Narrative review of current neuromodulation modalities for spinal cord injury

Abstract

Neuromodulation is a developing field of medicine that includes a vast array of minimally invasive and non-invasive therapies including transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), vagus nerve stimulation (VNS), peripheral nerve stimulation, and spinal cord stimulation (SCS). Although the current literature surrounding the use of neuromodulation in managing chronic pain is abundant, there is an insufficient amount of evidence specifically regarding neuromodulation in patients with spinal cord injury (SCI). Given the pain and functional deficits that these patients face, that are not amenable to other forms conservative therapy, the purpose of this narrative review is to examine and assess the use of various neuromodulation modalities to manage pain and restore function in the SCI population. Currently, high-frequency spinal cord stimulation (HF-SCS) and burst spinal cord stimulation (B-SCS) have been shown to have the most promising effect in improving pain intensity and frequency. Additionally, dorsal root ganglion stimulation (DRG-S) and TMS have been shown to effectively increase motor responses and improve limb strength. Although these modalities carry the potential to enhance overall functionality and improve a patient's degree of disability, there is a lack of long-term, randomized-controlled trials in the current space. Additional research is warranted to further support the clinical use of these emerging modalities to provide improved pain management, increased level of function, and ultimately an overall better quality of life in the SCI population.

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“…In the field of chronic pain, the need for new, effective treatment options is particularly high, since many pain patients have exhausted the standard treatment methods without having achieved a significant improvement in their symptoms. It is postulated that the analgesic effect is achieved through the property of tDCS to influence neuronal activity by polarizing the resting membrane ( 9 , 32 ). Clinical applications of tDCS were investigated in randomized controlled studies, such as the treatment of migraine patients.…”

“…There are only a few studies investigating the effectiveness of tDCS in spinal cord injury. In this field, TMS appears to be superior to DCS when applied transcranially ( 9 ). However, there is increasing evidence that the therapeutic efficacy of DCS becomes more promising when the method is applied transcutaneously in the affected region of the spinal cord.…”

“…Currently, neuromodulation is a fast-growing field of mostly non-invasive therapies, which includes, in addition to SCS and tDCS, vagus nerve stimulation (VNS), peripheral nerve stimulation, transcranial magnetic stimulation (TMS) and transcutaneous spinal direct current stimulation (tsDCS) ( 9 ). The latter is a non-invasive method – like tDCS—using constant currents through electrodes which are directly applied to the skin via a dermal patch instead of applying a pulse stimulation through epidural electrodes as is it the case in SCS ( 10 ).…”

Neuromodulation and the Gut-Brain Axis: Therapeutic Mechanisms and Implications for Gastrointestinal and Neurological Disorders

“…Various neuromodulation modalities can be categorized according to their specific targets and methods of influencing the neurological system [3]. The aforementioned categories include Deep Brain Stimulation (DBS), Vagus Nerve Stimulation (VNS), Spinal Cord Stimulation (SCS), and Transcranial Magnetic Stimulation (TMS) [54]. DBS encompasses a surgical procedure wherein a device is implanted to administer targeted electrical impulses to distinct regions of the brain.…”

Neuromodulation and the Gut–Brain Axis: Therapeutic Mechanisms and Implications for Gastrointestinal and Neurological Disorders

“…Different types of neuromodulation techniques are distinguished by their unique targets and methods of affecting the neurological system [ 4 ]. The aforementioned categories include deep brain stimulation (DBS), vagus nerve stimulation (VNS), Spinal Cord Stimulation (SCS), and Transcranial Magnetic Stimulation (TMS) [ 5 ]. DBS encompasses a surgical procedure wherein a device is implanted to administer targeted electrical impulses to distinct regions of the brain.…”