title: Cyclic Head Rotations Produce Modest Brain Injury in Infant Piglets.
abstract: Repetitive back-and-forth head rotation from vigorous shaking is purported to be a central mechanism responsible for diffuse white matter injury, subdural hemorrhage, and retinal hemorrhage in some cases of abusive head trauma (AHT) in young children. Although animal studies have identified mechanisms of traumatic brain injury (TBI) associated with single rapid head acceleration-decelerations at levels experienced in a motor vehicle crash, few experimental studies have investigated TBI from repetitive head rotations. The objective of this study was to systematically investigate the post-injury pathological time-course after cyclic, low-velocity head rotations in the piglet and compare them with single head rotations. Injury metrics were the occurrence and extent of axonal injury (AI), extra-axial hemorrhage (EAH), red cell neuronal/axonal change (RCNAC), and ocular injury (OI). Hyperflexion/extension of the neck were purposefully avoided in the study, resulting in unscaled angular accelerations at the lower end of reported infant surrogate shaking kinematics. All findings were at the mild end of the injury spectrum, with no significant findings at 6 h post-injury. Cyclic head rotations, however, produced modest AI that significantly increased with time post-injury (p < 0.035) and had significantly greater amounts of RCNAC and EAH than noncyclic head rotations after 24 h post-injury (p < 0.05). No OI was observed. Future studies should investigate the contributions of additional physiological and mechanical features associated with AHT (e.g., hyperflexion/extension, increased intracranial pressure from crying or thoracic compression, and more than two cyclic episodes) to enhance our understanding of the causality between proposed mechanistic factors and AHT in infants.
authors.affiliation: 1 Department of Mechanical Engineering, University of Utah , Salt Lake City, Utah.
authors.forename: Brittany
authors.initials: B
authors.lastname: Coats
authors.affiliation: 2 Department of Ophthalmology, Children's Hospital of Philadelphia , Philadelphia, Pennsylvania.|3 Department of Ophthalmology, University of Pennsylvania , Philadelphia, Pennsylvania.
authors.forename: Gil
authors.initials: G
authors.lastname: Binenbaum
authors.affiliation: 4 Department Pathology, Edinburgh University , Edinburgh, Scotland.
authors.forename: Colin
authors.initials: C
authors.lastname: Smith
authors.affiliation: 3 Department of Ophthalmology, University of Pennsylvania , Philadelphia, Pennsylvania.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Peiffer
authors.affiliation: 5 Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania , Philadelphia, Pennsylvania.
authors.forename: Cindy W
authors.initials: CW
authors.lastname: Christian
authors.affiliation: 6 Department of Neurosurgery, Massachusetts General Hospital and Harvard University , Boston, Massachusetts.
authors.forename: Ann-Christine
authors.initials: AC
authors.lastname: Duhaime
authors.affiliation: 7 Department of Bioengineering, University of Pennsylvania , Philadelphia, Pennsylvania.
authors.forename: Susan S
authors.initials: SS
authors.lastname: Margulies
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001696:Biomechanical Phenomena / Q000502:physiology; D001930:Brain Injuries / Q000473:pathology* / Q000503:physiopathology; D006259:Craniocerebral Trauma / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D008297:Male; D012399:Rotation / Q000009:adverse effects*; D038642:Shaken Baby Syndrome / Q000473:pathology / Q000503:physiopathology; D013552:Swine
keywords: abusive head trauma; biomechanics; pediatric traumatic brain injury; shaken baby syndrome