Scientist I University of Wisconsin-Madison Madison, United States
Introduction: Anterior petrosectomy provides exposure to anterolateral pons. This approach could be extended to expose the ambient cistern and inferolateral midbrain. Surgical exposure of the vertebrobasilar junction and the basilar trunk is usually not possible unless the vertebral or basilar artery has a tortuous course towards the site of the approach. Our study aims to perform a systematic cadaveric dissection with exposure to the VBJ and basilar trunk with the possibility of surgical manipulation.
Methods: We performed unilateral dissections in 10 cadaveric specimens. After completing the anterior petrosectomy, extradural bone removal was continued towards the clivus. Once the inferior petrosal sinus was exposed, petrosectomy was continued towards the jugular foramen. As the main step, the bone between the carotid canal and the inferior petrosal sinus was removed, and the clivus was exposed and drilled. Dura underlying the petrous bone was opened. Inferior petrosal sinus was ligated closer to the jugular bulb to avoid the sixth nerve damage. Opening the dura underlying the removed part of the clivus exposes the area of interest.
Results: The vertebrobasilar junction area, including the anterior spinal artery along with its tributaries, was exposed in nine specimens (9/10). In one specimen, VBJ could not be seen because of the incomplete caudal fusion of the basilar artery. The course of the sixth nerve between the origin and the inferior petrosal sinus was seen in all specimens. In seven specimens, the origin of the anterior inferior cerebellar artery was seen at the uppermost part of the exposure; however, surgical manipulation around the anterior inferior cerebellar artery origin was restricted.
Conclusion : Extended anterior petrosectomy with partial clivectomy provides sufficient surgical exposure to the vertebrobasilar junction and the proximal basilar trunk.
