A Electrodiagnostic Study on Relationship of the Double Crush Syndrome to Carpal Tunnel Syndrome: a Preliminary Study

ABSTRACT

BACKGROUND: The concept of "double crush syndrome (DCS)"-a proximal compressive lesion making the distal nerve more vulnerable to injury-is an intriguing hypothesis. However, recent studies did not show unitary results. This study was preliminarily undertaken in order to clarify the causal relationship of proximal compressive lesion and carpal tunnel syndrome (CTS) in an electrophysiologic aspect. METHODS: In the period between June 1998 and June 1999 there were 24 patients with CTS(33 limbs with CTS). With these CTS patients, thorough electrodiagnostic studies were performed to discover coexisting proximal compressive lesions along the median nerve and its corresponding cervical root lesions. RESULTS: In 10 of these limbs (30%), there was a electrodiagnostically-proven coexisting proximal compressive lesion(all cervical radiculopathies). But only 1 limb (3%) had an anatomically responsible association. Finally only 1 limb (3%) with CTS had a possibility of DCS. CONCLUSIONS: CTS and cervical radiculopathy are common disorders, so there is a high possibility of coexisting as a double primary lesion without a pathophysiological relationship. Our results do not support the double crush hypothesis. However, the possibility of a reversed double crush syndrome is suggested.