Mastoid obliteration with hydroxyapatite-the value of high resolution CT scanning in detecting recurrent cholesteatoma

Abstract

Mastoid obliteration carries a risk of enclosing cholesteatoma within the mastoid cavity. Using temporal bones obliterated with either muscle or hydroxyapatite granules, the value of high resolution CT scanning in the early detection of 'epithelial pearls' was studied. The results showed that scanning was effective in detecting small epithelial pearls within the cavity obliterated with hydroxyapatite, but not so effective when muscle was used. This is explained by the difference in the CT density between epidermoid cysts and hydroxyapatite allowing the cysts (dark shadows) to be identified easily within a white background. The authors also studied scans performed on 31 ears following mastoid obliteration with hydroxyapatite. There was no residual cholesteatoma in the obliterated area but there was an area of abnormality identified within the obliterated area in one patient due to a cholesterol granuloma.

Long-term follow up after bony mastoid and epitympanic obliteration: radiological findings

“…Although it may take years, small cholesteatoma pearls may eventually become detectable in bone-obliterated mastoids by high resolution CT, appearing as punched-out lesions in the bone density. 8 However, high resolution CT cannot differentiate cholesteatoma from other soft tissues such as scar tissue, cholesterol granuloma, granulation tissue or fluid. Therefore, high resolution CT has a low sensitivity and specificity for cholesteatoma.…”

“…Until recently, high resolution CT was the imaging technique of choice for post-operative follow-up evaluation of mastoids undergoing bony obliteration. 7,8 High resolution CT using bone window settings is considered the method of choice for examination of the middle-ear structures. It provides excellent contrast between osseous structures, air and soft tissues, and it has a high spatial resolution.…”

“…7,8 High resolution CT is characterised by a low sensitivity and specificity for cholesteatoma, and cannot differentiate cholesteatoma from other soft tissues. Recently, non-echo-planar, diffusion-weighted MRI sequences have proven their value in detecting acquired, congenital and residual cholesteatoma down to a size of 2 mm.…”

Mastoid and Epitympanic Bony Obliteration in Pediatric Cholesteatoma

“…Adequate imaging follow-up of obliterated mastoids is necessary to prevent late complications when residual cholesteatoma remains buried in the bony obliterated mastoid. HRCT has been shown to be very effective in excluding and detecting small pearls in obliterated mastoids, presenting as punched-out lesions in the dens bone (24,25). However, in the case of associated opacified lesions, further characterization of the lesion by MRI will be necessary.…”

The modern approaches to the treatment of chronic suppurative otitis with cholesteatoma

“…к выполнению аттико-антро-мастоидотомии с облитерацией паратимпанальных пространств [6,[11][12][13]. Существует множество разных методик облитерации мастоидальной полости, аттика и адитуса: аутокостью, аутохрящом, фасцией височной мышцы, различными биологически инертными синтети-ческими и другими материалами [14,15].…”