Thoracic hypertrophied ligamentum flavum: A retrospective study of pre-operative factors and surgical outcome

Objectives: Thoracic hypertrophied ligamentum flavum (HLF) is a rare cause of thoracic myelopathy which requires surgical treatment. The study aims to analyze the pre-operative factors and surgical outcomes in patients with thoracic myelopathy secondary to HLF. Materials and Methods: This is a retrospective study of patients who underwent surgery for thoracic myelopathy due to HLF at a single center from December 2015 to November 2023. We included patient’s demographic data, clinical symptoms, radiological details, operative details, and outcome. We used Nurick’s grading system for outcome evaluation in pre-operative, post-operative, and follow-up. Relationship of various pre-operative parameters was evaluated with surgical outcomes on binary scale (favorable group [Nurick’s grade 1 and 2] and unfavorable outcome [Nurick’s grade 3–5]) using univariate and multivariate analysis. Results: A total of 57 patients were included in the study. On analyzing various prognostic factors with respect to favorable and unfavorable outcomes using univariate analysis, four factors came out to be statistically significant which were segments involved (multi vs. single segment involvement) ( P < 0.05), walking difficulty ( P < 0.05), intramedullary signal changes on T2-weighted magnetic resonance imaging (MRI) ( P < 0.001), and pre-operative Nurick’s grade ( P < 0.001). On multivariate analysis, only one factor, pre-operative Nurick’s grade came out statistically significant. Conclusion: Various factors are important in predicting the outcome of a patient with thoracic myelopathy secondary to HLF. The most important of which is pre-operative Nurick’s grade. Other factors that also affect the outcome are the presence of multisegmented disease and intramedullary T2 signal changes on MRI.