| Objective:To investigate the correlation among the mastoid air cell volume, external and middle ear Jahrsdoerfer score and the degree of ossicular malformation to improving the understanding of malformation of external and middle ear. To study the application value of spiral CT and the subsequent processing technique in perioperative evaluation of middle ear malformation.Methods:(1) patients:Patients in the first affiliated hospital of Jinan university were collected and divided into three groups. The first group was aiming to investigate the correlation among the mastoid air cell volume, external and middle ear Jahrsdoerfer score and the degree of ossicular malformation.39 ears in 33 patients (older than 6 y) with congenital external and middle ear malformations were selected; the second group was aiming to make a control study by comparing data of images and surgery.27 ears in 25 patients with congenital external and middle ear malformations were selected; the third group was aiming to analyze images of middle ear malformations after operation. CT images of 10 ears in 9 congenital external and middle ear malformation patients were collected.(2) Data processing and image analysis:Bilateral mastoid axial CT scan and intensive zoom reconstruction were performed, later multi-plane restructuring and simulation endoscopy volume ossicular restructuring imaging were procedured. Make reconstruction of the unilateral mastoid region using 3D minimum intensity projection workstation. Only tympanic and gas in mastoid were remained using three-dimensional cutting technology. Mastoid air cell volume were measured by software.CT images were observed and recorded by 2 experienced imaging diagnostic physicians. Analyzing contents includes:external auditory canal, malleus, incus, stapes, hammer stirrup joint, anvil stirrup joint, round window, oval window and the location and morphous of eustachian tube. Consensus opinion by making common discussion would be accepted if conclusions were inconsistent.Considering relevant literature and clinical data, instituted the denom of Jahrsdoerfer score for external and middle ear malformation and the denom of degree of ossicular chain abnormality score. Count all the score collected in the study.(3) Statistical analysis:Linear correlation analysis was made among the volume of the mastoid air cell, external and middle ear ossicular malformations and the Jahrsdoerfer score using statistical software of SPSS 13.0. All data were divided into 2 groups by Jahrsdoerfer score 5, t test were made between the two groups; ROC analysis were made between the mastoid air volume and external/middle ear Jahrsdoerfer score;α=0.05, there was significant difference when P< 0.05. At last, consistency checking were made between the CT scan images and results in the surgery.Results:Group I:statistical analyzing of 39 ears(older than 6 y) with Congenital external/ middle ear malformations:①there was correlation between any two aspects of mastoid air cell volume, external and middle ear Jahrsdoerfer score and the degree of ossicular malformation.②it was reported that surgery was not advised when Jahrsdoerfer score was less than 5. There was significant difference between groups divided by Jahrsdoerfer score of 5.③patients could be treated by surgery when Jahrsdoerfer score was more than 5. ROC analyzing results:Cut-off point of 0.89 cm3 could be one of feasible index for surgery.Group II:27 ears had taken surgery in this group:CT images were confirmed to surgery in the circumstances of deformity and absence in the external auditory canal, hammer anvil joint and anvil stirrup joint.24 hammer abnormity or absence ears were detected by surgery, while 23 of them were detected by CT.23 anvil abnormity or absence ears were detected by surgery, while 20 of them were detected by CT.20 stirrup abnormity or absence ears were detected by surgery, while 18 of them were detected by CT.9 bony closure of fenestra nov-ovalis ears were detected by surgery, and 8 of them were detected by CT.2 ears without auditory tube were detected in surgery which was coincidence to CT. Abnormal neural tube in 14 ears were detected by surgery, while 1 of them was normal on CT image. Diagnostic accuracy of CT in abnormalities of various parts was more than 90%. The coincidence of CT and surgery in diagnosing affections in chain of ossicles was high. Kappa value of each structure was more than 0.75.Group III:CT examination revealed the location and reconstruction of ossicular chain were good in the 9 ears of hearing improved consciously or by hearing test in the 11 middle ear deformity; there were 2 ears with hearing breakdown after surgery, CT scan showed one of them have separation of the reconstruction ossicular chain and the fenestra nov-ovalis, with the other one have displace of the stirrup and the fenestra nov-ovalis.Conclusions:1,There was correlation between any two aspects of mastoid air cell volume, external and middle ear Jahrsdoerfer score and the degree of ossicular malformation. Mastoid air cell volume and Mastoid air cell can be one of feasible index for surgery in the external/middle ear deformity.2,There is high accurate of CT in diagnosing the external/middle ear malformations which can provide effective guidance in making clinical procedure and path of surgery and decreasing complications.3,CT scan can comprehend the reconstruction location and conjunction situation of ossicular chain, which may provide reliable observation index after surgery. |
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