Radial nerve lesion of the distal upper arm in patients with "tennis elbow"
Gutjahr, L.; Pietschker, K.
Der Nervenarzt 62(2): 116-122
1991
ISSN/ISBN: 0028-2804 PMID: 2034306 Document Number: 370147
Thirty-five healthy subjects and 38 patients with tennis elbow underwent electromyographic studies of the long radial extensor muscle of the wrist (LREM) and motor latency measurements of the radial nerve innervating this muscle following supramaximal stimulation of the distal, middle, and proximal upper arm as well as the axilla. Fifteen out of 31 patients showed significantly longer latency during stimulation of the distal upper arm, and 14 out of 38 patients had a significantly elevated rate of polyphasia; in 8 out of 31 patients, both parameters were significantly different. Discriminant analysis showed 85% of the healthy subjects and 74% of the patients were classified properly. In some of the patients, the close relationship between "epicondylitis humeri radials" and neurogenic lesions seems to be based on damage to the branch of the radial nerve which innervates the LREM, due apparently to connective tissue emtrapment of the radial nerve in the lateral bicipital sulcus. This was confirmed surgically in 2 patients. If the nerve is fixed in this sulcus, a backwards extension of the flexed radial extensor muscle can lead to strain injuries of the innervating nerve branches. Lesion of the motor branch of the radial nerve can be accompanied by damage to nociceptive fibers of the LREM. Acute (neuropathic) pain can be caused locally, voluntary movement can increase pain through the activity of flexor reflex afferents, and a chronic pain syndrome can arise in the absence of a supraspinal defense pattern.