Application of stereotactic principles to the treatment of trigeminal neuralgia.

The application of neuroanatomical and neurophysiological principles to the functional surgery of the trigeminal nerve is discussed. Particular attention has been directed toward correlating the three-dimensional anatomical features of the trigeminal nerve and the surrounding structures to the two-dimensional radiograph of this same region. In this regard, 20 trigeminal nerves, including the surrounding neurovascular structures from 10 cadaver sphenoid blocks, were examined. Measurements of the third, fourth and sixth cranial nerves in relation to the profile of the clivus were made from lateral radiographs of the sphenoid blocks. The position of the internal carotid artery in relation to these structures was also noted. These neurovascular relationships are of clinical importance when using the percutaneous thermocoagulation technique for the treatment of trigeminal neuralgia.