Image Registration Technique for Assessing the Accuracy of Intraoperative Osteotomy for Pelvic Tumors by 3D-Printed Patient-Specific Templates

The study aimed to explore the feasibility of an image registration technique for assessing the accuracy of intraoperative osteotomy of pelvic tumors by 3-dimensional(3D)-printed patient-specific templates.Patients with malignant pelvic tumors who were admitted to our hospital between March 2014 and December 2020 were retrospectively enrolled.Patients underwent hemi-pelvic resection and reconstruction by 3D-printed individualized prostheses.The registration between the designed model and the postoperative segmented model of the prosthesis was used to obtain the intraoperative osteotomy plane and reduce metal artifacts in postoperative computed tomography(CT)images.The distance and angle between the planned and actual osteotomy planes were then used to assess the accuracy of the intraoperative osteotomy.Eight patients with 13 osteotomy planes were enrolled,including four males and four females.The median age at the time of imaging examination was 44 years(range,33–54 years).All intraoperative osteotomy planes were assessed successfully.The mean distance between the planned and true intraoperative osteotomy planes was−0.69 cm(−7.5–7.35 cm),and the mean angle was 6.57°±3.36°(1.05°–11.88°).This new assessment method of registering the designed model and the postoperative CT segmented model of the prosthesis may be used to assess the accuracy of intraoperative osteotomy for pelvic tumors,using 3D printed patient-specific templates.