Differentiation of superficial-partial vs. deep-partial thickness burn injuries in vivo by confocal-laser-scanning microscopy

Effect of platelet-rich plasma in treating patients with burn wounds: A meta-analysis

A meta-analysis was conducted to investigate the effects of platelet-rich plasma (PRP) in the treatment of burn wounds and to provide a scientific basis for clinical drug therapy. We searched PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure and Wanfang databases to identify randomised controlled trials (RCTs) on PRP in treating burn wounds, with the control group being treated with conventional treatments and the intervention group being treated with PRP alone or combined with PRP on the basis of the control group. The search duration was each database's inception to September 2023. The literature was screened, data were extracted and quality was assessed by two independent researchers. Data analysis was performed using the Review Manager 5.4 software. Eighteen RCTs comprising 1463 patients were included in the analysis. The meta-analysis revealed that the application of PRP significantly improved the wound healing rate (standardised mean difference [SMD]: 1.11, 95% confidence interval [CI]: 0.54-1.67, p < 0.001), shortened wound healing time (SMD: -1.69, 95% CIs: -2.21 to -1.17, p < 0.001) and reduced the incidence of adverse events (7.03% vs. 18.93%, odds ratio [OR]: 0.32, 95% CI: 0.20-0.53, p < 0.001), and also significantly reduced patients' pain (SMD: -1.86, 95% CI: -2.47 to -1.25, p < 0.001) of burn patients when compared with the control group. This study showed that PRP is effective in repairing burn wounds, promoting wound healing, reducing the incidence of adverse events and reducing patient pain, making it worthy of clinical promotion and application.

In vivo monitoring of hemoglobin derivatives in a rat thermal injury model using spectral diffuse reflectance imaging

INTRODUCTION

To demonstrate the feasibility of our previously proposed Diffuse reflectance spectral imaging (DRSI) method for in vivo monitoring of oxygenated hemoglobin, deoxygenated hemoglobin, methemoglobin, tissue oxygen saturation, and methemoglobin saturation in a rat scald burn wound model and assess whether the method could be used for differentiating the burn depth groups in rats based on the hemoglobin parameters.

METHODOLOGY

Superficial dermal burns (SDBs), deep dermal burns (DDBs), and deep burns (DBs) were induced in rat dorsal skin using a Walker-Mason method. An approach based on multiple regression analysis for spectral diffuse reflectance images aided by Monte Carlo simulations for light transport was used to quantify the hemoglobin parameters. Canonical discriminant analysis (CDA) was performed to discriminate SDB, DDB, and DB.

RESULTS

CDA using the total hemoglobin concentration, tissue oxygen saturation, and methemoglobin saturation as the independent variables showed good performance for discriminating the SDB, DDB, and DB groups immediately after burn injury and the SDB group from the DDB and DB groups 24-72 h after burn injury.

CONCLUSIONS

The DRSI method with multiple regression analysis for quantification of oxygenated hemoglobin, deoxygenated hemoglobin, and methemoglobin proved to be reliable for monitoring these hemoglobin derivatives in the rat experimental burn injury model. The parameters of tissue oxygen saturation, methemoglobin saturation, and total hemoglobin concentration are promising for the differentiating the degree of burn injury using CDA.

Discordance between histologic and visual assessment of tissue viability in excised burn wound tissue

The regenerative capacity of burn wounds, and the need for surgical intervention, depends on wound depth. Clinical visual assessment is considered the gold standard for burn depth assessment but it remains a subjective and inaccurate method for tissue evaluation. The purpose of this study was to compare visual assessment with microscopic and molecular techniques for human burn depth determination, and illustrate differences in the evaluation of tissue for potential regenerative capacity. Using intraoperative visual assessment, patients were identified as having deep partial thickness or full thickness burn wounds. Tangential excisions of burn tissue were processed with hematoxylin and eosin to visualize tissue morphology, lactate dehydrogenase assay to ascertain cellular viability, and Keratin-15 and Ki67 to identify epidermal progenitor cells and proliferative capacity, respectively. RNA from deep partial and full thickness burn tissue as well as normal tissue controls were submitted for RNA sequencing. Lactate dehydrogenase, Keratin-15, and Ki67 were found throughout the excised burn wound tissue in both deep partial thickness burn tissues and in the second tangential excision of full thickness burn tissues. RNA sequencing demonstrated regenerative capacity in both deep partial and full thickness burn tissue, however a greater capacity for regeneration was present in deep partial thickness compared with full thickness burn tissues. In this study, we highlight the discordance that exists between the intraoperative clinical identification of burn injury depth, and microscopic and molecular determination of viability and regenerative capacity. Current methods utilizing visual assessment for depth of injury are imprecise, and can lead to removal of viable tissue. Additionally, hematoxylin and eosin microscopic analysis should not be used as the sole method in research or clinical determination of depth, as there are no differences in staining between viable and nonviable tissue.

In vivo confocal laser scanning microscopy imaging of skin inflammation: Clinical applications and research directions

In vivo confocal laser scanning microscopy (CLSM) is a novel imaging technique that provides noninvasive, morphological characterization of skin structures with a resolution that is very close to that of light microscopy. Moreover, as it allows repeated imaging of the same skin area at different time-points, it is an excellent method for monitoring disease course, response to treatment or specific stimuli and a path to study dynamic phenomena in real-time. To date, two different variants of in vivo CLSM have been authorized in dermatological field, namely the reflectance confocal microscopy predominantly for clinical diagnosis and the fluorescence confocal microscopy mainly for research purposes. This study describes the principles of in vivo CLSM technique, its role in the diagnosis and monitoring of inflammatory skin diseases, as well as some promising research directions to study the dynamics of skin inflammation using this method. In vivo CLSM evaluation of inflammatory dermatoses and of the skin inflammatory component in various diseases has an undoubted potential with broad applications ranging from clinical, morphological to experimental, functional studies involving the skin.

Hyperspectral index-based metric for burn depth assessment

Burn depth objective classification is of paramount importance for decision making and treatment. Despite the wide variety of burn depth assessment methods tested so far, none of them have gained wide clinical application. Here, we introduce a new approach for burn depth assessment based on hyperspectral imaging combined with a spectral index-based technique that exploits specific spectral bands to map skin areas with different burn degrees. The spectral index amplifies the contrast between normal skin and areas with different degrees of burn, taking advantage of the differences in spectral amplitudes that occur as a result of the morphological and physiological changes occurring in burned skin. We demonstrate that by using the new measurable spectral index, it is possible to generate accurate burn classification maps showing spatial distribution of burn types in the affected body areas, facilitating the decision-making process and prognosis evaluation. The results highlight the potential of the new hyperspectral metric in the field of burn depth classification and its applicability in hospital settings seems promising.

Thermal injury of skin and subcutaneous tissues: A review of experimental approaches and numerical models

Thermal injury to skin and subcutaneous tissue is common in both civilian and combat scenarios. Understanding the change in tissue morphologies and properties and the underlying mechanisms of thermal injury are of vital importance to clinical determination of the degree of burn and treatment approach. This review aims at summarizing the research involving experimental and numerical studies of skin and subcutaneous tissue subjected to thermal injury. The review consists of two parts. The first part deals with experimental studies including burn protocols and prevailing imaging approaches. The second part deals with existing numerical models for burns of tissue and related computational simulations. Based on this review, we conclude that though there is literature contributing to the knowledge of the pathology and pathogenesis of tissue burn, there is scant quantitative information regarding changes in tissue properties including mechanical, thermal, electrical and optical properties as a result of burns that are linked to altered tissue morphology.

Important Developments in Burn Care

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Explain the epidemiology of severe burn injury in the context of socioeconomic status, gender, age, and burn cause. 2. Describe challenges with burn depth evaluation and novel methods of adjunctive assessment. 3. Summarize the survival and functional outcomes of severe burn injury. 4. State strategies of fluid resuscitation, endpoints to guide fluid titration, and sequelae of overresuscitation. 5. Recognize preventative measures of sepsis. 6. Explain intraoperative strategies to improve patient outcomes, including hemostasis, restrictive transfusion, temperature regulation, skin substitutes, and Meek skin grafting. 7. Translate updates in the pathophysiology of hypertrophic scarring into novel methods of clinical management. 8. Discuss the potential role of free tissue transfer in primary and secondary burn reconstruction.

SUMMARY

Management of burn-injured patients is a challenging and unique field for plastic surgeons. Significant advances over the past decade have occurred in resuscitation, burn wound management, sepsis, and reconstruction that have improved outcomes and quality of life after thermal injury. However, as patients with larger burns are resuscitated, an increased risk of nosocomial infections, sepsis, compartment syndromes, and venous thromboembolic phenomena have required adjustments in care to maintain quality of life after injury. This article outlines a number of recent developments in burn care that illustrate the evolution of the field to assist plastic surgeons involved in burn care.

Hyperspectral Imaging for Burn Depth Assessment in an Animal Model

Differentiating between superficial and deep-dermal (DD) burns remains challenging. Superficial-dermal burns heal with conservative treatment; DD burns often require excision and skin grafting. Decision of surgical treatment is often delayed until burn depth is definitively identified. This study's aim is to assess the ability of hyperspectral imaging (HSI) to differentiate burn depth.

METHODS

Thermal injury of graded severity was generated on the dorsum of hairless mice with a heated brass rod. Perfusion and oxygenation parameters of injured skin were measured with HSI, a noninvasive method of diffuse reflectance spectroscopy, at 2 minutes, 1, 24, 48 and 72 hours after wounding. Burn depth was measured histologically in 12 mice from each burn group (n = 72) at 72 hours.

RESULTS

Three levels of burn depth were verified histologically: intermediate-dermal (ID), DD, and full-thickness. At 24 hours post injury, total hemoglobin (tHb) increased by 67% and 16% in ID and DD burns, respectively. In contrast, tHb decreased to 36% of its original levels in full-thickness burns. Differences in deoxygenated and tHb among all groups were significant (P < 0.001) at 24 hours post injury.

CONCLUSIONS

HSI was able to differentiate among 3 discrete levels of burn injury. This is likely because of its correlation with skin perfusion: superficial burn injury causes an inflammatory response and increased perfusion to the burn site, whereas deeper burns destroy the dermal microvasculature and a decrease in perfusion follows. This study supports further investigation of HSI in early burn depth assessment.

Utilization of laser Doppler flowmetry and tissue spectrophotometry for burn depth assessment using a miniature swine model

Currently, the diagnosis of burn depth is primarily based on a visual assessment and can be dependent on the surgeons' experience. The goal of this study was to determine the ability of laser Doppler flowmeter combined with a tissue spectrophotometer to discriminate burn depth in a miniature swine burn model. Burn injuries of varying depth, including superficial-partial, deep-partial, and full thickness, were created in seven Göttingen minipigs using an aluminium bar (100 °C), which was applied to the abdominal skin for periods of 1, 3, 6, 12, 30, and 60 seconds with gravity alone. The depth of injury was evaluated histologically using hematoxylin and eosin staining. All burns were assessed 3 hours after injury using a device that combines a laser light and a white light to determine blood flow, hemoglobin oxygenation, and relative amount of hemoglobin. The blood flow (41 vs. 124 arbitrary units [AU]) and relative amount of hemoglobin (32 vs. 52 AU) were significantly lower in full thickness compared with superficial-partial thickness burns. However, no significant differences in hemoglobin oxygenation were observed between these depths of burns (61 vs. 60%). These results show the ability of laser Doppler flowmeter and tissue spectrophotometer in combination to discriminate between various depths of injury in the minipig model, suggesting that this device may offer a valuable tool for burn depth assessment influencing burn management.

Acute effects of local cold therapy in superficial burns on pain, in vivo microcirculation, edema formation and histomorphology

BACKGROUND

Local cold therapy for burns is generally recommended to relief pain and limit tissue damage, however, there is limited data of its physiological benefit. This study aimed to evaluate pathophysiological effects of cold therapy in superficial burn on microcirculation, edema formation, and histomorphology.

METHODS

In 12 volunteers (8f, 4m; aged 30.4±14.1 years) circumscribed superficial burn was induced on both hand back and either left untreated as control (control-group) or treated by local-cold-application (cold-treatment-group). Prior to burn (t0), immediately (t1), 15 min (t2), and 30 min (t3) following cold therapy, following parameter was evaluated using intravital-microscopy; epidermal-thickness (ET), granular-cell-size (GCS), individual-blood-cell-flow (IBCF), and functional-capillary-density (FCD).

RESULTS

Both ET and GCS increased significantly more in control-group and slightly in cold-treatment-group in t1, while turns to insignificant t2 onwards. IBCF and FCD raised up in control-group compared to dramatically decrease in cold-treatment-group in t1. In t2 both parameter remains in control-group and increased in cold-treatment-group. Comparison of both groups for IBCF and FCD indicates significant difference in t1 and t2, however, insignificant in t0 and t3.

CONCLUSIONS

Microcirculation, edema formation, and histomorphology of superficial burn has been significantly influenced through immediate cold therapy, however, this alterations are transient and turns to ineffective after 30 min.

Combined reflectance confocal microscopy/optical coherence tomography imaging for skin burn assessment

A combined high-resolution reflectance confocal microscopy (RCM)/optical coherence tomography (OCT) instrument for assessing skin burn gravity has been built and tested. This instruments allows for visualizing skin intracellular details with submicron resolution in the RCM mode and morphological and birefringence modifications to depths on the order of 1.2 mm in the OCT mode. Preliminary testing of the dual modality imaging approach has been performed on the skin of volunteers with some burn scars and on normal and thermally-injured Epiderm FTTM skin constructs. The initial results show that these two optical technologies have complementary capabilities that can offer the clinician a set of clinically comprehensive parameters: OCT helps to visualize deeper burn injuries and possibly quantify collagen destruction by measuring skin birefringence, while RCM provides submicron details of the integrity of the epidermal layer and identifies the presence of the superficial blood flow in the upper dermis. Therefore, the combination of these two technologies within the same instrument may provide a more comprehensive set of parameters that may help clinicians to more objectively and nonivasively assess burn injury gravity by determining tissue structural integrity and viability.

Applicability of confocal laser scanning microscopy for evaluation and monitoring of cutaneous wound healing

There is a high demand for noninvasive imaging techniques for wound assessment. In vivo reflectance confocal laser scanning microscopy (CLSM) represents an innovative optical technique for noninvasive evaluation of normal and diseased skin in vivo at near cellular resolution. This study was designed to test the feasibility of CLSM for noninvasive analysis of cutaneous wound healing in 15 patients (7 male/8 female), including acute and chronic, superficial and deep dermal skin wounds. A commercially available CLSM system was used for the assessment of wound bed and wound margins in order to obtain descriptive cellular and morphological parameters of cutaneous wound repair noninvasively and over time. CLSM was able to visualize features of cutaneous wound repair in epidermal and superficial dermal wounds, including aspects of inflammation, neovascularisation, and tissue remodelling in vivo. Limitations include the lack of mechanic fixation of the optical system on moist surfaces restricting the analysis of chronic skin wounds to the wound margins, as well as a limited optical resolution in areas of significant slough formation. By describing CLSM features of cutaneous inflammation, vascularisation, and epithelialisation, the findings of this study support the role of CLSM in modern wound research and management.

Review of burn injury research for the year 2009

Research in burn care for the calendar year 2009 was robust and diverse with >1400 research articles published on a wide range of topics. In this review, the authors highlight some innovative and potentially impactful research related to the overall care of burn- injured patients. The authors grouped articles according to the following categories: critical care, infection, inhalation injury, epidemiology, psychology, wound characterization and treatment, nutrition and metabolism, pain and itch management, burn reconstruction, and rehabilitation. They found that the holistic nature of burn care is reflected in the diverse research performed in 2009 throughout the world and that this research has provided important evidence that has improved or will improve burn care overall.

Local burn versus local cold induced acute effects on in vivo microcirculation and histomorphology of the human skin

BACKGROUND

The impact of burns and colds on human skin microcirculation and histomorphology has not been compared as yet. Reflectance confocal microscopy (RCM) enables in vivo insight in human skin on cellular and subcellular levels. We evaluated analogies and differences of thermal injuries on microcirculation and histomorphology in vivo using RCM.

METHODS

Local superficial burn (6 female, 4 male; aged 28.4 ± 2.9 years, burn group) versus superficial cold (4 female, 6 male; aged 30.4 ± 5.2 years, cold group) was induced on the dorsum of the hand in an experimental immersion hand model. In vivo RCM was performed prior (control), immediately (t1) and 15 minutes (t2) following thermal injury to evaluate: Individual blood cell flow (IBCF), functional capillary density (FCD), epidermal thickness (ET), and granular cell size (GCS).

RESULTS

In the burn group, IBCF was increased at t1 (78.02 ± 2.60/min) and remained elevated at t2 (84.16 ± 3.04/min). In the cold group, IBCF decreased at t1 (12.62 ± 2.12 min) and increased at t2 (74.24 ± 3.14/min, P < 0.05) compared to the controls (58.23 ± 3.21/min). FCD was 6.74 ± 0.52/mm(2) in controls and increased at both t1 (7.82 ± 0.72/mm(2)) and t2 (8.02 ± 0.81/mm(2)) in the burn group. In the cold group, FCD decreased at t1 (2.60 ± 0.42/mm(2)) and increased at t2 (7.92 ± 0.44/mm(2), P < 0.05). ET increased at both t1 (43.12 ± 4.08 μm, P > 0.05) and t2 (47.26 ± 4.72 μm, P < 0.05) in the burn group. In the cold group, ET decreased at t1 (39.92 ± 3.14 μm, P > 0.05) and increased at t2 (44.72 ± 4.06 μm, P < 0.05) compared to the controls (41.26 ± 3.82 μm). Control GCS was 726.9 ± 59.4 μm(2) and increased at both t1 (739.8 ± 69.8 μm(2), P > 0.05) and t2 (762.6 ± 71.4 μm(2), P < 0.05) in the burn group. In the cold group, GCS decreased at t1 (712.4 ± 53.8 μm(2), P > 0.05) and increased at t2 (742.6 ± 64.8 μm(2), P < 0.05).

CONCLUSIONS

Superficial burn induces more cellular destruction and cold leads to huge fluctuation in tissue perfusion, however, with moderate impact on histomorphology. The effect on dermal capillaries suggests a selective neural control and cold injuries might down-regulate this system, much more than burns can activate it.

Noninvasive assessment of burn wound severity using optical technology: a review of current and future modalities

Clinical examination alone is not always sufficient to determine which burn wounds will heal spontaneously and which will require surgical intervention for optimal outcome. We present a review of optical modalities currently in clinical use and under development to assist burn surgeons in assessing burn wound severity, including conventional histology/light microscopy, laser Doppler imaging, indocyanine green videoangiography, near-infrared spectroscopy and spectral imaging, in vivo capillary microscopy, orthogonal polarization spectral imaging, reflectance-mode confocal microscopy, laser speckle imaging, spatial frequency domain imaging, photoacoustic microscopy, and polarization-sensitive optical coherence tomography.

Critical review of burn depth assessment techniques: Part I. Historical review

The assessment of burn depth, and as such, the estimation of whether a burn wound is expected to heal on its own within 21 days, is one of the most important roles of the burn surgeon. A false-positive assessment and the patient faces needless surgery, a false-negative one and the patient faces increased length of stay, risks contracture, and hypertrophic scar formation. Although many clinical signs can aid in this determination, accurate assessment of burn depth is possible only 64 to 76% of the time, even for experienced burn surgeons. Through the years, a variety of tools have become available, all attempting to improve clinical accuracy. Part 1 of this two-part article reviews the literature supporting the different adjuvants to clinical decision making is, providing a historical perspective that serves as a framework for part 2, a critical assessment of laser Doppler imaging.

Histometric and histomorphologic comparison of combustion and ambustion using in vivo reflectance-confocal microscopy

BACKGROUND

When combustion and ambustion induce a superficial injury, they are summarized as superficial burns, regardless of the underlying cause. Reflectance-confocal microscopy (RCM) allows noninvasive imaging of the human skin on morphological features. We hypothesized that combustion and ambustion have different histomorphological effects on the human skin.

METHODS

Superficial burns caused by combustion (CO-group, five females, three males; aged 26.8 +/- 14.2 years) and caused by ambustion (AM-group, four females, four males; aged 28.1 +/- 13.8 years) were evaluated 24 h after injury. The following parameters were obtained using RCM on injured and noninjured (control) site: horny layer thickness, epidermal thickness, granular cell size, basal layer thickness.

RESULTS

Compared with the controls (12.8 +/- 2.5 microm), horny layer thickness decreased significantly to 10.6 +/- 2.1 microm in the CO-group, whereas it increased significantly to 17.8 +/- 2.8 microm in the AM-group. The epidermal thickness did not differ significantly in CO-group (47.9 +/- 2.1 microm) and AM-group (49.0 +/- 3.1 microm), however, both increased significantly compared with the controls (42.7 +/- 1.6 microm). The basal layer thickness increased more in AM-group (17.0 +/- 1.2 microm) compared to CO-group (15.4 +/- 1.1 microm). Both differed significantly compared with their controls (13.9 +/- 0.9 microm). The granular cell size increased significantly in both groups compared to the controls (721 +/- 42 microm), however, a significantly higher increase was observed in CO-group compared to AM-group (871 +/- 55 microm vs. 831 +/- 51 microm).

CONCLUSIONS

RCM evaluates significant histomorphological differences in superficial burns caused by combustion and ambustion. The term "superficial burn" should consider the underlying cause and thus supplemented by the term "combustion" or "ambustion."

Insight in human skin microcirculation using in vivo reflectance-mode confocal laser scanning microscopy

Reflectance-mode confocal laser scanning microscopy allows in vivo imaging of the human skin. We hypothesized that this high-resolution technique enables observation of dynamic changes of the cutaneous microcirculation. Twenty-two volunteers were randomly divided in two groups. Group 1 was exposed to local heating and group 2 to local cold stress. Confocal microscopy was performed prior t (0) (control), directly t (1) and 5 min t (2) after local temperature changes to evaluate quantitative blood cell flow, capillary loop diameter, and density of dermal capillaries. In group 1, blood flow increased at t (1) (75.82 +/- 2.86/min) and further at t (2) (84.09 +/- 3.39/min) compared to the control (61.09 +/- 3.21/min). The control capillary size was 9.59 +/- 0.25 microm, increased to 11.16 +/- 0.21 microm (t (1)) and 11.57 +/- 0.24 microm (t (2)). The dermal capillary density increased in t (1) (7.26 +/- 0.76/mm(2)) and t (2) (8.16 +/- 0.52/mm(2)), compared to the control (7.04 +/- 0.62/mm(2)). In group 2, blood flow decreased at t (1) (41.73 +/- 2.61/min) and increased at t (2) (83.27 +/- 3.29/min) compared to the control (60.73 +/- 2.90/min). The control capillary size was 9.55 +/- 0.25 microm, decreased at t (1) (7.78 +/- 0.26 microm) and increased at t (2) (11.38 +/- 0.26 microm). Capillary density decreased at t (1) (5.01 +/- 0.49/mm(2)) and increased at t (2) (7.28 +/- 0.53/mm(2)) compared to the control (7.01 +/- 0.52/mm(2)). Confocal microscopy is a sensitive and noninvasive imaging tool for characterizing and quantifying dynamic changes of cutaneous microcirculation on a histomorphological level.

Insight in microcirculation and histomorphology during burn shock treatment using in vivo confocal-laser-scanning microscopy

PURPOSE

Microcirculatory disturbances are well known during shock; however, the accompanied histomorphological alterations are widely unknown. We used high resolution confocal-laser-scanning microscopy for the evaluation of microcirculation and histomorphology during Burn Shock treatment.

METHODS

Confocal-laser-scanning microscopy was performed in 10 burn shock patients (4 women, 6 men; aged 40.6 +/- 11.4 years, burn extent >20% body surface area) initially and 24 hours after shock resuscitation. Ten matched hemodynamic stable burn intensive care unit patients served as controls. The following parameters were evaluated: quantitative blood cell flow, cell size of the granular layer, basal layer thickness, and epidermal thickness.

RESULTS

Quantitative blood cell flow in controls was 62.45 +/- 3.39 cells per minute. Burn shock significantly reduced blood cell flow to 37.27 +/- 3.64 cells per minute; fluid resuscitation effectively restored baseline blood flow (65.18 +/- 3.76 cells per minute) after 24 hours. Granular cell size was 793.61 +/- 41.58 microm(2) in controls vs 644.27 +/- 42.96 microm(2) during burn shock. Post resuscitation granular cell size measured 932.74 +/- 38.83 microm(2). Basal layer thickness was 14.84 +/- 0.59 microm in controls, 13.26 +/- 0.54 microm in burn patients at admission and before resuscitation, and 17.50 +/- 0.46 microm after resuscitation. Epidermal thickness in control patients was 49.60 +/- 2.36 microm, 37.83 +/- 2.47 microm in burn patients at admission and 69.50 +/- 3.18 microm after resuscitation.

CONCLUSIONS

Confocal-laser-scanning microscopy provides a noninvasive tool for simultaneous evaluation of microcirculation and tissue histomorphology. It may help to assess the adequacy of and response to resuscitation of burn patients early after trauma.

Monitoring of microcirculation in free transferred musculocutaneous latissimus dorsi flaps by confocal laser scanning microscopy--a promising non-invasive methodical approach

INTRODUCTION

For the survival of a microvascular tissue transfer, early detection of vascular complications is crucial. In vivo confocal laser scanning microscopy allows real-time, non-invasive evaluation of tissue microcirculation with a high cellular resolution. The aim of this study was to evaluate confocal laser scanning microscopy for early recognition of flap failure.

METHODS

Fourteen patients (ages: 40.2+/-12.4 years) were monitored postoperatively for a period of 24h following free microvascular M. latissimus dorsi transfer to the lower extremity using confocal laser scanning microscopy (Vivascope1500; Rochester; New York; USA). The following parameters were evaluated: quantitative blood-cell flow, diameter of capillary loops and minimal thickness of the epidermis.

RESULTS

Venous congestion was characterised by a decrease in blood-cell flow of up to 41%, accompanied by an increase of the diameter of capillary loops of up to 22% and the minimal thickness of the epidermis up to 32%. By contrast, arterial occlusion was clearly verified by a decrease in blood flow of up to 90%, accompanied by an insignificant change of both capillary loop size and epidermal thickness.

CONCLUSION

Confocal laser scanning microscopy appears to be a useful non-invasive tool for early recognition of flap failure during the monitoring of microsurgical tissue transfer prior to its clinical manifestation.