ISASS Recommendations and Coverage Criteria for Restorative Neurostimulation for Multifidus Dysfunction, Lumbar Region: Coverage Indications, Limitations, and/or Medical Necessity—An ISASS 2025 Guideline Update

Patients suffering from chronic mechanical low back pain secondary to multifidus dysfunction represent a unique and increasingly recognized subset of the overall chronic mechanical low back pain population. Neuromuscular inhibition and fatty infiltration of the dysfunctional multifidus muscle contribute to persistent pain, spinal instability, and disability that fail to resolve with conventional therapy. As of October 2024, the introduction of the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) code M62.85 provides formal classification of this disease entity and allows providers to diagnose this condition with a higher level of specificity. Permanently implanted restorative neurostimulation systems, of which the ReActiv8 device (Mainstay Medical) is currently the only US Food and Drug Administration (FDA)-approved technology (FDA Product Code QLK), directly target chronic low back pain associated with lumbar multifidus dysfunction to treat the underlying condition. This 2025 International Society for the Advancement of Spine Surgery guideline update (1) summarizes the high-quality clinical data supporting long-term efficacy and safety of restorative neurostimulation, including longitudinal outcomes from a 5-year pivotal study, randomized controlled trials, and other clinical studies, (2) updates all coding guidance to reflect current ICD-10 and FDA device status, and (3) reports on payer trends, including the recent positive Anthem Blue Cross Blue Shield coverage decision. The International Society for the Advancement of Spine Surgery reaffirms its support for coverage of implantable restorative neurostimulation by payers in appropriately selected patients, consistent with the demonstrated evidence.