Study on the Three Dimensional Structure of the Human Ossicle Using Micro CT

Abstract

BACKGROUND AND OBJECTIVES: Conventional studies of the middle ear ossicles give relatively limited information on shape, mechanical strength and 3-dimensional relationship. Recently, Micro CT scanning technology has been applied to analysis of skeletal structures. This study aims to reconstruct the 3-dimensional structure of the ossicles, including length, thickness, strength, and the angle. MATERIALS AND METHOD: The structures of ossicles obtained from 3 cadavers were analyzed through micro CT 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-Analyzer(TM) and Ant(TM). Based on the results, the strength, length, and angle of each ossicle were measured. RESULTS: The ratio between the handle of malleus (4.413 mm) and the long process of incus (3.559 mm), which acts as a lever of the middle ear impedance transformer, was 1.24. The volume fraction, indicating relative strengths of ossicles, was higher in the portion close to the articular surface. CONCLUSION: Our preliminary data of the ossicular structure analysed by micro CT scan will be helpful for the elucidation of ossicle's structure and the further development of artificial prosthesis.