Trigeminal neuralgia.

Trigeminal neuralgia (TN) is the most common facial neuralgia, and is considered to be one of the most painful conditions to affect patients. The rate of occurrence of TN in men and women is 2.5 and 5.7 per 100,000 per year respectively. TN is generally characterized by lancinating, unilateral, paroxysmal pain occurring in the distribution of the fifth cranial nerve. The diagnosis of TN is made clinically by excluding other possible causes of facial pain and is based on signs and symptoms from the patient history such as a trigger zone, typical unilateral lancinating paroxysms following neural disturbance, and a refractory period. Generally, TN can be diagnosed by the typical patient history, a negative neurologic exam, and response to a trial of carbamazepine. Imaging studies should be considered if the diagnosis is uncertain or neurologic abnormalities are noted. Most cases are caused by compression of the trigeminal nerve root, usually within a few millimeters of entry into the pons. In a few cases, TN is caused by a primary demyelinating disorder. The treatment modalities for the management of TN may be divided into medical, surgical, and gamma-knife radiosurgery. Generally, response to drug therapy is good, with over 80% of patients responding to some of the anticonvulsants. Percutaneous approaches to trigeminal gangliolysis are considered to have less associated risk and less cost than open surgical procedures. Three different techniques may be used to perform percutaneous destruction of the ganglion: percutaneous radiofrequency trigeminal gangliolysis (PRTG), percutaneous balloon microcompression (PBM), and percutaneous retrogasserian glycerol rhizotomy (PRGR). Open surgical procedures used in the treatment of TN include microvascular decompression of the trigeminal root and retrogasserian rhizotomy. Additionally, because both of these procedures have greater associated risks, morbidity, and mortality, they are customarily applied only to younger patients in good health. Stereotactic radiosurgery has been established as an alternative treatment for patients who do not respond to optimal medical management.