The Sphenopalatine Ganglion’s Role In Therapeutic Approaches to Trigeminal Autonomic Cephalgias (TCA).

The Sphenopalatine Ganglion Block (SPG) has over 100 year history of safely and effectively treating a wide spectrum of headaches, migraines TACs as well pain everywhere in the head and neck regions particularly those associated with the eyes, jaws, nose, ear and sinus regions.

There are four unique types of primary headaches that are considered to be Trigeminal Autonomic Cephalgias (TAC). These include Cluster Headache (CH) which is the most common type, Paroxysmal hemicrania (PH) which is often identified by sensitivity to indomethacin compared to Cluster Headache, Hemicrania Continua (HC) identified by strictly unilateral pain though there are reports of bilateral pain, and SUNCT or Short-lasting Unilateral Neuralgiaform headache with Conjunctival injection and Tearing/ SUNA or Short-lasting Unilateral Neuralgiaform headache with cranial Autonomic symptoms.

There are many shared clinical features which due to the common underlying activation of the Trigeminal-autonomic reflex. Targeted treatment is often used for patients who are non-responsive to current standard pharmaceutical based medical treatment.

According to a recent article “Therapeutic Approaches for the Management of Trigeminal Autonomic Cephalgias” in Neurotherapeutics (April 2018) by Wei and Jensen “ Treatment has become more targeted and aimed towards the pathogenesis of the conditions. The therapeutic targets range from the macroscopic and structural level down to the molecular and receptor level. The structural targets for surgical and noninvasive neuromodulation include central neuromodulation targets: posterior hypothalamus and, high cervical nerves, and peripheral neuromodulation targets: occipital nerves, sphenopalatine ganglion, and vagus nerve. In this review, we will also discuss the neuropeptide and molecular targets, in particular, calcitonin gene-related peptide, somatostatin, transient receptor potential vanilloid-1 receptor, nitric oxide, melatonin, orexin, pituitary adenylate cyclase-activating polypeptide, and glutamate.”

Targets for treating TACs include the Hypothalamus via Deep Brain Stiimulation, The High Cervical Nerves including the Occipital Nerve, the Greater (GON) and Lesser Occipital Nerves. While these can be treated with neuromodulation anesthetic blocking can be very helpful treatment as well. Neuromodulation of the Vagu Nerve is also showing great promise.

This post will focus on the role of the Sphenopalatine Ganglion (SPG) as a treatment target in TACs. The use of Blocks was first described by Greenfield Sluder in 1909. Originally it was blocked via a trans-nasal approach utilizing cocaine. Dr Sluder later published “Nasal Neurology” and became chairman of the Department of Otolaryngology at Washington University School of Medicine in St Louis. The term Sluder’s Neuralgia or Meckel’s Neuralgia is based on Sluder’s work and the exceptionally safe Sphenopalatine Ganglion Block has been utilized for refractory headaches for over 100 years. Dr Hiram Byrd published a paper on “Spehnopalatine Phenomenon” detailing 10,000 successful blocks in 2000 patients in Annals of Internal Medicine (JAMA).

The use of Neuromodulation of the Sphenopalatine Ganglion is currently being investigated with multiple devices on the market or on the way to market. There are also devices designes for Vagus nerve and cervical nerve neuromodulation therapy.

Currently there are also 3 devices on the market for doing trans-nasal delivery of SPG Blocks. The Sphenocath, the Allevio and the TX360 and all three have been shown to be effective in delivering SPG Blocks. These have shown success in treating Tension Headaches, Migraines and TACs. Intra-oral and extra-oral injections of the Sphenopalatine Ganglion are also possible.

The most cost effective and patient friendly method of delivering Sphenoopalatine Ganglion Blocks is for patients too be taught how to self-administer the blocks with cotton-tipped nasal catheters. While the is a “low tech approach” relative to commercially available devices it has numerous advantages.

Self-administration will enable prophylactic treatments to prevent pain as well as allowing patients to turn off their pain at first onset thereby avoiding trips to Emergency Departments and physician’s offices.

From a public health approach this will be extremely cost effective and will reduce suffering associated with TACs, migraines and other types of headaches. Self-administration generally utilizes 2% lidocaine and is incredibly safe.  There is excellent medical rationale for considering self-administered SPG Blocks as a first line medical treatment for prevention and treatment of all chronic headaches disorders. Acute headaches should always be considered a medical emergeny if they are substantially different in symptoms or severity than previous headaches.

Patient administered SPG Blocks allow patients to control their own well being.  The use of Neuromodulation of the Sphenopalatine Ganglion (and other nerves) may change the face treatment of head pain in the future.  Currently, self-administration remains an effective and cost effective approach without surgical risks.

Dentistry has long taken an interest in treatment of headaches and migraines associated with jaw and TM Joint function.  Neuromuscular dentistry utiilizes an Ultra-low frequency TENS that acts as a neuromodulation uniit on the Sphenopalatine Ganglion parasympathetic nerves and the superior Ceviical Sympathetic nerves that pass thru the ganglion.  Cranio, The Journal of Craniomandibular and Sleep Practice is publishing an article on that subject in May, 2019 issue.