(I-513) Advances in Virtual Cutting Guides and Stereotactic Navigation for Complex Tumor Resections of the Sacrum and Pelvis: Case Series with Long-term Follow-up
PGY-5, Orthopedic Surgery Houston Methodist Hospital
Introduction: Using virtual cutting guides to perform navigated osteotomies may be a reliable method for safely obtaining negative margins in complex tumor resections of the sacrum and pelvis. This study provides a detailed description of this technique and presents short-term outcomes of its application.
Methods: Patients who underwent an en bloc tumor resection of the sacrum and/or pelvis using virtual cutting guides with a minimum follow-up of two years were retrospectively analyzed and included in the study. Preoperative computer-assisted design (CAD) was used to design osteotomies in each case. Segmentation, delineating the tumor from normal tissue, was performed by the senior author using pre-operative CT scans and MRI. Working with a team of biomedical engineers, virtual surgical planning was performed to create osteotomy lines on the preoperative CT. These objects were saved as objects in an STL file format. The STL file was then uploaded into the stereotactic navigation system and overlaid on to the intra-operative CT. The pre-planned osteotomy lines were visualized as “virtual cutting guides” providing real-time stereotactic navigation. A precision ultrasound-powered cutting tool was then integrated into the navigation system and used to perform the osteotomies in each case.
Results: Six patients (mean age 52.2 +/- 17.7 years) were included in the study. One patient had primary osteosarcoma involving the sacrum and ilium, one patient had radiation-induced osteosarcoma involving the sacrum and ilium, three patients had primary chondrosarcoma involving the pelvis and/or sacrum, and one patient had secondary chondrosarcoma involving the ilium. Negative margins were achieved in all patients with no intraoperative complications. Mean follow-up was 38.0 +/- 6.5 months (range, 24.8-42.2). Mean operative time was 1229 min (range, 522-2063). There were no cases of 30-day readmissions, 30-day reoperations, or 2-year mortality. One patient was complicated by flap necrosis, which was successfully treated with irrigation and debridement and primary closure. One patient had local tumor recurrence at final follow-up and two patients are currently undergoing treatment for metastatic disease.
Conclusion : Using virtual cutting guides to perform navigated osteotomies is a safe technique that can safely and reliably obtain negative margins in complex tumor resections of the sacrum and pelvis.
