Preoperative predictors of incudal necrosis in chronic suppurative otitis media

Abstract

Objective: To determine the predictive value of preoperative clinical, audiological, and radiological factors in diagnosing incudal necrosis in patients with tubotympanic chronic suppurative otitis media (CSOM). Study Design: Case series with planned data collection. Setting: Tertiary care referral center. Subjects and Methods: Patients older than five years of age diagnosed with tubotympanic CSOM who underwent tympanomastoid surgery were recruited. Findings on otoscopy, x-ray mastoid, pure-tone audiometry, and intraoperative otomicroscopy were recorded. Results: Incus necrosis occurred in 24 (16%) of a total of 150 patients. On bivariate analysis, findings of active ear discharge ( P = 0.01), anterosuperior location of perforation ( P = 0.03), exposure of incudostapedial joint ( P = 0.05), edematous middle ear mucous membrane ( P = 0.05), middle ear granulations ( P = 0.004), foreshortening of the handle of malleus ( P = 0.04), moderate to moderately severe hearing loss (41-70 dB HL) ( P = 0.000), and air-bone gap > 40 dB ( P = 0.001) were found to be associated with incus necrosis. Intraoperative findings of aditus block ( P = 0.001) and mastoid granulations ( P = 0.005) were also found to be significantly associated with incus necrosis. Mastoid pneumatization and perforation size and site were not associated with incus necrosis. On multivariate analysis, only middle ear granulations ( P = 0.04; odds ratio [OR] 3.161; 95% confidence interval [95% CI] 1.087-9.196) and a moderate to moderately severe hearing loss (41-70 dB HL) ( P = 0.03; OR 1.720; CI 1.064-2.782) were found to be significant risk factors. Conclusion: Incus necrosis is best predicted by the presence of middle ear granulations and moderate to moderately severe hearing loss (41-70 dB HL). Knowledge of this information preoperatively can influence surgical decision making and preparedness regarding ossiculoplasty and patient consent.