Elbow reconstruction biomechanics in tetraplegia

Using neural stimulation techniques, we have quantified voluntary activation and corticomotor excitability of surgically transferred muscle in individuals with quadriplegia resulting from SCI. We are using the Simtk forum to share the data we collected. Our publications should be referenced for detailed information regarding our objectives, subjects, methods, and results. Here, we provide a summary of our work. We found that maximum voluntary activation (percentage of the motorneuron pool that can be voluntarily recruited during maximum effort) is more complete in individuals with quadriplegia who have undergone biceps-to-triceps transfer relative to those who have undergone posterior deltoid-to-triceps transfer. Both the biceps-to-triceps and the posterior deltoid-to-triceps transfers are surgical procedures that enable active elbow extension via reassignment of a nonparalyzed donor muscle (biceps or deltoid) to the insertion of the paralyzed triceps. The greater voluntary activation after biceps transfer we found in functionally relevant postures augmented the greater force generating capacity of the biceps muscle, leading to increased post-surgery elbow extension strength relative to when the posterior deltoid is transferred. In another study, using transcranial magnetic stimulation to non-invasively stimulate the motor cortex, we found that posture-dependent excitability of the corticomotor pathway to the biceps is altered following SCI and surgical transfer relative to the nonimpaired biceps. Thus, if initial training of the transferred biceps is facilitated in postures that correspond to greatest corticomotor excitability, training postures cannot be based on the excitability of the nonimpaired biceps. <br/><br/>This project includes the following software/data packages: <br/> <ul> <li> <a href="https://simtk.org/frs?group_id=1232#pack_1921">Corticomotor Excitability Data </a> : Normalized motor evoked potentials (MEPs) were recorded using transcranial magnetic stimulation from the biceps of nonimpaired individuals and individuals with biceps transfer and tetraplegia to compare posture-dependent corticomotor excitability. MEPs were normalized to the horizontal plane posture with the forearm oriented in neutral for each subject. Please note the numeric descriptors in the data file for the main postures (horizontal plane, overhead reach, pressure relief), forearm orientation (neutral, supinated), and population (nonimpaired, biceps transfer and tetraplegia). Please see our publication for further details. </li> <li> <a href="https://simtk.org/frs?group_id=1232#pack_1922">Voluntary Activation Data </a> : The purpose of this study was to quantify the ability of individuals to voluntarily activate transferred muscles during maximum isometric elbow extension. Here we share our voluntary activation and maximum elbow extensor moment data across functional postures in individuals with tetraplegia and either biceps-to-triceps transfer or posterior deltoid-to-triceps transfer. Numbers to differentiate individual arms in the data file corresponding to the arms of individuals described in Table 1 in our publicaiton. Please see our publication for details regarding the experimental protocol, data analyses, participant demographics, and relevance to rehabilitation. </li> </ul>

采用神经刺激技术，我们已对脊髓损伤（SCI）导致的截瘫患者术中转移的肌肉的自愿激活和皮层运动兴奋性进行了量化。我们正利用 Simtk 论坛分享我们所收集的数据。关于我们的目标、受试者、方法和结果等详细信息，请参阅我们的出版物。在此，我们提供工作的概要。我们发现，与进行后三角肌至三头肌转移的患者相比，进行肱二头肌至三头肌转移的截瘫患者在最大自愿激活（在最大努力下可自愿募集的运动神经元池的百分比）方面更为完整。肱二头肌至三头肌和后三角肌至三头肌的转移都是通过重新分配非瘫痪供体肌肉（肱二头肌或三角肌）到瘫痪三头肌的附着点，以实现主动肘关节伸展的手术过程。我们发现，在功能相关姿势中，肱二头肌转移后的更大自愿激活增加了肱二头肌的更大力生成能力，相对于后三角肌转移，导致术后肘关节伸展力量增加。在另一项研究中，我们使用经颅磁刺激非侵入性地刺激运动皮层，发现相对于未受损伤的肱二头肌，SCI 和手术转移后皮质运动通路对肱二头肌的姿势依赖性兴奋性发生了改变。因此，如果初始训练的转移肱二头肌在对应最大皮质运动兴奋性的姿势中得到促进，则训练姿势不能基于未受损伤肱二头肌的兴奋性。

本项目中包含以下软件/数据包：

<ul>
<li> <a href="https://simtk.org/frs?group_id=1232#pack_1921">皮质运动兴奋性数据</a>：使用经颅磁刺激从非受损伤个体和进行肱二头肌转移和截瘫个体的肱二头肌记录了标准化运动诱发电位（MEPs），以比较姿势依赖性皮质运动兴奋性。MEPs 已标准化为每个受试者前臂在中性位置的水平面姿势。请注意数据文件中的数值描述符，包括主要姿势（水平面、过头伸展、减压）、前臂方向（中性、旋后）和人群（非受损伤、肱二头肌转移和截瘫）。请参阅我们的出版物以获取更多详细信息。</li>
<li> <a href="https://simtk.org/frs?group_id=1232#pack_1922">自愿激活数据</a>：本研究旨在量化个体在最大等长肘关节伸展时自愿激活转移肌肉的能力。在此，我们分享了对截瘫患者进行肱二头肌至三头肌转移或后三角肌至三头肌转移的自愿激活和最大肘关节伸展力矩数据。数据文件中的数字用于区分对应于出版物中表1中描述的个体手臂的各个手臂。请参阅我们的出版物以获取有关实验方案、数据分析、参与者人口统计学和与康复相关性的详细信息。</li>
</ul>