[Causative relationship between cranial base deformities and trigeminal neuralgia]

From a series of 110 cases of surgically treated trigeminal neuralgia the author reports two cases in which impressio basilaris was the cause of neuralgia. One of these patients was operated on by the method of Frazier-Spiller, the other by Dandy's method in a microsurgical modification. These two methods gave the author an opportunity of comparing intraoperative findings in the middle and posterior cranial fossa. In the middle cranial fossa besides deformity of the base of the skull thinning was found of the dura, flattening of Gasser's ganglion and the postganglionic fibres of the trigeminal nerve were taut on the edge of the pyramid. In the posterior fossa the pontocerebellar angle was crowded despite removal of some cerebrospinal fluid. The postganglionic fibres of the trigeminal nerve were closely adherent to the pons and were visible on a small distance from the tentorium to the pons. In both cases postganglionic rhizotomy was done and the patients were relieved from pain.