Xiangxue Kong1, Lei Tang1, Qiang Ye2, Wenhua Huang1, Jianyi Li3,4. 1. Department of Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong, China. 2. Department of Radiology, The Third Affiliated Hospital, Southern Medical University, Guangzhou, China. 3. Department of Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong, China. lijianyi@outlook.com. 4. Department of Orthopedics, Nanhai Hospital, Southern Medical University, Foshan, China. lijianyi@outlook.com.
Abstract
PURPOSE: Accurate and safe posterior thoracic pedicle insertion (PTPI) remains a challenge. Patient-specific drill templates (PDTs) created by rapid prototyping (RP) can assist in posterior thoracic pedicle insertion, but pose biocompatibility risks. The aims of this study were to develop alternative PDTs with computer numerical control (CNC) and assess their feasibility and accuracy in assisting PTPI. METHODS: Preoperative CT images of 31 cadaveric thoracic vertebras were obtained and then the optimal pedicle screw trajectories were planned. The PDTs with optimal screw trajectories were randomly assigned to be designed and manufactured by CNC or RP in each vertebra. With the guide of the CNC- or RP-manufactured PDTs, the appropriate screws were inserted into the pedicles. Postoperative CT scans were performed to analyze any deviations at entry point and midpoint of the pedicles. RESULTS: The CNC group was found to be significant manufacture-time-shortening, and cost-decreasing, when compared with the RP group (P < 0.01). The PDTs fitted the vertebral laminates well while all screws were being inserted into the pedicles. There were no significant differences in absolute deviations at entry point and midpoint of the pedicle on either axial or sagittal planes (P > 0.05). The screw positions were grade 0 in 90.3% and grade 1 in 9.7% of the cases in the CNC group and grade 0 in 93.5% and grade 1 in 6.5% of the cases in the RP group (P = 0.641). CONCLUSION: CNC-manufactured PDTs are viable for assisting in PTPI with good feasibility and accuracy.
RCT Entities:
PURPOSE: Accurate and safe posterior thoracic pedicle insertion (PTPI) remains a challenge. Patient-specific drill templates (PDTs) created by rapid prototyping (RP) can assist in posterior thoracic pedicle insertion, but pose biocompatibility risks. The aims of this study were to develop alternative PDTs with computer numerical control (CNC) and assess their feasibility and accuracy in assisting PTPI. METHODS: Preoperative CT images of 31 cadaveric thoracic vertebras were obtained and then the optimal pedicle screw trajectories were planned. The PDTs with optimal screw trajectories were randomly assigned to be designed and manufactured by CNC or RP in each vertebra. With the guide of the CNC- or RP-manufactured PDTs, the appropriate screws were inserted into the pedicles. Postoperative CT scans were performed to analyze any deviations at entry point and midpoint of the pedicles. RESULTS: The CNC group was found to be significant manufacture-time-shortening, and cost-decreasing, when compared with the RP group (P < 0.01). The PDTs fitted the vertebral laminates well while all screws were being inserted into the pedicles. There were no significant differences in absolute deviations at entry point and midpoint of the pedicle on either axial or sagittal planes (P > 0.05). The screw positions were grade 0 in 90.3% and grade 1 in 9.7% of the cases in the CNC group and grade 0 in 93.5% and grade 1 in 6.5% of the cases in the RP group (P = 0.641). CONCLUSION: CNC-manufactured PDTs are viable for assisting in PTPI with good feasibility and accuracy.
Authors: Sheng Lu; Yuan Z Zhang; Zheng Wang; Ji H Shi; Yu B Chen; Xing M Xu; Yong Q Xu Journal: Med Biol Eng Comput Date: 2012-03-31 Impact factor: 2.602