SAFETY OF ABLATION OF THE SIGMOID AND TRANSVERSE SINUSES - AN EXPERIMENTAL-STUDY

If the sigmoid and transverse sinuses could be divided safely, surgeon s could broaden their access during skull base surgery without retract ing the brain extensively. We undertook this study in monkeys to asses s the risk of sacrificing these sinuses. We learned that when bilatera l transverse sinuses were occluded, the sinus pressure measured in the superior sagittal sinus increased significantly as blood was purged f rom sinus venules. Unilateral sacrifice of sigmoid and transverse sinu ses, however, did not change proximal sinus pressure in any ipsilatera l or contralateral sinus. Furthermore, no change in regional cerebral blood flow or motor evoked potentials was seen in the parietal lobe no r did auditory brainstem response change significantly with sinus abla tion. We conclude that, unilaterally, sigmoid and transverse sinuses m ay be ablated safely because collateral circulation via the vein of La bbe, superior petrosal sinus, petrosal vein, and backflow from the tra nsverse sinus to the contralateral sinus may be established.