Surgical Simulation with Full Scale 3D Rubber-like Model for Vascularized Fibular Transplantation.

Surgical Simulation with Full Scale 3D Rubber-like Model for Vascularized Fibular Transplantation.

Introduction

Vascularized bone transplantation is challenging in that surgeons have to consider not only the arrangement and fixation of bone for optimal osteosynthesis, but also settings of the vascular pedicle and recipient vessels so as not to harm blood flow to the flap. Several reports exist regarding preoperative simulation with a 3D printed model made of hard material to plan the process and fixation of the bone graft. However, vascular settings is hardly evaluated with this type of model. We have developed a Full-scale 3D Rubber-Like (F3DR) model which is made of rubber like material and enables evaluation of soft tissue and vascular settings together with bone arrangement, and used the model in 2 cases of vascularized fibular transplantation after tibial osteosarcoma resection.

Materials and Methods

1.     F3DR model creation

Digital Imaging and Communications in Medicine (DICOM) of bones and vessels were segmented with an original image processing software, NewVES (Nagoya University, Nagoya, Japan). Then F3DR model of bone and vessel was created with Objet260 Connex2 (Stratasys, Eden Prairie, UN). This model was made of rubber-like polymer with a shore hardness of 27 and bony part (transparent) and vessels (black) were distinguished by its color.

2.     Patients

We performed vascularized fibula osteocutaneous flap transfer combined with heat-treated bone graft in 2 patients in which wide resection was performed for proximal tibia osteosarcoma. F3DR model of the tibia, fibula and arteries of lower leg in the resected side and fibula and arteries of the lower leg in the donor site bones and vessels was created and preoperative simulation was performed to confirm settings of bone, vessels and fixation plate.

Results

F3DR model was easy for processing and had moderate flexibility (Figure 1). Both bone and vessels can be easily shaped and manipulated as in the actual operation. The model simulation suggested that retrograde setting of the graft is better in terms of natural vascular passage compared to antegrade setting in both cases (Figure 2). Also, ideal shape, size as well as setting and fixation of fibular graft was confirmed by this model simulation.

Conclusion

Using the F3DR model, setting of both bone and vessels was easily simulated while preserving their positional relationship. Required length of the vessel and shape of fibular graft can be confirmed. It enables the operator and surgical team staff to perform safe and accurate operation by planning and knowing the anatomical arrangement of the tissue preoperatively. This simulation also has great potential for anatomical education and operative training in vascularized bone transplantation. 

Figure1

  

Figure 2