3-Dimensional printing templates guiding versus free hand technique for cervical lateral mass screw fixation: A prospective study.

OBJECTIVE: In this randomized, single blind and controlled study, the feasibility and precision of 3-dimensional printing templates for cervical lateral mass screw insertion was evaluated. METHODS: A total of 6 patients (72 screws), who were diagnosed with cervical spondylotic myelopathy (CSM) and developmental cervical spinal stenosis, were randomly divided into A and B two groups. All subjects underwent modified posterior surgery with using cervical lateral mass screws insertion (C4-C6). Group A underwent surgeries with screw insertion assisted by the guidance of 3-dimensional printing templates and Group B underwent surgeries with screw insertion by freehand. The criteria of the accuracy of screw placement were set as the main evaluation indicators. RESULTS: There was no significant difference between the 2 groups in age, improvement rate of JOA, operation time and blood loss. According to Bayard's criteria, 32 screws (88.9%) were described as "acceptable" in group A and 22 screws (61.1%) were described as "acceptable" in Group B (P < 0.05). Based on our criteria, the "excellent and good" rate of screws was 83.3% in group A and 47.2% in Group B, respectively (P < 0.05). The precision of screws' location in Group A was superior to that in Group B. CONCLUSIONS: 3-Dimensional printing screw insertion templates may achieve (1) comprehensive visualization of the cervical vertebrae and lateral mass and the individual surgical planning using the 3-dimensional model preoperatively. (2) increasing the accuracy of cervical lateral mass screw insertion.