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Sokoloff M, Feldman KW, Levin AV, Rockter A, Armijo-Garcia V, Musick M, Weeks K, Haney SB, Marinello M, Herman BE, Frazier TN, Carroll CL, Hymel KP. Retinal hemorrhage variation in inertial versus contact head injuries. CHILD ABUSE & NEGLECT 2024; 149:106606. [PMID: 38134727 DOI: 10.1016/j.chiabu.2023.106606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 12/07/2023] [Accepted: 12/13/2023] [Indexed: 12/24/2023]
Abstract
BACKGROUND Abusive head trauma (AHT) is frequently accompanied by dense/extensive retinal hemorrhages to the periphery with or without retinoschisis (complex retinal hemorrhages, cRH). cRH are uncommon without AHT or major trauma. OBJECTIVE The study objectives were to determine whether cRH are associated with inertial vs. contact mechanisms and are primary vs. secondary injuries. PARTICIPANTS AND SETTING This retrospective study utilized a de-identified PediBIRN database of 701 children <3-years-old presenting to intensive care for head trauma. Children with motor vehicle related trauma and preexisting brain abnormalities were excluded. All had imaging showing head injury and a dedicated ophthalmology examination. METHODS Contact injuries included craniofacial soft tissue injuries, skull fractures and epidural hematoma. Inertial injuries included acute impairment or loss of consciousness and/or bilateral and/or interhemispheric subdural hemorrhage. Abuse was defined in two ways, by 1) predetermined criteria and 2) caretaking physicians/multidisciplinary team's diagnostic consensus. RESULTS PediBIRN subjects with cRH frequently experienced inertial injury (99.4 % (308/310, OR = 53.74 (16.91-170.77)) but infrequently isolated contact trauma (0.6 % (2/310), OR = 0.02 (0.0004-0.06)). Inertial injuries predominated over contact trauma among children with cRH sorted AHT by predetermined criteria (99.1 % (237/239), OR = 20.20 (6.09-67.01) vs 0.5 % (2/339), OR = 0.04 (0.01-0.17)). Fifty-nine percent of patients with cRH, <24 h altered consciousness, and inertial injuries lacked imaging evidence of brain hypoxia, ischemia, or swelling. CONCLUSIONS cRH are significantly associated with inertial angular acceleration forces. They can occur without brain hypoxia, ischemia or swelling suggesting they are not secondary injuries.
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Affiliation(s)
- Michael Sokoloff
- Department of Pediatrics, Pediatric Intensive Care, Sacred Heart Children's Hospital, Spokane, WA, United States of America.
| | - Kenneth W Feldman
- Department of Pediatrics, Seattle Children's, University of Washington's Harborview Medical Center, Seattle, WA, United States of America; Department of Pediatrics, Safe Child and Adolescent Network, Seattle Children's, Seattle, WA, United States of America.
| | - Alex V Levin
- Department of Ophthalmology, Flaum Eye Institute, University of Rochester, Rochester, NY, United States of America.
| | - Adam Rockter
- University of Rochester School of Medicine, Rochester, NY, United States of America.
| | - Veronica Armijo-Garcia
- Department of Pediatrics, University of Texas Health Sciences Center at San Antonio, San Antonio, TX, United States of America.
| | - Matthew Musick
- Department of Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston, TX, United States of America.
| | - Kerri Weeks
- Department of Pediatrics, University of Kansas School of Medicine, Wichita, KS, United States of America.
| | - Suzanne B Haney
- Department of Pediatrics, University of Nebraska Medical Center, Children's Hospital and Medical Center, Omaha, NE, United States of America.
| | - Mark Marinello
- Department of Pediatrics, Children's Hospital of Richmond at VCU, Richmond, VA, United States of America.
| | - Bruce E Herman
- Department of Pediatrics, University of Utah School of Medicine, Primary Children's Hospital, Salt Lake City, UT, United States of America.
| | - Terra N Frazier
- Department of Pediatrics, Children's Mercy Hospital, Kansas City, MO, United States of America.
| | - Christopher L Carroll
- Department of Pediatrics, Connecticut Children's Medical Center, Hartford, CT, United States of America.
| | - Kent P Hymel
- Department of Pediatrics, Penn State College of Medicine, Hershey, PA, United States of America
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Schiks LAH, Dankelman J, Loeve AJ. Inflicted head-injury by shaking-trauma in infants: the importance of spatiotemporal variations of the head's rotation center. Sci Rep 2023; 13:15226. [PMID: 37709812 PMCID: PMC10502057 DOI: 10.1038/s41598-023-42373-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 09/09/2023] [Indexed: 09/16/2023] Open
Abstract
Inflicted head injury by shaking trauma (IHI-ST) in infants is a type of abusive head trauma often simulated computationally to investigate causalities between violent shaking and injury. This is commonly done with the head's rotation center kept fixed over time. However, due to the flexibility of the infant's neck and the external shaking motion imposed by the perpetrator it is unlikely that the rotation center is static. Using a test-dummy, shaken by volunteers, we demonstrated experimentally that the location of the head's rotation center moves considerably over time. We further showed that implementation of a spatiotemporal-varying rotation center in an improved kinematic model resulted in strongly improved replication of shaking compared to existing methods. Hence, we stress that the validity of current infant shaking injury risk assessments and the injury thresholds on which these assessments are based, both often used in court cases, should be re-evaluated.
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Affiliation(s)
- L A H Schiks
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - J Dankelman
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - A J Loeve
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands.
- Co van Ledden Hulsebosch Center for Forensic Science and Medicine, Amsterdam, The Netherlands.
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Chen D, Liu X, Sun X, Liu Y, Geng X, Huo H, Tang M, Tang Z, Dong Y, Wang J, Qiao X, Du X, Guo J, Elsheikh A, Fan Y. Experimental evidence to understand mechanical causes of retinal detachment following blunt trauma. Exp Eye Res 2023:109552. [PMID: 37356538 DOI: 10.1016/j.exer.2023.109552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/10/2023] [Accepted: 06/22/2023] [Indexed: 06/27/2023]
Abstract
PURPOSE This study aimed to perform an in vitro experiment to simulate retinal detachment caused by blunt impact, and provide experimental evidence to understand mechanical causes of traumatic retinal detachment. METHODS The experiment was conducted on twenty-two fresh porcine eyes using a bespoke pendulum testing device at two energy levels (0.1J for low energy and 1.0J for high energy). We examined dynamic forces and mechanical responses to the impact, including global deformations, intraocular pressure changes and the energy absorption. Another set of twenty-two eyes underwent pathological examination immediately after being subjected to blunt impact. Twelve additional intact eyes were examined as controls. All pathological sections were scored to indicate whether retinal detachment had occurred. RESULTS A dynamic variation in intraocular pressure was detected following impact and exhibited an approximate sinusoidal oscillation-attenuation profile. The peaks of impact force were 12.9 ± 1.9 N at low-energy level and 34.8 ± 9.8 N at high-energy level, showing a significant difference (p < 0.001). The positive and negative peaks of intraocular pressure were 149.4 ± 18.9 kPa and -10.9 ± 7.2 kPa at low-energy level, and 274.5 ± 55.2 kPa and -35.7 ± 23.7 kPa at high-energy level, showing significant differences (p < 0.001 for both levels). Retinal detachments were observed in damaged eyes while few detachments were found in control eyes. The occurrence rate of retinal detachment differed significantly (p < 0.05) between the high- and low-energy impact groups. CONCLUSIONS This study provided experimental evidence that shockwaves produced by blunt trauma break the force equilibrium and lead to the oscillation and negative pressure, which mainly contribute to traumatic retinal detachment.
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Affiliation(s)
- Duo Chen
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Xiaoyu Liu
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China.
| | - Xiaona Sun
- School of Engineering, University of Liverpool, Liverpool, L69 3GH, UK
| | - Yanwu Liu
- Department of Emergency, Aviation General Hospital, Chaoyang District, Beijing, 100012, China
| | - Xiaoqi Geng
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Hongqiang Huo
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Min Tang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Zhili Tang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Ying Dong
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Jinghui Wang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Xiaofeng Qiao
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Xin Du
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Jieyi Guo
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Ahmed Elsheikh
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China; School of Engineering, University of Liverpool, Liverpool, L69 3GH, UK.
| | - Yubo Fan
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China; Department of Ophthalmology, Beijing Children's Hospital, Beijing, 100034, China.
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Pediatric abusive head trauma: visual outcomes, evoked potentials, diffusion tensor imaging, and relationships to retinal hemorrhages. Doc Ophthalmol 2023:10.1007/s10633-023-09927-w. [PMID: 36881212 DOI: 10.1007/s10633-023-09927-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 02/06/2023] [Indexed: 03/08/2023]
Abstract
PURPOSE Function and anatomy of the visual system were evaluated in children with abusive head trauma (AHT). The relationships between retinal hemorrhages at presentation were examined with outcome measures. METHODS Retrospective review of data in children with AHT for 1) visual acuity at last follow-up, 2) visual evoked potentials (VEP) after recovery, 3) diffusion metrics of white matter tracts and grey matter within the occipital lobe on diffusion tensor imaging (DTI), and 4) patterns of retinal hemorrhages at presentation. Visual acuity was converted into logarithm of minimum angle of resolution (logMAR) after correction for age. VEPs were also scored by objective signal-to-noise ratio (SNR). RESULTS Of 202 AHT victims reviewed, 45 met inclusion criteria. Median logMAR was reduced to 0.8 (approximately 20/125 Snellen equivalent), with 27% having no measurable vision. Thirty-two percent of subjects had no detectable VEP signal. VEPs were significantly reduced in subjects initially presenting with traumatic retinoschisis or hemorrhages involving the macula (p < 0.01). DTI tract volumes were decreased in AHT subjects compared to controls (p < 0.001). DTI metrics were most affected in AHT victims showing macular abnormalities on follow-up ocular examination. However, DTI metrics were not correlated with visual acuity or VEPS. There was large inter-subject variability within each grouping. DISCUSSION Mechanisms causing traumatic retinoschisis, or traumatic abnormalities of the macula, are associated with significant long-term visual pathway dysfunction. AHT associated abnormalities of the macula, and visual cortical pathways were more fully captured by VEPs than visual acuity or DTI metrics.
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Luo RH, Tram NK, Parekh AM, Puri R, Reilly MA, Swindle-Reilly KE. The Roles of Vitreous Biomechanics in Ocular Disease, Biomolecule Transport, and Pharmacokinetics. Curr Eye Res 2023; 48:195-207. [PMID: 35179421 DOI: 10.1080/02713683.2022.2033271] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
PURPOSE The biomechanical properties of the vitreous humor and replication of these properties to develop substitutes for the vitreous humor have rapidly become topics of interest over the last two decades. In particular, the behavior of the vitreous humor as a viscoelastic tissue has been investigated to identify its role in a variety of processes related to biotransport, aging, and age-related pathologies of the vitreoretinal interface. METHODS A thorough search and review of peer-reviewed publications discussing the biomechanical properties of the vitreous humor in both human and animal specimens was conducted. Findings on the effects of biomechanics on vitreoretinal pathologies and vitreous biotransport were analyzed and discussed. RESULTS The pig and rabbit vitreous have been found to be most mechanically similar to the human vitreous. Age-related liquefaction of the vitreous creates two mechanically unique phases, with an overall effect of softening the vitreous. However, the techniques used to acquire this mechanical data are limited by the in vitro testing methods used, and the vitreous humor has been hypothesized to behave differently in vivo due in part to its swelling properties. The impact of liquefaction and subsequent detachment of the vitreous humor from the posterior retinal surface is implicated in a variety of tractional pathologies of the retina and macula. Liquefaction also causes significant changes in the biotransport properties of the eye, allowing for significantly faster movement of molecules compared to the healthy vitreous. Recent developments in computational and ex vivo models of the vitreous humor have helped with understanding its behavior and developing materials capable of replacing it. CONCLUSIONS A better understanding of the biomechanical properties of the vitreous humor and how these relate to its structure will potentially aid in improving clinical metrics for vitreous liquefaction, design of biomimetic vitreous substitutes, and predicting pharmacokinetics for intravitreal drug delivery.
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Affiliation(s)
- Richard H Luo
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Nguyen K Tram
- Center for Regenerative Medicine, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Ankur M Parekh
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, USA
| | - Raima Puri
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Matthew A Reilly
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.,Department of Ophthalmology and Visual Sciences, The Ohio State University, Columbus, OH, USA
| | - Katelyn E Swindle-Reilly
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.,William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, USA.,Department of Ophthalmology and Visual Sciences, The Ohio State University, Columbus, OH, USA
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Christian CW, Binenbaum G. The eye in child abuse. Childs Nerv Syst 2022; 38:2335-2344. [PMID: 35871261 DOI: 10.1007/s00381-022-05610-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 07/11/2022] [Indexed: 11/30/2022]
Abstract
Child physical abuse may result in a range of injuries to the globe and surrounding tissues. These injuries have varying degrees of specificity for abuse, and no pattern of injury is unique to abuse. Easily overlooked eye injuries in non-ambulatory infants often portend more severe abuse and require careful evaluation for occult injury when they are unexplained. Retinal hemorrhages are most often a sign of significant trauma and the severity of the hemorrhages generally parallels the severity of neurological trauma. Ophthalmologists contribute important data that more easily distinguish medical disease from trauma, but caution is needed in differentiating accidental from inflicted trauma. This distinction requires careful consideration of the complete clinical data and occasionally on additional law enforcement or child welfare investigation.
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Affiliation(s)
- Cindy W Christian
- The Children's Hospital of Philadelphia, 3500 Civic Center Blvd, Philadelphia, PA, 19104, USA.
- Department of Pediatrics, The Perelman School of Medicine at The University of Pennsylvania, Philadelphia, USA.
| | - Gil Binenbaum
- The Children's Hospital of Philadelphia, 3500 Civic Center Blvd, Philadelphia, PA, 19104, USA
- Department of Ophthalmology, The Perelman School of Medicine at The University of Pennsylvania, Philadelphia, USA
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Phillips JD, Hwang ES, Morgan DJ, Creveling CJ, Coats B. Structure and mechanics of the vitreoretinal interface. J Mech Behav Biomed Mater 2022; 134:105399. [PMID: 35963021 PMCID: PMC9552593 DOI: 10.1016/j.jmbbm.2022.105399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 07/17/2022] [Accepted: 07/24/2022] [Indexed: 12/24/2022]
Abstract
Vitreoretinal mechanics plays an important role in retinal trauma and many sight-threatening diseases. In age-related pathologies, such as posterior vitreous detachment and vitreomacular traction, lingering vitreoretinal adhesions can lead to macular holes, epiretinal membranes, retinal tears and detachment. In age-related macular degeneration, vitreoretinal traction has been implicated in the acceleration of the disease due to the stimulation of vascular growth factors. Despite this strong mechanobiological influence on trauma and disease in the eye, fundamental understanding of the mechanics at the vitreoretinal interface is limited. Clarification of adhesion mechanisms and the role of vitreoretinal mechanics in healthy eyes and disease is necessary to develop innovative treatments for these pathologies. In this review, we evaluate the existing literature on the structure and function of the vitreoretinal interface to gain insight into age- and region-dependent mechanisms of vitreoretinal adhesion. We explore the role of vitreoretinal adhesion in ocular pathologies to identify knowledge gaps and future research areas. Finally, we recommend future mechanics-based studies to address the critical needs in the field, increase fundamental understanding of vitreoretinal mechanisms and disease, and inform disease treatments.
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Affiliation(s)
- Joseph D Phillips
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Eileen S Hwang
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, United States
| | - Denise J Morgan
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, United States
| | | | - Brittany Coats
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, United States.
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Shokrollahi Y, Dong P, Kaya M, Suh DW, Gu L. Rapid Prediction of Retina Stress and Strain Patterns in Soccer-Related Ocular Injury: Integrating Finite Element Analysis with Machine Learning Approach. Diagnostics (Basel) 2022; 12:diagnostics12071530. [PMID: 35885436 PMCID: PMC9319813 DOI: 10.3390/diagnostics12071530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/15/2022] [Accepted: 06/20/2022] [Indexed: 11/16/2022] Open
Abstract
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.
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Affiliation(s)
- Yasin Shokrollahi
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA; (Y.S.); (P.D.); (M.K.)
| | - Pengfei Dong
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA; (Y.S.); (P.D.); (M.K.)
| | - Mehmet Kaya
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA; (Y.S.); (P.D.); (M.K.)
| | - Donny W. Suh
- Gavin Herbert Eye Institute (GHEI), University of California at Irvine, Irvine, CA 92697, USA;
| | - Linxia Gu
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA; (Y.S.); (P.D.); (M.K.)
- Correspondence:
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Yaghoubi V, Setayeshnasab H, Mosaddegh P, Kadkhodaei M. A stochastic approach to estimate intraocular pressure and dynamic corneal responses of the cornea. J Mech Behav Biomed Mater 2022; 130:105210. [PMID: 35397406 DOI: 10.1016/j.jmbbm.2022.105210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 03/17/2022] [Accepted: 03/26/2022] [Indexed: 11/15/2022]
Abstract
IntraOcular Pressure (IOP) is one of the most informative factors for monitoring the eye-health. This is usually measured by tonometers. However, the outputs of the tonometers depend on the physical and geometrical properties of the cornea. Therefore, the common practice is to develop a numerical model to generate some correction factors. The main challenge here is the accuracy and efficiency of a numerical model in predicting the IOP and Dynamic Corneal Response (DCR) of each patient. This study addresses this issue by developing a two-step surrogate model based on adaptive sparse Polynomial Chaos Expansion (PCE) for fast and accurate prediction of the IOP. In this regard, first, an FE model of the cornea has been developed to predict the DCR parameters. This FE model has been replaced with a PCE-based surrogate model to speed up the simulation step. The uncertainties in the geometry and material model of the cornea have been propagated through the surrogate model to estimate the distributions of the DCR parameters. In the second step, the combination of DCR parameters and the input parameters provide a proper parameter space for developing an efficient data-driven PCE model to predict the IOP. Moreover, sensitivity analysis by using PCE-based Sobol indices has been performed. The results demonstrate the accuracy and efficiency of the proposed method in predicting the IOP. Sensitivity analysis revealed that IOP measurement was influenced mostly by deflection amplitude and applanation time. The analysis indicates the importance of the interactions between the parameters.
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Affiliation(s)
- Vahid Yaghoubi
- Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, 84156-83111, Iran; Structural Integrity & Composites, Faculty of Aerospace Engineering, Delft University of Technology, 2629 HS, Delft, Netherlands.
| | - Hamed Setayeshnasab
- Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, 84156-83111, Iran
| | - Peiman Mosaddegh
- Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, 84156-83111, Iran
| | - Mahmoud Kadkhodaei
- Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, 84156-83111, Iran
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Finite Element Analysis of the Epiretinal Membrane Contraction. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12052623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
The epiretinal membrane is a thin sheet of fibrous tissue that can form over the macular area of the retina, and may result in the loss of visual acuity or metamorphopsia, due to superficial retinal folds. A vitrectomy surgery, the current treatment procedure for this pathology, is only performed after symptoms are present. However, sometimes the patients do not present any vision improvements after the surgery. The use of computational methods for a patient-specific biomechanical analysis can contribute to better understanding the mechanisms behind the success or failure of a vitrectomy. Using medical data from two patients who underwent a vitrectomy, one with substantial improvements and another with no improvements, an analysis of the retinal displacement due to the contraction of the epiretinal membrane was performed. Our results suggest a causal effect between the magnitude of the retinal displacements caused by the epiretinal membrane contraction and the outcome of the vitrectomy procedure.
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Moskwa R, Todeschi J, Wiedemann-Fode A, Stella I, Joud A, Klein O. Ophthalmological lesions in shaken baby syndrome: a retrospective analysis of 133 consecutive cases (1992-2018). Neurochirurgie 2022; 68:367-372. [PMID: 35150727 DOI: 10.1016/j.neuchi.2022.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 01/16/2022] [Accepted: 01/20/2022] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Shaken Baby Syndrome (SBS) is a non-accidental head trauma in which shaking causes cranio-cerebral lesions. Shaking can lead to ophthalmologic lesions such as retinal hemorrhage (RH). The aim of the present study was to compare our long-term results in to the literature data. PATIENTS AND METHODS This study was a single-center retrospective descriptive analysis of 133 consecutive SBS cases (1992 - 2018). Only seniors in ophthalmology were authorized to perform these examinations. We studied type of lesion (retinal, intra-vitreal, papilledema), location (uni- or bi-lateral), and correlation with gender and age. Infants with a traumatic context without suspicion of child abuse were excluded. RESULTS Mean age at diagnosis was 131 days (range, 14 days - 10 months). Boys accounted for 72.2% of the population. The prevalence of ophthalmologic lesions was 70.3%. 94.4% were RH; intra-vitreous hemorrhage (6.7%) and papilledema (11.1%) were less frequent. Lesions were bilateral in 81.1% of cases. Retinal lesions were classified in terms of location. Macular involvement was diagnosed in 8.2% of cases. 18.8% of retinal lesions could not be classified because of lack of precision in the ophthalmology report. The prevalence of ophthalmic lesions was higher for children aged over 6 months: 80%. CONCLUSION This series highlighted a high rate of ophthalmic lesions in SBS, with a high rate of bilateral involvement. RH was the most frequent lesion. RH in a context of subdural hematoma is a strong argument in favor of SBS. The forensic implications are that rigorous ophthalmologic examination by a senior practitioner is mandatory.
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Affiliation(s)
- Rémy Moskwa
- Department of Ophthalmology, Mercy Regional Hospital, Ars-Laquenexy, France; Service of Pediatric Neurosurgery, Children's Hospital, Nancy University Hospital, Université de Lorraine, France
| | - Julien Todeschi
- Service of Pediatric Neurosurgery, Children's Hospital, Nancy University Hospital, Université de Lorraine, France
| | - Arnaud Wiedemann-Fode
- Pediatric Intensive Care Unit, Children's Hospital, Nancy University Hospital, INSERM Unit 1256 N-GERE, Université de Lorraine, France
| | - Irene Stella
- Service of Pediatric Neurosurgery, Children's Hospital, Nancy University Hospital, Université de Lorraine, France
| | - Anthony Joud
- Service of Pediatric Neurosurgery, Children's Hospital, Nancy University Hospital, Université de Lorraine, France
| | - Olivier Klein
- Service of Pediatric Neurosurgery, Children's Hospital, Nancy University Hospital, Université de Lorraine, France.
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Abstract
ABSTRACT We describe 3 infants with skull fractures that involved more than 1 skull bone. On further evaluation, 2 of the 3 infants had additional fractures at other sites of the body and the third infant had concerning bruising of the face. Although an accidental mechanism of injury was initially given as the history in each case, law enforcement investigations led all 3 fathers to confess to crushing their infants' skulls out of frustration. These crushes were caused by their arms or hands. Bilateral skull fractures or those involving more than 1 skull bone can be seen in falls as well as in crush injuries. A crush-like pattern of injury, in the absence of a clear and plausible accidental mechanism, should raise concerns for possible physical abuse especially in nonambulatory infants.
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Affiliation(s)
- Emily C B Brown
- From the Department of Pediatrics, Seattle Children's Hospital, University of Washington, Seattle, WA
| | | | - Jeffrey P Otjen
- Department of Radiology, Seattle Children's Hospital, University of Washington, Seattle, WA
| | - Kenneth W Feldman
- From the Department of Pediatrics, Seattle Children's Hospital, University of Washington, Seattle, WA
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Gjerde H, Mantagos IS. Charting the Globe: How Technologies Have Affected Our Understanding of Retinal Findings in Abusive Head Trauma/Shaken Baby Syndrome. Semin Ophthalmol 2021; 36:205-209. [PMID: 33793387 DOI: 10.1080/08820538.2021.1890150] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
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.
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Affiliation(s)
- Harald Gjerde
- Department of Ophthalmology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Iason S Mantagos
- Department of Ophthalmology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA
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Suh DW, Song HH, Mozafari H, Thoreson WB. Determining the Tractional Forces on Vitreoretinal Interface Using a Computer Simulation Model in Abusive Head Trauma. Am J Ophthalmol 2021; 223:396-404. [PMID: 32663454 DOI: 10.1016/j.ajo.2020.06.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 06/13/2020] [Accepted: 06/16/2020] [Indexed: 10/23/2022]
Abstract
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.
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Modeling Hypertension as a Contributor to Retinal Hemorrhaging from Abusive Head Trauma. JOURNAL OF HEALTHCARE ENGINEERING 2020; 2020:4714927. [PMID: 32566113 PMCID: PMC7256766 DOI: 10.1155/2020/4714927] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 12/31/2019] [Accepted: 01/20/2020] [Indexed: 12/05/2022]
Abstract
Retinal hemorrhaging (RH) is indicative and prevalent in abusive head trauma (AHT)—yet the direct cause of the RH from AHT is unknown. Our hypothesis is that RH in AHT is the combination of shaking forces and hypertension. This combination of effects explains why RH is not normally observed in common childhood accidents but is nearly exclusively observed in AHT. An experimental model using porcine eyes was designed to ascertain the required pressure change for sudden RH and, via a computer model, the subsequent stress increase in blood vessels. The porcine eyes were cannulated via the maxillary artery and pressurized until perfusion and RH were observed. Fluid was injected into the head with a computer-controlled continuous flow syringe pump; video of the fundus was recorded during perfusion; and the pressure of the fluid entering the eye was recorded as well. A computer model was created in COMSOL to simulate loading from hypertension, shaking, and the combination of the forces. This model was validated via experimental data collected from the porcine model. It was found that hypertension or shaking alone did not cause an increase in stress required to cause RH. But when the loading of shaking and hypertension was combined, as would occur in AHT, the stress increases were greater than those extrapolated from the porcine model and would cause RH.
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Biomechanism of resistance to retinal injury in woodpecker’s eyes. SCIENCE CHINA-LIFE SCIENCES 2020; 63:592-598. [DOI: 10.1007/s11427-019-1664-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 12/01/2019] [Indexed: 10/24/2022]
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Kelly JP, Feldman K, Wright J, Ganti S, Metz JB, Weiss A. Retinal and visual function in infants with non-accidental trauma and retinal hemorrhages. Doc Ophthalmol 2020; 141:111-126. [PMID: 32052259 DOI: 10.1007/s10633-020-09756-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 02/06/2020] [Indexed: 11/27/2022]
Abstract
PURPOSE To investigate retinal function and visual outcomes in infants with retinal hemorrhages due to non-accidental trauma (NAT). METHODS This is a retrospective review of full-field or multifocal electroretinogram (ERG) recordings, visual acuity in log minimum angle of resolution (logMAR), clinical status, and neuroimaging. Multifocal ERGs from the central 40° were compared to corresponding fundus imaging. Visual acuity was measured by Teller cards at follow-up. ERGs were compared to controls recorded under anesthesia. RESULTS Sixteen children met inclusion criteria (14 recorded during the acute phase and 2 during long-term follow-up). During the acute phase, ERGs (n = 4 full field; n = 10 multifocal ERG) showed abnormal amplitude, latency, or both in at least one eye. Ten subjects had significantly reduced responses in both eyes, 3 of which had an ERG dominated by a negative waveform (absent b-wave or P1). The remaining six subjects had responses in one eye that were near normal (≥ 50% of controls). ERGs were sometimes abnormal in local areas without hemorrhage. ERGs could be preserved in local areas adjacent to traumatic retinoschisis. Two subjects with reduced visual acuity had belated ERGs: One had an abnormal macular ERG and the other had a normal macular ERG implying cortical visual impairment. At follow-up, 10 of 14 subjects had significant visual acuity loss (≥ 0.7 age-corrected logMAR); four subjects had mild vision loss (≤ 0.5 age-corrected logMAR). Visual acuity outcome was not reliably associated with the fundus appearance in the acute phase. All subjects with a negative ERG waveform had severe vision loss on follow-up. CONCLUSIONS Retinal dysfunction was common during the acute phase of NAT. A near normal appearing fundus did not imply normal retinal function, and ERG abnormality did not always predict a poor visual acuity outcome. However, a negative ERG waveform was associated severe visual acuity loss. Potential artifacts of retinal hemorrhages and anesthesia could not fully account for multifocal ERG abnormalities. Retinal function can be preserved in areas adjacent to traumatic retinoschisis.
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Affiliation(s)
- John P Kelly
- Roger H. Johnson Vision Clinic, Seattle Children's Hospital, Division of Ophthalmology, OA.5.342, Seattle, WA, 98105, USA.
- Department of Ophthalmology, University of Washington, Seattle, USA.
| | - Kenneth Feldman
- Seattle Children's Hospital, Children's Protection Program, Seattle, USA
- Division of General Pediatrics, University of Washington, Seattle, USA
| | - Jason Wright
- Division of Radiology, Seattle Children's Hospital, Seattle, USA
| | - Sheila Ganti
- Center for Clinical and Translational Research, Seattle Children's Hospital, Seattle, USA
| | - James B Metz
- Department of Pediatrics, University of Vermont, Burlington, USA
| | - Avery Weiss
- Department of Ophthalmology, University of Washington, Seattle, USA
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Thresholds for the assessment of inflicted head injury by shaking trauma in infants: a systematic review. Forensic Sci Int 2019; 306:110060. [PMID: 31785511 DOI: 10.1016/j.forsciint.2019.110060] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 11/11/2019] [Accepted: 11/13/2019] [Indexed: 12/14/2022]
Abstract
In order to investigate potential causal relations between the shaking of infants and injuries, biomechanical studies compare brain and skull dynamic behavior during shaking to injury thresholds. However, performing shaking tolerance research on infants, either in vivo or ex vivo, is extremely difficult, if not impossible. Therefore, infant injury thresholds are usually estimated by scaling or extrapolating adult or animal data obtained from crash tests or whiplash experiments. However, it is doubtful whether such data accurately matches the biomechanics of shaking in an infant. Hence some thresholds may be inappropriate to be used for the assessment of inflicted head injury by shaking trauma in infants. A systematic literature review was conducted to 1) provide an overview of existing thresholds for head- and neck injuries related to violent shaking, and 2) to identify and discuss which thresholds have been used or could be used for the assessment of inflicted head injury by shaking trauma in infants. Key findings: The majority of studies establishing or proposing injury thresholds were found to be based on loading cycle durations and loading cycle repetitions that did not resemble those occurring during shaking, or had experimental conditions that were insufficiently documented in order to evaluate the applicability of such thresholds. Injury thresholds that were applied in studies aimed at assessing whether an injury could occur under certain shaking conditions were all based on experiments that did not properly replicate the loading characteristics of shaking. Somewhat validated threshold scaling methods only exist for scaling concussive injury thresholds from adult primate to adult human. Scaling methods that have been used for scaling other injuries, or for scaling adult injury thresholds to infants were not validated. There is a clear and urgent need for new injury thresholds established by accurately replicating the loading characteristics of shaking.
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van Zandwijk JP, Vester MEM, Bilo RA, van Rijn RR, Loeve AJ. Modeling of inflicted head injury by shaking trauma in children: what can we learn? : Part II: A systematic review of mathematical and physical models. Forensic Sci Med Pathol 2019; 15:423-436. [PMID: 30784025 PMCID: PMC6687692 DOI: 10.1007/s12024-019-00093-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2019] [Indexed: 12/01/2022]
Abstract
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.
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Affiliation(s)
- Jan Peter van Zandwijk
- Division of Digital and Biometric Traces, Netherlands Forensic Institute, Laan van Ypenburg 6, 2497, GB, The Hague, the Netherlands
| | - Marloes E M Vester
- Department of Radiology and Nuclear Medicine, Academic Medical Center Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, the Netherlands.,Specialist Services and Expertise Division, Netherlands Forensic Institute, Laan van Ypenburg 6, 2497, GB, The Hague, the Netherlands
| | - Rob A Bilo
- Specialist Services and Expertise Division, Netherlands Forensic Institute, Laan van Ypenburg 6, 2497, GB, The Hague, the Netherlands
| | - Rick R van Rijn
- Department of Radiology and Nuclear Medicine, Academic Medical Center Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, the Netherlands.,Specialist Services and Expertise Division, Netherlands Forensic Institute, Laan van Ypenburg 6, 2497, GB, The Hague, the Netherlands
| | - Arjo J Loeve
- Department of BioMechanical Engineering, Faculty of Mechanical, Maritime & Materials Engineering, Delft University of Technology, Mekelweg 2, 2628, CD, Delft, the Netherlands.
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Karimi A, Razaghi R, Sera T, Kudo S. A combination of the finite element analysis and experimental indentation via the cornea. J Mech Behav Biomed Mater 2019; 90:146-154. [DOI: 10.1016/j.jmbbm.2018.10.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/03/2018] [Accepted: 10/09/2018] [Indexed: 01/10/2023]
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Abstract
PURPOSE To demonstrate vitreoretinal traction as a mechanism for perimacular folds in abusive head trauma. METHODS We performed gross and histopathologic examination of eyes of children with suspected abusive head trauma and identified those with typical perimacular folds. Information was collected regarding the incident that led to the child's death and systemic manifestations noted at autopsy. Eyes were prepared in a fashion that allowed for demonstration of the vitreoretinal interface. RESULTS Ten eyes of five patients (2-13 months) were examined. All patients had systemic manifestations of abusive trauma including intracranial injury. All cases provided evidence of vitreoretinal traction producing perimacular folds. Condensed vitreous was seen attached to the apices of the retinal folds, and the detached internal limiting membrane comprising the inner surfaces of the schisis cavity. Four cases showed severe bilateral multilayered symmetric retinal hemorrhages extending to the ora serrata. All cases showed optic nerve sheath subdural hemorrhage and subarachnoid hemorrhage. Orbital hemorrhage was unilateral in two cases and bilateral in three cases. Four cases showed orbital fat hemorrhage. One case showed extraocular muscle sheath and cranial nerve sheath hemorrhage. Two cases showed juxtapapillary intrascleral hemorrhage. CONCLUSION Vitreoretinal traction is the likely mechanism of perimacular folds in abusive head trauma.
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23
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Nadarasa J, Deck C, Meyer F, Bourdet N, Raul JS, Willinger R. Development of a finite-element eye model to investigate retinal hemorrhages in shaken baby syndrome. Biomech Model Mechanobiol 2017; 17:517-530. [PMID: 29209848 DOI: 10.1007/s10237-017-0975-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 10/28/2017] [Indexed: 10/18/2022]
Abstract
Retinal hemorrhages (RH) are among injuries sustained by a large number of shaken baby syndrome victims, but also by a small proportion of road accident victims. In order to have a better understanding of the underlying of RH mechanisms, we aimed to develop a complete human eye and orbit finite element model. Five occipital head impacts, at different heights and on different surfaces, and three shaking experiments were conducted with a 6-week-old dummy (Q0 dummy). This allowed obtaining a precise description of the motion in those two specific situations, which was then used as input for the eye model simulation. Results showed that four parameters (pressure, Von Mises stress and strain, 1st principal stress) are relevant for shaking-fall comparison. Indeed, in the retina, the softest shaking leads to pressure that is 4 times higher than the most severe impact (1.43 vs. 0.34 kPa). For the Von Mises stress, strain and 1st principal stress, this ratio rises to 4.27, 6.53 and 14.74, respectively. Moreover, regions of high stress and strain in the retina and the choroid were identified and compared to what is seen on fundoscopy. The comparison between linear and rotational acceleration in fall and shaking events demonstrated the important role of the rotational acceleration in inducing such injuries. Even though the eye model was not validated, the conclusion of this study is that compared to falls, shaking an infant leads to extreme eye loading as demonstrated by the values taken by the four mentioned mechanical parameters in the retina and the choroid.
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Affiliation(s)
- Jeyendran Nadarasa
- University of Strasbourg - Icube, Unistra-CNRS, 2 Rue Boussingault, 67000, Strasbourg, France.,Institute of Legal Medicine, 11 Rue Humann, 67085, Strasbourg Cedex, France
| | - Caroline Deck
- University of Strasbourg - Icube, Unistra-CNRS, 2 Rue Boussingault, 67000, Strasbourg, France
| | - Frank Meyer
- University of Strasbourg - Icube, Unistra-CNRS, 2 Rue Boussingault, 67000, Strasbourg, France
| | - Nicolas Bourdet
- University of Strasbourg - Icube, Unistra-CNRS, 2 Rue Boussingault, 67000, Strasbourg, France
| | - Jean-Sébastien Raul
- University of Strasbourg - Icube, Unistra-CNRS, 2 Rue Boussingault, 67000, Strasbourg, France.,Institute of Legal Medicine, 11 Rue Humann, 67085, Strasbourg Cedex, France
| | - Rémy Willinger
- University of Strasbourg - Icube, Unistra-CNRS, 2 Rue Boussingault, 67000, Strasbourg, France.
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Chen Y. State of the art in post-mortem forensic imaging in China. Forensic Sci Res 2017; 2:75-84. [PMID: 30483623 PMCID: PMC6197115 DOI: 10.1080/20961790.2017.1337501] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 05/30/2017] [Indexed: 10/26/2022] Open
Abstract
The autopsy and histopathologic examination are traditional and classic approaches in forensic pathology. In recent years, with the tremendous progresses of computer technology and medical imaging technology, the developed post-mortem computer tomography, post-mortem magnetic resonance imaging and other new methods provide non-invasive, intuitive, high-precision examining methods and research tools for the forensic pathology. As a result, the reconstruction of the injury as well as the analysis of injury mechanism has been essentially achieved. Such methods have become popular in the research field of forensic science and related work has also been carried out in China. This paper reviews the development and application of abovementioned post-mortem forensic imaging methods in China based on the relevant literature.
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Affiliation(s)
- Yijiu Chen
- Institute of Forensic Science, Ministry of Justice, PRC, Shanghai, China
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25
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Quantifying the injury of the human eye components due to tennis ball impact using a computational fluid–structure interaction model. SPORTS ENGINEERING 2015. [DOI: 10.1007/s12283-015-0192-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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26
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Cui YH, Huang JF, Cheng SY, Wei W, Shang L, Li N, Xiong K. Study on establishment and mechanics application of finite element model of bovine eye. BMC Ophthalmol 2015; 15:101. [PMID: 26268321 PMCID: PMC4535564 DOI: 10.1186/s12886-015-0073-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 07/14/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Glaucoma mainly induced by increased intraocular pressure (IOP), it was believed that the pressure that wall of eyeball withstands were determined by material properties of the tissue and stereoscopic geometry of the eyeball. In order to study the pressure changes in different parts of interior eyeball wall, it is necessary to develop a novel eye ball FEM with more accurate geometry and material properties. Use this model to study the stress changes in different parts of eyeball, especially the lamina cribrosa (LC) under normal physiological and pathological IOP, and provide a mathematical model for biomechanical studies of selected retinal ganglion cells (RGCs) death. METHODS (1) Sclera was cut into 3.8-mm wide, 14.5-mm long strips, and cornea was cut into 9.5-mm-wide and 10-mm-long strips; (2) 858 Mini BionixII biomechanical loading instrument was used to stretch sclera and cornea. The stretching rate for sclera was 0.3 mm/s, 3 mm/s, 30 mm/s, 300 mm/s; and for cornea were 0.3 mm/s and 30 mm/s. The deformation-stress curve was recorded; (3) Naso-temporal and longitudinal distance of LC were measured; (4) Micro-CT was used to accurately scan fresh bovine eyes and obtain the geometrical image and data to establish bovine eye model. 3-D reconstruction was performed using these images and data to work out the geometric shape of bovine eye; (5) IOP levels for eyeball FEM was set and the inner wall of eyeball was used taken as load-bearing part. Simulated eyeball FE modeling was run under the IOP level of 10 mmHg, 30 mmHg, 60 mmHg and 100 mmHg, and the force condition of different parts of eyeball was recorded under different IOP levels. RESULTS (1) We obtained the material parameters more in line with physiological conditions and established a more realistic eyeball model using reversed engineering of parameters optimization method to calculate the complex nonlinear super-elastic and viscoelastic parameters more accurately; (2) We observed the following phenomenon by simulating increased pressure using FEM: as simulative IOP increased, the stress concentration scope on the posterior half of sclera became narrower; in the meantime, the stress-concentration scope on the anterior half of scleral gradually expanded, and the stress on the central part of LC is highest. CONCLUSION As simulative IOP increased, stress-concentration scope on the posterior half of sclera gradually narrowed; in the meantime, the stress-concentration scope on the anterior half of sclera gradually expanded, and the stress on the LC is mainly concentrated in the central part, suggesting that IOP is mainly concentrated in the anterior part of the eyeball as it increases. This might provide a biomechanical evidence to explain why RGCs in peripheral part die earlier than RGCs in central part under HIOP.
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Affiliation(s)
- Yan-Hui Cui
- Department of Anatomy and Neurobiology, Morphological Sciences Building, Central South University, 172 Tongzi Po Road, Changsha, Hunan, 410013, China.
| | - Ju-Fang Huang
- Department of Anatomy and Neurobiology, Morphological Sciences Building, Central South University, 172 Tongzi Po Road, Changsha, Hunan, 410013, China.
| | - Si-Ying Cheng
- Eight-year clinical medicine, 2011 grade, Xiangya Medical School, Central South University, Changsha, Hunan, 410013, China.
| | - Wei Wei
- Laboratoire de Biomécanique Appliquée, MRT24 IFSTTAR-Aix-Marseille Université, Bd. P. Dramard, Faculté de Medecine secteur-Nord, Marseille, 13916, France.
| | - Lei Shang
- Department of Anatomy and Neurobiology, Morphological Sciences Building, Central South University, 172 Tongzi Po Road, Changsha, Hunan, 410013, China.
| | - Na Li
- Radiology Department, Third Xiangya Hospital, Central South University, 138 Tongzi Po Road, Changsha, Hunan, 410013, China.
| | - Kun Xiong
- Department of Anatomy and Neurobiology, Morphological Sciences Building, Central South University, 172 Tongzi Po Road, Changsha, Hunan, 410013, China.
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Colter J, Williams A, Moran P, Coats B. Age-related changes in dynamic moduli of ovine vitreous. J Mech Behav Biomed Mater 2015; 41:315-24. [DOI: 10.1016/j.jmbbm.2014.09.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 08/30/2014] [Accepted: 09/02/2014] [Indexed: 11/30/2022]
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Argento A, Kim W, Rozsa FW, DeBolt KL, Zikanova S, Richards JR. Shear behavior of bovine scleral tissue. J Biomech Eng 2014; 136:1870708. [PMID: 24805965 DOI: 10.1115/1.4027615] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Accepted: 05/08/2014] [Indexed: 11/08/2022]
Abstract
Ocular tissue properties have been widely studied in tension and compression for humans and a variety of animals. However, direct shear testing of the tissues of the sclera appear to be absent from the literature even though modeling, analyses, and anatomical studies have indicated that shear may play a role in the etiology of primary open angle glaucoma (POAG). In this work, the mechanical behavior of bovine scleral tissue in shear has been studied in both out-of-plane and in-plane modes of deformation. Stress-strain and relaxation tests were conducted on tissue specimens at controlled temperature and hydration focusing on trends related to specimen location and orientation. There was generally found to be no significant effect of specimen orientation and angular location in the globe on shear stiffness in both modes. The in-plane response, which is the primary load carrying mode, was found to be substantially stiffer than the out-of-plane mode. Also, within the in-plane studies, tissue further from the optic nerve was stiffer than the near tissue. The viscosity coefficient of the tissue varied insignificantly with distance from the optic nerve, but overall was much higher in-plane than out-of-plane.
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Filas BA, Shah NS, Zhang Q, Shui YB, Lake SP, Beebe DC. Quantitative imaging of enzymatic vitreolysis-induced fiber remodeling. Invest Ophthalmol Vis Sci 2014; 55:8626-37. [PMID: 25468895 DOI: 10.1167/iovs.14-15225] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
PURPOSE Collagen fiber remodeling in the vitreous body has been implicated in cases of vitreomacular traction, macular hole, and retinal detachment, and also may occur during pharmacologic vitreolysis. The purpose of this study was to evaluate quantitative polarized light imaging (QPLI) as a tool for studying fiber organization in the vitreous and near the vitreoretinal interface in control and enzymatically perturbed conditions. METHODS Fiber alignment was measured in anterior-posterior sections of bovine and porcine vitreous. Additional tests were performed on bovine lenses and nasal-temporal vitreous sections. Effects of proteoglycan degradation on collagen fiber alignment using trypsin and plasmin were assessed at the microstructural level using electron microscopy and at the global level using QPLI. RESULTS Control vitreous showed fiber organization patterns consistent with the literature across multiple-length scales, including the global anterior-posterior coursing of vitreous fibers, as well as local fibers parallel to the equatorial vitreoretinal interface and transverse to the posterior interface. Proteoglycan digestion with trypsin or plasmin significantly increased fiber alignment throughout the vitreous (P < 0.01). The largest changes (3×) occurred in the posterior vitreous where fibers are aligned transverse to the posterior vitreoretinal interface (P < 0.01). CONCLUSIONS Proteoglycan loss due to enzymatic vitreolysis differentially increases fiber alignment at locations where tractions are most common. We hypothesize that a similar mechanism leads to retinal complications during age-related vitreous degeneration. Structural changes to the entire vitreous body (as opposed to the vitreoretinal interface alone) should be evaluated during preclinical testing of pharmacological vitreolysis candidates.
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Affiliation(s)
- Benjamen A Filas
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Nihar S Shah
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Qianru Zhang
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States Eye Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ying-Bo Shui
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Spencer P Lake
- Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, Missouri, United States
| | - David C Beebe
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, United States
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The eye in child abuse: key points on retinal hemorrhages and abusive head trauma. Pediatr Radiol 2014; 44 Suppl 4:S571-7. [PMID: 25501729 DOI: 10.1007/s00247-014-3107-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 06/18/2014] [Indexed: 10/24/2022]
Abstract
This review presents an up-to-date overview of ocular injuries resulting from child abuse, with a spotlight on abusive head trauma. Retinal hemorrhage is a principle finding of inflicted head trauma. The specific pattern of hemorrhages holds valuable diagnostic information, which can help to guide multidisciplinary assessments of the likelihood of abuse. Indirect ophthalmoscopy through dilated pupils by an ophthalmologist is necessary for adequate examination and documentation of retinal findings. Initial pediatrician evaluation of the eye and indications for ophthalmological consultation are reviewed. Focus is then placed upon understanding retinal hemorrhage patterns, their diagnostic significance and likely pathophysiological mechanisms. The differential diagnosis of retinal hemorrhage in young children is discussed, highlighting key distinctions among retinal hemorrhage patterns, severity and frequencies, as well as other ocular findings. The most common cause of retinal hemorrhage in an infant is trauma, and most other causes can be identified by considering the hemorrhage pattern, ocular or systemic signs and the results of laboratory and imaging tests, when indicated.
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Nadarasa J, Deck C, Meyer F, Willinger R, Raul JS. Update on injury mechanisms in abusive head trauma--shaken baby syndrome. Pediatr Radiol 2014; 44 Suppl 4:S565-70. [PMID: 25501728 DOI: 10.1007/s00247-014-3168-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 06/18/2014] [Accepted: 08/20/2014] [Indexed: 11/30/2022]
Abstract
Violently shaking a baby leads to clinical presentations ranging from seizures to cardiopulmonary arrest. The main injuries sustained are retinal hemorrhages, subdural hemorrhages, and sometimes fractures and spine injury. It is important to have a global view of the injuries sustained by the infant to correctly discuss the biomechanical aspects of abusive head trauma. Recent works based on finite element models have shown that whiplash-shaking alone is enough to generate vitreo-retinal traction leading to retinal hemorrhage and to cause the rupture of bridging veins leading to subdural hemorrhage. We will review the main papers dealing with the mechanisms of shaken baby syndrome and present the most relevant hypothesis concerning the biomechanical aspects of injuries related to shaken baby syndrome.
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Affiliation(s)
- Jeyendran Nadarasa
- University of Strasbourg - Icube, Unistra-CNRS, 2 Rue Boussingault, 67000, Strasbourg, France,
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Liu X, Wang L, Du C, Li D, Fan Y. Mechanism of lens capsular rupture following blunt trauma: a finite element study. Comput Methods Biomech Biomed Engin 2014; 18:914-21. [DOI: 10.1080/10255842.2014.975798] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Yoshida M, Yamazaki J, Mizunuma H. A finite element analysis of the retinal hemorrhages accompanied by shaken baby syndrome/abusive head trauma. J Biomech 2014; 47:3454-8. [DOI: 10.1016/j.jbiomech.2014.09.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 09/05/2014] [Accepted: 09/14/2014] [Indexed: 11/29/2022]
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Yamazaki J, Yoshida M, Mizunuma H. Experimental analyses of the retinal and subretinal haemorrhages accompanied by shaken baby syndrome/abusive head trauma using a dummy doll. Injury 2014; 45:1196-206. [PMID: 24810668 DOI: 10.1016/j.injury.2014.04.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 03/11/2014] [Accepted: 04/05/2014] [Indexed: 02/02/2023]
Abstract
INTRODUCTION We explored several modes of violent shaking using a dummy doll with an eyeball model to reproduce abusive events that lead to retinal haemorrhages (RH) seen in shaken baby syndrome or abusive head trauma (SBS/AHT). MATERIALS AND METHODS A dummy doll equipped with an eyeball model was prepared. The eyeball model was filled with a model of vitreous body, i.e. agar gel or water, and was with a pressure sensor to measure normal stress. RESULTS The modes of shaking were classified into three patterns, i.e. fast shaking with the fore arms, fast shaking with the whole arms and synchronized shaking with the whole arms. The frequency of the cyclic acceleration-deceleration history experienced by the head of the dummy doll was 5.0, 4.0 and 2.2 Hz, respectively, with the maximum acceleration of 20, 20 and 60 m/s(2), respectively. We considered the last of these three modes of shaking as possibly corresponding to the worst case of violent shaking. This mode of shaking could be instructed to volunteers who acted as imitate perpetrators, and resulted in both increased peak intensities of the acceleration experienced by the head of the dummy doll and increased stresses on the retina at the posterior pole of the eyeball model. DISCUSSION The time integral of the stress through a single cycle of shaking was 107 Pa·s, much larger than that of a single event of fall, which resulted in 60-73 Pa·s. Taking into account that abusive shaking is likely to include multiple cycles, the time integral of the stress due to abusive shaking can be even larger. This clear difference may explain why RH in SBS/AHT is frequent, while RH in accidental falls is rare.
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Affiliation(s)
- Junpei Yamazaki
- Department of Mechanical Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan.
| | - Makoto Yoshida
- Department of Mechanical Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan.
| | - Hiroshi Mizunuma
- Department of Mechanical Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan.
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Liu X, Wang L, Wang C, Fan J, Liu S, Fan Y. Prediction of globe rupture caused by primary blast: a finite element analysis. Comput Methods Biomech Biomed Engin 2014; 18:1024-1029. [DOI: 10.1080/10255842.2013.869317] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Gaffar MA, Esernio-Jenssen D, Kodsi SR. Incidence of retinal hemorrhages in abusive head trauma. J Pediatr Ophthalmol Strabismus 2013; 50:169-73. [PMID: 23380029 DOI: 10.3928/01913913-20130129-01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 11/26/2012] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate whether a relationship exists between the presence of retinal hemorrhages and confessions and/or identified perpetrators in cases of abusive head trauma. METHODS A retrospective chart review was conducted of all abusive head trauma cases. All cases that met criteria for abusive head trauma were placed into one of three categories: perpetrator confessed (category A), perpetrator identified without confession (category B), and no perpetrator identified (category C). RESULTS Forty-eight cases met the criteria for abusive head trauma, with 18, 16, and 14 cases in categories A, B, and C, respectively. Retinal hemorrhages were identified in 16 of 18 (88%) cases in category A, 12 of 16 (75%) in category B, and 6 of 14 (43%) in category C. A statistically significant difference regarding the presence of retinal hemorrhages was seen for perpetrator identified (28 of 34 or 82%) compared to no perpetrator identified (6 of 14 or 43%) (P = .034). The difference in retinal hemorrhages was correlated to the higher incidence of acute presentation in the perpetrator identified group (31 of 34 or 91%) compared to that in the perpetrator not identified group (9 of 14 or 64%) (P = .023). CONCLUSION The incidence of retinal hemorrhages in abusive head trauma for identified perpetrators, regardless of a confession, is similar. However, there is a statistically significant decrease in the incidence of retinal hemorrhages in abusive head trauma when comparing identified perpetrators to non-identified perpetrators. This decreased incidence of retinal hemorrhages was statistically correlated to a lower incidence of acute presentation in victims of abusive head trauma without an identified perpetrator.[J Pediatr Ophthalmol Strabismus 2013;50(3):169-172.].
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Affiliation(s)
- Majida A Gaffar
- Department of North Shore-Long Island Jewish Health Systems, Hofstra North Shore-LIJ School of Medicine at Hofstra University, -Long Island Jewish Health Systems, Great Neck, NY 11021, USA.
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Liu X, Wang L, Wang C, Sun G, Liu S, Fan Y. Mechanism of traumatic retinal detachment in blunt impact: A finite element study. J Biomech 2013; 46:1321-7. [DOI: 10.1016/j.jbiomech.2013.02.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 01/31/2013] [Accepted: 02/05/2013] [Indexed: 10/27/2022]
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Kim W, Argento A, Rozsa FW, Mallett K. Constitutive behavior of ocular tissues over a range of strain rates. J Biomech Eng 2013; 134:061002. [PMID: 22757499 DOI: 10.1115/1.4006847] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The constitutive behavior of bovine scleral and corneal tissues is measured in tension and compression, at quasi-static and moderate strain rates. Experiments are conducted at strain rates up to about 50 strain per second by a pneumatic testing system developed to overcome noise and measurement difficulties associated with the time dependent test of low impedance materials. Results for the tissues at room and the natural bovine body temperatures are similar and indicate that ocular tissue exhibits nonlinear stiffening for increasing strain rates, a phenomena termed rate hardening. For example, at a tensile strain rate of 29/s, corneal tissue is found to develop 10 times the stress that it does quasi-statically at the same strain. Thus, conventional constitutive models will grossly underpredict stresses occurring in the corneo-scleral shell due to moderate dynamic events. This has implication to the accuracy of ocular injury models, the study of the stress field in the corneo-scleral shell for glaucoma research and tonometry measurements. The measured data at various strain rates is represented using the general framework of a constitutive model that has been used to represent biological tissue mechanical data. Here it is extended to represent the measured data of the ocular tissues over the range of tested strain rates. Its form allows for straightforward incorporation in various numerical codes. The experimental and analytical methods developed here are felt to be applicable to the test of human ocular tissue.
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Affiliation(s)
- Wonsuk Kim
- Department of Mechanical Engineering, University of Michigan-Dearborn, Dearborn, MI 48128, USA
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Abstract
Retinal hemorrhage is a cardinal manifestation of abusive head trauma. Over the 30 years since the recognition of this association, multiple streams of research, including clinical, postmortem, animal, mechanical, and finite element studies, have created a robust understanding of the clinical features, diagnostic importance, differential diagnosis, and pathophysiology of this finding. The importance of describing the hemorrhages adequately is paramount in ensuring accurate and complete differential diagnosis. Challenges remain in developing models that adequately replicate the forces required to cause retinal hemorrhage in children. Although questions, such as the effect of increased intracranial pressure, hypoxia, and impact, are still raised (particularly in court), clinicians can confidently rely on a large and solid evidence base when assessing the implications of retinal hemorrhage in children with concern of possible child abuse.
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Affiliation(s)
- Alex V Levin
- Pediatric Ophthalmology and Ocular Genetics, Wills Eye Institute, Suite 1210, 840 Walnut St, Philadelphia, PA 19107, USA.
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Abstract
Retinal hemorrhage is an important indicator of possible abusive head trauma, but it is also found in a number of other conditions. Distinguishing the type, number, and pattern of retinal hemorrhages may be helpful in establishing a differential diagnosis. Identification of ocular abnormalities requires a full retinal examination by an ophthalmologist using indirect ophthalmoscopy through a pupil that has been pharmacologically dilated. At autopsy, removal of the eyes and orbital tissues may also reveal abnormalities not discovered before death. In previously well young children who experience unexpected apparent life-threatening events with no obvious cause, children with head trauma that results in significant intracranial hemorrhage and brain injury, victims of abusive head trauma, and children with unexplained death, premortem clinical eye examination and postmortem examination of the eyes and orbits may be helpful in detecting abnormalities that can help establish the underlying etiology.
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Vincent AL, Kelly P. Retinal haemorrhages in inflicted traumatic brain injury: the ophthalmologist in court. Clin Exp Ophthalmol 2010; 38:521-32. [DOI: 10.1111/j.1442-9071.2010.02324.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Forbes BJ, Rubin SE, Margolin E, Levin AV. Evaluation and management of retinal hemorrhages in infants with and without abusive head trauma. J AAPOS 2010; 14:267-73. [PMID: 20603062 DOI: 10.1016/j.jaapos.2010.03.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Revised: 03/30/2010] [Accepted: 03/31/2010] [Indexed: 11/18/2022]
Abstract
Extensive intraocular hemorrhage in young infants in the setting of acute brain injury and in the absence of a history of severe accidental trauma or underlying medical cause must be considered to be nonaccidental injury until otherwise proven. In the absence of any obvious explanation, the presence of any retinal hemorrhage should raise the possibility of abusive head trauma in the differential diagnosis and perhaps lead to such testing as skeletal radiography and neuroimaging, consultation with a child abuse specialist, as well as workup for other relevant systemic conditions. Physicians who treat infants and children are mandated to report suspected child abuse to child welfare agencies for investigation, and ophthalmologists who encounter children with ophthalmic manifestations of abuse need to ensure that the proper steps are taken to protect their patients from the potential for further harm. Ascertainment of abusive head trauma is critical to prevent a potentially fatal recurrence.
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Affiliation(s)
- Brian J Forbes
- Department of Ophthalmology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.
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Wygnanski-Jaffe T, Morad Y, Levin AV. Pathology of retinal hemorrhage in abusive head trauma. Forensic Sci Med Pathol 2009; 5:291-7. [PMID: 20024631 DOI: 10.1007/s12024-009-9134-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/27/2009] [Indexed: 12/01/2022]
Abstract
Abusive head injury, characterized by repeated acceleration-deceleration forces, is associated with retinal hemorrhages as demonstrated in many clinical and postmortem studies. The theory that vitreoretinal traction is the major factor in the pathogenesis of retinal hemorrhages is presently the most widely accepted explanation based on different lines of research. Postmortem examination of the eye and orbital structures is essential for recognizing abusive head injury and also for identifying other possible medical conditions which can cause retinal hemorrhage.
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Vitreoretinal traction is a major factor in causing the haemorrhagic retinopathy of abusive head injury?--yes. Eye (Lond) 2009; 23:1758-60. [PMID: 19662083 DOI: 10.1038/eye.2009.199] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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