Categories
Pain Physiology Treatment Options

SPG Blocks

The previous post, Ganglia, Facial Nerves, & the SPG, described ganglion structure and function and the relationship of the SPG (sphenopalatine ganglion) and how it’s related to other facial nerves.

The SPG is is a focal point for two cranial nerves, covering from the temples forward, down through the jaw, and back to the ears. These nerves are involved in a number of pain conditions – migraines, cluster headaches, NDPH, temporomandibular joint pain (TMJ), and trigeminal neuralgia. Blocking the SPG with a local anesthetic has been used to treat all of these conditions.

cross-section of face showing maxillary nerve

The SPG is a parasympathetic ganglion primarily innervated by the facial nerve (Cranial Nerve VII). It also includes connections to the maxillary nerve (the second branch of the trigeminal nerve (Cranial Nerve V.)) The SPG is located deep inside your head, all the way at the back of the sinus cavity.  It is in-line with the middle concha of the turbinate bones in your nose and directly above where the back of your soft-palette ends in your throat. So, quite deep inside your head. If you’ve ever looked at a skull, you may have noticed that inside the nasal cavity there are thin bone that run between the eyes. Those bones are covered with tissue and protect the SPG.

Despite being so deep, the SPG can be accessed without needles. You enter through the nose.

The goal of an SPG block is to apply a local anesthetic – often lidocaine – to the tissue covering the SPG. You may have experienced lidocaine before. It is the anesthetic a dentist will swab in your mouth prior to injecting novocaine.

The lidocaine soaks into the tissue, numbing the SPG. This blocks information from the facial nerves from passing information on the brain. Sometimes this will last only as long as the lidocaine. However, sometimes the treatment can calm a misfiring nerve enough that it will behave itself until restimulated. For example, my son had sinus surgery to correct a severely deviated septum. At the time, he was having migraine spikes that lasted over 40 days with no respite. This had been going on for several years.

After surgery, he began to develop a new type of headache – neuralgia – that clearly originated at the surgery site. The doctor recommended an SPG block. Immediately after the SPG block, he did not have a migraine attack for almost five weeks – the longest pain-free stretch he’d had in years. After several successful blocks, with pain-free stretches each lasting over a month, the new headache type from the surgery site completely stopped. Repeated suppression from the lidocaine allowed the nerve to heal.

That’s the goal for all SPG blocks. Although his migraine attacks eventually returned, the neuralgia never did.

There are many different ways of getting lidocaine to the SPG. The one described here is very simple. It is done with a long cotton swab and a syringe attached to a tube.

Equipment for performing the simplest form of an SPG block. Crab optional.

How does it work?

The principle is simple. Liquids like to follow a simple path downwards. You’ve probably seen water run down a rope. This works the same way. You put the cotton swab deep down your nose. Then you let the lidocaine run down the swab to the tissue over the SPG. It’s literally that simple.

Step 1: Insert the cotton swabs as guides. In the picture above, you see two paper-wrapped cotton swabs – long (very long) wood Q-tips. That’s what is going to go up your noses. (Honestly, until I saw this done I had no idea you could put something that far up your nose. Or the angle that those holes in your nose go.)

Note here, as you are suppressing a shudder, that the long swab is soaked in a local anesthetic, like lidocaine. This dulls the sensation of the swab traveling the entire length of your nose until it bumps into the tissue covering the SPG.

Step 2: Run the tube attached to a syringe of anesthetic up your nose along the swab. After the swab is as deep as it can be (you can actually feel it bump into the tissue over the SPG), it’s time to apply the lidocaine. In the picture above, you can see how thin the tubing is (it’s attached to the syringe the crab is holding).

The syringe is full of licodaine. When you squeeze the syringe, the lidocaine goes down the tube. It runs down the swab, allowing accurate delivery of a premeasured amount to perfuse the area around the sphenopalatine ganglion. 

Here, the pateint is slowly using the syringe to perfuse lidocaine into the tissue covering the SPG.

Often, the application and perfusion is done by a doctor or clinician. When my son had it done, his doctor trained him to do it himself. The first time he went, the doctor showed him how to do it, but let him do the procedure under supervision. The allowed him to control the flow and increase his comfort. The second time, he did it entirely himself in the clinic. After that, he did the procedure himself at home.

These topical treatments of the local anesthetic to block the SPG can bring rapid relief, often inside thirty minutes. How long it lasts, depends entirely on the problem presented.

Check out the 1step2life app!

Start where you are. Set your own goals. Take back your life. A tool for tracking goals, emotions, and success, not just logging pain. And the only app that has a mode specifically for parents, partners, and other carers that supports effective coaching and strong relationships.

Download on the App Store
Get it on Google play