Association of Middle Ear Risk Index with Anatomical and Audiological Outcomes Following Tympanoplasty: A Prospective Observational Study

Abstract

Background: Chronic middle-ear disease may cause tympanic membrane perforation, chronic inflammation, ossicular damage, and conductive hearing loss, thereby affecting the outcome of tympanoplasty. The Middle Ear Risk Index (MERI) combines adverse middle-ear factors into a composite score and may assist in assessing disease severity and postoperative risk.

Objective: To evaluate the association between MERI severity and anatomical and audiological outcomes following tympanoplasty and tympanomastoid surgery and to assess its relationship with the extent of surgical intervention.

Methods: This prospective observational cohort study was conducted in the Department of Otorhinolaryngology, Hind Institute of Medical Sciences, Sitapur, Uttar Pradesh, from July 2023 to August 2024. A total of 111 patients were enrolled, of whom 88 had postoperative outcome data and were included in the final analysis. MERI was categorized as mild (1–3), moderate (4–6), or severe (7–12). The principal anatomical outcome was graft uptake at 6 months. Functional outcome was assessed using postoperative air–bone gap (ABG) and ABG gain. Categorical variables were analyzed using chi-square tests, within-group audiological changes using paired t-tests, and differences in ABG gain across MERI categories using one-way analysis of variance.

Results: Among 88 analyzed patients, 19 (21.6%) had mild, 37 (42.0%) moderate, and 32 (36.4%) severe MERI. Six-month graft uptake was 94.7%, 81.0%, and 68.7% in the mild, moderate, and severe groups, respectively; the categorical association was not statistically significant (χ²=5.04, p=0.080). Mean 6-month ABG gain was 17.7, 16.1, and 13.9 dB in the mild, moderate, and severe groups, respectively, with a significant between-group difference (F=32.24, p≈3.8×10⁻¹¹). MERI category was also significantly associated with the extent of surgical intervention (χ²=21.44, p=0.002).

Conclusion: Increasing MERI severity was associated with greater surgical complexity and a progressive reduction in postoperative hearing improvement. Graft uptake also showed a clinically relevant decline with increasing MERI, although the categorical association did not reach statistical significance. MERI may therefore be useful as a structured component of preoperative assessment and patient counselling, while larger multicentre studies with longer follow-up and multivariable analysis are needed to establish its independent prognostic value.