Winner of the Sanford J. Larson, MD, PhD, Award, Daipayan Guha, MD, presented his research, Optical Topographic Imaging for Intra-Operative Three-Dimensional Navigation in the Cervical Spine: Accuracy Validation and Initial Clinical Feasibility, during the 2017 American Association of Neurological Surgeons (AANS) Annual Scientific Meeting.
Computer-assisted, three-dimensional navigation may guide spinal instrumentation. Current systems are hampered by cumbersome registration and inability to account for intraoperative tissue movement. A novel optical topographic imaging (OTI) system was developed for craniospinal neuronavigation and has been described previously in the thoracolumbar spine. In this study, the authors validate its accuracy in the mobile cervical spine.
Initial validation was performed in four human cadavers. Intraoperative registration was performed to thin-slice preoperative CT imaging. A tracked drill-guide was used to navigate screw tracts at all levels. Lateral mass screws were placed at C1 and C3-6, pars screws at C2 and pedicle screws at C7. Navigation data were compared to screw positions on postoperative CT imaging, and the absolute translational and angular deviations computed. Clinical validation was subsequently performed in six patients undergoing open posterior cervical instrumentation.
Fifty-three cadaveric screws were analyzed; five lateral mass screws at C1 and 32 at C3-6, eight pars screws at C2 and eight pedicle screws at C7. In hierarchical linear modelling, adjusting for differences between cadavers, C7 pedicle screws demonstrated decreased axial translational error relative to all other screws. Twenty-two clinical screws were analyzed: two pars screws at C2, 14 lateral mass screws at C3-5 and six pedicle screws at C7.
Optical machine-vision is a novel navigation technique allowing efficient initial and repeat registration. Accuracy, even in the more-mobile cervical spine, is comparable to current spinal neuronavigation systems.