[Show abstract][Hide abstract] ABSTRACT: Texture, color, and durability are important characteristics to consider for skin replacement in conspicuous and/or mobile regions of the body such as the face, neck, and hands. Although autograft thickness is a known determinant of skin quality, few studies have correlated the subjective and objective characters of skin graft healing with their associated morphologic and cellular profiles. Defining these relationships may help guide development and evaluation of future skin replacement strategies.
Six-centimeter-diameter full-thickness wounds were created on the back of female Yorkshire pigs and covered by autografts of variable thicknesses. Skin quality was assessed on day 120 using an observer scar assessment score and objective determinations for scar contraction, erythema, pigmentation, and surface irregularities. Histological, histochemical, and immunohistochemical assessments were performed.
Thick grafts demonstrated lower observer scar assessment score (better quality) and decreased erythema, pigmentation, and surface irregularities. Histologically, thin grafts resulted in scar-like collagen proliferation while thick grafts preserves the dermal architecture. Increased vascularity and prolonged and increased cellular infiltration were observed among thin grafts. In addition, thin grafts contained predominately dense collagen fibers, whereas thick grafts had loosely arranged collagen. α-Smooth muscle actin staining for myofibroblasts was observed earlier and persisted longer among thinner grafts.
Graft thickness is an important determinant of skin quality. High-quality skin replacements are associated with preserved collagen architecture, decreased neovascularization, and decreased inflammatory cellular infiltration. This model, using autologous skin as a metric of quality, may give a more informative analysis of emerging skin replacement strategies.
[Show abstract][Hide abstract] ABSTRACT: Burns are a prevalent and burdensome critical care problem. The priorities of specialized facilities focus on stabilizing the patient, preventing infection, and optimizing functional recovery. Research on burns has generated sustained interest over the past few decades, and several important advancements have resulted in more effective patient stabilization and decreased mortality, especially among young patients and those with burns of intermediate extent. However, for the intensivist, challenges often exist that complicate patient support and stabilization. Furthermore, burn wounds are complex and can present unique difficulties that require late intervention or life-long rehabilitation. In addition to improvements in patient stabilization and care, research in burn wound care has yielded advancements that will continue to improve functional recovery. This article reviews recent advancements in the care of burn patients with a focus on the pathophysiology and treatment of burn wounds.
Critical Care 06/2015; 19(1). DOI:10.1186/s13054-015-0961-2 · 4.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The increased number of chronic nonhealing wounds mirrors the epidemic of type 2 diabetes. Diabetic animal models may allow for better understanding of the pathophysiology of wound healing and may lead to the pre-clinical testing of a variety of therapeutic modalities for this patient group. The authors present an overview of the literature on excisional wound mouse models and focus on the authors' experience with the db/db mouse. Excisional wounds in wild type mice heal quickly due primarily to wound contraction, which is delayed in the db/db mouse. In this animal model it is possible to study and quantify the main mechanisms of healing and produce highly reproducible information. Differences in methodologies, infection control, as well as fine details such as the dressing option, partially explain heterogeneous results in the literature. Given the increase of the diabetic population, the db/db mouse model provides a powerful tool to study the effects of therapeutics for improving wound healing. The standardization of this animal model represents an important aspect to improve in the wound care field.
Wounds: a compendium of clinical research and practice 05/2015; 20(1):18-28. · 0.54 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective: The contemporary treatment of a full-thickness burn consists of early eschar excision followed by immediate closure of the open wound using autologous skin. However, most animal models study burn wound healing with the persistence of the burn eschar. Our goal is to characterize a murine model of burn eschar excision to study wound closure kinetics. Approach: C57BL/6 male mice were divided into three groups: contact burn, scald burn, or unburned control. Mice were burned at 80°C for 5, 10, or 20 s. After 2 days, the eschar was excised and wound closure was documented until postexcision day 13. Biopsies were examined for structural morphology and α-smooth muscle actin. In a subsequent interval-excision experiment (80°C scald for 10 s), the burn eschar was excised after 5 or 10 days postburn to determine the effect of a prolonged inflammatory focus. Results: Histology of both contact and scald burns revealed characteristics of a full-thickness injury marked by collagen coagulation and tissue necrosis. Excision at 2 days after a 20-s burn from either scald or contact showed significant delay in wound closure. Interval excision of the eschar, 5 or 10 days postburn, also showed significant delay in wound closure. Both interval-excision groups showed prolonged inflammation and increased myofibroblasts. Innovation and Conclusions: We have described the kinetics of wound closure in a murine model of a full-thickness burn excision. Both contact and scald full-thickness burn resulted in significantly delayed wound closure. In addition, prolonged interval-excision of the eschar appeared to increase and prolong inflammation.
[Show abstract][Hide abstract] ABSTRACT: Oxygen plays an important role in wound healing, as it is essential to biological functions such as cell proliferation, immune responses and collagen synthesis. Poor oxygenation is directly associated with the development of chronic ischemic wounds, which affect more than 6 million people each year in the United States alone at an estimated cost of $25 billion. Knowledge of oxygenation status is also important in the management of burns and skin grafts, as well as in a wide range of skin conditions. Despite the importance of the clinical determination of tissue oxygenation, there is a lack of rapid, user-friendly and quantitative diagnostic tools that allow for non-disruptive, continuous monitoring of oxygen content across large areas of skin and wounds to guide care and therapeutic decisions. In this work, we describe a sensitive, colorimetric, oxygen-sensing paint-on bandage for two-dimensional mapping of tissue oxygenation in skin, burns, and skin grafts. By embedding both an oxygen-sensing porphyrin-dendrimer phosphor and a reference dye in a liquid bandage matrix, we have created a liquid bandage that can be painted onto the skin surface and dries into a thin film that adheres tightly to the skin or wound topology. When captured by a camera-based imaging device, the oxygen-dependent phosphorescence emission of the bandage can be used to quantify and map both the pO2 and oxygen consumption of the underlying tissue. In this proof-of-principle study, we first demonstrate our system on a rat ischemic limb model to show its capabilities in sensing tissue ischemia. It is then tested on both ex vivo and in vivo porcine burn models to monitor the progression of burn injuries. Lastly, the bandage is applied to an in vivo porcine graft model for monitoring the integration of full- and partial-thickness skin grafts.
[Show abstract][Hide abstract] ABSTRACT: The goal of burn surgical therapy is to minimize mortality and to return survivors to their preinjury state. Prompt removal of the burn eschar, early durable coverage, and late corrections of functional deformities are the basic surgical principles. The operative burden, while presumed to be substantial and significant, is neither well described nor quantified. The burn registry at the U.S. Institute of Surgical Research Burn Center was queried from March 2003 to August 2011 for all active duty burn admissions; active duty subjects were chosen to eliminate subject follow-up as a significant variable. Subject demographics including age, sex, branch of service, injury type, injury severity score, transfusion, allograft use, length of stay, mechanism of injury, and survival were tabulated as were their percentage TBSA, specific body region involvement, and nature and dates of operations performed. Univariate analysis and multiple logistic regressions were performed to determine independent factors which predict early and late operative burden. In the 8-year study period, 864 active duty patients were admitted to the burn center. Among them, 569 (66%) were operative in nature. The operations that were performed during acute hospitalization were 62%, while the remaining 38% were performed following discharge. A linear relationship exists between TBSA and the number of acute operations with an average of one acute operation required per 5% TBSA. No direct relationships however were found between TBSA and the number of reconstructive operations. Based on multiple logistic regression, battle vs nonbattle (OR, 0.559; 95% confidence interval [CI], 0.298-1.050; P = .0706), injury severity score (OR, 1.021; 95% CI, 1.003-1.039; P = .0222), intensive care unit length of stay (OR, 1.076; 95% CI, 1.053-1.099; P ≤ .0001), allograft use (OR, 2.610; 95% CI, 1.472-4.628; P = .0010), and TBSA of the trunk (OR, 0.982; 95% CI, 0.965-1.000; P = .0439) (but not overall TBSA) were associated with a high acute operative burden. Battle vs nonbattle (OR, 0.546; 95% CI, 0.360-0.829; P = .0045), and TBSA of the upper extremities (OR, 1.008; 95% CI, 1.002-1.013; P = .0042) were noted to be significant variables in predicting late reconstruction operations. The operative burden of burn, not previously well characterized, consists of operations performed during as well as after the initial hospitalization. While injury severity and truncal involvement are significant determinants of acute surgical therapy, the presence of upper extremity burns is a significant determinant of reconstruction following discharge.
Journal of burn care & research: official publication of the American Burn Association 08/2014; 36(2). DOI:10.1097/BCR.0000000000000132 · 1.43 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Bone regeneration and healing is an area of extensive research providing an ever-expanding set of not only therapeutic solutions for surgeons but also diagnostic tools. Multiple factors such as an ideal graft, the appropriate biochemical and mechanical wound environment, and viable cell populations are essential components in promoting healing. While bony tissue performs many functions, critical is mechanical strength, followed closely by structure. Many tools are available to evaluate bone quality in terms of quantity, structure, and strength; the purpose of this article is to identify the factors that can be evaluated and the advantages and disadvantages of each in assessing the quality of bone healing in both preclinical research and clinical settings.
[Show abstract][Hide abstract] ABSTRACT: Significance: While the survival rate of the severely burned patient has improved significantly, relatively little progress has been made in treatment or prevention of burn-induced long-term sequelae, such as contraction and fibrosis. Recent Advances: Our knowledge of the molecular pathways involved in burn wounds has increased dramatically, and technological advances now allow large-scale genomic studies, providing a global view of wound healing processes. Critical Issues: Translating findings from a large number of in vitro and preclinical animal studies into clinical practice represents a gap in our understanding, and the failures of a number of clinical trials suggest that targeting single pathways or cytokines may not be the best approach. Significant opportunities for improvement exist. Future Directions: Study of the underlying molecular influences of burn wound healing progression will undoubtedly continue as an active research focus. Increasing our knowledge of these processes will identify additional therapeutic targets, supporting informed clinical studies that translate into clinical relevance and practice.
[Show abstract][Hide abstract] ABSTRACT: INTRODUCTION: Non-battle injuries (NBIs) can be a source of significant resource utilization for the armed forces in a deployed setting. While the incidence and severity of craniomaxillofacial (CMF) battle injuries (BIs) have reportedly increased in the ongoing U.S. military conflicts in Iraq and Afghanistan, the prevalence and the nature of NBIs are not well described. MATERIAL AND METHODS: The Joint Theater Trauma Registry was queried from October 2001 to February 2011, covering Operations Enduring Freedom and Iraqi Freedom, for both NBIs and BIs to the CMF region. Patient demographics, injury severity score, mechanism and type of injury were included in the query. Using ICD-9 diagnosis codes, CMF injuries were classified according to type (wounds, fractures, burns, vascular injuries, and nerve injuries). Statistical analysis was performed for comparative analysis. RESULTS: NBIs constituted 24.3% of all patients with CMF injuries evacuated to a regional combat support hospital (CMF BIs 75.4%). These injuries were characterized by blunt trauma, most commonly motor vehicle collisions (37%), and falls (20%). As compared to CMF BIs, CMF NBIs resulted in less mortality (1.3% vs. 3.1%, p < 0.0001), fewer injuries per patient (1.87 vs. 2.26, p = 0.055), and a decreased severity score (ISS) (8.38 vs. 12.98, p < 0.0001). However, a significant percentage of CMF NBIs still required evacuation out of theater (27.8% of NBIs vs. 42.2% of BIs, p < 0.0001), depleting the combat strength of the deployed forces. CONCLUSIONS: CMF NBIs accounted for a substantial portion of total CMF injuries. Though characterized predominantly by blunt trauma with an overall better prognosis, its burden to the limited resources of a deployment can be significant. This descriptive study highlights the need to allocate appropriate resources for treatment of these injuries as well as strategies to reduce both its incidence and severity. LEVEL OF EVIDENCE: IV Prognostic.
Journal of cranio-maxillo-facial surgery: official publication of the European Association for Cranio-Maxillo-Facial Surgery 04/2013; 41(8). DOI:10.1016/j.jcms.2013.01.035 · 2.93 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Fractures of the mandible are among the most common facial injuries. Invasiveness of treatment should be determined by the extent of injury: degree of displacement, number of fractures, the patient's health status, and concomitant injuries. Complex, comminuted, and avulsive injuries frequently seen in combat will require coordination with multiple specialties to provide the best treatment. Stabilization treatment with arch bars or external fixators and splints is often desirable when fractures are highly comminuted or the soft tissue envelope is compromised by tissue loss or burns. In severe injuries, many times reconstruction will take several surgeries. Debridement of necrotic tissue and devascularized bone and skin grafting often are necessary before reconstruction. Microvascular or myocutaneous flaps should be considered with significant tissue loss and osteocutaneous flaps when large continuity defects are present. Most mandible fractures are repaired in a single operation. Those caused by explosives and high-velocity projectiles are more complex. Research should continue to focus on improving outcomes for these patients. Advances in tissue engineering, bone regeneration, and composite tissue allografting will have to continue if we hope to restore facial form and function for our combat wounded.
Atlas of the oral and maxillofacial surgery clinics of North America 03/2013; 21(1):61-8. DOI:10.1016/j.cxom.2012.12.003
[Show abstract][Hide abstract] ABSTRACT: PURPOSE: The mandible is the most commonly fractured bone in the craniomaxillofacial skeleton among military casualties. The purpose of this study was to characterize the nature and severity of mandibular fractures incurred by US military personnel during combat. MATERIALS AND METHODS: We queried the Joint Theater Trauma Registry from October 2001 to April 2011 using all pertinent International Classification of Diseases, Ninth Revision codes to identify fractures of the mandible. Fractures were then classified based on type and location. Chart reviews were performed on the subset of patients who were treated at San Antonio Military Medical Center to further classify the anatomic pattern and treatment of these fractures. RESULTS: We identified 391 patients with mandibular fractures, of whom 45 were transferred to San Antonio Military Medical Center. Open fractures were seen in 75% of patients. Two or more fractures of the mandible were seen in 51% of patients. Comminuted fractures were present in 84%, and 31% had segmental losses. Eighty-six percent of fractures were operative; two-thirds of patients required a single surgical procedure, whereas the remaining one-third required multiple procedures. Forty-six percent of patients had pan-facial fractures. CONCLUSIONS: Mandibular fractures as a result of combat blast injuries were characterized by a high incidence of open, comminuted, multiple fractures. Associated facial fractures were common.
Journal of oral and maxillofacial surgery: official journal of the American Association of Oral and Maxillofacial Surgeons 01/2013; 71(4). DOI:10.1016/j.joms.2012.10.030 · 1.43 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study provides objective data on the practice of allograft usage in severely burned patients. Furthermore, gaps in our knowledge are identified, and areas for further research are delineated. Using an institutional review board-approved protocol, active duty military patients injured while deployed in support of overseas contingency operations and treated at our burn center between March 2003 and December 2010 were identified. Their electronic medical records were reviewed for allograft use, TBSA burned, injury severity score, anatomic distribution of burns, operative burden, length of stay, transfusions, and outcome. Among 844 patients, 112 (13.3%) received allograft and 732 (86.7%) did not. The amount of allograft used per patient varied and was not normally distributed (median, 23.5; interquartile range, 69.5). Patients received allograft skin an average of 12.75 times during their admission. Allografted patients sustained severe burns (¼, 53.8% TBSA); most were transfused (71.2%) and grafted frequently, averaging every 7.45 days. Most commonly, allograft was placed on the extremities (66.5%) followed by the trunk (44.2%); however, the vast majority of allografted patients also had concomitant burns of the head (91.1%) and hands (87.5%). All-cause mortality among the allografted patients was 19.1%. In conclusion, allograft is commonly used in the surgical treatment of severe burns. Although there are no anatomic limitations to allograft placement, there are distinct patterns of use. Given the role of allograft in the acute management of large burns, there is need for further investigation of its effect on mortality, morbidity, and antigenicity.
Journal of burn care & research: official publication of the American Burn Association 01/2013; 34(1):168-75. DOI:10.1097/BCR.0b013e318270000f · 1.43 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Improved armor and battlefield medicine have led to better survival in the wars in Iraq and Afghanistan than any previous ones. Increased frequency and severity of craniomaxillofacial injuries have been proposed. A comprehensive characterization of the injury pattern sustained during this 10-year period to the craniomaxillofacial region is needed to improve our understanding of these unique injuries, to optimize the treatment for these patients, and to potentially direct strategic development of protective equipment in the future.
The Joint Theater Trauma Registry was queried from October 19, 2001, to March 27, 2011, covering operations Enduring Freedom and Iraqi Freedom for battle injuries to the craniomaxillofacial region, including patient demographics and mechanism of injury. Injuries were classified according to type (wounds, fractures, burns, vascular injuries, and nerve injuries) using DRG International Classification of Diseases-9th Rev. diagnosis codes.
In this 10-year period, craniomaxillofacial battle injuries to the head and neck were found in 42.2% of patients evacuated out of theater. There is a high preponderance of multiple wounds and open fractures in this region. The primary mechanism of injury involved explosive devices, followed by ballistic trauma.
Modern combat, characterized by blast injuries, results in higher than previously reported incidence of injury to the craniomaxillofacial region.
Epidemiologic study, level IV.
[Show abstract][Hide abstract] ABSTRACT: Facial injuries sustained by US military personnel during the wars in Iraq and Afghanistan have increased compared with past conflicts. Characterization of midface fractures (orbits, maxilla, zygoma, and nasal bones) sustained on the battlefield is needed to improve our understanding of these injuries, to optimize treatment, and to potentially direct strategic development of protective equipment in the future.
The military's Joint Theater Trauma Registry was queried for midface fractures from 2001 to 2011 using International Classification of Diseases, Ninth Revision diagnosis codes. Stratification was then performed, and individual treatment records from Brooke Army Medical Center were reviewed. Analysis of the fracture pattern, treatment, and complications was performed.
One thousand seven hundred sixty individuals with midface fractures were identified. Those fractures sustained in battle were characterized by a predominance of open fractures, blast etiology, and associated injuries. Detailed record reviews of the patients treated at our institution revealed 45% of all midface fractures as operative. Thirty-one percent of these were treated at levels III and IV facilities outside the continental United States before arrival at our institution. Patients with midface fractures underwent multiple operations. There was a 30% rate of complication among operative fractures characterized by malalignment, implant exposure, and infection. Midface battle injuries also had a high incidence of orbital fractures and severe globe injuries.
Midface fractures sustained in the battlefield have a high complication rate, likely as a result of the blast mechanism of injury with associated open fractures, multiple fractures, and associated injuries. These cases present unique challenges, often requiring both soft tissue and skeletal reconstruction.
The Journal of craniofacial surgery 11/2012; 23(6):1587-91. DOI:10.1097/SCS.0b013e318256514a · 0.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Large body surface area burns pose significant therapeutic challenges. Clinically, the extent and depth of burn injury may mandate the use of allograft for temporary wound coverage while autografts are serially harvested from the same donor areas. The paucity of donor sites in patients with burns involving large surface areas highlights the need for better skin substitutes that can achieve early and complete coverage and retain normal skin durability with minimal donor requirements. We have isolated autologous stem cells from the adipose layer of surgically debrided burned skin (dsASCs), using a point-of-care stem cell isolation device. These cells, in a collagen-polyethylene glycol fibrin-based bilayer hydrogel, differentiate into an epithelial layer, a vascularized dermal layer, and a hypodermal layer. All-trans-retinoic acid and fenofibrate were used to differentiate dsASCs into epithelial-like cells. Immunocytochemical analysis showed a matrix- and time-dependent change in the expression of stromal, vascular, and epithelial cell markers. These results indicate that stem cells isolated from debrided skin can be used as a single autologous cell source to develop a vascularized skin construct without culture expansion or addition of exogenous growth factors. This technique may provide an alternative approach for cutaneous coverage after extensive burn injuries.