Volume Fraction of the Human Pathologic Ossicles Destructed by Cholesteatoma Using Micro-CT

Background and Objectives：Conventional studies for the middle ear ossicles destructed by cholesteatoma give relatively limited information on shape, mechanical strength and 3-dimensional relationship. Recently, Micro-CT scanning technology has been applied to analysis of skeletal structure. This study aims to reconstruct the 3-dimensional structure of normal ossicles and destructed ossicles by different cholesteatomas and to compare volume fraction of destructed ossicles with that of normal ossicles. Materials and Method：13 pathological ossicles obtained during cholesteatoma surgery were used in this study (2 malleuses and 2 incuses from attic cholesteatoma；1 malleus and 2 incuses from sinus cholesteatoma;2 malleuses and 2 incuses from tensa retraction cholesteatoma；2 incuses from congenital cholesteatoma). As a control, normal ossicles harvested from cadaveric temporal bone specimens were used. The structure of obtained ossicles was analyzed through Micro-CT (SkySan-1072, Belgium) by filming the 2-dimensional cross section image running perpendicular to the long axis of the ossicles. The 3-dimensional images were thereby reconstructed for each, and were analyzed using CT-AnalyzerTM and ANTTM. Based on the results, the strength of each ossicle were measured. Results：The volume fraction, indicating relative strengths of ossicles, was lower in the portion of destructed surface. The pattern of destructed ossicles by cholesteatoma was different according to pathological status of cholesteatoma. Conclusion：Our preliminary data of ossicular structure analyzed by Micro-CT scan will be helpful for elucidation of pathological ossicles in middle ear cholesteatoma and will make a great contribution to research of middle ear cholesteatoma.