Chapter 1 Introductionm

Traumatic brain injury (TBI) affects up to 2% of the population per year, and constitutes the major cause of death and severe disability among young people. By far, the most important complication of TBI is the development of an intracranial hematoma, which complicates 25 to 45% of severe TBI cases, 3 to 12% of moderate TBI cases, and approximately 1 in 500 patients with mild TBI (20). Without effective surgical management, an intracranial hematoma may transform an otherwise benign clinical course with the expectation of recovery to a situation in which death or permanent vegetative survival will occur. Moreover, prolonged delay in the diagnosis or evacuation of an intracranial hematoma may produce a similar result. As many as 100,000 patients per year may require surgical management for a posttraumatic intracranial hematoma in the United States alone. For these reasons, the impact that neurosurgeons can have on the care of such patients is enormous, and perhaps, more than in any other area of emergency medicine, the aggressiveness and rapidity with which care is provided for an intracranial hematoma will determine the outcome (8). Picard et al. (13) have shown that craniotomy for evacuation of an acute epidural hematoma is one of the most cost-effective of all surgical procedures. For this particular subgroup, which may represent up to 5% of patients with severe and moderate TBI, the quality of outcome has been shown to vary dramatically among different hospitals with different levels of commitment to acute neurotrauma care (2, 6, 11). It is for this reason, more than any other, that neurosurgical consultation in the Emergency Room should be promptly available and is a mandated requirement for Level I certification of Trauma centers (1). Although there is evidence that posttraumatic intracranial mass lesions have been removed surgically up to 4000 years ago by the Egyptians andMeso-Americans, it was not until a series of publications emerged in the late 1960s that it became generally accepted that excellent results could be achieved with craniotomy for removal of extradural hematomas (9). For acute subdural hematomas and intraparenchymal lesions, such as contusions and traumatic intracerebral hematomas, the outcome has historically been much worse, because up to 60% of patients with acute subdural hematomaswill die or remain severely disabled (10). During the early 1970s, a series of publications from the Medical College of Virginia demonstrated that wide decompressive craniotomy with duraplasty was one of the most effective forms of therapy for raised intracranial pressure in patients with mass lesions (4). Subsequently, most neurosurgical centers with an interest in TBI have also applied the same craniotomy technique to patients with intraparenchymal contusions, with improvements in outcome. However, there is also widespread dissent and controversy regarding the surgical management of intraparenchymal lesions, with some neurosurgeons maintaining that aggressive surgical intervention, although able to preserve life, will result in a very poor quality of life for survivors (7, 15). With our increasing understanding of the pathomechanisms in severe and moderate TBI have come changes in our approach to management of patients with posttraumatic intracranial mass lesions. For example, it is now well accepted that most intraparenchymal mass lesions (contusions and intracerebral hematomas) will enlarge with time, necessitating serial computed tomographic scanning, and usually intracranial pressure monitoring during the first few days (12, 17). Similarly, the propensity of patients with posttraumatic coagulation disorders to develop intraparenchymal bleeding that is more severe is now well accepted, and has led to management of coagulation disorders in the head injured population that is much more aggressive (18). In turn, these practices led to an increase in the performance of craniotomy, both for evacuation of intraparenchymal mass lesions and as a decompressive measure. Recently, several publications have shown that, within the context of modern aggressive neuro-intensive