A biomechanical comparison of unilateral and bilateral String-of-Pearls™ locking plates in a canine distal humeral metaphyseal gap model

2014 ◽  
Vol 27 (03) ◽  
pp. 186-191 ◽  
Author(s):  
J. A. Syrcle ◽  
S. Elder ◽  
R. McLaughlin ◽  
R. J. Hurt
Keyword(s):  
Ultimate Strength ◽  
Axial Compression ◽  
Locking Plates ◽  
Gap Model ◽  
Supracondylar Humeral Fractures ◽  
Biomechanical Comparison ◽  
Sop Plate ◽  
String Of Pearls ◽  
Monocortical Screws

SummaryObjective: To compare the in vitro biomechanical performance of two String-of-Pearls (SOP) plate constructs in a canine distal humeral metaphyseal gap model.Methods: Seven pairs of canine cadaveric humeri, including the elbow joints, were prepared. One group consisted of a unilateral medially placed SOP plate with bicortical screws (UNI). The second group consisted of bilateral caudo-medial and caudo-lateral SOP plates applied with monocortical screws (BI). A 2 cm ostectomy was performed immediately proximal to the supratrochlear foramen. Constructs were tested in torsion and axial compression.Results: The UNI constructs had significantly lower stiffness in torsion and axial compression than the BI group. However, UNI constructs had a significantly higher ultimate strength than BI constructs. All UNI constructs failed by bending of the transcondylar screw and SOP plate. All BI constructs failed by axial pullout of the distal most screws.Clinical significance: In stabilizing canine supracondylar humeral fractures as modeled here, both the UNI model and the BI model demonstrated biomechanical advantages. The incorporation of a transcondylar screw through the medial plate appears to be beneficial to construct strength.

Biomechanical Comparison of Two Alternative Tibial Plateau Leveling Osteotomy Plates with the Original Standard in an Axially Loaded Gap Model: An In Vitro Study

2009 ◽  
Vol 38 (1) ◽  
pp. 40-48 ◽  
Author(s):  
PAUL A. KLOC ◽  
MICHAEL P. KOWALESKI ◽  
ALAN S. LITSKY ◽  
NANCY O. BROWN ◽  
KENNETH A. JOHNSON
Keyword(s):  
Tibial Plateau ◽  
In Vitro Study ◽  
Vitro Study ◽  
Gap Model ◽  
Axially Loaded ◽  
Biomechanical Comparison

scholarly journals A biomechanical comparison of 3.5 locking compression plate fixation to 3.5 limited contact dynamic compression plate fixation in a canine cadaveric distal humeral metaphyseal gap model

2009 ◽  
Vol 22 (04) ◽  
pp. 1-8 ◽  
Author(s):  
O. Lanz ◽  
R. McLaughlin ◽  
S. Elder ◽  
S. Werre ◽  
D. Filipowicz
Keyword(s):  
Axial Compression ◽  
Dynamic Testing ◽  
Dynamic Compression ◽  
Plate Fixation ◽  
Locking Compression Plate ◽  
Locking Plates ◽  
Gap Model ◽  
Static Compression ◽  
Dynamic Compression Plate ◽  
Compression Plate

Summary3.5 locking compression plate (LCP) fixation was compared to 3.5 limited contact dynamic compression plate (LC-DCP) fixation in a canine cadaveric, distal humeral metaphyseal gap model. Thirty paired humeri from adult, large breed dogs were separated into equal groups based on testing: static compression, cyclic compression, and cyclic torsion. Humeral constructs stabilized with LCP were significantly stiffer than those plated with LCDCP when loaded in static axial compression (P = 0.0004). When cyclically loaded in axial compression, the LCP constructs were significantly less stiff than the LC-DCP constructs (P = 0.0029). Constructs plated with LCP were significantly less resistant to torsion over 500 cycles than those plated with LC-DCP (P<0.0001). The increased stiffness of LCP constructs in monotonic loading compared to constructs stabilised with non-locking plates may be attributed to the stability afforded by the plate-screw interface of locking plates. The LCP constructs demonstrated less stiffness in dynamic testing in this model, likely due to plate-bone offset secondary to non-anatomic contouring and occasional incomplete seating of the locking screws when using the torque-limiting screw driver. Resolution of these aspects of LCP application may help improve the stiffness of fixation in fractures modeled by the experimental set-up of this investigation.

An In-Vitro Biomechanical Comparison of the Orosco and AO Locking Plates for Anterior Cervical Spine Fixation

1995 ◽  
Vol 8 (3) ◽  
pp. 220-223 ◽  
Author(s):  
Stephen A. Smith ◽  
Ronald W. Lindsey ◽  
Brian J. Doherty ◽  
Jerry Alexander ◽  
Jesse H. Dickson
Keyword(s):  
Cervical Spine ◽  
Locking Plates ◽  
Biomechanical Comparison ◽  
Spine Fixation ◽  
Cervical Spine Fixation

In vitro biomechanical comparison of a newly designed interlocking nail system to a standard DCP

2014 ◽  
Vol 42 (02) ◽  
pp. 79-87 ◽  
Author(s):  
M. Unger ◽  
M. Spies ◽  
M. Brückner
Keyword(s):  
Biomechanical Testing ◽  
Femoral Fractures ◽  
Gap Model ◽  
Application Range ◽  
Interlocking Nail ◽  
Osteosynthesis Plate ◽  
Specialized Equipment ◽  
The Stability ◽  
Biomechanical Comparison

Summary Objective: To describe a newly designed interlocking nail system (Targon® Vet System, TVS) tested in a model of diaphyseal femoral fractures in cats. Material and methods: Introduction of the TVS and presentation of the system components. Evaluation of application range and biomechanical testing of the TVS in cadaver bones under cyclic loading until fatigue failure occurred. The first two test groups compared the influence of implantation and immediate removal of the TVS locking bolts and six holes created by 2.0 mm cortical screws on the stability of feline femora. In the third group the two fixation systems were compared to each other with implants in place in an osteotomy gap model. The failure mode was statistically compared for each group (p < 0.05). Results: Femora after implantation and removal of the bolts of the TVS were significantly stiffer than after implantation and removal of the six 2.0 mm cortical screws. In the osteotomy gap model, femora with the TVS in place failed somewhat later, but not statistically significant, than the opposite femur of the same cat with the 2.0 8-hole DCP in place. Conclusion and clinical relevance: Using this testing method, stability of the TVS seems to be biomechanically comparable to conventional osteosynthesis plate systems. Therefore the TVS may be an encouraging alternative to conventional osteosynthesis systems in diaphyseal fractures, offering several advantages without the need for extensive specialized equipment.

Biomechanical Evaluation of a New Fixation Method for Stabilization of Sagittal Split Ramus Osteotomy After Mandibular Advancement

2021 ◽  
Vol 6 ◽  
pp. 247275122110192
Author(s):  
Karel Kuik ◽  
Jean Pierre T. F. Ho ◽  
Cornelis Klop ◽  
Maurits H. T. de Ruiter ◽  
Cornelis J. Kleverlaan ◽  
...  
Keyword(s):  
Hybrid Method ◽  
In Vitro Study ◽  
Mandibular Advancement ◽  
Fixation Method ◽  
Common Procedure ◽  
Sagittal Split Ramus Osteotomy ◽  
Fixation Methods ◽  
Biomechanical Evaluation ◽  
Monocortical Screws

Study Design: Biomechanical in vitro study. Mandibular advancement after sagittal split ramus osteotomy (SSRO) is a common procedure in orthognathic surgery. Several fixation methods are used for stabilization of SSRO. Objective: The aim of this study was to compare a new fixation method (gridplate) with more contemporary applied methods of fixation. Material and Methods: In this study, 50 polyurethane hemimandibles with a prefabricated SSRO were used as specimens. All hemimandibles were advanced by 8 mm and divided into 5 groups with different fixation methods: (A) one 4-hole miniplate with 4 monocortical screws; (B) two 4-hole miniplates with 8 monocortical screws; (C) one 4-hole miniplate with 4 monocortical screws and 1 bicortical screw in the retromolar area (hybrid method); (D) 3 bicortical screws in an inverted-L pattern; and (E) one 8-hole gridplate with 8 monocortical screws. Loads in newtons were recorded at displacements of the mandibular incisive edge at 1 mm, 3 mm and 5 mm. Results: Fixation with 3 bicortical screws and the gridplate presented the most stability, followed by two 4-hole miniplates. Fixation with the hybrid method or the single miniplate showed the least stability. Conclusion: According to the results of this study, the 8-hole gridplate design appears a sufficient fixation method regarding stabilization of SSRO with larger mandibular advancement.

scholarly journals OP0244 A PRECLINICAL TESTING TOOL: THE IN VITRO 3D FRACTURE GAP MODEL

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 154.1-154
Author(s):  
M. Pfeiffenberger ◽  
A. Damerau ◽  
P. Hoff ◽  
A. Lang ◽  
F. Buttgereit ◽  
...  
Keyword(s):  
Fracture Healing ◽  
Bone Healing ◽  
Inflammatory Markers ◽  
Initial Phase ◽  
Gap Model ◽  
Osteogenic Markers ◽  
Immunosuppressed Patients ◽  
The Impact

Background:Approximately 10% of fractures lead to significant fracture healing disorders, with a tendency to further increase due to the aging population. Of note, especially immunosuppressed patients with ongoing inflammation show difficulties in the correct course of fracture healing leading to fracture healing disorders. Most notably, invading immune cells and secreted cytokines are considered to provide an inflammatory microenvironment within the fracture gap, primarily during the initial phase of fracture healing. Current research has the focus on small animal models, facing the problem of translation towards the human system. In order to improve the therapy of fracture healing disorders, we have developed a human cell-basedin vitromodel to mimic the initial phase of fracture healing adequately. This model will be used for the development of new therapeutic strategies.Objectives:Our aim is to develop anin vitro3D fracture gap model (FG model) which mimics thein vivosituation in order to provide a reliable preclinical test system for fracture healing disorders.Methods:To assemble our FG model, we co-cultivated coagulated peripheral blood and primary human mesenchymal stromal cells (MSCs) mimicking the fracture hematoma (FH model) together with a scaffold-free bone-like construct mimicking the bony part of the fracture gap for 48 h under hypoxic conditions (n=3), in order to reflect thein vivosituation after fracture most adequately. To analyze the impact of the bone-like construct on thein vitroFH model with regard to its osteogenic induction capacity, we cultivated the fracture gap models in either medium with or without osteogenic supplements. To analyze the impact of Deferoxamine (DFO, known to foster fracture healing) on the FG model, we further treated our FG models with either 250 µmol DFO or left them untreated. After incubation and subsequent preparation of the fracture hematomas, we evaluated gene expression of osteogenic (RUNX2,SPP1), angiogenic (VEGF,IL8), inflammatory markers (IL6,IL8) and markers for the adaptation towards hypoxia (LDHA,PGK1) as well as secretion of cytokines/chemokines using quantitative PCR and multiplex suspension assay, respectively.Results:We found via histology that both the fracture hematoma model and the bone-like construct had close contact during the incubation, allowing the cells to interact with each other through direct cell-cell contact, signal molecules or metabolites. Additionally, we could show that the bone-like constructs induced the upregulation of osteogenic markers (RUNX2, SPP1) within the FH models irrespective of the supplementation of osteogenic supplements. Furthermore, we observed an upregulation of hypoxia-related, angiogenic and osteogenic markers (RUNX2,SPP1) under the influence of DFO, and the downregulation of inflammatory markers (IL6,IL8) as compared to the untreated control. The latter was also confirmed on protein level (e.g. IL-6 and IL-8). Within the bone-like constructs, we observed an upregulation of angiogenic markers (RNA-expression ofVEGF,IL8), even more pronounced under the treatment of DFO.Conclusion:In summary, our findings demonstrate that our establishedin vitroFG model provides all osteogenic cues to induce the initial bone healing process, which could be enhanced by the fracture-healing promoting substance DFO. Therefore, we conclude that our model is indeed able to mimic correctly the human fracture gap situation and is therefore suitable to study the influence and efficacy of potential therapeutics for the treatment of bone healing disorders in immunosuppressed patients with ongoing inflammation.Disclosure of Interests:Moritz Pfeiffenberger: None declared, Alexandra Damerau: None declared, Paula Hoff: None declared, Annemarie Lang: None declared, Frank Buttgereit Grant/research support from: Amgen, BMS, Celgene, Generic Assays, GSK, Hexal, Horizon, Lilly, medac, Mundipharma, Novartis, Pfizer, Roche, and Sanofi., Timo Gaber: None declared

Biomechanical Evaluation of a Novel Lumbosacral Axial Fixation Device

2005 ◽  
Vol 127 (6) ◽  
pp. 929-933 ◽  
Author(s):  
Eric H. Ledet ◽  
Michael P. Tymeson ◽  
Simon Salerno ◽  
Allen L. Carl ◽  
Andrew Cragg
Keyword(s):  
Range Of Motion ◽  
Axial Compression ◽  
Bending Stiffness ◽  
Torsional Stiffness ◽  
Lumbosacral Spine ◽  
Presacral Space ◽  
Intact State ◽  
Bony Fusion ◽  
Motion Segment

Background: Interbody arthrodesis is employed in the lumbar spine to eliminate painful motion and achieve stability through bony fusion. Bone grafts, metal cages, composite spacers, and growth factors are available and can be placed through traditional open techniques or minimally invasively. Whether placed anteriorly, posteriorly, or laterally, insertion of these implants necessitates compromise of the anulus—an inherently destabilizing procedure. A new axial percutaneous approach to the lumbosacral spine has been described. Using this technique, vertical access to the lumbosacral spine is achieved percutaneously via the presacral space. An implant that can be placed across a motion segment without compromise to the anulus avoids surgical destabilization and may be advantageous for interbody arthrodesis. The purpose of this study was to evaluate the in vitro biomechanical performance of the axial fixation rod, an anulus sparing, centrally placed interbody fusion implant for motion segment stabilization. Method of Approach: Twenty-four bovine lumbar motion segments were mechanically tested using an unconstrained flexibility protocol in sagittal and lateral bending, and torsion. Motion segments were also tested in axial compression. Each specimen was tested in an intact state, then drilled (simulating a transaxial approach to the lumbosacral spine), then with one of two axial fixation rods placed in the spine for stabilization. The range of motion, bending stiffness, and axial compressive stiffness were determined for each test condition. Results were compared to those previously reported for femoral ring allografts, bone dowels, BAK and BAK Proximity cages, Ray TFC, Brantigan ALIF and TLIF implants, the InFix Device, Danek TIBFD, single and double Harms cages, and Kaneda, Isola, and University plating systems. Results: While axial drilling of specimens had little effect on stiffness and range of motion, specimens implanted with the axial fixation rod exhibited significant increases in stiffness and decreases in range of motion relative to intact state. When compared to existing anterior, posterior, and interbody instrumentation, lateral and sagittal bending stiffness of the axial fixation rod exceeded that of all other interbody devices, while stiffness in extension and axial compression were comparable to plate and rod constructs. Torsional stiffness was comparable to other interbody constructs and slightly lower than plate and rod constructs. Conclusions: For stabilization of the L5-S1 motion segment, axial placement of implants offers potential benefits relative to traditional exposures. The preliminary biomechanical data from this study indicate that the axial fixation rod compares favorably to other devices and may be suitable to reduce pathologic motion at L5-S1, thus promoting bony fusion.

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