Mechanisms of Action of Dorsal Root Ganglion Stimulation.

The dorsal root ganglion (DRG) serves as a pivotal site for managing chronic pain through dorsal root ganglion stimulation (DRG-S). In recent years, the DRG-S has emerged as an attractive modality in the armamentarium of neuromodulation therapy due to its accessibility and efficacy in alleviating chronic pain refractory to conventional treatments. Despite its therapeutic advantages, the precise mechanisms underlying DRG-S-induced analgesia remain elusive, attributed in part to the diverse sensory neuron population within the DRG and its modulation of both peripheral and central sensory processing pathways. Emerging evidence suggests that DRG-S may alleviate pain by several mechanisms, including the reduction of nociceptive signals at the T-junction of sensory neurons, modulation of pain gating pathways within the dorsal horn, and regulation of neuronal excitability within the DRG itself. However, elucidating the full extent of DRG-S mechanisms necessitates further exploration, particularly regarding its supraspinal effects and its interactions with cognitive and affective networks. Understanding these mechanisms is crucial for optimizing neurostimulation technologies and improving clinical outcomes of DRG-S for chronic pain management. This review provides a comprehensive overview of the DRG anatomy, mechanisms of action of the DRG-S, and its significance in neuromodulation therapy for chronic pain.

Catecholaminergic Polymorphic Ventricular Tachycardia: Clinical Characteristics, Diagnostic Evaluation and Therapeutic Strategies.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a severe hereditary arrhythmia syndrome predominantly affecting children and young adults. It manifests through bidirectional or polymorphic ventricular arrhythmia, often culminating in syncope triggered by physical exertion or emotional stress which can lead to sudden cardiac death. Most cases stem from mutations in the gene responsible for encoding the cardiac ryanodine receptor (RyR2), or in the Calsequestrin 2 gene (CASQ2), disrupting the handling of calcium ions within the cardiac myocyte sarcoplasmic reticulum. Diagnosing CPVT typically involves unmasking the arrhythmia through exercise stress testing. This diagnosis emerges in the absence of structural heart disease by cardiac imaging and with a normal baseline electrocardiogram. Traditional first-line treatment primarily involves ß-blocker therapy, significantly reducing CPVT-associated mortality. Adjunctive therapies such as moderate exercise training, flecainide, left cardiac sympathetic denervation and implantable cardioverter-defibrillators have been utilized with reasonable success. However, the spectrum of options for managing CPVT has expanded over time, demonstrating decreased rates of arrhythmic events. Furthermore, ongoing research into potential new therapies including gene therapies has the potential to further enhance treatment paradigms. This review aims to succinctly encapsulate the contemporary understanding of the clinical characteristics, diagnostic approach, established therapeutic interventions and the promising future directions in managing CPVT.

Evidence-Based Clinical Practice Guidelines on Regenerative Medicine Treatment for Chronic Pain: A Consensus Report from a Multispecialty Working Group.

Purpose: Injectable biologics have not only been described and developed to treat dermal wounds, cardiovascular disease, and cancer, but have also been reported to treat chronic pain conditions. Despite emerging evidence supporting regenerative medicine therapy for pain, many aspects remain controversial. Methods: The American Society of Pain and Neuroscience (ASPN) identified the educational need for an evidence-based guideline on regenerative medicine therapy for chronic pain. The executive board nominated experts spanning multiple specialties including anesthesiology, physical medicine and rehabilitation, and sports medicine based on expertise, publications, research, and clinical practice. A steering committee selected preliminary questions, which were reviewed and refined. Evidence was appraised using the United States Preventive Services Task Force (USPSTF) criteria for evidence level and degree of recommendation. Using a modified Delphi approach, consensus points were distributed to all collaborators and each collaborator voted on each point. If collaborators provided a decision of "disagree" or "abstain", they were invited to provide a rationale in a non-blinded fashion to the committee chair, who incorporated the respective comments and distributed revised versions to the committee until consensus was achieved. Results: Sixteen questions were selected for guideline development. Questions that were addressed included type of injectable biologics and mechanism, evidence in treating chronic pain indications (eg, tendinopathy, muscular pathology, osteoarthritis, intervertebral disc disease, neuropathic pain), role in surgical augmentation, dosing, comparative efficacy between injectable biologics, peri-procedural practices to optimize therapeutic response and quality of injectate, federal regulations, and complications with mitigating strategies. Conclusion: In well-selected individuals with certain chronic pain indications, use of injectable biologics may provide superior analgesia, functionality, and/or quality of life compared to conventional medical management or placebo. Future high-quality randomized clinical trials are warranted with implementation of minimum reporting standards, standardization of preparation protocols, investigation of dose-response associations, and comparative analysis between different injectable biologics.