Brain stimulation for chronic pain management: a narrative review of analgesic mechanisms and clinical evidence

Abstract

Chronic pain constitutes one of the most common chronic complaints that people experience. According to the International Association for the Study of Pain, chronic pain is defined as pain that persists or recurs longer than 3 months. Chronic pain has a significant impact on individuals’ well-being and psychosocial health and the economy of healthcare systems as well. Despite the availability of numerous therapeutic modalities, treatment of chronic pain can be challenging. Only about 30% of individuals with non-cancer chronic pain achieve improvement from standard pharmacological treatment. Therefore, numerous therapeutic approaches were proposed as a potential treatment for chronic pain including non-opioid pharmacological agents, nerve blocks, acupuncture, cannabidiol, stem cells, exosomes, and neurostimulation techniques. Although some neurostimulation methods such as spinal cord stimulation were successfully introduced into clinical practice as a therapy for chronic pain, the current evidence for brain stimulation efficacy in the treatment of chronic pain remains unclear. Hence, this narrative literature review aimed to give an up-to-date overview of brain stimulation methods, including deep brain stimulation, motor cortex stimulation, transcranial direct current stimulation, repetitive transcranial magnetic stimulation, cranial electrotherapy stimulation, and reduced impedance non-invasive cortical electrostimulation as a potential treatment for chronic pain.

Astroglial Cells: Emerging Therapeutic Targets in the Management of Traumatic Brain Injury

“…These methods encompass different mechanisms and stages of the condition. Several of them include: gene therapy, pharmacotherapy, neuroprotection, physical intervention, bioengineering, neurorehabilitation, or cell therapy that directly affects cells (including the astrocytes) [250][251][252][253]. The activity of astrocytes in the pathogenesis of traumatic spinal cord and brain injuries is being used as a basis for developing healing methods [149,254].…”

Non-invasive brain stimulation for fibromyalgia: current trends and future perspectives

“…In RINCE, electrodes attached to the patient’s scalp generate a specific current frequency, allowing the current to penetrate deeper into the cortex by reducing the impedance of the skin and skull ( O'Connell et al, 2018 ), potentially leading to improved stimulation effects. There are limited reports on RINCE therapy, and its adverse effects include transient mild head discomfort and localized cutaneous reactions ( Szymoniuk et al, 2023 ). In an RCT investigating RINCE therapy for fibromyalgia control, it was found that mean pressure points and pressure pain thresholds improved in the active treatment group compared to the sham treatment group ( Hargrove et al, 2012 ).…”

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

“…Deep Brain Stimulation (DBS) consists in the surgical implantation of thin electrodes within specific area of the brain to be stimulated. In case of chronic pain, electrodes are generally positioned in the PAG, in the periventricular gray matter, the ventralposterior medial or the ventral posterior lateral nuclei of the thalamus (contralateral to the side of pain), the anterior cingulate cortex or the posterior insula [ 75 , 76 ]. The positioning generally required a frame-based or frame-less stereotactic technique, targeting the area with a magnetic resonance imaging on the day before surgery and, in some centers, with intraoperative microelectrode recordings.…”