The pedicle screw accuracy using a robotic system and measured by a novel three-dimensional method

Area of Science:

• Spine surgery
• Medical robotics
• Surgical accuracy

Background:

• Robotic systems enhance precision in medicine, particularly in spine surgery.
• Shared-control robotic systems offer "steady-hand" manipulation.
• Assessing the true accuracy of robotic instrumentation is crucial.

Purpose of the Study:

• To evaluate the spatial accuracy of pedicle screw (PS) insertion using the Mazor robotic system.
• To compare the accuracy of different registration methods (preopCT/C-arm vs. CT-to-fluoroscopy).
• To analyze screw trajectory deviations and classify error patterns.

Main Methods:

• Two cadaveric specimens (C7-S1) were used for pedicle screw (PS) insertion.
• Planning involved two registration methods: preopCT/C-arm and CT-to-fluoroscopy.
• PS insertion was performed via open and percutaneous approaches, followed by CT acquisition for accuracy assessment.

Main Results:

• CT-to-fluoroscopy registration showed superior accuracy (0.9 mm deviation) compared to preopCT/C-arm (1.7 mm deviation, p < 0.003).
• Percutaneous access was slightly more accurate than open access (1.3 mm vs. 1.7 mm).
• While 10.8% of screws were unacceptable by quantitative 3D position, nearly half (49.3%) were considered non-optimal under a rigorous inaccuracy concept.

Conclusions:

• CT-to-fluoroscopy registration significantly enhances pedicle screw accuracy in robotic spine surgery.
• A substantial proportion of pedicle screw insertions may be non-optimal, necessitating careful accuracy assessment.
• The O-arm registration method proved more accurate than preopCT/C-arm for implant placement.