[Study of the anatomy related to cochlear implantation guided by HRCT].

Objective: In order to provide help for preoperative assessment of cochlear implantation, related dissection of temporal bone was conducted guided by high resolution computerized tomography (HRCT) in accordance to the main steps of cochlear implantation, and was compared to HRCT measurements on a viewing workstation.

Method: Six temporal bones were dissected according to the main steps of cochlear implantation and scanned in axial and semilongitudal planes by HRCT to observe the relationship between anatomy and HRCT.

Result: The width of facial recess in dissection was (3.13 +/- 0.34) mm at the level of round window, and (4.12 +/- 0.44) mm at the level of oval window. The width of facial recess in HRCT was (3.20 +/- 0.38) mm at the level of round window, and (4.14 +/- 0.47) mm at the level of oval window. The whole course of facial nerve was visualized clearly in semilongitudal plane. No statistically significant differences were found between the results of dissection and HRCT.

Conclusion: The distance in axial between facial nerve and posterior wall of external auditory canal and the distance from facial nerve to round window in semilongitudal plane are the most important parameters which reflect the position of facial nerve. The vertical portion of facial nerve, posterior wall of external auditory canal, round window are important measurement landmarks. Related preoperative measurements of cochlear implantation by HRCT can help to guide clinic surgery.