Effect of myringoplasty on inner ear function

Effect of myringoplasty on inner ear function
Reviewed by: Ahmed A Saada
May/Jun 2011 (Vol 20 No 2)

This is an interesting prospective study that describes bone threshold changes after myringoplasty, thus reflecting the effect of such a procedure on inner ear function. Eligible subjects included 134 patients who underwent primary underlay type I tympanoplasty (myringoplasty). Bone conduction thresholds were determined before surgery and 6-12 months postoperatively. Details of the surgical procedure and audiological testing are described; and several variables were considered such as possible ossicular chain trauma, cochlear dysfunction, perforation size, presence of tympanic granulation tissue, myringosclerosis or tympanosclerosis, ossicular chain fixation and external canal drilling. A transcanal approach was used in 59% of cases, whereas a postauricular approach was used in the remaining 41%. There were no significant differences in preoperative threshold by all variables except ossicular chain fixation, granulation tissue and tympanosclerosis. Postoperatively, the only significant differences were noted by perforation size, ossicular chain fixation, surgical approach and external canal drilling. Details of such differences in bone conduction threshold for each frequency tested are displayed in tables. Mechanisms of cochlear damage in cases of otitis media are discussed, including the role of endogenous and exogenous substances. However, other factors that may play a role in bone conduction hearing impairment are thoroughly analysed. In conclusion, the authors observed statistically significant evidence that mechanical factors are associated with poorer bone conduction thresholds. Moreover, they stated that anatomically successful myringoplasty can slightly improve bone conduction with minimal risk of impairment.
Reference
Inner ear function following underlay myringoplasty.
Redaelli de Zinis LO, Cottelli M, Koka M.
AUDIOLOGY & NEUROTOLOGY
2010;15:149-5
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