A Pilot Study on the Functional Outcome using Markerless Motion Analysis Tool and Surface EMG of Nerve Transfers for Upper Trunk Brachial Plexus Injuries

Abstract

Introduction. Brachial plexus injuries (BPI) have devastating functional effects. Clinical outcomes of BPI reconstruction have been documented in literature; however, these do not use EMG and quantitative kinematic studies.Objective. This study aims to use a markerless motion analysis tool (KINECT) and surface EMG to assess the functional outcomes of adult patients with traumatic upper trunk BPI who have undergone nerve transfers for the shoulder and elbow in comparison to the normal contralateral limb.Methods. This is an exploratory study which evaluated three participants with BPI after nerve reconstruction. KINECT was used to evaluate the kinematics (range of motion, velocity, and acceleration) and the surface EMG for muscle electrical signals (root mean square, peak EMG signal, and peak activation time) of the extremities. The means of each parameter were computed and compared using t-test or Mann-Whitney U test.Results. Participant C, with the best clinical recovery, showed mostly higher KINECT and EMG values for the BPIextremity. There was a significant difference between the KINECT data of Participants A and B, with lower meanvalues for the BPI extremity. Most of the EMG results showed lower signals for the BPI extremity, with statisticalsignificance.Conclusion. The KINECT and surface EMG provide simple, cost-effective, quick, and objective assessment tools.These can be used for monitoring and as basis for formulating individualized interventions. A specific algorithm should be developed for the KINECT sensors to address errors in data collection. A fine needle EMG may be more useful in evaluating the muscles involved in shoulder external rotation.