The Sphenopalatine Ganglion (SPG) is a group of nerve cells that is linked to the trigeminal nerve, one of the main nerves that has been shown to be involved in various forms of head pain such as migraine. The SPG is located behind the nose/nasal cavity and carries information about sensation, including pain. It also plays a role in autonomic (involuntary) functions, such as tearing and nasal congestion.
It is thought that the link between the SPG and the trigeminal nerve may be important in in some cases of headache/migraine & that if you apply local anesthetics/numbing medications to block or partially block the SPG it may be helpful in reducing head and facial pain.
SPG blocks were first described in the 1900’s using a technique involving the application of numbing medication on to cotton swabs then placed into the back of the nose.
However in the last few years’ newer, more specific techniques are being tested. These involve placing a very thin plastic tube into the nose to insert numbing medication (such as the local anaesthetic lidocaine) in and around the SPG.
Initial trials in America (on 112 migraine suffers) have shown that even after the initial numbing created by the anaesthetic wears off, 88% patients experienced some reduction in migraine frequency, &/or severity, for at least a month.
Clearly this is only a small trial & it remains to be seen if improvements are maintained over time &/or whether the procedure has to be repeated to ensure continued pain relief.
Research into other techniques, such as using lasers instead of anaesthetics, may be as, or more, effective & indeed whether more permanent blocks to the SPG may be helpful in certain cases.
Interestingly there is also some evidence to show that electrical stimulation to the SPG may also relieve some forms of head/face pain. Studies are ongoing, and results should be out within the next few years. This procedure typically requires implantation of a neurostimulator device through the mouth under general anesthesia & positioned at the SPG. However as with other oral and facial surgery, the procedure carries surgical risks, and numbness, pain and sensitivity in the face, gums and teeth is be more common than in SPG blocks (though typically are temporary side effects).
My personal view is that further studies are required before one can say if the above techniques have an important part to play in the management of headaches & migraine. However, they may well be worth considering in cases that are resistant to other forms of treatment &/or may be of particular benefit for those sufferers whose migraines are specifically triggered, or aggravated, by strong smells or whose symptom picture includes those of nasal congestion/discharge.