What question did this study set out to answer?

To evaluate the mechanical stabilizing properties of threaded interbody inserts for lumbar fusion and identify factors governing motion segment stability.

November 1, 1995Spine

Biomechanical Properties of Threaded Inserts for Lumbar Interbody Spinal Fusion

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Authors

ATAllan F. TencerUniversity of Washington DHDavid HamptonUniversity of Chicago SESharon EddyUniversity of Washington

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Implication

Biomechanical cadaveric study demonstrates enhanced spinal stability and reduced laxity using threaded interbody inserts, indicating soft-tissue tension is critical for fusion segment stiffness.

Key Points

To evaluate the mechanical stabilizing properties of threaded interbody inserts for lumbar fusion and identify factors governing motion segment stability.
Tested calf and human cadaveric lumbar motion segments under multi-directional loading (flexion, extension, lateral bending, and torsion) combined with axial compression.
Quantified stiffness and neutral zone laxity across varying cage insertion vectors, implant counts, device geometries (cylindrical vs. conical), and supplemental posterior pedicle screw plate fixations.
Determined the maximum axial compressive load-bearing threshold of threaded inserts embedded within calf vertebral bone.
Insert orientation (lateral, posterolateral, or posterior) did not significantly alter stiffness except in torsion, where posterior entry damaged facets or laminae, whereas two posterior inserts significantly reduced flexion and lateral bending laxity.
Conical inserts placed anteriorly distracted intervertebral soft tissues to decrease laxity, while supplemental posterior plates significantly increased flexion and lateral bending stiffness while decreasing laxity across flexion, extension, and lateral bending.
Threaded inserts supported a mean maximum compressive load of 2998 N (SD = 980 N), with structural mechanical failure occurring within the supporting host bone rather than the implant.

Cite This Study

Tencer et al. (1995) studied this question.

synapsesocial.com/papers/6a81902ca2b9faa7beb6bd94 https://doi.org/10.1097/00007632-199511001-00007

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Implication

Biomechanical cadaveric study demonstrates enhanced spinal stability and reduced laxity using threaded interbody inserts, indicating soft-tissue tension is critical for fusion segment stiffness.

Biomechanical Properties of Threaded Inserts for Lumbar Interbody Spinal Fusion

Discussion

Member takes

Implication

Key Points

Cite This Study

Biomechanical Properties of Threaded Inserts for Lumbar Interbody Spinal Fusion

Discussion

Member takes

Implication

Key Points

Cite This Study

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