that the cervical plexus is a single anatomic entity that can be blocked by an injection of local anesthetic superficial to the cervical prevertebral fascia. (Reg Anesth Pain Med. 2019;44:623; http://bit.ly/2MwdwfA.)
Prepare a sterile field, and inject 1.5 mL of 0.5% bupivacaine 1-1.5 inches into the paraspinous musculature 2-3 cm bilateral to the spinous process of the sixth or seventh cervical vertebrae using a 1.5-inch 25-gauge needle. Relief is rapid and profound, and while not diagnostic of a cervicogenic component to the patient's symptoms, certainly suggestive of the same.
Regional anesthesia for primary headache is fast, effective, and simple. With limited risk and a wide therapeutic window, nerve and fascia blocks are easy to learn and forgiving of the novice. These techniques lead to rapid and remarkable pain relief, and should be part of the analgesic armamentarium of every emergency physician.
Dr. Pescatoreis the director of emergency medicine research for the Crozer-Keystone Health System in Chester, PA. He is also the host with Ali Raja, MD, of the podcast EMN Live, which focuses on hot topics in emergency medicine:http://bit.ly/EMNLive. Follow him on Twitter@Rick_Pescatore, and read his past columns athttp://bit.ly/EMN-Pescatore.