Safety and Efficacy of Autologous Human Schwann Cell (ahSC) Augmentation in Severe Peripheral Nerve Injury (PNI)

The primary purpose of this research study is to evaluate the safety and possible harms of injecting one's own Schwann cells along with nerve auto-graft after a severe injury to a major nerve has occurred.

Inclusion Criteria: 1. Persons with severe sciatic nerve injury, brachial plexus injury, and/or major nerve injury at the upper or lower extremity within previous year; 2. Between the ages of 18 and 65 at last birthday Exclusion Criteria: 1. Persons unable to safely undergo an MRI; 2. Persons with pre-existing conditions that would preclude satisfactory sural nerve harvest; 3. Persons with severe peripheral nerve injury gap length \> 10 cm; 4. Persons with history of radiation or local cancer in area of nerve injury, including primary tumors of the nerve; 5. Pregnant women or a positive pregnancy test in those women with reproductive potential prior to enrollment; 6. Presence of disease that might interfere with participant safety, compliance, or evaluation of the condition under study; 7. History of active substance abuse; 8. Persons allergic to gentamicin; 9. Persons who test positive for HIV or Hepatitis B or C virus. 10. Persons unable to provide consent independently due to cognitive impairment