Comparison of the underlay and over-underlay tympanoplasty: A randomized, double-blind controlled trial

We aimed to compare the graft success rate and hearing outcomes in patients with large tympanic membrane (TM) perforation in underlay and over-underlay approaches.

This is a prospective double-blind randomized controlled clinical trial with a parallel design. Patients aged 15-75 years old with large TM perforation (more than 50% of TM) who operated at Khalili hospital affiliated with Shiraz University of Medical Science, Iran, were enrolled. Exclusion criteria were recent otorrhea, revision surgery, and pathologic intraoperative findings such as the presence of cholesteatoma, cholesterol granuloma, ear canal polyp, or damaged ossicle. In the first group, the underlay method and in the second group over-underlay method were performed. Graft success rate, atelectasis, and audiology outcomes were evaluated after 6 months.

The investigation was conducted on 84 patients in the underlay and 67 patients in the over-underlay group. Although there was a higher rate of graft failure (9%) in the over-underlay group in comparison with the underlay group (4.8%), the difference was not statistically significant (p-value = .34). No atelectasis was seen in both group. Although, between-groups comparison of the preoperative and postoperative speech reception thresholds (SRT) and air-bone gaps (ABG) values showed statistically significantly lower SRT and ABG in the over-underlay technique, the difference was clinically negligible.

Both techniques provide the same graft success rate, but SRT and ABG were significantly lower in the over-underlay technique after the operation.

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