The removal of a portion of the occipital bone has become a well established and frequently used surgical method of approach in operations on certain of the cranial nerves. The posterior cranial fossa is opened on the side indicated, and the roots of the nerves may be identified as they pass from the brain toward their exit through the dura mater and the cranial foramina.
The sensory root of the trigeminal nerve may thus be exposed and sectioned for the relief of tic douloureux. For a similar intense glossopharyngeal neuralgia, the ninth cranial nerve may be reached and cut. By the same route the vestibular portion of the acoustic nerve has been divided to provide relief from the intolerable vertigo of Ménière's disease.
In all of these procedures surgeons have encountered certain hazards and complications which have added considerably to the difficulty of performing the operation successfully. One of the