Lim T H, Goel V K, Weinstein J N, Kong W
Department of Orthopaedic Surgery, Medical College of Wisconsin 53226.
J Biomech. 1994 Oct;27(10):1259-69. doi: 10.1016/0021-9290(94)90279-8.
Canine models have been frequently employed to investigate the in vivo effects of a surgical procedure. Various studies indicate that canine models can provide a successful in vivo biological model for these studies. Use of canine models for the biomechanical studies of the spine, however, have been questioned because of different loading conditions on the canine and human spines originated from posture differences between canine and human. Similarities between the stress distributions within the canine and human motion segments under physiological loads will strengthen the use of canine models for the studies of spine biomechanics. In the present study, finite element models of the canine intact and stabilized motion segments were developed to investigate these aspects. Comparison of model predicted flexion angle, axial stiffness, and facet contact force for the canine intact L6-L7 motion segment revealed good agreement with the corresponding parameters experimentally measured under the similar loading conditions. Similar stress distributions within the intact canine and human models were found from the predicted results in response to the physiological load. Stabilizing and stress-shielding effects of a pedicle screw-plate-type fixation device [variable spinal plating (VSP)] on the stabilized motion segment were also similar for the canine and human stabilized models. Furthermore, maximum stresses in the pedicle screws were found at the junction between the bone screw and the integrated nut of the inferior screw in both the canine and human stabilized models. This corresponds to the location of pedicle screw breakage reported in the literature. These findings suggest that a canine is a suitable model for the biomechanical studies of the lumbar spine.
犬类模型经常被用于研究外科手术的体内效应。各种研究表明，犬类模型能够为这些研究提供成功的体内生物学模型。然而，由于犬类和人类脊柱的负荷条件因姿势差异而不同，犬类模型在脊柱生物力学研究中的应用受到了质疑。犬类和人类运动节段在生理负荷下应力分布的相似性将加强犬类模型在脊柱生物力学研究中的应用。在本研究中，开发了犬类完整和稳定运动节段的有限元模型来研究这些方面。对犬类完整L6-L7运动节段模型预测的屈曲角度、轴向刚度和小关节接触力的比较表明，与在相似负荷条件下实验测量的相应参数具有良好的一致性。从预测结果中发现，完整犬类模型和人类模型在生理负荷下的应力分布相似。犬类和人类稳定模型中，椎弓根螺钉-钢板型固定装置[可变脊柱钢板固定（VSP）]对稳定运动节段的稳定和应力屏蔽作用也相似。此外，在犬类和人类稳定模型中，椎弓根螺钉的最大应力均出现在下侧螺钉的骨螺钉与一体式螺母的连接处。这与文献报道的椎弓根螺钉断裂位置相对应。这些发现表明，犬类是腰椎生物力学研究的合适模型。
