Variability of the retrotympanum and its association with mastoid pneumatization in cholesteatoma patients

Abstract

Purpose This study aimed to investigate the variability of the retrotympanum in patients undergoing surgical treatment for cholesteatoma. Methods We included 59 ears of patients undergoing middle ear surgery for cholesteatoma who had preoperative computed tomography scans. A retrospective analysis of the medical records was conducted. The sinus tympani (ST), subtympanic sinus (STS) and facial recess (FR) were classified into types A–C based on the relationship of their extension to the facial nerve. The mastoid and petrous apex were assessed and categorized as normal pneumatized or sclerotic. Results Type A extension was the most frequently found in all sinuses (ST 64%, FR 77%, STS 69%), Type B extension was found more often in ST (34%) and STS (24%) than in FR (15%). A very deep extension was found only rarely (ST 2%, FR 8%, STS 7%). A sclerotic mastoid was found in 67% of cases. Those cases showed a statistically significant difference regarding retrotympanum pneumatization when compared with normal mastoid. Conclusion The most frequent variant of retrotympanic pneumatization in relation to the facial nerve was type A in all subsites in cholesteatoma patients. The variability among patients with cholesteatoma is different to previously published results in healthy subjects. Moreover, the pneumatization of the retrotympanum is associated with mastoid pneumatization.

A micro-computed tomography study of the sinus tympani variation in humans

“…The present study revealed that both the shape of the ST and its interior surface configuration vary considerably amongst human adults. The factors affecting the shape and volume of the ST still remain unclear, however degree of the temporal bone pneumatization is regarded as one of the physiological reasons that can affect the retrotympanum, as well as the ST itself [10,26].…”

Accuracy of High‐Resolution Computed Tomography Compared to High‐Definition Ear Endoscopy to Assess Cholesteatoma Extension

“…This might be explained due to the fact that retrotympanic pneumatization in cholesteatoma patients is most often a type A configuration and therefore amenable to an endoscopic approach. 29 Thus, in consideration of the overestimated radiologic retrotympanic extension, only meticulous intraoperative evaluation of cholesteatoma extension into retrotympanic subspaces can lead to the decision for a retrofacial approach. In particular, preoperative radiologic disease extension into retrotympanic subsites does not provide reliable information about intraoperative cholesteatoma extension in the retrotympanum.…”

“…Despite this potential limitation for transcanal endoscopic approach to the retrotympanum, no conversion to a retrofacial approach for complete cholesteatoma removal was necessary for our cohort. This might be explained due to the fact that retrotympanic pneumatization in cholesteatoma patients is most often a type A configuration and therefore amenable to an endoscopic approach 29 . Thus, in consideration of the overestimated radiologic retrotympanic extension, only meticulous intraoperative evaluation of cholesteatoma extension into retrotympanic subspaces can lead to the decision for a retrofacial approach.…”

Sinus tympani revisited for planning retrofacial approach—radiologic study in pneumatized temporal bones and its surgical implications

“…Lately, Hool et al found that ST type A may be of higher prevalence in cholesteatoma patients. That is why one has to remember that impaired pneumatization of the mastoid may be associated with a less pneumatized retrotympanum [ 30 ]. As our group of temporal bones was pneumatized, well-aerated only, we wish that the measurements done are to compared with further studies, where diploic and sclerotic mastoids are included.…”