Application of Belfast 15/30 dB Rule of Thumb in Assessing Hearing Benefit in Middle Ear Reconstructive Surgery.

The objective of this study is to assess the concordance between Belfast 15/30 dB rule of thumb and subjective hearing benefit in middle ear reconstruction surgery. A total of 105 cases of chronic otitis media (COM) (both mucosal and squamosal type) with conductive hearing loss and who underwent middle ear reconstructive surgery during the study period from January 2019 to January 2022 were included. All cases were followed up at 6 week and at 3 months of postoperative duration for subjective assessment of hearing with questionnaire and pure tone audiometry as per standard of care and correlated with Belfast 15/30 dB rule of thumb. Concordance with Belfast rule of thumb was seen in 73.4% cases of both mucosal and squamosal type of COM. Belfast 15/30 dB rule of thumb is a valuable and useful tool to predict hearing benefit following middle ear reconstructive surgery, but, it suffers from the disadvantages of all or none phenomenon and it does not grade the level of hearing improvement. The prediction of postoperative subjective hearing with this Belfast rule of thumb is more reliable in mucosal type of COM than in squamosal type of COM.