Before 1900 the surgical treatment for tic douloureux consisted of removal of the gasserian ganglion. Since that time a number of different procedures have been advocated. Spiller (1898) was the first to propose division of the root posterior to the ganglion. Frazier performed this operation in 1901. Korteweg,1in 1899, was the first to divide the root. The patient operated on by Korteweg was relieved from pain for twelve years, when it reappeared over the distribution of the first branch. In 1919, Frazier divided only the sensory root, thus preserving the motor division. In 1927, Zaayer2used a more radical procedure. He preserved the motor root, but extirpated the ganglion. Frazier,3in 1915, performed a partial division of the sensory root. As a result of phylogenetic and embryologic studies, Frazier came to the conclusion that the peripheral branches of the ganglion were represented in the mesial, central