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.

Keywords::

• Rat
• laser myringotomy
• morphology

Acknowledgments

The authors wish to thank Dr Gregory Margolin, Karolinska University Hospital, for his kind assistance, and Paula Mannström and Mikael Eriksson, Karolinska Institute for their excellent technical assistance. The study was supported by the Center for Clinical Research, Landstinget Västmanland and Helga Hjerpstedts Fond, Sweden, and funds from Karolinska Institute, Sweden.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.