Figure. Dr. Gary S. Gronseth
Q Is there evidence that surgery is effective for trigeminal neuralgia?
Dr. GARY S. GRONSETH RESPONDS:
A Trigeminal neuralgia is a neurological condition characterized by severe recurring pain on one side of the face. It is caused by a small amount of damage to the trigeminal nerve. Physicians theorize that in most cases the damage is caused by a blood vessel in contact with the trigeminal nerve. Typically, physicians prescribe medication at the beginning of treatment—the most effective being carbamazepine and oxycarbazepine. For 20 percent of patients medications won't work.
When medications fail, surgical options are considered. But by the rules in which physicians classify evidence, none of the surgical techniques have been studied in a rigorous way; therefore, the evidence is considered somewhat weak. Among the surgical options used to treat the condition are: gamma-knife radiosurgery, which delivers a high dose of radiation to the nerve; percutaneous balloon compression of the trigeminal nerve, in which a catheter is inserted through a hole in the skull and a balloon is inflated to compress the nerve; or percutaneous glycerol rhizotomy, in which the chemical glycerol is injected into the brain to damage the nerve. The results of these treatments seem to wear off quickly: Although 90 percent of people respond initially to the treatment, within three to five years symptoms recur in about 50 percent of patients. However, the procedure can be repeated.
Another option is microvascular decompression; the surgeon exposes the trigeminal nerve and places something between it and the blood vessel that's touching the nerve. About 90 percent of patients experience a drastic reduction in pain after the procedure, and the effects of the procedure last about five years for 75 percent of patients. There are some major risks associated with microvascular decompression, but with the advantage that the effects last much longer.
Gary S. Gronseth, M.D.
Vice chairman of the department of neurology at the University of Kansas Medical Center in Kansas City, KS.