Virtual Planning and Allograft Preparation Guided by Navigation for Reconstructive Oncologic Surgery: A Technical Report.

ABSTRACT

INTRODUCTION: Advanced virtual simulators can be used to accurately detect the best allograft according to size and shape. STEP 1 ACQUISITION OF MEDICAL IMAGES Obtain a multislice CT scan and a magnetic resonance imaging (MRI) scan preoperatively for each patient; however, if the time between the scans and the surgery is >1 month, consider repeating the MRI because the size of the tumor may have changed during that time. STEP 2 SELECT AN ALLOGRAFT USING VIRTUAL IMAGING TO OPTIMIZE SIZE MATCHING Load DICOM images into a virtual simulation station (Windows 7 Service Pack 1, 64 bit, Intel Core i5/i7 or equivalent) and use mediCAS planning software ( medicas3d.com ) or equivalent (Materialise Mimics or Amira software [FEI]) for image segmentation and virtual simulation with STL (stereolithography) files. STEP 3 PLAN AND OUTLINE THE TUMOR MARGINS ON THE PREOPERATIVE IMAGING Determine and outline the tumor margin on manually fused CT and MRI studies using the registration tool of the mediCAS planning software or equivalent (Materialise Mimics software.). STEP 4 PLAN AND OUTLINE THE SAME OSTEOTOMIES ON THE ALLOGRAFT Determine and outline the osteotomies between host and donor using the registration tool of the mediCAS planning software or equivalent (Materialise Mimics software.). STEP 5 ASSESS THE PATIENT AND ALLOGRAFT IN A VIRTUAL SCENARIO Be sure to consider the disintegration of bone tissue that occurs during the osteotomy and corresponds to the thickness of the blade (approximately 1.5 mm). STEP 6 NAVIGATION SETTINGS A tool of the mediCAS planning software allows the virtual preoperative planning (STL files) to be transferred to the surgical navigation format, DICOM files. STEP 7 PATIENT AND ALLOGRAFT INTRAOPERATIVE NAVIGATION The tumor and allograft are resected using the navigated guidelines, which were previously planned with the virtual platform. RESULTS: The 3D virtual preoperative planning and surgical navigation software are tools designed to increase the accuracy of bone tumor resection and allograft reconstruction3.