Biomechanical analysis of anterior versus posterior instrumentation following a thoracolumbar corpectomy

Stephanus V. Viljoen, Nicole A. DeVries Watson, Nicole M. Grosland, James Torner, Brian D. Dalm, Patrick W. Hitchon

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

Object. The objective of this study was to evaluate the biomechanical properties of lateral instrumentation compared with short- and long-segment pedicle screw constructs following an L-1 corpectomy and reconstruction with an expandable cage.

Methods. Eight human cadaveric T10-L4 spines underwent an L-1 corpectomy followed by placement of an expandable cage. The spines then underwent placement of lateral instrumentation consisting of 4 monoaxial screws and 2 rods with 2 cross-connectors, short-segment pedicle screw fixation involving 1 level above and below the corpectomy, and long-segment pedicle screw fixation (2 levels above and below). The order of instrumentation was randomized in the 8 specimens. Testing was conducted for each fixation technique. The spines were tested with a pure moment of 6 Nm in all 6 degrees of freedom (flexion, extension, right and left lateral bending, and right and left axial rotation).

Results. In flexion, extension, and left/right lateral bending, posterior long-segment instrumentation had significantly less motion compared with the intact state. Additionally, posterior long-segment instrumentation was significantly more rigid than short-segment and lateral instrumentation in flexion, extension, and left/right lateral bending. In axial rotation, the posterior long-segment construct as well as lateral instrumentation were not significantly more rigid than the intact state. The posterior long-segment construct was the most rigid in all 6 degrees of freedom.

Conclusions. In the setting of highly unstable fractures requiring anterior reconstruction, and involving all 3 columns, long-segment posterior pedicle screw constructs are the most rigid. (http://thejns.org/doi/abs/10.3171/2014.6.SPINE13751).

Original languageEnglish (US)
Pages (from-to)577-581
Number of pages5
JournalJournal of Neurosurgery: Spine
Volume21
Issue number4
DOIs
StatePublished - Oct 1 2014

Keywords

  • Anterior instrumentation
  • Biomechanics
  • Posterior instrumentation
  • Thoracic
  • Thoracolumbar corpectomy

ASJC Scopus subject areas

  • Clinical Neurology
  • Surgery
  • Neurology
  • Medicine(all)

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