OBJECTIVE The objective of this study was to evaluate the effect of crimping of thepiston to the long process of the incus on sound transmission in the middle ear of the temporal bone model, and to use this information to guide stapes surgery and ossicular reconstruction. METHODS Seventeen temporal bone models was analyzed under different electromechanical stimulations. Scanning laser Doppler interferometry was used to measure the differences in sound conductivity due to the piston and the long process of the incus being crimped to a different degree. RESULTS The degree of crimping of the piston to long process of the incus was defined as either tight,loose or none. The classification was done by three physicians using endoscopic and scanning electron microscopic images. There was no significant disagreement among the doctors. Under 500 mV,800 mV,and 1200 mV of electromechanical stimulations,the degree of sound conductivity between the long process of the incus and piston was determined by scanning laser Doppler interferometry. A computer algorithm was developed in order to simulate acoustic stimulation by electromechanical stimulation. It has been found that the sound transmission loss was 2 dB,which was similar to the sound transmission loss of 3 dB within the incudostapedial joint. But the degree of crimping resulted in variabilities in this number. While the greatest loss was 28 dB,the average loss was 10 dB. CONCLUSION The optimal crimping between the long process of the incus and piston is tight,as it results in less sound transmission loss compared to the physiologic transmission loss within the incudostapedial joint.

OBJECTIVETo assess the amount of sound transmission loss in order to deeply understand the mechanism of middle ear sound transmission for ossicular reconstruction and for guidance of crimping between prosthesis and stapes on sound transmission in stapes surgery.

METHODSIn order to get a correcting magnetic field 2 temporal bone models was used first. Temporal bone models was developed using 17 human temporal bones from fresh cadavers. To measure the sound transmission properties in the middle ear, 15 temporal bone models were detected by scanning laser Doppler interferometry with acoustical stimulation and electromechanical stimulation. An algorithm was developed to simulate acoustical stimulation with electromechanical stimulation. A sound transmission loss within the incudostapedial joint was detected by electromechanical stimulation in 10 temporal bone models.

RESULTSThe average transmission loss within the incudostapedial joint remained 3 dB over the frequencies detected.

CONCLUSIONSThere was a sound transmission loss within the incudostapedial joint, which was a physiological and protection way.

Acoustic Stimulation ; Aged ; Aged, 80 and over ; Algorithms ; Ear, Middle ; physiology ; Female ; Humans ; Joints ; physiology ; Male ; Middle Aged ; Models, Biological ; Sound ; Temporal Bone ; physiology