Anatomo-physiological basis and applied techniques of electrical neuromodulation in chronic pain

Anatomo-physiological basis and applied techniques of electrical neuromodulation in chronic pain

Abstract

Chronic pain, a complex and debilitating condition, poses a significant challenge to both patients and healthcare providers worldwide. Conventional pharmacological interventions often prove inadequate in delivering satisfactory relief while carrying the risks of addiction and adverse reactions. In recent years, electric neuromodulation emerged as a promising alternative in chronic pain management. This method entails the precise administration of electrical stimulation to specific nerves or regions within the central nervous system to regulate pain signals. Through mechanisms that include the alteration of neural activity and the release of endogenous pain-relieving substances, electric neuromodulation can effectively alleviate pain and improve patients' quality of life. Several modalities of electric neuromodulation, with a different grade of invasiveness, provide tailored strategies to tackle various forms and origins of chronic pain. Through an exploration of the anatomical and physiological pathways of chronic pain, encompassing neurotransmitter involvement, this narrative review offers insights into electrical therapies' mechanisms of action, clinical utility, and future perspectives in chronic pain management.

Introduction

The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage." In twenty thirteen, the International Association for the Study of Pain established a task force to develop and update a classification of pain disorders. This effort led to the inclusion of a chronic pain classification in the twenty nineteen edition of the International Classification of Diseases, formally adopted by the World Health Organization. Chronic pain is defined by a duration of at least three months or beyond the usual healing period. It can be further categorized into nociceptive, neuropathic, and nociplastic pain types. Chronic pain presents a significant public health challenge, affecting millions of patients and incurring substantial medical expenses and lost productivity. According to the Global Burden of Disease Study, tension-type headache, migraine, low back pain, neck pain, diabetic neuropathy are among the most common and prevalent chronic pain syndromes in the population, increasing their years lived with disability.

In a certain percentage of patients, conventional treatments, including surgery, pharmacological therapies, combined with psychological, physical and occupational therapies, fail. In these patients, neuromodulation may have a role in treatment. Neuromodulation refers to a broad category of techniques or therapies that modulate the activity of the nervous system to achieve therapeutic effects through chemical interventions or electrical stimulation. Neurostimulation, which involve modifying or stimulating nerve activity through targeted electrical at specific neurological sites, is increasingly utilized in patients with chronic pain of varied origins. These modalities represent the evolving landscape for chronic pain management, each offering unique advantages and considerations.

This review aims to provide a comprehensive understanding of the neuroanatomy and neurophysiology of chronic pain, with an emphasis on the role of electrical neuromodulation in its treatment.