Three-dimensional computed tomographic cranial base measurements for improvement of surgical approaches to the petrous carotid artery and apex regions.
OBJECTIVE: The bony and vascular anatomic features in the region of the petrous apex can vary significantly. These variations affect the operative view obtained via extended subtemporal or anterior transpetrosal approaches to cranial base lesions for individual patients. The goal of this study was to evaluate three-dimensional computed tomography as a means of obtaining detailed preoperative anatomic information regarding bony and vascular landmarks and spatial relationships in the region of the petrous carotid artery and petrous apex. METHODS: We radiographically studied 15 patients (30 sides), using 0.8- to 1-mm-thick, reconstructed, computed tomographic images. Special attention was given to the course of the petrous carotid artery. RESULTS: The petrous carotid artery was located lateral to the trigeminal impression. The size of the petrous apex medial to the horizontal petrous carotid artery was observed to be variable. The width of bone from the trigeminal impression to the wall of the internal auditory canal averaged 9.6 mm (range, 5.2-16.1 mm). A variable amount of bone overlying the internal auditory canal (4.5 mm) was also present. Multiple other relationships among key landmarks were quantified. CONCLUSION: There is significant variability in the anatomic features of the petrous apex among patients. For each patient, detailed preoperative information regarding the amount of bone to be removed during a cranial base procedure can be obtained using three-dimensional computed tomography. This information may be critical for determination of the amount of extra exposure that can be achieved via an anterior petrosectomy for each patient.
Villavicencio, AT; Leveque, JC; Bulsara, KR; Friedman, AH; Gray, L
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