Tympanic Orifice Research Articles

Evaluation of eustachian tube and mastoid parameters in chronic otitis media: A computed tomography-based study

Objectives: The study aimed to understand the causes of chronic otitis media (COM) with unilateral or bilateral cholesteatoma by examining the eustachian tube (ET) and mastoid ventilation from preoperative high-resolution temporal computed tomography (HRTCT) scans. Patients and Methods: In this retrospective case-control study, COM patients with cholesteatoma who underwent preoperative HRTCT scanning between January 2021 and December 2023 were analyzed. The study included 102 ears of 51 participants (31 males, 20 females; mean age: 35.7±14.0 years; range, 18 to 65 years). The participants were divided into three groups, each with 17 individuals: unilateral COM with cholesteatoma, bilateral COM with cholesteatoma, and a healthy control group. Variables, including Reid plane-ET angle, tubotympanic angle (TTA), ET length, ET tympanic orifice and isthmus widths, and mastoid ventilation type and volume, were examined in CT images. Results: The mean left TTA (p=0.045) was higher in the unilateral cholesteatoma group compared to the control group (148.88±5.30 and 144.24±6.51, respectively; p=0.045). The bilateral cholesteatoma group exhibited higher values for right and left ET isthmus widths (p=0.015 and p=0.014, respectively). The control group had significantly higher mastoid volumes compared to groups with cholesteatoma (p<0.001). Type 3 mastoid distribution was notably higher in groups with cholesteatoma (p<0.001). In the control group, the mean right and left ET angles were 25.13±3.35° and 24.67±3.38°, respectively. Conclusion: Tubotympanic angle and ET isthmus width may be a potential marker for cholesteatoma. Large-scale studies targeting the anatomy and function of the isthmus in combination with mastoid and ET radiomorphological data and clinical scores using standardized protocols may improve treatment strategies.

Anatomical factors of temporal bone residual cholesteatoma: our experience

The article describes clinical cases of invasive cholesteatoma of the temporal bone pyramid, leading to a massive destruction of the surrounding structures. Paying attention to the importance of knowing the microsurgical anatomy of critical structures of temporal bone (the anterior bony plate (cog), the tensor tympani fold and the tendon, the tympanic orifice of the eustachian tube, the pretympanic recess, tympanic sinuses) bearing a significance and helping to improve the removal of the invasive cholesteatoma.

Comparison of angle, length, and diameter of the eustachian tube of safe and unsafe CSOM based on CT scan in Dr. Zainoel Abidin General Hospital, Banda Aceh, Indonesia

Introduction: Damages in middle ear structures correlated with tubal dysfunction and impaired drainage; thus, it's associated with changes in angle, length, and tubal diameter. This study aimed to determine the ratio of angle, length, and diameter of Eustachian tube with safe and unsafe types of chronic suppurative otitis media (CSOM).Methods: Cross sectional analytical retrospective design, CT-Scan assessment for angle, length, the diameter of the tube on safe and unsafe type CSOM from January to December 2019 Angle is assessed using Reid's line, tube length by a tympanic orifice to pharyngeal orifice line, Tube diameter is measured from anteroposterior pre-tympanic line diameter. Results: From 61 CSOM patients, 70.5% safe type, 29.5% unsafe type. Safe type tube angle mean is 29.120, unsafe type 29.950, normal ear 28.230, thus no significant difference. A significant difference in the tube length (P = 0.001) is that the mean normal ear is 35.39 mm, smaller on safe type 33.58 mm, and unsafe type 29.53 mm. A significant difference in tubal diameter ratio (P = 0.001), normal diameter 2.19 mm, on safe type is 2.02 mm smaller, unsafe type 1.86 mm.Conclusion: The smaller length and diameter of the Eustachian tube will lead to unsafe type CSOM.

Anatomical Features Around Eustachian Tube in Eosinophilic Otitis Media With Eosinophilic Sinusitis.

This study investigated the relationships between anatomical findings around the eustachian tube (ET) and eosinophilic otitis media (EOM) accompanied by eosinophilic chronic rhinosinusitis (ECRS). This study employed axial, coronal, sagittal and oblique computed tomography. Patients who underwent endoscopic sinus surgery at the Department of Otolaryngology, Toho University Medical Center Omori Hospital and were diagnosed with ECRS (106 patients) based on the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis study were included. Subsequently, the presence of EOM accompanied by ECRS in 212 ear sides was assessed, and preoperative sinus computed tomography was used to evaluate various anatomical findings, such as the development of the sphenoid sinus and mastoid cells at the apex of petrous bone, the angle and length of the ET, and the size of the tympanic orifice of the ET. The relationships between these anatomical findings and the presence of EOM were analyzed statistically. EOM accompanied by ECRS was associated with a high peripheral blood eosinophil count and bronchial asthma. Among anatomical factors, the absence of peri-ET cells or petrous apex cells, and a low angle and short length of the ET, were risk factors for the onset of EOM. Anatomical factors such as the absence of peri-eustachian cells or petrous apex cells, and low angle or short length of the ET, are risk factors for the onset of EOM along with ECRS. Assessment of these factors may help in preventing the future onset or aggravation of EOM. 4 Laryngoscope, 131:E2689-E2695, 2021.

Morphologic measurements of 3D Eustachian tube model and their diagnostic value regarding Eustachian tube dysfunction – A cross-sectional observational study

PurposeTo investigate the diagnostic value of three-dimensional morphologic measurements of the Eustachian tube on computed tomography in Eustachian tube dysfunction. MethodThis prospective cross-sectional observational study includes forty patients with unilateral Eustachian tube dysfunction. The clinical diagnosis is verified using the Eustachian tube score – 7 and the Eustachian tube dysfunction questionnaire – 7. Computed tomography scans of the temporal bone are acquired while performing a Valsalva manoeuvre to improve the visualization of the air-filled Eustachian tube lumen. The Eustachian tubes are delineated on curved planar reconstructions, and three-dimensional models are constructed. Seven morphological parameters are measured for each Eustachian tube: the cross-sectional size of the tympanic and pharyngeal orifice; the visualization length; the inclination angles, and the curvature angles. Morphological measurements and Eustachian tube scores are correlated. ResultsThe mean value of the visualization length of the complete Eustachian tube and in its bony segment is significantly higher in healthy sides than in pathological sides (p = 0.034 and p = 0.029, respectively).There is a significant correlation between the Eustachian tube score - 7 and the cross-sectional size of the tympanic orifice (rP = 0.361; p = 0.022).The Eustachian tube score - 7 correlates significantly with the visualization length of complete Eustachian tube (rP = 0.436; p = 0.005) and its bony segment (rS = 0.598; p < 0.0001), respectively. ConclusionsThe cross-sectional size of the tympanic orifice may be a specific imaging feature indicating the obstructive Eustachian tube. However, 3D morphologic measurements of the Eustachian tube are insufficient to yield useful data about its function.

Eustachian Tube: Computed Tomography Analysis.

Eustachian tube has a major role in ventilation, drainage, and protection of the middle ear. High resolution computed tomography magnifies the role of preoperative imaging for detailed inner and middle ear anatomical information. The aim of this study was to find an applicable way by computed tomography imaging for assessment of Eustachian tube. The goal was to provide improved understanding of the Eustachian tube measurements and the relationship with middle ear in Egyptian population. Computed tomography measurements for Eustachian tube were done including; length of the bony and cartilaginous portions, Total length of Eustachian tube, as well as the width and height of the tympanic orifice of the Eustachian tube. Also, tubotympanic and Reid plane- Eustachian tube angles were measured. Within 200 studied ears in 100 subjects, the mean total Eustachian tube length was 40.19 ± 3.05 mm, mean length of the bony Eustachian tube was 11.69 ± 1.8 mm with significant longer Eustachian tube on left side, The mean length of the cartilaginous Eustachian tube was 28.5 ± 2.95 mm with significantly longer cartilaginous and total length in male (P < 0.0001). The mean width and height of the tympanic orifice of the Eustachian tube was 5.4 ± 0.79 and 4.85 ± 0.75 mm, respectively. The mean tubotympanic angle of the Eustachian tube was 148.11 ± 2.82°. The mean Reid plane- Eustachian tube angle was 27.69 ± 2.08° with significantly wider angle in males (P < 0.022). The Eustachian tube measurements can easily be obtained on computed tomography images, and are representative for the Eustachian tube anatomy. There is importance of extending computed tomography examinations beyond the middle ear cavity and the mastoids to the Eustachian tube in order to have more data on its condition and relations with different pathological conditions. Computed tomography provides improved understanding of the Eustachian tube measurements and relationship with middle ear structures.

A Structural Analysis of Tympanic Compartments of the Middle Ear in Patients With Down's Syndrome: A Temporal Bone Study.

Otitis media with effusion is a highly prevalent condition with DS. Knowledge of the volume of the tympanic compartments and the area of the tympanic isthmus might be important to find out the pathogenesis of highly prevalent otitis media with effusion in those patients. We compared the volume of the epitympanum, mesotympanum, and the areas of the tympanic isthmus and tympanic orifice of eustachian tube in temporal bones from patients with DS. We also investigated the eustachian tube histopathologically. The mean volume of the epitympanum and the mesotympanum was significantly smaller in the DS group than the control group. We found no significant difference in the mean diameter of the protympanic opening and tympanic orifice between the two groups. The mean narrowest area of the aerated and bony tympanic isthmus also was not significantly different between the two groups. An immature development of eustachian tube and cartilage was seen. We found mesenchyme remaining at the epitympanum and/or mesotympanum in all specimens in the DS group, and in five specimens in the control group. In the presence of the small middle ear, poorly developed eustachian tube, and tensor muscle, a vicious circle occurs, making otitis media with effusion difficult to resolve.

Влияние патологии протимпанума на результаты хирургического лечения пациентов с приобретенной холестеатомой среднего уха

The article analyzes the state of the protimpanum in various types of acquired cholesteatoma in adults and children. It was found that the spread of cholesteatoma in the protimpanum is observed for all types of acquired cholesteatoma, excluding the sinus cholesteatoma, and pathological changes in the mucous membrane of the protimanum and the bony part of the auditory tube in the form of polyps, granulations – only with primary acquired cholesteatoma. The influence of the pathology of the protimpanum on the choice of the type of surgical intervention and the method of rehabilitation of this middle ear section is noted. According to the study, the frequency of formation of residual cholesteatoma in the group of patients older than 15 years was 14,5%, including 0,9% in the protimpanum, and recurrent – 5,5%. In pediatric patients (from 3 to 15 years), residual cholesteatoma was detected in 18,7% of cases, including 1,9% in the protimpanum, and recurrent in 8,9%. A combination of risk factors such as the condition of the tympanic orifice of the auditory tube (its obstruction and / or anatomical constriction) and closed surgery technique predicted the development of recurrent cholesteatoma in both age groups. Pathological changes in the protimpanum did not affect the incidence of residual cholesteatoma. The key risk factors for the residual process were the type of cholesteatoma and the type of surgical intervention.

Predictors of recurrent pathology and prognosis of the results of surgical treatment of patients with acquired middle-ear cholesteatoma

A retrospective analysis of the results of surgical treatment of 436 patients (332 adults and 104 children under the age of 15 years) with acquired middle ear cholesteatoma was performed to identify possible predictors of relapse of the process and a prospective assessment of the results of surgical treatment. It was revealed that the leading factors in the development of residual pathology were: the presence of cholesteatoma in the area of destruction of the bone wall of the canal of the facial nerve, cholesteatoma of the hypothympanum, cholesteatoma in the place of destruction of the bone wall of the posterior cranial fossa. The key reasons for the formation of recurrent pathology were: children under 15 years of age, closed surgery, pathological changes in the tympanic orifice of the auditory tube and the presence of cholesteatoma in its lumen. Performing a closed operation in adults with pathology of the tympanic orifice of the auditory tube increases the risk of recurrent cholesteatoma by 18.6%, and in children by 20%. The choice of a closed method of surgical intervention for the epitympanic type of the disease can increase the risk of residual pathology by 17.2% in adults and 27.8% in children.

Assessment of the role of otoendoscopy in evaluating Eustachian tube and middle ear status during myringoplasty

ObjectiveTo assess the role of otoendoscopy in evaluating Eustachian tube and middle ear status during myringoplasty.BackgroundEustachian tube function has been the center of focus as a prognostic factor for middle ear surgery success because of its primary role in the middle ear aeration and in the pathogenesis of otitis media. Otoendoscopic evaluation of Eustachian tube allows visualization of the protympanic segment of the Eustachian tube and hidden recesses of the middle ear.Patients and methodsIn this prospective study, patients with a persistent dry central tympanic membrane perforation were operated at Otorhinolaryngology Department of Menoufia University Hospital in the period from March 2017 to February 2019. All patients were divided into two groups: group A included 50 cases that underwent otoendoscopic-assisted microscopic myringoplasty, and group B had 50 cases that underwent microscopic myringoplasty.ResultsThis study included 100 patients, with a mean age of 30.2 years. Overall, 42% of the patients were male and 58% of the patients were female. Otoendoscopic examination of middle ear in group A showed 20% of cases with adhesions and secretions at tympanic orifice of the Eustachian tube opening plus 8% of cases with congested mucosa at middle ear apparatus. The success of graft uptake was 94% in group A and 84% in group B.ConclusionThe result of this study supports the use of otoendoscopy in traditional microscopic myringoplasty. Endoscopy could be utilized efficiently to improve the visibility of the Eustachian tube opening and middle ear apparatus and then dealing with any pathology affecting them.

Establishment of a Large Animal Model for Eustachian Tube Functional Study in Miniature Pigs.

This study was performed to investigate whether miniature pigs are a suitable animal model for studies of the Eustachian tube (ET). Sixteen Chinese experimental miniature pigs were used in this investigation. Ten animals were used for anatomical and morphometric analyses to obtain qualitative and quantitative information regarding the ET. Three animals were used for histological analysis to determine the fine structure of ET cross-sections. Three animals were used to investigate the feasibility of balloon dilation of the Eustachian tube (BDET). The anatomical study indicated that the pharyngeal orifice and tympanic orifice of the miniature pig ET are located at the posterior end of the nasal lateral wall and anterior wall of the middle ear cavity, respectively. The cartilaginous tube was seen to pass through the whole length of the ET, the length of the cartilaginous part of the ET and the diameter of the isthmus were similar between humans and miniature pigs. The inclination of the ET in miniature pigs was larger than that in humans. The gross histology seemed to be slightly different between miniature pig and human, but the fine structures were essentially the same in both species. BDET experiments verified that the miniature pig model is suitable as a model for clinical operations. The miniature pig ET corresponds very well to that of humans. In addition, the miniature pig ET is suitable as a model for clinical operations. Therefore, the miniature pig is a valid animal model for ET study. Anat Rec, 302:1024-1038, 2019. © 2019 Wiley Periodicals, Inc.

Наш способ микроэндоскопического исследования слуховой трубы

help of fine optical systems. The authors suggested various techniques of micro-endoscopic examination of the auditory tube (Chays A., Magnan J.; Kimura et al.; Edelstein et al.; Klug C. et al.; Christopher J. Linstrom, etc.) However, it should be noted that all the previously presented techniques had a number of technical drawbacks, such as: low resolution of optical instruments; imperfection of the method of optical fibers feed the into the auditory tube; contamination of the distal endoscope part with mucous discharge; the absence of easy but reliable methods of controlling the optical fiber position in the middle ear. The article presents our method of micro-endoscopic examination of the auditory tube. Working at this task, we used a flexible unguided micro-endoscope Omex, model OME 400. The device has the following specifications: diameter: 0.78 mm, minimal bending radius: 25 mm, resolution: 15,000 pixels. The insertion of the instrument into the auditory tube was performed by means of a special device for examination and management of the auditory tube diseases and a special elastic catheter. The article provides various options of the auditory tube examination both from the pharyngeal orifice and from the tympanic orifice side during tympanoplasty. The group of authors conducted endoscopic examination of the auditory tube in 90 children aged 3 to 12 years during cold-plasma adenotomy and shunting of the tympanic cavities under general anesthesia. Besides, the examination of the auditory tube in adult patients during tympanoplasty was performed. The total number of examinations was 20 people, males and females, aged 29-61 years. We revealed a number of pathomorphological changes of the auditory tube mucous membrane in chronic secretory otitis media, chronic purulent otitis media. We observed edema, folding of the mucous membrane of the auditory tube in the membranous cartilaginous part; polypus-changed mucous membrane in the area of the auditory tube tympanic orifice; fibrin strands in the area of auditory ossicles and the absence of changes in the auditory tube in the middle ear pathology.

Age-related changes in the morphological relationship between the supratubal recess and the Eustachian tube

ObjectiveTo study age-related changes in the morphology of the supratubal recess (STR) and its relationship with the Eustachian tube (ET). MethodsSeventy randomly selected computed tomography (CT) images of non-pathological temporal bones of 49 patients were reviewed retrospectively. The patients were grouped according to age into 4 age groups: group A (0–3 years), group B (4–8 years), group C (9–18 years) and group D (19–50 years). Space analytic geometry was assessed to directly calculate the morphology of the STR and the ET. ResultsIn normal temporal bones, the STR was mostly presented with a solitary cell in life. The length of the STR was significantly longer in group C than that in group A (P<0.05). The width of the STR was declined with age and presented with significant difference among age groups (P<0.05). No significant difference was observed in the height of the STR in whole age groups (P>0.05). The aeration of the STR was intimately related with age-related morphological changes in the ET. But the important factors influencing the aeration of the STR were not always the same in different age stages. ConclusionThe extended length and declined width of the STR with age were mostly related with the prolonging bony part and inwardly bending cartilaginous part of the ET in children and adolescent aged from 0 to 18 years old. In adults aged more than 18 years old, the narrowed caliber of the tympanic orifice of the ET could induce the decline in the width of the STR with age, but unfolded horizontal cartilaginous part of the ET contributed to stable length and height in aeration of the STR.

Computed tomography findings of the bony portion of the Eustachian tube with or without patulous Eustachian tube patients.

To investigate the bony segment of the Eustachian tube (ET) using sitting 3D-computed tomography (CT) scans in Patulous Eustachian tube (PET) patients. A retrospective survey of medical records in Sen-En Hospital identified 43 patients and 43 ears with PET and 30 patients and 30 ears with sensorineural hearing loss or vertigo patients as the control. Diagnosis of PET was based on the Proposal on PET Diagnosis Criteria announced by the Otological Society of Japan in 2012. Patients were examined by cone beam CT (Accuitomo; Morita, Kyoto, Japan) in the sitting position. The heights and widths at the tympanic orifice, the middle portion, and isthmus were measured. The lumen of the bony portion was divided into three shapes: peritubal cells (PTC) poor type, PTC good with prominence type, and PTC good without prominence type. In PET patients and the control group, the PTC poor type was identified in nine (21%) and seven ears (23%), PTC good with prominence type was identified in 14 (33%) and seven ears (23%), and PTC good without prominence type was identified in 19 (45%) and 16 ears (53%), respectively. There was no significant difference between the two groups. At the tympanic orifice portion, the average height of the ET lumen was 5.99±1.29 and 6.04±1.41mm, and the average width of the ET lumen was 2.81±0.82 and 2.78±0.57mm in the PET and control groups, respectively. The PTC good with prominence type had a significantly smaller width in the tympanic orifice portion than the other types in each group (p<0.05). The width of the ET lumen in the tympanic orifice averaged 2.87±0.38 and 3.10±0.45mm in the PTC poor type, 2.23±0.70 and 2.22±0.48mm in the PTC good with prominence type, and 3.21±0.87 and 2.90±0.50mm in the PTC good without prominence type in the PET and control groups, respectively. The shape of the bony portion of the ET in PET patients is almost identical to that of controls. Thus, the bony portion has no influence on the pathology of patulous Eustachian tube syndrome. The PTC good with prominence type has a significantly smaller tympanic orifice portion width than the other types. Preoperative evaluation of the bony portion of the ET could provide useful information for ET surgeons.

Mouse model of experimental Eustachian tube occlusion: a surgical technique

Conclusion: The present study demonstrates a mouse model of chronic Eustachian tube (ET) dysfunction using a surgical technique that is reproducible and effective with low mortality and morbidity.Objective: To create a reproducible and effective mouse model of ET obstruction with a low operative morbidity.Methods: Forty healthy, male CBA/CaJ mice underwent the procedure. ET obstruction was performed on one side under general anesthesia; A small piece of dental material (Gutta Percha Points, Meta Biomed, Chungbuk, Korea) was placed via the tympanic orifice of the ET to occlude the entire ET. The contralateral ears of animals served as a control. One month after the operation, all ears were inspected under an operating microscope for signs of ET dysfunction. Primary outcome measures were the signs of ET dysfunction inspected through tympanic membrane (TM) 4 weeks after the operation and confirmation of ET occlusion by post-mortem dissection.Results: Forty (100%) of the treated mice ears developed ET dysfunction, as confirmed by the middle ear appearance on otoscopy and dissection post-mortem and 0% of the control ears at 4 weeks. The most common otoscopic signs were thickened TMs and middle ear effusions. No mortality or morbidity occurred either from anesthesia or surgery.

Osseous eustachian tube and peritubal cells in patients with unilateral cholesteatoma comparison between healthy and diseased sides using high-resolution cone-beam computed tomography.

We investigated the factors that may possibly cause primary acquired cholesteatoma. University-affiliated hospital. In 20 adult patients with unilateral cholesteatoma, the sizes of the osseous eustachian tubes (ETs) and the extent of peritubal and mastoid cell development in healthy and diseased ears were examined using high-resolution cone-beam computed tomography. The height and width of the ET were measured at the tympanic orifice, the isthmus, and the midpoint, as was the length of its axis. We also assessed the extent of development of peritubal and mastoid cells. There were no significant differences in the size of the osseous ET between the healthy and cholesteatoma sides, but significant correlations were found in height and width between the sides at the tympanic orifice and at the isthmus. In 80% of ears with cholesteatoma, the development of both peritubal and mastoid cells was poor and, in 5% more, one or the other was poor. Mastoid and peritubal cell development was good in 60% of healthy ears and poor in 20%. In the remaining 20%, only peritubal cell development was poor. There were no significant differences in the size of the osseous ET between the healthy and diseased sides of patients with unilateral cholesteatoma. Our results indicate that inhibition of air cell development in not only the mastoid region but also the peritubal region may contribute to cholesteatoma development.

연하에 동반된 클릭음을 주증상으로 하는 이관 개방증 환자에서 이관 고실측 개구부 폐쇄로 치유된 증례

연하에 동반된 클릭음을 주증상으로 하는 이관 개방증 환자에서 이관 고실측 개구부 폐쇄로 치유된 증례

Risk factors associated with severity of eosinophilic otitis media.

Eosinophilic otitis media (EOM) is an intractable otitis media associated with bronchial asthma. Clinical characteristics of EOM are apparent, but severe EOM, which is unresponsive to ongoing treatments, can occur. The present study aimed to investigate potential risk factors associated with the severity of EOM. We scored the EOM severity of 26 patients according to quantity of middle ear effusion (MEE), thickness of the middle ear mucosa, use of topical and oral corticosteroids, and use of antibiotics, all measured over a 3-month period. The scores for four 3-month periods (1 year) were averaged. We analyzed the prevalence of clinical variables by partial regression: sex, age, body mass index (BMI), duration of bronchial asthma, association of aspirin-intolerant asthma, Lund-Mackay score for sinusitis, mastoid pneumatization, width of the bony Eustachian tube at the tympanic orifice, percentage of eosinophils and immunoglobulin E in peripheral blood, and association of allergic rhinitis. Duration of bronchial asthma was defined as the period from onset of bronchial asthma to the age of first consultation at our hospital. Samples of MEE were taken for bacterial culture. The average severity score was 6.6 (out of 16). The severity score in the pathogen-positive MEE group was significantly higher than that in the pathogen-negative MEE group (p<0.05). The score was not significantly different between the seasons. Linear multiple regression analysis showed that BMI and the duration of bronchial asthma significantly affected the EOM severity score (p<0.05). The presence of aspirin intolerant asthma tended to be correlated with the severity score. The Lund-Mackay score tended to be negatively correlated with it. There is a significant association between the severity of EOM and obesity, as well as with the duration of bronchial asthma.

Temporal Bone Study of the Internal Carotid Artery at the Tympanic Orifice of Eustachian Tube

Temporal Bone Study of the Internal Carotid Artery at the Tympanic Orifice of Eustachian Tube

Three-Dimensional Image Analysis of the Temporal Bone in Patients with Unilateral Attic Cholesteatoma

We determined temporal bone anatomy in patients with unilateral attic cholesteatoma. We compared the affected and normal ears of ten patients with unilateral attic cholesteatoma using three-dimensionally reconstructed high-resolution computed tomography images of the temporal bone. We determined the eustachian tube angle, eustachian tube length, sizes of the tympanic orifice of the eustachian tube, the pars flaccida, and the mastoid cavity, and distances of the pars flaccida and the tympanic orifice of the eustachian tube from the epitympanic roof. No significant differences were found between the normal and affected ears with regard to the size of the eustachian tube orifice, eustachian tube length or distances of the pars flaccida and the tympanic orifice of the eustachian tube from the epitympanic roof. By contrast, the mastoid cavity and the eustachian tube angle were significantly larger in the normal ears than in the affected ears [mean, 6.99 cm(3) (S.D.,4.9 cm(3)) vs. 1.28 cm(3) (0.81 cm(3)) and 16.7° (4.12°) vs. 13.89° (5.30°), respectively]. The pars flaccida was significantly smaller in the normal ears [1.07 cm (0.31 cm)] than in the affected ears [2.19 cm (0.77 cm)]. The inherent anatomy of the eustachian tube may be particularly important in the formation of attic cholesteatomas.