The convergence of the spinothalamic and the secondary trigeminal tracts in the pons makes it possible to section the pain pathways from one half of the body without appreciably damaging other nerve structures. This may be accomplished in the upper part of the pons or the mesencephalon. Dogliotti,1 who first suggested section of these pathways in the brain stem, made his incision in the rostral portion of the pons. Because of the easier surgical approach and the clearer surface markings of the pain tracts in the mesencephalon, this level seems more favorable for the section (fig. 1). Two cases in which this procedure was carried out have been previously published.2 Three additional cases are reported here.
REPORT OF CASES
Case 1.
—A. S., a 26 year old bartender, was admitted to the University of Chicago Clinics, service of Dr. Charles Huggins, on April 1, 1940. Three to four