Fig. 2From: Safety and risk factors of TINAVI robot-assisted percutaneous pedicle screw placement in spinal surgeryProximal facet joint violation in accordance with the Babu scale in robot-assisted technique. A. Grade 0, screw not in facet, transverse position (a); B. Grade 1, screw in lateral facet but not in facet articulation, transverse position (b); C. Grade 2, penetrating facet articulation less than 1Â mm, transverse position (c); D. Grade 3, traveling within facet articulation, transverse position (d); E. Grade 0, screw not in facet, sagittal position (e); F. Grade 1, screw in lateral facet but not in facet articulation, sagittal position (f). G. Grade 2, penetrating facet articulation less than 1Â mm, sagittal position (g); and H. Grade 3, traveling within facet articulation, sagittal position (h)Back to article page