ABSTRACT
Objectives:To explore the accuracy of pedicle screw placement assisted with improved 3D-print-ed drill guiding template in cervical spine.Methods:The clinical data of 60 patients undergone posterior cervical pedicle screw placement in our hospital between January 2016 and January 2023 were analyzed retro-spectively,including 30 males and 30 females with an average age of 17-84 years(58.7±13.8 years).The pa-tients were divided into guiding template group and free-hand group based on whether the guiding template was used to assist the placement of screws or not.The improved 3D-printed guiding template was used to assist cervical pedicle screw placement in the guiding template group(n=30),and the self-made angular-ruler was used in the free-hand group(n=30).There was no significant difference in age,gender ratio,and preoper-ative diagnosis between the two groups(P＞0.05).Cervical CT scan was performed at one week after surgery,and the accuracy of pedicle screw placement was evaluated according to the Kaneyama standard:Grade 0,the screw was completely in the pedicle;Grade 1,the size of screw penetrating the cortex＜50%of the screw diameter;Grade 2,the size of screw penetrating the cortex≥50%of the screw diameter but not com pletely out;Grade 3,the screw was completely on the outside of the pedicle.The accuracy of pedicle screw placement(ratio of grades 0 and 1)and complications such as vascular and nerve injury,incision infection,cerebrospinal fluid leakage,screw loosening and breakage caused by screw misplacement were recorded.Re-sults:A total of 152 pedicle screws were placed in the guiding template group,including 74 screws of grade 0,68 of grade 1,10 of grade 2 and 0 of grade 3,with an accuracy of screw placement of 93.4%.A total of 136 pedicle screws were placed in free-hand group,including 53 screws of grade 0,61 of grade 1,18 of grade 2 and 4 of grade 3,with an accuracy of screw placement of 83.8%.The accuracy of screw placement in the guiding template group was significantly higher than that in the free-hand group(P＜0.05).There were no related complications such as vascular and nerve injury,incision infection and cerebrospinal fluid leakage caused by misplacement of pedicle screws.The patients were followed up for 5-29 months(14.2±7.7months),and there were no complications such as screw loosening or breakage.Conclusions:Improved 3D-printed drill guiding template can improve the accuracy of pedicle screw placement in cervical spine.
ABSTRACT
Objectives:To explore the safety and accuracy of subaxial cervical pedicle screw(CPS)insertion assisted with optimized 3D-printed drill guiding template(DGT).Methods:A retrospective study was conducted to analyze the clinical data of 42 patients aged 32-74 years(50.1±9.8 years)who underwent posterior cervi-cal pedicle screw intemal fixation between August 2016 and October 2022.The patients were followed up for 13-25 months(19.6±3.2 months).They were divided into two groups of guiding template group(n=22)and free-hand group(n=20)according to the method of pedicle screw insertion.In the guiding template group,the sub-axial CPSs insertions were assisted with 3D-printed DGT,designed individually for each patient based on the design scheme of an optimized pedicle drill guiding template,and the patients consisted of 12 males and 10 females,among which 6 patients were with cervical spine injury or spinal cord injury,9 were with ossifica-tion of posterior longitudinal ligament(OPLL),5 were with intraspinal tumor,and 2 were with cervical spondy-lotic myelopathy.In the free-hand group,the subaxial CPSs were inserted with free hand according to the cervical parameters such as pedicle angle and diameter on the CT images measured before operation,and the patients consisted of 10 males and 10 females,among which 4 patients were with cervical spine injury or spinal cord injury,10 with OPLL,5 with intraspinal tumor,and 1 with cervical spondylotic myelopathy.There were no significant differences in sex,age,disease,and preoperative visual analogue scale(VAS)score and Japanese Orthopaedic Association(JO A)score between the two groups(P＞0.05).The operative time,intraopera-tive blood loss,and postoperative 12 months of VAS and JOA scores were recorded and compared.CT scan was performed at 1 week after operation on cervical spine,and the accuracy of pedicle screw placement was evaluated in accordance with Kaneyama's evaluation method:Grade 0,screw was contained in the pedicle;Grade 1,screw penetrated pedicle＜50％of the screw diameter;Grade 2,screw penetrated pedicle＞50％of the screw diameter;Grade 3,screw completely penetrated the pedicle.Grades 0 and 1 were considered accurate placement,and grades 2 and 3 were considered misplacement.The perioperative complications were recorded for each patient in the two groups.Results:The operative time,intra-operative blood loss in guiding template group(102.2±16.1min,89.3±17.7mL)were statistically less than those in free-hand group(142.8±20.9min,133.3±34.0mL)(P＜0.01).A total of 216 CPSs were placed:118 in the guiding template group,including 90 screws of grade 0,22 screws of grade 1,5 screws of grade 2,1 screw of grade 3,with an accuracy rate of 94.9％(112/118);And 98 in the free-hand group,including 48 screws of grade 0,36 screws of grade 1,10 screws of grade 2,and 4 screws of grade 3,with an accuracy rate of 85.7％(84/98).The accuracy rate of pedicle screw insertion was significant higher in the guiding template group than that in the free-hand group(P＜0.05).No major neurovascular complications nor internal fixation loosening or breakages were observed in two groups of patients.At 12 months after operation,the VAS score in both groups was statistically less than that before operation(P＜0.01),and the JOA score in both groups was statistically more than that before opera-tion(P＜0.01),and there were no significant differences in VAS score and JOA score between groups,respec-tively(P＞0.05).Conclusions:The optimized design scheme of 3D-printed DGT is helpful in improving the ac-curacy and safety of subaxial CPS insertion.