Healing of tympanic membrane after myringotomy during Streptococcus pneumoniae otitis media: An otomicroscopic and histologic study in the rat

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The purpose of our study was to elucidate the course of healing of the tympanic membrane (TM) when myringotomy was performed during acute otitis media. The early and long-lasting structural changes of the TM were studied in an animal model. Rats were inoculated with Streptococcus pneumoniae (PnC) type 3 in the bulla. When the infection was manifest, myringotomy was performed. On days 4 and 12, and 3 and 6 months after myringotomy, the TM status was checked by otomicroscopy and TMs were prepared for light and electron microscopy. Comparison was made with PnC-infected TMs that were not perforated, as well as myringotomized noninfected TMs. The infection resolved more slowly in myringotomized ears compared to PnC-infected ears that were left untouched. After 6 months, the pars tensa of the myringotomized infected ears was thickened and showed a disorganized collagen structure, compared with myringotomized noninfected ears, in which TMs were normalized. The PnC- infected TMs without myringotomy were completely normalized after 2 months. We conclude that a combination of bacterial infection and myringotomy causes long-lasting changes in TM structure. This impaired structure of the connective tissue could be of importance in chronic middle ear disease as a presumptive site for retraction and perforation of the TM.


Enheter & grupper
Externa organisationer
  • Umeå University

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Oto-rino-laryngologi


Sidor (från-till)397-404
Antal sidor8
TidskriftAnnals of Otology, Rhinology and Laryngology
StatusPublished - 1996 maj 1
Peer review utfördJa