bluuebunny/crossref_metadata_2025_split huggingface dataset:
A critical appraisal of syrinx cavity shunting procedures
Authors: Batzdorf Ulrich , Klekamp Jörg , Johnson J. Patrick 
Published: June 2009

Object. This study was conducted to evaluate the results of shunting procedures for syringomyelia.
Methods. In a follow-up analysis of 42 patients in whom shunts were placed in syringomyelic cavities, the authors have demonstrated that 21 (50%) developed recurrent cyst expansion indicative of shunt failure. Problems were encountered in patients with syringomyelia resulting from hindbrain herniation, spinal trauma, or inflammatory processes. A low-pressure cerebrospinal fluid state occurred in two of 18 patients; infection was also rare (one of 18 patients), but both are potentially devastating complications of shunt procedures. Shunt obstruction, the most common problem, was encountered in 18 patients; spinal cord tethering, seen in three cases, may account for situations in which the patient gradually deteriorated neurologically, despite a functioning shunt.
Conclusions. Placement of all types of shunts (subarachnoid, syringoperitoneal, and syringopleural) may be followed by significant morbidity requiring one or more additional surgical procedures.
Functional image—guided surgery of intracranial tumors located in or near the sensorimotor cortex
Authors: Schulder Michael , Maldjian Joseph A. , Liu Wen-Ching , Holodny Andrei I. , Kalnin Andrew T. , Mun In Ki , Carmel Peter W. 
Published: June 2009

Object. The purpose of this study was to evaluate the efficacy of noninvasive preoperative functional imaging data used in an interactive fashion in the operating room. The authors describe a method of registering preoperative functional magnetic resonance (fMR) imaging localization of sensorimotor cortex with a frameless stereotactic surgical navigation device.
Methods. The day before surgery, patients underwent blood oxygen level—dependent fMR imaging while performing a finger-tapping motor paradigm. Immediately afterward an anatomical stereotactic MR image was acquired. Raw fMR imaging data were analyzed offline at a separate workstation, and the resulting functional maps were registered to a high-resolution anatomical scan. The fused functional—anatomical images were then downloaded onto a surgical navigation computer via an ethernet connection. At surgery, the brain was exposed in the standard fashion, and the sensorimotor cortex was identified by direct cortical stimulation, the use of somatosensory evoked potentials, or both. This localization was then compared with that predicted by the registered fMR study.
Thirteen procedures were performed in 12 patients. The mean registration error was 2.2 mm. The predicted location of motor and/or sensory cortex matched that found on intraoperative mapping in all 12 patients tested. Maximal tumor resection was accomplished in each case and no new permanent neurological deficits resulted.
Conclusions. Compared with conventional brain mapping techniques, fMR image—guided surgery may allow for smaller brain exposures, localization of the language cortex with the patient under general anesthesia, and the mapping of multiple functional sites. The scanning equipment used in this method may be more readily available than for other functional imaging techniques such as positron emission tomography or magnetoencephalography.
Effect of reduced cerebral perfusion pressure on cerebral blood flow following inhibition of nitric oxide synthesis
Authors: Rise Ingunn R. , Kirkeby Ole J. 
Published: June 2009

Object. The authors tested the hypothesis in a porcine model that inhibition of nitric oxide synthesis during reduced cerebral perfusion pressure (CPP) affected the relative cerebral blood flow (CBF) and the cerebrovascular resistance.
Methods. The CPP was reduced by inducing high cerebrospinal fluid pressure and hemorrhagic hypotension. With continuous blood and intracranial pressure monitoring, relative CPP was estimated using the laser Doppler flowmetry technique in nine pigs that received 40 mg/kg nitro-l-arginine methyl ester (l-NAME) and in nine control animals. The l-NAME caused a decrease in relative CBF (p < 0.01) and increases in cerebrovascular resistance (p < 0.01), blood pressure (p < 0.05), and CPP (p < 0.001). During high intracranial pressure there were no significant differences between the treated animals and the controls. After hemorrhage, there was no significant difference between the groups initially, but 30 minutes later the cerebrovascular resistance was decreased in the control group and increased in the l-NAME group relative to baseline (p < 0.05). Combined hemorrhage and high intracranial pressure increased the difference between the two groups with regard to cerebrovascular resistance (p < 0.05).
Conclusions. These results suggest that nitric oxide synthesis inhibition affects the autoregulatory response of the cerebral circulation after cardiovascular compensation has taken place. Nitric oxide synthesis inhibition enhanced the undesirable effects of high intracranial pressure during hypovolemia.
Effect of α-adrenergic blockade on the cerebrovascular response to increased intracranial pressure after hemorrhage
Authors: Rise Ingunn R. , Kirkeby Ole J. 
Published: June 2009

Object. In this study the authors tested the hypothesis that hemorrhagic hypotension and high intracranial pressure induce an increase in cerebrovascular resistance that is caused by sympathetic compensatory mechanisms and can be modified by α-adrenergic blockade.
Methods. Continuous measurements of cerebral blood flow were obtained using laser Doppler microprobes placed in the cerebral cortex in anesthetized pigs during induced hemorrhagic hypotension and high cerebrospinal fluid pressure. Eight pigs received 2 mg/kg phentolamine in 10 ml saline, and 13 pigs served as control animals. During high intracranial pressure occurring after blood loss, cerebral perfusion pressure (CPP) (p < 0.01) and cerebral blood flow (p < 0.01) decreased in both groups. Cerebrovascular resistance increased (p < 0.05) in the control group and decreased < 0.005) in the phentolamine-treated group. The cerebrovascular resistance was significantly lower in the phentolamine-treated group (p < 0.05) than in the control group. Cerebrovascular resistance increased at lower CPPs in the control group (linear correlation, r = 0.39, p < 0.01) and decreased with decreasing CPP in the phentolamine-treated group (linear correlation, r = 0.76, p < 0.001).
Conclusions. This study shows that the deleterious effects on cerebral hemodynamics induced by blood loss in combination with high intracranial pressure are inhibited by α-adrenergic blockade. This suggests that these responses are caused by α-adrenergically mediated cerebral vasoconstriction.
Rupture of a previously documented small asymptomatic intracranial aneurysm in a patient with autosomal dominant polycystic kidney disease
Authors: Schievink Wouter I. , Prendergast Virginia , Zabramski Joseph M. 
Published: June 2009

✓ Intracranial aneurysms are common extrarenal manifestations of autosomal dominant polycystic kidney disease (ADPKD). Although their natural history is not completely understood, small asymptomatic intracranial aneurysms in patients with ADPKD often are not treated but are followed with serial magnetic resonance (MR) angiography. The authors report the unique case of a patient with ADPKD who bled from a previously documented asymptomatic 3-mm intracranial aneurysm.
This 42-year-old man with ADPKD suffered a subarachnoid hemorrhage (SAH) from a 7-mm left pericallosal artery aneurysm. This aneurysm was clipped and the patient made an excellent recovery. An irregular asymptomatic 3-mm right middle cerebral artery (MCA) aneurysm had also been demonstrated on angiography. While the patient was considering elective surgery for the MCA aneurysm, he suffered a hemorrhage from this lesion 10 weeks after the initial SAH. The aneurysm was clipped and the patient made a satisfactory recovery (he was moderately disabled).
In this report the authors indicate that small asymptomatic intracranial aneurysms are not always innocuous in patients with ADPKD, and they suggest that treatment should be strongly considered for these lesions in this group of patients when there is a history of SAH or the aneurysm is irregular in appearance. Because MR angiography studies may not adequately define the configuration of small aneurysms and irregularity may easily be missed, conventional angiography is recommended for patients with ADPKD who are found to have an intracranial aneurysm on screening with MR angiography.
Factors affecting excitatory amino acid release following severe human head injury
Authors: Bullock Ross , Zauner Alois , Woodward John J. , Myseros John , Choi Sung C. , Ward John D. , Marmarou Anthony , Young Harold F. 
Published: June 2009

Object. Recent animal studies demonstrate that excitatory amino acids (EAAs) play a major role in neuronal damage after brain trauma and ischemia. However, the role of EAAs in patients who have suffered severe head injury is not understood. Excess quantities of glutamate in the extracellular space may lead to uncontrolled shifts of sodium, potassium, and calcium, disrupting ionic homeostasis, which may lead to severe cell swelling and cell death. The authors evaluated the role of EEAs in human traumatic brain injury.
Methods. In 80 consecutive severely head injured patients, a microdialysis probe was placed into the gray matter along with a ventriculostomy catheter or an intracranial pressure (ICP) monitor for 4 days. Levels of EAAs and structural amino acids were analyzed using high-performance liquid chromatography. Multifactorial analysis of the amino acid pattern was performed and its correlations with clinical parameters and outcome were tested. The levels of EAAs were increased up to 50 times normal in 30% of the patients and were significantly correlated to levels of structural amino acids both in each patient and across the whole group (p < 0.01). Secondary ischemic brain injury and focal contusions were most strongly associated with high EAA levels (27 ± 22 µmol/L). Sustained high ICP and poor outcome were significantly correlated to high levels of EAAs (glutamate > 20 µmol/L; p < 0.01).
Conclusions. The release of EAAs is closely linked to the release of structural amino acids and may thus reflect nonspecific development of membrane micropores, rather than presynaptic neuronal vesicular exocytosis. The magnitude of EAA release in patients with focal contusions and ischemic events may be sufficient to exacerbate neuronal damage, and these patients may be the best candidates for treatment with glutamate antagonists in the future.
Early changes in middle cerebral artery blood flow velocity after head injury
Authors: McQuire Joanne C. , Sutcliffe John C. , Coats Tim J. 
Published: June 2009

Object. This study was designed to investigate the incidence of early abnormalities in the cerebral circulation after head injury by relating the results of the initial computerized tomography (CT) scan with transcranial Doppler (TCD) ultrasound readings to see if the side of injury and the outcome can be predicted by using these modalities.
Methods. Transcranial Doppler ultrasound measurements were obtained in the emergency room in 22 head-injured patients less than 3 hours after injury. The middle cerebral artery (MCA) was insonated using a standard technique. The TCD measurements in each MCA were examined individually; of 39 measurements, 22 (56%) showed a low mean blood flow velocity, 27 (69%) demonstrated a high pulsatility index (PI), and 18 (46%) showed both abnormalities. The side of the cerebrovascular abnormality measured by TCD ultrasound did not appear to be an accurate predictor of the side of the injury as determined on the initial CT scan. Of 13 patients in whom either a space-occupying hematoma or signs of swelling were shown on the initial CT scan, 10 (77%) had an increased PI in one or both MCAs, which is an indication of high flow resistance.
Conclusions. Transcranial Doppler ultrasound examinations performed while patients are in the emergency room may have a role in determining treatment priorities, especially in those with multiple injuries.
Cerebral monitoring by means of oximetry and somatosensory evoked potentials during carotid endarterectomy
Authors: Cho Hun , Nemoto Edwin M. , Yonas Howard , Balzer Jeffrey , Sclabassi Robert J. 
Published: June 2009

Object. Cerebral ischemia that occurs during carotid endarterectomy is commonly monitored by means of somatosensory evoked potentials (SSEPs) and electroencephalography (EEG). The authors conducted this study to determine whether cerebral ischemia could also be reliably detected by cerebral oximetry.
Methods. Twenty-nine patients who underwent carotid endarterectomy were monitored by means of SSEPs, EEG, and cerebral oximetry with a model NIRO500 (20 patients) or INVOS3100A (nine patients) oximeter. Changes in amplitude of SSEPs were graded as follows: 0, no change; 1, decrease of less than 50%; 2, decrease of greater than 50%; and 3, 100% decrease. As measured with the NIRO500 oximeter, closing the common caro-tid artery decreased mean oxyhemoglobin levels twice as much (p < 0.005) in the group with SSEPs of 1 to 3 (−13.11 ± 5.59 µM [mean ± standard deviation], 12 patients) as in the group with SSEPs of 0 (−6.22 ± 5.59 µM, eight patients). The rise in deoxyhemoglobin was also greater (p < 0.05). Two of nine patients monitored with the INVOS3100A oximeter had SSEPs of 1 and 3, and their regional saturation of oxygen (rSO2) values fell by −11.50 and −11.51, respectively. In the remaining seven patients with SSEPs of 0, the rSO2 ranged between −2.00 and −6.10 with no overlap with the group with SSEPs of 1 to 3. The increase in oxyhemoglobin monitored using the NIRO500 oximeter and rSO2 monitored using the INVOS3100A machine after opening the external carotid artery was less than that seen after opening the internal carotid artery. Both types of oximeters could detect cerebral ischemia but whereas false negatives occurred with the NIRO500, none was observed with the INVOS3100A. Extracranial contamination was also four times less frequent with the INVOS3100A than with the NIRO500 monitor.
Conclusions. The results indicate that at least as measured with the INVOS3100A instrument, a decrease in rSO2 of −10 or more or a decrease below an rSO2 of 50 is indicative of cerebral ischemia of sufficient severity to decrease the amplitude of SSEPs.
Metastatic brain tumors with dural extension
Authors: Rumana Christopher S. , Hess Kenneth R. , Shi Wei Ming , Sawaya Raymond 
Published: June 2009

Object.Twenty-two patients who had solitary metastatic brain tumors with dural extension were treated surgically over a 3-year period. Their cases were reviewed to characterize these lesions and to compare the patients with a similar cohort in which there was no dural involvement.Methods.The median age of the patients was 58 years (range 11–68 years) and the male/female ratio was 12:10. The median preoperative Karnofsky Performance Scale (KPS) score in the group was 90 (range 70–100). The most common histological diagnoses seen in these patients included breast cancer, adenocarcinoma and squamous cell carcinoma of the lung, and renal cell carcinoma. All patients underwent gross-total resection of the tumor and 86% received radiation therapy. The median patient survival time was 11 months, with a median time to recurrent intracranial disease of 19 months. Survival was related to the histological diagnosis. Recurrent disease occurred in 41% of cases. Leptomeningeal disease occurred in three patients (14%). The frequency and time course of development of recurrent disease was not affected by dural resection nor was survival.These results for patients having metastatic brain tumors with dural extension were compared with those for a cohort of 26 patients in which there were similar histological diagnosis, age, gender, and preoperative KPS score were distributed similarly but in which each patient had a single subcortical metastatic lesion. Those patients had a median survival of 10 months and the median time to recurrence was not reached. Leptomeningeal disease occurred in one patient (4%).Conclusions.To the authors' knowledge, this is the first reported series of patients with metastatic brain tumors with dural extension. Patients with this disease may be more likely to develop recurrences along the dura and leptomeningeal disease, but the overall survival time in these patients is not different from those patients with intraparenchymal lesions.
Changing central nervous system control following intercostal nerve transfer
Authors: Malessy Martijn J. A. , Thomeer Ralph T. W. M. , Dijk J. Gert van 
Published: June 2009

Object.The goal of this study was to find which central nervous system (CNS) pathways are involved in volitional control over reinnervated biceps or pectoral muscles.Methods.Intercostal nerves (ICNs) were coapted to the musculocutaneous nerve (MCN) or the medial pectoral nerve (MPN) in 23 patients with root avulsions of the brachial plexus to restore biceps or pectoral muscle function. The facilitatory effects of respiration and voluntary contraction on cortical motor-evoked potentials of biceps or pectoral muscles were used to study CNS control over the reinnervated muscles. The time course of the facilitatory effect of respiration and voluntary contraction differed significantly. In the end stage of nerve regeneration, the facilitatory effect of voluntary contraction was significantly larger than that of respiration, indicating that the CNS control network over the muscle comes to resemble that of the recipient nerve (MCN or MPN) rather than that of the donor nerve (ICN).Conclusions.The strengthening of previously subthreshold synaptic connections in a CNS network connecting ICN to MCN or MPN neurons may underlie changing excitability.
Fatal cyst formation after fetal mesencephalic allograft transplant for Parkinson's disease
Authors: Mamelak Adam N. , Eggerding Faye A. , Oh Daniel S. , Wilson Erika , Davis Richard L. , Spitzer Richard , Hay Jefferey A. , Caton William L. 
Published: June 2009

Object. In recent years, fetal mesencephalic tissue transplant for the treatment of Parkinson's disease (PD) has been demonstrated to hold promise, but potential complications related to growth of allograft tissue have not been well described. This report explores the development and possible causation of a fatal cyst arising from a fetal transplant in the brain.
Methods. The authors report the case of a 52-year-old woman who underwent bilateral putamenal fetal mesencephalic allograft transplant for PD at another hospital. Twenty-three months later she presented to the authors' institution in a coma. Admission computerized tomography and magnetic resonance (MR) studies revealed a contrast-enhancing mural nodule and associated large cyst arising from the left putamen and causing brainstem compression. Despite surgical decompression of the cyst, the patient did not regain consciousness. Biopsy and autopsy specimens were obtained, along with an analysis of the cyst fluid. Genotyping of the nodule and the patient's peripheral lymphocytes by using polymerase chain reaction—based microsatellite analysis was also performed. Biopsy samples and autopsy histopathological studies showed inflammatory cells, hemosiderin-laden macrophages, and astrocytosis. Scattered neurons and multiple rests of choroid plexus were also noted. The cyst had a thin wall and contained liquid that was identical in composition to cerebrospinal fluid (CSF). Genotyping demonstrated the presence of alleles in the nodule DNA that were not present in lymphocytic DNA, indicating that the nodule contained allograft tissue.
Conclusions. The authors hypothesize that the choroid plexus tissue contained in the allograft resulted in CSF production and cyst formation at the transplant site, ultimately leading to the patient's herniation syndrome. The clinical history and large size of the mural nodule indicate slow growth of this allograft site and cyst over time. This case demonstrates that unusual patterns of tissue growth can occur in the brain after fetal tissue transplant and emphasizes the need for long-term monitoring of posttransplant patients by means of MR imaging. Cell sorting should be considered to ensure transplant of pure neuronal and astroglial populations.
Early magnetic resonance imaging of brainstem lesions after severe head injury
Authors: Firsching Raimund , Woischneck Dieter , Diedrich Michael , Klein Susan , Rückert Andreas , Wittig Holger , Döhring Wilfried 
Published: June 2009

Object. The availability of magnetic resonance (MR) imaging data obtained in comatose patients after head injury is scarce, because MR imaging is somewhat cumbersome to perform in patients requiring ventilation and because, in the first hours after injury, its relevance is clearly inferior to computerized tomography (CT) scanning. The authors assessed the value of MR imaging in the early postinjury period.
Methods. In this prospective study MR imaging was performed in 61 consecutive patients within 7 days after they suffered a severe head injury. An initial CT scan had already been obtained. To understand the clinical significance of the lesions whose morphological appearance was identified with MR imaging, brainstem function was assessed by registration of somatosensory and auditory evoked potentials.
Brainstem lesions were visualized in 39 patients (64%). Bilateral pontine lesions proved to be 100% fatal and nonbrainstem lesions carried a mortality rate of 9%.
In singular cases circumstances allowed for a clear clinical distinction between primary and secondary brainstem lesions. On MR imaging all lesions were hyper- and hypointense after intervals longer than 2 days. Within shorter intervals (< 2 days) after the injury, primary lesions appeared isointense on MR imaging. In one secondary brainstem lesion there were no traces of blood.
Conclusions. Because mean intracranial pressure (ICP) levels in patients without brainstem lesions were similar to those in patients with brainstem lesions, the authors conclude that it was not mainly increased ICP that accounted for the high mortality rates in patients with brainstem lesions.
The authors also conclude that brainstem lesions are more frequently found in severe head injury than previously reported in studies based on neuropathological or CT scanning data. Early MR imaging after head injury has a higher predictive value than CT scanning.