BACKGROUND CONTEXT

Dynamic kinematic evaluation of spino-pelvic alignment during gait using three-dimensional (3D) motion analysis has been proposed for adult spinal thoracolumbar deformity. That is because conventional full-spine radiographs cannot be used to evaluate dynamic factors. However, dynamic changes in spino-pelvic alignment during gait for dropped head syndrome (DHS) have not been studied using this approach.

PURPOSE

: This study aimed to assess the dynamic changes in spinal-pelvic alignment during gait in patients with DHS using 3D motion analysis.

STUDY DESIGN

Retrospective review of collected radiographic and kinematic data.

PATIENT SAMPLE

Nineteen DHS patients with neck pain and/or anterior gaze disturbance.

OUTCOME MEASURES

Static spino-pelvic radiological alignment, dynamic spino-pelvic kinematic parameters and electromyogram (EMG) data.

METHODS

Center of gravity of the head - C7 sagittal vertical axis (CGH-C7 SVA), C2-C7 SVA, T1 slope; cervical lordosis (CL), C7SVA, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic tilt (PT) and pelvic incidence (PI) were assessed using full-spine radiographs in a standing position to assess static spino-pelvic alignment. The 3D gait motion analysis was conducted during gait. Dynamic kinematic parameters were divided into spinal segments: cervical (C-), thoracic (T-), lumbar (L-) and pelvis (P-). Each spinal segment coronal angle to the pelvic angle, each spinal segment sagittal angle to the pelvic angle and pelvic sagittal angle to the horizontal axis were assessed as dynamic spino-pelvic kinematic parameters. Trunk and lower limb muscle activity during gait were assessed using wireless surface EMG analysis. Dynamic spino-pelvic kinematic variables and muscle activity were compared between the first walking lap and the final lap during gait analysis. The change in dynamic kinematic parameters was correlated with static radiological alignment and electromyographic muscular activity change.

RESULTS

Cervical and thoracic anterior tilt increased significantly after an extended period of walking, indicating that dropped head worsened during gait. An increase of cervical anterior tilt during walking was significantly associated with decreased muscle activity in the cervical paraspinal muscles (r=-0.463, P<.05) and latissimus dorsi (r=-0.763, p<.01). Furthermore, significant correlations were found between a change in thoracic sagittal angle to pelvic angle and C7SVA (r=0.683, p<.01) and LL (r=-0.475, p<.05). This means that a larger C7SVA and smaller LL were associated with increased thoracic anterior tilt during gait.

CONCLUSIONS

The 3D motion analysis for DHS showed that cervical and thoracic anterior tilt significantly increased after extended walking, resulting in worsening of dropped head. Decreased muscle activity of the neck extensor muscles during gait suggests insufficient neck extensor muscle endurance, which was associated with increased cervical anterior tilt. A greater increase in the thoracic anterior tilt during gait was found in DHS patients with a larger C7SVA and smaller LL due to insufficient thoracolumbar compensation for the dropped head. Correction of the cervical spine alone would not be sufficient to improve dropped head in cases with increased thoracic anterior tilt during gait. The results suggest that C7SVA and LL are crucial parameters in the surgical strategy for DHS.

中文翻译：

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使用三维步态运动分析评估低头综合征的动态脊柱排列变化和补偿

背景语境

已针对成人脊柱胸腰椎畸形提出了使用三维 (3D) 运动分析对步态期间脊柱-骨盆对齐进行动态运动学评估。这是因为传统的全脊柱 X 光片不能用于评估动态因素。然而，尚未使用这种方法研究低头综合征 (DHS) 步态期间脊柱骨盆对齐的动态变化。

目的

：本研究旨在使用 3D 运动分析评估 DHS 患者步态期间脊柱-骨盆排列的动态变化。

学习规划

对收集的射线照相和运动学数据进行回顾性审查。

患者样本

19 名患有颈部疼痛和/或前凝视障碍的 DHS 患者。

结果测量

静态脊柱-骨盆放射学对准、动态脊柱-骨盆运动学参数和肌电图 (EMG) 数据。

方法

头部重心——C7矢状垂直轴（CGH-C7 SVA），C2-C7 SVA，T1斜率；颈椎前凸(CL)、C7SVA、胸椎后凸 (TK)、腰椎前凸 (LL)、骨盆倾斜度 (PT) 和骨盆倾斜度 (PI) 使用站立位的全脊柱 X 光片进行评估，以评估静态脊柱-骨盆对齐。3D 步态运动分析是在步态期间进行的。动态运动学参数分为脊柱节段：颈椎 (C-)、胸椎 (T-)、腰椎 (L-) 和骨盆 (P-)。每个脊柱节段与骨盆角的冠状角、每个脊柱节段与骨盆角的矢状角和与水平轴的骨盆矢状角被评估为动态脊柱-骨盆运动学参数。使用无线表面 EMG 分析评估步态期间的躯干和下肢肌肉活动。在步态分析期间，比较了第一圈和最后一圈之间的动态脊柱-骨盆运动学变量和肌肉活动。

结果

长时间行走后，颈椎和胸椎前倾显着增加，表明在步态过程中下垂的头部更加严重。行走时颈椎前倾的增加与颈椎旁肌 (r=-0.463, P<.05) 和背阔肌 (r=-0.763, p<.01) 的肌肉活动减少显着相关。此外，还发现胸椎矢状角与骨盆角的变化与 C7SVA (r=0.683, p<.01) 和 LL (r=-0.475, p<.05) 之间存在显着相关性。这意味着较大的 C7SVA 和较小的 LL 与步态期间胸椎前倾增加有关。

结论

DHS 的 3D 运动分析显示，长时间行走后颈椎和胸椎前倾明显增加，导致头下垂恶化。步态期间颈部伸肌的肌肉活动减少表明颈部伸肌耐力不足，这与颈椎前倾增加有关。在 C7SVA 较大和 LL 较小的 DHS 患者中发现步态期间胸椎前倾的增加更大，这是由于胸腰椎对下垂头部的代偿不足。在步态期间胸椎前倾增加的情况下，仅靠颈椎矫正不足以改善头部下垂。结果表明，C7SVA 和 LL 是 DHS 手术策略中的关键参数。