Evaluate the characteristics and clinical significance of “toxic twin-leaf” sign in spinal epidural metastases before percutaneous vertebroplasty

OBJECTIVE: Our study aimed to analyze morphological features of spinal epidural metastases using magnetic resonance imaging (MRI) and investigate the formation mechanism and clinical significance of the “toxic twin-leaf” sign in spinal epidural metastasis. MATERIALS AND METHODS: We retrospectively studied 108 patients with spinal epidural metastases who underwent MRI. Patients were divided into “toxic twin-leaf” sign group (group A) and irregular group (group B). Chi-square test was used to analyze data on sex, vertebra location, presence of fracture in the corresponding vertebral body, involvement of the corresponding pedicle, and the primary tumor. Further, group data were analyzed using the rank sum test; p ​< ​0.05 was considered significant. RESULTS: The “twin-leaf” sign was noted in 88 cases with 136 epidural masses and 20 cases of irregular shape in 108 patients; the “toxic twin-leaf” sign accounted for 87.18% of spinal epidural metastases. A difference between groups in the vertebra location (p ​< ​0.01) was observed, but no differences were found in sex, presence of fractures in the corresponding vertebral body, involvement of the corresponding pedicle, and primary tumor (p ​> ​0.05). Intergroup differences in the rate of spinal stenosis on axial and sagittal images were significant. CONCLUSIONS: MRI axial sequences clearly revealed the morphology of spinal epidural metastases. Detection of the “toxic twin-leaf” sign in spinal epidural metastases was of great clinical significance. Furthermore, determining the degree of spinal stenosis in the axial sequence provided a more accurate evaluation of patients’ condition compared to the sagittal sequence.