Spinal Cord Stimulation for Poststroke Spasticity

The goal of this clinical trial is to learn whether spinal cord stimulation (SCS) is effective in treating post-stroke spasticity in adults. It will also evaluate the safety of the implanted SCS system. The main questions it aims to answer are: 1. Does active SCS reduce limb spasticity compared with sham stimulation? 2. What device-related problems do participants experience during the study? All participants receive the same implantation and programming procedures,but no therapeutic stimulation(0 mA) for sham SCS group duringthe first 6 weeks after randomization. Participants will: 1. Have an SCS system surgically implanted 2. Be randomly assigned to receive active SCS or sham SCS for 6 weeks 3. After completion of the 6-week randomized comparison period, active stimulation will be initiated for all participants. 4. Attend a post-operative visit within 3 to 7 days after surgery for device activation or sham activation, programming, safety checks, and study assessments 5. Attend follow-up visits for study assessments at approximately 6, 12, 24 weeks, 1 year and 2 years after randomization 6. Complete assessments of muscle spasticity, joint range of motion, motor function, walking ability, daily functioning, pain, and quality of life 7. Report any medical problems or device-related problems during the study