COMPUTED TOMOGRAPHIC EVALUATION OF SURGICALLY SIGNIFICANT VASCULAR VARIATIONS RELATED WITH THE TEMPORAL BONE

Variations of the vascular structures related with the temporal bone m ay cause important problems in diagnosis, treatment planning and surge ry. High resolution computed tomography (CT) scans of 700 temporal bon es of 350 patients were retrospectively examined for the incidence of dehiscent jugular bulb, high jugular bulb, diverticulum of jugular bul b, anteriorly located sigmoid sinus and dehiscent internal carotid art ery. Dehiscent jugular bulb was seen in 27 (3.9%), high jugular bulb w as seen in 142 (20.3%), jugular bulb diverticulum was seen in 55 cases (7.9%). The average distance between external acoustic canal and sigm oid sinus was found to be 13.3 mm and in 12.4% of the cases this dista nce was < 10 mm. Of 700 temporal bones, 10 (1.4%) showed dehiscent car otid canal. To aid diagnosis, treatment planning and surgery, CT scann ing is currently a very reliable tool in determining these conditions. Special attention should be paid to the position of the vascular stru ctures in the preoperative temporal bone CT scans.