Type-I collagen expression and ligamentum flavum hypertrophy in lumbar spinal stenosis patients: A systematic review

Background Lumbar spinal stenosis (LSS) is a degenerative condition marked by the narrowing of the lumbar spinal canal, resulting in nerve compression, lower back pain, and radiculopathy. Ligamentum flavum hypertrophy (LFH), a key contributor to LSS, is associated with increased type-I collagen expression. Despite advances in surgical techniques for LSS, there remains a paucity of comprehensive reviews synthesizing current evidence on the role of collagen type-I in LFH and its therapeutic potential. This systematic review examined the association between type-I collagen expression and LFH in LSS. Methods A literature search, conducted retrospectively through PubMed, Scopus, Cochrane Library, and Web of Science, identified studies examining type-I collagen expression in LSS. Six studies met the inclusion criteria. Data extraction focused on study design, sample characteristics, type-I collagen expression, and LFH outcomes. The risk of bias was evaluated using the ROBINS-I tool. Results All six studies identified a significant association between increased type-I collagen expression and LFH in patients with LSS. Elevated collagen I levels correlated with LF thickening, decreased elasticity, and fibrosis. Conclusions Although this systematic review highlights an association between increased collagen type-I expression and LFH in patients with LSS, the current evidence remains limited and heterogeneous. In addition, collagen type-I pathways might represent potential therapeutic targets, but further validation is required before a clinical trial.