title: The manubrium as an external guide for centralizing anterior cervical plates: technique tips and initial experience.
abstract: METHODS
  Technique tips and retrospective review of prospectively collected data.
  
  
  OBJECTIVE
  To describe a technique for centralizing cervical plates using the center of the manubrium as a primary external guide and its alignment with the mandible as a secondary guide.
  
  
  BACKGROUND
  Proper alignment of cervical plates is desirable to avoid improper placement of screws and possibly altered biomechanical performance. Large body habitus may portend suboptimal exposure, a limited utility of skin surface landmarks for level determination, and may make it difficult to reliably centralize plates in the coronal plane during anterior cervical surgery.
  
  
  METHODS
  We describe a technique that uses the center of the manubrium to determine the midline of the cervical spine and align a line drawn through the manubrium with the center of the mandible to provide a central axis for placing cervical plates along the entire cervical spine. We used anteroposterior fluoroscopy to validate that a line from the middle of the manubrium to the mandible bisected the spinous processes and midline of the vertebral bodies. We prospectively collected data on 39 consecutive patients undergoing anterior cervical discectomy and fusion with cervical plates using this technique.
  
  
  RESULTS
  The mean amount of angulation and translation about a midline axis were 2.24 degrees +/- 1.49 degrees and 1.04 +/- 0.86 mm, respectively. There were no statistical differences among 1-level, 2-level, and 3-level fusions (P > 0.05). The intraobserver correlation coefficient for the measurement technique was R = 0.90 (P = 0.0016).
  
  
  CONCLUSIONS
  We validated that the midline of the cervical spine is in line with a straight bovie cord connecting the midline of the manubrium to the midline of the mandible using anteroposterior fluoroscopy. Using this line, we prospectively centered cervical plates with no significant difference between levels. These data may also serve as a benchmark for assessing cervical plate alignment.
authors.affiliation: The Institute for Minimally Invasive Spine Surgery (iMIS), Palm Beach, FL, USA. kingsleychin@iMISsurgery.com
authors.forename: Kingsley R
authors.initials: KR
authors.lastname: Chin
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Stieber
authors.forename: Samir
authors.initials: S
authors.lastname: Mehta
authors.forename: Jason D
authors.initials: JD
authors.lastname: Cohen
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Auerbach
mesh_terms: D001860:Bone Plates; D002574:Cervical Vertebrae / Q000601:surgery*; D006801:Humans; D016268:Internal Fixators; D008371:Manubrium / Q000601:surgery*; D019919:Prosthesis Implantation / Q000379:methods*; D012189:Retrospective Studies; D016683:Supine Position; D016896:Treatment Outcome