Fluoroscopically Calibrated 3D-Printed Tools Increase Osteotomy Precision During Tumor Resection Near Joints

Joint-Preserving Surgery

odern imaging techniques and computer modeling allow doctors to determine the exact boundaries of osteosarcomas in advance, creating a detailed surgical plan for tumor resection. This helps preserve the patient's original joint and its function.

Increasingly, surgeons are using a combination of advanced imaging techniques and 3D printing to create specialized tools designed for individual patients. During surgery, these tools are attached to the operated bone, allowing precise tumor resection at specific locations and angles.

Advanced imaging techniques also reveal even minor inaccuracies in what may initially appear to be a flawless surgical plan. For example, if the bone surface is not properly prepared and has soft tissue remnants, minor discrepancies can appear in the positioning of the tool. Maximum precision is crucial for a successful surgery.

Fluoroscopic Calibration of Positional Markers

A research team from Peking University has developed a personalized 3D-printed tool for osteosarcoma resection that can be accurately positioned using fluoroscopically calibrated markers.

Essentially, this tool is a typical 3D-printed surgical instrument that incorporates several metal pins. These pins serve as pre-calibrated markers, oriented in different positions and directions.

The surgeon places the tool at the surgical site and then uses an X-ray, available in most operating rooms, to adjust its position until all markers appear as small dots on the X-ray image. If any marker appears as a line, its positioning is inaccurate.

Testing on Simulated Operations

The new tool was tested in three series of simulated osteotomy operations using three synthetic models of the left knee joint (SYNBONE) in each series. The first three procedures were performed by a surgeon using the freehand method, the next three with conventional custom tools without calibration markers, and finally with tools containing fluoroscopically calibrated markers. The results were evaluated based on post-resection CT scans and statistical ANOVA variance analysis.

Patient-Specific Tools

Resections using the fluoroscopically calibrated tool showed an average cutting position deviation of 2.66 mm. With conventional guide tools, the average deviation was 4.58 mm, and using the freehand method, it was 6.36 mm. Similar deviations were observed in measurements of resection depth and angle accuracy.

According to the study’s authors, the use of fluoroscopically calibrated 3D-printed tools customized for each patient significantly improves osteotomy accuracy during tumor resection near joints. Moreover, compared to conventional tools, the calibrated tool requires minimal removal of surrounding soft tissues, contributing to better wound healing. The use of calibrated tools only slightly increases the time and cost of manufacturing and preoperative preparation compared to conventional tools.

However, the study's authors acknowledge that their research did not include cases where the tumor also affected soft tissues around the bone. Additionally, osteosarcomas can occur in areas other than near joints, such as in the pelvic region. The research also did not consider other rapidly evolving treatment options, such as robot-assisted surgery. The researchers emphasize that further experiments and clinical studies are needed to confirm the efficacy and applicability of fluoroscopically calibrated tools.

Source: Wang, C., Huang, S., Yu, Y., et al. Fluoroscopically calibrated 3D-printed patient-specific instruments improve the accuracy of osteotomy during bone tumor resection adjacent to joints. 3D Print Med 2024 Apr 24; 10 (1): 15, doi: 10.1186/s41205-024-00216-z.