Minimally invasive inlay and underlay tympanoplasty

Abstract 

Purpose

The objective of this study is to understand the outcome of minimally invasive topical anesthetized transcanal inlay and underlay tympanoplasty, and to compare these 2 procedures in hearing result, take rate, perioperative pain, and operation time.

Materials and methods

This is a retrospective study conducted from September 2003 to December 2006. Forty-eight tympanoplasty in 46 patients, 28 inlay and 20 underlay procedures, with small- to medium-sized tympanic membrane perforations without middle ear lesion, were studied in a tertiary referral center. Interventions included otologic examination, perioperative hearing evaluation, local anesthetized transcanal inlay, or underlay tympanoplasty. The outcome measurements were the following: the take rate and audiometric result at the last follow-up visit, perioperative pain, and duration of surgery. The statistical methods used were t test, Mann-Whitney U test, χ² test, and Fisher exact test.

Results

The take rate were 82.1% in the inlay group and 85% in the underlay group, without significant difference (P = .79) at the last follow-up visit. Air-bone gap closure was 6.3 ± 2.5 dB in the inlay group and 9.3 ± 3.2 dB in the underlay (P = .07). Linear analogue scale of perioperative pain was lower in the inlay group with significance (1.7 ± 1.2 in the inlay and 4.6 ± 1.9 in the underlay group, P < .001). The duration of the surgery was significantly shorter in the inlay group (31.8 ± 13.9 minutes for the inlay group and 75.9 ± 14.6 minutes for the underlay group, P < .001).

Conclusions

Minimally invasive topically anesthetized transcanal tympanoplasty provides satisfactory surgical and audiometric outcome both in inlay and underlay procedures. The take rate and extent of hearing recovery are similar in both groups. However, inlay tympanoplasty is superior to transcanal tympanoplasty because of less discomfort and shorter operation time.