Differences between pre- and post-operative bone conduction threshold changes according to the types of mastoidectomy / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: There have been many studies about elevated bone conduction (BC) thresholds in patients with chronic otitis media (COM) with or without cholesteatoma and the relationships between operative techniques and postoperative changes of BC thresholds. The purposes of this study are evaluation of the effect of chronic otitis media on BC thresholds, the relationships between various operative techniques and postoperative BC threshold changes. MATERIALS AND METHODS: Preoperative BC thresholds in 237 patients with ipsilateral COM were evaluated and pre- and postoperative differences of BC thresholds were compared by each frequency in all patients. The patients were divided into three groups according to the severity of diseases (1) Simple relatively healthy middle ear mucosa and thus only simple mastoidectomy (SM) was done (N=92), (2) Severe mastoidectomy with posterior tympanotomy (ICWM) or open cavity mastoidectomy (OCM) were done because of severe edematous middle ear mucosa, granulation tissues, or poor ventilation (N=89), (3) cholesteatomas (Chole, N=56). RESULTS: Preoperative audiograms revealed a significant relationship between the elevation of BC threshold and the severity of diseases. Postoperative BC thresholds were improved in 49% of SM (13.8 +/- 8.5), 51% of ICWM (13.8 +/- 6.1), and 35% of OCM (14.4 +/- 8.4), maintained in 45% of SM, 37% of ICWM, and 43% of OCM, but worsened in 6% of SM (-8.7 +/- 1.4), 12% of ICWM (-10.9 +/- 5.2), and 22% of OCM (-13.8 +/- 6.0). CONCLUSION: The preoperative BC threshold were maintained or improved in the majority of patients postoperatively. In OCM, more patients were worsened in BC hearing postoperatively than the others.