Surgical exposure and resection of the vertical portion of the petrous internal carotid artery: Anatomic study

OBJECTIVE: The goals were to determine which surgical approaches, i.e., the preauricular subtemporal infratemporal fossa (PSI), postauricular transtem poral (PAT), and/or subtemporal middle fossa (SMF) approaches, provide opti mal exposure of the anterior, posterior, medial, and lateral aspects of the vertical segment of the petrous internal carotid artery (VPCA) and to dete rmine the length of the VPCA that can be resected before a vein graft is ne cessary. METHODS: Using 22 cadaveric specimens, we compared the length of exposure o f the VPCA provided by the PSI, PAT, and SMF approaches. The segment of the VPCA that was exposed with each approach was measured in millimeters and e xpressed as a percentage of the total length of the VPCA. Resection of the VPCA in 1-mm increments was performed until a graft would be necessary; the total length of the resected segment was recorded in millimeters and was a lso expressed as a percentage of the total length of the VPCA. RESULTS: The PSI approach provided average exposures of 14.1 mm (95% of the total exposure possible) of the anterior aspect and 14.3 mm (96%) of the l ateral aspect of the VPCA; resection of less than 2.3 mm (16%) of the VPCA could be repaired with an end-to-end anastomosis. The PAT approach provided average exposures of 10.5 mm (71%) of the lateral aspect and 10.0 mm (76%) of the posterior aspect of the VPCA; resection of less than 2.8 mm of the VPCA could be repaired with an end-to-end anastomosis. The SMF approach pro vided average exposures of 6.1 mm (45%) of the anterior aspect and 5.4 mm ( 41%) of the lateral aspect of the VPCA; resection of less than 2.4 mm (24%) of the VPCA could be repaired with an end-to-end anastomosis. CONCLUSION: Lesions on the anterior and lateral aspects of the VPCA can be fully exposed with the PSI approach or partially exposed with the less inva sive SMF approach. Lesions on the posterior aspect of the artery are best e xposed with the PAT approach. Lesions on the medial aspect of the VPCA cann ot be exposed unless the VPCA is mobilized in the PSI approach. Resection o f less than approximately 2.5 mm (20%) can be repaired with an end-to-end a nastomosis, regardless of the approach used.