On the relationships between applied force, photography technique, and the quantification of bruise appearance

Examining the use of alternative light sources in medico-legal assessments of blunt-force trauma: a systematic review

The ability to analyze blunt-force trauma is crucial for deciphering valuable clues concerning mechanisms of injury and as evidence for medico-legal investigations. The use of alternate light sources (ALS) has been studied over the past decade, and is proposed to outperform conventional white light (CWL) during bruise assessments. In response to the growing interest of the technology worldwide, a systematic review of the literature was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) to address the ability of ALS to detect and visualize bruising. From an initial 4055 records identified, ten studies met the eligibly criteria and were selected for this review. Evaluation also included a novel framework, referred to as SPICOT, to further systematically assess both scientific evidence and risk of bias in forensic literature. Analysis reveals that narrowband wavelengths within in the infrared or ultraviolet spectral ranges do not significantly outperform CWL in visualizing or detecting bruising. However, wavelengths within the visible spectrum, particularly 415 nm combined with longpass or bandpass yellow filters, are more effective. However, the majority of selected studies only address the sensitivity of ALS, and therefore, results may only be considered valid when the location of a bruise is known. Further investigation is required to understand the specificity of ALS, in particular how the use of topical cosmetic products, previous wounds/scar-tissue, tattoos, moles and freckles may affect detection. The ethical concern regarding the interpretation of enhanced visualized trauma should also be considered in prospect discussions prior to implementing ALS into routine practice. Nevertheless, this review finds that narrowband ALS within the visible spectrum demonstrates potential for improved injury documentation, outperforming CWL in the detection and visualization of bruising.

A statistical model to predict the occurrence of blunt impact injuries on the human hand-arm system

Biomechanical limits based on pain thresholds ensure safety in workplaces where humans and cobots (collaborative robots) work together. Standardization bodies' decision to rely on pain thresholds stems from the assumption that such limits inherently protect humans from injury. This assumption has never been verified, though. This article reports on a study with 22 human subjects in which we studied injury onset in four locations of the hand-arm system using an impact pendulum. During the tests, the impact intensity was slowly increased over several weeks until a blunt injury, i.e., bruising or swelling, appeared in the body locations under load. A statistical model, which calculates injury limits for a given percentile, was developed based on the data. A comparison of our injury limits for the 25th percentile with existing pain limits confirms that pain limits provide suitable protection against impact injuries, albeit not for all body locations.

Pulsed Photothermal Radiometric Depth Profiling of Bruises by 532 nm and 1064 nm Lasers

Optical techniques are often inadequate in estimating bruise age since they are not sensitive to the depth of chromophores at the location of the bruise. To address this shortcoming, we used pulsed photothermal radiometry (PPTR) for depth profiling of bruises with two wavelengths, 532 nm (KTP laser) and 1064 nm (Nd:YAG laser). Six volunteers with eight bruises of exactly known and documented times of injury were enrolled in the study. A homogeneous part of the bruise was irradiated first with a 5 ms pulse at 532 nm and then with a 5 ms pulse at 1064 nm. The resulting transient surface temperature change was collected with a fast IR camera. The initial temperature-depth profiles were reconstructed by solving the ill-posed inverse problem using a custom reconstruction algorithm. The PPTR signals and reconstructed initial temperature profiles showed that the 532 nm wavelength probed the shallow skin layers revealing moderate changes during bruise development, while the 1064 nm wavelength provided additional information for severe bruises, in which swelling was present. Our two-wavelength approach has the potential for an improved estimation of the bruise age, especially if combined with modeling of bruise dynamics.

Quantitative Analysis of Tranexamic Acid Effects on Ecchymosis in Rhinoplasty

Background: Many methods have been described to reduce postoperative ecchymosis in rhinoplasty with tranexamic acid (TXA) remaining controversial. TXA remains a consideration for surgeons, however, may have serious side effects, including seizures, blood clots, and vision changes. Methods: A prospective study of primary rhinoplasty patients was performed from March 2019 to June 2019. TXA was used in 50 patients and postoperative ecchymosis was compared with 50 control patients. Adobe Photoshop was used to quantitate postoperative ecchymosis using multiple objective color scales. Results: One hundred subjects were enrolled in the study. Eighty-four females and 16 males were included. Photographs were taken on postoperative day 7. There were no significant differences among any of the Red, Green, Blue (RGB) and L*a*b* color subgroups with p > 0.05. There were no adverse events with TXA. Conclusions: In this study, TXA did not reduce postoperative ecchymosis in rhinoplasty when used both through intravenous and intraoperative injections.

The frequently dismissed importance of properly sampling skin bruises

The correct interpretation of skin lesions is a crucial issue in forensic medicine. Many macroscopic and microscopic vital reaction markers and molecules have been studied in the past years in order to estimate the timing of injuries. However, literature lacks information regarding how to perform sampling to obtain a more reliable and accurate response. The present study investigates 25 bruises and analyses the different histological asset in different areas (central or marginal) and the different layers (epidermis, dermis, hypodermis and muscle) of the wound. All wounds were sampled in several areas and analysed under a 200× magnification optical microscope, simply counting the degree of haemorrhaging (i.e hematic infiltration) visible in each optical field (0 = 0%-5%; 1 = 6%-25%; 2 = 26%-50%; 3 = 51%-75%; 4 = 76%-100%). All the injuries presented some kind of infiltration in at least one area, nonetheless only 56% of the wounds were infiltrated in the entirety of the areas. Finally, in 28% the dermal layer did not show any trace of infiltration. Therefore, considering such results it seems that depth or area of sampling of a bruise may largely influence the evaluation of vitality and hence of age of a wound. Though this may seem intuitive, no studies have examined this issue in depth.

Noninvasive Monitoring of Dynamical Processes in Bruised Human Skin Using Diffuse Reflectance Spectroscopy and Pulsed Photothermal Radiometry

We have augmented a recently introduced method for noninvasive analysis of skin structure and composition and applied it to monitoring of dynamical processes in traumatic bruises. The approach combines diffuse reflectance spectroscopy in visible spectral range and pulsed photothermal radiometry. Data from both techniques are analyzed simultaneously using a numerical model of light and heat transport in a four-layer model of human skin. Compared to the earlier presented approach, the newly introduced elements include two additional chromophores (β-carotene and bilirubin), individually adjusted thickness of the papillary dermal layer, and analysis of the bruised site using baseline values assessed from intact skin in its vicinity. Analyses of traumatic bruises in three volunteers over a period of 16 days clearly indicate a gradual, yet substantial increase of the dermal blood content and reduction of its oxygenation level in the first days after injury. This is followed by the emergence of bilirubin and relaxation of all model parameters towards the values characteristic for healthy skin approximately two weeks after the injury. The assessed parameter values and time dependences are consistent with existing literature. Thus, the presented methodology offers a viable approach for objective characterization of the bruise healing process.

Quantifying the Degree of Bruise Visibility Observed Under White Light and an Alternate Light Source

BACKGROUND

Documentation of injuries associated with abuse and assault has pivotal impacts on clinical and legal outcomes. Before this study, no reliable and valid tools to consistently document the clinical visibility of bruises existed. The purpose of this study was to systematically evaluate reliability and validity of the Bruise Visibility Scale for documenting bruises visualized in normal (white) light and the Absorption Visibility Scale for documenting bruises visualized using an alternate light source (ALS).

METHODS

Bruises were induced using a paintball on the upper arms of 157 participants stratified into six skin color categories. Bruises were visualized 21 times over 4 weeks under white light and 10 ALS wavelength/goggle color combinations. Bruise size was measured using a metric ruler; bruise color was measured using a spectrophotometer. Interrater reliability was calculated using kappa and intraclass correlations coefficients. Construct validity was evaluated using generalized linear mixed modeling of associations between bruise size and color with both visibility scales.

RESULTS

Interrater agreement for bruise detection was over 90% for all but two ALS wavelength/goggle combinations. Kappa values indicated adequate interrater agreement under white light (κ = 0.76) and ALS (κ = 0.78). The visibility scale intraclass correlation coefficients were .91 for normal light and .93 for ALS. Statistical modeling showed greater bruise size was associated with higher visibility using either scale, and greater contrast in color or lightness was associated with higher Bruise Visibility Scale values.

IMPLICATIONS FOR PRACTICE

Both visibility scales showed satisfactory reliability and validity. Forensic nurses can use the scales to consistently document bruises.