Clinical pedicle screw accuracy and deviation from planning in robot-guided spine surgery: robot-guided pedicle screw accuracy.
METHODS
A retrospective chart review was performed for 112 consecutive minimally invasive spinal surgery patients who underwent pedicular screw fixation in a community hospital setting.


OBJECTIVE
To assess the clinical accuracy and deviation in screw positions in robot-assisted pedicle screw placement.


BACKGROUND
Accuracy of pedicle screw placement in in vivo studies varies widely, especially when minimally invasive techniques are used. Robotic guidance was recently introduced to increase screw placement accuracy but still reported accuracies vary.


METHODS
Reproducibility of the surgeon's plan using robotic guidance was assessed by fusing individual vertebras from the preoperative computed tomography (CT) containing the planning with a postoperative CT. Deviation in entry point and difference in angle of insertion was measured on axial and sagittal planes. Grading of pedicle screw placement was performed on postoperative CTs using the Gertzbein-Robbins classification.


RESULTS
CT-to-CT fusion succeeded for 178 screws, but these appeared to be random, with no apparent selection bias. Mean deviation in entry point was 2.0 ± 1.2 mm. Mean difference in angle of insertion was 2.2° ± 1.7° on the axial plane and 2.9° ± 2.4° on the sagittal plane. Assessment of pedicle screw accuracy showed that 477 of 487 screws (97.9%) were safely placed (<2 mm, category A+B), 8 screws in category C and 1 in category D. None of the screws necessitated resurgery for revised placement.


CONCLUSIONS
Preoperative planning of robotic guidance is reproduced intraoperatively within acceptable deviations. We conclude that robotic guidance allows for highly accurate execution of the preoperative plan, leading to accurate screw placement.


METHODS
3.
*Medisch Spectrum Twente, Department of Neurosurgery, Enschede, The Netherlands; and †University of Twente, MIRA Institute for Biomedical Technology and Technical Medicine, Enschede, The Netherlands.
Joris D
JD
van Dijk
Roy P J
RP
van den Ende
Stefano
S
Stramigioli
Matthias
M
Köchling
Norbert
N
Höss
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000295:instrumentation; D065289:Pedicle Screws; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012371:Robotics / Q000295:instrumentation; D013123:Spinal Fusion / Q000379:methods; D025321:Surgery, Computer-Assisted / Q000379:methods; D013904:Thoracic Vertebrae / Q000601:surgery*