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Updated: Jun 13, 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
[Biomechanics of interspinous spacers]
H-J Wilke1, J Drumm, K Häussler
1Institut für Unfallchirurgische Forschung und Biomechanik, Zentrum für muskuloskelettale Forschung, Universitätsklinikum Ulm, Helmholtzstrasse 14, 89081, Ulm, Deutschland. hans-joachim.wilke@uni-ulm.de
Interspinous spacers effectively stabilize the lumbar spine after decompression, limiting extension while preserving motion in other planes. These devices offer comparable biomechanical effects across different types, aiding treatment for spinal stenosis and arthritis.
Area of Science:
- Spinal Biomechanics
- Orthopedic Surgery
- Medical Device Engineering
Background:
- Interspinous spacers are utilized for treating lumbar spinal stenosis and facet joint arthritis.
- Key goals include unloading facet joints, restoring foraminal height, and enhancing stability while allowing motion.
Purpose of the Study:
- To compare the biomechanical effects of four distinct interspinous implants: Coflex, Wallis, DIAM, and X-STOP.
- Evaluation focused on primary stability, intradiscal pressure, and stability following cyclic loading.
Main Methods:
- In vitro biomechanical testing of 24 human lumbar spine specimens.
- Specimens were tested in intact, decompressed (hemifacetectomy), and post-implantation states under various loading conditions.
Main Results:
- All four implants demonstrated similar biomechanical effects, significantly restricting extension compared to the intact state.
- Motion in flexion, lateral bending, and axial rotation remained comparable to the decompressed state.
- Intradiscal pressure post-implantation was similar to intact states in most motions but reduced in extension.
- Cyclic loading (50,000 cycles) minimally increased range of motion, with extension remaining below intact levels.
Conclusions:
- Interspinous implants provide significant stability, particularly by limiting extension, after spinal decompression.
- The tested implants offer comparable biomechanical performance, effectively managing instability without compromising other motion planes excessively.
