title: Intraoperative Iso-C three-dimensional navigation in excision of spinal osteoid osteomas.
abstract: METHODS
  A prospective observational study on the use of Iso-C 3-dimensional navigated surgery in treating 4 patients with spinal osteoid osteomas by a minimally invasive approach.
  
  
  OBJECTIVE
  To report on the efficacy of Iso-C 3-dimensional intraoperative spinal navigation in excising osteoid osteomas.
  
  
  BACKGROUND
  Curative treatment of osteoid osteomas entails complete intralesional excision of the nidus. However, intraoperative localization of the nidus can be difficult, and may involve wide resection of the surrounding normal bony structure resulting in instability requiring fusion or inadvertent neurovascular injury. Computer navigation provides real-time multiplanar images of the vertebral anatomy, and has been used extensively to increase the accuracy of pedicle screw placement. However, the efficacy of this technology in intraoperative localization and excision of spinal tumors is still largely unknown.
  
  
  METHODS
  Iso-C 3-dimensional intraoperative navigation was used to localize osteoid osteomas of the spine in 4 patients. A minimally invasive reflective array, tool navigator, and a registered burr were used for localization and deroofing of the lesion, followed by curettage and high-speed burring of the cavity. Complete removal of the nidus was confirmed intraoperatively by reacquisition of data.
  
  
  RESULTS
  In all 4 patients, Iso-C 3-dimensional computer navigation was successful in accurate localization of the osteoid osteomas. The tool navigator was helpful to localize and deroof the lesion. The ability to register the burr was useful to clear the lesion without removal of any excess bone. Reregistration allowed intraoperative confirmation of adequacy of excision. Conservation of bone allowed early mobilization and also removed the need for reconstruction. Postoperative computer tomography scan done in 2 patients confirmed complete extirpation of the nidus. Histopathology confirmed the clinical diagnosis in all cases. All patients had immediate relief of the characteristic pain after surgery and were asymptomatic at 2 years follow-up.
  
  
  CONCLUSIONS
  Intraoperative Iso-C 3-dimensional navigation is useful in accurately localizing and guiding complete excision of spinal osteoid osteomas through a minimally invasive approach without compromising spinal stability.
authors.affiliation: Department of Orthopaedics and Spine Surgery, Ganga Hospital, Coimbatore, Tamil Nadu, India. sr@gangahospital.com
authors.forename: S
authors.initials: S
authors.lastname: Rajasekaran
authors.forename: Vijay
authors.initials: V
authors.lastname: Kamath
authors.forename: Ajoy P
authors.initials: AP
authors.lastname: Shetty
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007432:Intraoperative Period; D008297:Male; D019060:Minimally Invasive Surgical Procedures; D038361:Neuronavigation / Q000295:instrumentation*; D019637:Orthopedic Procedures / Q000295:instrumentation* / Q000379:methods; D010017:Osteoma, Osteoid / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D011446:Prospective Studies; D015641:Radiography, Interventional; D013125:Spinal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome