Neurosurg Focus
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Review Case Reports
Is there an upper limit of intracranial pressure in patients with severe head injury if cerebral perfusion pressure is maintained?
Authors of recent studies have championed the importance of maintaining cerebral perfusion pressure (CPP) to prevent secondary brain injury following traumatic head injury. Data from these studies have provided little information regarding outcome following severe head injury in patients with an intracranial pressure (ICP) greater than 40 mm Hg, however, in July 1997 the authors instituted a protocol for the management of severe head injury in patients with a Glasgow Coma Scale score lower than 9. The protocol was focused on resuscitation from acidosis, maintenance of a CPP greater than 60 mm Hg through whatever means necessary as well as elevation of the head of the bed, mannitol infusion, and ventriculostomy with cerebrospinal fluid drainage for control of ICP. ⋯ Data from this preliminary study indicate that intense, aggressive management of CPP can lead to good neurological outcomes despite extremely high ICP. Aggressive CPP therapy should be performed and maintained even though apparently lethal ICP levels may be present. Further study is needed to support these encouraging results.
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The atlantoaxial region has been extensively described as a spinal segment especially prone to injury in children. In this clinical review, the authors evaluate and summarize the management of 23 pediatric cases of atlantoaxial instability treated between March 1990 and October 2002. Four broad categories of atlantoaxial problems were observed-atlantoaxial rotatory subluxation in six patients, anterior-posterior atlantoaxial instability caused by ligamentous injury or congenital ligamentous laxity (10 patients), atlantoaxial fracture with or without dislocation (five patients), and atlantooccipital dislocation (two patients). ⋯ Various techniques of surgical stabilization including transarticular screws with sublaminar wiring, transoral decompression with posterior plating, and laminectomy with Steinmann pin occipital-cervical fusion were used with good results. Both patients with atlantooccipital dislocation underwent immediate Locksley occipital-cervical fusion, with marked neurological improvement. Individualized case management must be based on clinical presentation, with internal fixation being the last resort.
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Review
What is the optimal threshold for cerebral perfusion pressure following traumatic brain injury?
Intensive care of the patient with traumatic brain injury centers on control of intracranial pressure and cerebral perfusion pressure (CPP). The optimal CPP by definition delivers an adequate supply of blood and oxygen to meet the metabolic demands of brain tissue. ⋯ No study that accurately assesses the efficacy of normal CPP compared with elevated CPP has been performed, but several studies demonstrate that a CPP threshold exists on an individual basis for patients with TBI. The use of brain monitors of cerebral metabolism and oxygen supply may assist the clinician in the selection of the optimal CPP for an individual patient.
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An intractable increase in intracranial pressure (ICP) leading to a progressive decrease in cerebral perfusion pressure (CPP) and cerebral blood flow (CBF) is the dominating cause of death in patients with severe brain trauma. Arterial hypotension may further compromise CPP (and CBF) and significantly contributes to death. In addition, the injured brain is sensitive to raised CPP due to an increased permeability of the blood-brain barrier (BBB) to crystalloids and an impaired pressure autoregulation of the CBF. ⋯ This level varies among different patients and different areas of the brain. In fact, the penumbral zones surrounding focal brain lesions appear to be the most sensitive. In the individual patient, preservation of normal cerebral energy metabolism within areas at risk during a decrease in CPP can be guaranteed by performing intracerebral microdialysis and bedside biochemical analyses.
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Review Case Reports
Intracranial hypotension syndrome: a comprehensive review.
Intracranial hypotension may have variable clinical presentations, but has a rather uniform component of postural headache among its symptomatology. Its symptoms are explainable given the effects of the hypotension and attempts within the craniospinal axis to maintain volume homeostasis in the face of cerebrospinal fluid leakage (Monro-Kellie hypothesis). The imaging corollaries of the consequences of intracranial hypotension are especially well depicted on magnetic resonance imaging studies.