The Effect of Race on the Exposure of the Internal Auditory Canal Via the Retrosigmoid Approach in Turkish Subjects

Hearing conservation in acoustic neuroma surgery via the retrosigmoid approach depends upon a good exposure of the internal auditory canal from behind avoiding labyrinthine injury. The accessibility is influenced largely by the individual characteristics of the temporal bone and the variability of the surgical landmarks is the result of different skull base shapes among different races. The aim of this study was to evaluate the effect of race on the exposure of the internal auditory canal of Turkish subjects via the retrosigmoid approach. Axial temporal bone CT scans of 40 Turkish individuals were studied by measuring the relevant parameters and the results were statistically analysed and compared with those reported previously for Chinese and Europeans (3). The results showed significant differences in the position of the sigmoid sinus, orientation of the petrous bone and posterior fossa dimensions. This led to the conclusion that a bigger craniotomy is needed in Turkish individuals than in Chinese and Europeans.