At the University of Pittsburgh School of Medicine, he was the first Walter Dandy Professor of Neurological Surgery.
Jannetta suspected that this abnormal impingement of the nerve might be the cause of the painful facial condition known as trigeminal neuralgia.
He devised the microvascular decompression procedure to treat patients with the condition.
In addition to helping trigeminal neuralgia patients, the procedure became a treatment option for several related conditions.
[2][6] Dr. Jannetta served as the Secretary of Health for the state of Pennsylvania during the term of Governor Tom Ridge from 1995 to 1996.