Implantable Wireless Brain-Computer Interface Systems in Patients With Tetraplegia

Inclusion Criteria: * Age ≥18 years and ≤65 years, male or female; * Tetraplegia due to C2-C5 cervical spinal cord injury, diagnosed per 2019 revised ISNCSCI of ASIA, injury grade A to B; * Intact cognitive function, MoCA-BLIND score ≥19; * Elbow flexor muscle strength ≤ Grade 3 by ISNCSCI; * Neurological assessment confirms normal motor cortex function without significant organic or functional brain lesions; * Tetraplegia diagnosed for ≥12 months, stable clinical status ≥6 months after standard treatment; * Good compliance, voluntary participation; informed consent signed by subject or legal representative. Exclusion Criteria: * Syringomyelia, severe neuralgia or spasticity limiting training participation; * Require tracheotomy, mechanical ventilation, nasogastric feeding to sustain vital functions; * High surgical risk: active systemic infection, coagulation disorders, antithrombotic therapy users; * Subjects implanted with CNS electrical stimulation medical devices; * Unstable medical conditions, severe mental/cognitive disorders confounding endpoint assessment; * Severe, unstable, uncontrolled complex regional pain syndrome; * Autoimmune-induced spinal cord dysfunction/injury; * History of stroke, multiple sclerosis, drug-resistant epilepsy, Alzheimer's Disease; * Peripheral neuropathy; * Pregnant/breastfeeding females, females planning pregnancy during trial; * Require MRI examinations during device implantation period; * Participated in other clinical trials within 1 month prior to enrollment; * Investigator judges participation unsafe, or subject unlikely to complete protocol follow-up.