To evaluate the safety and efficacy of a Minimally Invasive Wireless Implantable Brain-Computer Interface (BCI) System NEO in patients with tetraplegia and to provide a basis for product registration.

Through brain-computer interface alternative technology, patients can control the external equipment with brain signals to improve the patient's quality of life.

Inclusion Criteria:

1. Age between 18 and 65 years old, no restriction on gender.
2. Tetraplegia caused by cervical spinal cord injury.
3. Score of ≤1 on either the ball grasp or water pouring tasks of the ARAT (Action Research Arm Test).
4. Muscle strength of finger flexors < grade 3 according to ISNCSCI (International Standards for Neurological Classification of Spinal Cord Injury).
5. Score of ≥2 for "hand to mouth" on ARAT; scores of ≥1 for both "hand to top of head" and "hand to behind the head."
6. Neurological assessment indicates normal function of the motor-related cortex, with no significant structural lesions or functional disorders identified.
7. Diagnosis confirmed for at least 12 months, with a stable condition for at least 6 months following standard treatment.
8. Normal cognitive function, good compliance, and voluntarily agrees to participate in the clinical trial.

Exclusion Criteria:

1. Without the consent of the patient or the patient's legal guardian.
2. Presence of syringomyelia, severe neuropathic pain, or severe spasticity that limits the participant's ability to engage in training.
3. Requires ventilator support.
4. Baclofen dosage >30 mg/day.
5. Received botulinum toxin injections in the upper limb, neck, or hand within 6 months prior to enrollment, or received stem cell therapy within 1 year.
6. High risk of surgical complications, such as active systemic infection, coagulation disorders (e.g., receiving anticoagulant therapy), or platelet count below 50,000.
7. Patients who have already been implanted with medical devices that deliver electrical energy to the central nervous system.
8. Any unstable or significant medical condition that may interfere with study procedures or confound the evaluation of study endpoints, such as depression, mood disorders, or other cognitive impairments.
9. Diagnosed with severe, unstable, and uncontrolled complex regional pain syndrome.
10. Autoimmune-mediated spinal cord dysfunction/injury.
11. History of other neurological disorders, such as stroke, multiple sclerosis, traumatic brain injury, or drug-resistant epilepsy.
12. Peripheral neuropathies (e.g. diabetic polyneuropathy, compressive neuropathies).
13. In the investigator's opinion, the study is unsafe or inappropriate for the participant, or the participant is unlikely to comply with the study follow-up schedule.