Patient-specific 3D-printed Anatomical Models for Intraoperative Osteotomy Verification in Joint-sparing Surgery for Osteosarcoma: A Report of Two Cases.

BACKGROUND/AIM: Patient-specific three-dimensional (3D)-printed models have emerged as useful tools for surgical planning in orthopedic oncology. However, their use for real-time intraoperative verification of osteotomy levels during joint-sparing surgery for osteosarcoma has been rarely described. CASE REPORT: Two patients with osteosarcoma around the knee underwent joint-sparing limb-salvage surgery assisted by patient-specific 3D-printed anatomical models. In Case 1, a 16-year-old girl with proximal tibial osteosarcoma underwent wide resection and reconstruction using a frozen autograft after neoadjuvant chemotherapy. In Case 2, a 24-year-old man with proximal fibular osteosarcoma was initially considered for amputation because of extensive peritumoral edema and poor response to chemotherapy. Following additional chemotherapy, reduction of edema enabled joint-sparing resection. In both cases, patient-specific 3D models were generated from preoperative CT data using a desktop 3D printer and were used for preoperative simulation and intraoperative confirmation of osteotomy levels in combination with fluoroscopy. Negative surgical margins were achieved in both patients. At the latest follow-up (4 years and 3 years 10 months, respectively), neither local recurrence nor metastasis was observed. CONCLUSION: Patient-specific 3D-printed anatomical models provided a simple, low-cost, and practical adjunct for osteotomy planning and intraoperative verification in osteosarcoma surgery. This approach may facilitate accurate and reproducible joint-sparing limb-salvage procedures.