Pilot Study of Vagal Stimulation in Chronic Low Back Pain

Overview

Low back pain is a major public health problem. It is the leading cause of disability in the world. The factors that lead to chronicity of low back pain are multi-factorial and are essentially represented by psychosocial factors (catastrophism, kinesiophobia, algophobia job dissatisfaction, emotional problems such as depression, anxiety, stress, injustice, etc.). Pain is a multimodal experience that involves different brain structures that are activated by the pain signal and involve the autonomic nervous system (ANS). The vagus nerve is the main actor of one of the two branches of the ANS, the parasympathetic system, which acts as a "slow-down". The vagus nerve participates in the inter-neuronal transmission of key neurotransmitters for mood, alertness, attention and motivation. Vagal stimulation has been used for many years as an analgesic device in chronic pain (vascular pain (facial vascular pain, fibromyalgia, visceral pain, gastrointestinal and pelvic pain...) To date, no study has been conducted on the value of vagal stimulation in chronic low back pain.

Low back pain is a major public health problem. It is the leading cause of disability in the world. The factors that lead to chronicity of low back pain are multifactorial, which explains the modest effectiveness of both drug treatments and multidisciplinary programs (analgesic drug interventions, non-pharmacological interventions with rehabilitation, physical exercise, psychotherapy, spinal ergonomics, meditation, yoga, etc.) in the treatment of low back pain. psychotherapy, spinal ergonomics, meditation, yoga...) in chronic forms. These factors of chronicization are essentially represented by psychosocial factors (catastrophism, kinesiophobia, algophobia, job dissatisfaction, emotional problems such as depression, anxiety stress, injustice...) In the chronic low back pain population, pain is a multimodal experience that involves different brain structures (insula, anterior cingulate cortex, amygdala and prefrontal cortex). These structures are activated by the pain signal and involve the autonomic nervous system (ANS). The vagus nerve is the main actor of one of the two branches of the ANS, the parasympathetic system, which acts as a "slow-down". The vagus nerve is involved in the inter-neuronal transmission of key neurotransmitters for mood, alertness, attention and motivation (serotonin, dopamine, oxytocin and noradrenaline). It is one of the longest nerves in the human body, originating from the base of the brain (nucleus tractus solitarius) and innervating most of the organs (heart, lung, stomach, liver, spleen, kidneys, gallbladder, pancreas, intestines). It allows the integration of information from the periphery (pain, stress, emotions), slows down the heart rate after a stress, reduces the caliber of the bronchial tubes to help breathing, reduces the inflammatory response, participates in digestion and in the communication with the digestive microbiota. Indeed, there seems to be an alteration of the vagal function in chronic pain patients patients: the vagus nerve is involved in the modulation of pain at different levels (medullary, cerebral) (medullary, cerebral) but also on the different components of pain (sensory, affective emotional, behavioral). The benefit of the stimulation of the vagus would be mediated by a modulation of afferent information (stress, pain, emotion) associated with a benefit of "relaxation" conveyed by the efferent fibers (cardiac, pulmonary effect...). This stimulation of the vagus nerve is done through an atrial electrode that stimulates the atrial branch of the vagus nerve. To date, no study has been conducted on the value of vagal stimulation in chronic low back pain. Because of the multifactorial mechanisms involved in this pathology, this type of therapy appears to be a useful complement to the management of our patients. This pilot study will allow us to evaluate the feasibility of a larger study with a placebo arm. The evaluation of tolerance and adherence to this therapy will be taken into account.