Relationship between Clinical Test Results and Morphologic Severity Demonstrated by Sitting 3-D CT in Patients with Patulous Eustachian Tube

Objective: To investigate the correlation of sitting 3-D computed tomography (CT) scans of the Eustachian tube (ET) with subjective and objective findings in patients with patulous Eustachian tube (PET). Study Design: Retrospective. Setting: Tertiary referral center. Subjects: A retrospective survey of medical records in Sen-En Hospital identified 40 patients and 62 ears with PET between September 2014 and June 2015. Method: Diagnosis of PET was based on the presence of three characteristic aural symptoms (autophony of voice or breathing sounds, and aural fullness), as well as verification of synchronous movement of the tympanic membrane in response to forced breathing under an endoscope. Any pressure changes in the external auditory canal (EAC) elicited by deep breathing and sniffing were detected by tubotympanoaerodynamography (TTAG). In addition, sonotubometry was performed where two parameters were used determined to evaluate ET function. Patients were examined by 3-D CT (Accuitomo; Morita, Kyoto, Japan) in the sitting position. The length of the closed ET lumen section was measured. Ears were divided into three groups as follows: completely open, closed-short (3 mm or less), and closed-long (longer than 3 mm). Results: The median length of the closed section of the ET lumen was 1.85 ± 2.69 mm in positive findings of PET. The three groups were significantly different in both aural fullness (p = 0.023) and, similarly, the difference in tympanic membrane movement (p = 0.032) among these three groups was also significantly different (p = 0.032). However, for autophony of breathing sounds, there was no significant difference with regard to autophony of breathing sounds among these three groups (p = 0.324). Although TTAG findings were did not reveal any significantly difference among these three groups (p = 0.589), the difference was significant (p = 0.001) in degree of EAC pressure change in TTAG. The difference among the three groups was significant (p = 0.001) based on sonotubometry findings. Conclusion: Under resting conditions, the lengths of the closed area of the ETs in PET groups are clearly shorter than in groups without PET based on sitting position CT scans in resting condition. Among the symptoms and clinical test findings including the ET function test results, the presence of tympanic membrane movement induced by respiration, the high degree of EAC pressure change in TTAG, as well as the positive results of sonotubometry are significantly correlated with the positive findings of sitting CT revealing the open ET.