bluuebunny/crossref_metadata_2025_split huggingface dataset:
Incidence and clinical features of asymptomatic meningiomas
Authors: Kuratsu Jun-ichi , Kochi Masato , Ushio Yukitaka 
Published: May 2009

Object. The increased use of computerized tomography (CT) and magnetic resonance (MR) technology has led to an increase in the detection of asymptomatic meningiomas, although the surgical indication for these tumors remains undetermined. The authors investigated the incidence of asymptomatic meningiomas and their clinical features.Methods. An epidemiological survey was conducted of primary intracranial tumors diagnosed in Kumamoto Prefecture between 1989 and 1996. Follow-up neuroradiological imaging and clinical studies for asymptomatic meningiomas were performed.Primary intracranial tumors were diagnosed in 1563 residents. Of these lesions, 504 (32.2%) were meningiomas, and of these meningiomas 196 (38.9%) were asymptomatic. The incidence of asymptomatic meningiomas was significantly higher in individuals older than 70 years of age. Furthermore, the incidence of asymptomatic meningiomas was significantly higher in female than in male patients. Of the asymptomatic meningiomas in 196 patients, 87 (44.4%) were surgically removed, whereas 109 (55.6%) were treated conservatively. Of these conservatively treated patients, 63 received follow-up care for more than 1 year. In 20 of these 63 cases, the tumors increased in size over the 27.8-month average follow-up period (range 12–87 months), whereas in the other 43 cases, the tumor size did not increase during a 36.6-month average follow-up period (range 12–96 months). There was no significant difference with respect to age, tumor size, and male/female ratio between the patient group in which the tumor size increased and the group in which it did not increase during the follow-up period. Asymptomatic meningiomas that evidenced calcification on CT scans and/or hypointensity on T2-weighted MR images appear to have a slower growth rate.Conclusions. Among patients older than age 70 years who underwent operation for asymptomatic meningioma, the neurological morbidity rate was 23.3%; it was 3.5% among younger patients. This indicates that the advisability of surgery in elderly patients with asymptomatic meningiomas must be considered very carefully.
Bleeding risk of cerebral vascular malformations in hereditary hemorrhagic telangiectasia
Authors: Willemse Ronald B. , Mager Johannes J. , Westermann Cornelius J. J. , Overtoom Timotheus T. C. , Mauser Henk , Wolbers John G. 
Published: May 2009

Object. Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal-dominant vascular dysplasia with a high prevalence of cerebrovascular malformations (CVMs), mostly manifested as arteriovenous malformations (AVMs). The natural history and bleeding risk of these CVMs is unknown. The authors investigated the risk of bleeding in conjunction with clinical and radiological features in patients with HHT and proven CVMs.Methods. Intravenous digital subtraction (DS) angiography was used to screen 196 patients with HHT for the presence of CVMs. Patients with abnormal results on DS angiography were asked to undergo a conventional cerebral angiographic study. All patients with a proven CVM were assessed by a neurologist. The bleeding risk was retrospectively and prospectively calculated for patients with AVMs only, as well as for the whole cohort of patients with CVMs.Twenty-four patients (12.2%; 16 female and eight male), aged 14 to 66 years (mean 35.4 years) with one or more CVMs were identified. Fifteen patients (62.5%) had a CVM and a pulmonary AVM. Eleven patients (45.8%) exhibited no neurological signs of their CVM; six (25%) had headache or migraine; four (16.7%) had seizures; and three (12.5%) had an intracranial hemorrhage. Twenty-two patients had at least one AVM (with a total of 28 AVMs), whereas two patients only had telangiectases. Twenty-seven AVMs were small (96%), 36% were located in eloquent areas of the brain, and 82% had superficial venous drainage. One third of the patients had multiple CVMs. The bleeding risk for patients with at least one AVM ranged from 0.41 to 0.72% per year, and for the whole cohort the range was 0.38 to 0.69% per year. Calculation of the bleeding risk as determined by lesion-years ranged from 0.36 to 0.56% per year for patients with AVMs and from 0.27 to 0.46% per year for all patients with CVMs.Conclusions. Patients with HHT have a high risk of harboring a CVM, especially in the presence of a pulmonary AVM. These CVMs are mostly low-grade AVMs (Spetzler—Martin Grade I or II), are frequently multiple, and have a lower risk of bleeding than that associated with sporadic AVMs. Female patients are more often affected than male patients. The inherent low sensitivity of DS angiography screening for CVMs may yield false negative results.
Evaluation of a method for noninvasive intracranial pressure assessment during infusion studies in patients with hydrocephalus
Authors: Schmidt Bernhard , Czosnyka Marek , Schwarze Jens Jürgen , Sander Dirk , Gerstner Werner , Lumenta Christianto Benjamin , Klingelhöfer Jürgen 
Published: May 2009

Object. A mathematical model previously introduced by the authors allowed noninvasive intracranial pressure (nICP) assessment. In the present study the authors investigated this model as an aid in predicting the time course of raised ICP during infusion tests in patients with hydrocephalus and its suitability for estimating the resistance to outflow of cerebrospinal fluid (Rcsf).Methods. Twenty-one patients with hydrocephalus were studied. The nICP was calculated from the arterial blood pressure (ABP) waveform by using a linear signal transformation, which was dynamically modified by the relationship between ABP and cerebral blood flow velocity. This model was verified by comparison of nICP with “real” ICP measured during lumbar infusion tests. In all simulations, parallel increases in real ICP and nICP were evident. The simulated Rcsf was computed using nICP and then compared with Rcsf computed from real ICP. The mean absolute error between real and simulated Rcsf was 4.1 ± 2.2 mm Hg minute/ml. By the construction of simulations specific to different subtypes of hydrocephalus arising from various causes, the mean error decreased to 2.7 ± 1.7 mm Hg minute/ml, whereas the correlation between real and simulated Rcsf increased from R = 0.73 to R = 0.89 (p < 0.001).Conclusions. The validity of the mathematical model was confirmed in this study. The creation of type-specific simulations resulted in substantial improvements in the accuracy of ICP assessment. Improvement strategies could be important because of a potential clinical benefit from this method.
Efficacy of the Ghajar Guide revisited: a prospective study
Authors: O'Leary Shaun T. , Kole Max K. , Hoover Devon A. , Hysell Steven E. , Thomas Ajith , Shaffrey Christopher I. 
Published: May 2009

Object. The goal of this study was to compare the freehand technique of catheter placement using external landmarks with the technique of using the Ghajar Guide for this procedure. The placement of a ventricular catheter can be a lifesaving procedure, and it is commonly performed by all neurosurgeons. Various methods have been described to cannulate the ventricular system, including the modified Friedman tunnel technique in which a soft polymeric tube is inserted through a burr hole. Paramore, et al., have noted that two thirds of noninfectious complications have been related to incorrect positioning of the catheter.Methods. Forty-nine consecutive patients were randomized between either freehand or Ghajar Guide—assisted catheter placement. The target was the foramen of Monro, and the course was through the anterior horn of the lateral ventricle approximately 10 cm above the nasion, 3 cm from the midline, to a depth of 5.5 cm from the inner table of the skull. In all cases, the number of passes was recorded for successful cannulation, and pre- and postplacement computerized tomography scans were obtained. Calculations were performed to determine the bicaudate index and the distance from the catheter tip to the target point.Conclusions. Successful cannulation was achieved using either technique; however, the catheters placed using the Ghajar Guide were closer to the target.
Thymidine kinase activation of ganciclovir in recurrent malignant gliomas: a gene-marking and neuropathological study
Authors: Harsh Griffith R. , Deisboeck Thomas S. , Louis David N. , Hilton John , Colvin Michael , Silver Jonathan S. , Qureshi Nazer H. , Kracher Jean , Finkelstein Diane , Chiocca Ennino A. , Hochberg Fred H. 
Published: May 2009

Object. The gene therapy paradigm of intratumoral activation of ganciclovir (GCV) following transduction of tumor cells by retroviral vectors bearing the thymidine kinase (tk) gene has produced dramatic remissions of malignant gliomas in animal models. In human trials, although the technique has been deemed safe, little antitumor effect has been demonstrated. To evaluate the basis of this inefficacy in human gliomas, the authors conducted a gene-marking trial involving neuropathological and biochemical studies of treated tumor specimens.Methods. Five patients with malignant recurrent gliomas underwent stereotactic biopsy sampling and intratumoral implantation procedures with three aliquots of 106 vector-producing cells (VPCs) in columns. After 5 days, the tumor was resected and the tumor bed reimplanted with VPCs, and a course of GCV was given. Patients received clinical and radiological follow up for 6 months. Tumor specimens were analyzed neuropathologically and for tk gene expression by anti-TK immunohistochemistry and TK enzymatic activity.Four patients tolerated the treatment well but experienced tumor progression. The other developed an abscess after the second operation and died. Increased TK enzymatic activity was demonstrated in the one tumor specimen analyzed. Immunohistochemical evidence of tk gene expression was limited to VPCs. Transduction of tumor cells was not seen. Viable tumor cells were seen near VPCs containing TK. The lymphocytic immune response was mild.Conclusions. Except for the risk of infection inherent in reoperation, this tk—GCV paradigm was both feasible and safe. Pathological studies indicated that limited dissemination of VPCs and vector from the infusion site and failure to transduce tumor cells with the tk gene are major barriers to efficacy.
Quantitative description of the far-lateral transcondylar transtubercular approach to the foramen magnum and clivus
Authors: Spektor Sergey , Anderson Gregory J. , McMenomey Sean O. , Horgan Michael A. , Kellogg Jordi X. , Delashaw Johnny B. 
Published: May 2009

Object. The purpose of this study was to evaluate the far-lateral transcondylar transtubercular approach (complete FLA) based on quantitative measurements of the exposure of the foramen magnum and petroclival area obtained after each successive step of this approach.Methods. The complete FLA was reproduced in eight specially prepared cadaveric heads (a total of 15 sides). The approach was divided into six steps: 1) C-1 hemilaminectomy and suboccipital craniectomy with unroofing of the sigmoid sinus (basic FLA); 2) partial resection of the occipital condyle (up to the hypoglossal canal); 3) removal of the jugular tuberculum; 4) mastoidectomy (limited to the labyrinth and the fallopian canal) and retraction of the sigmoid sinus; 5) resection of the lateral mass of C-1 with mobilization of the vertebral artery; and 6) resection of the remaining portion of the occipital condyle. After each successive step, a standard set of measurements was obtained using a frameless stereotactic device. The measurements were used to estimate two parameters: the size of the exposed petroclival area and the size of a spatial cone directed toward the anterior rim of the foramen magnum, which depicts the amount of surgical freedom available for manipulation of instruments.The initial basic FLA provided exposure of only 21 ± 6% of the petroclival area that was exposed with the full, six-step maximally aggressive (complete) FLA. Likewise, only 18 ± 9% of the final surgical freedom was obtained after the basic FLA was performed. Each subsequent step of the approach increased both petroclival exposure and surgical freedom. The most dramatic increase in petroclival exposure was noted after removal of the jugular tuberculum (71 ± 12% of final exposure), whereas the least improvement in exposure occurred after the final step, which consisted of total condyle resection.Conclusions. The complete FLA provides wide and sufficient exposure of the foramen magnum and lower to middle clivus. The complete FLA consists of several steps, each of which contributes to increasing petroclival exposure and surgical freedom. However, the FLA may be limited to the less aggressive steps, while still achieving significant exposure and surgical freedom. The choice of complete or basic FLA thus depends on the underlying pathological condition and the degree of exposure required for effective surgical treatment.
Telomerase activity and expression of the telomerase catalytic subunit, hTERT, in meningioma progression
Authors: Simon Matthias , Park Tjoung-Won , Leuenroth Sven , Hans Volkmar H. J. , Löning Thomas , Schramm Johannes 
Published: May 2009

Object. In recent reports, 6 to 19% of meningiomas have been classified as atypical or anaplastic/malignant. Some atypical and anaplastic meningiomas appear to arise from benign tumors by progression. Telomerase activation has recently been associated with malignant progression of human tumors. The authors have investigated a series of benign, atypical, and anaplastic/malignant meningiomas for telomerase activity and expression of the telomerase catalytic subunit human telomerase reverse transcriptase (hTERT).Methods. A quantitative telomeric repeat amplification protocol was used to detect telomerase enzyme activity in seven (21%) of 34 benign, but in nine (75%) of 12 atypical and in seven (100%) of seven anaplastic/malignant meningiomas. Very high levels of telomerase activity were observed only in highly aggressive tumors. Messenger (m)RNA expression of the catalytic subunit hTERT was found in 11 (33%) of 33 benign, 12 (92%) of 13 atypical, and all seven anaplastic/malignant tumors. All telomerase-positive lesions were also positive for hTERT mRNA, whereas no telomerase activity was detected in six (21%) of 29 hTERT-positive tumors. This indicates that upregulation of hTERT is the rate-limiting step for telomerase activation in the majority of meningiomas. Expression of telomerase and hTERT was seen in all four tumors with gross brain invasion. All recurrent tumors or meningiomas recurring during follow up expressed hTERT.Conclusions. The results are consistent with a role for telomerase activation during the development of malignancy in meningiomas. Hence, expression of telomerase activity and hTERT might prove to be potentially useful markers for the evaluation of these tumors.
Imaging correlates of successful endoscopic third ventriculostomy
Authors: Kulkarni Abhaya V. , Drake James M. , Armstrong Derek C. , Dirks Peter B. 
Published: May 2009

Object. The goal of this study was to determine and compare imaging correlates in pediatric patients who underwent successful or failed endoscopic third ventriculostomies (ETVs). To this end, the authors measured ventricular size changes and the presence of cerebrospinal fluid (CSF) flow void in both groups of children following ETV.Methods. Images obtained in children with hydrocephalus immediately before and at least 30 days after having undergone ETV were reviewed by four independent observers (two blinded and two nonblinded). Each observer independently measured the frontal and occipital horn ratio ([FOR], a reliable and valid measure of ventricular size) and provided a subjective assessment of the presence of a flow void at the ETV site, the degree of periventricular edema, and the amount of CSF over the cerebral hemispheres.There were 29 children whose mean age was 6.6 years at the time of ETV and who had a mean postoperative follow-up period lasting 1.6 years. Postoperatively, the mean reduction in ventricular size (as measured using the FOR) was 7% (95% confidence interval [CI] 3–11%) in cases that were deemed failures (eight patients) and 16% (95% CI 12–20%) in clinically successful cases (21 patients). This reduction was significantly greater in cases of clinical success compared with those that were deemed failures (p = 0.03, t-test). There were no substantial differences between blinded and nonblinded assessments. Flow void was present in 94% of successes and absent in 75% of failures (p = 0.01, Fisher's exact test). The other subjective assessments were not significantly different between the groups of successes and failures.Conclusions. Ventricular size appears to be somewhat reduced in both groups of patients who underwent clinically successful and failed ETV; however, the reduction is significantly greater among clinically successful cases. The presence of a flow void also appears to correlate with clinical success and its absence with clinical failure.
Asymptomatic Chiari Type I malformations identified on magnetic resonance imaging
Authors: Meadows Jeffery , Kraut Michael , Guarnieri Michael , Haroun Raymond I. , Carson Benjamin S. 
Published: May 2009

Object. Chiari Type I malformation (CMI) is a congenital disorder recognized by caudal displacement of the cerebellar tonsils through the foramen magnum and into the cervical canal. Frequently, associated findings include abnormalities of nearby bony and neural elements as well as syringomyelia. Cerebellar tonsillar ectopia is generally considered pathological when greater than 5 mm below the foramen magnum. However, asymptomatic tonsillar ectopia is an increasingly recognized phenomenon, the significance of which is poorly understood.Methods. The authors retrospectively reviewed the records of all brain magnetic resonance (MR) images obtained at our hospital over a 43-month period in an attempt to ascertain the relative prevalence and MR imaging characteristics of asymptomatic CMIs. Of 22,591 patients who underwent MR imaging of the head and cervical spine, 175 were found to have CMIs with tonsillar herniation extending more than 5 mm below the foramen magnum. Of these, 25 (14%) were found to be clinically asymptomatic. The average extent of ectopia in this population was 11.4 ± 4.86 mm, and was significantly associated with a smaller cisterna magna. Syringomyelia and osseous anomalies were found in only one asymptomatic patient.Conclusions. The authors suggest that the isolated finding of tonsillar herniation is of limited prognostic utility and must be considered in the context of all available clinical and radiographic data. Strategies for treating patients with asymptomatic CMIs are discussed.
Preoperative embolization of cerebral arteriovenous malformations with silk sutures: analysis and clinical correlation of complications revealed on computerized tomography scanning
Authors: Song Joon K. , Eskridge Joseph M. , Chung Eun-Chul , Blake Lindsey C. , Elliott J. Paul , Finch Lisa , Niakan Cyrus , Maravilla Kenneth R. , Winn H. Richard 
Published: May 2009

Object. The aim of this study was to determine the incidence and clinical significance of complications related to preoperative embolization of cerebral arteriovenous malformations (AVMs) with silk sutures as documented on postprocedure computerized tomography (CT) scans.Methods. The CT scans were obtained within 12 to 24 hours after 221 (96%) of 230 consecutive embolizations in 70 patients. These CT scans were evaluated for the presence of ischemia, infarction, hemorrhage, or contrast agent extravasation. Adverse patient outcomes were determined after each embolization and were correlated with CT findings. New abnormalities demonstrated on CT scans were also correlated with the Spetzler—Martin AVM grade, degree of arteriovenous shunting, and location. New abnormalities, the majority of them infarcts, resulted from 29 (13%) of 221 embolization procedures. In 11 (38%) of 29 cases of new CT findings, patients were asymptomatic, including 10 with new infarcts on CT scans. New neurological deficits occurred in 20 (8.7%) of 230 total embolization procedures in 19 patients, including one death. Permanent deficits occurred in nine patients (3.9% per embolization procedure, 12.8% per patient). Of the patients with new neurological deficits, 18 (90%) of 20 embolization procedures resulted in new abnormalities on CT scans. Two patients with new transient neurological deficits had no new findings on CT scans. Spetzler—Martin grade, AVM location, degree of arteriovenous shunting, and higher numbers of procedures were not statistically associated with a higher incidence of abnormalities on CT scans or new permanent neurological deficits.Conclusions. Silk sutures are an effective and relatively safe embolic agent. After brain AVM embolization with silk sutures, new abnormalities were found on CT scans obtained in one of eight procedures. When a new CT finding occurred, the patient had roughly equal chances of having no new symptoms, having new transient neurological deficits, or having new permanent neurological deficits.
Adverse effects of limited hypotensive anesthesia on the outcome of patients with subarachnoid hemorrhage
Authors: Chang Han Soo , Hongo Kazuhiro , Nakagawa Hiroshi 
Published: May 2009

Object. This study was aimed at clarifying the effect of intraoperative hypotensive anesthesia on the outcome of early surgery in patients with subarachnoid hemorrhage (SAH) caused by saccular cerebral aneurysms. Other factors were also screened for possible effects on the outcome.Methods. Hospital charts in 84 consecutive patients with SAH who underwent aneurysm clipping by Day 4 were examined. Possible factors affecting the outcome were analyzed using multiple logistic regression with the dichotomous Glasgow Outcome Scale score as the outcome variable. The relationship between the intraoperative hypotension and the occurrence and severity of vasospasm was studied using both single- and multivariate analyses.Conclusions. Intraoperative hypotension had a significantly adverse effect on the outcome of SAH. Hypotension was also related to more frequent and severe manifestations of vasospasm. A long-lasting effect of brain retraction is possibly the cause of this phenomenon. The data contained in this study preclude the use of intraoperative hypo- tension even in a limited form.