Effect of an Intervertebral Disk Spacer on Stiffness After Monocortical Screw/Polymethylmethacrylate Fixation in Simulated and Cadaveric Canine Cervical Vertebral Columns. Issue 8 (11th February 2014)

• Record Type: Journal Article
• Authors: Hettlich, Bianca F.; Allen, Matthew J.; Glucksman, Gabriela S.; Fosgate, Geoffrey T.; Litsky, Alan S.
• Is Part Of: Veterinary surgery. Volume 43:Issue 8(2014)
• Page Start: 988
• Page End: 994
• Publication Date: 2014-02-11
• Subjects: Veterinary surgery -- Periodicals; Veterinary Medicine -- Periodicals; Surgery -- Periodicals; Societies, Medical -- Periodicals; 636.0897
• DOI: 10.1111/j.1532-950X.2014.12165.x
• Languages: English
• ISSNs: 0161-3499

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="vsu12165-sec-0001" sec-type="section"> <title>Objective</title> <p>To determine the biomechanical effect of an intervertebral spacer on construct stiffness in a PVC model and cadaveric canine cervical vertebral columns stabilized with monocortical screws/polymethylmethacrylate (PMMA).</p> </sec> <sec id="vsu12165-sec-0002" sec-type="section"> <title>Study Design</title> <p>Biomechanical study.</p> </sec> <sec id="vsu12165-sec-0003" sec-type="section"> <title>Sample Population</title> <p>PVC pipe; cadaveric canine vertebral columns.</p> </sec> <sec id="vsu12165-sec-0004" sec-type="section"> <title>Methods</title> <p>PVC model—PVC pipe was used to create a gap model mimicking vertebral endplate orientation and disk space width of large‐breed canine cervical vertebrae; 6 models had a 4‐mm gap with no spacer (PVC group 1); 6 had a PVC pipe ring spacer filling the gap (PCV group 2). Animals—large breed cadaveric canine cervical vertebral columns (C2–C7) from skeletally mature dogs without (cadaveric group 1, n = 6, historical data) and with an intervertebral disk spacer (cadaveric group 2, n = 6) were used. All PVC models and cadaver specimens were instrumented with monocortical titanium screws/PMMA. Stiffness of the 2 PVC groups was compared in extension, flexion, and lateral bending using non‐destructive 4‐point bend testing. Stiffness testing in all 3 directions was performed of the unaltered C4–C5 vertebral motion unit in cadaveric spines and repeated after placement of an intervertebral cortical allograft ring and instrumentation. Data were compared using a linear mixed model approach that also incorporated data from previously tested spines with the same screw/PMMA construct but without disk spacer (cadaveric group 1).</p> </sec> <sec id="vsu12165-sec-0005" sec-type="section"> <title>Results</title> <p>Addition of a spacer increased construct stiffness in both the PVC model (<italic>P</italic> < .001) and cadaveric vertebral columns (<italic>P</italic> < .001) compared to fixation without a spacer.</p> </sec> <sec id="vsu12165-sec-0006" sec-type="section"> <title>Conclusions</title> <p>Addition of an intervertebral spacer significantly increased construct stiffness of monocortical screw/PMMA fixation.</p> </sec> </abstract>