Head injury mechanisms and the concept of preventive management: a review and critical synthesis.

Recent advances in head injury research have produced a plethora of useful data coupled with a paucity of conceptual integration across the four ways in which this research is pursued. These research orientations are the epidemiological, biomechanical, basic neuroscientific, and clinicopathologic/therapeutic (including rehabilitation). This overview of the history and current state of the art assumes that biomechanics is the basic science of causation in head injury research and when fully integrated with its counterparts, physiology and pathology, it can serve to overcome our conceptual handicaps. A paradigm integrating biomechanics; into the sequence of preventive, protective, acute therapeutic, and rehabilitative interventions will be described as the concept of preventive management. From this we derive the hypothesized claim that the exact biomechanics and the physiopathologic response at the time of injury (at the macroscopic and microscopic levels) determine the sequence of so-called secondary effects that are conceived as the inexorable delayed manifestations of the primary events and concomitant boundary conditions. Knowledge of these events will enable accurate predictions of the natural history and outcome of head injuries from observations carried out in the early acute phase. Examples to test this claim will be given with particular reference to the two types of traumatic brain injury (TBI) phenomenologically associated with disturbances of consciousness, the onset of which can be either immediate or delayed. The current economics and availability of computational power provide a significant opportunity for the development of selected experimental, physical, and simulated models of head injury on the basis of which the complex neurovascular and nonneural cellular and fluid elements of the nervous system may be accurately modeled. This approach will significantly improve the efficiency and quality of the essential biological and clinical observations and model experiments required to validate the theoretical methods and their predictions.