bluuebunny/crossref_metadata_2025_split huggingface dataset:
High extracellular potassium and its correlates after severe head injury: relationship to high intracranial pressure
Authors: Reinert Michael , Khaldi Ahmad , Zauner Alois , Doppenberg Egon , Choi Sung , Bullock Ross 
Published: January 2008

Disturbed ionic and neurotransmitter homeostasis are now recognized to be probably the most important mechanisms contributing to the development of secondary brain swelling after traumatic brian injury (TBI). Evidence obtained from animal models indicates that posttraumatic neuronal excitation via excitatory amino acids leads to an increase in extracellular potassium, probably due to ion channel activation. The purpose of this study was therefore to measure dialysate potassium in severely head injured patients and to correlate these results with intracranial pressure (ICP), outcome, and also with the levels of dialysate glutamate, lactate, and cerebral blood flow (CBF) so as to determine the role of ischemia in this posttraumatic ionic dysfunction.
Eighty-five patients with severe TBI (Glasgow Coma Scale score < 8) were treated according to an intensive ICP management-focused protocol. All patients underwent intracerebral microdialyis. Dialysate potassium levels were analyzed by flame photometry, as were dialysate glutamate and dialysate lactate levels, which were measured using high-performance liquid chromatography and an enzyme-linked amperometric method in 72 and 84 patients respectively. Cerebral blood flow studies (stable Xenon–computerized tomography scanning) were performed in 59 patients.
In approximately 20% of the patients, potassium values were increased (dialysate potassium > 1.8 mmol). Mean dialysate potassium (> 2 mmol) was associated with ICP above 30 mm Hg and fatal outcome. Dialysate potassium correlated positively with dialysate glutamate (p < 0.0001) and lactate levels (p < 0.0001). Dialysate potassium was significantly inversely correlated with reduced CBF (p = 0.019).
Dialysate potassium was increased after TBI in 20% of measurements. High levels of dialysate potassium were associated with increased ICP and poor outcome. The simultaneous increase of potassium, together with dialysate glutamate and lactate, supports the hypothesis that glutamate induces ionic flux and consequently increases ICP due to astrocytic swelling. Reduced CBF was also significantly correlated with increased levels of dialysate potassium. This may be due to either cell swelling or altered potassium reactivity in cerebral blood vessels after trauma.
Combined magnetic resonance imaging– and positron emission tomography–guided stereotactic biopsy in brainstem mass lesions: diagnostic yield in a series of 30 patients
Authors: Massager Nicolas , David Philippe , Goldman Serge , Pirotte Benoît , Wikler David , Salmon Isabelle , Nagy Nathalie , Brotchi Jacques , Levivier Marc 
Published: January 2008

In the management of brainstem lesions, the place of stereotactic biopsy sampling remains debatable. The authors compared the results of magnetic resonance (MR) imaging, positron emission tomography (PET), and histological findings obtained in 30 patients who underwent an MR image– and PET-guided stereotactic biopsy procedure for a brainstem mass lesion.
Between July 1991 and December 1998, 30 patients harboring a brainstem mass lesion underwent a stereotactic procedure in which combined MR imaging and PET guidance was used. Positron emission tomography scanning was performed using [18F]-fluorodeoxyglucose in 16 patients, methionine in two patients, and with both tracers in 12 patients. Definite diagnosis was established on histological examination of the biopsy samples. Interpretation of MR imaging findings only or PET findings only were in agreement with the histological diagnosis in 63% and 73% of cases, respectively. Magnetic resonance imaging and PET findings were concordant in 19 of the 30 cases; in those cases, imaging data correlated with histological findings in 79%. In seven patients who underwent one PET-defined and one MR imaging–defined trajectory, at histological examination the PET-guided samples were more representative of the tumor's nature and grade than the MR imaging–guided samples in four cases (57%). In 18 patients PET scanning was used to define a biopsy target and provided a diagnostic yield in 100% of the cases.
Although the use of combined PET and MR imaging improves radiological interpretation of a mass lesion in the brainstem, it does not accurately replace histological diagnosis that is provided by a stereotactically obtained biopsy sample. Combined information provided by MR imaging and PET in stereotactic conditions improves the accuracy of targeting and the diagnostic yield of the stereotactically biopsy sample; an MR imaging– and PET-guided stereotactic biopsy procedure is a safe and efficient modality for the management of mass lesions of the brainstem.
Use of fluorodeoxyglucose–positron emission tomography for the differentiation of cerebral lesions in patients with acquired immune deficiency syndrome
Authors: Menendez Jose A. , Lilien David L , Nanda Anil , Polin Richard S. 
Published: January 2008

Intracranial mass lesions comprise approximately half of all acquired immune deficiency syndrome (AIDS)–related neurological complications. Although toxoplasmosis and lymphoma are the most common causes of these lesions, diagnosis and treatment can be delayed because computerized tomography and magnetic resonance imaging studies cannot accurately differentiate between them.
The authors retrospectively studied nine patients with AIDS in whom, after a 6-hour fast, [18F]-fluorodeoxyglucose (FDG)–positron emission tomography (PET) scanning demonstrated intracranial mass lesions. The FDG uptake within each lesion was classified as either increased or not increased. In six patients there was no increase in FDG uptake, which suggested a diagnosis of toxoplasmosis, and lymphoma was suggested in two patients in whom increased FDG uptake was demonstrated. In a patient with two lesions, one lesion was shown to have increased FDG uptake whereas the other was shown to have no increased FDG uptake. All patients in whom a diagnosis of toxoplasmosis was made were started on antimicrobial therapy. Two patients died of other AIDS-related complications before repeated neuroimaging could be performed to assess treatment response, one patient refused to undergo further treatment or follow up, and two patients responded well to treatment. One patient with toxoplasmosis did not respond to the drugs. Analysis of a biopsy sample of the lesion confirmed the diagnosis; however, the patient died shortly thereafter. The two patients with FDG-PET–diagnosed lymphoma began corticosteroid therapy and improved considerably. In the patient in whom PET demonstrated two different FDG uptakes, a biopsy sample was obtained that confirmed the diagnosis of lymphoma; this patient was started on corticosteroid therapy and improved. A safe and reliable diagnostic tool, FDG-PET scanning can be used to differentiate causes of human immunodeficiency virus-related intracranial mass lesions. When available, this diagnostic study should be conducted before initiating empirical treatment or obtaining a stereotactically guided brain biopsy sample.
Functional brain mapping using positron emission tomography scanning in preoperative neurosurgical planning for pediatric brain tumors
Authors: Kaplan Allen M. , Bandy Daniel J. , Manwaring Kim H. , Chen Kewei , Lawson Michael A. , Moss S. David , Duncan Johnny D. , Wodrich David L. , Schnur James A. , Reiman Eric M. 
Published: January 2008

Object
The purpose of this report is to demonstrate the value of functional brain mapping using the positron emission tomography (PET) method for preoperative neurosurgical planning in children with brain tumors. Brain maps were used to characterize the relationship between potentially resectable tumors and functionally eloquent brain areas.

Methods
Five children, ranging in age from 3 to 13 years, with hemispheric brain tumors adjacent to eloquent cortex were studied. Magnetic resonance (MR) imaging was used to identify the brain tumors; PET imaging after injection of [18F]fluorodeoxyglucose (FDG), [11C]l-methionine (CMET), or a combination of the two was performed to grade the tumors; and a [15O] H2O uptake study was used to characterize the anatomical relationships of the tumors to functional cortex. The cortical activation maps were obtained during control periods and during behavioral tasks and were used to document motor, visual, and speech and language organizational areas. Wada tests were performed in two patients. Language and speech activation was concordant with the results of Wada testing.

Conclusions
Functional brain mapping using PET scans and coregistered MR images provided the neurosurgeon with precise definitions of structural and functional cortical areas; this altered surgical management in some cases and/or was used to predict outcome. The combination of PET imaging with FDG and/or CMET and measurements of [15O] water uptake was useful in characterizing and grading tumors and instrumental in achieving effective neurosurgical planning. Postoperative results in the five cases suggest that preoperative functional brain mapping has the potential to improve outcome by defining a surgical plan to maximize resection and minimize the risk of neurological sequelae.
Classification of syringomyelia
Authors: Milhorat Thomas H. 
Published: January 2008

Syringomyelia poses special challenges for the clinician because of its complex symptomatology, uncertain pathogenesis, and multiple options of treatment. The purpose of this study was to classify intramedullary cavities according to their most salient pathological and clinical features.
Pathological findings obtained in 175 individuals with tubular cavitations of the spinal cord were correlated with clinical and magnetic resonance (MR) imaging findings in a database of 927 patients. A classification system was developed in which the morbid anatomy, cause, and pathogenesis of these lesions are emphasized.
The use of a disease-based classification of syringomyelia facilitates diagnosis and the interpretation of MR imaging findings and provides a guide to treatment.
Toward a rational treatment of Chiari I malformation and syringomyelia
Authors: Ellenbogen Richard G. , Armonda Rocco A. , Shaw Dennis W. W. , Winn H. Richard 
Published: January 2008

In patients with Chiari I malformation with and without associated syringomyelia, aberrant cerebrospinal fluid (CSF) dynamics and a spectrum of posterior fossa pathological findings are demonstrated. In this study, the authors test the validity of using prospective cardiac-gated phase-contrast cine-mode magnetic resonance (MR) imaging to define the malformation, delineate its pathophysiology, and assist in implementing a rational treatment plan.
Eighty-five cases were prospectively analyzed using cine MR imaging. Sixty-five patients, adults and children, with symptomatic Chiari malformation, with and without syringomyelia, were surgically treated from 1990 to 1999. All patients underwent pre- and postoperative cine MR evaluation. Ten patients were treated after a previous surgical procedure had failed. To establish CSF flow characteristics and normative CSF profiles, 20 healthy volunteers were examined.
Compared with normal volunteers, in Chiari I malformation patients with and without syringomyelia, uniformly abnormal craniocervical junction CSF flow profiles were revealed. After intradural exploration, nearly all patients with Chiari I malformation experienced clinical improvement and CSF flow profiles, paralleling those of normal volunteers, were shown. In all patients in whom treatment had failed, abnormal preoperative CSF flow profiles, which correlated with suspected physiological abnormalities and the pathological findings noted at reoperation, were demonstrated.
Symptomatic Chiari I malformation is a dynamic process characterized by the impaction of the hindbrain in an abnormal posterior fossa. This compression obstructs the normal venting of CSF in and out of the craniocervical sub-arachnoid space, throughout the cardiac cycle. Therefore, decompression or enlargement of the posterior fossa to establish normal CSF pathways should be the primary goal of surgical intervention. Aberrant CSF flow appears to be only one aspect of the pathological condition found in patients with Chiari I malformation. Arachnoid scarring in the posterior fossa and selective vulnerability of the spinal cord may also be factors in the pathogenesis and maintenance of associated syringomyelia. Phase-contrast cine MR imaging is a useful tool in defining physiological and anatomical problems in patients with Chiari I and syringomyelia, and it can help guide an appropriate primary or salvage surgical therapy.
Treatment of posttraumatic syringomyelia with extradural decompressive surgery
Authors: Holly Langston T. , Johnson J. Patrick , Masciopinto Jeffrey E. , Batzdorf Ulrich 
Published: January 2008

The authors review the management of five patients with posttraumatic syringomyelia (PTS) associated with an uncorrected spinal deformity. Patients with evidence of progressive neurological deterioration underwent ventral spinal decompressive surgery.
The mean patient age at the time of injury was 39 years, and the time between injury and the diagnosis of PTS ranged from 2 to 22 years. Mechanisms of injury consisted of fracture/subluxations in three patients and burst fractures in two. All patients experienced delayed neurological deterioration consistent with PTS. Magnetic resonance imaging revealed ventral deformities, and the spinal canal stenosis ranged from 20 to 50% (mean 39%). All patients underwent ventral epidural spinal decompressive surgery to correct the bone deformity and restore the spinal canal.
The mean follow-up period was 38 months. The decompressive intervention was initially successful in treating the neurological deterioration in all patients. Symptoms resolved completely in four patients, and the other experienced neurological improvement. Postoperative magnetic resonance imaging revealed a reduction in the size of syrinx cavity in the patients whose symptoms resolved and no change in the remaining patient. Two patients required a subsequent second-stage posterior intradural exploration and duraplasty for recurrence of symptoms and/or syrinx.
Posttraumatic spinal deformity may cause spinal canal stenosis and alter subarachnoid cerebrospinal fluid (CSF) flow in certain patients. Ventral epidural spinal decompressive surgery may result in neurological improvement and a reduction of the syrinx cavity, avoiding the need for placement of a shunt or other intradural procedures. However, some patients will also require reconstruction of the posterior subarachnoid space with duraplasty if the ventral decompressive procedure achieves only partial restoration of the subarachnoid CSF flow.
A light and electron microscopic study of ectopic tendon and ligament formation induced by bone morphogenetic protein–13 adenoviral gene therapy
Authors: Helm Gregory A. , Li Jin Zhong , Alden Tord D. , Hudson Sarah A. , Beres Elisa J. , Cunningham Mary , Mikkelsen Mark M. , Pittman Debra D. , Kerns Kelvin M. , Kallmes David F. 
Published: January 2008

Object
Bone morphogenetic proteins (BMPs) are involved in the growth and development of many tissues, but it is their role in skeletal development and their unique ability to induce ectopic and orthotopic osteogenesis that has attracted the greatest interest. Expression of the BMP-13 gene has been shown to be predominantly localized to hypertrophic chondrocytes in regions of endochondral bone formation during development, as well as in mature articular cartilage in the adult. In addition, the application of BMP-13 on a collagen carrier induces neotendon/ligament formation when delivered subcutaneously or intramuscularly in rodents. The aim of the present study was to determine the histological and ultrastructural changes that occur after the intramuscular injection of a first-generation BMP-13 adenoviral vector.

Methods
Athymic nude rats were injected with 3.75 × 1010 plaque-forming unit adenovirus (Ad)-BMP-13 or Ad-β-galactosidase in the thigh musculature, and the regions examined using light and electron microscopy at various time points between 2 and 100 days postinjection. As early as 2 days after injection of Ad-BMP-13, progenitor cells were observed infiltrating between the transduced muscle fibers. These cells subsequently proliferated, differentiated, and secreted large amounts of collagenous extracellular matrix. By 100 days postinjection, the induced tissue had the histological and ultrastructural appearance of neotendon/ligament, which was clearly demarcated from the surrounding muscle. Small foci of bone and fibrocartilage were also seen within the induced tissue. A short-term bromodeoxyuri-dine study also demonstrated rapid mesenchymal cell proliferation at the Ad-BMP-13 injection site as early as 48 hours postinjection.

Conclusions
The results of this study suggest that in the future the use of the BMP-13 gene may have therapeutic utility for the healing of tendon and ligament tears and avulsion injuries.
Evaluation of big endothelin–1 concentrations in serum and ventricular cerebrospinal fluid after early surgical compared with nonsurgical management of ruptured intracranial aneurysms
Authors: Gruber Andreas , Roessler Karl , Georgopoulos Apostolos , Mißbichler Albert , Bonelli Raphael , Richling Bernd , Bavinzski Gerhard , Czech Thomas 
Published: January 2008

Object
Whereas the removal of subarachnoid blood is possible during early-stage aneurysm surgery, this cannot be achieved in aneurysms treated by endovascular means. The levels of potential spasmogens in the cerebrospinal fluid (CSF) in patients receiving endovascular treatment might therefore be higher, with the potential for more severe post–subarachnoid hemorrhage (SAH) vasospasm.

Methods
Serum and CSF concentrations of big endothelin (ET)–1 were serially measured in patients with SAH receiving one of the following treatments: 1) early (within 72 hours of SAH) aneurysm surgical treatment (15 patients), 2) early endovascular treatment (17 patients), or 3) no intervention in the acute phase (12 patients). In patients suffering delayed infarctions higher levels of big ET–1 CSF were demonstrated than in those without infarctions (p = 0.01). In patients in whom surgery was performed in the acute phase lower big ET–1 CSF concentrations were demonstrated than in those who received embolization treatment or no treatment (p = 0.02). Subgroup analysis demonstrated that in patients receiving early endovascular treatment, higher big ET–1 CSF concentrations were revealed than in those undergoing early aneurysm surgery; this was true for patients with (microsurgery-treated, 1.84 ± 0.83 pg/ml; and embolization-treated 2.19 & plusmn; 0.54 pg/ml) and without (microsurgery-treated 1.76 & plusmn; 0.61 pg/ml; and embolization-treated 2.01 ± 0.48 pg/ml) delayed infarctions.

Conclusions
Among patients with SAH who received treatment during the acute phase, those undergoing early aneurysm surgery were shown to have lower big ET–1 CSF levels than those receiving embolization and no treatment (that is, the nonsurgical treatment groups). The clinical significance of this finding remains to be established in future clinical trials, because in the present study the trend toward lower levels of big ET–1 CSF in the microsurgically treated group was not paralleled by a lower delayed stroke rate or an improvement in neurological outcome.
Introduction to odontoid fractures: controversies in the management of odontoid fractures
Authors: Przybylski Gregory J. 
Published: January 2008

Although odontoid fractures were first classified more than 25 years ago,5 the management of these fractures remains controversial. Whereas the nonoperative management with external immobilization devices often leads to successful healing, certain fracture features and patient characteristics have been associated with an increased risk of bone nonunion.6,17 Recent technological advances in cervical spine instrumentation techniques have provided additional options for the management of these common fractures.1,12,13,24,27,28 However, an absence of rigorous studies in which the investigators compare management methods may contribute to the varying methods used by spine surgeons when approaching similar injuries.
In this issue of Neurosurgical Focus, various aspects of the management of odontoid fractures are examined. In an evidence-based analysis of methods for treating odontoid fractures the authors examine the best available published data to determine the level of scientific data supporting the use of various treatment options.3 In epidemiological studies the investigators examine factors contributing to the unusual incidence of spinal cord injury with odontoid fractures as well as the unique considerations that may be attendant on the management of posteriorly displaced fractures. In two other studies the authors discuss the application of specific surgical techniques in treating odontoid fractures, whereas in an additional two reports the authors evaluate the difficulties in managing elderly patients with these injuries. Finally, the use of newer osteoinductive agents is examined as a potential adjunct in the surgical management of bony defects in the dens.
Surgical treatment of complex traumatic frontobasal lesions: personal experience in 74 patients
Authors: Piek Jürgen 
Published: January 2008

Object
The author's personal series included 148 patients who sustained traumatic frontobasal injuries and were treated between 1986 and 1999. Included in this study are 74 of 148 patients with acute injuries and complex fronto-basal lesions involving the frontal sinus, the cribriform/ethmoid roof complex, one or both orbital roofs, and the planum sphenoidale.

Methods
Surgery was delayed for up to 4 weeks postinjury in most patients (67 cases), whereas 17 with space-occupying hematomas and perforating injuries required early surgery. In 30 patients additional surgery was required to treat maxillofacial fractures, which was performed as a one-stage procedure together with the neurosurgical operation. The author performed a standard bifrontal craniotomy in which an intradural or combined intradural–extradural approach was used in all cases.
Four patients developed ascending meningitis in the preoperative period. As a result of surgical treatment one patient died, another two patients suffered from permanent defects, and three suffered from transitory neurological worsening. In two patients recurrence of a cerebrospinal fluid fistula occurred within a 3-month period posttreatment but was successfully obliterated during reoperation.
In the author's experience the intradural approach is comparable in terms of the morbidity, mortality, and success rates with extracranial approaches; additionally the intradural approach provides full visualization of the intracranial lesion. Useful olfactory nerve function can only be preserved if both olfactory nerves are left intact and not crushed during initial injury; this occurred in only five patients in this series.

Conclusions
If possible, surgical treatment of more complex lesions should be delayed until the 2nd or 3rd week following traumatic injury. With antibiotic prophylaxis the risk that ascending meningitis will occur prior to surgery is low. If the patient is systemically stable and brain swelling has resolved, even extensive one-stage neurosurgical/ maxillofacial procedures are well tolerated.