Central Neuropathic Mechanisms in Pain Signaling Pathways: Current Evidence and Recommendations.

Omar Viswanath, Ivan Urits, James Burns, Karina Charipova, Kyle Gress, Alexandra McNally, Richard D Urman, Ali Welschmeyer, Amnon A Berger, Hisham Kassem, Manuel G Sanchez, Alan D Kaye, Treniece N Eubanks, Elyse M Cornett, Anh L Ngo

Journal: Advances in therapy 2020;37(5):1946-1959

PMID: 32291648

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Abstract

PURPOSE

This is a comprehensive review of the current literature on central neuropathic pain mechanisms that is secondary to spinal cord injury. It reviews recent and seminal findings on the pathophysiology, diagnosis, and treatment and compares treatment options and recommendations.

RECENT FINDINGS

Neuropathic pain (NP) is a common complication of spinal cord injury (SCI). Chronicity of NP is attributed to increased abundance of inflammatory mediators and ion channel dysfunction leading to afferent nerve sensitization; nerve damage and nerve-glia cross talk have also been implicated. Conventional treatment is medical and has had limited success. Recent studies have made headway in identifying novel biomarkers, including microRNA and psychosocial attributes that can predict progress from SCI to chronic NP (CNP). Recent advances have provided evidence of efficacy for two promising drugs. Baclofen was able to provide good, long-lasting pain relief. Ziconotide, a voltage-gated calcium channel blocker, was studied in a small trial and was able to provide good analgesia in most participants. However, several participants had to be withdrawn because of worrisome creatine phosphokinase (CPK) elevations, and further studies are required to define its safety profile. Non-medical interventions include brain sensitization and biofeedback techniques. These methods have recently had encouraging results, albeit preliminary. Case reports of non-conventional techniques, such as hypnosis, were also reported. CNP is a common complication of SCI and is a prevalent disorder with significant morbidity and disability. Conventional medical treatment is limited in efficacy. Recent studies identified baclofen and ziconotide as possible new therapies, alongside non-medical interventions. Further research into the pathophysiology is required to identify further therapy candidates. A multidisciplinary approach, including psychosocial support, medical and non-medical interventions, is likely needed to achieve therapeutic effects in this difficult to treat syndrome.

Address: Valley Anesthesiology and Pain Consultants-Envision Physician Services, Phoenix, AZ, USA.; Department of Anesthesiology, University of Arizona College of Medicine Phoenix, Phoenix, AZ, USA.; Department of Anesthesiology, Creighton University School of Medicine, Omaha, NE, USA.; Beth Israel Deaconess Medical Center, Department of Anesthesiology, Critical Care, and Pain Medicine, Harvard Medical School, Boston, MA, USA. [email protected].; Georgetown University School of Medicine, Washington, DC, USA.; Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, MA, USA.; Beth Israel Deaconess Medical Center, Department of Anesthesiology, Critical Care, and Pain Medicine, Harvard Medical School, Boston, MA, USA.; Department of Anesthesiology, Mount Sinai Medical Center, Miami Beach, FL, USA.; Department of Pain Medicine, Pain Specialty Group, Newington, NH, USA.; Department of Anesthesiology, Louisiana State University Health Shreveport, Shreveport, LA, USA.; Department of Pain Medicine, Pain Specialty Group, Newington, NH, USA.; Harvard Medical School, Boston, USA.

DOI: 10.1007/s12325-020-01334-w