title: Computer-assisted tumor surgery in malignant bone tumors.
abstract: BACKGROUND
  Small recent case series using CT-based navigation suggest such approaches may aid in surgical planning and improve accuracy of intended resections, but the accuracy and clinical use have not been confirmed.
  
  
  OBJECTIVE
  We therefore evaluated (1) the accuracy; (2) recurrences; and (3) function in patients treated by computer-assisted tumor surgery (CATS).
  
  
  METHODS
  From 2006 to 2009, we performed CATS in 20 patients with 21 malignant tumors. The mean age was 31 years (range, 6-80 years). CT and MR images for 18 cases were fused using the navigation software. Reconstructed two-dimensional/three-dimensional images were used to plan the bone resection. The achieved bone resection was compared with the planned one by assessing margins, dimensions at the level of bone resection, or fitting of CAD custom prostheses. Function was assessed with the Musculoskeletal Tumor Society (MSTS) score. The minimum followup was 31 months (mean, 39 months; range, 5-69 months).
  
  
  RESULTS
  Histological examination of all resected specimens showed a clear tumor margin. The achieved bone resection matched the planned with a difference of ≤ 2 mm. The achieved positions of custom prostheses were comparable to the planned positions when merging postoperative with preoperative CT images in five cases. Three of the four patients with local recurrence had tumors at the sacral region. The mean MSTS score was 28 (range, 23-30).
  
  
  CONCLUSIONS
  CATS with image fusion allows accurate execution of the intended bone resection. It may be beneficial to resection and reconstruction in pelvic, sacral tumors and more difficult joint-preserving intercalated tumor surgery. Comparative clinical studies with long-term followup are necessary to confirm its efficacy.
  
  
  METHODS
  Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
authors.affiliation: Department of Orthopaedics and Traumatology, Prince of Wales Hospital, Shatin, Hong Kong, skcwong@ort.cuhk.edu.hk
authors.forename: Kwok Chuen
authors.initials: KC
authors.lastname: Wong
authors.forename: Shekhar Madhukar
authors.initials: SM
authors.lastname: Kumta
mesh_terms: D000293:Adolescent; D000328:Adult; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D002648:Child; D017076:Computer-Aided Design; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D010027:Osteotomy / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D011474:Prosthesis Design; D019919:Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted; D020127:Recovery of Function; D025321:Surgery, Computer-Assisted / Q000009:adverse effects / Q000295:instrumentation; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D055815:Young Adult