Ultra-high-molecular-weight polyethylene sublaminar tape as semirigid fixation or pedicle screw augmentation to prevent failure in long-segment spine surgery: an ex vivo biomechanical study

R.J.P. Doodkorte*, R. Belda, A.K. Roth, B. van Rietbergen, J.J. Arts, L.M.A. Lataster, L.W. van Rhijn, P.C. Willems

*Corresponding author for this work

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Abstract

OBJECTIVE Complications after adult spinal deformity surgery are common, with implant-related complications occurring in up to 27.8% of cases. Sublaminar wire fixation strength is less affected by decreasing trabecular bone density in comparison to pedicle screw (PS) fixation due to the predominant cortical bone composition of the lamina. Sublaminar fixation may thus aid in decreasing implant-related complications. The goal of this study was to compare fixation characteristics of titanium sublaminar cables (SCs), ultra-high-molecular-weight polyethylene (UHMWPE) tape, PSs, and PSs augmented with UHMWPE tape in an ex vivo flexion-bending setup.METHODS Thirty-six human cadaver vertebrae were stratified into 4 different fixation groups: UHMWPE sublaminar tape (ST), PS, metal SC, and PS augmented with ST (PS + ST). Individual vertebrae were embedded in resin, and a flexion-bending moment was applied that closely resembles the in vivo loading pattern at transitional levels of spinal instrumentation.RESULTS The failure strength of PS + ST (4522 +/- 2314 N) was significantly higher compared to the SC (2931 +/- 751 N) and PS (2678 +/- 827 N) groups, which had p values of 0.028 and 0.015, respectively (all values expressed as the mean +/- SD). Construct stiffness was significantly higher for the PS groups compared to the stand-alone sublaminar wiring groups (p = 0.020). In contrast to SC, ST did not show any case of cortical breach.CONCLUSIONS The higher failure strength of PS + ST compared to PS indicates that PS augmentation with ST may be an effective measure to reduce the incidence of screw pullout, even in osteoporotic vertebrae. Moreover, the lower stiffness of sublaminar fixation techniques and the absence of damage to the cortices in the ST group suggest that ST as a stand-alone fixation technique in adult spinal deformity surgery may also be clinically feasible and offer clinical benefits.
Original languageEnglish
Pages (from-to)236-244
Number of pages9
JournalJournal of Neurosurgery: Spine
Volume34
Issue number2
DOIs
Publication statusPublished - 1 Feb 2021

Keywords

  • biomechanics
  • constructs
  • density
  • hooks
  • instrumentation
  • pedicle screws
  • pullout strength
  • rates
  • scoliosis
  • spinal deformity
  • sublaminar wires
  • surgical technique
  • INSTRUMENTATION
  • CONSTRUCTS
  • HOOKS
  • SCOLIOSIS
  • DENSITY
  • RATES
  • PULLOUT STRENGTH

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