Restoring upper extremity function in patients with cervical spinal cord injury is extremely important for patients' independence and quality of life.

At present, there are limited options for hand or arm reanimation in this patient population. Nerve transfer is one such option that can partially restore the natural movement of hand or arm function in select patients.

The investigators are interested in understanding whether recovery of hand or arm motor function after nerve transfer can be augmented by cervical epidural spinal cord stimulation.

The study will enroll up to 20 participants in a single arm prospective clinical study. Potential participants will have already had a nerve transfer surgery more than 6 months prior to enrollment and will have also completed post-nerve transfer physical /occupational neurorehabilitation.

At baseline, upper extremity muscle strength, muscle force and nerve health with needle electromyography and neuroimaging will be tested.

Patients will undergo percutaneous (temporary) spinal cord stimulator leads placement in the cervical supralesional spine region.

Week 0-4: Weekly testing of motor function and muscle contraction force with the stimulation turned on versus turned off will be performed. Stimulation parameters for each target upper extremity muscle will also be documented.

Temporary leads will be removed after approximately 4 weeks.

At the last research visit at approximately 6-7 weeks post leads placement muscle strength/force will be assessed to determine the duration of the stimulation effect (if it is sustained). To assess any improvement of nerve health, neuroimaging and electromyography will also be performed.

Inclusion Criteria:

• Age ≥18 years and ≤65
• Provides informed consent
• History of upper extremity nerve transfer > 6 months prior to enrollment
• Completion of standard post-nerve transfer occupational therapy
• Baseline upper extremity strength of < 5/5 grade with the MRC
• Scheduled to undergo a cervical spinal cord stimulation procedure for chronic pain refractory to first line therapy
• Willing and able to adhere to the study protocol

Exclusion Criteria:

• Central nervous system (CNS) malignancy
• A contraindication to the SCS procedure
• Diagnosis that precludes the patient from full participation in the protocol
• A functional implanted device (pacemaker, vagus nerve device, baclofen pump)
• Botulinum toxin injection in upper extremity muscles < 6 months prior to enrollment
• For female participants, current/planned pregnancy (females of childbearing age will be asked to take a pregnancy test on the day of the intervention)
• Other factors that prevent participation in the opinion of the surgeon-principal investigator

Individual participant data will not be shared with researchers outside of the study, except as required de-identified data for publication purposes.