title: A comparative biomechanical study of a novel integrated plate spacer for stabilization of cervical spine: an in vitro human cadaveric model.
abstract: BACKGROUND
  Integrated plate-spacer may provide adequate construct stability while potentially lowering operative time, decreasing complications, and providing less mechanical obstruction. The purpose of the current study was to compare the biomechanical stability of an anatomically profiled 2-screw integrated plate-spacer to a traditional spacer only and to a spacer and anterior cervical plate construct. In addition, the biomechanical stability of 2-screw integrated plate-spacer was compared to a commercially available 4-screw integrated plate-spacer.
  
  
  METHODS
  Two groups, each of nine cervical cadaver spines (C2-C7), were tested under pure moments of 1.5Nm. Range of motion was recorded at C5-C6 in all loading conditions (flexion, extension, lateral bending, and axial rotation) for the following constructs: 1) Intact; 2) 2-screw or 4-screw integrated plate-spacer; 3) spacer and anterior cervical plate; and 4) spacer only.
  
  
  RESULTS
  All fusion constructs significantly reduced motion compared to the intact condition. Within the instrumented constructs, spacer and anterior cervical plate, 2-screw and 4-screw integrated plate-spacer resulted in reduced motion compared to the spacer only construct. No significant differences were found in motion between any of the instrumented conditions in any of the loading conditions.
  
  
  CONCLUSIONS
  The application of integrated plate-spacer for anterior cervical discectomy and fusion is based on several factors including surgical ease-of-use, biomechanical characteristics, and surgeon preference. The study suggests that integrated plate-spacer provide biomechanical stability comparable to traditional spacer and plate constructs in the cervical spine. Clinical studies on integrated plate spacer devices are necessary to understand the performance of these devices in vivo.
authors.affiliation: Orthopaedic and Spine Specialists, 1855 Powder Mill Road, York, PA 17402, USA. kmajid@orthospinesp.com
authors.forename: Kamran
authors.initials: K
authors.lastname: Majid
authors.forename: Suresh
authors.initials: S
authors.lastname: Chinthakunta
authors.forename: Aditya
authors.initials: A
authors.lastname: Muzumdar
authors.forename: Saif
authors.initials: S
authors.lastname: Khalil
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D002102:Cadaver; D002574:Cervical Vertebrae / Q000601:surgery*; D004867:Equipment Design; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D016268:Internal Fixators; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular; D013123:Spinal Fusion / Q000379:methods; D013314:Stress, Mechanical