Round window otosclerosis: radiologic classification and clinical correlations

Area of Science:

• Otolaryngology
• Radiology
• Medical Imaging

Background:

• Otosclerosis is a common cause of conductive hearing loss.
• Round window involvement in otosclerosis can affect surgical outcomes.
• A standardized classification for round window otosclerosis is needed.

Purpose of the Study:

• To develop a radiologic classification system for the severity of round window involvement in otosclerosis.
• To evaluate the impact of different classes of round window involvement on hearing and stapes surgery outcomes.

Main Methods:

• Retrospective review of computed tomographic (CT) scans from 930 ears with otosclerosis.
• Identification of 121 ears with round window involvement, with 41 ears without pericochlear involvement as the primary study group.
• Classification of round window involvement into five grades (RW-I to RW-V) based on CT findings, and analysis of hearing measures and surgical outcomes.

Main Results:

• 17.1%, 31.7%, 34.1%, and 17.1% of the 41 ears were classified as RW-I, RW-II, RW-III, and RW-IV, respectively.
• No significant difference in hearing or air-bone gap (ABG) after stapes surgery was observed for RW-I and RW-II groups compared to controls.
• RW-III and RW-IV groups showed significantly poorer hearing and larger postoperative ABG, with RW-IV having the most severe hearing loss and worst surgical outcomes (p ≤ 0.001).

Conclusions:

• The proposed radiologic classification for round window otosclerosis is a valuable clinical tool.
• Classes RW-I and RW-II have no significant clinical impact on stapes surgery.
• Patients with RW-III and RW-IV otosclerosis face poorer hearing outcomes and residual air-bone gaps after stapes surgery, necessitating careful counseling.