Abstract:

BACKGROUND: Atlantoaxial pedicle screw is thought to be the most stable instrumentation for reconstructive surgery of the cervical spine. However, because of the unresolved and inherent risk of neurovascular injuries due to screw perforation, it remains not widespread nowadays despite the excellent biomechanical property. The accuracy of atlantoaxial pedicle screw placement needs to be improved.
OBJECTIVE: To explore the principle of spinal surgical navigation surgery robot atlantoaxial transpedicular dual placement with the aim of establishing a high accurate and easily operation atlantoaxial transpedicular dual placement technique.
METHODS: Prior to surgery, on CT scanning image bisecting atlantoaxial pedicle in superior/inferior, each point was selected on both sides of sagittal line respectively, which located on vertebra arc-shaped epiphyseal line. The line segment across the above two points was named tranverse line (TL). The midline cuts TL and the line tangent to the furthest point of at the back of atlantoaxial respectively, and the line segment across the two points was named perpendicular line (PL), thus TL and PL which have known length and orthogonality were set on vertebra. Intraoperatively, one tranverse line and one perpendicular line with the same length to TL and PL respectively were set in vitro on dual placement manipulator. Under X-ray lateral fluoroscopy, the two tranverse lines and two perpendicular lines were matched respectively, the tip of manipulator’s registration arm contact tightly the surface of vertebra, accordingly, atlantoaxial sagittal plane, coronal plane, horizontal plane were confirmed. The length between both guide-wires’ tip was set equally to the length of both entry points, the angle between the centre axis line of pedicle and the midline equally to preoperative measurements, dual placement along the centre axis line of pedicle can be conducted with spinal navigation surgery robot with real-time monitoring.
RESULTS AND CONCLUSION: With the application of spinal navigation surgery robot to dual placement on atlantoaxial vertebra, when inside and outside traverse line, perpendicular line were matched respectively, and the tip of manipulator`s registration arm contact tightly arc-shaped surface of vertebra, the tips of both guide-wires locate nowhere but the entry points of both pedicles. With real-time monitoring, dual placement along the center axis line of pedicle can be performed with spinal navigation surgery robot, which can provide accurate implantation of atlantoaxial placement.