bluuebunny/crossref_metadata_2025_split huggingface dataset:
Motor-evoked potential monitoring for intramedullary spinal cord tumor surgery: correlation of clinical and neurophysiological data in a series of 100 consecutive procedures
Authors: Kothbauer Karl F. , Deletis Vedran , Epstein Fred J. 
Published: January 2008

Resection of intramedullary spinal cord tumors carries a high risk for surgical damage to the motor pathways. This surgery is therefore optimal for testing the performance of intraoperative motor evoked potential (MEP) monitoring. This report attempts to provide evidence for the accurate representation of patients' pre- and postoperative motor status by combined epidural and muscle MEP monitoring during intramedullary surgery.
The authors used transcranial electrical motor cortex stimulation to elicit MEPs, which were recorded from the spinal cord (with an epidural electrode) and from limb target muscles (thenar, anterior tibial) with needle electrodes. The amplitude of the epidural MEPs and the presence or absence of muscle MEPs were the parameters for MEP interpretation. A retrospective analysis was performed on data from the resection of 100 consecutive intramedullary tumors and MEP data were compared with the pre- and postoperative motor status.
Intraoperative monitoring was feasible in all patients without severe preoperative motor deficits. Preoperatively paraplegic patients had no recordable MEPs. The sensitivity of muscle MEPs to detect postoperative motor deficits was 100% and its specificity was 91%. There was no instance in which a patient with stable MEPs developed a motor deficit postoperatively. Intraoperative MEPs adequately represented the motor status of patients undergoing surgery for intramedullary tumors. Because deterioration of the motor status was transient in all cases, it can be considered that impairment of the functional integrity of the motor pathways was detected before permanent deficits occurred.
Surgical anatomy of the juxtadural ring area
Authors: Oikawa Susumu , Kyoshima Kazuhiko , Kobayashi Shigeaki 
Published: January 2008

Object
The authors report on the surgical anatomy of the juxtadural ring area of the internal carotid artery to add to the information available about this important structure.

Methods
Twenty sides of cadaver specimens were used in this study. The plane of the dural ring was found to incline in the posteromedial direction. Medial inclination was measured at 21.8š on average against the horizontal line in the anteroposterior view on radiographic studies. Posterior inclination was measured at 20.3š against the planum sphenoidale in the lateral projection, and the medial edge of the dural ring was located 0.4 mm above the tuberculum sellae in the same projection. The lateral edge of the tuberculum sellae was located 1.4 mm below the superior border of the anterior clinoid process. The carotid cave was situated at the medial or posteromedial aspect of the dural ring; however, two of the 20 specimens showed no cave formation. The carotid cave contained the subarachnoid space in 13 sides, the arachnoid membrane only in three sides, and the extraarachnoid space in two sides. The authors propose that the marker of the medial side of the dural ring, which is more proximal than the lateral, is the tuberculum sellae in the lateral view on radiographic studies. In the medial aspect of the dural ring the intradural space can be situated below the level of the tuberculum sellae because of the existence of the carotid cave.

Conclusions
The authors found that an aneurysm arising from the medial side of the juxtadural ring area even below the tuberculum sellae is a potential cause of subarachnoid hemorrhage.
Clinical response of O6-methylguanine-DNA methyltransferase levels to 1,3-(2-chloroethyl)-1-nitrosourea chemotherapy in glioma patients
Authors: Chen Zhong-Ping , Yarosh Daniel , Garcia Yesenia , Tampieri Donatella , Mohr Gérard , Langleben Adrian , Panasci Lawrence C. 
Published: January 2008

Adjuvant nitrosourea chemotherapy fails to prolong patient survival significantly as many tumors demonstrate resistance to these drugs. It has been documented in cell lines that O6-methylguanine-DNA methyltransferase (MGMT) plays an important role in chloroethylnitrosourea (CENU) drug resistance.
The authors evaluated MGMT expression in 22 glioma specimens by using an immunofluorescence assay and compared the results with clinical response of the patients to CENU-based chemotherapy.
The patients were treated with CENU after evidence of progressive disease following surgery and radiotherapy. Eight tumor samples had no detectable MGMT, whereas other samples had from 9989 to 982,401 molecules/nucleus. In one group (12 patients), the tumor decreased in size or was stable (effective group), whereas in the other group (10 patients), the tumor demonstrated continuous growth during chemotherapy (progressive group). The median time to progression (TTP) was 6.7 months with a median survival of 13 months. The Mer− patients (MGMT < 60,000 molecules/nucleus) appeared to have more chance of stable disease or response to CENU therapy than the Mer+ patients (MGMT > 60,000 molecules/nucleus) (chi-square = 4.791, p = 0.0286). In patients with glioblastomas multiforme (GBMs), the TTP of Mer+ patients was shorter than that of Mer− patients (t = 2.04, p = 0.049). As a corollary, the MGMT levels were significantly higher in GBM tumors from the progressive group than those from the effective group (t = -2.26, p = 0.029). The TTP and survival time in the effective GBM group were also longer than those in the progressive GBM group. However, there was no significant correlation between MGMT levels and either the survival time (r = 0.04, p = 0.8595) or TTP (r = 0.107, p = 0.6444).
Results from this study suggested that MGMT positivity is indicative of more aggressive disease that progresses more rapidly when exposed to CENU therapy. However, MGMT-negative tumors are not always sensitive to CENU agents, suggesting that other factors may also be important.
Pathogenesis of intracranial germ cell tumors reconsidered
Authors: Sano Keiji 
Published: January 2008

The author studied 153 cases of intracranial germ cell tumors (GCTs) through 1994, 62.7% of which showed monotypic histological patterns and 37.3% of which were shown to be mixed tumors. All of these cases, except for six patients who died soon after admission and underwent autopsy, underwent surgery followed by radio- and/or chemotherapy. All patients with choriocarcinoma died within 2 years. Patients with yolk sac tumor (endodermal sinus tumor) and embryonal carcinoma also had poor outcomes. Patients with mature teratoma had 5- and 10-year survival rates of 92.9% each. Patients with immature teratoma and malignant teratoma had a 5- and 10-year survival rate of 70.7% each. Patients with germinoma had a 5-year survival rate of 95.4% and a 10-year survival rate of 92.7%. These results may bring into question the validity of the germ cell theory, because germinoma, which should be the most undifferentiated according to the theory, was the most benign and choriocarcinoma and yolk sac tumor (endodermal sinus tumor), which should be the most differentiated, were the most malignant according to results obtained during follow-up study.
Therefore, GCTs other than germinoma may not originate from one single type of cell (primordial germ cells). The embryonic cells of various stages of embryogenesis may perhaps be misplaced in the bilaminar embryonic disc at the time of the primitive streak formation, becoming involved in the stream of lateral mesoderm and carried to the future cranial area to become incorrectly enfolded into the brain at the time of the neural tube formation. The authors propound the following law: tumors composed of cells resembling the cells that appear in the earlier stages of embryogenesis (ontogenesis) are more malignant than those composed of cells resembling the cells that appear in the later stages of embryogenesis.
Immunohistochemical analysis of p53 and p21WAF1/Cip1 expression in primary intracranial germ cell tumors
Authors: Nishikawa Ryo , Matsutani Masao 
Published: January 2008

Primary intracranial germ cell tumors (GCTs) comprise 3.1% of all brain tumors and 13.6% of those in patients younger than 15 years of age in Japan. They are classified into five basic histological types: germinoma, teratoma, choriocarcinoma, yolk sac tumor, and embryonal carcinoma; or into mixed tumor types when they consist of two or more components. Radiation therapy with or without chemotherapy has proven effective in the treatment of germinoma, whereas there is a poor prognosis for choriocarcinoma, yolk sac tumor, embryonal carcinoma, and mixed tumors having components of the group of malignant intracranial GCTs. The underlying mechanisms for such different responses to radio- and chemotherapies of intracranial GCTs remain unknown.
In this study, the authors analyzed the expression of p53 and p21WAF1/Cip1 proteins by immunohistochemical analysis in 35 intracranial GCTs. Expression of p53 protein was observed in 33 (94%) of 35 intracranial GCTs. Expression of p21WAF1/Cip1 was detected in seven (20%) of 35 intracranial GCTs. None of the 15 germinomas was immunoreactive for p21WAF1/Cip1 protein, whereas in a group of malignant intracranial GCTs, four (80%) of five cases showed immunoreactivity for p21WAF1/Cip1 protein. Analysis of the data suggests that overexpression of p21WAF1/Cip1 in intracranial GCTs may correlate with decreased sensitivity to radio- and chemotherapy and suggest a poor prognosis.
Occult neurohypophyseal germinomas in patients presenting with central diabetes insipidus
Authors: Kato Tsutomu , Sawamura Yutaka , Tada Mitsuhiro , Murata Jun-ichi , Abe Hiroshi , Shirato Hiroki , Fujieda Kenji 
Published: January 2008

Although neurohypophyseal germinoma is known be a common initial symptom in cases of diabetes insipidus (DI), its radiological detection may take months or years even by a high-resolution magnetic resonance (MR) imaging. The term “occult neurohypophyseal germinoma” denotes such cases, but its clinical picture remains obscure.
Of seven patients with neurohypophyseal germinoma presenting with DI during the last 5 years, three patients showed no evidence of tumor at the onset of DI and were treated as “idiopathic” DI. Neurohypophyseal germinoma was eventually diagnosed in these three patients as the tumor became evident on sequential MR imaging studies and the patients were successfully treated with chemotherapy and radiation therapy. To delineate the clinical features of the occult neurohypophyseal germinoma, the authors analyzed endocrinological aspects and MR images in these patients and compared them with those in two patients with true idiopathic DI and four patients with overt neurohypophyseal germinoma and DI. Nine previously reported cases in the literature were reviewed. During the stage at which the germinoma gave no notable change on MR images, patients often displayed anterior pituitary dysfunction, particularly growth hormone (GH) deficiency, or an elevation of serum or cerebrospinal fluid human chorionic gonadotropin-beta. Preceding the appearance of an obvious tumor mass, a slight swelling of the pituitary stalk with loss of normal hyperintensity of the posterior pituitary lobe was a common finding on MR imaging.
Central DI associated either with an enlarged stalk, decreased GH secretion, or an elevated serum human chorionic gonadotropin-beta should prompt the diagnosis of an occult germinoma.
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: January 2008

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.
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).
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.
Clinical practice guidelines and their role in quality of care assessments
Authors: Gerszten Peter C. 
Published: January 2008

Clinical practice guidelines may be defined as systematically developed statements to assist practitioner and patient decisions about appropriate healthcare for specific clinical conditions. The practice guideline is a management plan that enables healthcare providers to make sequential decisions about testing or therapy in a given clinical situation. Given the heterogeneity of disease presentations and the complexity of making therapeutic decisions, the development of guidelines in neurosurgery presents unique problems and challenges. Clinical practice guidelines were developed in part as a method for the assessment of quality of medical care processes. Practice guidelines serve as a tool for comparisons to be made within and between healthcare delivery systems. The implementation of guidelines also allows for the acquisition of clinical and financial data that provide for outcomes analysis and other types of information. The characterization of patterns of care in different institutions and the relationship between patterns of care and outcomes will in the future allow for quality improvement, enable physicians to offer predictability and accountability to third-party interests, and contribute to an understanding of how to offer the best care to neurosurgical patients.
The author provides an overview of clinical practice guidelines and illustrates their role in the assessment of quality of patient care, demonstrates how they fit into the methodology of quality assessments, and underscores the importances of practice quidelines for the development of disease management systems.
The influence of secondary gain on surgical outcome: a comparison between cervical and lumbar discectomy
Authors: Kaptain George J. , Shaffrey Christopher I. , Alden Tord D. , Young Jacob N. , Whitehill Richard 
Published: January 2008

Although the expectation of monetary compensation has been associated with failures in lumbar discectomy, the issue has not been investigated in patients undergoing cervical disc surgery. The authors analyzed the relationship between economic forms of secondary gain and surgical outcome in a group of patients with a common pay scale, retirement plan, and disability program.
All procedures were performed at the Portsmouth Naval Medical Center between 1993 and 1995; active-duty military servicepersons treated for cervical radiculopathy were prospectively included. Clinical, demographic, and financial factors were analyzed to determine which were predictive of outcome. Financial data were used to create a compensation incentive, which is proportional to the patient's rank, years of service, potential disability, retirement eligibility, and base pay and reflects the monetary incentive of disability. The results of cervical surgery were compared to a previously reported companion population of patients treated for lumbar disc disease. A good outcome was defined as a return to active duty, whereas a referral for disability was considered a poor surgical result. A 100% follow-up rate was obtained for 269 patients who underwent 307 cervical operations. Only 16% (43 of 269) of patients who underwent cervical operation received disability, whereas 24.7% (86 of 348) of patients who underwent lumbar discectomy obtained a poor result (p = 0.0082). Although economic forms of secondary gain were not associated with a poor outcome in cervical disease, both the rank (p = 0.002) and duration (p = 0.03) of an individual's military career were significant factors (p = 0.02). Of the medical variables tested, multilevel surgery (p = 0.03) and revision operations at the same level (p = 0.03) were associated with referral for medical discharge.
Secondary gain in the form of economic compensation influences outcome in lumbar but not cervical disc surgery patients; the increased rate of disability referral in patients who underwent lumbar discectomy may reflect an expectation of economic compensation. Social factors that are independent of the anticipation of economic compensation seem to influence the outcome in cervical disc surgery patients.
Outcomes after gamma knife radiosurgery in solitary acoustic tumors and neurofibromatosis Type 2
Authors: Kondziolka Douglas , Subach Brian R. , Lunsford L. Dade , Bissonette David J. , Flickinger John C. 
Published: January 2008

Surgeons perform stereotactic radiosurgery as the main alternative to acoustic tumor (vestibular schwannoma) resection. The goals of radiosurgery include preservation of neurological function and prevention of tumor growth. Longer-term outcomes are not well documented for patients with solitary tumors or those with neurofibromatosis Type 2 (NF2).
To define outcomes, the authors evaluated 462 consecutive patients with solitary acoustic tumors and 40 patients with NF2 (total of 45 tumors treated) who underwent radiosurgery between 1987 and 1998.
Serial imaging studies, clinical evaluations, and a patient survey were performed. The average tumor margin dose was 15 Gy, and the mean transverse tumor diameter was 22 mm. In patients with solitary tumors, prior resection had been performed in 111 patients (24%); 27 patients experienced tumor recurrence after a “total resection.”
The clinical tumor control rate (no resection required) was 98%. In non-NF2 patients followed for at least 5 years, 100 tumors (61.7%) were smaller, 53 (32.7%) remained unchanged in size, and nine (5.6%) were slightly larger. Resection was performed in four patients (2.4%). Neurological deficits after radiosurgery all occurred within the first 28 months. The rates of facial and trigeminal neuropathy varied with radiosurgery technique. In patients with NF2, 16 tumors were smaller, 28 remained unchanged, and one enlarged (overall 98% control rate at median 3-year follow up). Resection was performed in three patients (7%). Useful hearing was preserved in six (43%) of 14 NF2 patients who had useful hearing before radiosurgery.
Radiosurgery provided long-term tumor control associated with high rates of neurological function preservation. No further tumor surgery was necessary in 98% of patients with solitary tumors followed for a minimum of 5 years.
Combining endovascular and neurosurgical treatments of high-risk dural arteriovenous fistulas in the lateral sinus and the confluence of the sinuses
Authors: Goto Katsuya , Sidipratomo Prijo , Ogata Noboru , Inoue Toru , Matsuno Haruo 
Published: January 2008

The authors describe their experience in treating dural arteriovenous fistulas (DAVFs) in the lateral sinus and the confluence of sinuses in 17 patients who presented with signs and symptoms related to intracranial hemorrhage, infarction, and diffuse brain swelling. Angiographic examination revealed three different types of DAVFs in these high-risk patients: 1) extremely high flow DAVF not associated with sinus occlusion or leptomeningeal retrograde venous drainage (LRVD); 2) localized DAVF with exclusive LRVD and without sinus occlusion; and 3) diffuse DAVF with sinus occlusion and LRVD. Because of the complex nature of these lesions, the authors adopted a staged protocol in which they combined endovascular and surgical treatments.
The authors believe that by close collaboration between endovascular therapists and vascular neurosurgeons, high-risk DAVFs in the lateral sinus and the confluence of sinuses can be successfully treated without treatment-related morbidity and mortality.
Percutaneous transluminal angioplasty of intracranial artery stenosis: clinical results in 24 patients
Authors: Berg-Dammer Elisabeth , Henkes Hans , Weber Werner , Berlit Peter , Kühne Dietmar 
Published: January 2008

Circumscribed stenotic lesions of the intracranial arteries can cause cerebral ischemia by hemodynamic and/or thromboembolic mechanisms. Anticoagulation therapy, antiplatelet therapy, and bypass surgery are treatment strategies that have no direct impact on the underlying lesion. This study summarizes the experience of a single institution at which percutaneous transluminal angioplasty (PTA) of intracranial atherosclerotic stenoses was performed.
The authors performed a retrospective analysis of 24 consecutive patients. Their medical histories (cardiovascular risk factors, current clinical signs and symptoms and their duration, previous stroke[s], and medical treatment) were evaluated together with findings from previous imaging studies. The site and degree of the stenoses to be treated (target lesion) were identified with the use of ultrasound and angiography studies. Additional vascular stenoses were noted. Percutaneous transluminal angioplasty was performed using single-lumen balloon microcatheters with appropriate diameters. The results of PTA were correlated with angiographic and ultrasound findings and the clinical outcome.
Significant cardiovascular risk factors and clinical signs and symptoms related to the target lesion that persisted despite medical treatment were identified in all patients except one. The duration of symptoms varied from several days to 8 months. Previous stroke had occurred in four patients. The degree of stenosis was classified as “high grade” in 10 patients and as “subtotal” in 14. The target lesion (stenosis) was located in the anterior circulation in eight patients (four in the internal carotid and four in the middle cerebral arteries). Stenoses of posterior circulation vessels were treated in 16 patients (nine vertebral, six basilar, and one posterior cerebral arteries). Recanalization was rated “complete” in 15 patients and sufficient in six patients. In three patients residual stenosis remained. Complications were encountered in seven patients: two asymptomatic dissections, one transient vessel occlusion, one vessel occlusion with subsequent stroke, and three ischemic lesions likely due to thromboembolism, two of which caused only transient neurological symptoms.
Percutaneous balloon dilation proved effective in the treatment of intracranial atherosclerotic stenosis. There are, however, potential complications and experience with this procedure is only limited. Long-term results need to be determined. The authors conclude from their preliminary results that PTA may be an alternative to bypass surgery and conservative management and may be considered for patients in whom ischemic neurological symptoms persist despite medical treatment.