Clinical study of correlation between preoperative findings of HRCT with intraoperative findings of cholesteatoma in cases of CSOM

Abstract

Among patients attending to ENT OPD, chronic suppurative otitis media (CSOM) is one of the common conditions. Mastoid, middle ear surgeries are difficult at times because, the CSOM can be associated with complications; the temporal bone accommodates vital structures (internal carotid artery, facial nerve, jugular bulb etc.) and its anatomical variations. In this study, we planned to investigate the use of preoperative HRCT scan to assess the pathology, extent of the disease, middle ear structures, and presence of cholesteatoma and also to compare with intra operative findings. Materials and Methods: The HRCT findings of 40 patients with CSOM with cholesteatoma were compared with operative findings. CT scan was performed with Seimens Somatom emotion 6 scanner. With the help of HRCT status of the middle ear structures (ossicles, scutum, facial nerve canal and tegmen tympani), semicircular canals and sigmoid plate were assessed and compared with operative findings. Correlation between radiological and intra-operative findings was calculated. Results: A good radio surgical correlation is seen in CSOM with cholesteatoma for status of most middle and inner ear structures except for the integrity of the facial canal. A poor radiosurgical correlation was observed for differentiating cholesteatoma from chronic mucosal thickening as the underlying pathology in cases with CSOM. HRCT was found to be sensitive in detecting erosions of incus(85%), stapes(82.3%), scutum(91.67%), sigmoid plate(100%) and mastoid cortex(100%) whereas less sensitive in erosions of malleus (68.75%), tegmen(32.6%), semicircular canal(71.4%) and facial canal(53.3%). 100% specificity was obtained for erosions of malleus, incus, scutum, sinus plate and mastoid cortex whereas it is relatively less specific for erosions of facial canal(84%) and tegmen(81%). Interpretation and Conclusion: HRCT of temporal bone has a definitive role in pre-operative assessment of CSOM with cholesteatoma as it helps in assessing the extent of the disease and integrity of most of the middle ear structures. Keywords: CSOM, HRCT, Cholesteatoma, Radiosurgical correlation, Temporal bone