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Updated: Mar 22, 2026
An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model
Published on: May 31, 2017
Spinal shape modulation in a porcine model by a highly flexible and extendable non-fusion implant system
Martijn Wessels1, Edsko E G Hekman2, Moyo C Kruyt3
1Laboratory of Biomechanical Engineering, Faculty of Engineering Technology, University of Twente, PO Box 217, 7500 AE, Enschede, The Netherlands. m.wessels@utwente.nl.
Purpose:
In vivo evaluation of scoliosis treatment using a novel approach in which two posterior implants are implanted: XSLAT (eXtendable implant correcting Scoliosis in LAT bending) and XSTOR (eXtendable implant correcting Scoliosis in TORsion). The highly flexible and extendable implants use only small, but continuous lateral forces (XSLAT) and torques (XSTOR), thereby allowing growth and preventing fusion.
Methods:
Since (idiopathic) scoliosis does not occur spontaneously in animals, the device was used to induce a spinal deformity rather than correct it. Six of each implants were tested for their ability to induce scoliotic deformations in 12 growing pigs. Each implant spanned six segments and was attached to three vertebrae using sliding anchors. Radiological and histological assessments were done throughout the 8-week study.
Results:
In all animals, the intended deformation was accomplished. Average Cobb angles were 19° for XSLAT and 6° for XSTOR. Average apical spinal torsion was 0° for XSLAT and 9° for XSTOR. All instrumented segments remained mobile and showed 20 % growth. Moderate degeneration of the facet joints was observed and some debris was found in the surrounding tissue.
Conclusions:
The approach accomplished the intended spinal deformation while allowing growth and preventing fusion.
