Development of an electrically driven elbow orthosis for patients with severe weakness of elbow flexors

肩部外展的一个突出弱点是一些颈椎病病例是一种容易识别的残疾。在这些患者中，运动障碍还涉及肩关节外旋肌，在较小程度上还涉及肘屈肌，通常没有明显的感觉丧失。这种情况称为“颈椎病肌肉萎缩”，“分离性运动丧失”，或“肩带盘”，可能是节段性脊髓或神经根受累所致。更新的名称，‘术后C-5神经根病’，意味着这种综合征相对频繁地出现在颈椎减压手术的神经系统并发症中。由于严重的轴突丧失后肘屈肌恢复不佳，尽管保留了手指的精细运动，但患者仍难以进食和扣起纽扣。为了给这类患者提供屈肘功能，我们开发了一种电动矫形器。我们在标准的肘关节矫形器上安装了一个马达(DME44SA-12V，日本Servo公司，日本)和一个减速器(CDF-11-30-2A-R，Harmonic Drive公司)。放置在二头肌上的一对表面电极捕捉到的肌电放电激活了马达。印刷电路板被开发出来，以便可以通过二头肌的肌电放电的大小来控制电机输出。由附近电器的静电或电磁场引起的60赫兹干扰产生的伪影通过指定高频和低频过滤器来控制。开关闭合和断开时产生的电噪声，通过屏蔽整个电路将其降至最低。

A prominent weakness of shoulder abduction characterizes some cases of cervical spondylosis as an easily recognizable disability. In such patients, the motor deficits also involve external rotators of the shoulder and, to a lesser degree, elbow flexors, usually without a clear sensory loss. This condition called 'cervical spondylotic amyotrophy', 'the dissociated motor loss', or 'the shoulder girdle disc', probably results from segmental cord or root involvement. More recent designation, 'postoperative C-5 radiculopathy', implies a relatively frequent appearance of this syndrome as a neurologic complication of a decompressive cervical spine surgery. As a result of poor recovery of the elbow flexors after severe axon loss, the patients have difficulty in feeding oneself and doing up buttons despite fine finger movement preserved. To provide elbow flexion in such patients, we developed an electrically driven orthosis. We attached a motor (DME44SA-12V, Japan Servo Corp, Japan) with a decelerator (CDF-11-30-2A-R, Harmonic Drive Corp) to the standard elbow orthosis. The electromyographic discharge that was picked up with a pair of surface electrodes placed on the biceps muscle activated the motor. The printed circuit plate was developed so that the motor output can be controlled by the magnitude of the electromyographic discharge of the biceps muscle. Artifacts resulting from 60 Hz interference caused by the electrostatic or electromagnetic fields of nearby electrical appliances were controlled by specifying high- and low-frequency filters. The electric noise occurring when the switch closes and opens and was minimized by shielding the entire circuit.