Enriched Autologous Fat Grafting for Treating Pain at Amputation Sites

The objective of this pilot study is to assess the efficacy of minimally invasive autologous fat transfers at the amputation sites and the modulation of pain at the respective sites. Our investigators hypothesize that autologous fat grafting can provide a minimally invasive therapy to effectively mitigate pain syndromes at amputation sites, by introducing volume stable subcutaneous tissue over bony prominences and peripheral nerve trunks, thereby avoiding major surgical revisions and preserving limb length. The investigators further hypothesize that enriching the fat graft with autologous adipose stromal cells, a regenerative medicine approach, will lead to improved retention of the fat graft over time and result in a more favorable outcome. The Investigators will evaluate: 1. Treatment of painful amputation sites in 5 patients with fat grafting, intended to provide additional subcutaneous tissue padding over bony structures and nerve trunks. Limb anatomy and healing of the graft over time, along with stability/persistence of the new tissue, will be assessed by high resolution CT scanning with 3D reconstruction. Patients will be followed for 24 months after treatment to define long term outcomes. Patients will be enrolled who have pain at an amputation site that limits function and/or interferes with the ability to use a prosthesis. 2. Biologic properties of the cells within the fat graft and correlate with clinical outcomes. This will include adipose stem cell yield per volume of fat tissue, cell proliferation, capacity for adipogenic differentiation, lipolysis, and cell sub-population analysis by multiparameter flow cytometry. Results of these assays will be correlated with graft volume retention to search for predictors of good clinical outcome that are related to variation on adipose biology between subjects. 3. Quality of life measurements in patients before and after autologous fat grafting using validated psychosocial measures. This will include SF 36, the