Study of malleus as a prognostic indicator on hearing outcomes after tympanomastoid surgery: a prospective observational study

• Mishal Ibji,*  
• Poonam Khairnar,  
• Kamalika Purkayastha Roy,  
• Santosh Mane

Abstract

Background: Tympanomastoid surgery comprises a range of surgeries (cortical, radical, modified radical). Pre-operative auditory deficit in a patient with cholesteatoma may be correlated with ossicular chain status. The incus is often expected to be eroded, which may not be true for the malleus. The presence of malleus and it’s significance on the post-operative needs to be studied further. Aim and objective: The purpose of our study is to determine the effect of intraoperative status of malleus on the post-operative hearing outcomes of patients undergoing canal wall-down mastoidectomy. Material and Methods: A prospective observational study of 24 patients was conducted, where pre-operatively pure tone audiometry (PTA) was performed. Intraoperatively, the status of malleus was noted. Canal wall down mastoidectomy was done. Post-operative PTA was recorded after 3 months and both audiograms compared. Results: An air bone gap (ABG) of less than 20dB post-operatively was considered significant functional improvement. In patients with a preserved malleus, mean improvement was 25.2dB (±9.8), whereas patients in whom malleus was remove had mean 16.8dB (±10.49) improvement. Similar results were found by Lu et al, Blom et al and Haberman et al. Haberman et al theorised the concentration of sound waves and preservation of middle ear volume as a contributing factor to the results. Conclusion: Hence it was concluded that relatively better post-operative audiological outcomes were obtained when malleus was present/preserved intraoperatively.

Keywords

Malleus, pure tone audiometry, Canal wall down mastoidectomy, air bone gap