Biomechanics of skin grafts: effect of pattern size, spacing and orientation

Skin graft expansion is the key to the treatment of severe burn injuries requiring skin transplantation. While high expansions have been claimed by a majority of graft manufacturers, the realistic expansions reported to date with skin grafts are much lower. To clarify this discrepancy, we attempted to understand the biomechanics of skin grafts through the study of common graft pattern sizes, spacing, and orientation, and their influence on mesh expansion and induced stress. A novel skin simulant material and additive manufacturing were employed to develop the skin graft models. Tensile testing experiments were conducted to study expansion and overall stresses, and a finite element model (FEM) was used to characterize the local trends. At low strains (i.e., <1), the mesh expansion ratio was reported to be below 1, which increased up to 1.93 at a high strain of 2. The pattern size and spacing were not observed to affect the expansion much (i.e., <10%). With a change in orientation, the expansion decreased across all graft models and strains. High localized induced stresses were reported for high strains, which varied with graft orientation. The novel observations highlight the achievable expansions without overstressing, with standard slit patterning in skin grafts. These findings will not only help achieve better mesh expansion outcomes in burn surgeries but also guide the development of novel graft patterns for enhanced expansion in the future.

Management of severe burn injuries with novel treatment techniques including maggot debridement and applications of acellular fish skin grafts and autologous skin cell suspension in a dog

CASE DESCRIPTION A 3-year-old 27-kg female spayed American Bulldog with severe burn injuries caused by a gasoline can explosion was evaluated. CLINICAL FINDINGS The dog had extensive partial- and full-thickness burns with 50% of total body surface area affected. The burns involved the dorsum extending from the tail to approximately the 10th thoracic vertebra, left pelvic limb (involving 360° burns from the hip region to the tarsus), inguinal area bilaterally, right medial aspect of the thigh, and entire perineal region. Additional burns affected the margins of the pinnae and periocular regions, with severe corneal involvement bilaterally. TREATMENT AND OUTCOME The dog was hospitalized in the hospital’s intensive care unit for 78 days. Case management involved provision of aggressive multimodal analgesia, systemic support, and a combination of novel debridement and reconstructive techniques. Debridement was facilitated by traditional surgical techniques in combination with maggot treatment. Reconstructive surgeries involved 6 staged procedures along with the use of novel treatments including applications of widespread acellular fish (cod) skin graft and autologous skin cell suspension. CLINICAL RELEVANCE The outcome for the dog of the present report highlighted the successful use of maggot treatment and applications of acellular cod skin and autologous skin cell suspension along with aggressive systemic management and long-term multimodal analgesia with debridement and wound reconstruction for management of severe burn injuries encompassing 50% of an animal’s total body surface area.

The rise of factor X level in blood plasma of patients at severe burn injuries

This work is dedicated to the detection of imbalance between the pro- and anti-coagulant branches of hemostasis at severe burn injuries by evaluating the content or activity of individual clotting factors. To select the targets for accurate diagnostics we measured the concentrations of soluble fibrin monomeric complexes and fibrinogen, levels of total prothrombin, factor X, protein C and antithrombin III, and recorded the time of clotting in activated partial thromboplastin time and prothrombin time tests. Factor X level was increased in 26 % of patients on the first day after the burn and it rose further in 62 % patients on the 14 th day of recovery. Increasing factor X level is assumed to be a risk factor of thrombotic complications. We propose to use it as a marker of predisposition to thrombosis at severe burn injury.

Expansion potential of skin grafts with novel I-shaped auxetic incisions

Severe burn injures lead to millions of fatalities every year due to lack of skin replacements. While skin is a very limited and expensive entity, split thickness skin grafting, which involves the projection of a parallel incision pattern on a small section of healthy excised skin, is typically employed to increase the expansion and cover a larger burn site. To date, the real expansion capacity of such grafts are low (<3 times) and insufficient for treatment of severe burn injuries. In this study, novel I-shaped auxetic incision patterns, which are known to exhibit high negative Poisson’s ratios, have been tested on the skin to investigate their expansion potential. Fourteen two-layer skin graft models with varying incision pattern parameters (i.e., length, spacing, and orientation) were developed using finite element modelling and tested under uniaxial and biaxial tensile loads. The Poisson’s ratio, meshing ratios, and induced stresses were quantified across all models. Graft models tested uniaxially along the orthogonal directions indicated opposite trends in generated Poisson’s ratios, as the length of the I-shape incisions were increased. Biaxially, with a symmetric and closely spaced I-shape pattern, graft meshing ratios up to 15.65 were achieved without overstressing the skin. Overall, the findings from the study indicated that expansion potentials much higher than that of traditional skin grafts can be achieved with novel I-shaped auxetic skin grafts, which would be indispensable for covering large wounds in severe burn injuries.

The dignity of burn patients: a qualitative descriptive study of nurses, family caregivers, and patients

Background As an ethical principle, showing respect for human dignity is a professional duty of all nurses. The aggressive nature of severe burn injuries makes it hard to respect the existential values and dignity of burn patients. However, only a few studies have been conducted on the preservation of the dignity of burn patients. The purpose of this study is to identify and describe burn patients’ dignity as perceived by nurses, family caregivers, and burn patients. Methods The present study has a descriptive, qualitative research design. Nurses, family caregivers and patients in the biggest burns hospital in the south of Iran were selected via purposeful sampling from October 2017 to August 2018 (n = 25). Data were collected using semi-structured, in-depth, individual interviews. Thereafter, data analysis was performed through conventional content analysis. Results Three main themes were extracted from the information obtained in the interviews: empathic communication, showing respect, and providing comprehensive support. Conclusion The care provided to burn patients should be combined with effective communication, spending time with them, and attending to their repetitive requests, so that they can freely express their feelings and concerns. In addition, the patients’ human values and beliefs should be respected and all aspects of their existence should be taken into account to preserve their dignity. Workshops designed based on the findings of the present study can help with improving the quality of burn nursing care.

State of the Art: An Update on Adult Burn Resuscitation

Treatment of patients with severe burn injuries is complex, relying on attentive fluid resuscitation, successful management of concomitant injuries, prompt wound assessment and closure, early rehabilitation, and compassionate psychosocial care. The goal of fluid resuscitation is to maintain organ perfusion at the lowest possible physiologic cost. This requires careful, hourly titration of the infusion rate to meet individual patient needs, and no more; the risks of over-resuscitation, such as compartment syndromes, are numerous and life-threatening. Recognizing runaway resuscitations and understanding how to employ adjuncts to crystalloid resuscitation are paramount to preventing morbidity and mortality. This article provides an update on fluid resuscitation techniques in burn patients, to include choosing the initial fluid infusion rate, using alternate endpoints of resuscitation, and responding to the difficult resuscitation.

Long-term Outcomes after Toe-To-Thumb Transfers for Burn Reconstruction in Children

Children are one of the most vulnerable populations to burns, and hands are frequently burned anatomical structures. Restoring function in a severely burned pediatric hand is challenging. We present our experience with pediatric toe-to-thumb transfers for burn reconstruction. A retrospective review was conducted of all pediatric toe-to-thumb transfer patients between 2009 and 2014. Children under the age of 18 who underwent secondary reconstruction after electrical or thermal burn injuries with at least 5-year follow-up were included. Functional outcomes were measured with the modified Kapandji score. Complications of the reconstructed hand as well as donor foot were recorded. Four children with 10 toe-to-hand transfers (4 great toes, 2 second toes, and 2 combined second-third toes) met the inclusion criteria. Average follow-up length was 104 months (range 60-144 months) Two children sustained thermal burn injuries and two sustained electrical burn injuries. Three children achieved opposition of the reconstructed toe-to-thumb transfer to the small finger (Kapandji score 5), and one child achieved opposition of the reconstructed toe-to-thumb transfer to the proximal phalanx of the middle finger, the only remaining finger (Kapandji score 3). No donor foot morbidities were noted postoperatively. Toe-to-thumb transfers should be considered the gold standard for thumb reconstruction in children with severe burn injuries of their hands and provide restoration of sensation, pinch, grasp and opposition with minimal morbidity of the donor foot.

Burn infections characteristics: A review

Burn injuries are unique in comparison to other types of trauma because of their severity and major systemic impact produced by extensive lesions with disfunctions that can persist even several years after the injury. Multiple complications can occur during burn injury evolution, from which infections are the most severe and the most frequently encountered, requiring adequate diagnosis and treatment. In most burn centers, increased mortality rates associate with severe burn injuries aggravated by the development of sepsis. There are multiple sources of infections in burned patients: lungs, wounds, catheters, gastrointestinal and urinary tract. Pathogens are often multi-resistant bacteria but also fungi and viruses appear as opportunistic infections. The main goal is represented by prevention of organ dysfunction development through specific supportive measures that avoid its onset. Early excision of the burn eschar and wound grafting is essential for patient outcome, decreasing duration of hospitalization, infectious risk and mortality. As a principle, antibiotic treatment in burn infectious complications is started empirically, with broad spectrum agents if the results of microbiological cultures are not available and immediately after the antibiogram is available, targeted antibiotic is introduced. De-escalation strategy is promoted in order to prevent antimicrobial resistance: narrow spectrum drugs with proven efficacy on determined germs are administered, avoiding if possible, reserve antibiotics.

Serum Albumin Concentration on Admission as a Predictor of Morbidity and Mortality in Patients With Burn Injuries

Efforts have been made to determine new predictors of morbidity and mortality in patients with severe burn injuries. This prospective cohort study aimed to determine the association of serum albumin concentration on admission and renal failure, pulmonary infection, sepsis, and death in patients with burn injuries. We included 141 patients, aged &gt;18 years, who were admitted to our institution between April and August 2018. Among them, 59.1% were male and 83.8% had burns covering &lt;20% of the body surface area. Scalds were the most common cause of burns (34.8%). Twelve patients died, of whom eight (66.6%) had an Abbreviated Burn Severity Index (ABSI) ≥8. Patients with serum albumin ≤2.2 g/dL had a higher mortality rate than those with &gt;2.2 g/dL (odds ratios [OR]: 18.7; 95% confidence interval [CI]: 4.9 to 70.8). Serum albumin ≤2.2 g/dL was also significantly associated with pulmonary infection (OR: 13.1, 95% CI: 3.8 to 45.7), renal failure (OR: 30.2, 95% CI: 7.4 to 122.3), and sepsis (OR: 16.9, 95% CI: 4.9 to 58.3). Serum albumin concentration cut-points and ABSIs were determined to be death predictors using areas under the receiver operating characteristic curves (AUCs). The AUCs with albumin or ABSI alone were 0.89 (95% CI: 0.79 to 0.98) and 0.92 (95% CI: 0.87 to 0.96), respectively. The AUC including both albumin and ABSI was 0.96 (95% CI: 0.90 to 0.98), indicating that the combination is a better death predictor than either measure alone. We confirmed that burn patients with a serum albumin concentration ≤2.2 g/dL on admission have substantially increased morbidity and mortality.