3-D Imaging Assessment of Scar Formation and Would Healing in Fat Grafted vs Non-Fat Grafted Facial Reconstruction Wound Sites

A variety of local and regional skin flaps are used for reconstruction of skin defects on the face with the intention of full wound closure, healing, and scar minimization. Scarring is an unavoidable consequence of wound healing, especially after significant facial reconstruction. Fibroblasts migrate to the injurious site where they proliferate and deposit collagen. The collagenous proteins serve to fill in the wound defect and allow epithelial cells to accumulate and repopulate the skin surface. The collagenous base is subsequently exchanged for various types of collagen and is crosslinked. Although scar formation is an important component of wound healing, patients develop scars differently based upon location and biology of the subject. Excessive scar formation may result from excessive collagen production and inadequate collagen remodeling (Gurtner).

Much effort has focused on minimizing scar formation. Such techniques have included rigorous sterilization techniques, smaller, more linear incisions, and incisions that follow normal tension lines in the skin to name only a few. However, these techniques have been mostly limited to intraoperative or pre-operative measures. And while successful in minimizing scar burden, these techniques do not address scar management post operatively.

Wound healing and scar formation follow complex biological processes dependent on inflammatory cells and growth factors. It has been shown in utero that fetal wounds are capable of scarless healing during a phase of gestation when wounds heal with a paucity of inflammatory cells (Soo, Frantz). This principle was further studied in immune deficient mice lacking both macrophages and neutrophils, which are critical to the inflammatory response. Within this experiment, both groups of mice (immunodeficient and normal mice) healed the wounds, the immunodeficient mice did so in a scarless manner (Mori, Martin). Extrapolating this information to current surgical patients, the development of an immunomodulating measure is critical to inhibiting and managing scar formation.

Adipose derived mesenchymal stem cells (ADSCs) have been studied with regard to their role in the wound healing and scar formation process and have shown great promise. In experimental studies, ADSCs have shown to promote angiogenesis, granulation and reepithelialization of the overlying wound (Ebrahimian). Whether directly or indirectly through these processes, the ADSCs also improve the appearance of resultant scars by decreasing size, contrast of scar color, and improving pliability of the scar (Blanton, Yun). However, it is not to be confused that all adipose tissue is equivalent with ADSCs. Rather, ADSCs are a particular line of cells found within adipose tissue that have the unique capability of differentiating into a variety of types of tissues, from bone to cartilage to further adipose tissue (Zuk). These cells are capable of being harvested and cultured from adipose tissue within subjects and then subsequently injected into the wound site of interest.

Fat grafting is a similar but less involved technique that harvests autologous adipose tissue but does not use cell culture techniques to isolate ADSCs from other cell lineages. Fat grafting has long been used as a technique concurrently with facial reconstruction procedures and facial rejuvenation procedures as a "filler" of sorts for facial augmentation as early as 1893 (Miller). The fat injected into the face serves as a volume expander to correct defects related to loss of muscle or bone, such as in micrognathia. Since those initial trials, the technique has been widely expanded and honed to provide the best possible contouring. In addition to the filler aspects and results of the procedure, the technique has been observed to improve skin quality in injection sites, improve pigmentation irregularities, and even improve appearance of long standing scars. However, a formal study of fat grafting's potential of improved wound healing and minimization of scar formation has never been undertaken.