Fig. 2

Preoperative assessments in case 1: A 12-year-old girl with Ewing sarcoma of the pelvis (PI-II). a Preoperative magnetic resonance imaging. b) Preoperative plan involving the use of a computer navigation system. c) Preoperative computed tomography. d Checking the margin using a computer navigation system. e After osteotomy. f Freezing in liquid nitrogen