Decreased sympathetic outflow to muscles in patients with cervical spondylosis

To clarify the pathogenesis of neurologic symptoms of a vascular nature that may accompany cervical spondylosis (CS), we measured the sympathetic outflow to muscles (muscle sympathetic nerve activity: MSNA) in 8 ambulatory patients with CS and 10 healthy volunteers (controls). The burst rate and incidence of MSNA at rest were significantly lower in patients with CS than in controls (P< 0.01). There were no differences between the 2 groups in either resting heart rate or blood pressure. During a head-up tilting, the changes in MSNA were slightly greater in CS patients than controls due to reduced baseline levels of MSNA in CS patients. The burst incidence of MSNA in CS was significantly negatively correlated with the severity of pyramidal tract symptoms (P< 0.05). The decreased MSNA at rest in CS patients may be due to spinal cord compression resulting from posterior spondylotic changes in the cervical spine.