|89th Annual Meeting Abstracts
Optimizing Craniofacial Microsomia and Rhomberg soft tissue reconstruction with fat grafting
James P. Bradley, M.D., Henry K. Kawamoto, Jr., MD, DDS, Alan Lim, MD, Derrick Wan, MD, Hurig V. Katchikian, BS.
University of California, Los Angeles, Los Angeles, CA, USA.
Purpose: For craniofacial deformities, skeletal reconstruction is often performed first, as a foundation for final soft tissue reconstruction or filling. As an alternative strategy, we studied serial fat grafting in both Craniofacial Microsomia (CM) and Rhomberg Syndrome (RS) patients. CM patients undergo multiple ear reconstructive and mandibular procedures and are ideal candidates for serial fat grafting. RS patients with progressive fat atrophy may have a theoretic problem with fat graft ‘take’. We also investigated laboratory tissue-engineering options to optimize fat graft survival.
1) For CM: We compared microvascular free flap soft tissue reconstruction to serial fat grafting.
2) For RS: We compared fat grafting in syndromic vs nonsyndrmic patients.
3) Laboratory Study: We compared human fat vs Adipose Derived Stem Cells (ASCs) vs genetically transected ASCs in a nude mouse.
Methods: Part I: Patients with moderate to severe CM were divided into two groups: Group 1) Microvascuar free flap (MVFF) reconstruction (parascapular or IMECS flap) or Group 2) Serial fat grafting (performed during multiple surgeries for mandible and ear reconstruction) (n=28). Outcomes were assessed with surface area scanning program and 3D photography volumetric analysis. Part II: RS fat grafting patients were compared to nonsydromic fat grafting patients for volume retention with similar methods as above (n=24). Part III: In a laboratory study we looked at fat graft survival after transfer to an immunocompromised mouse of 1) human fat cells, 2) ASCs, and 3) transfected (hoct4, hc-myc, hsox2, hklf4) ASCs (tASCs) to a more embryonic state, using histology at 4, 8, 12 weeks (n=30).
Results: Part I: Group 1 Free flap patients had a mean of 1.6 revisions following the original procedure; Group 2 Serial fat patients had a mean of 4.6 grafting procedures at the time of ear or mandibular reconstructions. Preop compared to follow-up: Group 1 showed a mean of 105cc volume fill and a final 135% surface area increase and 122% volume fill compared to the contralateral’unaffected’ side; Group 2 showed 33cc per case and a final 119% surface area increase and 95% volume fill compared to contralateral side. Part II: Rhomberg patients had a mean of 2.1 procedures with 55cc of fat grafted per procedure. Compared to nonsyndromic patients, the Rhomberg patients had slightly more loss of surface area (29% vs 18%) and volumetric fill (36% vs 22%) when 3-month images were compared to 1-year follow-up images. Part III: Laboratory harvested groups at all time-points showed better histologic fat graft survival with tASCs followed by ASCs followed by regular fat cells. VEGF gene expression in tASCs and ASCs was 5 times that of the regular fat cells.
1) For Craniofacial Microsomia patients with moderate to severe soft tissue hypoplasia, serial fat grafting provided a useful alternative avoiding the need for a microvascular free flap (parascapular/IMECS flap).
2) Rhomberg patients had less volume and surface area preservation compared to nonsyndromic patients, but fat transfer proved to still be a useful reconstructive tool.
3) Tissue engineering strategies, with ASCs or tASCs, offer improved fat survival in the laboratory.