Use of image-guided robotic-assisted drilling for transcondylar screw placement in the canine humerus.

Objective: To determine if a novel robotic system has comparable positional and angular accuracy to that achievable with patient-specific guides (PSG) when used for transcondylar screw (TCS) placement in the canine humerus.

Study design: Experimental laboratory study.

Sample population: A total of 32 synthetic humeral models (16 per group).

Methods: Bone models were three-dimensional (3D)-printed and drilled with the aid of a custom PSG or with the assistance of an image-guided surgical robot. A 2.5-mm hole was drilled medial to lateral and the entry point, exit point and angular trajectory of the drill hole were measured on postoperative computed tomography (CT) scans. Absolute differences between planned and actual positions and trajectories were compared between PSG and Robot groups.

Results: None of the drill holes in this study violated the articular surface of the humerus. Entry point positioning was significantly more accurate in the PSG group, but drill hole trajectories (angulation) were more accurate in the Robot group. Exit point positioning was similar in the two groups.

Conclusion: Robotic assistance enables safe placement of drill holes for TCS. PSG enable more accurate drill entry, but robotic assistance allows for more accurate overall drill hole trajectory.

Clinical significance: Robotic assistance allows for accurate and safe drilling of screw holes for TCS placement in the humerus. The robotic procedure allows for a more limited surgical exposure, but the technical feasibility and outcomes associated with this approach should now be evaluated in cadavers before moving to clinical evaluation in live patients.