Utilizing pre-operative quantitative radiological imaging to predict surgical outcomes following untethering for adult tethered cord syndrome

Background Management of tethered cord syndrome (TCS) in adults remains controversial due to unpredictable surgical outcomes. This study aimed to evaluate quantitative MRI metrics—diffusional kurtosis imaging (DKI) and magnetization transfer ratio (MTR)—for predicting surgical outcomes in adult TCS patients. Methods Thirty-four adult TCS patients with tight/thickened/fatty filum underwent preoperative 3T MRI, including DKI and MT sequences. Patients with complex conditions were excluded. Clinical outcomes were mainly assessed by Japanese Orthopaedic Association (JOA) scores and bladder function. DKI parameters (mean/axial kurtosis: MK, KA) and MTR values at three levels at the end of the spinal cord were analyzed. Statistical methods included Spearman’s correlation, ROC analysis, and multivariate regression. Results Patients with recovery rate (RR) ≥ 50% (27/34) showed significantly lower KA (0.391 ± 0.017 vs. 0.434 ± 0.014, p < 0.001) and reduced MTR at upper spinal levels (MTR2: 52.411 ± 1.159 vs. 54.648 ± 1.254; MTR3: 52.523 ± 1.447 vs. 54.496 ± 1.049; p ≤ 0.003) compared to RR < 50% patients. KA and MTR3 independently correlated with RR (p < 0.001). ROC analysis confirmed KA and MTR3 as predictors for ≥ 50% RR (AUC: 0.971 and 0.873). Bladder improvement (12/21 patients) associated with higher preoperative KA (0.432 ± 0.013 vs. 0.393 ± 0.020, p < 0.001) but lacked independent predictors in regression. Conclusions Preoperative DKI and MTR of the lower spinal cord have prognostic value in assessing post-operative recovery in adult TSC patients. Advanced MRI imaging techniques may aid the decision-making process for these patients.