Computer-assisted Navigation in Bone Tumor Surgery: Seamless Workflow Model and Evolution of Technique

Abstract

Background Computer-assisted navigation was recently introduced to aid the resection of musculoskeletal tumors. However, it has not always been possible to directly navigate the osteotomy with real-time manipulation of available surgical tools. Registration techniques vary, although most existing systems use some form of surface matching. Questions/purposes We developed and evaluated a workflow model of computer-assisted bone tumor surgery and evaluated (1) the applicability of currently available software to different bones; (2) the accuracy of the navigated excision; and (3) the accuracy of a new registration technique of fluoro-CT matching. Methods Our workflow involved detailed preoperative planning with CT-MRI image fusion, three-dimensional mapping of the tumor, and planning of the resection plane. Using the workflow model, we reviewed 15 navigation procedures in 12 patients, including four with joint-saving resections and three with custom implant reconstructions. Intraoperatively, registration was performed with either paired points and surface matching (Group 1, n = 10) or a new technique of fluoro-CT image matching (Group 2, n = 5). All osteotomies were performed under direct computer navigation. Postoperatively, each case was evaluated for histologic margin and gross measurement of the achieved surgical margin. Results The margins were free from tumor in all resected specimens. In the Group 1 procedures, the correlation between preoperative planned margins and actual achieved margins was 0.631, whereas in Group 2 procedures (fluoro-CT matching), the correlation was 0.985. Conclusions Our findings suggest computer-assisted navigation is accurate and useful for bone tumor surgery. The new registration technique using fluoro-CT matching may allow more accurate resection of margins.

What Is the Expected Learning Curve in Computer-assisted Navigation for Bone Tumor Resection?

“…If we analyze previous publications, this type of procedure has a risk of failures at the beginning of the learning curve [3,16]. Another report describes that technical problems occurred in 20% of the analyzed series [18]. The authors indicated that they only used a mean of 20 points during surface registration, which could be the reason for such a high frequency of intraoperative problems.…”

“…Intraoperative registration of the patient to the patient images is the key step in the navigation process [18] and is calculated by the navigation system software. These data were obtained intraoperatively in the navigation system after point and surface registration and were registered in all the cases in which navigation was performed.…”

“…This surgical assistance is becoming more frequently used in limb salvage surgery to preserve as much host tissue as possible without compromising tumor margins and may help surgeons perform more accurate resections [11,15,16,18]. However, previous reports about navigation in trauma and arthroplasty have suggested that computer assistance techniques do not improve patient-reported outcomes and that these techniques add surgical time [6,8,13,20].…”

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

“…An important future study should compare the accuracy of recently introduced computer-navigated resections [8,28,32] with that of custom jig-assisted resections. For certain bone tumor resections, computer navigation has enabled the surgeon to achieve negative margins while also Fig.…”

“…preserving key anatomic structures such as joint surfaces [8,28,32]. We surmise that the custom-jig technique may produce more accurate results than the computer-navigated technique.…”