[Double crush syndrome in patients with cervical spondylosis or ossification of posterior longitudinal ligament--a clinicophysiological study].

To clarify the clinical characteristics of double crush syndrome (DCS), we evaluated 207 patients with cervical spondylosis (CS) and 19 with ossification of posterior longitudinal ligament of the cervical spine (OPLL) clinicophysiologically. A diagnosis of DCS was based on the following criteria; 1) radiological evidence of CS or OPLL on X-ray films; 2) definite spinal cord compression on cervical magnetic resonance imaging (MRI); 3) neurological deficits in the upper extremities resulting from CS or OPLL; and 4) clinical and/or electrophysiological evidence of entrapment neuropathies in the upper extremities, namely carpal tunnel syndrome (CaTS), Guyon's tunnel syndrome (GTS), and/or cubital tunnel syndrome (CuTS). Pressure-provocative tests were used to confirm clinical entrapment neuropathies. Nerve conduction velocities were also examined. We found 28 patients with DCS (23 CS, 5 OPLL; 12.8% of all patients). There were 9 patients with clinical and electrophysiological DCS, 5 with clinical DCS, and 14 with electrophysiological DCS. Of the total number of patients with DCS, 21 proved to have CaTS, 4 had CuTS, 1 had GTS, 1 had both CaTS and CuTS, and 1 had both CaTS and GTS. Definite spinal cord compression was seen at C5/6 (23 patients), C4/5 (21), C3/4 (13) and C6/7 (10) on cervical MRI. In the majority of patients, neurological deficits of the upper extremities did not result from a single peripheral nerve lesion. It is well known that a discrepancy between neurological manifestation and neuro-imaging sometimes occurs in CS and OPLL, and circulatory disturbance in the spinal cord has been considered a possible pathogenetic mechanism of the disorder.(ABSTRACT TRUNCATED AT 250 WORDS)