Hijjawi John B, Kuiken Todd A, Lipschutz Robert D, Miller Laura A, Stubblefield Kathy A, Dumanian Gregory A
Chicago, Ill. From the Department of Surgery, Division of Plastic Surgery, and Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, and the Neural Engineering Center for Artificial Limbs, Rehabilitation Institute of Chicago.
Plast Reconstr Surg. 2006 Dec;118(7):1573-1578. doi: 10.1097/01.prs.0000242487.62487.fb.
The control of shoulder-level disarticulation prostheses is significantly more difficult than that of prostheses for more distal amputations. Amputees have significant difficulties coordinating the separate functions of prosthetic shoulder, elbow, wrist, and hand/hook components. The user must lock one joint at a particular position in space before subsequently moving a different joint.
A patient with bilateral humeral disarticulations after an electrical injury underwent a novel nerve transfer procedure designed to improve the control of a myoelectric prosthesis. The median, radial, ulnar, and musculocutaneous nerves were transferred to the nerves of segments of the pectoralis major and minor muscles. Those muscles then act as bioamplifiers of peripheral nerve signals when the normal upper extremity nerves are activated by the patient's brain. Therefore, when the patient thinks "flex elbow," the transferred musculocutaneous nerve fires, and a segment of the pectoralis major contracts. An electromyographic signal is then detected transcutaneously and causes the prosthetic elbow to flex.
Three of the four nerve transfers were successful. One of the nerve transfers unexpectedly yielded two separate controllable muscle segments. Standardized testing using a "box-and-blocks" apparatus was performed with the patient's previous myoelectric device and the current device after nerve transfers. The patient's performance improved by 246 percent.
Nerve transfers to small muscle segments are capable of creating a novel neural interface for improved control of a myoelectric prosthesis. This is done using standard techniques of nerve and flap surgery, and without any implantable devices.
肩部离断假肢的控制比更低位截肢的假肢控制要困难得多。截肢者在协调假肢肩部、肘部、腕部和手部/钩部组件的独立功能方面存在重大困难。使用者必须先将一个关节锁定在空间中的特定位置，然后才能移动另一个关节。
一名因电击伤导致双侧肱骨离断的患者接受了一种旨在改善肌电假肢控制的新型神经移植手术。正中神经、桡神经、尺神经和肌皮神经被移植到胸大肌和胸小肌各节段的神经上。当患者大脑激活正常上肢神经时，这些肌肉随后充当周围神经信号的生物放大器。因此，当患者想到“屈肘”时，被移植的肌皮神经会放电，胸大肌的一个节段会收缩。然后经皮检测到肌电信号，并使假肢肘部弯曲。
四次神经移植中有三次成功。其中一次神经移植意外产生了两个独立的可控肌肉节段。使用“积木”装置对患者先前的肌电装置和神经移植后的当前装置进行了标准化测试。患者的表现提高了246%。
向小肌肉节段进行神经移植能够创建一个新型神经接口，以改善肌电假肢的控制。这是通过神经和皮瓣手术的标准技术完成的，无需任何植入设备。
