Biomechanical in vitro comparison between anterior column realignment and pedicle subtraction osteotomy for severe sagittal imbalance correction

Luigi La Barbera, Hans Joachim Wilke, Christian Liebsch, Tomaso Villa, Andrea Luca, Fabio Galbusera, Marco Brayda-Bruno

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: To investigate the biomechanical effects of anterior column realignment (ACR) and pedicle subtraction osteotomy (PSO) on local lordosis correction, primary stability and rod strains. Methods: Seven cadaveric spine segments (T12–S1) underwent ACR at L1–L2. A stand-alone hyperlordotic cage was initially tested and then supplemented with posterior bilateral fixation. The same specimens already underwent a PSO at L4 stabilized by two rods, a supplemental central rod (three rods) and accessory rods (four rods) with and without adjacent interbody cages (La Barbera in Eur Spine J 27(9):2357–2366, 2018). In vitro flexibility tests were performed under pure moments in flexion/extension (FE), lateral bending (LB) and axial rotation (AR) to determine the range of motion (RoM), while measuring the rod strains with strain gauge rosettes. Results: Local lordosis correction with ACR (24.7° ± 3.7°) and PSO (25.1° ± 3.9°) was similar. Bilateral fixation significantly reduced the RoM (FE: 31%, LB: 2%, AR: 18%), providing a stability consistent with PSO constructs (p > 0.05); however, it demonstrates significantly higher rod strains compared to PSO constructs with lateral accessory rods and interbody cages in FE and AR (p < 0.05), while being comparable in FE or slightly higher in AR compared to PSO constructs with two and three rods. Conclusion: Bilateral posterior fixation is highly recommended following ACR to provide adequate primary stability. However, primary rod strains in ACR were found comparable or higher than weak PSO construct associated with frequent rod failure; therefore, caution is recommended. Graphic abstract: These slides can be retrieved under Electronic Supplementary Material.[Figure not available: see fulltext.].

Original languageEnglish
Pages (from-to)36-44
Number of pages9
JournalEuropean Spine Journal
Volume29
Issue number1
DOIs
Publication statusPublished - 2020

Keywords

  • Anterior column release
  • Biomechanics
  • In vitro study
  • Pedicle subtraction osteotomy
  • Primary stability
  • Revision surgery
  • Rod breakage
  • Spine
  • Strain gauge

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine

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