Reply: Prospective Randomized Comparison of Scar Appearances between Cograft of Acellular Dermal Matrix with Autologous Split-Thickness Skin and Autologous Split-Thickness Skin Graft Alone for Full-Thickness Skin Defects of the Extremities.

Abstract

Sir: We would like to thank Yu and Qi for their interest in and comments on our article. We note they welcomed the described protocol of single-stage application of acellular dermal matrix and split-thickness skin graft for the coverage of full-thickness skin defects. However, they raised questions regarding what might contribute to the success of our single-stage technique. We believe that the most important factor of successful graft take is the thickness of cograft, as they mentioned. The thickness of acellular dermal matrix used in our study1 was within the range of 0.23 to 0.33 mm, and the thickness of split-thickness skin grafts in the cograft group was 0.25 mm, which means that the total thickness of cograft (acellular dermal matrix plus split-thickness skin graft) was within the threshold (0.7 mm) for successful skin grafting.2 Negative-pressure wound therapy could have promoted microcirculatory flow to the graft and wound edges; stimulated angiogenesis and basement membrane integrity; prevented complications of graft lift-off by edema, exudates, and subgraft hematoma; and reduced shear stress compared with traditional dressings.3 We used negative-pressure wound therapy to promote well-vascularized granulation tissue before skin grafting and to provide a better environment for skin graft take; thus, it is possible that negative-pressure wound therapy had a beneficial effect on successful graft take. However, negative-pressure wound therapy was used in both groups and thus could not have caused an intergroup difference. The mesh-like morphology of the acellular dermal matrix would also have promoted successful graft take by preventing fluid accumulation and hematoma formation. However, this aspect was beyond the scope of our study, and we suggest further clinical or basic study be undertaken to prove this hypothesis. Yu and Qi commented that addition of ReCell (Avita Medical, Northridge, Calif.) could improve pigmentation in the cograft group. However, we are skeptical of this notion, because split-thickness skin graft contains melanocytes and fibroblasts, and hyperpigmentation rather than hypopigmentation is more common in our patients, although we admit racial difference regarding this issue. They also suggested the insightful idea of using an acellular dermal matrix and ReCell cograft for full-thickness skin defects. We welcome this idea because such an approach could potentially treat full-thickness skin defects, with minimal donor-site morbidity. DISCLOSURE The original study was supported by a research grant from Daewoong Bio Incorporation and all of acellular dermal matrix and CURAVAC were donated by Daewoong Bio Incorporation. Otherwise, none of authors has financial interest to declare in relation to the content of this communication. Jae Kwang Kim, M.D., Ph.D.Department of Orthopedic SurgeryEwha Womans UniversitySchool of MedicineSeoul, Republic of Korea Ju Won Yi, M.D.Department of Orthopedic SurgeryArmed Forces Capital HospitalSeongnam, Republic of Korea