Overview of Sphenopalatine Ganglion Block
The sphenopalatine ganglion (SPG), which plays a key role in generating pain, was first talked about and used as a treatment method by a man named Sluder back in 1908. He identified a condition named ‘sphenopalatine neuralgia’, which involves severe face pain on one side and is accompanied by issues in nerve function, muscle movement, sense of touch, and taste.
Currently, blocking the SPG is used as a treatment method for several conditions causing pain. In simpler terms, doctors block or stop this group of nerve cells (the SPG) from functioning in order to alleviate pain in patients.
Anatomy and Physiology of Sphenopalatine Ganglion Block
The SPG is a component of the body’s nerve network that lies within a space in the skull known as the pterygopalatine fossa. This space is surrounded by various structures including the back wall of the maxillary sinus, the medial pterygoid plate, the sphenoid sinus, a part of the palatine bone, and a section that joins with the infratemporal fossa. The SPG is behind the middle nasal turbinate and maxillary sinus and it has numerous nerve connections facilitating communication between different parts of the body like sensors for touch and temperature, and automatic body functions like heartbeat.
Sensory Nerves
The maxillary branch of the trigeminal nerve, which passes through a hole called the foramen rotundum, is connected to the SPG. The SPG receives sensory signals from the maxillary nerve. These signals come from the membranes inside your nose, the soft part at the back of the roof of your mouth (soft palate), and parts of the throat (pharynx).
Automatic Nerves
The SPG is involved in sympathetic and parasympathetic innervation, which are parts of your autonomic nervous system handling your body’s automatic functions like heart rate and digestion. In the sympathetic system, nerve signals originate from fibers in the upper part of your spine. These signals eventually reach the SPG and then head to your tear gland, the inner lining of your nose, and the inner lining of your mouth.
The SPG also receives parasympathetic signals – these start from the superior salivatory nucleus, an area inside a part of the brain known as the pons. These signals are involved in controlling the secretion of mucus in your nose, mouth and throat, the production of tears, and responsible for certain functions related to your brain’s protective layer and blood vessels.
After leaving the SPG, some of these nerve signals form the superior posterior lateral nasal and pharyngeal nerves. The SPG also directly connects with the greater and lesser palatine nerves.
When a Person Should Avoid Sphenopalatine Ganglion Block
A person may not be able to have an SPG block (a type of pain relief procedure) for a few reasons:
If they are allergic to any of the medications used in the procedure, it’s not safe to proceed.
If they are on blood-thinning medications (or anticoagulants), it might raise the risk of bleeding and so it’s not recommended.
If they’ve had face injuries in the past, this might make the procedure more complicated or dangerous.
Having an infection can also make the procedure risky because it could spread or get worse.
And of course, if the patient simply doesn’t want the procedure (patient refusal), it won’t be done.
Equipment used for Sphenopalatine Ganglion Block
Doctors often use a variety of medications to perform what’s called an SPG block. These can include local anesthetics like cocaine, lidocaine, or bupivacaine, as well as depot steroids or phenol. The SPG block is performed to block nerves and help relieve pain. An SPG block can be done using a cotton tip applicator or catheter introduced through the nostrils.
In performing this procedure, there are three officially approved devices. However, it’s worth noting that there isn’t much information about how effective and easy-to-tolerate two of these are. These devices, or catheters, are inserted through the front of the nasal passage and positioned above the middle part of the inside of the nose, which is called the middle nasal turbinate.
These devices are made up of a flexible outer layer with an inner extendible catheter that has a curved tip. The Tx360 device is another type that is introduced and pushed forward to a position below the middle nasal turbinate.
The tip of the catheter is positioned in such a way that it is on the medial side, beneath and behind the target mucosa (the tissue it’s intended to affect). This is designed to send the anesthesia in an upward, outward, and forward direction. A curved blunt needle about 10 cm long, with a gauge size 20 or 22, is usually the preferred choice for an approach that is below the cheekbone, known as the infra-zygomatic approach.
As an alternative, a needle with a gauge size of either 22 or 25, around 3.5 inches long, and with the very end curve at a 15-degree angle can be used. For this method, a device known as a C-arm and a small amount of nonionic, water-soluble contrast liquid are needed. If the doctor chooses the transoral approach (through the mouth), a curved dental needle is used.
Preparing for Sphenopalatine Ganglion Block
Before a medical procedure, it’s crucial to know if the patient is taking any blood-thinning medicines or medicines that help decrease the chances of a clot formation. These medicines include anticoagulants and antiplatelet therapies, and could affect how the body responds during the procedure. If a patient is taking such medicines, the doctor performing the procedure may need to speak with the patient’s regular doctor or heart specialist. They’ll discuss the best way to ensure the patient’s safety during the procedure.
Following the advice of these specialists, they may temporarily stop medications like warfarin, heparin, and factor 10a inhibitors. Specific tests like a prothrombin time test (for patients on warfarin) or a partial thromboplastin time test (for patients using heparin) can provide important information about how quickly the patient’s blood is clotting. These tests will be done before the procedure.
Also, the doctor will check the patient’s blood pressure and heart rate before and after the procedure on the same day. During the procedure, the patient will be laid flat on their back with their neck straightened.
Furthermore, the doctor will examine the patient’s nasal passages to see if anything might cause blockage like a bent nasal septum or a growth (neoplasm). All these measures are taken to ensure patient’s safety and make sure the procedure goes well.
How is Sphenopalatine Ganglion Block performed
A sphenopalatine ganglion (SPG) block can be administered through three different methods: transnasal (through the nose), transoral (through the mouth), or transcutaneous (through the skin).
The transnasal method involves placing a cotton-tipped applicator coated in local anaesthetic (something to numb the area) inside the patient’s nose. This applicator may need to be left in for about 30 minutes. This method is very straightforward, quick, and carries a low risk of complications like nose bleeds and infection. However, to work properly, it depends on the anaesthetic spreading across the nasal tissues.
The transnasal injection is a similar method, but it involves inserting a specialized device into the nostril to deliver the anaesthetic. Again, this method is simple and quick with low risk, but relies on the anaesthetic spreading effectively.
The transoral approach involves using a curved needle to treat the SPG through the roof of the patient’s mouth. This method provides more direct access, but is more complex, slightly more risky, and potentially uncomfortable for the patient.
The infrazygomatic approach requires making a small incision through the skin above the upper jaw, using a needle to reach the SPG. This method, which uses imaging technology like fluoroscopy or computed tomography (CT scan), allows for a very precise delivery of the anaesthetic.
Each method has its own benefits and drawbacks, and the choice of method will be determined by the patient’s personal needs and the doctor’s professional judgement.
Possible Complications of Sphenopalatine Ganglion Block
When a medical technique known as an SPG block is done, some people might experience minor side effects. These usually only affect the area where the procedure was done and might include a nosebleed (epistaxis), temporary loss of feeling (anesthesia), or decreased feeling in the base of the nose, throat, and roof of the mouth (hypoesthesia). The eye on the same side as the procedure (ipsilateral eye) might also tear up more than usual.
It’s not common, but there can be more serious problems too. These could include an infection if the procedure wasn’t done cleanly, or bruising and bleeding in the area around the eyes (known as a hematoma), either locally or at the back of the eye (retroorbital).
What Else Should I Know About Sphenopalatine Ganglion Block?
An SPG block is a medical procedure that can be used to help control various types of headaches and facial pain. The effectiveness of this procedure can vary, depending on what’s causing your pain. The goal of an SPG block is not just to reduce pain, but also to improve your day-to-day functioning, lessen your dependence on healthcare services, and potentially decrease the need for opioid medications, which can have serious side effects.
If an SPG block, which involves the use of a local anesthetic to relieve pain, only works for a short time, doctors can consider other options to help prolong pain relief. These include something called radiofrequency neurotomy, which uses a specific type of energy to numb nerves and reduce pain, or SPG stimulation, which uses electrical impulses to do the same.
Because of how it is used, an SPG block can also serve as a diagnostic tool, helping doctors determine the most effective way to manage your pain. It’s commonly used for this purpose.
