Figure - available from: European Archives of Oto-Rhino-Laryngology
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Different types of sinus tympani; a type A sinus tympani; b type B sinus tympani; c type C sinus tympani; FN facial nerve, black arrow—posterior semicircular canal, white asterisk—sinus tympani
Source publication
Background and purpose
Retrofacial approach (RFA) is an access route to sinus tympani (ST) and it is used in cholesteatoma surgery, especially when type C ST is encountered. It may also be used to gain an access to stapedius muscle to assess the evoked stapedius reflex threshold. The primary object of this study was to evaluate the morphology of si...
Citations
... 24 However, reduced sensitivity for cholesteatoma localization in the sinus tympani was observed in this study and confirmed in another study. 25 This might be explained by the small size of retrotympanic subspaces as the sinus tympani, which has a mean width of approximately 2 mm, 26 so that cholesteatoma may not be reliably detected. Furthermore, also slight misregistration in fusion images may result in failure of correct cholesteatoma localization. ...
Objective:
To correlate radiographic evidence of cholesteatoma in the retrotympanum with intraoperative endoscopic findings in cholesteatoma patients and to evaluate the clinical relevance of radiographic evidence of cholesteatoma in the retrotympanum.
Study design:
Case series with chart review.
Setting:
Tertiary referral center.
Methods:
Seventy-six consecutive cases undergoing surgical cholesteatoma removal with preoperative high-resolution computed tomography (HRCT) were enrolled in this study. A retrospective analysis of the medical records was conducted. The extension of cholesteatoma regarding different middle ear subspaces, into the antrum and mastoid were reviewed radiologically in preoperative HRCT and endoscopically from surgical videos. Additionally, facial nerve canal dehiscence, infiltration of the middle cranial fossa, and inner ear involvement were documented.
Results:
Comparison of radiological and endoscopic cholesteatoma extension revealed statistically highly significant overestimation of radiological cholesteatoma extension for all retrotympanic regions (sinus tympani 61.8% vs 19.7%, facial recess 69.7% vs 43.4%, subtympanic sinus 59.2% vs 7.9%, and posterior sinus 72.4% vs 4.0%) and statistically significant overestimation for mesotympanum (82.9% vs 56.6%), hypotympanum (39.5% vs 9.2%), and protympanum (23.7% vs 6.6%). No statistically significant differences were found for epitympanum (98.7% vs 90.8%), antrum (64.5% vs 52.6%), and mastoid (26.3% vs 32.9%). Statistically significant radiological overestimation of facial nerve canal dehiscence (54.0% vs 25.0%) and invasion of tegmen tympani (39.5% vs 19.7%) is reported.
Conclusion:
Radiologic cholesteatoma extension in different middle ear subspaces is overestimated compared to the intraoperative extension. The preoperative relevance of radiological retrotympanic extension might be limited in the choice of approach and transcanal endoscopic approach is always recommended first.
... Hence, estimating the degree of mastoid pneumatization using SS at the level of the LSSC as a reference point during surgical planning can be easily utilized by otologists in analyzing critical areas or structures that might be affected by varying degrees of pneumatization, such as the proximity of the facial nerve as well as the articular eminence of the temporo-mandibular joint (TMJ) to the canal in procedures, such as canaloplasty or subtotal petrosectomy [34,35], as well as approaches to the sinus tympani and its relationship to the facial nerve and posterior semicircular canal (PSCC) [36]. ...
Background
The degree of mastoid pneumatization of the temporal bone (TB) has been implicated in the pathogenesis of TB diseases and surgical implications, and planning of a few otologic surgeries. However, there is lack of consensus in the classification of the degree of pneumatization. This study aimed to suggest a simple, quick, and less-burden classification system for assessing and rating the degree of pneumatization by comparing two levels of TB computed tomographs (CTs) using the SS as a reference in an inter-observer assessment among otologists.
Methods
This was a randomized pilot survey among otologists. A questionnaire consisting of different axial CTs of TB taken at two levels: the level of malleoincudal junction (MIJ) and the level of lateral semicircular canal (LSCC), with different pneumatization patterns, was used to assess participants' impressions of the degree of pneumatization. The terms “hypo-,” “moderate,” “good,” and “hyper-” pneumatization were listed as options to rate their impressions on the degree of mastoid pneumatization of the TB images using the SS as a reference structure. Likert scale was used to assess their level of agreement or disagreement with using SS as a reference in evaluating mastoid pneumatization.
Results
Participants who correctly rated images taken at the level of LSCC according to their respective degree of pneumatization were significantly higher (p < 0.05) regardless of their year of experience compared to those that correctly rated corresponding images taken at the level of MIJ. A 76% positivity in their level of agreement with the use of sigmoid sinus in evaluating mastoid pneumatization was observed on the Likert-scale chart.
Conclusion
Findings from this study suggest that evaluating air cells around the SS at the level of LSCC on CTs could be easier in assessing and classifying the degree of mastoid pneumatization.
... In the second situation, it may expand laterally, surrounding the facial nerve, or medially -inferior to the labyrinth or into the bony space between the crura of the posterior semicircular canal. It is a window and target for retro-facial approach to the tympanic cavity [4]. When the ponticulus is incomplete, the tympanic sinus merges with the posterior tympanic sinus, further increasing its surface area and volume. ...
The development of imaging methods in the last twenty years and the increased availability of high-resolution CT of temporal bones make it possible to analyze the complex anatomy of the insides of the temporal bone in detail with greater accuracy than before. At the same time, advances in middle ear surgery require the surgeon to be familiar with the interpretation of imaging examinations. This approach makes it possible to select the treatment method individually for each patient. It may also contribute to reducing the risk of complications.The article presents a description of the CT examination technique along with a historical outline, as well as the interpretation of the CT examination of temporal bones together with the description of anatomical structures, Particular interest was brought on the middle ear structures and those visible in the CT examination. In addition, anatomical variants are presented that a person viewing the images obtained with this method may encounter.
Objective
The facial sinus is a recess of the lateral retrotympanum located between the chorda tympani (ChT) and facial nerve (FN). Chronic otitis media with cholesteatoma often spreads from the pars flaccida to the facial sinus (FS). In stapedotomy, if an unfavorable ChT type is encountered, there is a need for removal of bone between the ChT and FN. The aim of the study was to assess FSs in adults and children according to Alicandri-Ciufelli classification, to measure FS width and depth in computed tomography scans, evaluate the correlation between measurements and different types of facial sinuses, and provide a clinical context of these findings.
Methods
Cone Beam Computed Tomography (CBCT) of 130 adults and High Resolution Computed Tomography of 140 children were reviewed. The type of facial sinus was assessed according to Alicardi-Ciufelli's classification in different age groups. Width of entrance to facial sinus (FSW) and depth of FS (FSD) were evaluated among age groups.
Results
Type A of FS is dominant in both adult and children populations included in the study. The average depth of FS was 2.31±1.43 mm and 2.01±0.90 in children and adults respectively. The width of FS was 3.99±0.69 and 3.39±0.98 in children and adults respectively. The depth of FS (FSD) presented significant deviations (ANOVA, p<0.05) among all three types and age groups. In 116/540 (21.5%) cases the value of FSD was below 1 mm.
Conclusion
The qualitative classification of facial sinuses into types A, B and C, introduced by Alicandri-Ciufelli and al. is justified by statistically significant differences of depth between individual types of tympanic sinuses. Type A sinuses may be extremely shallow (<1 mm - As) or normal (>1 mm - An). Preoperative assessment of CT scans of the temporal bones gives crucial information about type and size of facial sinus. It may increase the safety of surgeries in this area and play a role in choosing an optimal approach and surgical tools.
