The early events in the healing of laser-produced tympanic membrane perforation

Abstract

Conclusion: An immense keratinocyte activity with high cell turnover produced keratin that was delivered to span the perforation. The perforation size did not define the time to closure. Objectives: Most tympanic membrane perforations heal spontaneously, whereas a fraction remains patent. A simple, nonsurgical cure for chronic perforations is required. Better understanding of the healing processes might enable the development of a simple medical cure. Therefore the structural events of the healing process were investigated, as well as its dynamics, by comparing perforation size with time to closure. Methods: Twenty-four Sprague-Dawley rats were myringotomized with a KTP laser. Different perforation sizes were produced. The ‘early closing picture’ was assessed with otomicroscopy and light and transmission electron microscopy at between 1 h and 2 weeks after myringotomy and perforation size was monitored until closure. Results: In all, 40% of the perforations were closed after 8 days and 89% at 12 days. The closing time did not directly correlate with perforation size. A wave of keratinocytes migrates towards the perforation site and disintegrates to form a keratin mass that eventually spans the perforation. A less intense activity is present near the annulus. The origin of the epithelial migration is probably regenerative centers.