Use of 816 consecutive burn wound biopsies to inform a histologic algorithm for burn depth categorization

Introduction Burn experts are only 77% accurate when subjectively assessing burn depth, leaving almost a quarter of patients to undergo unnecessary surgery or conversely suffer a delay in treatment. To aid clinicians in burn depth assessment (BDA), new technologies are being studied with machine learning algorithms calibrated to histologic standards. Our group has iteratively created a theoretical burn biopsy algorithm (BBA) based on histologic analysis, and subsequently informed it with the largest burn wound biopsy repository in the literature. Here, we sought to report that process. Methods The was an IRB-approved, prospective, multicenter study. A BBA was created a priori and refined in an iterative manner. Patients with burn wounds assessed by burn experts as requiring excision and autograft underwent 4mm biopsies procured every 25cm 2. Serial still photos were obtained at enrollment and at excision intraoperatively. Burn biopsies were histologically assessed for presence/absence of epidermis, papillary dermis, reticular dermis, and proportion of necrotic adnexal structures by a dermatopathologist using H&E with whole slide scanning. First degree and superficial 2 nd degree were considered to be burn wounds likely to have healed without surgery, while deep 2 nd and 3 rd degree burns were considered unlikely to heal by 21 days. Biopsy pathology results were correlated with still photos by five burn experts for consensus of final burn depth diagnosis. Results Sixty-six subjects were enrolled with 117 wounds and 816 biopsies. The BBA was used to categorize subjects’ wounds into 4 categories: 7% of burns were categorized as 1 st degree, 13% as superficial 2 nd degree, 43% as deep 2 nd degree, and 37% as 3 rd degree. Therefore 20% of burn wounds were incorrectly judged as needing excision and grafting by the clinical team as per the BBA. As H&E is unable to assess the viability of papillary and reticular dermis, with time our team came to appreciate the greater importance of adnexal structure necrosis over dermal appearance in assessing healing potential. Conclusions Our study demonstrates that a BBA with objective histologic criteria can be used to categorize BDA with clinical misclassification rates consistent with past literature. This study serves as the largest analysis of burn biopsies by modern day burn experts and the first to define histologic parameters for BDA.

First preliminary Clinical Experiences using Hyperspectral Imaging for Burn Depth Assessment of Hand Burns

The accurate assessment of burn wounds is challenging but crucial for correct diagnosis and following therapy. The most frequent technique to evaluate burn wounds remains the clinical assessment often subjective depending on the experience of the physician. Hyperspectral Imaging is intended to counteract this subjective diagnosis by an accurate and objective analysis of perfusion parameters. The purpose of this study was to analyse the ability of technical burn depth assessment and to investigate a possible link between a certain value to burn depth versus value of healthy skin references. Methods A total of 118 subjects were included in this study between July 2017 and July 2019. 74 images with dorsal hand burns and 44 images of healthy skin on the dorsal hand as control group were analysed. In Hyperspectral Imaging recordings burn wounds were analysed with special interest to wound centre, intermediate zone, and wound margin. Results Significant results were determined for the differentiation between superficial partial burns and healthy skin. Furthermore, the distinction of full thickness burns was significantly possible. Conclusion Currently, it cannot be shown that the use of Hyperspectral Imaging technology significantly assesses the actual burn depth of thermal wounds of the dorsal hand reliably. However, the results show tendencies to improved analysis for differentiations supporting physicians in early objective optimal treatment selection.

Evidence Based Burn Depth Assessment Using Laser-Based Technologies: Where Do We Stand?

Early clinical assessment of burn depth and associated healing potential (HP) remains extremely challenging, even for experienced surgeons. Inaccurate diagnosis often leads to prolonged healing times and unnecessary surgical procedures, resulting in incremental costs, and unfavorable outcomes. Laser Doppler imaging (LDI) is currently the most objective and accurate diagnostic tool to measure blood flow and its associated HP, the main predictor for a patient’s long-term functional and aesthetic outcome. A systematic review was performed on non-invasive, laser-based methods for burn depth assessment using skin microcirculation measurements to determine time to healing: Laser Doppler flowmetry (LDF), LDI and laser speckle contrast imaging (LSCI). Important drawbacks of single point LDF measurements are direct contact with numerous small points on the wound bed and the need to carry out serial measurements over several days. LDI is a fast, “non-contact,” single measurement tool allowing to scan large burned areas with a 96% accuracy. LDI reduces the number of surgeries, improves the functional and aesthetic outcome and is cost-effective. There is only limited evidence for the use of LSCI in burn depth assessment. LSCI still needs technical improvements and scientific validation, before it can be approved for reliable burn assessment. LDI has proven to be invaluable in determining the optimal treatment of a burn patient. For unclear reasons, LDI is still not routinely used in burn centers worldwide. Additional research is required to identify potential “barriers” for universal implementation of this evidence-based burn depth assessment tool.

Burn depth assessment

Burn depth assessment is key assessing healing potential and risk of scarring. It informs wound management and surgical planning. The dynamic and evolving nature of a burn wound can make this difficult. Burns which are likely to take longer than 3 weeks to heal have a significantly increased risk of hypertrophic scar formation leading to functional and aesthetic morbidity. Assessing healing potential allows the treating clinician to optimize wound care and the need for surgical intervention.