title: Anterior lumbar interbody fusion with integrated fixation and adjunctive posterior stabilization: A comparative biomechanical analysis.
abstract: BACKGROUND
  Interbody fusion cages with integrated fixation components have become of interest due to their ability to provide enhanced post-operative stability and mitigate device migration. A recently approved anterior lumbar interbody fusion cage with integrated fixation anchors has yet to be compared in vitro to a standard polyetheretherketone cage when used in combination with an interspinous process clamp.
  
  
  METHODS
  Twelve human cadaveric lumbar segments were implanted at L4-L5 with a Solus interbody cage (n=6) or standard polyetheretherketone cage (n=6) following Intact testing and discectomy. Each cage was subsequently evaluated in all primary modes of loading after supplementation with the following posterior constructs: interspinous process clamp, bilateral transfacet screws, unilateral transfacet screw with contralateral pedicle screws, and bilateral pedicle screws. Range of motion results were normalized to Intact, and a two-way mixed analysis of variance was utilized to detect statistical differences.
  
  
  RESULTS
  The Solus cage in combination with all posterior constructs provided significant fixation compared to Intact in all loading conditions. The polyetheretherketone cage also provided significant fixation when combined with all screw based treatments, however when used with the interspinous process clamp a significant reduction was not observed in lateral bending or axial torsion.
  
  
  CONCLUSIONS
  Interbody cages with integrated fixation components enhance post-operative stability within the intervertebral space, thus affording clinicians the potential to utilize less invasive methods of posterior stabilization when seeking circumferential fusion. Interspinous process clamps, in particular, may reduce peri-operative and post-operative comorbidities compared to screw based constructs. Further study is necessary to corroborate their effectiveness in vivo.
authors.affiliation: Department of Neurosurgery, Allegheny General Hospital, 420 East North Avenue, Suite 302, Pittsburgh, PA, 15212, USA. Electronic address: myeager@wpahs.org.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Yeager
authors.affiliation: Department of Neurosurgery, Allegheny General Hospital, 420 East North Avenue, Suite 302, Pittsburgh, PA, 15212, USA. Electronic address: ddupre@wpahs.org.
authors.forename: Derrick A
authors.initials: DA
authors.lastname: Dupre
authors.affiliation: Department of Neurosurgery, Allegheny General Hospital, 420 East North Avenue, Suite 302, Pittsburgh, PA, 15212, USA. Electronic address: dcook1@wpahs.org.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Cook
authors.affiliation: Department of Neurosurgery, Allegheny General Hospital, 420 East North Avenue, Suite 302, Pittsburgh, PA, 15212, USA; Department of Neurosurgery, Drexel University College of Medicine, 420 East North Avenue, Suite 302, Pittsburgh, PA, 15212, USA. Electronic address: moh@wpahs.org.
authors.forename: Michael Y
authors.initials: MY
authors.lastname: Oh
authors.affiliation: Department of Orthopaedic Surgery, Allegheny General Hospital, 1307 Federal Street, Pittsburgh, PA, 15212, USA; Department of Orthopaedic Surgery, Drexel University College of Medicine, 1307 Federal Street, Pittsburgh, PA, 15212, USA. Electronic address: daltman@wpahs.org.
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Altman
authors.affiliation: Department of Neurosurgery, Allegheny General Hospital, 420 East North Avenue, Suite 302, Pittsburgh, PA, 15212, USA; Department of Neurosurgery, Drexel University College of Medicine, 420 East North Avenue, Suite 302, Pittsburgh, PA, 15212, USA. Electronic address: boylecheng@yahoo.com.
authors.forename: Boyle C
authors.initials: BC
authors.lastname: Cheng
mesh_terms: D000368:Aged; D001577:Benzophenones; D001696:Biomechanical Phenomena; D002102:Cadaver; D017586:Diskectomy / Q000295:instrumentation; D006801:Humans; D016268:Internal Fixators; D007596:Joints / Q000601:surgery; D007659:Ketones; D008159:Lumbar Vertebrae / Q000601:surgery*; D008161:Lumbosacral Region; D008875:Middle Aged; D065289:Pedicle Screws; D011092:Polyethylene Glycols; D011108:Polymers; D016059:Range of Motion, Articular; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods*
chemical_list: D001577:Benzophenones; D007659:Ketones; D011108:Polymers; C063834:polyetheretherketone; D011092:Polyethylene Glycols
keywords: Anterior lumbar interbody fusion; Circumferential fusion; Integrated fixation; Interspinous process clamp; Lumbar spine