Background:Resection of sacral chordomas is challenging.The anatomy is complex,and there are often no bony landmarks to guide the resection.Achieving adequate surgical margins is,therefore,difficult,and the recurrence rate is high.Use of computer navigation may allow optimal preoperative planning and improve precision in tumor resection.The purpose of this study was to evaluate the safety and feasibility of computer navigation-aided resection of sacral chordomas.Methods:Between 2007 and 2013,a total of 26 patients with sacral chordoma underwent computer navigation-aided surgery were included and followed for a minimum of 18 months.There were 21 primary cases and 5 recurrent cases,with a mean age of 55.8 years old (range:35-84 years old).Tumors were located above the level of the S3 neural foramen in 23 patients and below the level of the S3 neural foramen in 3 patients.Three-dimensional images were reconstructed with a computed tomography-based navigation system combined with the magnetic resonance images using the navigation software.Tumors were resected via a posterior approach assisted by the computer navigation.Mean follow-up was 38.6 months (range:18-84 months).Results:Mean operative time was 307 min.Mean intraoperative blood loss was 3065 ml.For computer navigation,the mean registration deviation during surgery was 1.7 mm.There were 18 wide resections,4 marginal resections,and 4 intralesional resections.All patients were alive at the final follow-up,with 2 (7.7％) exhibiting tumor recurrence.The other 24 patients were tumor-free.The mean Musculoskeletal Tumor Society Score was 27.3 (range:19-30).Conclusions:Computer-assisted navigation can be safely applied to the resection of the sacral chordomas,allowing execution of preoperative plans,and achieving good oncological outcomes.Nevertheless,this needs to be accomplished by surgeons with adequate experience and skill.