Neuropathic pain is one of the most debilitating forms of pain, resulting from damage or dysfunction in the somatosensory system. It affects 7-10% of the general population and is associated with serious consequences for the quality of life and daily functioning of patients. This pain is characterized by pathological mechanisms that lead to increased sensitivity to pain and to phenomena such as hypoesthesia, dysesthesia and paresthesia. Neuropathic pain does not subside after the damage is repaired and can become chronic, accompanied by emotional effects, such as anxiety, depression and sleep disorders. In these cases, where traditional pharmaceutical treatments fail, research interest has turned to other methods, such as repetitive transcranial magnetic stimulation (rTMS) (Tsai et al., 2023).
It should be noted that neuropathic pain is a real and intense experience, not to be considered “imaginary” or “subjective”.
What is Neuropathic Pain?
Neuropathic pain results from damage or dysfunction of the nerves that make up the peripheral or central nervous system. The source of the pain is not in the tissues that usually cause pain, but in the nervous system itself. This pain can occur without an external stimulus and is often characterized by a burning sensation, sharp pains, tingling, or abnormal sensations. Although the mechanisms of neuropathic pain are not fully understood, it is known to be associated with disturbances in pain processing by the brain and spinal cord (Bai et al., 2023).
Many pathological conditions can lead to neuropathic pain (Finnerup, Kuner & Jensen, 2021). The most common causes include:
- Diabetic Neuropathy: Caused by chronically high blood glucose, which leads to damage to the peripheral nerves.
- Postherpetic Neuralgia: Pain that persists after recovery from a herpes virus infection.
- Spinal Cord Injury: Can cause chronic pain in the extremities or trunk.
- Multiple Sclerosis: A neurological disease often associated with widespread neuropathic pain.
rTMS as a Treatment for Neuropathic Pain
rTMS is a non-invasive method that uses magnetic pulses to stimulates specific areas of the brain, mainly the primary motor area (M1). These pulses change the activity of neurons in these areas, resulting in the reorganization of the neural circuits responsible for the sensation of pain. Magnetic stimulation has been found to reduce neuronal hyperexcitability, which is associated with neuropathic pain (Bruno Daniel Carneiro & Tavares, 2024; Lefaucheur et al., 2020).
Clinical studies show that rTMS has positive effects in reducing neuropathic pain. In addition, patients also report an improvement in their emotional state, with a reduction in anxiety and depression. Typically, 5-10 sessions are required to achieve an analgesic effect, with pain improvement lasting up to months (Tsai et al., 2023). With repeated sessions, the interval can be extended more and more. The results of the treatment may vary depending on the pulse frequency, intensity and duration of the sessions (Bai et al., 2023).
rTMS is an innovative and promising treatment for the management of neuropathic pain. It offers hope of relief for patients who do not respond to pharmacological treatments, and the data so far indicate a significant analgesic effect.
Bibliography
Bai, Y.-W., Yang, Q.-H., Chen, P.-J. and Wang, X.-Q. (2023). Repetitive transcranial magnetic stimulation regulates neuroinflammation in neuropathic pain.Frontiers in immunology, 14. doi:https://doi.org/10.3389/fimmu.2023.1172293.
Bruno Daniel Carneiro and Tavares, I. (2024). Transcranial Magnetic Stimulation to Treat Neuropathic Pain: A Bibliometric Analysis.Healthcare, [online] 12(5), pp.555–555. doi:https://doi.org/10.3390/healthcare12050555.
Finnerup, N.B., Kuner, R. and Jensen, T.S. (2021). Neuropathic Pain: From Mechanisms to Treatment.Physiological Reviews, [online] 101(1), pp.259–301. doi:https://doi.org/10.1152/physrev.00045.2019.
Lefaucheur, J.-P., Aleman, A., Baeken, C., Benninger, D.H., Brunelin, J., Di Lazzaro, V., Filipović, S.R., Grefkes, C., Hasan, A., Hummel, F.C., Jääskeläinen, S.K., Langguth, B., Leocani, L., Londero, A., Nardone, R., Nguyen, J.-P. Nyffeler, T., Oliveira-Maia, A.J., Oliviero, A. and Padberg, F. (2020). Evidence-based guidelines on the therapeutic use of repetitive transcranial magnetic stimulation (rTMS): An update (2014–2018).Clinical Neurophysiology, 131(2), pp.474–528. doi:https://doi.org/10.1016/j.clinph.2019.11.002.
Tsai, Y.-Y., Wu, W.-T., Han, D.-S., Kamal Mezian, Ricci, V., Levent Özçakar, Hsu, P.-C. and Ke, C. (2023). Application of Repetitive Transcranial Magnetic Stimulation in Neuropathic Pain: A Narrative Review. 13(2), pp.258–258. doi:https://doi.org/10.3390/life13020258.
