Evaluating adjacent segment biomechanics after ACDF or TDR surgery in cervical spondylosis patients.

摘要 颈椎病是指与年龄相关的脊柱上部退行性改变。 退行性病变引起的症状可分为轴性颈痛、神经根性颈椎病和颈椎病。 脊髓病(脊髓受累的长管综合征)。中轴颈终生患病率 疼痛约为66%，在任何给定时间，5%的人口都会经历致残疼痛。其中一个 颈椎退行性疾病最常用的处方治疗方法是颈椎前路髓核摘除术和 融合(ACDF)。然而，放射学随访研究显示，多达90%的接受治疗的患者发生 进行性邻近节段疾病(ASD)，高达25.6%的患者需要在邻近节段再次手术 由于有症状的ASD。对ASD的关注一直是开发全盘置换(TDR)的基础 通过保留指标级的运动能力。然而，最近的中长期随机试验报告 比较ACDF和ACDF时相邻节段的临床结果和术后再手术率相似 TDR患者组。邻近节段退变是手术的结果(ACDF或TDR)还是仅仅 代表了这种疾病的自然发展至今仍不清楚。 ASD的病因是多因素的，研究表明邻近节段生物力学改变 手术后可能是一个促成因素。尽管许多成像技术已被用于研究 在活体颈椎运动中，很少有关于运动学和关节运动学变化的数据报道。 脊椎病患者ACDF或TDR手术前后动态、功能和负重的变化 活动。具体地说，没有其他研究对ACDF或TDR前后的患者进行年龄和性别的调查 配对的无症状对照，以说明患者的特定因素，并分离年龄相关的退行性变。 了解增加房间隔缺损风险的生物力学因素对于改进再手术是必要的。 由症状性ASD引起的发病率。 本研究基于颈椎术后相邻节段生物力学改变的假设。 手术与术后邻近节段退变的发展密切相关。首先， 我们将确定运动学(即六自由度运动范围)和关节运动学(即关节盘变形和小关节 在C5-6 ACDF或TDR前后，脊椎病患者相邻节段的关节运动)。运动学 10例ACDF和10例TDR患者相邻节段(C2-C3、C3-C4、C4-C5和C6-C7)的关节运动学 在手术前和术后18个月的功能活动中(动态步态和颈部的全面活动) 手术将会被测量。其次，我们将确定生物力学变化之间的关系 (运动学、关节运动学)和生化成分(T1、ρ和T2松弛值) 患者在ACDF或TDR治疗前后。 这项纵向的前瞻性研究将为深入了解 ACDF或TDR手术后颈椎ASD的生物力学成分。如果我们的假设 得到证实，那么这项研究将帮助临床医生更早地预测症状性退行性变，并改善再手术 通过显示ACDF和TDR中哪个在减少症状性ASD方面更好地提高治愈率。或者，如果没有关联 发现了生物力学和生化组成(T1、ρ和T2映射序列)之间的关系，然后本研究 将表明生物因素是ASD的主要驱动因素，应更多地关注患者 特殊的解剖学和病理学。这一先导数据将用于开发R01随机临床试验研究 医源性和患者可彻底分离ASD生物力学成分的建议 考虑到特定的解剖结构，并使用更大的患者组和更长的随访时间。作为一名医生- 科学家，我的职业目标是通过创新的翻译性基础科学研究和 这项研究是这一目标的核心。

Summary Cervical spondylosis refers to age related degenerative changes in the upper region of the spinal column. Symptoms caused by this degeneration can be classified into axial neck pain, cervical radiculopathy and cervical myelopathy (syndrome of long tract findings from spinal cord involvement). Lifetime prevalence of axial neck pain is approximately 66%, with 5% of the population experiencing disabling pain at any given time. One of the most commonly prescribed treatments for cervical degenerative disorders is anterior cervical discectomy and fusion (ACDF). However, radiographic follow-up studies reveal that as many as 90% of treated patients develop progressive adjacent segment disease (ASD) with up to 25.6% requiring reoperation at an adjacent segment due to symptomatic ASD. Concern for ASD has been the rationale for developing total disc replacement (TDR) through preserving index level motion capability. However, recent mid to long term randomized trials reported similar clinical outcomes and post-operative re-operation rate at adjacent segments when comparing ACDF and TDR patient groups. Whether adjacent segment degeneration is an effect of surgery (ACDF or TDR) or merely represents the natural development of the disease remains unknown. Etiology of ASD is multifactorial and research has shown that altered adjacent level biomechanics following surgery could be a contributing factor. Although many imaging techniques have been used to research in-vivo cervical spine motion, few data have been reported on the changes in kinematics and arthrokinematics in spondylosis patients before and after ACDF or TDR surgery during dynamic, functional and weightbearing activities. Specifically, no other study has investigated patients before and after ACDF or TDR with age and sex matched asymptomatic controls to account for patient specific factors and to separate age-related degeneration. Understanding the biomechanical factors that can increase the risk for ASD is necessary to improve reoperation rate due to symptomatic ASD. This study is based on the hypothesis that the altered adjacent segment biomechanics after cervical surgery are strongly associated with the development of post-operative adjacent segment degeneration. Firstly, we will determine kinematics (i.e. 6DOF range of motion) and arthrokinematics (i.e. disc deformation and facet joint motion) in the adjacent segments in spondylosis patients before and after a C5-6 ACDF or TDR. Kinematics and arthrokinematics at adjacent segments (C2-C3, C3-C4, C4-C5 and C6-C7) in 10 ACDF and 10 TDR patients during functional activities (dynamic gait and full range of motion of the neck) before surgery and 18 months after surgery will be measured. Secondly, we will determine the relationship between the changes in biomechanics (kinematics, arthrokinematics) and biochemical composition (T1ρ and T2 relaxation values) in the spondylosis patients before and after an ACDF or TDR. This longitudinal, prospective study will provide pilot data for an in-depth understanding of the biomechanical component of cervical spine ASD after undergoing an ACDF or a TDR surgery. If our hypothesis is confirmed then this study will help clinicians predict symptomatic degeneration earlier and improve reoperation rate by showing whether ACDF or TDR is better at reducing symptomatic ASD. Alternatively, if no association between biomechanical and biochemical composition (T1ρ and T2 mapping sequences) is found, then this study will show that biological factors are the main drivers of ASD and increased attention should be placed on patient specific anatomy and pathology. This pilot data will be used to develop a R01 randomized clinical trial research proposal that can thoroughly isolate the biomechanical component of ASD by taking iatrogenic and patient specific anatomy in consideration and using a larger patient group with longer follow-up times. As a physician- scientist, it is my career goal to improve patient care through innovative translational basic science research and this research is at the heart of that goal.