Motor Cortex Stimulation for Post-Stroke Thalamic Pain

The goal of this clinical trial is to investigate the mechanisms and predictive factors of motor cortex stimulation (MCS) for treating post-stroke thalamic pain, a challenging central neuropathic pain condition. Approximately 25% of patients show no short-term response to MCS, and about 20% experience long-term efficacy decay, yet the underlying analgesic mechanisms remain unclear and objective predictive biomarkers are lacking. This study aims to answer the following main questions: How does MCS modulate thalamic pain through the coordinated interaction of structural connectivity, functional network dynamics, and metabolic balance in the brain? What are the distinct neuroimaging characteristics that differentiate short-term non-responders, long-term responders, and those with long-term efficacy decay? Which multimodal imaging biomarkers can reliably predict short-term and long-term MCS efficacy? Participants will undergo a two-stage MCS surgical procedure. In stage I, epidural electrodes are implanted over the motor cortex, followed by a 2-week external trial stimulation. Participants who achieve a ≥50% reduction in Visual Analog Scale (VAS) pain score will proceed to stage II, receiving an implanted pulse generator for long-term stimulation. Those who do not respond in the short term will have the electrodes removed without undergoing stage II implantation. All participants will complete baseline clinical assessments and multimodal MRI scans (including T1, DTI, resting-state fMRI, and MRS) before surgery. Participants who receive the permanent implant will undergo follow-up clinical evaluations and repeat MRI scans at 3 and 6 months post-surgery. Researchers will compare imaging features across three outcome groups-short-term non-responders, long-term responders, and long-term decay group-to identify predictive biomarkers. Multimodal imaging data will be integrated using LASSO regression to build prediction models for both short-term screening and long-term efficacy warning. This research is expected to establish a "mechanism exploration - efficacy prediction - clinical decision" paradigm, providing objective imaging-based evidence to guide patient selection and postoperative management for MCS treatment.