• Age 22-80 years old

• Clinical diagnosis of a refractory chronic pain syndrome including

∙ post-traumatic pain syndromes (e.g. root avulsions, nerve crush injuries, spinal cord injury)

‣ postsurgical pain syndromes (e.g., postmastectomy syndrome, post-thoracotomy syndrome, phantom limb pain, post-surgical spinal pain)

‣ postherpetic neuralgia

‣ complex regional pain syndrome

‣ atypical facial pain

‣ central pain syndromes (e.g. post-stroke pain, multiple sclerosis pain, post-radiation pain)

‣ post-radiation plexopathy

• Two or more years or more of medically refractory severe pain

• Average daily pain for the past 30 days reported as \>6 on a 0-10 numeric rating scale (NRS)

• Pain that fluctuates over a range of at least 3 points on the NRS

• Patient has failed at least two pain medications from different classes as determined by a neurologist or pain management specialist with stable doses of medications for 30 days prior to baseline visit.

• Lack of a surgically correctible etiology for the pain as determined by 2 independent surgeons

• Ability to speak / read English

• Capable of understanding and providing informed consent

⁃ Absence of significant cognitive impairment - score of 25 or greater on the Montreal Cognitive Assessment (MoCA)

⁃ Successful detection of pain biomarkers or positive symptomatic response to inpatient stimulation trial period if performed.