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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
Pedicle screw surface coatings improve fixation in nonfusion spinal constructs
Vidyadhar V Upasani1, Christine L Farnsworth, Tucker Tomlinson
1Department of Orthopedic Surgery, University of California San Diego, San Diego, CA, USA.
Spine
|February 3, 2009
Summary
Hydroxyapatite (HA) and titanium plasma spray (TPS) coatings significantly improve pedicle screw fixation in the spine. These enhanced coatings reduce screw loosening compared to uncoated screws, potentially improving outcomes in spinal instrumentation.
Area of Science:
- Orthopedic Surgery
- Biomaterials Science
- Spinal Instrumentation
Background:
- Transpedicular screw fixation is standard for thoracolumbar conditions.
- Pedicle screw loosening is a concern, particularly in challenging cases or with low bone density.
Purpose of the Study:
- To compare the bone-screw interface strength of standard uncoated pedicle screws with those treated with hydroxyapatite (HA), titanium plasma spray (TPS), and a composite HA-TPS coating.
Main Methods:
- Biomechanical and histologic analysis of 4 types of titanium monoaxial pedicle screws (uncoated, HA-only, TPS-only, HA-TPS composite) in porcine spines.
- Torsional screw extraction and nondecalcified histologic analysis after a 3-month survival period.
Main Results:
- All coated screws showed increased peak torque (fixation) at 3 months, while uncoated screws decreased significantly.
- HA-only and HA-TPS composite screws demonstrated improved osseointegration histologically.
- TPS-only screws showed a higher incidence of near-zero peak torque compared to HA-containing screws.
Conclusions:
- Pedicle screw coatings (TPS for mechanical interlocking, HA for osteoblast bonding) enhance screw fixation.
- HA-containing coatings may decrease screw loosening and improve outcomes in nonfusion spinal procedures.
