Jozef Verbelen

Assessment of burn depth and burn wound healing potential

The depth of a burn wound and/or its healing potential are the most important determinants of the therapeutic management and of the residual morbidity or scarring. Traditionally, burn surgeons divide burns into superficial which heal by rapid re-epithelialization with minimal scarring and deep burns requiring surgical therapy. Clinical assessment remains the most frequent technique to measure the depth of a burn wound although this has been shown to be accurate in only 60-75% of the cases, even when carried out by an experienced burn surgeon. In this article we review all current modalities useful to provide an objective assessment of the burn wound depth, from simple clinical evaluation to biopsy and histology and to various perfusion measurement techniques such as thermography, vital dyes, video angiography, video microscopy, and laser Doppler techniques. The different needs according to the different diagnostic situations are considered. It is concluded that for the initial emergency assessment, the use of telemetry and simple burn photographs are the best option, that for research purposes a wide range of different techniques can be used but that, most importantly, for the actual treatment decisions, laser Doppler imaging is the only technique that has been shown to accurately predict wound outcome with a large weight of evidence. Moreover this technique has been approved for burn depth assessment by regulatory bodies including the FDA.

Honey in modern wound care: A systematic review

Honey, known for centuries as a topical treatment for a wide range of wounds, has recently known a revival in modern wound care. The objective of this systematic review is to evaluate the available evidence and the role of honey in contemporary wound care. The search strategy was developed in the databases PubMed and ISI Web of Science. Fifty-five studies of any design, evaluating the use of honey in human burns, ulcers and other wounds, written in English, French, German or Dutch were eligible for inclusion. In all three wound categories honey seems to be a dressing with wound healing stimulating properties. In burns there is also evidence for its antibacterial capacity. In general, honey is also been mentioned to have deodorizing, debridement, anti-inflammatory and wound pain reducing properties, although the evidence for these properties is rather limited. Many of the included studies have methodological problems, and the quality of certain studies is low, making it difficult to formulate conclusive guidelines. This review reveals several gaps in the research of honey in modern wound care, and recommendations are suggested for future research.

Burn scar assessment: A systematic review of objective scar assessment tools

PURPOSE All deep second and third degree burns are at risk to develop hypertrophic scars which can severely undermine the quality of survival. To assess the severity of scarring, several technical devices or tools have been introduced to evaluate one or more aspects of the scar, enabling comparison of different treatment protocols and allowing an objective follow-up. The objective of this study was to review which tools can be used in objective burn scar assessment. BASIC PROCEDURES The Systematic literature search involving PubMed, the Web of Science (incl. Science Citation Index). MAIN FINDINGS 51 articles with burn scar assessment as main topic were found. Several characteristics of the scar can be assessed, such as color, metric features and elasticity, but none of the available tools covers the whole aspect of the scar. Especially subjective factors such as pain and itching cannot be assessed with those tools, in spite of their great impact on the patients quality of life. CONCLUSIONS Scar tools enable objective and reproducible evaluation of scars, which is essential for scientific studies and medico-legal purposes, and in selected cases for the clinical follow-up of an individual patient. Further studies to evaluate these tools on scars are nevertheless required.

Skin replacement in burn wounds.

Historically, the main goal in burn management was increasing the survival of severely burned patients by rapid debridement and early closure of burn wounds, consequently reducing the infection risk.1–4 However, in the last decennia, surgical emphasis has shifted from survival to “quality of survival,” especially by improving the residual scars and preventing contractures. Traditionally, surgeons divide burns into deep burns requiring surgical therapy, and superficial burns which heal spontaneous by re-epithelialization with minimal scarring. Nevertheless, there is a gray zone between those two groups in which therapeutic decision making is difficult. The final decision for surgery generally remains case and surgeon dependent, and will mainly depend on the total burned surface area.5 Wound closure can be obtained by diverse therapeutic modalities depending on the depth and healing potential of the burn wound.5 In this article, the main focus is on the surgical treatment of deep dermal and full thickness burns. We endeavor to give a comprehensive overview of the developments in skin substitutes, which is impossible without mentioning some alternative treatments. The current golden standard for deep burns is surgical debridement and closure with autologous split thickness skin grafts or “STG” (epidermis plus a thin layer of dermis). Nevertheless, donor areas are limited in extended burns, and the residual scars remain unsatisfactory due to the lack of dermis. A more aesthetical reconstruction can be obtained with full thickness skin grafts (epidermis and whole dermis), which are limited in dimension and can only be harvested in a few areas (groin, lower abdomen, etc.). Deep defects with exposed bone or neurovascular structures are currently treated with flap surgery, which gives an optimal aesthetical and functional result. Nevertheless, the severe donor-site morbidity, the technical difficulty, and sometimes severe complications limit its use mostly to secondary reconstructions. Consequently, alternative conservative and surgical treatments were developed to improve the healing and the quality of the residual scars.6 Several mechanisms are supposed to enhance healing: (i) providing the ideal wound environment (wound dressings, etc.), (ii) by assisting the intrinsic healing capacities (growth factors, cytokines, etc.), or (iii) by surgically replacing the damaged skin (“skin substitutes”), which also should reduce scarring in full thickness defects. A permanent skin substitute is a surgically fixated “long lasting” skin replacement, consisting of naturally occurring skin elements which become incorporated in the normal skin. The main issue of this definition is the longevity of a skin substitute, which seems to be mostly of commercial importance, where terms such as biological dressings, and permanent and temporary skin substitutes are used without a clear distinction. This literature review showed that technically similar products are commercialized as “permanent” by one company and as biological dressing by another. Therefore, we chose to divide all these products in the following categories, depending on the skin layer which is (temporary) replaced: epidermal, dermal and combined skin substitutes (or composite grafts; Fig. 1). In the future, a fourth group might need to be added: the combined skin substitute with a subcutaneous adipose layer.7 However, the difference between skin replacements and some wound dressings can be small. Wound dressings are intended for coverage instead of replacement, to optimize wound healing. Wound dressings can roughly be divided in dressings containing natural elements (such as honey ointments), synthetic dressings (such as silver-impregnated dressings), and biological dressings containing mammalian cells or cell-derived substances like collagens and growth factors (human donor skin). Synthetically manufactured, naturally occurring elements, such as cellulose membranes, are also synthetic dressings. Wound dressings are not considered as (permanent) skin substitutes because they are not incorporated in the healing wound. Some authors previously named some of these products “skin substitutes” (without mentioning “permanent”) but this only lead to confusing terminology. The most important biological dressing, used since the 1940s, is human donor skin or “cadaver skin.”8 It contains several beneficial factors (growth factors, cytokines, etc.), and it provides the ideal environment for healing. Because of better preservation techniques (glycerol or cryopreserved), the risk of infection transmission is minimized, and its rejection will be delayed up to 3 weeks to 5 weeks.8,9 One of the Submitted for publication May 18, 2009. Accepted for publication November 6, 2009. Copyright

Burn Scar Assessment: A Systematic Review of Different Scar Scales

BACKGROUND Scars can be devastating and disfiguring, because they are clearly visible, stigmatizing, and permanent reminders of the initial accident or surgical event. Yet, there is still no consensus about the optimal scale or tool to assess the characteristics and evolution. Our aim was to evaluate the clinical importance of scar scales specifically developed for burn scars. MATERIALS AND METHODS The systematic literature search involved PubMed and the Web of Science (including Science Citation Index). RESULTS The search resulted in 29 articles (including seven reviews) dealing with a new, modified, or validated scale. Scar scales assess several characteristics, of which color, pliability, and thickness were considered the most important. Physical limitation, pain, and pruritus are often more disturbing than the appearance of the scar, and are therefore also introduced in scar evaluation, as well as the interference with daily life activities (e.g., psychologic impact). CONCLUSION In contrast to the more objective scar assessment tools, scar scales usually cover more aspects of the scars and are less time-consuming in clinical practice. However, no strong conclusions can be made about their efficacy and validity. In addition to digital photography, scar scales are a valuable instrument in the clinical evaluation and follow-up of scars.

Aquacel(®) Ag dressing versus Acticoat™ dressing in partial thickness burns: a prospective, randomized, controlled study in 100 patients. Part 1: burn wound healing.

INTRODUCTION Studies comparing contemporary silver dressings in burns are scarce. METHODS In a prospective, randomized, controlled study, counting 50 patients/research group, we compared two frequently used silver dressings, Acticoat™ and Aquacel(®) Ag, in the management of partial thickness burns with a predicted healing time between 7 and 21 days as assessed by laser Doppler imaging between 48 and 72h after burn. Variables investigated were related to baseline research group characteristics, wound healing, bacteriology, economics, nurse, and patient experience. RESULTS Both research groups were comparably composed taking into account gender, age and burn characteristics. Similar results were obtained as to healing time and bacterial control with both silver dressings. A statistically significant difference in favor of the Aquacel(®) Ag dressing was found for average ease of use (p<0.001), average ease of application (p=0.001), patient pain (p<0.001), patient comfort with the dressing (p=0.017), silver staining (p<0.001), and cost effectiveness (p<0.001). CONCLUSION Both silver dressings resulted in comparable healing times and bacterial control but the Aquacel(®) Ag dressing significantly increased comfort for patients as well as nurses and was significantly more cost-effective than the Acticoat™ dressing for the given indication.

Scar management by means of occlusion and hydration: A comparative study of silicones versus a hydrating gel-cream

Despite the worldwide use of silicones in scar management, its exact working mechanism based on a balanced occlusion and hydration, is still not completely elucidated. Moreover, it seems peculiar that silicones with completely different occlusive and hydrating properties still could provide a similar therapeutic effect. The objective of the first part of this study was to compare the occlusive and hydrating properties of three fluid silicone gels and a hydrating gel-cream. In a second part of the study these results were compared with those of silicone gel sheets. Tape stripped skin was used as a standardized scar like model on both forearms of 40 healthy volunteers. At specific times, trans epidermal water loss (TEWL) and the hydration state of the stratum corneum were measured and compared with intact skin and a scar-like control over a 3-4h period. Our study clearly demonstrated that fluid silicone gels and a hydrating gel-cream have comparable occlusive and hydrating properties while silicone gel sheets are much more occlusive, reducing TEWL values far below those of normal skin. A well-balanced, hydrating gel-cream can provide the same occlusive and hydrating properties as fluid silicone gels, suggesting that it could eventually replace silicones in scar treatment.

Glyaderm® dermal substitute: Clinical application and long-term results in 55 patients

INTRODUCTION Glycerol preserved acellular dermis (Glyaderm(®)) consists of collagen and elastin fibers and is the first non-profit dermal substitute derived from glycerol-preserved, human allogeneic skin. It is indicated for bi-layered skin reconstruction of full thickness wounds. METHODS A protocol for clinical application and optimal interval before autografting with split thickness skin graft (STSG) was developed in a pilot study. A phase III randomized, controlled, paired, intra-individual study compared full thickness defects engrafted with Glyaderm(®) and STSG versus STSG alone. Outcome measures included percentage of Glyaderm(®) take, STSG take, and scar quality assessment. RESULTS Pilot study (27 patients): Mean take rates equaled 91.55% for Glyaderm(®) and 96.67% for STSG. The optimal autografting interval was 6 days (±1 day). Randomized trial (28 patients): Mean Glyaderm(®) take rate was 88.17%. STSG take rates were comparable for both research groups (p=0.588). One year after wound closure, Glyaderm(®)+STSG was significantly more elastic (p=0.003) than STSG alone. Blinded observers scored Glyaderm(®) treated wounds better in terms of scar quality. DISCUSSION The efficacy of Glyaderm(®) as a suitable dermal substitute for full thickness wounds is attested. Currently a procedure for simultaneous application of Glyaderm(®) and STSG is adopted, allowing for further widespread use of Glyaderm(®).

A new, fast LDI for assessment of burns: A multi-centre clinical evaluation

INTRODUCTION Laser Doppler imaging (LDI) provides early accurate determination of wound healing potential. LDI can scan large areas of up to 2500 cm2 within 2 min. This duration may require additional sedation in a mobile, uncooperative child. In five burn centres a faster Laser Doppler Line Scanner (LDLS) was assessed. This new imager scans 300 cm2 in 4s with potential benefit for patients and operators. The aim of this study was to assess the accuracy and convenience of the LDLS and to compare this with an established LDI imager. METHODS Outpatients and admitted patients were included. LDI and LDLS images were obtained between 2 and 5 days post burn (PB). Photographs and records of wound and healing were obtained on day of scan and at 14 and 21 days PB. This provided data on three categories of burn wounds: healing within 14 days, 14-21 days and not healed within 21 days. RESULTS The analysis included 596 burn areas from 204 burns patients. An accuracy of 94.2% was found with use of the LDLS compared with 94.4% for the original LDI imager. CONCLUSIONS The high accuracy of the new line-scan imager was comparable to that of the traditional LDI. Its size and mobility enabled easier ward and outpatient use. The higher scan speed was particularly beneficial for scans in paediatric patients.

Exposed tibial bone after burns: Flap reconstruction versus dermal substitute

A 44 years old male patient had suffered extensive 3rd degree burns on both legs, undergoing thorough surgical debridement, resulting in both tibias being exposed. Approximately 5 months after the incident he was referred to the Department of Plastic and Reconstructive Surgery of the University Hospital Gent, Belgium, to undergo flap reconstruction. Free flap surgery was performed twice on both lower legs but failed on all four occasions. In between flap surgery, a dermal substitute (Integra(®)) was applied, attempting to cover the exposed tibias with a layer of soft tissue, but also without success. In order to promote the development of granulation tissue over the exposed bone, small holes were drilled in both tibias with removal of the outer layer of the anterior cortex causing the bone to bleed and subsequently negative pressure wound therapy (NPWT) was applied. The limited granulation tissue resulting from this procedure was then covered with a dermal substitute (Glyaderm(®)), consisting of acellular human dermis with an average thickness of 0.25mm. This dermal substitute was combined with a NPWT-dressing, and then served as an extracellular matrix (ECM), guiding the distribution of granulation tissue over the remaining areas of exposed tibial bone. Four days after initial application of Glyaderm(®) combined with NPWT both tibias were almost completely covered with a thin coating of soft tissue. In order to increase the thickness of this soft tissue cover two additional layers of Glyaderm(®) were applied at intervals of approximately 1 week. One week after the last Glyaderm(®) application both wounds were autografted. The combination of an acellular dermal substitute (Glyaderm(®)) with negative pressure wound therapy and skin grafting proved to be an efficient technique to cover a wider area of exposed tibial bone in a patient who was not a candidate for free flap surgery. An overview is also provided of newer and simpler techniques for coverage of exposed bone that could question the universal plastic surgery paradigm that flap surgery is the only way to cover these defects.