Can Navigation Improve the Ability to Achieve Tumor-free Margins in Pelvic and Sacral Primary Bone Sarcoma Resections? A Historically Controlled Study

Abstract

Background: Anatomic and surgical complexity make pelvic and sacral bone sarcoma resections challenging. Positive surgical margins are more likely to occur in patients with pelvic and sacral bone sarcomas than in those with extremity sarcomas and are associated with an increased likelihood of local recurrence. Intraoperative navigation techniques have been proposed to improve surgical accuracy in achieving negative margins, but available evidence is limited to experimental (laboratory) studies and small patient series. Only one small historically controlled study is available. Because we have experience with both approaches, we wanted to assess whether navigation improves our ability to achieve negative resection margins.

Questions/purposes: Are navigated resections for pelvic and sacral primary bone sarcomas better able to achieve adequate surgical margins than nonnavigated resections?

Methods: Thirty-six patients with pelvic or sacral sarcomas treated with intraoperative navigation were retrospectively compared with 34 patients undergoing resections without navigation. All patients underwent resections between 2000 and 2017 with the intention to achieve a wide margin. Patients in the navigation group underwent surgery between 2008 and 2017; during this period, all resections of pelvic and sacral primary bone sarcomas with the intention to achieve a wide margin were navigation-assisted by either CT fluoroscopy or intraoperative CT. Patients in the control group underwent surgery before 2008 (when navigation was unavailable at our institution), to avoid selection bias. We did not attempt to match patients to controls. Nonnavigated resections were performed by two senior orthopaedic surgeons (with 10 years and > 25 years of experience). Navigated resections were performed by a senior orthopaedic surgeon with much experience in surgical navigation. The primary outcome was the bone and soft-tissue surgical margin achieved, classified by a modified Enneking system. Wide margins (≥ 2 mm) and wide-contaminated margins, in which the tumor or its pseudocapsule was exposed intraoperatively but further tissue was removed to achieve wide margins, were considered adequate; marginal (0-2 mm) and intralesional margins were considered inadequate.

Results: Adequate bone margins were achieved in more patients in the navigated group than in the nonnavigation group (29 of 36 patients [81%] versus 17 of 34 [50%]; odds ratio, 4.14 [95% CI, 1.43-12.01]; p = 0.007). With the numbers available, we found no difference in our ability to achieve adequate soft-tissue margins between the navigation and nonnavigation group (18 of 36 patients [50%] versus 18 of 34 [54%]; odds ratio, 0.89 [95% CI, 0.35-2.27]; p = 0.995).

Conclusions: Intraoperative guidance techniques improved our ability to achieve negative bony margins when performing surgical resections in patients with pelvic and sacral primary bone sarcomas. Achieving adequate soft-tissue margins remains a challenge, and these margins do not appear to be influenced by navigation. Larger studies are needed to confirm our results, and longer followup of these patients is needed to determine if the use of navigation will improve survival or the risk of local recurrence.

Level of evidence: Level III, therapeutic study.

Fig. 1

This flowchart shows how patients were included in our study.

Fig. 2

These images show preoperative surgical planning for tumor resection in a 34-year-old woman with a Grade II chondrosarcoma in the periacetabular region of the right side of the pelvis. (A) Preoperative MR images demonstrate a high-grade tumor in the right periacetabular region. (B) Computer screenshots of the navigation software show fusion of the MRI (orange) and CT scans (blue). (C) This screen image from the navigation system shows the mapped tumor in orange and the planned safety margin in blue, in three planes (clockwise from top left: three-dimensional reconstruction in the transverse, sagittal, and coronal planes). (D) This image shows the planning of a LUMiC® prosthesis (Implantcast, Buxtehude, Germany). The LUMiC® prosthesis is a modular device and consists of a separate cup and stem, both available in different sizes and with different coatings. An AP radiograph after navigation-assisted LUMiC® endoprosthetic pelvic reconstruction after resection is shown.

Fig. 3

This figure shows the general set up of the AIRO® scanner in our operating room during surgery and intraoperative CT-based scanning. (A) This demonstrates the schematic setup of intraoperative CT-based navigation during the procedure. (B) This demonstrates the schematic setup of the intraoperative CT position during scanning. (C) This picture was made during a procedure in which intraoperative CT-based navigation was used.

Fig. 4

This shows the schematic workflow for computer-assisted orthopaedic surgery.