3D-Printing Model-Assisted Posterior Internal Fixation For The Treatment Of Atlantoaxial Instability

BackgroundAtlantoaxial instability is caused by the factors such as infection,trauma,developmental malformation,it serious influence the patient’s quality of life,mild symptom cause pillow neck pain,serious symptoms can cause spinal cord compression symptoms even death,posterior Internal fixation technique of atlanto-axial has widely used in treatment of atlantoaxial instability because of its strong visibility and higher rate of bone graft fusion,and it site of nailing is often axis pedicle.Due to the complexity of atlanto-axial vertebral anatomy,and adjacent to important vascular nerves,and the vertebral body structure and bone structure of every patients are different,it creates a great difficulty for surgery.There is no more safe and reliable nailing data in common as reference so far(nailing position,depth,direction,etc).So it need individualized customization and individualized treatment.ObjectiveFor some patients with atlanto-axial vertebral instability,using digital technology and 3D printing technology to simulate the process of nailing at preoperative to get personalized data nailing.And then to explore the effect of the operation model of 3d printing,operation time and other factors.Methods1 From March 2013 to March 2015,a total of 30 patients with atlantoaxial instability according to incorporated into and exclusion criteria,summary of 30 patients with atlanto-axial vertebral instability were randomly divided into two groups: the research group and the control group respectively,all cases accept thin CT layer scanning at preoperative,and then using 3D reconstruction,at the same time accept CT angiography and reconstruction of vertebral artery,all patients required CTA images and atlanto-axial vertebral anteroposterior and lateral film,15 cases of control group of make CTA data disc to DiCOM data storaged.2 Input the DiCom data of research group to Geomagic software to make the image data reverse reconstruction,and then input the 3D images that initial to MIMIC software to repair the integration,finally produces stl.format file.This file after post-processing can be imported into desktop 3d printer(MakerBot Replicator 2)to print layer-by-layer,Finally acquire 1:1 cervical vertebral body simulation model,simulate nailing on the model at preoperative to obtain individualized nailing data and choose the best screw length,diameter and choose the best points and angles for setting screw,Make the model disinfection by epoxy ethane and then bring it to the operating theatre.Compared to lesion area real-time at intraoperative as reference in the operation.3 Two groups of patients are all performed atlanto-axial vertebral posterior internal fixation surgery and use neck collar fixed head after operation.Reviewing cervical X-ray to know the condition of internal fixation on the 2nd day after operation and review cervical CT to know the condition of1 internal fixation and bone graft fusion.If there is compression of the spinal cord,plus do MRI.Clinical function evaluation using VAS score and JOA score to evaluate the effect of posterior internal fixation of patients of two groups.By measuring the numerical value of ADI and CMA to evaluate the effect of reduction of patients of two groups,and statistical comparison analysis such factors as situation of internal fixation、the situation of breathing improvement、average length of hospital stay、average operation time of patients of two groups.Results1 The blood loss,operative time in research group was significantly lower than the control group,the difference was statistically significant(P>0.05).And the hospitalization days less than the control group,but no statistically significant difference(P<0.05).2 Postoperative MRI and CT scanning show that ADl was significanfly reduced.CMA was significantly increased,medullary ventral compression obviously alleviated or disappeared and there was a significant statistical difference(P<0.05).3 The VAS scores of two groups of patients postoperative were significantly lower than the preoperative and the JOA scores are higher than that of preoperative.The patients in research group postoperative JOA score is significantly higher than the control group and the VAS score was significantly lower than the control group,the difference was statistically significant(P < 0.05)4 The nailing process of the two groups of patients is smooth,postoperative follow-up is no fracture and loose,evaluate the result according to the XU nailing standard:The nailing effect of research group is significantly better than that of control group,the difference was statistically significant(P < 0.05).Conclusions1 Posterior internal fixation operation can make the neurological symptoms and motor function of patients improved significantly.2 Through 3D navigation technology for nailing channel simulation can effectively help the performer,especially provide intuitive directivity help for beginners to know the nailing depth,the angle and choose the most suitable nail.3 According to 3D printing nailing process simulation entity model at preoperative,and compared with the control in the operation can effectively improve the effect of nailing.