Analysis of tympanic sinus shape for purposes of intraoperative hearing monitoring: a microCT study

Purpose Sinus tympani is the space in the retrotympanum, with variable morphology. Computed tomography is a common tool to investigate sinus tympani anatomy. During cochlear implantation or tympanoplasty, electrocochleography can be used for hearing monitoring. In such a surgical strategy the electrode is placed in the round window’s region throughout posterior tympanotomy. Common accessible needle-shaped electrodes using is difficult in achieving intraoperative stabilization. The aim of the study is to assess the dimensions and shape of sinus tympani, basing on the micro computed tomography scans for purposes of establishing the possible new electrocochleography electrode shape. Materials and methods Sixteen fresh frozen cadaveric temporal bones were dissected. MicroCT measurements included the depth and the width of sinus tympani, width of facial canal with stapedius muscle chamber. Obtained data were analyzed statistically with the use of RStudio 1.3.959 software. Results The highest average width of sinus tympani amounted for 2.68 mm, depth measured at the round window plane for 3.19 mm. Width of facial canal with stapedius muscle chamber highest average values at the round window plane- 3.32 mm. The lowest average minimum and maximum values were calculated at the 1 mm above the round window plane. The highest average posterior tympanotomy width was 2.91 mm. Conclusions The shape of the tympanic sinus is like a trough with the narrowest and deepest dimensions in the middle part. The ST shape and dimensions should be taken into account in constructing the ECochG electrode, designed for optimal placement through posterior tympanotomy approach.

A study to evaluate and compare the outcomes of endoscope versus microscope assisted myringoplasty

<p class="abstract"><strong>Background:</strong> In microscope assisted middle ear procedures surgeons can only observe the parts of the tympanic cavity, the hidden areas, such as the facial recess and sinus tympani, would not be visualised which needs to be exposed for performing tympanoplasty. The aim of the study was to compare the outcomes of microscope versus endoscope assisted myringoplasties in terms of duration of the procedure, graft take up, improvement in hearing and incidence of any complications.</p><p class="abstract"><strong>Methods:</strong> A prospective comparative study was conducted for a period of one year. A total of 72 patients with CSOM were randomised into two groups of 36 each. Group A patients (n=36) underwent traditional myringoplasty under a microscope and group B patients (n=36) endoscopic assisted myringoplasty was performed. Post-operatively all the patients were followed up for a period of one year. During the follow-up period patients were assessed for the graft take up, hearing improvement, incidence of complications and recurrence rate between the two groups.</p><p class="abstract"><strong>Results:</strong> Successful graft uptake was observed in 88.8% among patients underwent microscope assisted myringoplasty and it was 94.4% in endoscopic assisted myringoplasty. The mean duration of surgery was 123 mins in microscopic assisted group compared to 92 mins in endoscopic assisted group and the difference was found to be statistically significant. Similarly, the cosmetic results and the post-operative pain were more favorable for endoscopic assisted group than microscopic assisted group and the difference was found to be statistically significant.</p><p class="abstract"><strong>Conclusions:</strong> Enoscopic assisted procedure could be considered as a better alternative for microscopic assisted myringoplasty.</p>

Role of otoendoscope as a preoperative tool in tympanoplasty

<p class="abstract"><strong>Background:</strong> Chronic suppurative otitis media (CSOM) is one of the common causes for hearing impairment and disability. Despite continuous technical improvement, the basic optical principles and their limitations have remained the same over the past three decades. This study aimed at visualizing and evaluating the middle ear structures with the aid of 0 and 30-degree otoendoscopes preoperatively in cases of chronic suppurative otitis media.</p><p class="abstract"><strong>Methods:</strong> In this prospective study, 70 patients (40 females and 30 males) above the age of 10 years with CSOM were subjected to otoendoscopy using 0- and 30-degree endoscopes. The various middle ear structures and hidden spaces like facial recess, sinus tympani, hypotympanum were visualized preoperatively. </p><p class="abstract"><strong>Results:</strong> Middle ear structures and blind niches were better evaluated preoperatively using 0 and 30-degree otoendoscopes and a definitive operative plan was formulated.</p><p class="abstract"><strong>Conclusions:</strong> Otoendoscopy provided a significant better visualization of all the middle ear structures and various hidden spaces.</p>

Supratubal recess and sinus tympani: CT analysis of middle ear hidden areas

Background High-resolution computed tomography (HRCT) magnifies the role of preoperative imaging for detailed middle ear anatomy particularly its hidden area. The purpose of the current study was to assess the sinus tympani (ST) and supratubal recess (STR) by HRCT, to create CT classification of the STR depth, and to study the relationship between ST types and the new STR grades. Results In HRCT of non-pathological temporal bones of 100 subjects (200 ears), measurements of the STR and ST were calculated, registered, and analyzed. The depth of the STR was classified into grade 1 with depth less than 3 mm, grade 2 with depth ranged between 3 and 5 mm, and grade 3 with depth more than 5 mm. The mean STR length, width, and height were 4.17 ± 0.86, 3.55 ± 0.65, and 3.64 ± 0.7 mm, respectively, while the ST mean length and width of were 2.52 ± 0.5 and 1.82 ± 0.78 mm, respectively, without significant differences between either sexes or sided. The ST types were found to be type A in 56 ears (28%), type B in 142 ears (71%), and type C in 2 ears (1%). The STR grading was grade 1 in 12 ears (6%), grade 2 in 160 ears (80%), and grade 3 in 28 ears (14%) without significant relationship between ST types and STR grading (P = 0.3). Conclusion The current study provided reliable and applicable methods of CT assessment of STR and ST that can help to predict the degree of surgical visibility of the ST and STR during ear surgery.

HRCT imaging of acquired cholesteatoma: a pictorial review

Chronically discharging ear is a common cause of morbidity in developing countries, and it is also associated with intratemporal and intracranial complications. The surgeon is often able to detect the disease. However, cholesteatoma in the “hidden areas” like anterior epitympanic recess and sinus tympani can be missed. Facial nerve involvement and cholesteatomatous erosion of the bony labyrinth are dreaded complications, the extent of which cannot be assessed completely on clinical examination. Adding to the complexity are the various variations in anatomy like high riding jugular bulb and aberrant internal carotid artery which could lead to catastrophic complications during surgery if left undetected preoperatively. HRCT temporal bone is useful to detect the extent of the disease, various complications, and guide the surgeon for pre-operative planning. In this review, we go through the various HRCT imaging features of acquired cholesteatoma, a reporting template, and a few words about imaging of the post-operative ear.

Evaluating the role of otoendoscope in cholesteatoma surgery

<p class="abstract"><strong>Background:</strong> Endoscope assisted ear surgery (EAES) reduces the chances of residual cholesteatomas as compared to the conventional microscopic technique, primarily because of the direct visualization of sites where residual cholesteatoma is common, which is often missed out during the traditional microscopic surgical procedure. The aim of the study was to evaluate the hidden areas of middle ear using endoscopes during the conventional microscopic cholesteatoma surgery.</p><p class="abstract"><strong>Methods:</strong> The present prospective study was carried out in the Dept. of Otorhinolaryngology and Head &amp; Neck Surgery, Shri Mata Vaishno Devi Narayana Superspeciality Hospital, Katra, Jammu for a period of one year during which a total of 20 patients of acquired cholesteatoma who underwent conventional microscopic surgery were followed by oto-endoscope assisted examination were enrolled. </p><p class="abstract"><strong>Results:</strong> Otoendoscope was used in all the surgeries to look for residual cholesteatoma in the hidden areas like protympanum, sinus tympani and anterior attic. An overall incidence of cholesteatoma observed and removed from hidden areas using otoendoscope was recorded to be 30% in the present study.</p><p class="abstract"><strong>Conclusions:</strong> Microscopic ear surgery assisted with oto-endoscope allows a better visualization of the extent of cholesteatoma and thus improved eradication of residual/recurrent disease from the hidden areas of middle ear such as facial recess, sinus tympani, anterior epitympanic space, protympanum and hypotympanum.</p>