AMP30: Autologous Fat Grafting, Amputation Sites Pain: Randomized

We hypothesize that autologous fat grafting can provide a minimally invasive therapy facilitated by enabling technology of specialized instrumentation to effectively mitigate pain syndromes at amputation sites, by introducing volume stable subcutaneous tissue over bony prominences and peripheral nerve trunks, thereby avoiding surgical revisions and preserving limb length. We further hypothesize that enriching the fat graft with autologous adipose stromal cells utilizing the Tissue Gensis Cell Isolation System (CIS), a regenerative medicine approach, will lead to improved retention of the fat graft over time and result in a more favorable outcome. Specific Aims: 1. Treat painful amputation sites in 30 patients with fat grafting 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. The primary outcome measures will be pain at the amputation site and improved ability to tolerate a prosthesis. Patients will be randomized to receive either standard fat grafting (15 patients)or cell enriched fat grafting (15 patients). 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. Assess 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. Measure quality of life in patients before and after autologous fat grafting using validated psychosocial measures. This will include, among other tools, SF 36, the Beck inventory, and instruments designed for assessing limb function. Study Design: Single center site, prospective, randomized, pilot outcomes study with treatment performed at the University of Pittsburgh. The primary outcome measurements will be: 1) fat graft retention at the amputation site; and 2) improved ability to tolerate a prosthetic device. This study will examine if fat grafting with cell enrichment using the Tissue Gensis Cell Isolation System, (CIS) will demonstrate increased fat retention and decreased pain compared to standard fat grafting alone. Clinical Impact: This study will significantly impact military trauma care by validating a minimally invasive cell based technique for alleviating pain at amputation sites and improving function with a prosthesis. Importantly, the goal will be reached without invasive surgery, increased risk, and a prolonged recovery. Given the high amputation rate in the current conflicts, this work is highly relevant to the care of the wounded warrior. A major goal of this study will be to transfer the techniques and knowledge gained to physicians throughout the Department of Defense healthcare system.