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Biomechanical Comparison of Different Numbers and Configurations of Cross-Links in Long-Segment Spinal Fixation—An Experimental Study in a Porcine Model

STUDY DESIGN: Biomechanical study. OBJECTIVE: Cross-links are a type of common clinical spinal instrumentation. However, the effects of the position and number of cross-links have never been investigated in long-segment spinal fixation, and the variables have not been optimized. We conducted an in v...

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Detalles Bibliográficos
Autores principales: Hsieh, Ming-Kai, Liu, Mu-Yi, Tsai, Tsung-Ting, Lai, Po-Liang, Tai, Ching-Lung
Formato: Online Artículo Texto
Lenguaje:English
Publicado: SAGE Publications 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9837523/
https://www.ncbi.nlm.nih.gov/pubmed/33511875
http://dx.doi.org/10.1177/2192568221990646
Descripción
Sumario:STUDY DESIGN: Biomechanical study. OBJECTIVE: Cross-links are a type of common clinical spinal instrumentation. However, the effects of the position and number of cross-links have never been investigated in long-segment spinal fixation, and the variables have not been optimized. We conducted an in vitro biomechanical study by using a porcine long-segment spinal model with 5 different crosslink configurations to determine the optimal construct for clinical practice. METHODS: Five modalities with paired segmental screws from T15-L5 were tested in 20 porcine spines. The spines without cross-links composed the control group, Group A; those with a single cross-link from L2-3 composed Group B; those with 2 cross-links from L1-2 and L3-4 composed Group C; those with 2 cross-links from T15-L1 and L4-5 composed Group D; and those with 3 cross-links from T15-L1, L2-3 and L4-5 composed Group E. Spinal stiffnesses in flexion, extension, lateral bending, and axial rotation were compared among 5 different cross-link configurations in 5-level porcine spinal units. RESULTS: Flexional, extensional and lateral bending stiffnesses did not significantly change with an increasing number of cross-links or positions in the construct. Axial stiffness was significantly increased with 2 cross-links compared to one (P < 0.05) and with placement more distant from the center of the long spinal fixation construct (P < 0.05). CONCLUSIONS: Two cross-links individually placed proximal and distal from the center of a construct is an optimal and efficient configuration to achieve biomechanical stability in non-rigid lumbar spines undergoing long-level fixation.