Surgical Technique: Computer-generated Custom Jigs Improve Accuracy of Wide Resection of Bone Tumors

Abstract

Background Manual techniques of reproducing a preoperative plan for primary bone tumor resection using rudimentary devices and imprecise localization techniques can result in compromised margins or unnecessary removal of unaffected tissue. We examined whether a novel technique using computer-generated custom jigs more accurately reproduces a preoperative resection plan than a standard manual technique. Description of TechniqueUsing CT images and advanced imaging, reverse engineering, and computer-assisted design software, custom jigs were designed to precisely conform to a specific location on the surface of partially skeletonized cadaveric femurs. The jigs were used to perform a hemimetaphyseal resection. Methods We performed CT scans on six matched pairs of cadaveric femurs. Based on a primary bone sarcoma model, a joint-sparing, hemimetaphyseal wide resection was precisely outlined on each femur. For each pair, the resection was performed using the standard manual technique on one specimen and the custom jig-assisted technique on the other. Superimposition of preoperative and postresection images enabled quantitative analysis of resection accuracy. Results The mean maximum deviation from the preoperative plan was 9.0 mm for the manual group and 2.0 mm for the custom-jig group. The percentages of times the maximum deviation was greater than 3 mm and greater than 4 mm was 100% and 72% for the manual group and 5.6% and 0.0% for the custom-jig group, respectively. Conclusions Our findings suggest that custom-jig technology substantially improves the accuracy of primary bone tumor resection, enabling a surgeon to reproduce a given preoperative plan reliably and consistently.

Patient-specific instrument can achieve same accuracy with less resection time than navigation assistance in periacetabular pelvic tumor surgery: a cadaveric study

“…The result concurred with the accuracy of the two techniques reported in other clinical, sawbone or cadaveric studies [5,11,19,[22][23][24]. When we compared the accuracy between the two techniques in simulated pelvic bone resections, no statistical difference was noted.…”

“…Although the planes of pelvic resection were different from those in this study, the pelvic sawbone study by Cartiaux et al [19,22] showed a similar trend of mean time required for the bone resection, 49 min for navigation assistance versus 6.9 min in PSI assistance. The greater operative time in the navigation group was due to the fact that time was required for the placement of patient tracker, system calibration and image-to-patient registration prior to the navigated bone resections.…”

“…Second, there is no control group of using conventional manual technique for comparison in this study. Third, to access the accuracy of reproducing the surgical planning using the two techniques, we only calculated the absolute distance between the achieved resection plane and the corresponding planned one but did not measure the angular deviation between the two planes as used in the study by Khan et al [22]. We found it was difficult and prone to manual error to determine the best-fit plane for the achieved resection.…”

Use of Computer Navigation in Orthopedic Oncology

“…Tumor patient-specific instruments (PSIs) were recently reported in bone tumor surgery [28•, 29•, 30]. This approach can achieve accuracy similar to that of navigational guidance, but it greatly reduces the operating time and can confine the bone saw along the planned plane of resection.…”

Computer-aided resection and endoprosthesis design for the management of malignant bone tumors around the knee: outcomes of 12 cases

“…Reports by Wong et al [10,13] and Khan et al [11] have indicated that computer-assisted methods can improve the accuracy of resection of malignant bone tumors. Similarly, other authors have reported the utility of CAD for custom endoprosthesis construction [4,18,19].…”