Experimental analyses of the retinal and subretinal haemorrhages accompanied by shaken baby syndrome/abusive head trauma using a dummy doll

An Update to Biomechanical and Biochemical Principles of Retinal Injury in Child Abuse

Abusive head trauma (AHT) is an extreme form of physical child abuse, a subset of which is shaken baby syndrome (SBS). While traumatic injury in children is most readily observed as marks of contusion on the body, AHT/SBS may result in internal injuries that can put the life of the child in danger. One pivotal sign associated with AHT/SBS that cannot be spotted with the naked eye is retinal injury (RI), an early sign of which is retinal hemorrhage (RH) in cases with rupture of the retinal vasculature. If not addressed, RI can lead to irreversible outcomes, such as visual loss. It is widely assumed that the major cause of RI is acceleration-deceleration forces that are repeatedly imposed on the patient during abusive shaking. Still, due to the controversial nature of this type of injury, few investigations have ever sought to delve into its biomechanical and/or biochemical features using realistic models. As such, our knowledge regarding AHT-/SBS-induced RI is significantly lacking. In this mini-review, we aim to provide an up-to-date account of the traumatology of AHT-/SBS-induced RI, as well as its biomechanical and biochemical features, while focusing on some of the experimental models that have been developed in recent years for studying retinal hemorrhage in the context of AHT/SBS.

Difficulties Encountered by Forensic Pathologists in Proving Abusive Head Trauma in Children: A Case Report

Shaken baby syndrome (SBS) or abusive head trauma (AHT) is one of the most common causes of death or serious neurological injury resulting from child abuse. AHT is defined as injury to the skull or intracranial contents of an infant or child younger than five years due to intentional abrupt impact and/or violent shaking. It is characterized by acute encephalopathy with subdural and retinal hemorrhages. We present a case of AHT that does not show the typical clinical triad. We describe one case of a pediatric patient addressed for forensic autopsy and where suspicion of AHT has arisen. The injury mechanism involved in the production of this syndrome and its clinical manifestation are sources of debate in forensic medicine. Thus, forensic pathologists must analyze all findings to determine SBS/AHT.

Clinical and Forensic Investigation Protocols for Diagnosing Abusive Head Trauma: A Literature Review

Abusive head trauma (AHT) represents a very serious global public health problem. Prevention of these episodes is essential to reduce the morbidity and mortality of this phenomenon. All healthcare professionals should be able to recognize the signs of abuse. However, diagnosis is very complex as the signs are often blurred and cannot be recognized with certainty without carrying out adequate instrumental investigations. It has been calculated that approximately one-third of AHT cases remain undetected and require more than one medical visit to be correctly interpreted and diagnosed. On the other hand, the literature has recently also emphasized the problems related to possible false diagnoses of abuse and the numerous family and personal repercussions that follow from this issue. For these reasons, correct and timely recognition is essential to avoid the risk of recurrence of AHT and to start proper forensic investigations, in order to identify the offender or exonerate a suspect. The present work explores the most recent evidence of recent years in the field of AHT diagnostics through a literature review. The purpose of this article is to provide forensic pathologists with clear tools for diagnosis based on the literature. To this end, the review suggests clinical and forensic protocols aimed at the timely diagnosis of AHT in order to prevent abuse from remaining undetected.

Quantifying the efficacy of protective eyewear in pediatric soccer-induced retinal injury

BACKGROUND

Ocular injury is common in children playing sports. Sports-related eye injuries, if severe enough, can lead to permanent vision impairment. Soccer, the most popular sport in the world, is a sport in which players rarely use protective eyewear. The purpose of this study was to determine how eye injuries are induced by a soccer ball impact and to evaluate whether eye protection influences the effects of impact.

METHODS

A finite element (FE) computer simulation was used to simulate soccer ball trauma on a model of the eye with and without eye protection. Protective eyewear of different materials (polycarbonate and acrylic) was modeled to investigate the optimal medium for eye protection. Stress and strain experienced by the eyeball was quantified by the FE computer simulation in each model.

RESULTS

Protective eyewear was found to be effective in lowering ocular stress and strain by absorbing and redirecting energy from the ball. Compared to the unprotected eye model, polycarbonate eyewear reduced the average stress the retina experienced by 61%, whereas the acrylic model reduced the average stress by 40%. Polycarbonate and acrylic eyewear also reduced the maximum strain experienced by the retina by 69% and 47%, respectively, reducing the severity of deformations of the eye on impact.

CONCLUSIONS

These findings suggest that wearing protective eyewear, especially when made of polycarbonate, can be an effective means of reducing injury-inducing retinal stress. The use of eye protection is thus recommended for pediatric patients participating in soccer.

Cerebral hemorrhage caused by shaking adult syndrome? Evidence from biomechanical analysis using 3D motion capture and finite element models

The present study combined three-dimensional (3D) motion capture with finite element simulation to reconstruct a real shaking adult syndrome (SAS) case and further explore the injury biomechanics of SAS. The frequency at which an adult male can shake the head of another person, head-shaking amplitude, and displacement curves was captured by the VICON 3D motion capture system. The captured shaking frequency and shaking curve were loaded on the total human model for safety (THUMS) head to simulate the biomechanical response of brain injury when a head was shaken in anterior-posterior, left-right, and left anterior-right posterior directions at frequencies of 4 Hz (Hz), 5 Hz, 6 Hz, and 7 Hz. The biomechanical response of the head on impact in the anterior, posterior, left, left anterior, and right posterior directions at the equivalent velocity of 6 Hz shaking was simulated. The violent shaking frequency of the adult male was 3.2-6.8 Hz; head shaking at these frequencies could result in serious cerebral injuries. SAS-related injuries have obvious directionality, and sagittal shaking can easily cause brain injuries. There was no significant difference between the brain injuries caused by shaking in the simulated frequency range (4-7 Hz). Impact and shaking at an equivalent velocity could cause brain injuries, though SAS more commonly occurred due to the cumulative deformation of brain tissue. Biomechanical studies of SAS should play a positive role in improving the accuracy of forensic identification and reducing this form of abuse and torture in detention or places of imprisonment.

Rapid Prediction of Retina Stress and Strain Patterns in Soccer-Related Ocular Injury: Integrating Finite Element Analysis with Machine Learning Approach

Soccer-related ocular injuries, especially retinal injuries, have attracted increasing attention. The mechanics of a flying soccer ball have induced abnormally higher retinal stresses and strains, and their correlation with retinal injuries has been characterized using the finite element (FE) method. However, FE simulations demand solid mechanical expertise and extensive computational time, both of which are difficult to adopt in clinical settings. This study proposes a framework that combines FE analysis with a machine learning (ML) approach for the fast prediction of retina mechanics. Different impact scenarios were simulated using the FE method to obtain the von Mises stress map and the maximum principal strain map in the posterior retina. These stress and strain patterns, along with their input parameters, were used to train and test a partial least squares regression (PLSR) model to predict the soccer-induced retina stress and strain in terms of distributions and peak magnitudes. The peak von Mises stress and maximum principal strain prediction errors were 3.03% and 9.94% for the frontal impact and were 9.08% and 16.40% for the diagonal impact, respectively. The average prediction error of von Mises stress and the maximum principal strain were 15.62% and 21.15% for frontal impacts and were 10.77% and 21.78% for diagonal impacts, respectively. This work provides a surrogate model of FE analysis for the fast prediction of the dynamic mechanics of the retina in response to the soccer impact, which could be further utilized for developing a diagnostic tool for soccer-related ocular trauma.

Finite Element Analysis of Soccer Ball-Related Ocular and Retinal Trauma and Comparison with Abusive Head Trauma

Purpose

Design

Participants

Methods

Main Outcome Measures

Results

Conclusions

Exploring the Vitreoretinal Interface: a Key Instigator of Unique Retinal Hemorrhage Patterns in Pediatric Head Trauma

Purpose

Various types of trauma can cause retinal hemorrhages in children, including accidental and nonaccidental head trauma. We used animal eyes and a finite element model of the eye to examine stress patterns produced during purely linear and angular accelerations, along with stresses attained during simulated repetitive shaking of an infant.

Methods

Using sheep and primate eyes, sclerotomy windows were created by removing the sclera, choroid, and retinal pigment epithelium to expose the retina. A nanofiber square was glued to a 5 mm² area of retina. The square was pulled and separated from vitreous while force was measured. A finite element model of the pediatric eye was used to computationally measure tension stresses during shaking.

Results

In both sheep and primate eyes, tension stress required for separation of retina from vitreous range from 1 to 5 kPa. Tension stress generated at the vitreoretinal interface predicted by the computer simulation ranged from 3 to 16 kPa during a cycle of shaking. Linear acceleration generated lower tension stress than angular acceleration. Angular acceleration generated maximal tension stress along the retinal vasculature. Linear acceleration produced more diffuse force distribution centered at the poster pole.

Conclusions

The finite element model predicted that tension stress attained at the retina during forcible shaking of an eye can exceed the minimum threshold needed to produce vitreoretinal separation as measured in animal eyes. Furthermore, the results show that movements that involve significant angular acceleration produce strong stresses localized along the vasculature, whereas linear acceleration produces weaker, more diffuse stress centered towards the posterior pole of the eye.

Charting the Globe: How Technologies Have Affected Our Understanding of Retinal Findings in Abusive Head Trauma/Shaken Baby Syndrome

Purpose: Ocular findings such as retinal hemorrhages are common in abusive head trauma (AHT). Binocular indirect ophthalmoscopy has been the standard for assessing the eyes of children who are victims of AHT. However, technological advances have changed our understanding of retinal findings in AHT.Methods: Literature review on AHT - retinal findings, imaging technologies, models of representation, and telemedicine applications.Results: Many studies suggest vitreoretinal traction from repetitive acceleration-deceleration shearing forces during shaking plays an important role in the development of retinal findings in AHT. This is further supported by different imaging modalities [optical coherence tomography (OCT); magnetic resonance imaging (MRI); fluorescein angiography (FA)] and models of representation (animal and mechanical models; finite element analysis).Conclusion: Emerging technologies have augmented our diagnostic abilities, enhanced our understanding regarding the pathophysiology of retinal findings, and strengthened the link between vitreoretinal traction and ocular pathology in AHT. Telemedicine is also starting to play an important role in AHT.

Determining the Tractional Forces on Vitreoretinal Interface Using a Computer Simulation Model in Abusive Head Trauma

PURPOSE

Abusive head trauma (AHT) is the leading cause of infant death and long-term morbidity from injury. The ocular consequences of AHT are controversial, and the pathophysiology of retinal research findings is still not clearly understood. It has been postulated that vitreoretinal traction plays a major role in the retinal findings. A computer simulation model was developed to evaluate the vitreoretinal traction and determine whether the distribution of forces in different layers and locations of the retina can explain the patterns of retinal hemorrhage (RH) seen in AHT.

DESIGN

Computer simulation model study.

METHODS

A computer simulation model of the pediatric eye was developed to evaluate preretinal, intraretinal, and subretinal stresses during repetitive shaking. This model was also used to examine the forces applied to various segments along blood vessels.

RESULTS

Calculated stress values from the computer simulation ranged from 3-16 kPa at the vitreoretinal interface through a cycle of shaking. Maximal stress was observed at the periphery of the retina, corresponding to areas of multiple vessel bifurcations, followed by the posterior pole of the retina. Stress values were similar throughout all 3 layers of the retina (preretinal, intraretinal, and subretinal layers).

CONCLUSIONS

Ocular manifestations from AHT revealed unique retinal characteristics. The model predicted stress patterns consistent with the diffuse retinal hemorrhages (RH) typically found in the posterior pole and around the peripheral retina in AHT. This computer model demonstrated that similar stress forces were produced in different layers of the retina, consistent with the finding that retinal hemorrhages are often found in multiple layers of the retina. These data can help explain the RH patterns commonly found in AHT.

Modeling of inflicted head injury by shaking trauma in children: what can we learn? : Part II: A systematic review of mathematical and physical models

Various types of complex biomechanical models have been published in the literature to better understand processes related to inflicted head injury by shaking trauma (IHI-ST) in infants. In this systematic review, a comprehensive overview of these models is provided. A systematic review was performed in MEDLINE and Scopus for articles using physical (e.g. dolls) and mathematical (e.g. computer simulations) biomechanical models for IHI-ST. After deduplication, the studies were independently screened by two researchers using PRISMA methodology and data extracted from the papers is represented in a “7-steps description”, addressing the different processes occurring during IHI-ST. Eleven papers on physical models and 23 papers on mathematical models were included after the selection process. In both categories, some models focus on describing gross head kinematics during IHI-ST events, while others address the behavior of internal head- and eye structures in various levels of detail. In virtually all physical and mathematical models analyzed, injury thresholds are derived from scaled non-infant data. Studies focusing on head kinematics often use injury thresholds derived from impact studies. It remains unclear to what extent these thresholds reflect the failure thresholds of infant biological material. Future research should therefore focus on investigating failure thresholds of infant biological material as well as on possible alternative injury mechanism and alternative injury criteria for IHI-ST.

Simulation-based research to improve infant health outcomes: Using the infant simulator to prevent infant shaking

Simulation is a technique that creates a situation or environment to allow persons to experience a representation of a real event for the purpose of practice, learning, evaluation, testing, or to gain understanding of systems or human actions. We will first provide an introduction to simulation in healthcare and describe the two types of simulation-based research (SBR) in the pediatric population. We will then provide an overview of the use of SBR to improve health outcomes for infants in health care settings and to improve parent-child interactions using the infant simulator. Finally, we will discuss previous and future research using simulation to reduce morbidity and mortality from abusive head trauma, the most common cause of traumatic death in infancy.

Administration of anticonvulsive rescue medication in children-discrepancies between parents' self-reports and limited practical performance

Quality of parents' performance in administering anticonvulsive rescue medication to their children suffering from seizures is unknown. After obtaining ethical approval, we used a questionnaire to ask parents of children with seizures, who had been prescribed rescue medications, about their experience in administering those. To assess the frequency of actually committed drug-handling errors, we let them administer rescue medications to dummy dolls. An expert panel rated the clinical risk of handling errors from "1" (lowest) to "6" (highest). Eighty-one parents completed the study. In the questionnaire, 85 % (100 %) of parents that already conducted rectal (buccal) administration reported that they had never experienced problems. The number of rectal administrations with at least one handling error (97 %, 58/60) was higher than in buccal administration (58 %; 14/24; p < 0.001). According to logistic regressions, previous use of rescue medication was not a predictor of the number of committed errors per process (n. s.). All errors were rated with a high clinical risk (class 4-6).

CONCLUSION

By observing parents' administration of rescue medication to dummy dolls, we found a high frequency of clinically relevant drug-handling errors. Most parents, however, self-reported to have never experienced problems while administering rescue medications to their children.

WHAT IS KNOWN

• For seizures with duration of more than 5 min, the administration of anticonvulsive rescue medication is recommended. • Outside the hospital, the administration of rescue medication to children is performed most frequently by their parents. What is New: • Most of the parents reported that they had never experienced problems in handling anticonvulsive rescue medication. • But in the observed drug-handling performances, identified errors committed by parents were alarmingly frequent and pose a high clinical risk according to an expert panel.

Evaluation of knowledge regarding shaken baby syndrome among parents and medical staff

BACKGROUND

Shaken baby syndrome (SBS), currently functioning as abusive head trauma (AHT), is a form of violence against children mainly under 2 years of age. The number of SBS might be underestimated, as many cases of violence remain unreported. The aim of the study was the evaluation of the state knowledge of the SBS phenomenon, its scale and diagnostic methods among parents, medical staff and medical students.

METHODS

A total of 639 people were examined: 39% of parents, 32.5% of medical staff members, and 28.5% of medical students; 82% were women. The average age was 34.9±9.78 years, and 70% of them had children. The research tool was an anonymous survey. The 34 questions concerned numerous aspects of violence against children as well as knowledge about SBS.

RESULTS

According to 90% of the interviewees shaking a baby may be dangerous but 43% have never heard about shaken baby syndrome. Eighty-eight percent of responders stated that "SBS is a form of violence," but only 57% realize that one-time shaking can lead to death and only 19% indicated men as aggressors. Sixteen percent of medical staff members did not know how long it takes for the consequences of shaking a baby to be revealed.

CONCLUSIONS

Majority of the medical staff members working with children have never heard about SBS. Only half of the surveyed understands the connection of shaking with vision loss or child's death. Among the long-term consequences of shaking a baby, the greatest knowledge concerns emotional consequences of shaking.

Update on abusive head trauma

PURPOSES OF REVIEW

This article provides an update on abusive head trauma (AHT), focusing on new developments most salient to the emergency medicine clinician, including epidemiology, clinical recognition, diagnostic work-up, management of neurologic injury, and public health implications.

RECENT FINDINGS

The recent literature has focused on honing the clinician's ability to recognize AHT and its immediate sequelae, to more accurately distinguish between abusive and accidental head injuries by patterns of neuroimaging and retinal hemorrhages, and to appreciate the long-term impacts. Specifically, both a clinical prediction rule and biomarker show promise, and new research advocates for the early identification of subclinical seizures as well as cervical spine injuries.

SUMMARY

The emergency medicine provider must be able to recognize and manage children who may have AHT and to appreciate when the diagnostic findings warrant consultation with a child protection team. These authors summarize the recent and notable advances in our understanding of AHT.