Experimental Comparative Study On The Accuracy Of Multiplanar Composite Deformity Correction Using Different Measuring Methods For Mounting Parameters Of Taylor Spatial Frame (TSF)

Objective: To compare the influence of three different measurement methods of mounting parameters for Taylor Spatial Frame(TSF)on the accuracy of deformity correction,by simulating surgical correction of the multiplanar complex deformity made by Sawbone artificial bone model.The advantages and disadvantages of these three methods were discussed to provide reference for clinical application.Method:(1)12 Sawbone artificial bone models from the same manufacturer were selected and their quality was checked,and then the multiplanar complex deformity models were made.Firstly,the planned osteotomy position was marked on the model,and the deformity model was fixed with TSF.Three frame parameters of each TSF,namely the diameter of the proximal distal ring and the length of the 6 structs were recorded,and then each model was truncated at different parts to make multiplanar complex deformity.The 6 deformity parameters were determined from the preoperative biplanar radiographs of the entire tibia.They represent the 6 possible axes of deformity in coronal plane angulation,sagittal plane angulation,axial rotation,coronal plane translation,sagittal plane translation,and axial translation deformity.The mounting parameters of the TSF were measured by intraoperative c-arm fluoroscopy,postoperative full-length anterioposterior and lateral X-ray and postoperative three-dimensional computed tomography.The mounting parameters measured by the three methods were input into the online software of Taylor Spatial Frame,in which a day by day prescription was generated,and 6 structs were adjusted according to the prescription for deformity correction.After the completion of the adjusting,the full-length anterioposterior and lateral X-ray was taken again to calculate the residual deformity.The measured values of mounting parameters of the three methods and the residual deformity after the deformity correction were analyzed and compared by statistical methods.Record the time spend by the operator in the measurement of the mounting parameters.(2)In this study,three typical clinical cases were selected to measure the mounting parameters according to these three methods,in order to show their clinical application.Bone Ninja software was used for measurement and preoperative planning,and the Taylor Spatial Frame was fixed and minimally invasive osteotomy was performed during the operation.Relevant parameters were input into the online software to obtain the initial prescription.After finishing the adjustment of the structs,anterioposterior and lateral radiographs of the entire tibia were taken again to calculate the residual deformity,and further electronic prescription was generated by TSF online software until the results of the deformity correction were satisfactory.Result: There was no significant difference among the three groups measured by the three mounting parameters measurement methods(P>0.05)?Mounting parameters were measured by intraoperative C-arm fluoroscopy,postoperative three-dimensional CT and postoperative full-length X-ray,and the parameters were inputted into software to correct deformities.The mean values of residual coronal angulation(valgus and valgus)were 0.83,0.67 and 0.33 degrees respectively,while the mean values of residual coronal displacement(medial and lateral displacement)were 0.33 mm,0.50 mm and-1.17 mm respectively,and the residual sagittal angulation(anteroposterior and posterior angulation)was 0.50,0.50 and 1.67 degrees respectively,and the residual sagittal displacement(anterior and posterior displacement)were-1.67 mm,-2.17 mm and-0.50 mm,respectively.The mean values of residual coronal angulation,sagittal angulation and coronal plane displacement were the smallest in three-dimensional CT measurement,while those of residual sagittal plane displacement were the smallest in the method of C-arm fluoroscopy.The mean values of residual sagittal,sagittal and coronal plane displacements were the largest in the full-length anterioposterior and lateral X-ray measurements,while those of residual coronal plane angulation were the largest in the method of C-arm fluoroscopy.Nevertheless,there was no significant difference in residual deformities after deformity correction using the measured values of the three methods.(P > 0.05).Conclusion:There was no difference between the three sets of values measured by the three TSF mounting parameters measurement methods: intraoperative C-arm fluoroscopy,postoperative full-length anterioposterior and lateral X-ray measurement,and postoperative three-dimensional CT measurement.In the deformity correction of the first prescription of the multiplanar composite deformity,the accuracy of deformity correction using the three TSF mounting parameters measurement methods is not different.These three methods can accurately define the mounting parameters of the Taylor Spatial Frame and accurately correct the multiplanar composite deformity.All three methods can be selected in clinical application.If fracture reduction or TSF-assisted immediate deformity correction are needed during operation,intraoperative C-arm fluoroscopy can be used at this time.However,this method needs more time to measure parameters during operation,which will prolong the operation time.Postoperative three-dimensional CT measurement is the most time-saving method for the operator.It only needs to read the report of the radiology department,but it may increase the radiation dose for the patient.Postoperative full-length X-ray measurement method requires relatively high requirements,which requires patient posture coordination in order to measure more accurate parameters.