Computer-assisted surgery (CAS) in orthopedic oncology. Which were the indications, problems and results in our first...

to review a group of patients with primary bone tumors treated with intraoperative navigation and analyze: (1) The technical problems; (2) Indications for Computer Assisted Surgery (CAS); (3) Oncological results; (4) Non oncological complications.

All patients from a single institution who had preoperative virtual planned for an oncological primary bone resection assisted with navigation between May 2010 and July 2017 were enrolled in the study (203 patients). The use of computer-assisted surgery (CAS) was classified according to the oncologic procedure performed: (1) intralesional resections, (2) en-block resections, and (3) en-block resections + navigated allograft reconstructions.

Four patients (4/203, 2%) of the series presented technical problems which came from 2 software and 2 hardware crashes. Eight (4%) procedures were intralesional resections and no local recurrences or complications were reported in this group. Ninety-eight surgeries (49%) were pure en block resection. The pelvis and sacrum were the main location in this group (57%). All bone margins were defined negative but 2 patients presented a positive resection in the soft tissues. Infection was the most prevalent complication (16/23). Ninety-three procedures were done for en block resections + allograft reconstruction (all extremities tumor). All margins were free of tumor and non oncological rate for this group was 28%.

The main indications for CAS were malignant bone tumors resection. The technical failures precluded navigation use in 2%. CAS for pure en-block resections were mainly indicated in pelvic and sacrum tumors while en-block resection + allograft reconstruction assisted with navigation were only indicated in extremities tumors.

IV.