CERVICAL RADICULOPATHY AND COEXISTING DISTAL ENTRAPMENT NEUROPATHIES - DOUBLE-CRUSH SYNDROMES

The double-crush hypothesis (DCH) proposes that a proximal lesion alon g an axon predisposes it to injury at a more distal site along its cou rse through impaired axoplasmic flow. Although this hypothesis has bee n accepted, it has anatomic and pathophysiologic restrictions that lim it its application as an explanation for coexisting cervical root lesi ons (CRLs) and carpal tunnel syndrome (CTS) or ulnar neuropathy at the elbow (UN-E). We retrospectively surveyed all electrodiagnostic (EDX) reports of coexisting CTS or UN-E and CRL for anatomic correlation, i f any, between the proximal root lesion and the distal entrapment neur opathy. In the period between January 1982 and August 1995 there were 12,736 limbs with CTS or UN-E. In 435 of these limbs (3.4%) there was a coexisting CRL, but only 98 (0.8%) had an association that was anato mically appropriate. Moreover, only 69 (0.5%) of the 98 cases demonstr ated axon loss at the distal lesion site on EDX examination. Therefore , cumulatively, only 69 of our 12,736 cases of CTS and UN-E satisfied the pathophysiologic and one of the anatomic requirements of the DCH. Our data thus suggest that a CRL can seldom serve as the proximal lesi on with these entrapment neuropathies in the DCH.