Journal article
Enhancing Pedicle Screw Fixation in the Lumbar Spine Using Allograft Bone Plug Interference Fixation
Journal of spinal disorders & techniques, Vol.27(3), pp.E81-E87
05/01/2014
DOI: 10.1097/BSD.0b013e318290fc84
PMID: 23563347
Abstract
Study Design:A within-subjects controlled laboratory study.Objective:To examine a biological alternative to cement augmentation for pedicle screw fixation comparing bilateral axial pullout tests of augmented and nonaugmented (controls) pedicle screws.Summary of Background Data:Fixation in the osteoporotic spine remains a difficult challenge with failure by loosening or backout. Pedicle screw augmentation has been attempted using polymethylmethacrylate and bioabsorbable calcium cements; however, the potential for extravasation and embolization of cement are becoming increasingly concerning and merit the search for alternative methods to improve screw-anchoring strength.Methods:Twenty-four (24) fresh human lumbar vertebrae were tested to compare the pullout strength of augmented and nonaugmented pedicle screws. Two different augmentation strategies were employed using allograft bone plugs (ABPs) and evaluated using 12 specimens per group. Bone mineral density of each specimen was obtained using dual-energy x-ray absorptiometry. The augmented versus nonaugmented pedicle was randomized for each vertebra, and bilateral testing enabled paired statistical analyses. Axial pullout tests were performed using an materials testing system servohydraulic test system, and peak force, failure displacement, and stiffness was obtained for each test and correlated with bone mineral density.Results:Augmentation using 6-mm-diameter ABPs with 6.25-mm-diameter pedicle screws resulted in statistically weaker average pullout strength (775455 N) than the nonaugmented controls (1233 +/- 826 N). When using smaller (5 mm diameter) AGPs with the same diameter screws, there was no statistical difference between average pullout strength for the augmented pedicle screws (1772 +/- 652 N) and the nonaugmented screws (1780 +/- 575 N).Conclusions:Preliminary study of pedicle screw augmentation using cannulated ABPs showed no improvement of fixation with pedicles in the spine. This was even true in osteoporotic specimens, where augmentation would seem to be of considerable benefit.
Details
- Title: Subtitle
- Enhancing Pedicle Screw Fixation in the Lumbar Spine Using Allograft Bone Plug Interference Fixation
- Creators
- Bopha Chrea - University of WashingtonHarsha Malempati - University of WashingtonJeffrey R. Campbell - University of WashingtonSonja Khan - University of WashingtonRandal P. Ching - University of WashingtonMichael J. Lee - University of Washington
- Resource Type
- Journal article
- Publication Details
- Journal of spinal disorders & techniques, Vol.27(3), pp.E81-E87
- Publisher
- Lippincott Williams & Wilkins
- DOI
- 10.1097/BSD.0b013e318290fc84
- PMID
- 23563347
- ISSN
- 1536-0652
- eISSN
- 1539-2465
- Number of pages
- 7
- Grant note
- AOSpine International (Clinical Priority Program-Fracture Fixation in Osteoporotic Bone)
- Language
- English
- Date published
- 05/01/2014
- Academic Unit
- Orthopedics and Rehabilitation
- Record Identifier
- 9984459622002771
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