Background: A clinical condition known as chronic otitis media (COM) is characterized by tympanic membrane perforation, varying degrees of hearing loss, and otorrhea that lasts for two to six weeks. COM alone or with cholesteatoma may result in ossicular chain discontinuity and ossicular erosion. The hearing restoration procedure includes repairing the eardrum and building the ossicular chain in ears with damaged ossicles. Multiple studies suggest the predictive value of preoperative air-bone gap (ABG) to detect the ossicular chain status can help with proper preoperative planning for surgery.
Objective: To determine the degree of hearing improvement and reduction in ABG after tympanoplasty and to investigate the correlation between preoperative ABG and the status of the ossicular chain during surgery. Study design, setting, and date: This retrospective hospital file-based study was conducted at Aseer Central Hospital, Southern Region, Saudi Arabia, between November 2022 and April 2023. Hospital records of patients who underwent tympanoplasty during 2018-2023 were reviewed. Eighty-five patients were diagnosed with chronic suppurative otitis media (CSOM) between 2018 and 2023. A data collection sheet was employed to record extracted data, including the patient's age, sex, hearing assessment, type of surgical intervention, and outcome. We calculated the average of ABG decibels (dB) by summing the ABG values at 500 Hz, 1000 Hz, and 2000 Hz frequencies and dividing by three.
Results: In the present study, data from 85 patients who underwent tympanoplasty were analyzed. Approximately one-third of the patients were in the age group of 31 to 40 years (25, 29.4%), and 50 (58.8%) of them were females. Chronic medical conditions were observed in 30 (35.3%) patients, with diabetes being reported in 19 (63.3%) of those cases. CSOM was found to be present in the left ear of 47 (56.0%) patients. Among the patients, 25 (29.4%) had subtotal perforations, 12 (14.1%) had marginal perforations, and two (2.4%) had total tympanic membrane perforations. The majority of patients (67, 78.8%) exhibited conductive hearing loss, while the remaining 18 (21.2%) had mixed hearing loss. Of the patients, 13 (15.3%) and 20 (23.5%) had fixed and disrupted ossicular chains, respectively. In terms of ossicular disruption, incudostapedial joint (ISJ) fixing (21.2%), fixed stapes (18.2%), and ISJ dislocation (18.2%) were the most prevalent kinds. Prior to operations, the mean ± SD of ABG was 22.6 ± 7.5. ABG values were 19.0 ± 9.3 on average after surgery. The statistical difference between pre- and postoperative ABG was statistically significant (paired t-test, p = 0.007), with a mean difference of -3.7. There were no significant differences between the different statuses of ossicular chains and the type of tympanic membrane perforation.
Conclusion: This study suggests that the degree of preoperative ABG (dB) is a valuable predictor of intraoperative ossicular chain status and can aid in preoperative planning for ossicular chain reconstruction. Furthermore, the study found that the type of tympanic membrane perforation preoperatively is not a reliable indicator of the ossicular chain status. Finally, tympanoplasty is considered a beneficial surgical procedure with a significant improvement in hearing status postoperatively.
Keywords: abg: air-bone gap; chronic suppurative otitis media; csom: chronic suppurative otitis media; ossicles; ossicular chain; tympanic membrane perforation; tympanoplasty.
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