Neurodegenerative diseases (NDs) represent a major global health challenge in aging populations, with their incidence continuing to rise worldwide. Although substantial progress has been made in elucidating the clinical features and molecular underpinnings of these disorders, the precise mechanisms driving neurodegeneration remain incompletely understood. This review examines the increasing significance of the gut–brain–immune triad in the pathogenesis of NDs, with particular attention to Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, and multiple sclerosis. It explores how disruptions in gut microbiota composition and function influence neuroinflammation, blood–brain barrier integrity, and immune modulation through microbial-derived metabolites, including short-chain fatty acids, lipopolysaccharides, and bacterial amyloids. In both Alzheimer’s and Parkinson’s diseases, a reduced abundance of short-chain fatty acid-producing bacterial taxa has been consistently associated with heightened pro-inflammatory signaling, thereby facilitating disease progression. Although detailed mechanistic understanding remains limited, experimental evidence—primarily from rodent models—indicates that microbial metabolites derived from a dysbiotic gut may initiate or aggravate central nervous system dysfunctions, such as neuroinflammation, synaptic dysregulation, neuronal degeneration, and disruptions in neurotransmitter signaling via vagal, humoral, and immune-mediated pathways. The review further highlights how gut microbiota alterations in amyotrophic lateral sclerosis and multiple sclerosis contribute to dysregulated T cell polarization, glial cell activation, and central nervous system inflammation, implicating microbial factors in disease pathophysiology. In addition to identifying critical knowledge gaps, the review emphasizes the need for sustained, multifactorial research efforts, including the development of physiologically relevant brain–gut organoid models and the implementation of standardized experimental protocols. A major limitation in the field remains the difficulty of establishing causality, as clinical manifestations often arise after extended preclinical phases—lasting years or decades—during which aging, dietary patterns, pharmacological exposures, environmental factors, and comorbidities collectively modulate the gut microbiome. Finally, the review discusses how microbial influences on host epigenetic regulation may offer innovative avenues for modulating neuroimmune dynamics, underscoring the therapeutic potential of targeted microbiome-based interventions in neurodegenerative diseases.

Chronic subdural hematoma (CSDH) is a common disease in neurosurgery, with epidemiological characteristics showing an overall annual incidence of 1.7–20.6 per 100,000 people and a higher prevalence in the elderly. However, despite the increased disease burden, there have been limited breakthroughs in treatment options over the past 20 years. A significant gap exists in our understanding of the exact pathophysiological mechanism of CSDH, leading to a lack of specific clinical treatment options based on a clear pathological mechanism. Current research suggests that the development of CSDH involves dual mechanisms of trauma and inflammation, and that these pathologic processes together promote pathological changes such as angiogenesis, inflammatory response, and neovascularization. Therapies for CSDH encompass both surgical (e.g., twist-drill drainage, burr-hole drainage, craniotomy) and non-surgical approaches (e.g., clinical observation, medication, intracranial pressure monitoring, anticoagulation). Meanwhile, middle meningeal artery embolization, as an emerging minimally invasive interventional technique, has shown good prospects for clinical application. This review aims to bridge the gap between current treatment options and the need for effective strategies by providing a comprehensive summary of the epidemiological trends, pathophysiological advances, and optimization of therapeutic strategies for CSDH.