Inclusion Criteria:

• Age ≥ 18 years old.
• Neuropathic pain of the upper limb ≥ 3 months following brachial plexus avulsion injury.
• Patients must be planned to undergo trial of high-frequency spinal cord stimulation for the treatment of chronic neuropathic pain due to brachial plexus avulsion injury.

Exclusion Criteria: 

• Pregnant at the time of consideration for trial and/or implant per patient report.
• Active substance use disorder of any kind.
• Active tobacco use.
• Use of moderate or high dose opioid medication (oral morphine equivalents >100 mg daily).
• Active, untreated major psychiatric disorder that might interfere with subject’s ability to participate.
• Involvement in active litigation related to injury per patient report.
• Patient has not undergone conservative medical management for at least 3 months (including physical and/or occupational therapy and at least one trial of neuropathic pain medication).