| Objective: To discuss the preoperative value of high resolution computered tomography(HRCT)axial imagings of temporal bone and pure tone audiometry in evaluating the condition of ossicular chain in patients with the middle ear cholesteatoma.Methods:HRCT axial imagings of temporal bone and pure tone audiometry data were retrospectively conducted on 130 cases(132ears)with acquired middle ear cholesteatoma.1.Depending on the degree of audiovisual bone damage,a grading strategy was established to divide each auditory ossicle into grades 1 to 3,and then CT grading was compared with intraoperative grading to calculate the accuracy of CT diagnosis.2.The ossicular chain was divided into the complete ossicular chain group and the interrupted ossicular chain group,depending on the intraoperative situation.The effects of the two groups on hearing were compared.3.On the basis of the intraoperative grading and the flexibility of ossicular chain,the ossicular chain was scored to study the influence of the degree of ossicular chain lesions on hearing.Results:1.The overall accuracy of axial CT of temporal bone in the diagnosis of auditory bone injury: malleus 85.6%,incus 80.3%,stapes 81.8%.2.In the group of interrupted,the differences of average air-conduction threshold,average bone-conduction threshold and average air-bone gap(ABG)were significantly higher than those of the complete group(P<0.01).3.With the increase of ossicular chain score,the average air-conduction threshold,average bone-conduction threshold and average ABG also increased.Conclution:1.The axial CT of the temporal bone showed a high accuracy in preoperative diagnosis of malleus and stapes.Although it was affected by soft tissue density shadow,the temporal bone axial CT was of great significance in preoperative evaluation of the status of auditory ossicles.2.The more serious of the ossicular chain,the poor the hearing.3.The worse the flexibility of the ossicular chain,the worse the hearing. |
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