The importance of brain temperature in patients after severe head injury: relationship to intracranial pressure, cerebral perfusion pressure, cerebral blood flow, and outcome.

Brain temperature was continuously measured in 58 patients after severe head injury and compared to rectal temperature, intracranial pressure, cerebral blood flow, and outcome after 3 months. The temperature difference between brain and rectal temperature was also calculated. Mild hypothermia (34-36 degrees C) was also used to treat uncontrollable intracranial pressure (ICP) above 20 mm Hg when other methods failed. Brain and rectal temperature were strongly correlated (r = 0.866; p < 0.001). Four groups were identified. The mean brain temperature ranged from 36.9 +/- 0.4 degrees C in the normothermic group to 38.2 +/- 0.5 degrees C in the hyperthermic group, 35.3 +/- 0.5 degrees C in the mild therapeutic hypothermia group, and 34.3 +/- 1.5 degrees C in the hypothermia group without active cooling. The mean DeltaT(br-rect) was positive for patients with a T(br) above 36.0 degrees C (0.0 +/- 0.5 degrees C) and negative for patients during mild therapeutic hypothermia (-0.2 +/- 0.6 degrees C) and also in those with a brain temperature below 36 degrees C without active cooling (0.8 +/- -1.4 degrees C) - the spontaneous hypothermic group. The cerebral perfusion pressure (CPP) was increased significantly by active cooling compared to the normothermic and hyperthermic groups. The mean cerebral blood flow (CBF) in patients with a brain temperature between 36.0 degrees C and 37.5 degrees C was 37.8 +/- 14.0 mL/100 g/min. The lowest CBF was measured in patients with a brain temperature <36.0 degrees C and a negative brain-rectal temperature difference (17.1 +/- 14.0 mL/100 g/min). A positive trend for improved outcome was seen in patients with mild hypothermia. Simultaneous monitoring of brain and rectal temperature provides important diagnostic and prognostic information to guide the treatment of patients after severe head injury (SHI) and the wide differentials that can develop between the brain and core temperature, especially during rapid cooling, strongly supports the use of brain temperature measurement if therapeutic hypothermia is considered for head injury care.

Diagnosis of Erdheim-Chester disease by using computerized tomography-guided stereotactic biopsy of a caudate lesion. Case report.

The authors present the case of a 27-year-old woman with Erdheim-Chester disease (ECD) and extensive intracranial involvement, in whom the initial diagnosis of ECD was established based on computerized tomography (CT)-guided stereotactic biopsy of a caudate lesion. Erdheim-Chester disease is a rare non-Langerhans cell histiocytosis of unknown origin that is clinically characterized by bone pain, diabetes insipidus, and exophthalmos. The radiological hallmarks of the disease include symmetrical sclerosis of the long bones with epiphysial sparing and increased tracer uptake in lesions seen on scintigraphic imaging. Erdheim-Chester disease is characterized histologically by the presence of infiltrating lipid-laden histiocytes that commonly involve the retroperitoneum, orbits, skin, pericardium, lungs, and long bones. Although the occurrence of diabetes insipidus often precedes the diagnosis of ECD by more than a decade in most patients, magnetic resonance imaging- and CT-documented central nervous system involvement is exceedingly rare. In the setting of neurological involvement, neurosurgical biopsy has been reported seven times in the literature, with only one of these biopsies being the basis for the initial diagnosis of the disease. The authors' case represents only the second time the disease has been diagnosed by means of neurosurgical biopsy, highlighting the diagnostic difficulties that patients with EDC present. Skeletal radiographs were confirmatory in this case and this modality should be emphasized as the simplest and most direct route to the diagnosis. The degree of neurological involvement further distinguishes the case presented from prior reports in the literature. The multiple bilateral intraaxial lesions were intensely enhancing on contrast CT scans, distributed infra- and supratentorially, involving both white and gray matter, and associated with diffuse cerebral edema. The case presented is also remarkable by virtue of the symmetrical involvement of the caudate nuclei, representing the first such example documented in the literature. The diagnosis, treatment, and outcome in this patient are discussed, and a review of the literature is presented.

Relationship between brain temperature, brain chemistry and oxygen delivery after severe human head injury: the effect of mild hypothermia.

We studied brain temperature and the effect of mild hypothermia in 58 patients after severe head injury (SHI). Brain tissue oxygen tension (ptiO2), carbon dioxide tension (ptiCO2), tissuie pH (pHti) and temperature (T.br) were measured using a multiparameter probe. Microdialysis was performed to measure glucose, lactate, glutamate, and aspartate in the extracellular fluid. Mild hypothermia (34 degrees-36 degrees C) was employed in 33 selected patients who had persistent increased intracranial pressure (ICP > 20 mmHg). Mild induced hypothermia decreased brain oxygen significantly from 33 +/- 24 mmHg to 30 +/- 22 mmHg (p < 0.05). The ptiCO2 (46 +/- 8 mmHg) was also significantly lower during mild hypothermia (40.4 +/- 4.0 mmHg), p < 0.0001). The pHti increased from 7.13 +/- 0.15 to 7.24 +/- 0.10 (p < 0.0001) under hypothermic conditions. Induced hypothermia may protect patients from secondary ischemic events by lowering the critical ptiO2 threshold, reducing anaerobic metabolism, and decreasing the release of excitatory aminoacids. However, patients with spontaneous brain hypothermia on admission (Tbr < 36.0 degrees C) showed significantly higher levels of glutamate as well as lactate, compared to all other patients, and had a worse outcome. Spontaneous brain hypothermia carries a poor prognosis, and was characterized by markedly abnormal brain metabolic indices.

Clinical trials in traumatic brain injury: lessons for the future.

Thus far, none of the neuroprotective drugs that have been tested to reduce or prevent secondary ischemic brain damage have been shown clear benefit. We will attempt to identify factors that may be responsible for some of these failures. We also will give our thoughts on how to prevent these pitfalls in the usefulness and criteria for use of animal models for traumatic brain injury to depict human head injury are discussed. Clearly, mechanism-driven trials, in which individual pathophysiological mechanisms are targeted, are more likely to show benefit in this heterogeneous patient population. Other factors, such as the effect of brain penetration, safety and tolerability of the compound, and the interface between the pharmaceutical industry and academics are a major influence in the success of these trials. Furthermore, the way trials have been analyzes in the past may not always have been be the most appropriate to show benefits. It is clear that a multi-targeted approach is necessary to address the complicated and closely related mechanisms seen after traumatic and or ischemic brain damage.

A model for neurosurgical humanitarian aid based on 12 years of medical trips to South and Central America.

The pediatric neurosurgical mission trips led by physicians at Virginia Commonwealth University (VCU) Health Systems began in 1996 with the formation of Medical Outreach to Children, founded by 1 of the authors (J.D.W.) after a visit to Guatemala. Since then, 19 surgical trips to 4 different countries in Central and South America have been coordinated from 1996 to 2008. This humanitarian work serves a number of purposes. First and foremost, it provides children with access to surgical care that they would otherwise not receive, thereby significantly improving their quality of life. Second, the visiting surgical team participates in the education of local physicians, parents, and caregivers to help improve the healthcare provided to the children. Last, the team works to promote sustainable global health solutions in the countries it travels to by generating a forum for clinical and public health research discourse. Thus far, a total of 414 children have undergone 463 operations, including 154 initial shunt surgeries, 110 myelomeningocele repairs, 39 lipoma resections, 33 tethered cord releases, 18 shunt revisions, 16 encephalocele repairs, 9 lipomyelomeningocele repairs, and 7 diastematomyelia repairs. The complication rate has been 5-8%, and the team has obtained reliable follow-up in approximately 77% of patients. A correlation was found between an increase in the number of trained neurosurgeons in the host countries and a decrease in the average age of patients treated by the visiting surgical team over time. It is also hypothesized that a decrease in the percentage of myelomeningocele repairs performed by the surgical team (as a fraction of total cases between 1996 and 2006) correlates to an increase in the number of local neurosurgeons able to treat common neural tube defects in patients of younger ages. Such analysis can be used by visiting surgical teams to assess the changing healthcare needs in a particular host country.