Causes
The trigeminal nerve is a mixed cranial nerve responsible for sensory data such as tactition (pressure), thermoception (temperature), and nociception (pain) originating from the face above the jawline; it is also responsible for the motor function of the muscles of mastication, the muscles involved in chewing but not facial expression.Several theories exist to explain the possible causes of this pain syndrome. It was once believed that the nerve was compressed in the opening from the inside to the outside of the skull; but leading research indicates that it is an enlarged or lengthened blood vessel – most commonly the superior cerebellar artery – compressing or throbbing against the microvasculature of the trigeminal nerve near its connection with the pons. Such a compression can injure the nerves protective myelin sheath and cause erratic and hyperactive functioning of the nerve. This can lead to pain attacks at the slightest stimulation of any area served by the nerve as well as hinder the nerves ability to shut off the pain signals after the stimulation ends. This type of injury may rarely be caused by an aneurysm (an outpouching of a blood vessel); by an AVM (arteriovenous malformation); by a tumor; such as an arachnoid cyst or meningioma in the cerebellopontine angle; or by a traumatic event, such as a car accident.Short-term peripheral compression is often painless. Persistent compression results in local demyelination with no loss of axon potential continuity. Chronic nerve entrapment results in demyelination primarily, with progressive axonal degeneration subsequently.
Percutaneous radiofrequency thermorhizotomy may also be effective as may stereotactic radiosurgery; however the effectiveness decreases with time.Surgical procedures can be separated into non-destructive and destructive:

Non-destructive
Microvascular decompression – this involves a small incision behind the ear and some bone removal from the area. An incision through the meninges is made to expose the nerve. Any vascular compressions of the nerve are carefully moved and a sponge-like pad is placed between the compression and nerve, stopping unwanted pulsation and allowing myelin sheath healing. Destructive
All destructive procedures will cause facial numbness, post relief, as well as pain relief. Percutaneous techniques which all involve a needle or catheter entering the face up to the origin where the nerve splits into three divisions and then damaging this area, purposely, to produce numbness but also stop pain signals. These techniques are proven effective especially in those where other interventions have failed or in those who are medically unfit for surgery such as the elderly. Balloon compression – inflation of a balloon at this point causing damage and stopping pain signals. Glycerol injection – deposition of a corrosive liquid called glycerol at this point causes damage to the nerve to hinder pain signals. Radiofrequency thermocoagulation rhizotomy – application of a heated needle to damage the nerve at this point. Stereotactic radiosurgery is a form of radiation therapy that focuses high-power energy on a small area of the body

Support
Psychological and social support has found to play a key role in the management of chronic illnesses and chronic pain conditions, such as trigeminal neuralgia.