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

• Published in: Acta oto-laryngologica Vol. 131; no. 5; pp. 480 - 487
• Main Authors: von Unge, Magnus, Hultcrantz, Malou
• Format: Journal Article
• Language: English
• Published: Stockholm Informa Healthcare 01.05.2011; Taylor & Francis; Informa
• Subjects: Animals; Biological and medical sciences; Ear, auditive nerve, cochleovestibular tract, facial nerve: diseases, semeiology; Female; Keratinocytes - physiology; laser myringotomy; Lasers, Solid-State; Medical sciences; Medicin och hälsovetenskap; Microscopy, Electron, Transmission; morphology; Non tumoral diseases; Otorhinolaryngology. Stomatology; Rat; Rats; Rats, Sprague-Dawley; Tympanic Membrane - ultrastructure; Tympanic Membrane Perforation - pathology; Wound Healing; Tympanum; Rat; Middle ear disease; Rodentia; ENT; Tympanum perforation; Vertebrata; Mammalia; Healing agent; Animal; Morphology; Laser; ENT disease; Early; laser myringotomy; Cicatrization
• DOI: 10.3109/00016489.2010.533696
• ISSN: 0001-6489; 1651-2251

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.