Controversy exists regarding whether violent shaking is harmful to infants in the absence of impact. In this study, our objective was to characterize the biomechanical response of the infant head ...during shaking through use of an instrumented anthropomorphic test device (commonly referred to as a "crash test dummy" or surrogate) representing a human infant and having improved biofidelity. A series of tests were conducted to simulate violent shaking of an infant surrogate. The Aprica 2.5 infant surrogate represented a 5th percentile Japanese newborn. A 50th percentile Japanese adult male was recruited to shake the infant surrogate in the sagittal plane. Triaxial linear accelerometers positioned at the center of mass and apex of the head recorded accelerations during shaking. Five shaking test series, each 3-4 sec in duration, were conducted. Outcome measures derived from accelerometer recordings were examined for trends. Head/neck kinematics were characterized during shaking events; mean peak neck flexion was 1.98 radians (113 degrees) and mean peak neck extension was 2.16 radians (123 degrees). The maximum angular acceleration across all test series was 13,260 radians/sec
(during chin-to-chest contact). Peak angular velocity was 105.7 radians/sec (during chin-to-chest contact). Acceleration pulse durations ranged from 72.1 to 168.2 ms. Using an infant surrogate with improved biofidelity, we found higher angular acceleration and higher angular velocity than previously reported during infant surrogate shaking experiments. Findings highlight the importance of surrogate biofidelity when investigating shaking.
Clinicians often miss making the diagnosis of abusive head injury in infants and toddlers who present with mild, non-specific symptoms such as vomiting, fussiness, irritability, trouble sleeping and ...eating, and seizure. If abusive head injury is missed, the child is likely to go on to experience more severe injury. An extensive review of the medical literature was done to summarize what is known about missed abusive head injury and about how these injuries can be recognized and appropriately evaluated. The following issues will be addressed: the definition of mild head injury, problems encountered when clinicians evaluated mildly ill young children with non-specific symptoms, the risk of missing the diagnosis of mild abusive head trauma, the risks involved in subjecting infants and young children to radiation and/or sedation required for neuroimaging studies, imaging options for suspected neurotrauma in children, clinical prediction rules for evaluating mild head injury in children, laboratory tests than can be helpful in diagnosing mild abusive head injury, history and physical examination when diagnosing or ruling out mild abusive head injury, social and family factors that could be associated with abusive injuries, and interventions that could improve our recognition of mild abusive head injuries. Relevant literature is described and evaluated. The conclusion is that abusive head trauma remains a difficult diagnosis to identify in mildly symptomatic young children.
Aim
To investigate the maturation of the peripheral nervous system by analyzing the cross‐sectional area of the sciatic nerve during the first 2 years of life.
Methods
The sciatic nerve was examined ...by high‐resolution ultrasound imaging in 52 children aged 0 days to 10 years, 45 of whom were younger than 2 years. The correlation between the cross‐sectional area of the nerve and the age was statistically tested. A logarithmic regression analysis was performed to develop a logarithmic growth model of the cross‐sectional area.
Results
There is a highly significant correlation between the age and the cross‐sectional area of the sciatic nerve. The growth rate can well be described by a logarithmic model.
Interpretation
Based on the literature on the maturation of the median nerve and nerve roots and the findings of the present study, we conclude that both the proximal and the distal parts of the nerves of the peripheral nervous system increase simultaneously.
What this paper adds
Normative values for the size of the sciatic nerve in children.
The sciatic nerve was examined by high‐resolution ultrasound imaging in children younger than two years. There is a highly significant correlation between the age and the cross‐sectional area of the sciatic nerve. The growth rate can well be described by a logarithmic model.
Aim
To analyze the increase in diameter of the nerve roots C5 and C6 in early childhood.
Methods
The nerve roots of 56 children aged 0 days to 10 years (47 younger than 2 years) were examined by ...high‐resolution ultrasound imaging. The correlation of diameter and age was statistically tested and a logarithmic regression analysis was performed to develop a logarithmic growth model.
Results
The increase in nerve root diameter is greatest during the first 2 years of life and then the growth rate decreases steadily. The relationship between age and diameter follows a logarithmic curve (p < 10–8).
Interpretation
The main increase in the diameter of the nerve roots happens in the first 2 years of life. Comparing data from a previous study, our data also suggest that the maturation of the proximal part of the median nerve is comparable to the maturation of its distal segments. This suggests a synchronous maturation of the axons and myelin sheath for the whole extent of the nerve, from the radix to its very distal part.
What This Paper Adds
Normative values for the size of the cervical nerve roots C5 and C6; an insight into the maturation of the proximal parts of the peripheral nervous system; and the correlation between age and cervical root diameter.
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Mixed-density convexity subdural hematoma and interhemispheric subdural hematoma suggest nonaccidental head injury. The purpose of this retrospective observational study is to investigate subdural ...hematoma on noncontrast computed tomography in infants with nonaccidental head injury and to compare these findings in infants with accidental head trauma for whom the date of injury was known.
Two blinded, independent observers retrospectively reviewed computed tomography scans with subdural hematoma performed on the day of presentation on 9 infant victims of nonaccidental head injury (mean age: 6.8 months; range: 1-25 months) and on 38 infants (mean age: 4.8 months; range: newborn to 34 months) with accidental head trauma (birth-related: 19; short fall: 17; motor vehicle accident: 2).
Homogeneous hyperdense subdural hematoma was significantly more common in children with accidental head trauma (28 of 38 74%; nonaccidental head trauma: 3 of 9 33%), whereas mixed-density subdural hematoma was significantly more common in cases of nonaccidental head injury (6 of 9 67%; accidental head trauma: 7 of 38 18%). Twenty-two (79%) subdural hematomas were homogeneously hyperdense on noncontrast computed tomography performed within two days of accidental head trauma, one (4%) was homogeneous and isodense compared to brain tissue, one (4%) was homogeneous and hypodense, and four (14%) were mixed-density. There was no statistically significant difference in the proportion of interhemispheric subdural hematoma, epidural hematoma, calvarial fracture, brain contusion, or subarachnoid hemorrhage.
Homogeneous hyperdense subdural hematoma is more frequent in cases of accidental head trauma; mixed-density subdural hematoma is more frequent in cases of nonaccidental head injury but may be observed within 48 hours of accidental head trauma. Interhemispheric subdural hematoma is not specific for inflicted head injury.
When cases of suspected abusive head trauma are adjudicated in courts of law, several alternative theories of causation are frequently presented. This paper reviews common theories and examines their ...scientific basis.
Purpose To develop a finite element analysis of the eye and orbit that can be subjected to virtual shaking forces. Methods LS-DYNA computer software was used to design a finite element model of the ...human infant eye, including orbit, fat, sclera, retina, vitreous, and muscles. The orbit was modeled as a rigid solid; the sclera and retina as elastic shells; the vitreous as viscoelastic solid or Newtonian fluid; and fat as elastic or viscoelastic solid. Muscles were modeled as spring-damper systems. Orbit-fat, fat-sclera, sclera-retina, and vitreous nodes-retina interfaces were defined with the use of the tied surface-surface function in LS-DYNA. The model was subjected to angular acceleration pulses obtained from shaking tests of a biofidelic doll (Aprica 2.5 kg dummy). Parametric studies were conducted to evaluate the effect of varying the material properties of vitreous/fat on maximum stress and stress distribution. Results With the vitreous modeled as a Newtonian fluid, the repeated acceleration-deceleration oscillatory motion characteristic of abusive head trauma (AHT) causes cumulative increases in the forces experienced at the vitreoretinal interface. Under these vitreous conditions, retinal stress maximums occur at the posterior pole and peripheral retina, where AHT retinal hemorrhage is most often found. Conclusions Our model offers an improvement on dummy and animal models in allowing analysis of the effect of shaking on ocular tissues. It can be used under certain material conditions to demonstrate progressive “stacking” of intraocular stresses in locations corresponding to typical AHT injury patterns, allowing a better understanding of the mechanisms of retinal hemorrhage patterns.
Medicine discovers child abuse Jenny, Carole
JAMA : the journal of the American Medical Association,
2008-Dec-17, Letnik:
300, Številka:
23
Journal Article
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