A novel intraoperative method to project osteotomy lines for accurate resection of primary bone sarcomas.

Background: Accurate reproduction of a preoperative plan is critical in wide resection of bone sarcomas. Recent advances in computer navigation and 3D-custom jigs have increased resection accuracy, although with certain practical drawbacks.
Methods: We developed a novel "projector method" that projects the preoperative osteotomy lines onto the bone. A sawbone study was conducted to evaluate accuracy in reproducing preoperative resection plans. An additional cadaver experiment was conducted to evaluate feasibility in a more realistic operating room setting.
Results: Based on the results of experiments conducted on sawbones, the proposed light projector method was more accurate at depicting desired osteotomy lines than a traditional manual method, reducing the corner deviation from 2.53 mm to 0.35 mm, angular deviation from 2.10° to 0.31°, and point deviation from 4.66 mm to 0.48 mm (p < 0.001). Results of the cadaver experiment were consistent with those of sawbone experiments. Conclusions: The new projector method can accurately assist surgeons in visualizing the preoperative plan of osteotomy lines accurately in surgery.