Highlights
- •Sacral bicortical screw fixation is commonly used for strength and stability.
- •This study tested a new, multicortical screw fixation technique.
- •Fresh-frozen sacrums were used to compare bicortical and multicortical techniques.
- •Multicortical screw fixation resulted in more strength, stability and load bearing.
Abstract
Background
Bicortical screw fixation is an established technique to increase screw strength in
vertebral bodies, although it is associated with several complications, for example
screw-loosening. Cement augmentation can increase stability of screw-fixation but
can also cause various complications, such as cement-leakage or cement embolism. In
this study, we tested a new, multicortical screw fixation technique in the sacrum.
Methods
Four fresh-frozen sacrums were used. In group 1, standard screw insertion, with sagittal
parallel and axial convergent screw-drive was performed. In group 2, the screw-drive
of the first screw was similar to the screw-drive in group 1. In addition, a second
screw was inserted descending into the intended hole in the head of the screw and
at a stable angle. Therefore, the screws of the multiloc humerus nail-system (Synthes)
were used. The specimens were connected to a testing-machine and underwent cyclic
axial loading with an increase in the load after each completed stage.
Findings
Multicortical screw fixation leads to a significant increase in the number of completed
cycles and a significantly increased load until failure.
Interpretation
Multicortical screw fixation in the sacrum offers a stronger attachment of the screws.
In the future, multicortical implants, which fulfil the criteria demanded in spine
surgery, can offer higher stability and may decrease the loosening rates of the implanted
screws.
Keywords
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References
- A biomechanical study of anterior thoracolumbar screw fixation.Spine. 1998; 23: 1829-1831
- Revision of cannulated and perforated cement-augmented pedicle screws: a biomechanical study in human cadavers.Spine. 2010; 35: E932-E939
- Application of cement on strategic vertebrae in the treatment of the osteoporotic spine.Spine J. 2017; 17: 328-337
Lehman Jr RA, Kuklo TR, Belmont Jr PJ, Andersen RC, Polly Jr DW. Advantage of pedicle screw fixation directed into the apex of the sacral promontory over bicortical fixation: a biomechanical analysis. Spine. 2002;27(8):806–11
- Management of symptomatic lumbar degenerative disk disease.J. Am. Acad. Orthop. Surg. 2009; 17 (Feb 1): 102-111
- Pedicular anatomy of the first sacral segment in transitional variations of the lumbo-sacral junction.Spine. 2011; 36: E1187-E1192
- Biomechanical analysis of lumbosacral fixation.Spine. 1992; 17: S235-S243
- Use of pedicle percutaneous cemented screws in the management of patients with poor bone stock.Neuro-Chirurgie. 2016; 62: 306-311
- Revision pedicle screws: bigger, longer shims-what is best?.Spine. 1998; 23: 1374-1379
- Loads on internal spinal fixation devices. Die Belastung des Wirbel-Fixateur-interne.Orthopade. 1999; 28: 451-457
- Timing of PMMA cement application for pedicle screw augmentation affects screw anchorage.Eur. Spine J. 2017; 26: 2883-2890
- Designs and techniques that improve the pullout strength of pedicle screws in osteoporotic vertebrae: current status.Biomed. Res. Int. 2014; 2014
- Embalmed and fresh frozen human bones in orthopedic cadaveric studies: which bone is authentic and feasible? A mechanical study.Acta Orthop. 2012; 83: 543-547
- Sacral bone mass distribution assessed by averaged three-dimensional CT models: implications for pathogenesis and treatment of fragility fractures of the sacrum.Joint Bone Joint Surg. Am. 2016; 98: 584-590
- Anatomic and technical considerations of pedicle screw fixation.Clin. Orthop. Relat. Res. 1992; 34-46
- Effect of the degree of osteoporosis on the biomechanical anchoring strength of the sacral pedicle screws: an in vitro comparison between unaugmented bicortical screws and polymethylmethacrylate augmented unicortical screws.Spine. 2010; 35: E925-E931
- A biomechanical study of intrapeduncular screw fixation in the lumbosacral spine.Clin. Orthop. Relat. Res. 1986; : 99-112
Article Info
Publication History
Published online: April 15, 2019
Accepted:
April 12,
2019
Received:
January 23,
2019
Footnotes
☆Declarations of interest: None.
Identification
Copyright
© 2019 Elsevier Ltd. All rights reserved.
