Abstract: Enhancement of Voluntary Elbow Movement with a Myoelectric Orthotic Device: Long Term Follow Up of a Novel Application of a Post-Cva Assistive Rehabilitation Orthotic Device

Abstract

INTRODUCTION: Free functioning muscle transfers (FFMTs), nerve grafting and nerve transfers have led to improved functional outcomes in brachial plexus injury (BPI) patients. Reports have shown that 39% of FFMTs and 26% of nerve transfers for elbow flexion achieve ≥ M4 elbow flexion strength.1 However, there remains a substantial number of patients with less favorable functional outcomes that need to be addressed further. The MyoPro (Myomo Inc., Cambridge, MA, USA) is a FDA-cleared myoelectric elbow-wrist-hand orthosis that uses surface EMG signals from affected muscle groups to control a powered orthosis to assist with the movement of a paretic upper limb. We describe the application of this orthosis for enhancement of elbow flexion and extension in patients with incomplete recovery from BPI. METHODS: Two patients from a single-surgeon practice have been evaluated for suitability of the myoelectric functional orthotic device. Both patients are 37 year-old men with 14 and 17 years history of left and right BPIs. Patient-1 initially had BP reconstruction by nerve transfers and secondarily a FFMT for restoration of elbow flexion and finger extension. Patient-2 underwent brachial plexus exploration and neurolysis only. Both patients failed to regain voluntary elbow movement. Evaluation showed 0–130 degree elbow passive range of motion in flail arms. Both patients had detectable EMG signals in the biceps or gracilis, and triceps muscles. Patients underwent 30 minutes of training with the device, which provides powered assistance for elbow flexion and extension via motors attached to the exterior of the orthosis. After the training, patients were asked to perform voluntary assisted elbow flexion and extension. Patients were then referred to receive custom orthotic devices. Functional assessment was performed using disabilities of the arm, shoulder and hand (DASH) questionnaire. RESULTS: Both patients demonstrated voluntary active elbow flexion and extension from 0 to 115 degrees using EMG control signals from the gracilis and triceps in Patient-1, and from the biceps and triceps muscles in Patient-2. Patient-1 quitted before getting the custom device. Patient-2 had DASH scores of 44.17 before and 36.6 after 6 months of using the orthotic device. CONCLUSION: Given the limited options available after definitive reconstruction, this myoelectric orthosis is a valuable option to improve the functional outcome in patients with BPI and poor return of voluntary elbow movement following reconstruction. Reference Citations: 1. Maldonado AA, Kircher MF, Spinner RJ, Bishop AT, Shin AY. Free Functioning Gracilis Muscle Transfer versus Intercostal Nerve Transfer to Musculocutaneous Nerve for Restoration of Elbow Flexion after Traumatic Adult Brachial Pan-Plexus Injury. Plast Reconstr Surg. 2016 Sep;138(3):483e-8e.