A Commentary on “The Gut-Disc Axis: Unraveling the Microbiome’s Role in Lumbar Disc Herniation”

Lumbar disc herniations (LDHs) are common conditions that cause lower back pain, nerve-related problems, and sometimes pain that radiates to the buttocks or legs.The pain usually occurs when the inner part of the disc, the nucleus pulposus, tears through the outer part, the annulus fibrosus.This further compresses the nerve root adjacent to the intervertebral disc (IVD), resulting in pain and numbness. 1The association between certain gut microbes and LDH is an emerging and very interesting topic in spine research.The debate over whether a disc herniation is caused solely by disc compression or by additional factors, such as microbial, immune, and metabolic factors, continues.Interestingly, Rajasekaran et al. 2 investigated 24 lumbar IVDs and found a distinct microbiome composition in healthy discs compared with degenerated and herniated discs.With this objective, Ambrosio et al. 3 conducted a systematic review very recently and followed PRISMA-ScR (Preferred Reporting Items for Systematic reviews and Meta-analyses extension for Scoping Reviews) guidelines.They started by identifying 876 articles from PubMed and Scopus, then included 26 studies for analysis, most of which were cross-sectional.To define the method of study, the authors used the SPIDER framework, where "S" stands for Sample, "PI" for Phenomenon of Interest, "D" for Design, "E" for Evaluation, and "R" for Research type.To avoid bias in this article, 2 reviewers independently selected the studies.A third reviewer was appointed to decide in case two of them did not agree whether the paper should be included or not.The strength of this article is its inclusion of research from 2006-2025, spanning almost 20 years.This brings together evidence from many countries, indicating that studying the gut-disc axis is important worldwide. 2,4,5The authors have systematically included studies from diverse groups, including human, animal, genetic, and metabolomic data, to propose the concept of the gut-disc axis.Additionally, the review article also discusses two important concepts.Firstly, the link between the gut microbiome and LDH, and secondly, the link between the local disc microbiome and LDH.Both topics are essential to understand separately to avoid any confusion between the inflammation caused by gut dysbiosis and the presence of the local disc microbiome.The review article also summarized preclinical studies suggesting that the microbiome is Neurospine