THE DIRECT CAROTID-CAVERNOUS FISTULA - A CLINICAL, PATHOANATOMICAL, AND PHYSICAL STUDY

In order to further elucidate the pathogenesis of the direct carotid c avernous fistulas (dCCF) clinical, patho-anatomical, and physicomechan ical studies were performed. In 27 of 42 patients the dCCF were found to be localized in the segment C 4 (according to Teufel, 12), in 13 pa tients in segment C 2 and in only 2 patients in segment C 3. The patie nts with dCCF in segment C 4 were significantly younger than those wit h dCCF in the segments C 2 or C 3. In none of the patients fractures o f the bony walls of the cavernous part of the internal carotid artery (ICA) could be ascertained. On human cadavers it was affirmed that the cavernous branches of the ICA arise nearly exclusively from the top o f segment C 3 and from the lateral wall of segment C 2. The strength o f the wall of the cavernous part of the ICA was shown to decline with age as revealed by means of a tensile machine. There were no significa nt differences between the four segments investigated. As revealed by roentgenograms the distensibility of the ICA within its coverings was shown to be greatest in the segments C 2 and C 4 and lowest in segment C 3. A sudden increase of the intraluminal pressure ruptured the ICA exclusively in the segments C 2 and C 4. Histological preparations rev ealed that the trabeculae of the cavernous sinus insert tangentially i nto the adventitia of the ICA. Taken together these findings strongly support the view that the dCCF are mainly due to a sudden increase of the intraluminal pressure of the ICA.