| OBJECTIVES: To evaluate precision of pedicle screw placement with assistance of Ti Robot Orthopedic Robotic System in cervical,thoracic and lumbar vertebra and explore the intraoperative influencing factors of pedicle screw accuracy.To compare advantages and disadvantages between robotic spinal surgery,percutaneous minimally invasive surgery and traditional open and free-hand operation.To investigate the future direction of domestic orthopedic robot system and influence of robotic surgery on the development of minimally invasive spinal surgery.METHODS: 49 patients over the age of 18 with clear surgical indications,complete preoperative radiographic examination and without contraindication were continuously selected to undergo posterior cervical surgery,posterior thoracic surgery and multi-segment posterior lumbar surgery.The pedicle width and facet angle were measured by preoperative computed tomography(CT)images,and the position of optical navigation spinous process clamp relative to the operative area was recorded during the operation.The accuracy of pedicle screw was evaluated by Gertzbein method through postoperative CT,and factors affecting the accuracy of pedicle screw placement were analyzed by Kruskal-Wallis test and Chi-square test.A retrospective case control study was performed including 52 cases of thoracolumbar fractures without neurological symptoms admitted to our hospital from February 2018 to June 2019 and treated with robot-assisted percutaneous reduction and internal fixation surgery(RA group),fluoroscopy-guided percutaneous reduction and internal fixation surgery(FG group)and posterior open reduction and internal fixation surgery(OP group).Compared operating time,fluoroscopy time(FT),radiation exposure,blood loss,accuracy of pedicle screw placement,bed rest time,length of stay(LOS),relative anterior height of injured vertebra and injured vertebra Cobb’s angle at preoperative and 6 months after operation,Visual analogue scale(VAS)and Japanese Orthopedic Association(JOA)scores before the operation,on the third day and 6 months after operation between three groups.One-way ANOVA and Bonferroni method were used for measurement data,and Z test and CMH-2 test were used for enumeration data to analyze the differences of three different groups.RESULTS: In 49 patients,377 pedicle screws were implanted with robot-assistance,with an average accuracy of 97.08%,100% in cervical,92.23% in thoracic and 97.56% in lumbar.Lumbar screw placement was more accurate than that of thoracic vertebra(P(27)0.05),and the accuracy of pedicle screw placement was related to the ratio of pedicle width to screw diameter(P(27)0.001),but not to the lumbar facet angle and the position distance between the optical tracer and the operated vertebra(P(29)0.05).In the 52 cases of thoraco-lumbar fracture,the operation time,blood loss,bed rest time and LOS of the RA group and the FG group were all less than those of the OP group,and the screw placement accuracy of the RA group was higher than that of the FG group and the OP group,the differences was statistically significant(P(27)0.05).Compared the radiation exposure and FT,FG group had the most and RA group the least(P(27)0.05).There was no significant difference in the relative anterior height of injured vertebra and Cobb’s angle among three groups pre-and post-operatively(P(29)0.05).The VAS scores and JOA scores of RA group and FG group were better than that of OP group at post-op third day(P(27)0.05)and there is no statistically significant difference in long time follow-up.CONCLUSIONS: The main risk factor of pedicle screw accuracy placement is the width of pedicle.The accuracy of screw placement with robot-assistance is high and the multi-segment works well for a long time.It also has the advantages of shorter operation time,less trauma,faster recovery and less radiation exposure.Robot surgery is going to be a good choice for minimally invasive spinal surgery. |
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