BACKGROUND:Ossification of the ligamentum flavum was previously considered to be rare in the population.As research has progressed,its incidence rate is increasing gradually,which has aroused the interest of a large number of researchers. OBJECTIVE:To visualize and analyze the research results on ossification of the ligamentum flavum from the Web of Science Core Collection since 1999 using bibliometric methods,and to review the research history of ossification of the ligamentum flavum,highlighting important literature,summarizing research hotspots,and providing ideas for researchers to find research directions. METHODS:Using the Web of Science Core Collection as the data source,relevant papers on ossification of the ligamentum flavum were searched and screened.VOSviewer 1.6.19 and CiteSpace 6.2.R6 were used to conduct the visual analysis of annual publication volume,research countries,institutions,citations,journals,authors,and keywords. RESULTS AND CONCLUSION:(1)A total of 347 papers were included.Since 1999,the number of published papers has increased in a spiral pattern.China's research started later than Japan's,but the number of publications has come up later,with Peking University being the institution with the most publications,and Prof.Chen Zhongqiang from Peking University being the scholar with the most publications.(2)Five of the 10 most frequently cited publications were related to the surgical treatment of the disease.(3)Excluding keywords directly related to the research topic and synthetically analyzing frequencies and betweenness centralities of key words,terms such as"thoracic myelopathy,""dural ossification,""minimally invasive surgery,"and"ossification of the posterior longitudinal ligament"occupied a central position in this field.(4)Keywords clustering analysis showed that clinical manifestations and surgical treatment of ossification of the ligamentum flavum accounted for a large proportion of study.(5)The timeline and burst analysis of keywords revealed that"minimally invasive surgery"appeared as a keyword around 2015,with the highest burst strength and the latest burst start time,and began to receive extensive attention from researchers in 2019.The burst of the keyword"dural ossification"has not yet ended.(6)Surgical treatment for ossification of the ligamentum flavum has been at the forefront of research.Development and research of minimally invasive surgery and research on dural ossification secondary to ossification of the ligamentum flavum are both current research hotspots and possible future research trends.