Middle cranial fossa approach to the internal auditory Meatus:A Chinese temporal bone study.

Most techniques applied in the middle cranial fossa approach to the internal auditory meatus were based on anatomic studies in Caucasians. As racial differences in the cranium exist, this paper evaluated the applicability of these techniques in Chinese patients. This paper also evaluated the usefulness of the 30-degree-angled rigid endoscope in identifying the superior semicircular canal (SSC). Thirty Chinese temporal bones were dissected. It was found that, like in Caucasian patients, (1) constant relation exists between the geniculate ganglion and SSC, and (2) the internal auditory meatus of each specimen was situated within a 60-degree angle anterior to the SSC. However, the orientation of the arcuate eminence and its relationship to the SSC in Chinese differed from Caucasians. The endoscope was found to be useful in aiding early identification of the SSC and in differentiating it from surrounding air cells. In conclusion, some recommended landmarks used in hearing preservation via the middle cranial fossa approach may not apply to Chinese patients. The endoscope has the potential to enhance the chances of hearing preservation.