Contribution of edema and cerebral blood volume to traumatic brain swelling in head-injured patients

Post-traumatic hypoxia exacerbates neurological deficit, neuroinflammation and cerebral metabolism in rats with diffuse traumatic brain injury

Background

The combination of diffuse brain injury with a hypoxic insult is associated with poor outcomes in patients with traumatic brain injury. In this study, we investigated the impact of post-traumatic hypoxia in amplifying secondary brain damage using a rat model of diffuse traumatic axonal injury (TAI). Rats were examined for behavioral and sensorimotor deficits, increased brain production of inflammatory cytokines, formation of cerebral edema, changes in brain metabolism and enlargement of the lateral ventricles.

Methods

Adult male Sprague-Dawley rats were subjected to diffuse TAI using the Marmarou impact-acceleration model. Subsequently, rats underwent a 30-minute period of hypoxic (12% O₂/88% N₂) or normoxic (22% O₂/78% N₂) ventilation. Hypoxia-only and sham surgery groups (without TAI) received 30 minutes of hypoxic or normoxic ventilation, respectively. The parameters examined included: 1) behavioural and sensorimotor deficit using the Rotarod, beam walk and adhesive tape removal tests, and voluntary open field exploration behavior; 2) formation of cerebral edema by the wet-dry tissue weight ratio method; 3) enlargement of the lateral ventricles; 4) production of inflammatory cytokines; and 5) real-time brain metabolite changes as assessed by microdialysis technique.

Results

TAI rats showed significant deficits in sensorimotor function, and developed substantial edema and ventricular enlargement when compared to shams. The additional hypoxic insult significantly exacerbated behavioural deficits and the cortical production of the pro-inflammatory cytokines IL-6, IL-1β and TNF but did not further enhance edema. TAI and particularly TAI+Hx rats experienced a substantial metabolic depression with respect to glucose, lactate, and glutamate levels.

Conclusion

Altogether, aggravated behavioural deficits observed in rats with diffuse TAI combined with hypoxia may be induced by enhanced neuroinflammation, and a prolonged period of metabolic dysfunction.

Pediatric high grade glioma of the spinal cord: results of the HIT-GBM database

Little is known about pediatric spinal cord high grade gliomas (SCHGG) beyond their dismal prognosis. Here, we analyzed the HIT-GBM(®) database for the influence of surgical resection on survival. Between 1991 and 2010 the HIT-GBM group collected data from European children diagnosed with high grade glioma. Patients with the following inclusion criteria were analyzed in this study: astrocytic histology, WHO grade III or IV, age at diagnosis <18 years, and tumor localized to the spinal cord. 28 patients (mean age 11.28 years, 14 male) with primary SCHGG were identified. The tumor sizes were measured by the span across adjacent vertebrae and varied greatly (range: 1-20, median: 4). Histology was classified as WHO grade III in 15 and grade IV in 13 tumors. Of note, the four largest tumors identified were WHO grade III. Surgery was classified as complete resection (n = 6), subtotal resection (STR) (n = 7), partial resection (n = 12) or biopsy only (n = 3). 27 patients received chemotherapy, 22 of which also received radiation. With the mean follow-up time of 2.88 (SD ± 2.95) years, 14 patients were still alive resulting in a median overall survival of 2.5 years (SE ± 1.6). The positive prognostic indicators for overall survival were: age younger than 5 years (P = 0.047), WHO grade III (P = 0.046), absence of necrosis (P = 0.025) and gross total resection (GTR) (P = 0.012). The prognosis of SCHGG might not be as miserable as generally assumed. GTR is of benefit. Larger data sets and meta-analysis are necessary to identify patient sub-groups.

Complications associated with the treatment for spinal ependymomas

Spinal cord ependymomas are rare neoplasms, comprising approximately 5% of all CNS tumors and 15% of all spinal cord tumors. Although surgery was once reserved for diagnosis alone, the evolution of surgical practices has elevated resection to the treatment of choice for these lesions. While technological advances continue to improve the capacity for gross-total resections and thus decrease the risk of recurrence, ependymoma spinal surgery still contains a variety of potential complications. The presence of neurological deficits and deterioration are not uncommonly associated with spinal cord ependymoma surgery, including sensory loss, dorsal column dysfunction, dysesthetic syndrome, and bowel and bladder dysfunction, particularly in the immediate postoperative period. Surgical treatment may also lead to wound complications and CSF leaks, with increased risk when radiotherapy has been involved. Radiation therapy may also predispose patients to radiation myelopathy and ultimately result in neurological damage. Additionally, resections of spinal ependymomas have been associated with postoperative spinal instability and deformities, particularly in the pediatric population. Despite the advances in microsurgical techniques and intraoperative cord monitoring modalities, there remain a number of serious complications related to the treatment of spinal ependymoma tumors. Identification and acknowledgment of these potential problems may assist in their prevention, early detection, and increased quality of life for patients afflicted with this disease.

Quantification of brain edema and hemorrhage by MRI after experimental traumatic brain injury in rabbits predicts subsequent functional outcome

We use multiple MRI modalities to measure cerebral edema and intracerebral hemorrhage quantitatively after TBI in rabbits and to acquire the early prognostic MRI information. Multiple MRI modalities (DCE-MRI, DWI and SWI) were used to assess cerebral edema and intracerebral hemorrhage quantitatively at different time points within a month after TBI in 15 rabbits. The functional outcomes were evaluated at 1 and 30 days after TBI. The relationships between the quantitative MRI information at different time points and functional outcome at 30 days were analyzed. The volume transfer coefficient (K (trans)) in the focal lesion area and the perifocal lesion area at the acute phase correlated with the functional outcome at 30 days (p < 0.05). The apparent diffusion coefficient (ADC) value at 7 days in the focal lesion area correlated with the functional outcome at 30 days (p < 0.01) and had a trend to correlate at 3 days (p = 0.08). In the perifocal lesion area, the ADC values at both acute and subacute phase correlated with the functional outcome at 30 days (p < 0.05). The volume of hemorrhage correlated with functional outcome at 30 days (p < 0.05). The cerebral edema assessed by DCE-MRI (K (trans)) and DWI (ADC) and intracerebral hemorrhage assessed by SWI may have predictive values.

Spinal cord tumors in children under the age of 3 years: a retrospective Canadian review

BACKGROUND

Tumors of the spinal cord are exceedingly rare in infancy and only a paucity of literature exists describing the spectrum of this disease and its management. The objectives of our study were to describe the demographic characteristics of spinal cord tumors (SCT) in children less than 3 years of age at diagnosis and to review their treatment and outcome.

METHODS

A national retrospective chart review was conducted on patients under the age of 3 years diagnosed with a primary tumor of the central nervous system (CNS) between 1990 and 2005 across Canada. Inclusion criteria were: age ≤ 3 years, histologic confirmation of the diagnosis, and residency in Canada. A centralized database was created and information regarding SCT was extracted.

RESULTS

Twenty-five of five hundred seventy-nine patients (4.3%) in the data bank had a SCT. The majority of tumors were low-grade astrocytomas (14/25). Leptomeningeal dissemination based on neuroradiologic imaging and/or cerebrospinal fluid cytology was present in five (20%) patients. The majority of patients underwent an incomplete surgical resection (52%). Most patients (64%) did not receive postoperative radiotherapy or chemotherapy. Seventy-two percent (18/25) developed recurrent/progression of disease. Overall 2- and 5-year survival for low- and high-grade malignancies was 93 ± 6.4% and 37.5 ± 17.1% respectively. Significant predictors of survival included mean duration of symptoms prior to initial diagnosis and recurrence/progression of disease.

CONCLUSIONS

Relapse/progression of disease in infant SCT is frequent. Prolonged survival of low-grade tumors is possible with further therapy; however, the prognosis of high-grade malignancies remains poor.

Continuous ventricular cerebrospinal fluid drainage with intracranial pressure monitoring for management of posttraumatic diffuse brain swelling

BACKGROUND: Ventricular drainage has played an important role in the management of traumatic brain-injured patients. The aim of the present study was describe outcomes in a series of 57 patients with diffuse brain swelling underwent to intracranial pressure (ICP) monitoring. METHOD: Fifty-eight patients with diffuse posttraumatic brain swelling, were evaluated prospectively. The Glasgow Coma Scale (GCS) scores of patients varied from 4 to 12. Patients groups divided according to GCS and age. Patient neurological assessment was classified as favorable, unfavorable, and death. RESULTS: Mechanisms of injury were vehicle accidents in 72.4% and falls in 15.6%. 54% of patients had GCS scores between 6 and 8. There were no statistical differences, regarding outcome, between groups separated by age. In the adults group (n=47), 44.7% evolved favorably. CONCLUSION: Our results indicate a poor prognosis in patients with brain swelling. We believe that continuous ventricular CSF drainage with ICP monitoring is a simple method as an adjunct in the management of these patients.

Prostaglandin E2 EP1 receptor inhibition fails to provide neuroprotection in surgically induced brain-injured mice

Recent trials have shown that the prostaglandin E2 EP1 receptor is responsible for NMDA excitotoxicity in the brain after injury. Consequently, in this study, we investigated the use of SC-51089, a selective prostaglandin E2 EP1 receptor antagonist, as a pre-treatment modality to decrease cell death, reduce brain edema, and improve neurobehavioral function after surgically induced brain injury (SBI) in mice. Eleven-week-old C57 black mice (n=82) were randomly assigned to four groups: sham (n=31), SBI (n=27), SBI treated with SC51089 at 10 μg/kg (n=7), and SBI treated with SC51089 at 100 μg/kg (n=17). Treated groups received a single dose of SC51089 intrapertioneally at 12 and 1 h pre-surgery. SBI was performed by resecting the right frontal lobe using a frontal craniotomy. Postoperative assessment occurred at 24 and 72 h, and included neurobehavioral testing and measurement of brain water content and cell death. Results indicated that neither low- nor high-dose EP1 receptor inhibition protected against the SBI-related effects on brain edema formation or cell death. There was however a significant improvement in neurobehavioral function 24 h post-SBI with both dosing regimens. Further studies will be needed to assess the potential therapeutic role of EP1 receptor targeting in SBI.

Imaging for the diagnosis and management of traumatic brain injury

To understand the role of imaging in traumatic brain injury (TBI), it is important to appreciate that TBI encompasses a heterogeneous group of intracranial injuries and includes both insults at the time of impact and a deleterious secondary cascade of insults that require optimal medical and surgical management. Initial imaging identifies the acute primary insult that is essential to diagnosing TBI, but serial imaging surveillance is also critical to identifying secondary injuries such as cerebral herniation and swelling that guide neurocritical management. Computed tomography (CT) is the mainstay of TBI imaging in the acute setting, but magnetic resonance tomography (MRI) has better diagnostic sensitivity for nonhemorrhagic contusions and shear-strain injuries. Both CT and MRI can be used to prognosticate clinical outcome, and there is particular interest in advanced applications of both techniques that may greatly improve the sensitivity of conventional CT and MRI for both the diagnosis and prognosis of TBI.

Pathophysiological response to experimental diffuse brain trauma differs as a function of developmental age

The purpose of experimental models of traumatic brain injury (TBI) is to reproduce selected aspects of human head injury such as brain edema, contusion or concussion, and functional deficits, among others. As the immature brain may be particularly vulnerable to injury during critical periods of development, and pediatric TBI may cause neurobehavioral deficits, our aim was to develop and characterize as a function of developmental age a model of diffuse TBI (DTBI) with quantifiable functional deficits. We modified a DTBI rat model initially developed by us in adult animals to study the graded response to injury as a function of developmental age - 7-, 14- and 21-day-old rats compared to young adult (3-month-old) animals. Our model caused motor deficits that persisted even after the pups reached adulthood, as well as reduced cognitive performance 2 weeks after injury. Moreover, our model induced prominent edema often seen in pediatric TBI, particularly evident in 7- and 14-day-old animals, as measured by both the wet weight/dry weight method and diffusion-weighted MRI. Blood-brain barrier permeability, as measured by the Evans blue dye technique, peaked at 20 min after trauma in all age groups, with a second peak found only in adult animals at 24 h after injury. Phosphorus MR spectroscopy showed no significant changes in the brain energy metabolism of immature rats with moderate DTBI, in contrast to significant decreases previously identified in adult animals.

Diffusion tensor imaging tractography in patients with intramedullary tumors: comparison with intraoperative findings and value for prediction of tumor resectability

Object

The aim of this retrospective study was to evaluate the predictive value of diffusion tensor (DT) imaging with respect to resectability of intramedullary spinal cord tumors and to determine the concordance of this method with intraoperative surgical findings.

Methods

Diffusion tensor imaging was performed in 14 patients with intramedullary lesions of the spinal cord at different levels using a 3-T magnet. Routine MR imaging scans were also obtained, including unenhanced and enhanced T1-weighted images and T2-weighted images. Patients were classified according to the fiber course with respect to the lesion and their lesions were rated as resectable or nonresectable. These results were compared with the surgical findings (existence vs absence of cleavage plane). The interrater reliability was calculated using the κ coefficient of Cohen.

Results

Of the 14 patients (7 male, 7 female; mean age 49.2 ± 15.5 years), 13 had tumors (8 ependymomas, 2 lymphomas, and 3 astrocytoma). One lesion was proven to be a multiple sclerosis plaque during further diagnostic workup. The lesions could be classified into 3 types according to the fiber course. In Type 1 (5 cases) fibers did not pass through the solid lesion. In Type 2 (3 cases) some fibers crossed the lesion, but most of the lesion volume did not contain fibers. In Type 3 (6 cases) the fibers were completely encased by tumor. Based on these results, 6 tumors were considered resectable, 7 were not. During surgery, 7 tumors showed a good cleavage plane, 6 did not. The interrater reliability (Cohen κ) was calculated as 0.83 (p < 0.003), which is considered to represent substantial agreement. The mean duration of follow-up was 12.0 ± 2.9. The median McCormick grade at the end of follow-up was II.

Conclusions

These preliminary data suggest that DT imaging in patients with spinal cord tumors is capable of predicting the resectability of the lesion. A further prospective study is needed to confirm these results and any effect on patient outcome.

Clinical presentation, histology, and treatment in 430 patients with primary tumors of the spinal cord, spinal meninges, or cauda equina

OBJECT Patients having a primary tumor of the spinal cord, spinal meninges or cauda equina, are relatively rare. Neurosurgeons encounter and treat such patients, and need to be aware of their clinical presentation, tumor types, treatment options, and potential complications. The purpose of this paper is to report results from a series of 430 patients with primary intraspinal tumors, taken from a larger cohort of 9661 patients with primary tumors of the CNS. METHODS Extensive information on individuals diagnosed (in the year 2000) as having a primary CNS neoplasm was prospectively collected in a Patient Care Evaluation Study conducted by the Commission on Cancer of the American College of Surgeons. Data from US hospital cancer registries were submitted directly to the National Cancer Database. Intraspinal tumor cases were identified based on ICD-O-2 topography codes C70.1, C72.0, and C72.1. Analyses were performed using SPSS. RESULTS Patients with primary intraspinal tumors represented 4.5% of the CNS tumor group, and had a mean age of 49.3 years. Pain was the most common presenting symptom, while the most common tumor types were meningioma (24.4%), ependymoma (23.7%), and schwannoma (21.2%). Resection, surgical biopsy, or both were performed in 89.3% of cases. Complications were low, but included neurological worsening (2.2%) and infection (1.6%). Radiation therapy and chemotherapy were administered to 20.3% and 5.6% of patients, respectively. CONCLUSIONS Data from this study are suitable for benchmarking, describing prevailing patterns of care, and generating additional hypotheses for future studies.

Ependymoma of the spinal cord in children and adolescents: a retrospective series from the HIT database

OBJECT

Reports on spinal cord ependymoma in children are rare. The aim of this study was to evaluate the clinical spectrum, treatment, and outcome of children with primary ependymoma of the spinal cord who were registered in the database of the pediatric German brain tumor studies Hirntumor (HIT) '91 and HIT 2000.

METHODS

Between 1991 and 2007, 29 patients (12 male and 17 female, median age at diagnosis 13.6 years) with primary spinal cord ependymoma (myxopapillary ependymoma WHO Grade I, II, and III tumors in 6, 17, and 6 patients, respectively) were identified. Four patients had neurofibromatosis Type 2.

RESULTS

With a median follow-up of 4.2 years (range 0.48-15 years), 28 patients (96.6%) were alive. Seven patients (24.1%) developed progressive disease or relapse, 2 after gross-total resection (GTR) and 5 after incomplete resection or biopsy. One patient with anaplastic ependymoma (WHO Grade III) died 65 months after diagnosis of disease progression. Primary adjuvant treatment (radiotherapy, chemotherapy, or both) was used in 8 (50%) of 16 patients following GTR and in 9 (82%) of 11 patients who underwent less than a GTR. Three additional patients were treated adjuvantly following progression. Estimated progression-free survival and overall survival rates at 5 years were 72.3% (95% CI 50%-86%) and 100%, respectively. Progression-free survival at 5 years is 84.4% (95% CI 50%-96%) for patients following GTR compared with 57.1% (95% CI 25%-69%) for patients who achieved a less than GTR (p = 0.088, log-rank test). A high relapse incidence (4 of 6) was observed among patients with myxopapillary ependymoma.

CONCLUSIONS

Gross-total resection is the mainstay of treatment for patients with primary spinal cord ependymoma and may be achieved in about 50% of the patients using modern surgical techniques. Primary adjuvant treatment was commonly used in children with spinal cord ependymoma irrespective of the extent of resection or tumor grade. The impact of adjuvant treatment on progression-free and overall survival has to be investigated in a prospective trial.

Cerebral blood volume alterations in the perilesional areas in the rat brain after traumatic brain injury--comparison with behavioral outcome

In the traumatic brain injury (TBI) the initial impact causes both primary injury, and launches secondary injury cascades. One consequence, and a factor that may contribute to these secondary changes and functional outcome, is altered hemodynamics. The relative cerebral blood volume (CBV) changes in rat brain after severe controlled cortical impact injury were characterized to assess their interrelations with motor function impairment. Magnetic resonance imaging (MRI) was performed 1, 2, 4 h, and 1, 2, 3, 4, 7, and 14 days after TBI to quantify CBV and water diffusion. Neuroscore test was conducted before, and 2, 7, and 14 days after the TBI. We found distinct temporal profile of CBV in the perilesional area, hippocampus, and in the primary lesion. In all regions, the first response was drop of CBV. Perifocal CBV was reduced for over 4 days thereafter gradually recovering. After the initial drop, the hippocampal CBV was increased for 2 weeks. Neuroscore demonstrated severely impaired motor functions 2 days after injury (33% decrease), which then slowly recovered in 2 weeks. This recovery parallelled the recovery of perifocal CBV. CBV MRI can detect cerebrovascular pathophysiology after TBI in the vulnerable perilesional area, which seems to potentially associate with time course of sensory-motor deficit.

Aquaporin-1-mediated cerebral edema following traumatic brain injury: effects of acidosis and corticosteroid administration

OBJECT

Dysregulation of water homeostasis induces cerebral edema. Edema is a major cause of morbidity and mortality following traumatic brain injury (TBI). Aquaporin-1 (AQP-1), a water channel found in the brain, can function as a transporter for CO2 across the cellular membrane. Additionally, AQP-1's promoter contains a glucocorticoid response element. Thus, AQP-1 may be involved with edema-related brain injury and might be modulated by external conditions such as the pH and the presence of steroids. In this study, the authors investigated the hypotheses that: 1) AQP-1 participates in brain water homeostasis following TBI; 2) secondary injury (for example, acidosis) alters the expression of AQP-1 and exacerbates cerebral edema; and 3) corticosteroids augment brain AQP-1 expression and differentially affect cerebral edema under nonacidotic and acidotic conditions.

METHODS

Anesthetized Sprague-Dawley rats were subjected to moderate to severe TBI (2.5-3.5 atm) or surgery without injury, and they were randomized to receive a 3-mg/kg bolus of intravenous dexamethasone within 10 minutes after injury or surgery, a 3-mg/kg bolus of dexamethasone followed by 1-mg/kg maintenance doses every 8 hours for 24 hours, or saline boluses at similar time intervals. A second group of animals was subjected to respiratory acidosis with target arterial blood pH 6.8-7.2 for 1 hour following the surgery or injury. To evaluate selective blockage of AQP-1, some animals received a single intraperitoneal dose of HgCl2 (0.3-30.0 mmol/L) within 30 minutes of injury or surgery. At 4 or 24 hours postinjury, animals were killed and their brains were harvested for mRNA, protein, or water content analyses.

RESULTS

The authors demonstrated elevated cerebral edema levels at 4 and 24 hours following TBI. Dexamethasone administration within 1 hour of TBI attenuated the cerebral edema under nonacidotic conditions but worsened it under acidotic conditions. Selective blockage of AQP-1 channels with HgCl2 attenuated the edematous effects of corticosteroids and acidosis. Reverse transcriptase polymerase chain reaction and immunohistochemical analyses demonstrated a paucity of AQP-1 in the cerebral cortices of the uninjured animals. In contrast, AQP-1 mRNA and protein levels were higher in the cerebral cortices of animals that sustained a TBI.

CONCLUSIONS

These findings implicate an important, modifiable role for AQP-1 in water homeostasis within the CNS following TBI.

The protein kinase C activator phorbol myristate acetate decreases brain edema by aquaporin 4 downregulation after middle cerebral artery occlusion in the rat

The protein kinase C activator phorbol 12-myristate 13-acetate (PMA) is known to interact with aquaporin 4 (AQP 4), a water-selective transporting protein that is abundant in astrocytes, and has experimentally been found to decrease osmotically-induced cell swelling. The purpose of this study was to examine whether PMA reduces brain edema following focal ischemia induced by middle cerebral artery (MCA) occlusion by modulation of AQP4 expression. Male Sprague-Dawley rats were randomly assigned to either sham surgery (n = 6), or a continuous intravenous infusion of vehicle (1% dimethylsulfoxide), followed by MCA occlusion (n = 18), and administration of PMA at 50 microg/kg (n = 6) or at 200 microg/kg (n = 6) starting 60 min before or 30 min (200 microg/kg; n = 6) or 60 min (200 microg/kg; n = 6) after MCA occlusion. Cerebral blood flow was monitored with laser Doppler over the MCA territory, and confirmed a 70% reduction during occlusion. After a 2-h period of ischemia and 2 h of reperfusion, the animals were sacrificed for assessment of brain water content and sodium and potassium concentration. AQP4 expression was assessed by immunoblotting and quantified by densitometry (n = 24). Statistical analysis was performed by ANOVA followed by Tukey's post-hoc test. PMA treatment at 200 microg/kg significantly reduced brain water concentration in the infarcted area when started 60 min before or 30 min after occlusion (p < 0.001 and p = 0.022, respectively), and prevented the subsequent sodium shift (p < 0.05). PMA normalized the AQP4 upregulation in ischemia (p = 0.021). A downregulation of AQP4 in the ischemic area paralleling the reduction in brain edema formation following PMA treatment suggests that the effect was mediated by AQP4 modulation.

Associations between cerebrospinal fluid protein concentrations, serum albumin concentrations and intracranial pressure in neurotrauma and intracranial haemorrhage

Recent evidence suggests that using intravenous isotonic albumin solution for haemodynamic resuscitation in neurotrauma is associated with adverse outcomes. This study assessed the correlations between cerebrospinal fluid protein concentrations, serum albumin concentrations and intracranial pressure in a cohort of neurosurgical patients. After obtaining ethics committee approval, correlations between concomitant cerebrospinal fluid protein concentrations, serum albumin concentrations and the mean daily intracranial pressure of 63 consecutive neurosurgical patients, grouped as neurotrauma or intracranial haemorrhage, admitted between 1 January and 31 December 2007, were assessed. The mean daily intracranial pressure was significantly associated with cerebrospinal fluid protein concentrations (Spearman correlation coefficient [SCC] = 0.496, P = 0.001), white cell counts (SCC = 0.359, P = 0.001), red cell counts (SCC = 0.399, P = .0O01) and serum albumin concentrations (SCC = 0.431, P = 0.001) in patients with neurotrauma (n=23). Cerebrospinal fluid protein concentrations were also significantly associated with concomitant serum albumin concentrations (SCC = 0.393, P = 0.001) in these patients. In patients with intracranial haemorrhage (n=40), the mean daily intracranial pressure was only significantly associated with cerebrospinal fluid white cell and red cell counts but not cerebrospinal fluid protein and serum albumin concentrations. In summary, intracranial pressure is correlated with cerebrospinal fluid protein and serum albumin concentrations in patients with severe neurotrauma, and these suggest that blood-brain barrier may not be completely intact after severe neurotrauma.

Reversible post-traumatic bilateral extensive restricted diffusion of the brain. A case study and review of the literature

PRIMARY OBJECTIVE

To increase the knowledge about diffuse traumatic brain injury (TBI) by reporting the magnetic resonance imaging (MRI) findings observed in a patient with reversible extensive restricted diffusion of the brain at diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps.

CASE STUDY

An 18-year-old patient was admitted after high-energy closed TBI. Glasgow Coma Scale score was 4. Head computed tomography showed small left frontal and temporal haemorrhagic contusions and a small haemorrhage in the left thalamus. Ten days later, brain MRI showed diffuse high-signal intensity on T2-weighted images and DWI and restricted diffusion in the subcortical white matter of both centri semiovali, genu and splenium of corpus callosum and parietal cortex bilaterally (mean ADC value = 0.434-0.811 x 10(-3) mm(2) s(-1)). Eleven days later, follow-up brain MRI showed gliotic changes in the left splenium of corpus callosum, a clearcut decrease of T2-weighted high-signal intensity and resolution of abnormalities at DWI and ADC maps in all other involved sites. This was confirmed 36 days later. Three months later, the patient did not show neurological, cognitive or neuropsychiatric deficits.

CONCLUSIONS

In the patient reported herein, closed TBI most likely induced diffuse excitotoxic injury of the brain which resulted in mainly reversible cytotoxic or intramyelinic oedema.

Substance P antagonists as a therapeutic approach to improving outcome following traumatic brain injury

Although a number of secondary injury factors are known to contribute to the development of morphological injury and functional deficits following traumatic brain injury, accumulating evidence has suggested that neuropeptides, and in particular substance P, may play a critical role. Substance P is released early following acute injury to the CNS as part of a neurogenic inflammatory response. In so doing, it facilitates an increase in the permeability of the blood-brain barrier and the development of vasogenic edema. At the cellular level, substance P has been shown to directly result in neuronal cell death; functionally, substance P has been implicated in learning and memory, mood and anxiety, stress mechanisms, emotion-processing, migraine, emesis, pain, and seizures, all of which may be adversely affected after brain injury. Inhibition of post-traumatic substance P activity, either by preventing release or by antagonism of the neurokinin-1 receptor, has consistently resulted in a profound decrease in development of edema and marked improvements in functional outcome. This review summarizes the current evidence supporting a role for substance P in acute brain injury.

Management of intramedullary spinal cord lesions: interdependence of the longitudinal extension of the lesion and the functional outcome

To evaluate the impact of the longitudinal extension of intramedullary lesions on the neurological status and postoperative outcome. Forty-six patients operated in our Department between February 2004 and June 2007 have been included in this study. The patients were classified in two groups according to the longitudinal extension of the lesion over less than three vertebral segments (group A) and over exactly three or more vertebral segments (group B). The neurological status was assessed preoperatively, postoperatively and after 3 months and involved both the McCormick (McC) and Klekamp-Samii (KS) scales. The preoperative McC- and KS scores of the patients of group B were statistically significant lower (p < 0.038 and p < 0.027, respectively) than those of group A. Patients of both groups showed an initial postoperative clinical deterioration. The level of statistical significance was reached only in group B (group A McC p < 0.170, KS p < 0.105; group B McC p < 0.012, KS p < 0.020). The patients recovered well and no statistical difference was observed between the preoperative and the 3-month follow-up scores (group A McC p < 0.490, KS p < 0.705; group B McC p < 0.506, KS p < 0.709). Thus, patients with extended intramedullary lesions have a worse neurological status preoperatively, postoperatively and in the 3-month follow-up. The preoperative neurostatus is determinant for the outcome. Even in case of longitudinally extensive intramedullary lesions, early surgery is recommended since satisfactory results can be achieved.

The BRAIN TRIAL: a randomised, placebo controlled trial of a Bradykinin B2 receptor antagonist (Anatibant) in patients with traumatic brain injury

Background

Cerebral oedema is associated with significant neurological damage in patients with traumatic brain injury. Bradykinin is an inflammatory mediator that may contribute to cerebral oedema by increasing the permeability of the blood-brain barrier. We evaluated the safety and effectiveness of the non-peptide bradykinin B2 receptor antagonist Anatibant in the treatment of patients with traumatic brain injury. During the course of the trial, funding was withdrawn by the sponsor.

Methods

Adults with traumatic brain injury and a Glasgow Coma Scale score of 12 or less, who had a CT scan showing an intracranial abnormality consistent with trauma, and were within eight hours of their injury were randomly allocated to low, medium or high dose Anatibant or to placebo. Outcomes were Serious Adverse Events (SAE), mortality 15 days following injury and in-hospital morbidity assessed by the Glasgow Coma Scale (GCS), the Disability Rating Scale (DRS) and a modified version of the Oxford Handicap Scale (HIREOS).

Results

228 patients out of a planned sample size of 400 patients were randomised. The risk of experiencing one or more SAEs was 26.4% (43/163) in the combined Anatibant treated group, compared to 19.3% (11/57) in the placebo group (relative risk = 1.37; 95% CI 0·76 to 2·46). All cause mortality in the Anatibant treated group was 19% and in the placebo group 15.8% (relative risk 1.20, 95% CI 0.61 to 2.36). The mean GCS at discharge was 12.48 in the Anatibant treated group and 13.0 in the placebo group. Mean DRS was 11.18 Anatibant versus 9.73 placebo, and mean HIREOS was 3.94 Anatibant versus 3.54 placebo. The differences between the mean levels for GCS, DRS and HIREOS in the Anatibant and placebo groups, when adjusted for baseline GCS, showed a non-significant trend for worse outcomes in all three measures.

Conclusion

This trial did not reach the planned sample size of 400 patients and consequently, the study power to detect an increase in the risk of serious adverse events was reduced. This trial provides no reliable evidence of benefit or harm and a larger trial would be needed to establish safety and effectiveness.

Trial Registration

This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN23625128.

Surgical treatment of one hundred seventy-four intramedullary spinal cord tumors

STUDY DESIGN

A retrospective study of microsurgical treatment of intramedullary spinal cord tumors (IMSCT) was conducted.

OBJECTIVE

In this article we review our experience in dealing with IMSCTs and try to answer the question of the optimum treatment of IMSCTs.

SUMMARY OF BACKGROUND DATA

IMSCTs are commonly seen tumors in intraspinal tumors. The optimum treatment of those tumors is controversial, with the recent advance, the operation of IMSCTs has became safer and total resection of most those tumor is possible.

METHODS

Data from 174 IMSCTs operated on in the last 20 years are analyzed retrospectively by the tumors' anatomic locations, histologic types, symptoms and signs, tumor removal rate, and operative outcomes.

RESULTS

In this group ependymoma was the commonest tumor (48.9%), the second most often seen being astrocytoma (35.6%). On admission 142 patients suffered from motor disturbance and 134 from dysaesthesia. Eighty-eight had sphincter disturbance and 100 spontaneous pain. Total resection of the tumor was possible in 60.9% of patients, subtotal resection in 17.2%, and partial resection in 13.8%. In patients with ependymoma total resection was possible in 92.9% of patients, subtotal in 5.95%, and partial resection in 1.2%. In low grade astrocytoma total resection was possible in 41.1%, subtotal in 35.1%, and partial resection in 23.2%. There were 6 patients with malignant astrocytomata; total resection was possible in 1 patient, subtotal resection in 2, and partial resection in 3.In the other tumors total resection was possible in 63% and subtotal in 14.8%, in 23.2% was partial resection possible. Six months after operation the patient's symptoms and signs were compared with those before operation. Neurologic deficits had improved in 60.4%, there was no change in 36.2% and deterioration in 3.4%. On long-term follow-up there was improvement in 70.2%, no change in 19.5%, deterioration in 4%, tumor recurrence in 6.9%, with 6.3% of patients dying.

CONCLUSION

Most intramedullary spinal cord tumors need operative treatment as early as possible. The outcome of aggressive surgery now is much better than it has been in the past, and the results are acceptable. For malignant tumors and those where total removal has not been possible radiation therapy is necessary.

Surgical considerations of spinal ependymomas in the pediatric population

OBJECTIVES

The objective of this manuscript is to discuss current management strategies regarding pediatric patients with intramedullary spinal cord ependymomas. Spinal ependymoma is the second most common spinal cord tumor in children. The clinical evaluation of these patients, operative techniques, postoperative management considerations, and long-term outcomes are discussed.

INTRODUCTION

The gold standard for the treatment of spinal ependymoma continues to be gross total resection. Patients with residual tumor postoperatively may benefit from adjuvant radiation therapy. Intraoperative monitoring is critical to minimize permanent postoperative neurologic deficit.

CONCLUSION

Patients requiring multilevel laminectomy may benefit from concomitant laminoplasty or instrumented fusion to avoid progressive spinal column deformity.

Modern approaches to pediatric brain injury therapy

Each year, pediatric traumatic brain injury (TBI) accounts for 435,000 emergency department visits, 37,000 hospital admissions, and approximately 2,500 deaths in the United States. TBI results in immediate injury from direct mechanical force and shear. Secondary injury results from the release of biochemical or inflammatory factors that alter the loco-regional milieu in the acute, subacute, and delayed intervals after a mechanical insult. Preliminary preclinical and clinical research is underway to evaluate the benefit from progenitor cell therapeutics, hypertonic saline infusion, and controlled hypothermia. However, all phase III clinical trials investigating pharmacologic monotherapy for TBI have shown no benefit. A recent National Institutes of Health consensus statement recommends research into multimodality treatments for TBI. This article will review the complex pathophysiology of TBI as well as the possible therapeutic mechanisms of progenitor cell transplantation, hypertonic saline infusion, and controlled hypothermia for possible utilization in multimodality clinical trials.

Prognostic factors in intramedullary astrocytomas: a literature review

Astrocytomas affect a significant portion of patients with intramedullary tumors. These infiltratively growing tumors are treated by a variety of methods -- biopsy and decompressive surgery, maximal safe resection, adjuvant oncological therapy. Also, numerous prognostic factors are reported in the literature. Better understanding of factors that influence prognosis may help in treatment planning with the goal of prolonging survival. We have thus undertaken an extensive literature review in order to define factors affecting prognosis. A total of 38 articles were studied. Only tumor grade was consistently reported as the major factor affecting prognosis. The influence of other clinical factors (age, gender, history length, functional status, tumor location or extent, syrinx or cyst presence) can be speculated upon, but cannot be assessed adequately from the available literature. For both low- and high-grade (HG) astrocytomas, maximal safe tumor resection should be the primary treatment objective but is often not feasible in contrast to other intramedullary and spinal neoplasms. Since the biological nature of spinal cord HG glioma is identical to that of the brain, the same treatment algorithm of maximal safe resection followed by concomitant radio- and chemotherapy would be sensible to implement.

Primary spinal cord tumors of childhood: effects of clinical presentation, radiographic features, and pathology on survival

To determine the relationship between clinical presentation, radiographic features, pathology, and treatment on overall survival of newly diagnosed pediatric primary spinal cord tumors (PSCT). Retrospective analysis of all previously healthy children with newly diagnosed PSCT at a single institution from 1995 to present was performed. Twenty-five pediatric patients (15 boys, average 7.9 years) were diagnosed with PSCT. Presenting symptoms ranged from 0.25 to 60 months (average 7.8 months). Symptom duration was significantly shorter for high grade tumors (average 1.65 months) than low grade tumors (average 11.2 months) (P = 0.05). MRI revealed tumor (8 cervical, 17 thoracic, 7 lumbar, 7 sacral) volumes of 98–94,080 mm³ (average 19,474 mm³). Homogeneous gadolinium enhancement on MRI correlated with lower grade pathology (P = 0.003). There was no correlation between tumor grade and volume (P = 0.63) or edema (P = 0.36) by MRI analysis. Median survival was 53 months and was dependent on tumor grade (P = 0.05) and gross total resection (P = 0.01) but not on gender (P = 0.49), age of presentation (P = 0.82), duration of presenting symptoms (P = 0.33), or adjuvant therapies (P = 0.17). Stratified Kaplan–Meier analysis confirmed the association between degree of resection and survival after controlling for tumor grade (P = 0.01). MRI homogeneous gadolinium enhancement patterns may be helpful in distinguishing low grade from high grade spinal cord malignancies. While tumor grade and gross total resection rather than duration of symptoms correlated with survival in our series, greater than one-third of patients had reported symptoms greater than 6 months duration prior to diagnosis.

Surgical results of intramedullary spinal cord tumor with spinal cord monitoring to guide extent of resection

Object

The authors investigated the outcome of intramedullary spinal cord tumor surgery, focusing on the effect of preoperative neurological status on postoperative mobility and the extent of tumor excision guided by intraoperative spinal cord monitoring prospectively.

Methods

Intramedullary spinal cord tumor surgery was performed in 131 patients between 1997 and 2007. The authors compared the pre- and postoperative neurological status and examined the type of surgery in 106 of these patients. A modified McCormick Scale (Grades I–V) was used to assess ambulatory ability (I = normal ambulation; II = mild motor sensory deficit, independent without external aid; III = independent with external aid; IV = care required; and V = wheelchair required). The type of surgery was classified into 4 levels: total resection, subtotal resection, partial resection, and biopsy.

Results

The 106 patients consisted of 47 females and 59 males, whose average age was 42.5 years (range 6–75 years). The mean follow-up period was 7.3 years (range 2.5 months–21 years). The tumor types included astrocytoma (12 cases), ependymoma (46 cases), hemangioblastoma (16 cases), cavernous hemangioma (17 cases), and others (15 cases overall: gangliocytoma, 1; germ cell tumor, 1; lymphoma, 3; neurinoma, 1; meningioma, 1; oligodendroglioma, 1; sarcoidosis, 2; glioma, 1; and unknown, 4). Initial total excision, subtotal resection, partial resection, biopsy, and duraplasty were performed in 59, 12, 22, 12, and 1 patients, respectively. According to the preoperative McCormick Scale, ambulatory status was classified as Grades I, II, III, IV, and V in 41(38%), 30 (28%), 14 (13%), 19 (19%), and 2 (2%) patients, respectively. Thirty-three (31%) of 106 patients suffered postoperative neurological deterioration. The number of patients who did not lose ambulatory ability or who achieved an ambulatory status of Grade I or II postoperatively was 33 (80%), 21 (70%), 10 (71%), 8 (42%), and 1 (50%) in patients with preoperative Grades I, II, III, IV, and V, respectively. Total excision was performed in 31 (79%) of 39 patients with preoperative Grade I, 12 (40%) of 30 patients with Grade II, 7 (50%) of 14 patients with Grade III, and 9 of 21 patients (38%) with Grade IV or V, indicating that the rate of total excision was significantly higher in patients with Grade I status.

Conclusions

The postoperative ambulatory ability was excellent in patients with a good preoperative neurological status. Total excision in patients with Grade I or II ambulation was associated with a good prognosis for postoperative mobility. However, the rate of postoperative deterioration was 31.5%, which is relatively high, and patients should be fully informed of this concern prior to intramedullary spinal cord tumor surgery.

Management of intracranial hypertension

Raised intracranial pressure (ICP) is a life threatening condition that is common to many neurological and non-neurological illnesses. Unless recognized and treated early it may cause secondary brain injury due to reduced cerebral perfusion pressure (CPP), and progress to brain herniation and death. Management of raised ICP includes care of airway, ventilation and oxygenation, adequate sedation and analgesia, neutral neck position, head end elevation by 20 degrees-30 degrees, and short-term hyperventilation (to achieve PCO(2) 32-35 mm Hg) and hyperosmolar therapy (mannitol or hypertonic saline) in critically raised ICP. Barbiturate coma, moderate hypothermia and surgical decompression may be helpful in refractory cases. Therapies aimed directly at keeping ICP <20 mmHg have resulted in improved survival and neurological outcome. Emerging evidence suggests that cerebral perfusion pressure targeted therapy may offer better outcome than ICP targeted therapies.

Early metabolic characteristics of lesion and nonlesion tissue after head injury

We defined lesion and structurally normal regions using magnetic resonance imaging at follow-up in patients recovering from head injury. Early metabolic characteristics in these regions of interest (ROIs) were compared with physiology in healthy volunteers. Fourteen patients with severe head injury had positron emission tomography within 72 h, and magnetic resonance imaging at 3 to 18 months after injury. Cerebral blood flow (CBF), oxygen utilization (CMRO(2)), and oxygen extraction fraction (OEF) were all lower in lesion ROIs, compared with nonlesion and control ROIs (P<0.001); however, there was substantial overlap in physiology. Control ROIs showed close coupling among CBF, blood volume (CBV), and CMRO(2), whereas relationships within lesion and nonlesion ROIs were abnormal. The relationship between CBF and CMRO(2) generally remained coupled but the slope was reduced; that for CBF and OEF was variable; whereas that between CBF and CBV was highly variable. There was considerable heterogeneity between and within patients. Although irreversibly damaged tissue is characterized by marked derangements in physiology, a more detailed analysis shows acute changes in physiology and physiologic relationships within regions of the brain that appear structurally normal at follow-up. Such pathophysiological derangements may result in selective neuronal loss and impact on functional outcome.

Predictors for functional recovery and mortality of surgically treated traumatic acute subdural hematomas in 256 patients

OBJECTIVE

The purpose of this study was to investigate the reliable factors influencing the surgical outcome of the patients with traumatic acute subdural hematoma (ASDH) and to improve the functional outcome of these patients.

METHODS

A total of 256 consecutive patients who underwent surgical intervention for traumatic ASDH between March 1998 and March 2008 were reviewed. We evaluated the influence of perioperative variables on functional recovery and mortality using multivariate logistic regression analysis.

RESULTS

Functional recovery was achieved in 42.2% of patients and the overall mortality was 39.8%. Age (OR=4.91, p=0.002), mechanism of injury (OR=3.66, p=0.003), pupillary abnormality (OR=3.73, p=0.003), GCS score on admission (OR=5.64, p=0.000), and intraoperative acute brain swelling (ABS) (OR=3.71, p=0.009) were independent predictors for functional recovery. And preoperative pupillary abnormality (OR=2.60, p=0.023), GCS score (OR=4.66, p=0.000), and intraoperative ABS (OR=4.16, p=0.001) were independent predictors for mortality. Midline shift, thickness and volume of hematoma, type of surgery, and time to surgery showed no independent association with functional recovery, although these variables were correlated with functional recovery in univariate analyses.

CONCLUSION

Functional recovery was more likely to be achieved in patients who were under 40 years of age, victims of motor vehicle collision and having preoperative reactive pupils, higher GCS score and the absence of ABS during surgery. These results would be helpful for neurosurgeon to improve outcomes from traumatic acute subdural hematomas.

Correlation of a preoperative grading scale with progressive spinal deformity following surgery for intramedullary spinal cord tumors in children

OBJECT

Postoperative progressive spinal deformity often complicates functional outcome after resection of pediatric intramedullary spinal cord tumors (IMSCTs). The authors propose a preoperative grading scale that correlates with the postoperative development of progressive spinal deformity requiring subsequent fusion.

METHODS

The data obtained in 164 patients who underwent resection of an IMSCT at a single institution were retrospectively collected and analyzed to determine the development of progressive spinal deformity requiring fusion. A grading scale (range of scores I-V) was created based on the presence or absence of 4 preoperative variables: preoperative scoliosis, involvement of the thorocolumbar junction, age<13 years, and number of surgeries for an IMSCT. The grading scale was then retrospectively applied to this series of 164 children to assess the correlation of variables with subsequent spinal deformity.

RESULTS

Nine patients presented with Grade I status, 41 patients with Grade II, 58 patients with Grade III, 44 patients with Grade IV, and 12 patients with Grade V. Overall, 44 patients (27%) developed progressive spinal deformity requiring fusion at a mean follow-up of 5 years after surgery. A higher preoperative grade was associated with an increasing need for subsequent fusion for progressive spinal deformity (Grade I [0%], Grade II [5%], Grade III [26%], Grade IV [40%], and Grade V status [75%]).

CONCLUSIONS

Application of this grading scheme to a series of resected pediatric IMSCTs has demonstrated its correlation with the incidence of postoperative progressive spinal deformity requiring fusion. The application of a standardized grading scheme will assist in the process of surgical decision making and postoperative evaluation.

Surgical treatment of primary spinal tumors in the conus medullaris

OBJECTIVE

The objective of this study was to evaluate the characteristics and surgical outcome of the conus medullaris tumors.

METHODS

We retrospectively reviewed 26 patients who underwent surgery for conus medullaris tumor from August 1986 to July 2007. We analyzed clinical manifestation, preoperative MRI findings, extent of surgical resection, histopathologic type, adjuvant therapy, and outcomes.

RESULTS

There were ependymoma (13), hemangioblastoma (3), lipoma (3), astrocytoma (3), primitive neuroectodermal tumor (PNET) (2), mature teratoma (1), and capillary hemangioma (1) on histopathologic type. Leg pain was the most common symptom and was seen in 80.8% of patients. Pain or sensory change in the saddle area was seen in 50% of patients and 2 patients had severe pain in the perineum and genitalia. Gross total or complete tumor resection was obtained in 80.8% of patients. On surgical outcome, modified JOA score worsened in 26.9% of patients, improved in 34.6%, and remained stable in 38.5%. The mean VAS score was improved from 5.4 to 1.8 among 21 patients who had lower back pain and leg pain.

CONCLUSION

The surgical outcome of conus medullaris tumor mainly depends on preoperative neurological condition and pathological type. The surgical treatment of conus medullaris tumor needs understanding the anatomical and functional characteristics of conus meudllaris tumor for better outcome.

Microsurgical removal of intramedullary spinal cord gliomas in a rat spinal cord decreases onset to paresis, an animal model for intramedullary tumor treatment

OBJECTIVE

Intramedullary spinal cord tumors (IMSCT) pose significant challenges given their recurrence rate and limited treatment options. Using our previously described rat model of IMSCT, we describe a technique for microsurgical tumor resection and present the functional and histopathological analysis of tumor progression.

METHODS

Twenty-four Fischer 344 rats were randomized into two groups. All animals received a 5-microl intramedullary injection of 9L gliosarcoma cells. Animals were evaluated daily for signs of paralysis using the Basso, Beattie, and Bresnahan (BBB) scale. Group 1 continued with daily assessments using the BBB scale following tumor implantation, but received no further treatment. Group 2 underwent surgical removal of intramedullary tumor on postoperative day five. At a BBB score less than 5 (e.g., functional paraplegia), all animals of both groups were killed and sent for histopathological analysis.

RESULTS

Group 1 had a median onset of functional hind limb paraplegia at 15 +/- 1.0 days. Group 2 had a median onset of hind limb paresis at 53 +/- 0.46 days. Hematoxylin-eosin cross-sections confirmed the presence of intramedullary 9L tumor invading the spinal cord in both groups.

CONCLUSION

Animals with 9L IMSCTs consistently developed hind limb paraplegia in a reliable and reproducible manner. Animals undergoing microsurgical resection of IMSCT had a significant delay in the onset of functional paraplegia compared to the untreated controls. These findings suggest that this model may mimic the behavior of IMSCTs following operative resection in humans and thus may be used to examine efficacy of new treatment options for high-grade intramedullary tumors.

The effect of haematoma, brain injury, and secondary insult on brain swelling in traumatic acute subdural haemorrhage

OBJECTIVE

The high mortality of acute subdural haematoma (ASDH) is largely explained by its frequent association with primary brain damage consisting of contusion and brain swelling. However, the nature and causes of brain swelling after traumatic brain injury are multifactorial and poorly understood. The purpose of this study was to investigate the pathophysiology of brain swelling associated with ASDH in traumatic brain injury.

METHODS

We examined whether the thickness of the haematoma, parenchymal injury, or presence of a secondary insult had an effect on traumatic brain swelling. The variables that might affect the pathophysiology of ASDH were examined, including: (1) age and mechanism of injury, (2) neurological findings, (3) secondary insult and extracranial injuries, (4) pre-operative computed tomography (CT) scan results, and (5) outcome.

RESULTS

A total of 212 patients were included in this study. On CT scan, 159 patients (75.0%) did not have brain swelling, 29 (13.7%) had hemispheric brain swelling, and 24 (11.3%) had diffuse brain swelling. Brain swelling associated with ASDH is caused by secondary insult in addition to parenchymal injury. In the present study, the outcome of ASDH associated with brain swelling was poor, even when treated with early surgical evacuation; the mortality rate of such patients was over 75%.

CONCLUSIONS

Given our findings, it is possible that the poor outcome of ASDH patients depends not only on the characteristics of the haematoma itself, but also on the presence of additional cerebral parenchymal injury and secondary insult.

Spinal deformity after resection of cervical intramedullary spinal cord tumors in children

OBJECTIVE

Progressive spinal deformity after cervical intramedullary spinal cord tumor (IMSCT) resection requiring subsequent fusion occurs in many cases among pediatric patients. It remains unknown which subgroups of patients represent the greatest risk for progressive spinal deformity.

MATERIALS AND METHODS

The data for 58 patients undergoing surgical resection of cervical IMSCT at a single institution were retrospectively collected and analyzed for development of progressive spinal deformity requiring fusion. The association of all clinical, radiographic, and operative variables to subsequent progressive spinal deformity as a function of time was assessed via Kaplan-Meier plots and Log-rank and Cox analyses.

RESULTS

Mean age at the time of surgery was 11 +/- 6 years. Eleven (19%) patients required subsequent fusion for progressive spinal deformity at a median [interquartile range (IQR)] of 4 (2-6) years after IMSCT resection. Five (36%) of 14 patients with preoperative scoliosis or loss of lordosis developed postoperative progressive spinal deformity compared to only 6 (13%) of 44 patients with normal preoperative sagittal and coronal balance, p = 0.06. Patients <13 years of age were more than three times more likely to develop postoperative progressive deformity, p = 0.05. Decompression spanning both the axial cervical spine (C1-C2) and the cervico-thoracic junction (C7-T1) increased the risk for progressive spinal deformity fourfold, p = 0.04. Number of spinal levels decompressed, revision surgery, radiotherapy, involvement of C1-C2 or C7-T1 alone in the decompression, or any other recorded variables were not associated with progressive postoperative spinal deformity.

CONCLUSION

Patients possessing one or more of these characteristics should be monitored closely for progressive spinal deformity after surgery.

Management of intracranial hypertension

Effective management of intracranial hypertension involves meticulous avoidance of factors that precipitate or aggravate increased intracranial pressure. When intracranial pressure becomes elevated, it is important to rule out new mass lesions that should be surgically evacuated. Medical management of increased intracranial pressure should include sedation, drainage of cerebrospinal fluid, and osmotherapy with either mannitol or hypertonic saline. For intracranial hypertension refractory to initial medical management, barbiturate coma, hypothermia, or decompressive craniectomy should be considered. Steroids are not indicated and may be harmful in the treatment of intracranial hypertension resulting from traumatic brain injury.

Matrix metalloproteinase inhibition attenuates brain edema in an in vivo model of surgically-induced brain injury

OBJECTIVE

Neurosurgical procedures can result in brain injury by various means, including direct trauma, hemorrhage, retractor stretch, and electrocautery. This surgically-induced brain injury (SBI) can cause postoperative complications such as brain edema after blood-brain barrier (BBB) disruption. The present study seeks to test a matrix metalloproteinase (MMP) inhibitor for preventing postoperative brain edema and BBB disruption in an in vivo model of surgically-induced brain injury.

METHODS

A rodent model of SBI was used which involves resection of a part of the right frontal lobe. A total of 89 Sprague-Dawley male rats (weight, 300-350 g) were randomly divided into four groups: 1) SBI with vehicle treatment (0.1% dimethyl sulfoxide), 2) SBI with single treatment of MMP inhibitor-1 (an inhibitor of MMP-9 and MMP-2), 3) SBI treated daily (total 3 times) with MMP inhibitor-1, and 4) sham surgical group. Postoperative assessment at different time periods included evaluation of BBB permeability, brain water content (brain edema), neurological scoring, histology, immunohistochemistry, and zymography for MMP enzymatic activity. Temporal magnetic resonance imaging studies were also performed to assess postoperative edema.

RESULTS

The results indicate that SBI caused increased brain water content (ipsilateral frontal lobe) and BBB permeability compared with sham animals. Treatment with MMP inhibitor-1 attenuated MMP-9 and MMP-2 activity and decreased brain water content with preservation of the BBB.

CONCLUSION

Inhibition of MMP-9 and MMP-2 attenuates brain edema and BBB disruption after SBI. The study suggests a potential role for MMP inhibition as preoperative therapy before neurosurgical procedures.

Incidence of spinal deformity after resection of intramedullary spinal cord tumors in children who underwent laminectomy compared with laminoplasty

OBJECT

Gross-total resection of pediatric intramedullary spinal cord tumor (IMSCT) can be achieved in the majority of cases while preserving long-term neurological function. Nevertheless, postoperative progressive spinal deformity often complicates functional outcome years after surgery. The authors set out to determine whether laminoplasty in comparison with laminectomy has reduced the incidence of subsequent spinal deformity requiring fusion after IMSCT resection at their institution.

METHODS

The first 144 consecutive patients undergoing resection of IMSCTs at a single institution underwent laminectomy with preservation of facet joints. The next 20 consecutive patients presenting for resection of IMSCTs underwent osteoplastic laminotomy regardless of patient or tumor characteristics. All patients were followed up with telephone interviews corroborated by medical records for the following outcomes: 1) neurological and functional status (modified McCormick Scale [MMS] score and Karnofsky Performance Scale [KPS] score); and 2) development of progressive spinal deformity requiring fusion. The incidence of progressive spinal deformity and the long-term neurological function were compared between the laminectomy and osteoplastic laminotomy cohorts. The means are expressed +/- the standard deviation.

RESULTS

Overall, the patients' mean age was 8.6 +/- 5 years, and they presented with median MMS scores of 2 (interquartile range [IQR] 2-4). A > 95% resection was achieved in 125 cases (76%). There were no differences (p > 0.10) between patients treated with osteoplastic laminotomy and those treated with laminectomy in terms of the following characteristics: age; sex; duration of symptoms; location of tumor; incidence of preoperative scoliosis (Cobb angle > 10 degrees : 7 [35%] with laminoplasty compared with 49 [34%] with laminectomy); involvement of the cervicothoracic junction (7 [35%] compared with 57 [40%]); thoracolumbar junction (4 [20%] compared with 36 [25%]); tumor size; extent of resection; radiation therapy; histopathological findings; or mean operative spinal levels (7.5 +/- 2 compared with 7.5 +/- 3). Nevertheless, patients who underwent osteoplastic laminotomy had better median preoperative MMS scores than those treated with laminectomy (2 [IQR 2-2] compared with 2 [IQR 2-4]; p = 0.04). A median of 3.5 years (IQR 1-7 years) after surgery, only 1 patient (5%) in the osteoplastic laminotomy cohort required fusion for progressive spinal deformity, compared with 43 (30%) in the laminectomy cohort (p = 0.027). Adjusting for the inter-cohort difference in preoperative MMS scores, osteoplastic laminotomy was associated with a 7-fold reduction in the odds of subsequent fusion for progressive spinal deformity (odds ratio 0.13, 95% confidence interval 0.02-1.00; p = 0.05). The median MMS and KPS scores were similar between patients who underwent osteoplastic laminotomy and those in whom laminectomy was performed (MMS Score 2 [IQR 2-3] for laminotomy compared with 2 [IQR 2-4] for laminectomy, p = 0.54; KPS Score 90 [IQR 70-100] for laminotomy compared with 90 [IQR 80-90] for laminectomy, p = 0.545) at a median of 3.5 years after surgery.

CONCLUSIONS

In the authors' experience, osteoplastic laminotomy for the resection of IMSCT in children was associated with a decreased incidence of progressive spinal deformity requiring fusion but did not affect long-term functional outcome. Laminoplasty used for pediatric IMSCT resection may decrease the incidence of progressive spinal deformity requiring subsequent spinal stabilization in some patients.

Assessment of mitochondrial impairment in traumatic brain injury using high-resolution proton magnetic resonance spectroscopy

Object

The goal of this study was to demonstrate the posttraumatic neurochemical damage in normal-appearing brain and to assess mitochondrial dysfunction by measuring N-acetylaspartate (NAA) levels in patients with severe head injuries, using proton (1H) magnetic resonance (MR) spectroscopy.

Methods

Semiquantitative analysis of NAA relative to creatine-containing compounds (Cr) and choline (Cho) was carried out from proton spectra obtained by means of chemical shift (CS) imaging and single-voxel (SV) methods in 25 patients with severe traumatic brain injuries (TBIs) (Glasgow Coma Scale scores ≤ 8) using a 1.5-tesla MR unit. Proton MR spectroscopy was also performed in 5 healthy volunteers (controls).

Results

The SV studies in patients with diffuse TBI showed partial reduction of NAA/Cho and NAA/Cr ratios within the first 10 days after injury (means ± standard deviations 1.59 ± 0.46 and 1.44 ± 0.21, respectively, in the patients compared with 2.08 ± 0.26 and 2.04 ± 0.31, respectively, in the controls; nonsignificant difference). The ratios gradually declined in all patients as time from injury increased (mean minimum values NAA/Cho 1.05 ± 0.44 and NAA/Cr 1.05 ± 0.30, p < 0.03 and p < 0.02, respectively). This reduction was greater in patients with less favorable outcomes. In patients with focal injuries, the periphery of the lesions revealed identical trends of NAA/Cho and NAA/Cr decrease. These reductions correlated with outcome at 6 months (p < 0.01). Assessment with multivoxel methods (CS imaging) demonstrated that, in diffuse injury, NAA levels declined uniformly throughout the brain. At 40 days postinjury, initially low NAA/Cho levels had recovered to near baseline in patients who had good outcomes, whereas no recovery was evident in patients with poor outcomes (p < 0.01).

Conclusions

Using 1H-MR spectroscopy, it is possible to detect the posttraumatic neurochemical damage of the injured brain when conventional neuroimaging techniques reveal no abnormality. Reduction of NAA levels is a dynamic process, evolving over time, decreasing and remaining low throughout the involved tissue in patients with poor outcomes. Recovery of NAA levels in patients with favorable outcomes suggests marginal mitochondrial impairment and possible resynthesis from vital neurons.

Neurological outcome after resection of intramedullary spinal cord tumors in children

OBJECTIVE

With modern surgical advances, radical resection of pediatric intramedullary spinal cord tumors (IMSCT) can be achieved with preservation of long-term neurological function. Clinical and radiographic risk factors predictive of postoperative neurological outcome may serve as a guide for surgical risk stratification.

MATERIALS AND METHODS

We prospectively reviewed the outcomes of 16 consecutive cases of pediatric IMSCT resection at a single institution. Clinical, radiographic, and operative variables were analyzed as predictors of postoperative neurological function defined by the modified McCormick score (MMS).

RESULTS

Sixteen children 10 +/- 5 years old presented with median (interquartile range) MMS score of 2 (1-2) with IMSCTs (eight cervical, eight thoracic) involving 4 +/- 2 levels. Pathology revealed astrocytoma in 12 cases (three pilocytic, four grade II, three grade III, two GBM), gangliogliomas in two, ependymoma in one, and gliosis in one case. At median follow-up of 7 months, six (38%) patients experienced improved neurological function, eight (50%) remained stable, one (6%) experienced a delayed decrease in neurological function (GBM progression), and one (6%) died (GBM progression). Five (31%) patients developed persistent dysesthetic symptoms. Four (80%) patients with cystic tumors experienced neurological improvement compared to only two (18%) patients with noncystic tumors, p < 0.05. Preoperative steroid use (odds ratio, OR [95% confidence interval, CI] = 18.0 [1.24-260.1], p = 0.03) and cystic tumor (OR [95%CI] = 18.0 [1.24-260.1], p = 0.03) predicted neurological improvement after surgery.

CONCLUSION

Radical resection of pediatric IMSCTs can be achieved with low incidence of neurological injury. Sensory syndromes frequently occur after pediatric IMSCT resection and frequently affect patient's quality of life. Tumors with compressive cysts may identify patients more likely to experience improved neurological function after surgical resection.

Monitoring intracranial pressure in traumatic brain injury

Increased intracranial pressure (ICP) is an important cause of secondary brain injury, and ICP monitoring has become an established component of brain monitoring after traumatic brain injury. ICP cannot be reliably estimated from any specific clinical feature or computed tomography finding and must actually be measured. Different methods of monitoring ICP have been described but intraventricular catheters and microtransducer systems are most widely used in clinical practice. ICP is a complex variable that links ICP and cerebral perfusion pressure and provides additional information from identification and analysis of pathologic ICP wave forms. ICP monitoring can also be augmented by measurement of indices describing cerebrovascular pressure reactivity and pressure-volume compensatory reserve. There is considerable variability in the use of ICP monitoring and treatment modalities among head injury centers. However, there is a large body of clinical evidence supporting the use of ICP monitoring to detect intracranial mass lesions early, guide therapeutic interventions, and assess prognosis, and it is recommended by consensus guidelines for head injury management. There remains a need for a prospective, randomized, controlled trial to identify the value of ICP monitoring and management after head injury.

Resection of intramedullary spinal cord tumors in children: assessment of long-term motor and sensory deficits

OBJECT

With modern surgical advances, radical resection of pediatric intramedullary spinal cord tumors (IMSCTs) can be expected to preserve long-term neurological function. Nevertheless, postoperative neurological decline is not uncommon after surgery, and many patients continue to experience long-term dysesthetic symptoms. Preoperative predictors of postoperative neurological decline and sensory syndromes have not been investigated and may serve as a guide for surgical risk stratification.

METHODS

Neurological function (as determined using the modified McCormick Scale [mMS]) preoperatively, postoperatively, and 3 months after surgery was retrospectively recorded from patient charts in 164 consecutive patients undergoing resection of IMSCTs. A median 4 years (interquartile range [IQR] 1-8 years) after surgery, long-term motor and sensory symptoms were assessed by telephone interviews and corroborated by subsequent medical visits in 120 available patients. This long-term assessment was retrospectively reviewed for the purposes of this study. The authors reviewed this series to assess long-term motor, sensory, and urinary outcomes and to determine independent risk factors of postoperative neurological decline and long-term sensory dysfunction.

RESULTS

Patients were 8.6 +/- 5.7 years old and presented with a median mMS of 2 (IQR 2-4). Three months after surgery, 38 patients (23%) continued to experience decreased neurological function (1 mMS point) incurred perioperatively. Increasing age (p = 0.028), unilateral symptoms (p = 0.046), and urinary dysfunction at presentation (p = 0.004) independently predicted persistent 3-month perioperative decline. At long-term follow-up (median 4 years), 39 (33%) exhibited improvements in their mMS scores, 13 (30%) had improvement in their urinary dysfunction, and 27 (30%) had resolution of their dysesthesias. Seventy-eight patients (65%) experienced long-term dysesthetic symptoms. Increasing age (p = 0.024), preoperative symptom duration > 12 months (p = 0.027), and worsened postoperative mMS score at hospital discharge (p = 0.013) independently increased the risk of long-term dysesthesias.

CONCLUSIONS

In the authors' experience, nearly one third of patients may experience improvement in motor, sensory, and urinary dysfunction years after IMSCT resection, whereas the majority will continue to experience long-term dysesthetic symptoms. Improvement in motor deficits preceded improvement in sensory syndromes, and urinary dysfunction typically resolved much longer after surgery. The risk of persistent perioperative motor decline was increased with older age, unilateral symptoms, preoperative urinary symptoms, and less severe preoperative neurological deficit. The risk of long-term dysesthesias was increased with older age, increased duration of symptoms prior to resection, and greater postoperative neurological deficit.

Perfusional deficit and the dynamics of cerebral edemas in experimental traumatic brain injury using perfusion and diffusion-weighted magnetic resonance imaging

The aim of this work was to characterize edema dynamics, cerebral blood volume, and flow alterations in an experimental model of brain trauma using quantitative diffusion and perfusion magnetic resonance imaging (MRI). Associated with an influx of water in the intracellular space 1-5 h post-trauma as demonstrated by the 40% reduction in apparent diffusion coefficient, a 70-80% reduction in cerebral blood flow was measured within the lesioned region. Transient hypoperfusion (40-50%) was also observed in the non-traumatized contralateral hemisphere, although there was no evidence of edema formation. After the initial cytotoxic edema, a clear evolution toward extracellular water accumulation was observed, demonstrated by an increase in apparent diffusion coefficient.