Vagus nerve stimulation as a novel therapeutic approach for musculoskeletal diseases.

Vagus nerve stimulation (VNS) has gained significant attention as a therapy for various medical conditions due to its ability to modulate chronic diseases, pain, and inflammation. VNS delivered by an implanted device is FDA approved for severe epilepsy and refractory depression. VNS delivered with implantable devices or transcutaneous methods are now being studied in several musculoskeletal diseases including osteoarthritis, rheumatoid arthritis, systemic lupus erythematosus, and fibromyalgia. VNS activates the neuroimmune axis including the cholinergic anti-inflammatory pathway (CAP), suppressing inflammation and reducing pain. Here, we review the pathophysiology of VNS and the outcomes from clinical trials in musculoskeletal diseases. We address the limitations of these studies, including the inconsistent use of physiological biomarkers, such as heart rate variability, to ensure that VNS is engaging the vagus nerve. More studies are required to reveal the full potential of VNS for pain reduction and disease modification.