Physiological and histopathological responses following closed rotational head injury depend on direction of head motion

• Published in: Experimental neurology Vol. 227; no. 1; pp. 79 - 88
• Main Authors: Eucker, Stephanie A., Smith, Colin, Ralston, Jill, Friess, Stuart H., Margulies, Susan S.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.01.2011; Elsevier
• Subjects: Analysis of Variance; Animal models; Animals; Animals, Newborn; Biological and medical sciences; Brain - pathology; Brain ischemia; Brain trauma; Cerebral blood flow; Cerebrovascular Circulation - physiology; Diffuse Axonal Injury - etiology; Disease Models, Animal; Head Injuries, Closed - pathology; Head Injuries, Closed - physiopathology; Head Movements - physiology; Hypoxia-Ischemia, Brain - etiology; Hypoxia-Ischemia, Brain - pathology; Injuries of the nervous system and the skull. Diseases due to physical agents; Medical sciences; Motion; Neurology; Neuropathology; Rotation - adverse effects; Severity of Illness Index; Subarachnoid hemorrhage; Subarachnoid Hemorrhage - etiology; Subarachnoid Hemorrhage - veterinary; Swine; Traumas. Diseases due to physical agents; CPP; Animal models; Neuropathology; Subarachnoid hemorrhage; CBF; FM; Brain trauma; Cerebral blood flow; SaO2; ICP; Brain ischemia; TBI; SAH; MAP; Animal model; Motion; Nervous system diseases; Head; Craniocerebral; Central nervous system; Cardiovascular disease; Cerebral disorder; Blood flow; Encephalon; Vascular disease; Histopathology; Central nervous system disease; Hemodynamics; Head trauma; Cerebrovascular disease
• ISSN: 0014-4886; 1090-2430
• DOI: 10.1016/j.expneurol.2010.09.015

Rotational inertial forces are thought to be the underlying mechanism for most severe brain injuries. However, little is known about the effect of head rotation direction on injury outcomes, particularly in the pediatric population. Neonatal piglets were subjected to a single non-impact head rotation in the horizontal, coronal, or sagittal direction, and physiological and histopathological responses were observed. Sagittal rotation produced the longest duration of unconsciousness, highest incidence of apnea, and largest intracranial pressure increase, while coronal rotation produced little change, and horizontal rotation produced intermediate and variable derangements. Significant cerebral blood flow reductions were observed following sagittal but not coronal or horizontal injury compared to sham. Subarachnoid hemorrhage, ischemia, and brainstem pathology were observed in the sagittal and horizontal groups but not in a single coronal animal. Significant axonal injury occurred following both horizontal and sagittal rotations. For both groups, the distribution of injury was greater in the frontal and parietotemporal lobes than in the occipital lobes, frequently occurred in the absence of ischemia, and did not correlate with regional cerebral blood flow reductions. We postulate that these direction-dependent differences in injury outcomes are due to differences in tissue mechanical loading produced during head rotation. ►Sagittal rotational injury produced more severe outcomes than horizontal or coronal. ► Significant axonal injury occurred after horizontal and sagittal rotations. ► Significant cerebral blood flow reductions occurred after sagittal rotations. ► Traumatic axonal injury frequently occurred in the absence of ischemic injury. ► Axonal injury did not correlate with post-injury cerebral blood flow reductions