Superiority of a Silk Surgical Site Wound Closure Device Over Synthetic Dressings.

BACKGROUND: Silk fibroin is an emerging biomaterial with enhanced properties of cellular regeneration, growth and proliferation. The use of a silk fibroin wound dressing has the potential to decrease the incidence of wound healing complications and to improve patient outcomes compared to synthetic dressing alternatives. METHODS: A prospective, randomized, single-blinded clinical trial was conducted on 50 patients who were dressed with a silk fibroin dressing on one side of their body and on the contralateral side with 3M Steri-Strips® after undergoing abdominoplasty, reduction mammaplasty, or brachioplasty procedures. Data was collected over 5 postoperative visits using photographs and an investigator administered questionnaire to monitor erythema, skin irritation, skin discomfort, the need for pharmaceutical intervention, wound dehiscence and mechanical skin injury. A comprehensive 75 patient statistical analysis was conducted combining the results with a previously published study comparing Dermabond® Prineo® to the silk dressing. RESULTS: 20.8% (10/48) of patients were assessed by surgeons as having skin erythema (7-10) on the Steri-Strip® control side and 0% (0/48) on the silk dressing side (p=0.002). The frequency of breast triple point separation in 43 cases was 30.2% (13/43) on the Steri-Strip® side and 9.3% (4/43) on the silk side (p=0.012). 75% (36/48) of patients had partial or total detachment of Steri-Strips® while 0% (0/48) had total detachment of the silk dressing and 18.8% (9/48) had partial detachment of the silk dressing within the first two weeks (p<0.001). CONCLUSION: A silk fibroin wound dressing significantly reduces the incidence of wound healing complications throughout the postoperative period.Clinical Relevance Statement: The adoption of a silk fibroin wound dressing into clinical practice has the potential to improve patient outcomes, decrease medical adhesive related skin injuries and reduce the rate of wound healing complications.

Current concepts related to hypertrophic scarring in burn injuries.

Scarring following burn injury and its accompanying aesthetic and functional sequelae still pose major challenges. Hypertrophic scarring (HTS) can greatly impact patients' quality of life related to appearance, pain, pruritus and even loss of function of the injured body region. The identification of molecular events occurring in the evolution of the burn scar has increased our knowledge; however, this information has not yet translated into effective treatment modalities. Although many of the pathophysiologic pathways that bring about exaggerated scarring have been identified, certain nuances in burn scar formation are starting to be recognized. These include the effects of neurogenic inflammation, mechanotransduction, and the unique interactions of burn wound fluid with fat tissue in the deeper dermal layers, all of which may influence scarring outcome. Tension on the healing scar, pruritus, and pain all induce signaling pathways that ultimately result in increased collagen formation and myofibroblast phenotypic changes. Exposure of the fat domes in the deep dermis is associated with increased HTS, possibly on the basis of altered interaction of adipose-derived stem cells and the deep burn exudate. These pathophysiologic patterns related to stem cell-cytokine interactions, mechanotransduction, and neurogenic inflammation can provide new avenues of exploration for possible therapeutic interventions.

Current concepts on burn wound conversion-A review of recent advances in understanding the secondary progressions of burns.

Burn wound conversion describes the process by which superficial partial thickness burns convert into deeper burns necessitating surgical intervention. Fully understanding and thus controlling this phenomenon continues to defy burn surgeons. However, potentially guiding burn wound progression so as to obviate the need for surgery while still bringing about healing with limited scarring is the major unmet challenge. Comprehending the pathophysiologic background contributing to deeper progression of these burns is an essential prerequisite to planning any intervention. In this study, a review of articles examining burn wound progression over the last five years was conducted to analyze trends in recent burn progression research, determine changes in understanding of the pathogenesis of burn conversion, and subsequently examine the direction for future research in developing therapies. The majority of recent research focuses on applying therapies from other disease processes to common underlying pathogenic mechanisms in burn conversion. While ischemia, inflammation, and free oxygen radicals continue to demonstrate a critical role in secondary necrosis, novel mechanisms such as autophagy have also been shown to contribute affect significantly burn progression significantly. Further research will have to determine whether multiple mechanisms should be targeted when developing clinical therapies.

Stromal vascular fraction: A regenerative reality? Part 2: Mechanisms of regenerative action.

Adipose tissue is a rich source of cells with emerging promise for tissue engineering and regenerative medicine. The stromal vascular fraction (SVF), in particular, is an eclectic composite of cells with progenitor activity that includes preadipocytes, mesenchymal stem cells, pericytes, endothelial cells, and macrophages. SVF has enormous potential for therapeutic application and is being investigated for multiple clinical indications including lipotransfer, diabetes-related complications, nerve regeneration, burn wounds and numerous others. In Part 2 of our review, we explore the basic science behind the regenerative success of the SVF and discuss significant mechanisms that are at play. The existing literature suggests that angiogenesis, immunomodulation, differentiation, and extracellular matrix secretion are the main avenues through which regeneration and healing is achieved by the stromal vascular fraction.

Stromal vascular fraction: A regenerative reality? Part 1: Current concepts and review of the literature.

Stromal Vascular Fraction (SVF) is a heterogeneous collection of cells contained within adipose tissue that is traditionally isolated using enzymes such as collagenase. With the removal of adipose cells, connective tissue and blood from lipoaspirate, comes the SVF, a mix including mesenchymal stem cells, endothelial precursor cells, T regulatory cells, macrophages, smooth muscle cells, pericytes and preadipocytes. In part 1 of our 2-part series, we review the literature with regards to the intensifying interest that has shifted toward this mixture of cells, particularly due to its component synergy and translational potential. Trials assessing the regenerative potential of cultured Adipose Derived Stem Cells (ADSCs) and SVF demonstrate that SVF is comparably effective in treating conditions ranging from radiation injuries, burn wounds and diabetes, amongst others. Aside from their use in chronic conditions, SVF enrichment of fat grafts has proven a major advance in maintaining fat graft volume and viability. Many SVF studies are currently in preclinical phases or are moving to human trials. Overall, regenerative cell therapy based on SVF is at an early investigative stage but its potential for clinical application is enormous.

Freeman-Sheldon syndrome and respiratory obstruction: a novel use of distraction osteogenesis.

Freeman-Sheldon syndrome, or distal arthrogryposis type IIA (DA 2A), is a rare and severe multiple congenital contracture syndrome that is associated with upper airway obstruction. This obstruction has been clinically significant enough to warrant tracheostomy and has been associated with mortality. We describe a patient who presented to us as a neonate and the novel management of her respiratory obstruction in the setting of DA 2A. Bilateral mandibular osteotomies were performed and bilateral internal mandibular distracters were placed. She was distracted a total of 3 cm over 15 days without event and successfully extubated on the postoperative day 16. Preoperative polysomnogram demonstrated an obstructive apnea hypopnea index of 43.7, but a repeat polysomnogram demonstrated an apnea hypopnea index of 8.1. In this study, we report the first use of distraction osteogenesis in the setting of severe obstructive sleep apnea syndrome secondary to DA 2A.

Perineal and lower extremity reconstruction.

LEARNING OBJECTIVES: After reading this article, the participant should be able to: 1. Perform a preoperative assessment of patients undergoing perineal and lower extremity reconstruction. 2. Describe the various tissue flaps used to perform these reconstructions and the advantages and disadvantages of each. 3. Provide appropriate postoperative care and interventions to maximize outcomes. BACKGROUND: The lower extremity and perineum provide the foundation for upright posture and ambulation. These areas are made up of intricate contours with variable skin types and must withstand the functional demands of organ orifice support and weight-bearing forces. Successful reconstruction calls for careful preoperative planning and consideration of the site-specific demands. METHODS: The authors reviewed literature regarding the most current treatment strategies for lower extremity and perineal reconstruction. RESULTS: Perineal reconstruction is typically related to genitourinary or digestive tract abnormalities, mainly malignancies. Local and regional flaps are the mainstay of therapy, depending on their availability and the need for adjuvant therapy. Postoperatively, pressure reduction and closed-suction drainage are of major consideration. The lower extremities are prone to trauma, and these wounds often involve underlying and exposed bony abnormalities, and this must be considered in operative planning. Significant defects may be reconstructed with local or regional flaps and free-tissue transfer. The location of the wound and extent of surrounding tissue compromise are of major concern when determining flap coverage. Postoperatively, transition to ambulation and weight-bearing status is paramount. CONCLUSIONS: Reconstruction of the lower extremity and perineum requires recognition of the high functional demands of these areas. Local and regional flaps and free tissue transfer allow reconstruction of complex wounds in these areas. Selecting the correct flap and navigating the postoperative recovery to arrive at functional restoration remain a significant challenge.

Endoscopic versus open tissue-expander placement: is less invasive better?

BACKGROUND: Skin tissue expansion provides an excellent option for reconstruction of large cutaneous defects. Unfortunately, the complication rate with tissue-expander reconstruction is very high. One potential alternative to reduce these complications and improve recovery time is to place the tissue expanders endoscopically. The authors hypothesize that endoscopic placement of tissue expanders will reduce the complication rate, operative time, and time to full expansion. METHODS: Sixty-nine patients have undergone 81 surgical procedures for placement of 202 tissue expanders over the past 8 years at the University of Michigan Health System. The charts for all patients were reviewed retrospectively and the data analyzed to evaluate outcomes following open and endoscopic tissue-expander placement. RESULTS: Fifty-one patients underwent open placement of 127 tissue expanders for reconstruction, whereas 18 patients underwent endoscopic placement of 75 expanders. The average operative time for placement of each expander was significantly reduced in the endoscopic group (34.0 minutes) compared with the open group (49.2 minutes) (p < 0.0001). The major complication rate per tissue expander was also reduced in the endoscopically placed expander group (2.7 percent) compared with the open group (22.0 percent) (p = 0.0000056). Time to full expansion and length of hospital stay were also significantly reduced in the endoscopic group (p < 0.05 and p < 0.005, respectively). CONCLUSIONS: Endoscopic tissue-expander placement significantly reduced operative time for placement of each expander, major complication rate, time to full expansion, and length of hospital stay for this reconstructive technique. The authors conclude that endoscopic placement of tissue expanders is a safe and effective method for tissue-expander reconstructions of large, difficult wounds.

Nitric oxide production by nurse shark (Ginglymostoma cirratum) and clearnose skate (Raja eglanteria) peripheral blood leucocytes.

Reactive nitrogen intermediates, such as nitric oxide (NO), are important immunomodulators in vertebrate immune systems, but have yet to be identified as mediators of host defence in any member of class Chondrichthyes, the cartilaginous fishes. In the present study, production of NO by nurse shark (Ginglymostoma cirratum) peripheral blood leucocytes (PBL) stimulated with bacterial cell wall lipopolysaccharide (LPS) was investigated. PBL were cultured for 24 to 96 h following stimulation with LPS at concentrations ranging from 0 to 25 microg ml(-1), in both serum-supplemented and serum-free culture conditions. Production of NO was measured indirectly using the Griess reaction, with maximal NO production occurring after 72 h using 10% FBS and 10 microg LPS ml(-1). Application of these culture conditions to PBL from another cartilaginous fish (clearnose skate, Raja eglanteria) resulted in a similar NO response. Addition of a specific inhibitor of inducible nitric oxide synthase (iNOS), L-N(6)-(1-iminoethyl)lysine (L-NIL), resulted in a significant decrease in the production of NO by PBL from both species.