Purpose or Case Report: We describe a process for pre-operative virtual surgical planning and creation of patient specific surgical guides for bony tumor resection in pediatric orthopedic surgery and demonstrate a case in which this process was used for successful surgical guidance.
Methods & Materials: Herein we describe the general process for creating a virtual surgical plan (VSP) and show an example of a scapula tumor resection aided by a 3D printed surgical guide.First, a virtual 3D model of the bony anatomy is reconstructed using pre-operative CT scan images.MRI sequences that clearly delineate the tumor margins then are chosen to reconstruct the tumor.Using segmentation, region growing and 3D modeling algorithms of MIMICS^TM (Materialise,Belgium),3D models of the region of interest (ROI) are created.The CT and MRI sequences are fused using the image registration algorithms in MIMICS^TM.VSP and creation of patient specific surgical guides:The registered 3D models are imported into Geomagic Freeform (3D systems,SC,USA).The program has a force feedback haptic phantom and tools for cutting, moving, rotating, and creation of offsets, etc. Resection(osteotomy)planes are created on the model after due consideration of the safety margin required for the type of tumor,blood vessels in the line of osteotomy, preservation of musculoskeletal function, and any other clinical requirements of the surgeon.The planes are then used to cut the models, simulating the surgical procedure.Open type or closed guides are created depending on the anatomical location,tumor type,surgical plan and surgeon’s preferences.Guides are designed as an offset of the remaining normal bone along the osteotomy plan. Screw holes for fixing the guide to the anatomical region of resection are provided.Bone thickness in the ROI is provided ahead of surgery for appropriate planning and preparedness.3D Printing:Designed guides are 3D printed with autoclavable materials such as DentalSG™resin,ULTEM 9085, and Polyamide or with MED610–Sterrad sterilization.Patient specific surgical guides so produced are used in the sterile field and fitted on the ROI.The VSP resection plan is transferred to the OR and executed precisely.
Results: We utilized this procedure for successful resection of Ewing’s Sarcoma of the scapula in a 12-year-old, preserving as much of the patient’s native scapula as safely feasible.
Conclusions: This process can lead to better safety and quality procedures, eventually leading to better clinical outcomes.