title: Surgical treatment of occipitocervical instability.
abstract: OBJECTIVE
  Instability of the occipitocervical junction can be a challenging surgical problem because of the unique anatomic and biomechanical characteristics of this region. We review the causes of instability and the development of surgical techniques to stabilize the occipitocervical junction.
  
  
  METHODS
  Occipitocervical instrumentation has advanced significantly, and modern modular screw-based constructs allow for rigid short-segment fixation of unstable elements while providing the stability needed to achieve successful fusion in nearly 100% of patients. This article reviews the preoperative planning, the variety of instrumentation and surgical strategies, as well as the postoperative care of these patients.
  
  
  RESULTS
  Current constructs use occipital plates that are rigidly fixed to the thick midline keel of the occipital bone, polyaxial screws that can be placed in many different trajectories, and rods that are bent to approximate the acute occipitocervical angle. These modular constructs provide a variety of methods to achieve fixation in the atlantoaxial complex, including transarticular screws or C1 lateral mass screws in combination with C2 pars, C2 pedicle, or C2 translaminar trajectories.
  
  
  CONCLUSIONS
  Surgical techniques for occipitocervical instrumentation and fusion are technically challenging and require meticulous preoperative planning and a thorough understanding of the regional anatomy, instrumentation, and constructs. Modern screw-based techniques for occipitocervical fusion have established clinical success and demonstrated biomechanical stability, with fusion rates approaching 100%.
authors.affiliation: Department of Neurosurgery, University of Utah, Salt Lake City, Utah 84132, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Finn
authors.forename: Frank S
authors.initials: FS
authors.lastname: Bishop
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Dailey
mesh_terms: D001269:Atlanto-Occipital Joint / Q000503:physiopathology / Q000601:surgery*; D002574:Cervical Vertebrae / Q000601:surgery*; D006801:Humans; D008488:Medical Illustration; D013122:Spinal Diseases / Q000503:physiopathology / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods*