Electrophysiological Evaluation of a Patient With Chronic Erb-Duchenne Palsy (C5-C6): A Case Study

Abstract

Background Erb-Duchenne palsy describes injury to the upper trunk of the brachial plexus or the C5 and C6 nerve roots. It typically occurs from a traction injury that increases the angle between the head and shoulder girdle, placing excessive strain on the cervical nerve roots and brachial plexus. Injury to the C5 and C6 nerve roots and/or upper trunk of the brachial plexus results in severe shoulder girdle weakness with preservation of the hand intrinsic muscles and some forearm motions. 2 , 9 Case Presentation A 64-year-old right-hand–dominant male was referred by his orthopaedic surgeon for electromyograhy (EMG) and nerve conduction studies (NCS) to evaluate the nerve and muscle structures in the right upper extremity prior to surgical fusion of the glenohumeral joint for chronic humeral head subluxation and shoulder instability. The patient was diagnosed with a right Erb-Duchenne palsy following a hit-and-run motor vehicle accident in 2001. Physical examination revealed muscle weakness in all muscles representative of the right C5-C6 myotomes and absent biceps brachii and brachioradialis muscle stretch reflexes. Outcome and Follow Up The clinical exam findings and electrophysiological testing evidence suggested that the patient had a chronic right C5-C6 radiculopathy affecting the right upper extremity and the right mid cervical paravertebral muscles, consistent with the referring diagnosis of Erb-Duchenne palsy. Needle EMG findings suggested little chance of further neurological recovery, so the patient underwent a right glenohumeral joint fusion to improve the stability of the right shoulder and limit glenohumeral subluxation. Discussion This case study highlights the role of a thorough neuromusculoskeletal exam in the differential diagnostic process for a patient with a right C5-C6 Erb-Duchenne palsy, and the role of EMG and NCS in distinguishing brachial plexopathy from cervical radiculopathy. Additionally, EMG and NCS provided prognostic information on potential neurological recovery, suggesting that surgical fusion was the best intervention. JOSPT Cases 2022;2(3):152–158. Epub: 21 June 2022. doi:10.2519/josptcases.2022.11174