Clinical characterization of tethered cord syndrome due to lipomatous filum and filum terminale lipoma in symptomatic children

OBJECTIVE: Tethered cord syndrome (TCS) is heterogeneous, and a filum with lipomatous tissue can present in multiple patterns. The aim of this study was to determine whether filum characteristics are associated with particular symptomatology. METHODS: A descriptive cross-sectional retrospective study was conducted over 2 years (2023-2025) at a single institution. Patients with TCS and filum with lipomatous tissue were evaluated using 24 TCS-related variables and 10 filum-related variables. Statistical methods included using the chi-square test and ANOVA for frequency differences, multivariable logistic regression with odds ratios, and statistical weight analysis. RESULTS: Sixty-eight patients (35 male, mean age 9.01 years) were included in the analysis. A significantly younger age at diagnosis was seen in patients with proximal lipomatous tissue (mean 4.67 ± 3.90 years), lipomatous tissue > 3 cm (mean 7.07 ± 3.17 years), conus medullaris below L2 (mean 6.43 ± 3.74 years), and syrinx (mean 5.42 ± 3.03 years). Vesicourethral dyssynergia was more frequent in patients with filar lipoma versus lipomatous filum (58.3% vs 26.8%), those with complete conus versus caudal regression (63.6% vs 26.3%), and those with vertebral dysraphism versus without (44.4% vs 18.8%). In the multivariate analysis, smaller total lipomatous tissue was associated with less overactive bladder (OR 0.04 and 0.044). Conus medullaris below L2 (OR 31.5) and proximal lipomatous tissue (OR 18.1) were related to underactive bladder. Proximal lipomatous tissue (OR 26.2) and low-lying conus (OR 9.8) were associated with high-risk neurogenic bladder. Lipomatous filum < 1 cm was associated with idiopathic scoliosis (OR 3.25). Distal lipomatous tissue interactions such as filum ≤ roots with distal lipomatous tissue (OR 121.20), dural adhesion with distal lipomatous tissue (OR 43.90), and yin-yang signal pattern with distal lipomatous tissue (OR 19.40) were associated with foot deformities. The yin-yang signal intensity pattern on MRI and vertebral dysraphism (OR 5.8) increased the likelihood of moderate-to-severe sciatic pain. CONCLUSIONS: Filum patterns were associated with features of TCS, supporting classification of the filum based on lipomatous tissue.