| Objective To investigate the value of CBCT on Cochlear implant electrodes assessment after cochlear implantation;To study the relationship between ECAP and depth of implantation electrodes,and distance between the electrode modiolar.Methods Collecting 50 patients who were severe sensory neural hearing loss,that planted artificial cochlea in Ningbo NO.2 Hospital from the July 2015 to February 2017.18 patients were implanted COCHLEAR Nucleus CI512 fifth generation artificial cochlea,and 32 patients were implanted NUROTRON CS-10A artificial cochlea.When CI were stared up,high resolution CBCT scan and 64 slice CT scanning were performed to evaluate the position of the electrode,the number of electrodes,the depth of electrode implantation and the distance between electrode and modiolar,to investigate the value of CBCT on Cochlear implant electrodes assessment.30 patients of CS-10A cochlear implant,measure the depth of electrode imbedded in cochlea,the distance between electrode and modiolar,ECAP threshold after the electrode in cochlea was three-dimensional contour reconstituted by CBCT,then analyze the correlation among them.Results ①.MDCT count clearly 231 electrodes of 18 cases with Nucleus CI512,an average of(12.8+1.5)electrodes,CBCT can clearly count 335 electrodes,an average of(18.6+1.5)electrodes;MDCT count clearly 186 electrodes of 32 cases with NUROTRON CS-10A,an average of(5.8+1.7)electrodes;CBCT count clearly 504 electrodes,an average of(15.7+1.9)electrodes.High resolution CBCT and MDCT show significantly statistical differences in the implanted electrode clear count and different cochlear electrode count(P<0.01).The number of the 22 electrodes of implanted cochlear was more than that of the 24 electrodes,and the difference between the two groups was statistically significant(P<0.05).CBCT shows the postoperative electrodes in the scala tympani in 42 cases,and in the vestibular order in 2 cases,failed to determine in 6 cases.MDCT shows the postoperative electrodes in the scala tympani in 43 cases,in the vestibular order in 2 cases,5 cases failed to determine,two types of examination on location estimation results are consistent.②.The average depth(19.79±2.36)mm of 30 cases with CS-10A electrode was measured by the direct method of MDCT,and the average depth(19.61 ±2.34)mm of 30 cases of electrodes was measured by the direct method of CBCT,and the average depth(19.33±2.20)mm was measured by indirect method.③.CBCT measured in 30 cases the vertical distance between modiolus and NO.1,NO.10,NO.20 electrode surface are(0.36+0.1)mm,(0.45±0.2)mm,(0.53+0.2)mm respectively.The electrode is more deep,more close to cupula cochleae,The closer the distance from the average distance of the modiolus.④.Operating of NUROTRON CS-10A of 30cases,the average ECAP threshold values of NO.1,NO.10,NO.20 electrodes were(0.36±0.1)mm、(0.45±0.2)mm、(0.53±0.2)mm respectively.Single factor correlation analysis shows negative correlation with the average threshold of ECAP and depth of implanted electrodes(R=0.583,P<0.05),threshold of ECAP of the corresponding electrode and the distance between modiolus and electrode shows a significant positive correlation(R=0.732,P<0.05.)Conclusion ①.Compared with 3-D reconstruction of multi-detector CT,high resolution CBCT can not only display the electrode position in the cochlea,but also clearly measure the length and number of electrodes.The imaging evaluation of the cochlear electrode can be performed in the clinic instead of Multi-detector CT.②.CBCT can be used to measure the depth of electrode implantation and the distance between electrode and modiolar,which can be used to provide accurate and specific image data for the evaluation of clinical curative effect.③.The distance between electrode and modiolar is positive with threshold of ECAP,the distance is more closer,the threshold of ECAP is more lower;the depth of electrode implanted is negative with the average threshold of ECAP,the depth is more longer,the threshold of ECAP is more lower. |
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