Pathophysiology of Post Amputation Pain

Inclusion Criteria:

1. At least 18 years old
2. Able to read and speak English and provide informed consent
3. Single Amputation, upper or lower.
4. Subject has chronic post amputation pain lasting longer than three months
5. Subject has healed amputation wounds
6. Pain must be ≥3 on a scale of 0-10, 0 being no pain, 10 being the worse pain imaginable.
7. If subjects pain is non-existent during fMRI scans, the subject needs to be willing to have their pain induced by targeting pain trigger points (for example, study's postdoctoral fellow would massage certain regions of the affected limb to trigger PAP).
8. Subject agrees to 1) Stop taking all aspirin seven days prior to their second visit (Bayer,Ecotrin,Alka Seltzer, etc.) 2) All inflammatory medications 48 hours prior to their second visit (Advil, Motrin, Indocin, Lodine , Ibuprofen, Aleve, Naproxen, etc. 3) Supplements such as Vitamin E and Fish Oil 48 hours prior to their second visit.
9. Subject agrees to continue other prescribed medications.
10. Subject is willing to have hypodermic needle injections and images taken of them (digital, thermal, and fMRI).
11. Able to understand and comply with all data collection methodology including electronic diary.
12. If female, is not pregnant and not currently attempting to conceive; if of childbearing potential, use of a highly effective method of birth control (as determined by Pl).

Exclusion Criteria:

1. Subject is allergic to Isovue 300 or amide-type local anesthetics such as bupivicaine, lidocaine, or mepivacaine.
2. Subject has a diagnosis of bleeding diathesis or an immune compromise.
3. Subject has pain that is more severe than their post amputation pain.
4. Subject has a clinical diagnosis of fibromyalgia.
5. Subject has metal shavings and or is frequently in an environment where there is metal work being done or significant amounts of metal shavings.
6. Subject has ferrous metal implants, aneurism clips, bioelectric devices, and other implants which can be affected by the magnetic field of the MRI.
7. Subject is claustrophobic.
8. Subject weighs more than 300 pounds.
9. Subject plans to start new pain treatments or therapies during the study (e.g. new pain medication, injections, PT, surgery).