The Link Between Spinal Cord Stimulation and the Parasympathetic Nervous System in Patients With Failed Back Surgery Syndrome.

OBJECTIVES In patients with chronic pain, a relative lower parasympathetic activity is suggested based on heart rate variability measurements. It is hypothesized that spinal cord stimulation (SCS) is able to influence the autonomic nervous system. The aim of this study is to further explore the influence of SCS on the autonomic nervous system by evaluating whether SCS is able to influence skin conductance, blood volume pulse, heart rate, and respiration rate. MATERIALS AND METHODS Twenty-eight patients with Failed Back Surgery Syndrome (FBSS), who are treated with SCS, took part in this multicenter study. Skin conductance and cardiorespiratory parameters (blood volume pulse, heart rate, and respiration rate) were measured during on and off states of SCS. Paired statistics were performed on a 5-min recording segment for all parameters. RESULTS SCS significantly decreased back and leg pain intensity scores in patients with FBSS. Skin conductance level and blood volume pulse were not altered between on and off states of SCS. Heart rate and respiration rate significantly decreased when SCS was activated. CONCLUSIONS Parameters that are regulated by the sympathetic nervous system were not significantly different between SCS on and off states, leading to the hypothesis that SCS is capable of restoring the dysregulation of the autonomic nervous system by primarily increasing the activity of the parasympathetic system, in patients with FBSS.