Skull anatomy via subtemporal transpetrosalridge approach

Abstract

Objective To establish standard sites for bur holes that maintain constant anatomical relationships with the skull base and neural structures and can serve as the basal aspect of supratentorial temporooceipital craniotomies such as subtemporal transpetrosalridge approach.Methods To determine cranial-cerebral relationships,the authors delimited 10 adult cadaveric skulls anteriorly and posteriorly the external projection of the petrous bone and the midbrain by CT and Titanium nail.Then bur holes in adult cadaveric skulls were created (kl,the first bur hole,located anterior to the auricle of the ear; k2,the second bur hole,whose base was located 1 cm above the interface of the parietomastoid and squamous sutures; k3,the third bur hole whose base was located 1cm above the asterion).Three bur holes were made on each of the skulls (20 cerebral hemispheres).The author then introduced plastic catheters through the bur holes to evaluate pertinent cranial and neural landmarks.Results The first bur hole appeared to have a particular anatomical relationship with the anterior aspect of the petrous portion of the temporal bone and the most anterior aspect of the midbrain.The second bur hole had a particular relationship with the posterior border of the petrous portion of the temporal bone and with the posterior aspect of the midbrain.The third bur hole was mostly supratentorial and particularly related to the preoccipital notch.Conclusions The middle fossa floor is located anterior to the site of the kl,and the superior surface of the tentorium is posterior to k2.Together with k3,these bur holes can be considered standards for temporooccipital craniotomies such as subtemporal transpetrosalridge approach. Key words: External projection; Skull base; Subtemporal transpetrosalridge approach; Anatomy