The sphenopalatine ganglion is the largest aggregation of neurons (nerve cells) in the head aside from the brain. It lies in the pterygopalantine fossa (deep in the midface, behind the nose) and receives sensory input from the maxillary nerve of the trigeminal nerve (cranial nerve V), as well as some autonomic connections to the facial nerve (cranial nerve VII). The upper cervical nerve roots (in particular C2, C3, C4) can also have indirect connections with the sphenopalantine ganglion. These factors make the sphenopalatine ganglion is an effective target for blocking pain signals from the head and facial area, upper cervical spine, neck and upper back. The sphenopalatine ganglion (SPG) block is a procedure that injects a local anesthetic and/or a corticosteroid (a powerful anti-inflammatory drug) near the ganglion, blocking pain signals.
What conditions benefit from a sphenopalatine ganglion (SPG) block?
Numerous conditions have been shown to benefit from a sphenopalatine ganglion block. This procedure was invented in 1909, and the operative technique has continually improved. SPG blocks have been proven to provide benefit in the following conditions:
Pain of musculoskeletal origin
Pain of vascular origin
Temporomandibular joint pain
Interestingly, the SPG block has also been shown to be of some use in relieving the symptoms of nicotine addiction.
How is the SPG block performed?
The SPG block is usually done under sedation, so you probably won’t be around to stay awake while it is being done. Your vital signs will be monitored continuously after sedation.
There are various techniques that can be used to perform the SPG block, and the use of each procedure will depend on the particular circumstances of your case and/or the training of your physician. Most SPG blocks are performed under fluoroscopic (X-ray) guidance, although in recent years, other methods of guidance (such as CT scans, MRIs, and ultrasound) have emerged. Once the needle is in the correct position, as determined by imaging/guidance, the solution of anesthetic and/or corticosteroid is injected. The procedure can take anywhere from 15 to 30 minutes.
The SPG block can also be done topically, by introducing a cotton-tipped applicator through your nose and along the upper turbinate until it reaches the posterior wall of your nasopharynx. The applicator is left in place for 30 minutes before it is withdrawn.
What are the outcomes of the SPG block?
Most patients can easily tolerate the SPG block and report favorable outcomes. Multiple studies have confirmed that SPG blocks leads to the alleviation of pain symptoms, in conditions as varied as cluster headaches, to trigeminal neuralgia. Success rates of over 70% are consistently reported.
However, there are always risks to the procedure. You may experience a bad taste in your mouth from the local anesthetic dripping down the nasopharynx; this sensation is often accompanied by an uncomfortable numbness. The risk of infection is always there, as well as the risk of bleeding. Some patients have also reported lightheadedness after the procedure, though this normally resolves. SPG blocks normally have favorable outcomes, and such adverse outcomes are rare, and usually easily managed.
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