Fig. 1From: Safety and risk factors of TINAVI robot-assisted percutaneous pedicle screw placement in spinal surgeryIntra-pedicular accuracy according to the Gertzbein–Robbins scale in robot-assisted technique. A. Grade A, screw position completely within the pedicle (a); Grade B, cortical breach of 0.94 mm (b); B. Grade B, cortical breach of 1.78 mm (c); Grade C, cortical breach of 2.63 mm (d); C. Grade D, cortical breach of 5.29 mm (e); and D. Grade E, cortical breach of 7.53 mm (f)Back to article page