Machine-vision image guided C4-C5 unilateral cervical pedicle screw insertion: case report and review of literature.

Computer-assistance for pedicle screw insertion is becoming increasingly common. As in the case presented below, image guided neuronavigation can be used to improve the accuracy and safety of subaxial cervical pedicle screw placement, given their increased difficulty of cannulation relative to the larger pedicles in the thoracolumbar spine. A 49-year-old man presented with a traumatic sagittal split fracture of C4 (AO Classification type A4) and a left lateral mass fracture of C5 (AO Classification type F1) with anterior depression and 50% height loss. MRI revealed evidence of strain of the interspinous/supraspinous ligaments (AO Classification type B2), as well as fluid within the left C4-C5 facet joint. Along with these fractures, the young patient had Klippel-Feil syndrome with autofusion of the C2-3 posterior elements, and a left vertebral artery dissection. He had neck pain but was otherwise neurologically intact. The patient underwent machine-vision image guided C4-C5 unilateral pedicle screw insertion connected by a fixation rod for stabilization and bone graft to augment the instrumented fusion with good outcome. The use of machine vision spinal navigation was able to provide accurate and precise placement of pedicle screws without significantly increasing surgical time. This method has the potential to allow for the safe and accurate insertion of cervical pedicle screws and to reduce the rate of pedicle breach which could avoid significant neurovascular injury.