Revista de la Asociación Argentina de Ortopedia y Traumatología
versión On-line ISSN 1852-7434
RITACCO, Lucas E. et al. Virtual Reality: Application in oncologic skeletal reconstructive surgery. Presentation of a tibial osteosarcoma case. Rev. Asoc. Argent. Ortop. Traumatol. [online]. 2011, vol.76, n.1, pp. 82-87. ISSN 1852-7434.
Background: One of the major challenge for orthopedic surgery is to create a preoperative plan in a 3D virtual space and reproduce it in a 3D model. Thanks to rapid prototyping (RP) models, we can build a three-dimensional scaled bone model with a tumor inside. Our objective was to obtain segmented images from a tibial bone, with a tumor. Next, determine safe margins inside, in order to create a preoperative 3D plan. Then, print a RP model, with colors inside, and reproduce the surgery (simulation) with a navigation system. The feasibility of such procedure is based on our hypothesis, that it is possible to simulate an in vitro scenario for bone tumor surgery, and apply complex osteotomies with navigation, thus preserving healthy tissue. Methods: An 11-year old patient with knee pain, and proximal tibia osteosarcoma diagnosed by biopsy, was scanned with CT Multislice. The preoperative planning was applied using a 3D simulation platform. Two planes were created into the bone, one near the tumor, in red (3mm of unsafe margin), the other, far from the tumor, in blue (3mm of safe margin). Our RP model was created using Z-printer Spectrum Z- 510 and ZP131 powder in 1hour and 47 minutes. We printed the model in two halves, in order to print the inner colored structures, which were then attached with glue, thus obtaining the final RP bone model. The preoperative plan was masked and exported from our 3D virtual platform to the navigator. The osteotomies were applied with Stryker Navigation System II, using the planned 3D virtual path. After performing the osteotomy, the piece was separated with a saw into the two original halves. Results: The separated RP bone was used as an anatomic pathological simulated model. We could see the correct and wrong paths of the previously planned osteotomy in the 3D virtual scenario, applied with navigation. Conclusions: This novel surgery-reproducing application, is a good training for surgeons, interested in the behavior of the navigation system in oncologic surgery, and in knowing how to perform the preoperative planning in a custom scaled model using a navigated rapid prototyping model. Other interesting benefits are: pre-bending the plates to the bone shape, apply and improve planned osteotomies, plan pins' position for navigation, and check the correct margins in order to avoid mistakes in a real surgery and save OR time with a full 3D preoperative plan, combining CAD software, RP-models and navigation.
Palabras clave : Rapid prototyping; Computed-assisted surgery; 3D pre-op planning.