Comprehensive analysis of the pathology of the filum terminale in tethered cord syndrome from a microscopic perspective

Li Yulong; Yang Jichao; Ji Shanfeng; Gu Haoyuan; Ma Huidi; Lou Yongli

doi:10.11850/j.issn.1009-122X.2025.02.007

Abstract：Objective To investigate the etiology and pathogenesis of tethered cord syndrome(TCS).Methods The clinical data of 20 patients with TCS were analyzed retrospectively,all of whom were treated by surgery,and the relevant pathological treatment of the surgically resected filum terminal was performed,and microscopic observation was performed under light microscope and electron microscope.Results Hematoxylin-eosin staining showed that irregular thickening,disorganized arrangement,and disordered direction of collagen fibers in the filum terminale of TCS,along with the presence of neural tissue and fatty infiltration.MASSON staining demonstrated significant fibrosis of TCS filum terminale and an increase in small blood vessels.Reticular fiber staining showed a reduction and sparse arrangement of reticular fibers.Resorcin-fuchsin staining indicated a decrease in elastic fibers.Scanning electron microscopy(SEM)revealed thickened and disorganized collagen fibers with abnormal adhesion and fusion,as well as the deposition of crystalline substances.Elastic fibers were observed parallel to collagen fibers,with reticular fibers connecting the two.Transmission electron microscopy(TEM)showed collagen fibers in cross-section with halos of varying diameters,while longitudinal sections displayed the disappearance of periodic striations and disorganized arrangement.Additionally,vascular endothelial cells and fibroblasts were observed.Conclusion The primary causes of reduced elasticity and increased tension in the filum terminale of TCS patients are the abnormal proliferation of non-elastic components such as collagen fibers and adipocytes,as well as the reduction of elastic and reticular fibers.