Sphenopalatine Ganglion Blocks have been in use for over 100 years. The blocks fell out of use for many years as pharmaceuticals became widely utilized for a wide variety of conditions. Unfortunately, often the the promise of new drugs fell far short of the expected results which led to a new renaissance in the utilization of Sphenopalatine Ganglion Blocks. They are primarily utilized for chronic head and neck pain, migraines, vestibular migraines, tension headaches, cluster headaches and TMJ disorders. but can also be utilized for multiple ENT symptoms, Anxiety, PTSD, for treating Essential Hypertension as well as a wide variety of other issues.
The Spehnopalatine Ganglion is the largest Parasympathetic Ganglion of the head and it is found in the Pterygopalatine Fossa along with the maxillary Division of the Trigeminal Nerve and the Maxillary Artery. The Spenopalatine Ganglion is also know as the Pterygopalatine Ganglion, Meckel's Ganglio9n, Sluder's Ganglion and the Nasal Ganglion and when discussing blocks it is shortened to SPG Blocks. The article Neuromuscular dentistry and the role of the autonomic nervous system: Sphenopalatine ganglion blocks and neuromodulation is an excellent source of information on the wide uses of the Sphenopalatine Ganglion Block. https://www.sphenopalatineganglionblocks.com/spg-blocks-and-neuromodulation/
It is important to not understand that even though the Sphenopalatine Ganglion is a Parasympathetic Ganglion it also contains Somatosensory nerves from the Trigeminal Nerves as well as Post-Ganglionic Sympathetic nerves from the Superior Cervical Sympathetic Ganglion. Sympathetic nerves from throughout the Cervical Sympathetic Chain pass up thru the chain to the Superior Cervical Ganglion and on to the Sphenopalatine Ganglion. These specifically includes nerves from the Stellate Ganglion at the bottom of the Cervical Sympathetic Chain. Blocks to the Stellate Ganglion are often utilized for treating rennisance CRPS or Complex Regional Pain Syndromes. A side effect of these blocks being studied by the US Military and Veteran Hospitals is that sometimes a single shot to the Stellate Ganglion will cure PTSD.
Sluder in his original work described the use of trans-nasal cocaine to deliver anesthetic results. In the years that have followed many approaches have evolved to preform these blocks. Originally, a small pledget of cotton was dipped in Cocaine solution and deposited to the mucosa over the medial wall of the Pterygopalatine Fossa. This solution would pass thru the membrane to the Sphenopalatine Ganglion and the maxillary division of the Trigeminal Nerve.
Sphenopalatine Ganglion Blocks can be administered by a wide variety of methods. These can be divided into two primary groups, trans-nasal administration and injection techniques.
The original trans-nasal method was a cotton pledget but the use of a long Q-tip of applicator is in very common in Emergency rooms. This is still widely utilized today and clinicians use a variety of local anesthetics including lidocaine 2%-5% liquid and 5% lidocaine Gel. This applicator can then be kept in place for 20 minutes. With plastic handle applicators a small bend can lead to more ideal positioning not possible with wooden applicators.
Recent FDA approvals of nasal catheters specifically designed to deposit anesthetic directly on the mucosa over the medial wall of the Pterygopalatine Fossa have widely increased the number of clinicians utilizing SPG Blocks. They are relatively easy to apply and after their introduction the use of the blocks began to spread widely. There are three available devices; the Sphenocath, the Allevio and the TX360. While there are differences they all are capable of delivering anesthetic to the mucosa overlying the fossa. The concept is a well directed squirt gun depositing the anesthetic directly over the medial wall of the fossa. Most practitioners will keep the patient supine for 20 minutes after the delivery of anesthetic. Ideally, the right and left side should be done seperately so the patient can turn their head to the right or left while supine and the anesthetic will stay in the ideal location for a greater period of time.
The most effective application trans-nasally is with the use of a cotton-tipped catheter that can be bent slightly but more importantly offers continual capillary feed of anesthetic to the mucosa on the medial pterygopalatine fossa wall. Supine positioning will lead to faster flow of the anesthetic but the continuous flow makes supine position unnecessary. Even if the patient is upright or moving around there will be continuous flow of the anesthetic and passage to the ganglion. This is extremely important because it allows the ability for longer term continuous delivery of anesthetic it allows for the patient to learn to self-administer the blocks and be able to function while the anesthetic is delivered. They can move around, watch TV, read a book or work on a computer. They can also utilize the blocks on as needed basis without a trip to the ER or their physician. This is especially important if the blocks is used to treat sympathetic overload related anxiety or a chronic pain condition.
The use of injections will give the fastest and most profound anesthesia to the ganglion. Injections can be done intraorally through the Greater Palatine Foramen which is located in the back of the hard palate adjacent to where maxillary third molars are found. The initial injection can be uncomfortable but a small amount of infiltration to the palate will make the rest of the procedure painless. This area is often given anesthetic when taking out wisdom teeth or doing root canal therapy.
It is also possible to do an extra-oral approach to place anesthetic. This can be done through the cheek passing through the masseter muscle or the more convenient route of a Suprazygomatic injection. Some clinicians will use a guided approach but that is not necessary if only anesthetic is being utilized. The guided approach is essential if doing destructive procedures of any type to the ganglion.
Many patients who may require an injection initially may be able to maintain themselves with Self-Administered SPG Blocks or SASPGB. There is both an immediate treatment effect of the blocks and a longer term prophylactic effect. Many patients find they need to self administer the blocks less and less frequently over time.
A new approach to Self-Administered SPG Blocks is Relaspen which is a nasal spray/ catheter combination. It utilizes lidocaine in a very convenient form for breakout headaches. Self-Administered SPG Blocks with continual capillary feed will definitively remain the Gold Standard for SPG Blocks for effectiveness but Realspen will be amazing for emergency use.
