Double crush syndrome

Upton and McComas formalized the hypothesis of the "double crush" syndrome (DCS) in 1973 to describe the coexistence of multiple compressive lesions along the course of a peripheral nerve, postulating that entrapment of the peripheral nerve at one site renders the nerve susceptible to proximal and/or distal compression. By definition, augmented axonal injury occurs, representing more than just the combined independent effects of each lesion. This mechanism of neuronal injury is implicated in a variety of multi-focal neuropathies, including cervical radiculopathy and carpal tunnel syndrome (CTS), thoracic outlet syndrome and CTS, and cubital tunnel syndrome and Guyon's canal syndrome. The DCS hypothesis, however, is not universally accepted as an underlying mechanism of multi-focal neuropathies, and a critical review of this entity allows for a better understanding of the controversial theory.