Three-dimensional stabilization provided by the external spinal fixator compared to two internal fixation devices: a biomechanical in vitro flexibility study

Lund, Teija; Nydegger, Thomas; Ráthonyi, Gábor K.; Nolte, Lutz‐Peter; Schlenzka, Dietrich; Oxland, Thomas R.

doi:10.1007/s00586-002-0519-2

Cited by 14 publications

(5 citation statements)

References 22 publications

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“…While non‐union per se, may not strictly correlate to a poor clinical outcome, especially in the short term, stable unions are clearly correlated with superior clinical outcomes (15–17) . Because of this, research in methods to improve spine fusion, whether through biological or mechanical interventions (devices), remains intense (18–20) . Currently, autogenous bone grafting is the gold standard for induction of a spine fusion.…”

Section: Introductionmentioning

confidence: 99%

Combined Bone Morphogenetic Protein-2 and −7 Gene Transfer Enhances Osteoblastic Differentiation and Spine Fusion in a Rodent Model

Zhu

Rawlins

Boachie-Adjei

et al. 2004

Journal of Bone and Mineral Research

166

132

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To enhance the osteogenic activity of BMP, combination BMP2 and BMP7 gene transfer was performed. This approach led to a significant increase in osteoblastic differentiation of mesenchymal precursors compared with single BMP gene transfer in vitro. When tested in 78 rats, combination gene transfer enhanced mechanically stable spine fusion and bone formation rate versus single BMP gene transfer.Introduction: Although clinical bone morphogenetic protein (BMP) therapy is effective, required doses are very high. Previous studies have suggested that the co-expression of two different BMP genes can result in the production of heterodimeric BMPs that may be more potent than homodimers. In this study, combined BMP2 and BMP7 gene transfer was performed to test whether this approach improves osteoblastic differentiation and bone formation compared with single BMP gene transfer. Materials and Methods: A producer cell (A549) was co-transfected with adenovirus vectors encoding BMP2 (AdBMP2) and BMP7 (AdBMP7) or, as controls, each vector alone, AdNull (with no transgene) or no virus. Supernatants were compared for their ability to stimulate osteoblastic differentiation of C2C12 myoblasts and MC3T3-E1 pre-osteoblasts. In a rat posterolateral spine fusion model, co-administration of AdBMP2 and AdBMP7 was compared with treatment with each vector alone, AdNull or no virus in 78 rats. The spines were assessed 8 weeks after surgery for radiographic and mechanical fusion, bone formation, and mineralization. Results: BMP2 and BMP7 were co-precipitated from supernatants of cells co-transfected with AdBMP2 and AdBMP7, indicating the presence of BMP2/7 heterodimer. Supernatants of co-transfected cells containing relatively low doses (7-140 ng/ml) of BMPs induced osteocalcin expression and alkaline phosphatase activity in both C2C12 and MC3T3-E1 cells, that were up to 6-and 40-fold higher, respectively, than levels induced by maximal doses (200 -1000 ng/ml) of either BMP2 or BMP7 alone. In the spine fusion model, co-administration of AdBMP2 and AdBMP7 resulted in a significantly greater number of mechanically stable fusions and also 2-fold higher mineralization rate and bone volume in the fusion mass versus single BMP gene transfer (p Ͻ 0.02, all comparisons). Conclusion: Combined BMP2 and BMP7 gene transfer is significantly more effective in inducing osteoblastic differentiation and spine fusion than individual BMP gene transfer.

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Section: Introductionmentioning

confidence: 99%

Combined Bone Morphogenetic Protein-2 and −7 Gene Transfer Enhances Osteoblastic Differentiation and Spine Fusion in a Rodent Model

Zhu

Rawlins

Boachie-Adjei

et al. 2004

Journal of Bone and Mineral Research

166

132

View full text Add to dashboard Cite

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“…The authors of biomechanical studies have shown that lumbar FSF is biomechanically equivalent to PSF; 10,22 however, the efficacy of FSF has not been previously defined in thoracic spine. In the present study, we demonstrated that transfacet pedicle screw fixation is biomechanically applicable in the thoracic region and that it might offer an alternative to PSF for posterior thoracic fusion.…”

Section: Discussionmentioning

confidence: 97%

Thoracic transfacet pedicle screw fixation: a new instrumentation technique

Akbay

İnceoğlu

Milks

et al. 2005

Journal of Neurosurgery: Spine

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Object. Pedicle screw instrumentation of the thoracic spine remains technically challenging. Transverse process and costotransverse screw fixation techniques have been described as alternatives to pedicle screw fixation (PSF). In this study, the authors introduce thoracic transfacet PSF and compare its experimental biomechanical results with those of standard PSF in short-term cyclic loading in cadaveric thoracic specimens. Methods. Specimens were tested intact for six cycles at compressive loads of 250 N offset by 1 cm along appropriate axes to induce flexion, extension, and left and right lateral bending. The specimens were then fixed with either a pedicle screw/rod construct or transfacet pedicle screws and retested in the same fashion. After this sequence, specimens were loaded until failure in flexion mode at a rate of 5 mm/minute was observed. Both fixation constructs provided significantly greater stiffnesses than that demonstrated when the specimen was intact (p < 0.05, two-way analysis of variance). Additionally, the two constructs were statistically equivalent in terms of stiffness and load-to-failure values (p < 0.05, two-tailed nonpaired t-test). The only difference observed was that the low midthoracic region (T7–9) was biomechanically weaker than the upper midthoracic and lower thoracic areas in flexion after the destabilization and instrumentation-augmented stabilization procedures. Conclusions. In selected thoracic surgical procedures, transfacet PSF may, after analysis of long-term biomechanical data, potentially become a reasonable alternative to conventional PSF.

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“…It is considered a good alternative to pedicle screw fixation. Biomechanical studies have shown that lumbar transfacet pedicle screw is biomechanically equivalent to the pedicle screw [18,19]. Akbay et al [20] used the transfacet pedicle screw in the middle and lower thoracic spine to compare its experimental biomechanical result with that of standard pedicle screw.…”

Section: Discussionmentioning

confidence: 98%

CT evaluation of upper thoracic spine for surgical application of transarticular screw placement

Xie

et al. 2011

Eur Spine J

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Three-dimensional stabilization provided by the external spinal fixator compared to two internal fixation devices: a biomechanical in vitro flexibility study

Cited by 14 publications

References 22 publications

Combined Bone Morphogenetic Protein-2 and −7 Gene Transfer Enhances Osteoblastic Differentiation and Spine Fusion in a Rodent Model

Combined Bone Morphogenetic Protein-2 and −7 Gene Transfer Enhances Osteoblastic Differentiation and Spine Fusion in a Rodent Model

Thoracic transfacet pedicle screw fixation: a new instrumentation technique

CT evaluation of upper thoracic spine for surgical application of transarticular screw placement

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