There are a total of 12 cranial nerves which are responsible for transmitting information to and from the brain from the head and neck region. Information like taste, smell and vision travel along these nerves.
When we open our mouth or move our eyes, our brain is essentially sending a command to a group of muscles. One of these cranial nerves (Cranial Nerve V or CN V) is responsible for nearly 80% of the sensory and motor information of the head and face area. The CN V has 3 main trunks thus the name Trigeminal Nerve.
When a nerve gets stimulated, an impulse is sent to the brain and we perceive some sensation. There are different nerves for transmitting different sensations. For instance, sense of touch travels along a different path than the sense of pain. These pathways can be thought of as "highways of information" within the body. In essence, nerves are messengers of information in our body. A normal functioning nerve does not send a signal on its own. It sends a signal (or a message) when a nearby muscle or organ gets stimulated. An example is when your finger gets stuck in the door jamb! Over time though, some nerves develop a disease where they by themselves generate a signal (or message) and send that information to the brain. This is essentially what happens in this disease.
Trigeminal neuralgia is currently thought to be related to compression of the nerve root of the Trigeminal nerve. This compression, caused by an adjacent blood vessel, causes this nerve to become super excitable over time. As a result, the sensations transmitted by the nerve are amplified. There are times when a painful episode starts off a cycle that last several minutes, then goes away for hours only to come back later. These painful episodes sometimes start by stimulation of a trigger point and sometimes spontaneously. There are periods of time lasting from days to weeks to months that the pain is intense. This is usually followed by a period of time, usually months where there is no pain.
Trigeminal neuralgia has sharp, stabbing , electric-like shock type of quality that affects some part of the face. This disease is very debilitating and painful. The pain is usually on one side of the face (around the eye, cheek or lower jaw). It can start by touching some part of the face or even certain sounds. Common day activities can sometimes result in activation of the trigger point.
Treatment for Trigeminal Neuralgia is generally aimed at making the pain more manageable.
First line of defense involves use of medications such as Neurontin, Dilantin, Tegretol and Lioresol. While these medications were not designed specifically for this purpose, it is a side effect that is welcomed. These medications are usually dosed so as to have the maximum benefits while minimizng the side effects.
As painful episodes outpace the periods of remission or as the medications lose their effectiveness, surgical options need to be considered. Surgical procedures can be divided into 2 major categories.
In Microvascular Decompression Surgery, the aim is to relieve the compression on the nerve root caused by a nearby blood vessel. This procedure needs to be performed by an experienced neuro-surgeon to optimize the outcome.
The other technique collectively called Rhizotomies involve causing damage to the nerve root to prevent transmission of pain signals. Essentially, this is equivalent of "killing the messenger". The nerve root is bathed with a toxic chemical (Glycerol) in one technique. In another technique, an electrode is placed near the nerve root and the nerve is damaged using electrical currents. In another procedure beams of radiation are aimed thru the brain with the focus being directed at the nerve root. The outcome of such procedures are greatly dependent on the experience of the surgeon and the surgical facility.