Capabilities of Mdct of the Temporal Bone Structures Before Stapes Surgery

Abstract

Introduction: The overall results of stapes surgery considerably depend on the anatomy peculiarities of complicated temporal bone’s structure. Materials and methods: 37 persons (63 ears) with otosclerosis participated in the study. All patients have been examined by microotoscopy, audiologic tests, MDCT. The niche of vestibular window was assessed in all ears on the following criteria: the width and form of the niche, the presence and absence of overhanging of facial nerve canal and promontorium over the vestibular window, the width of the stapes footplate, stapes cruses width, distance to the internal wall of vestibule. All 63 ears underwent stapes surgery. Results: Overhanging of facial nerve canal over the vestibular window were observed in 14 ears, overhanging of a promontorium – in 9 ears, protrusion of facial nerve canal – in 6 ears. Wide niche was observed in 45 ears, narrow–in 18. The rectangular shape was observed in 18 ears, trapezoid–in 32, triangular–in 13. Thickening of a stapes footplate observed in all 53 ears. Thickening of stapes cruses noted in 11 ears. Distance to the internal wall of a vestibule less than 2мм noted in 5 ears, more than 2мм-in 58. The stapedoplasty was performed in 63 ears: 44 the „standard“ piston stapedoplasty; 14 the „aim“ piston stapedoplasty; 5 the „standard“ piston stapedoplasty with stapedectomy. Sensitivity of MDCT was 95,2%, specificity–98,4%, accuracy–96,8%. Conclusion: The MDCT-criteria allows estimating the complexity of the surgery, to plan surgery thoroughly, to predict the outcome.