Biomechanical evaluation of posterior lumbar dynamic stabilization: An in vitro comparison between Universal Clamp and Wallis systems

Brice Ilharreborde, Miranda N. Shaw, Lawrence J. Berglund, Kristin D. Zhao, Ralph E. Gay, Kai Nan An

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

Treatment of chronic low back pain due to degenerative lumbar spine conditions often involves fusion of the symptomatic level. A known risk of this procedure is accelerated adjacent level degeneration. Motion preservation devices have been designed to provide stabilization to the symptomatic motion segment while preserving some physiologic motion. The aim of this study was to compare the changes in relative range of motion caused as a result of application of two non-fusion, dynamic stabilization devices: the Universal Clamp (UC) and the Wallis device. Nine fresh, frozen human lumbar spines (L1-Sacrum) were tested in flexion-extension, lateral bending, and axial rotation with a custom spine simulator. Specimens were tested in four conditions: (1) intact, (2) the Universal Clamp implanted at L3-4 (UC), (3) the UC with a transverse rod added (UCTR), and (4) the Wallis device implanted at L3-4. Total range of motion at 7.5 N-m was determined for each device and compared to intact condition. The UC device (with or without a transverse rod) restricted motion in all planes more than the Wallis. The greatest restriction was observed in flexion. The neutral position of the L3-4 motion segment shifted toward extension with the UC and UCTR. Motion at the adjacent levels remained similar to that observed in the intact spine for all three constructs. These results suggest that the UC device may be an appropriate dynamic stabilization device for degenerative lumbar disorders.

Original languageEnglish (US)
Pages (from-to)289-296
Number of pages8
JournalEuropean Spine Journal
Volume20
Issue number2
DOIs
StatePublished - Feb 1 2011

Keywords

  • Biomechanics
  • Posterior dynamic stabilization
  • Range of motion
  • Universal Clamp
  • Wallis

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine

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