[Isolated congenital middle ear malformations: comparison of preoperative HRCT and surgical findings].

To compare preoperative temporal bone HRCT readings to intraoperative findings during exploratory tympanotomy for suspected cases of isolated congenital middle ear malformations（CMEMs） and summarize the malformations that can be diagnosed with HRCT. A retrospective study was conducted. All cases were confirmed as isolated CMEMs during surgery. Detailed clinical records were reviewed, with a focus on imaging and surgical findings. One hundred and fifty-two patients and 168 ears were reviewed. One hundred and seven cases（63.7%） could be identified as isolated CMEMs and at least one as middle ear anomaly using preoperative HRCT. Sixty-one cases（36.3%） were reported to be completely normal and the patients underwent exploratory tympanotomy to determine the final diagnosis. Stapes fixation, either alone or associated with other ossicular chain anomalies, contributed to 51.2% of the cases.The stapes and incudostapedial complex are the most commonly involved structures. HRCT provides helpful preoperative clinical information in CMEM.Most cases of aplasia or dysplasia of the ossicular chain, e.g., aplasia/dysplasia of the long process of the incus, aplasia of the stapes'superstructure, and atresia of the oval window were easily identified in preoperative HRCT. However, fixation of the ossicular chain can be elusive in HRCT, and exploratory tympanotomy is needed for a definitive diagnosis.