Khuyagbaatar Batbayar, Kim Kyungsoo, Purevsuren Tserenchimed, Lee Sang-Hun, Kim Yoon Hyuk
Department of Mechanical Engineering, Kyung Hee University, Yongin 17104, South Korea e-mail: .
Department of Applied Mathematics, Kyung Hee University, Yongin 17104, South Korea e-mail: .
J Biomech Eng. 2018 Jul 1;140(7). doi: 10.1115/1.4039826.
Many clinical case series have reported the predisposing factors for C5 palsy and have presented comparisons of the two types of laminoplasty. However, there have been no biomechanical studies focusing on cervical spinal cord and nerve root following laminoplasty. The purpose of this study is to investigate biomechanical changes in the spinal cord and nerve roots following the two most common types of laminoplasty, open-door and double-door laminoplasty, for cervical ossification of the posterior longitudinal ligament (OPLL). A finite element (FE) model of the cervical spine and spinal cord with nerve root complex structures was developed. Stress changes in the spinal cord and nerve roots, posterior shift of the spinal cord, and displacement of the cervical nerve roots were analyzed with two types of cervical laminoplasty models for variations in the degree of canal occupying ratio and shape of the OPLL. The shape and degree of spinal cord compression caused by the OPLL had more influence on the changes in stress, posterior shift of the spinal cord, and displacement of the nerve root than the type of laminoplasty. The lateral-type OPLL resulted in imbalanced stress on the nerve roots and the highest nerve root displacement. Type of laminoplasty and shape and degree of spinal cord compression caused by OPLL were found to influence the changes in stress and posterior displacement of the cervical spinal cord and nerve roots. Lateral-type OPLL might contribute to the development of C5 palsy due to the imbalanced stress and tension on the nerve roots after laminoplasty.
许多临床病例系列报告了C5麻痹的诱发因素，并对两种类型的椎板成形术进行了比较。然而，尚未有针对椎板成形术后颈脊髓和神经根的生物力学研究。本研究的目的是调查在治疗后纵韧带骨化症（OPLL）时，两种最常见的椎板成形术，即单开门和双开门椎板成形术后脊髓和神经根的生物力学变化。建立了包含神经根复杂结构的颈椎和脊髓有限元（FE）模型。使用两种颈椎椎板成形术模型，针对椎管占位率和OPLL形状的变化，分析脊髓和神经根的应力变化、脊髓后移以及颈神经根的位移。与椎板成形术类型相比，OPLL导致的脊髓受压形状和程度对应力变化、脊髓后移和神经根位移的影响更大。外侧型OPLL导致神经根应力失衡和最高的神经根位移。研究发现，椎板成形术类型以及OPLL导致的脊髓受压形状和程度会影响颈脊髓和神经根的应力变化及后移。外侧型OPLL可能由于椎板成形术后神经根上的应力和张力失衡而导致C5麻痹的发生。
