TY - JOUR
T1 - Cervical spine fusion
T2 - Biomechanics of a three-level cadaver model comparing anterior plate versus stand-alone cage
AU - McGuire, Robert
AU - Al-Barghouthi, Abeer
AU - Dale, Wood
AU - Travascio, Francesco
AU - Latta, Loren
N1 - Funding Information:
Partial support for supplies and the use of testing facilities was provided by Zavation Medical Products, LLC. Potential conflicts of interest are as follows: Robert McGuire, MD, reports “other” from Zava-tion, null during the conduct of this study; receives fees from Rehab, Inc., null outside the current study; has a patent pending on a compound to treat osteo-porosis; and is president of the AO Foundation.
Publisher Copyright:
© 2020 by Begell House, Inc. www.begellhouse.com.
PY - 2020
Y1 - 2020
N2 - Study Design—Biomechanical cadaveric study. Objective—Long anterior cervical plate and cage (APC) constructs have a risk of pseudarthrosis with minor bone resorp-tion. Stand-alone cages (SACs) allow settling. The biomechanics of SAC have been investigated, but not multilevel, compression screw SAC. The purpose of this study is to evaluate the biomechanical safety of three-level SAC versus APC. Methods—Discectomies at three levels of five human cadaver spines (T1-C3) were fixed with SAC. A 0.18 mm thick shim was interposed between the cage and the superior endplate, and a pressure transducer map was placed between the cage and the inferior endplate. Tests were performed in flexion-extension and then repeated after removing the shims to simulate minor bone resorption. Subsequently, APC was applied and experiments were repeated. The pressure between each cage and endplate and motion of the implants were measured. Results—The range of motion (ROM) of SAC and APC constructs were comparable. The contact area and pressure between cage and endplate did not significantly change during motion with SAC. Shim removal did not significantly affect ROM, contact area, or average pressure measures. For APC, both contact area and pressure decreased from extension to flexion. Shim removal caused a significant loss of contact area and pressure. Conclusions—SAC provided comparable rigidity to the conventional APC construct while maintaining compression at the endplate-cage interface throughout flexion-extension and after minor bone resorption.
AB - Study Design—Biomechanical cadaveric study. Objective—Long anterior cervical plate and cage (APC) constructs have a risk of pseudarthrosis with minor bone resorp-tion. Stand-alone cages (SACs) allow settling. The biomechanics of SAC have been investigated, but not multilevel, compression screw SAC. The purpose of this study is to evaluate the biomechanical safety of three-level SAC versus APC. Methods—Discectomies at three levels of five human cadaver spines (T1-C3) were fixed with SAC. A 0.18 mm thick shim was interposed between the cage and the superior endplate, and a pressure transducer map was placed between the cage and the inferior endplate. Tests were performed in flexion-extension and then repeated after removing the shims to simulate minor bone resorption. Subsequently, APC was applied and experiments were repeated. The pressure between each cage and endplate and motion of the implants were measured. Results—The range of motion (ROM) of SAC and APC constructs were comparable. The contact area and pressure between cage and endplate did not significantly change during motion with SAC. Shim removal did not significantly affect ROM, contact area, or average pressure measures. For APC, both contact area and pressure decreased from extension to flexion. Shim removal caused a significant loss of contact area and pressure. Conclusions—SAC provided comparable rigidity to the conventional APC construct while maintaining compression at the endplate-cage interface throughout flexion-extension and after minor bone resorption.
KW - Anterior cage
KW - Bone resorption
KW - Cage-endplate pressure
KW - Contact area
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U2 - 10.1615/JLongTermEffMedImplants.2020035807
DO - 10.1615/JLongTermEffMedImplants.2020035807
M3 - Article
C2 - 33426853
AN - SCOPUS:85093082840
VL - 30
SP - 135
EP - 140
JO - Journal of Long-Term Effects of Medical Implants
JF - Journal of Long-Term Effects of Medical Implants
SN - 1050-6934
IS - 2
ER -