[CT features of abnormally whole-course wide eustachian tubes with microtia and atresia]

Objective: To study the clinical and CT features of the abnormal whole-course wide of eustachian tube (AWWET) with microtia and atresia(MA). Methods: The clinical and CT data of 19 patients (20 ears) from January 2017 to December 2021 with AWWET with MA were retrospectively analyzed, including 15 males and 4 females. The age ranged from 5 to 16 years, with an average of 9.5 years. 50 patients with common MA without wide eustachian tube(ET) as a case control group, including 32 males and 18 females.The age ranged from 5 to 16 years, with an average of 9.2 years. 20 patients (40 ears) who had normal ear CT for tinnitus, otalgia as a normal control group, including 12 males and 8 females. The age ranged from 5 to 16 years, with an average of 12.5 years. We measured the dimension and length of the bony portion of the ET, the total length, the angle between the bony portion and the cartilage portion, and the horizontal angle of ET on CT imagings, and compared with 40 normal ears by SPSS 27.0 software. Results: According to the relationship between AWWET and tympanum, patients were divided into the communicated group and the blocked group. A male predominance, left ear predominance, with high incidence of hemifacial microsomia exhibited in both groups. AWWET was presented as a widened lumen on CT. In 11 ears (4 ears in the communicated group, 7 ears in the blocked group), ETs bifurcated, the upper bony tube extended to the sphenoid body, the lower part continued down to cartilaginous ET and opened onto the nasopharynx, with"mastoid-like"pneumatization of the sphenoid body in 6 ears. The middle ear deformity in case group was more serious than MA control group, especially the blocked group. The incidence of otitis media in the communicated group was lower than that in the MA control group, and 4 cases in the blocked group had effusion in the ET. Compaired with normal ear, the bony ET elongated significantly in the AWWET groups, and the whole course of ET was significantly shortened, specially in the blocked group. The angle between the bony ET and the cartilaginous ET was decreased and the horizontal angle of the ET increased in the AWWET groups, the difference was considered to indicate statistical significance(P<0.05). Conclusions: AWWET with MA is rare, a male predominance, left ear predominance, and with high incidence of hemifacial microsomia. The middle ear deformity is more serious than common MA, especially in the blocked group. The incidence of otitis media in the communicated group is significantly lower than that in the common MA, and the blocked group may be accompanied by ET inflammation.