Clinical application and effect of individual 3D printing model on pedicle screw placement for upper cervical spine fracture / 中华创伤杂志

ABSTRACT

Objective To investigate the accuracy and feasibility of individual 3D printing model for pedicle screw placement in treating patients with upper cervical spine fracture.Methods A retrospective case control study was conducted to analyze the clinical data of 30 patients with upper cervical spine fracture admitted to Ningbo No.6 Hospital from August 2013 to December 2018.There were 19 males and 11 females,aged 45-67 years with an average age of 53.5 years.The 15 patients in the study group were treated with pedicle screw fixation and another 15 patients in the control group were treated with traditional freehand screw fixation.A total of 120 pedicle screws were implanted,with 60 screws in each group.The operation time,intraoperative blood loss,preoperative and postoperative visual analogue score (VAS),Japan Orthopedic Association (JOA) score were recorded.The position and grade of screws were evaluated according to Kawaguchi's evaluation method of screw grade after operation.The patients took monthly reexamination for the first three months after discharge.In the first two months after discharge,the patients took X-ray examination for observation of screw loosening or rupture of internal fixation.At the third month after operation,the patients took CT of cervical spine for observation of bone healing and fusion.Results The mean follow-up duration was 17.8 months (range,13-21 months).The study group had shorter operation time (99.13 ± 3.04)minutes compared with the control group (107.00 ± 6.92) minutes (P ＜ 0.01).There were no significant differences in intraoperative blood loss,preoperative VAS,JOA scores before operation and 1 year after operation between the two groups (P ＞ 0.05),but the VAS in study group was significantly lower than that in control group (P ＜ 0.05).In the study group,the VAS score 1 year after operation [(2.3 ± 0.5) points] was lower than that before the operation [(7.7 ± 0.7) points],and the JOA score [(16.8 ± 0.4) points] was significantly higher than that before the operation [(15.9 ± 0.7) points] (P ＜ 0.01).In the control group,the VAS 1 year after operation [(2.5 ± 0.5) points] was significantly lower than that before operation [(7.5 ±0.5)points] (P ＜0.01),and the JOA score [(16.5 ±0.5)points] was significantly higher than that before operation [(15.9 ± 0.8)points] (P ＜ 0.05).In the study group,according to the CT results,there were 28 atlas pedicle screws of grade 0 (93.3％),two of grade 1 (6.7％),0 of grade 2,0 of grade 3,and there were 27 axial pedicle screws of grade 0 (90.0％),three of grade 1 (10.0％),0 of grade 2,and 0 of grade 3.In the control group,there were 25 atlas pedicle screws of grade 0 (83.3％),four of grade 1 (13.3％),one of grade 2 (3.4％),0 of grade 3,and there were 27 axial pedical screws of grade 0 (90.0％),three of grade 1 (10.0％),0 of grade 2,and 0 of grade 3.There was no significant difference in the accuracy of pedicle screw placement between the two groups (P ＞ 0.05).No serious complications such as spinal cord or vertebral artery injury occurred.At 3 months after operation,CT showed that the fracture of cervical vertebra healed.Conclusion Individualized 3D printed cervical spine model can guide the pedicle screw placement for upper cervical spine fracture,which can shorten the operation time,reduce the postoperative pain of patients,improve the accuracy of screw placement,and reduce the risks related to operation.