title: Navigated placement of iliac bolts: description of a new technique.
abstract: BACKGROUND
  Image navigation has improved the safety and ability to perform complex spinal procedures where visibility is not optimal or anatomic deformity is present. Numerous published studies are available demonstrating its effectiveness in improved pedicle screw placement in complex multiplanar deformities. Studies have also demonstrated image navigation technology versatility; however, stabilization of the lumbopelvic junction with navigated iliac bolt fixation has not been reported.
  
  
  OBJECTIVE
  To describe an innovative versatile application of image navigation technology in spine surgery. We examine the safety, accuracy, and effectiveness of navigated iliac bolt placement while minimizing challenges associated with current techniques.
  
  
  METHODS
  Case series.
  
  
  METHODS
  Five patients requiring lumbopelvic fixation for multiple indications, including lumbosacral pseudoarthrosis, complex sacral fracture patterns, compromised revision sacral fixation, and as an adjunct to degenerative deformity with multilevel fusion, underwent navigated iliac bolt placement.
  
  
  METHODS
  Accurate placement was verified using intraoperative computed tomography (CT) imaging using O-ARM (Medtronic, Inc.) after placement.
  
  
  METHODS
  Five patients requiring lumbopelvic fixation have undergone navigated iliac bolt placement using Medtronic Stealth Station Treon in conjunction with the O-ARM (Medtronic, Inc.). A right percutaneous posterior superior iliac spine (PSIS) reference frame was placed at the superior lateral margin of the PSIS, and bilateral iliac bolts were placed via navigation using both the anatomic and traditional surgical techniques. Both techniques were performed without direct notch palpation and minimal soft-tissue exposure. Postplacement intraoperative CT imaging was obtained to confirm position and trajectory of the bolts using O-ARM (Medtronic, Inc.).
  
  
  RESULTS
  Ten iliac bolts were successfully placed in five patients. Intraoperative CT demonstrated ideal iliac screw bone placement projecting within 2 cm over sciatic notch, between pelvic tables. With image navigation, both anatomic and traditional iliac bolt placement techniques were performed with less surgical exposure, no radiation exposure, and complete accuracy using image navigation techniques with a percutaneous reference frame. The percutaneous reference frame placed in the superior lateral PSIS did not cause any interference with our navigated trajectory or bolt.
  
  
  CONCLUSIONS
  Image-navigated iliac fixation allows for safe and accurate placement of bilateral iliac bolts without PSIS percutaneous reference frame interference. Image guidance eliminates fluoroscopic radiation exposure and extensive soft-tissue dissection and facilitates both traditional and anatomic iliac bolt placement techniques.
authors.affiliation: Lake Norman Orthopedic Spine Center, 170 Medical Park Rd, Suite 102, Mooresville, NC 28117, USA. bgarrido@yahoo.com
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Garrido
authors.forename: Ken E
authors.initials: KE
authors.lastname: Wood
mesh_terms: D006801:Humans; D007085:Ilium / Q000000981:diagnostic imaging / Q000601:surgery*; D016268:Internal Fixators; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D012447:Sacrum / Q000000981:diagnostic imaging / Q000601:surgery*; D013123:Spinal Fusion / Q000379:methods*; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed