Fig. 3From: Rates and risk factors of intrapedicular accuracy and cranial facet joint violation among robot-assisted, fluoroscopy-guided percutaneous, and freehand techniques in pedicle screw fixation of thoracolumbar fractures: a comparative cohort studyProximal facet joint violation in accordance with the Babu scale. A Grade 0, screw not in facet, transverse position (a); and Grade 1, screw in lateral facet but not in facet articulation, transverse position (b); B Grade 2, penetrating facet articulation less than 1Â mm, transverse position (c); and Grade 3, traveling within facet articulation, transverse position (d)Back to article page