3D-printed guiding templates for improved osteosarcoma resection

Abstract

Osteosarcoma resection is challenging due to the variable location of tumors and their proximity with surrounding tissues. It also carries a high risk of postoperative complications. To overcome the challenge in precise osteosarcoma resection, computer-aided design (CAD) was used to design patient-specific guiding templates for osteosarcoma resection on the basis of the computer tomography (CT) scan and magnetic resonance imaging (MRI) of the osteosarcoma of human patients. Then 3D printing technique was used to fabricate the guiding templates. The guiding templates were used to guide the osteosarcoma surgery, leading to more precise resection of the tumorous bone and the implantation of the bone implants, less blood loss, shorter operation time and reduced radiation exposure during the operation. Follow-up studies show that the patients recovered well to reach a mean Musculoskeletal Tumor Society score of 27.125.

Figure 1. Schematic illustration of the general idea of this study.

CT scan is first performed on the tumorous bone (A). The CT scan image is then used to reconstruct a 3D model of the tumorous bone using Simpleware software (B). The 3D model is then used to design a guiding template using reverse engineering software (C). The model of the guiding template is then used to fabricate the template by 3D printing (D). The 3D printed template is characterized by SEM imaging (E) and biomechanical testing (F). The template is further used to guide the surgery of osteosarcoma (G). The patient is followed after surgery to test the efficacy of the surgery (H).

Figure 2. Three-dimensional reconstruction of osteosarcoma bone models using Scan IP software.

(A) Frontal view. (B) Lateral view.

Figure 3. A 21-year-old patient with osteosarcoma of the distal femur.

(A) Anteroposterior CT scan image. (B) MRI image. Both CT and MRI images revealed an osteosarcoma in the left distal femur. (C) Merging of the CT and MRI images for the delineation of the tumor. (D) The 3-D bone tumor model reconstructed from the merged CT and MRI image with the tumor profile highlighted in red.

Figure 4. Design of the guiding template on the basis of the 3D tumorous bone shown in Fig. 1 using reverse engineering software according to anatomical position.

(A) The three-dimensional computer model of the guiding template. (B) The guiding template fitted the distal femur perfectly. (C) Target resection planes were designed according to the osteosarcoma (red) with a safe margin.

Figure 5

3D printed guiding template (A) and the combination of the template and femur (B) shows that the guiding template fitted the rapid prototyping model of the distal femur perfectly.

Figure 6. The guiding template applied in the operation on an 18-year-old man with a distal femur.

(A) 3D printed guiding template fitted with the femur model. (B) The guiding template fitted perfectly with the distal femur during the operation and provided anatomical guidance for a safe osteotomy line. (C) Precise excision of the tumorous bone according to the surgery guided by the template. (D) The pruned allografted bone to be implanted. (E) The allograft was implanted into the bone defect. (F–H) The patient was healed (F, Supine view; G, Flexion view; H, Standing view).

Figure 7. Surface morphology of the 3D guiding template surface.

Figure 8. The stress-strain curve of the template.

Figure 9. Cell proliferation on the guiding templates after 1, 3 and 5 days of incubation was measured by colorimetric CCK-8 assay.

The group cultured in the absence of the guiding templates but with α-MEM supplemented with 10% FBS serving as a control. The results shown are the means ± standard deviation of three separate experiments performed in triplicate.

Figure 10. X-ray image showing that the interlocking intramedullary nails were excellent, with high stability.

(A) Preoperative and (B) postoperative radiographs (Left, front view; right, lateral view).