Early structural tympanic membrane reactions to myringotomy: A study in an acute otitis media model

• Type: Article in International Scientific Journal
• Date: 2002

Authors

Jorge Spratley (Author) Other; Hellstrom, S (Author) Other; Eriksson, PO (Author) Other; Pais Clemente, M (Author) Other

Journal

Title: Acta Oto-Laryngologica

Vol. 122

Pages: 479-487

ISSN: 0001-6489

Publisher: Taylor & Francis

Indexing

ISI Web of Knowledge - 16 Citations

Scopus - 16 Citations

Other information

Authenticus ID: P-000-QN2

DOI: 10.1080/00016480260092264

Abstract (EN): Myringotomy (Myr) is one of the most frequently performed surgical procedures in children. However, events occurring in the early phases, i.e. a matter of hours, following Myr in the acute otitis media (AOM) model have not been described. The aim of the present study was to evaluate the early otomicroscopic and histopathologic reactions of the tympanic membrane (TM) after Myr during the course of AOM (AOM-Myr). The left tympanic bulla from 36 healthy Sprague-Dawley rats was inoculated with Streptococcus pneumonia e type 3. Forty-eight h later, at Day 0, 4 randomized animals were immediately sacrificed and the remaining animals were treated with bilateral Myr. Otomicroscopy and sacrifices were performed in series of 4 animals at 3, 6, 9, 12, 24 and 48 h, and 4 and 7 days. The AOM-Myr TMs were compared to non-infected Myr TMs (non-AOM-Myr). The TMs were then dissected free and routinely processed for light and electron microscopy. AOM developed in all inoculated ears at Day 0. In the pars tensa of the AOM-Myr TMs the reaction of the keratinocyte layer of the perforation border was already evident at 6 h. The lamina propria exhibited a strong inflammatory reaction, which became more organized from 12 h onwards. At Day 4 the perforations were closed in three-quarters of cases. At Day 7 all perforations were healed with a distorted scar. In the non-AOM Myr TMs a strong degranulation of mast cells and edema were found in the pars flaccida at 6 h. A keratin spur at the perforation border was not seen until 24 h. All perforations were patent on Day 7 and myringosclerotic deposits were abundant in these TMs. The infected TMs regenerated fast er and closed their perforations at an earlier stage. These findings favor the hypothesis that there is a low risk of chronic perforations when myringotomizing AOM TMs.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9