Effect of linear polarized light irradiation near the stellate ganglion in skin blood flow of fingers in patients with progressive systemic sclerosis

Objective: The purpose of this study is to evaluate the effect of linear polarized light irradiation near the stellate ganglion area on cutaneous blood flow in fingers of patients with progressive systemic sclerosis. Background Data: Sympathetic overactivity is known to be present in patients with progressive systemic sclerosis. Recently introduced linear polarized light irradiation is designed to simulate noninvasive stellate ganglion block to decrease sympathetic output. Methods: Five patients with progressive systemic sclerosis and three normal healthy controls were studied. Linear polarized light (Super Lizer™) was irradiated near the stellate ganglion on the right side of the neck at 358 J/cm² for 10 min. Then, laser Doppler flowmetry, laser Doppler imager, and capillary microscopy were used to measure the cutaneous blood flow of the right fourth finger for 30 min. Results: No significant alternations of the skin blood flow between normal controls and patients with progressive systemic sclerosis after linear polarized light irradiation were detected. The effect of linear polarized light on the microcirculation of patients with progressive systemic sclerosis was minimal and transient. Conclusion: The effect of linear polarized light in treating patients with progressive systemic sclerosis may not result from the improvement of skin blood flow. Therefore, the use of linear polarized light in those patients to increase cutaneous blood flow should not be overemphasized.