Faculty Bibliography

BACKGROUND:The role of the wet environment in wound healing has been investigated in various studies. The current study explores the role of the wet wound environment in promoting healing of skin grafts. The authors hypothesized that the survival of skin grafts is dependent not only on the orientation of transplantation but also on the environment into which the skin is transplanted. METHODS:This study included 72 full-thickness (2.5 x 2.5-cm) wounds in six Yorkshire pigs. The wounds were grafted with autologous split-thickness skin grafts (meshed or sheet), placed either regularly (dermal side down) or inverted (dermal side up), and treated in a wet or a dry environment. Behavior of the skin grafts and healing were analyzed in histologic specimens collected on days 4, 6, 9, and 12 after wounding. Wound contraction was quantified by photoplanimetry. RESULTS:In the wet environment, not only did inverted meshed skin grafts survive, but also they proliferated to accelerate reepithelialization. In this environment, wounds transplanted with inverted and regular meshed grafts showed no significant difference in reepithelialization rate and contraction. In contrast, in the dry environment, wounds transplanted with inverted meshed grafts showed a significantly lower reepithelialization rate and a higher contraction rate than wounds transplanted with regular grafts. Inverted meshed grafts in a dry environment and inverted sheet grafts did not survive. CONCLUSION/CONCLUSIONS:The wound environment has an important role in the survival and proliferation of skin grafts, as demonstrated by survival of inverted meshed grafts in the wet environment and their contribution to accelerated reepithelialization, equal to the regularly placed grafts.

ABSTRACT Decreased inflammatory response seen in wet wound healing may be correlated with diminished scarring. This study seeks to test this hypothesis and to validate a model of scarring in the Yorkshire pig. Four Yorkshire pigs were used to create 36 dorsal wounds per pig (144 wounds total) in the following groups: full-thickness excisional, partial thickness, meshed split-thickness skin grafts, sheet split-thickness skin grafts, minced skin, and incisional wounds. Wounds were randomized into wet and dry groups. Wet wounds were enclosed in polyurethane chambers with 2 mL of normal saline. Dry wounds were covered with regular gauze. Terminal biopsies were performed at 72 hours and day 28. Histology demonstrated significantly less inflammatory infiltrate, thicker neoepidermis, more pronounced rete ridge formation, and decreased scar tissue thickness in wet wounds. The mean macroscopic scar surface area was significantly decreased in full-thickness excisional wet wounds compared with dry wounds (61.2 mm(2) vs. 150.8 mm(2), p<0.01). Hydroxyproline content was decreased in full-thickness wet compared with dry groups (44.81 vs. 62.21 mg/g, p<0.01). Tensile strength was 90% greater in full-thickness wet compared with dry groups (p<0.01). Healing in the liquid environment significantly reduced scar formation. This model will allow for future investigation of high-concentration topical scar-modulating agents in the liquid environment.

A low transverse abdominal incision, most commonly the Pfannenstiel incision, is often used in obstetric and gynecologic surgery. The Maylard low transverse abdominal incision is a rare variant in which the deep inferior epigastric vessels are ligated. This is clinically important and has significant implications for preoperative planning of reconstructive surgery based on these vessels. Four candidates for deep inferior epigastric perforator (DIEP) flap breast reconstruction were identified with a suspected Maylard incision prior to surgery. Preoperative imaging with Duplex ultrasound was important in select cases for identification of vessel patency and direction of flow. Identification of 'high-risk patients allows for appropriate patient counselling and surgical planning.

We used minced, autologous skin for neoepithelialization of surgically created subcutaneous tunnels in a large animal model. Partial-thickness skin grafts were harvested from the back region of five 50-60 kg Yorkshire pigs. The skin was minced to 0.8 x 0.8 x 0.3 mm particles. Silicone-latex tubes were covered with fibrin, rolled in minced skin, and placed in subcutaneous tunnels created in the abdominal area. For comparison, single cell suspensions of keratinocytes and fibroblasts in fibrin or fibrin only were transplanted on tubes. Tunnels were extracted after 14, 21, and 28 days for microscopic evaluation. All tubes transplanted with minced skin particles showed neoepithelialization. The epithelium was stratified and differentiated after 2 weeks in vivo, and the stratum corneum was directed toward the implanted tube. No epithelium formed from tubes transplanted with single cell suspensions, and only sparse keratinocytes could be detected by serial sectioning and immunostaining on day 14, but not later. No epithelial lining was found in tunnels with fibrin-only-coated tubes. Epithelial cysts could be found the first 2 weeks after transplantation in the minced skin group but not later. In conclusion, a minced skin technique could serve as a potential source for tissue engineering of tubular conduits for reconstructive purposes of the urethra and for cutaneous stomas for bladder catheterization, or intestinal irrigations. The method would have the advantage of being simple and expeditious and not requiring in vitro culturing.

BACKGROUND:With the investigation and potential introduction of several novel scar-reducing therapies to the market within the next several years, it is germane to review both the pathophysiology of scarring and the safety and efficacy of currently available and emerging therapeutic agents. METHODS:An extensive review of the English-language literature was conducted using the MEDLINE database. RESULTS:A comprehensive review of the pathophysiology of scarring and scar management, including both emerging and currently available therapies, was completed. Current clinical studies are limited by small sample sizes, lack of well-designed controls, and lack of standardized scar outcome measurement parameters. CONCLUSIONS:A prominent challenge in the study of scar management is the paucity of well-designed, large, randomized, controlled studies examining existing scar-reducing techniques. The greatest improvement in scar-reducing protocols likely entails a polytherapeutic strategy for management. Further investigation into the role of inflammation in scarring is paramount to the development of improved scar-reducing agents. There is a need for large controlled trials using a polytherapeutic strategy that combines existing and novel agents to provide a standardized evidence-based evaluation of efficacy.

The Wnt signaling network regulates chondrocyte differentiation, proliferation, and maturation during embryonic limb development. In this review, we summarize studies of Wnt signaling during the chondrocyte life cycle in avian and mammalian systems, both before and after birth. Recent reports that implicate abnormal Wnt signaling as a contributing factor to pathogenic joint conditions are also discussed. In addition, we show new data that suggests Wnt signaling is active in adult cartilage. Overall, it appears that the Wnt network has dual roles in cartilage, as has been described in other tissues: it is an important regulator of chondrocyte development, but deregulated signaling is detrimental to mature tissues and may lead to disease.