bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of hearing loss after shunt placement in patients with normal-pressure hydrocephalus
Authors: van Veelen-Vincent Marie-Lise C. , Delwel Ernst J. , Teeuw Rozemarijn , Kurt Erkan , de Jong Dirk A. , Brocaar Michel P. , Pauw Bernard K. H. , Avezaat Cees J. J. , van Zanten Bert G. A.
Published: May 2009

Object. Following shunt placement for treatment of normal-pressure hydrocephalus (NPH), several patients suffered hearing loss. The authors undertook a study to analyze this outcome.

Methods. Sixteen patients in whom NPH was diagnosed were treated by placement of a ventriculoperitoneal shunt. Their hearing was assessed pre- and postoperatively by using pure tone audiometry. Two thirds of the ears tested showed a postoperative hearing loss of more than 10 dB. Recovery of the hearing loss occurred 6 to 12 weeks after shunt placement in 75% of the ears examined.

Conclusions. Although shunt insertion for treatment of NPH results in a decrease in hearing, most of the loss can be recovered.
Nestin expression in cortical dysplasia
Authors: Duggal Neil , Iskander Sam , Hammond Robert R.
Published: May 2009

Object. It is recognized that cortical dysplasia (CD) is associated with an increased incidence of glioneuronal neoplasms. Among hypothetical considerations, there is the possibility that CD and other neuronal migration abnormalities harbor dysmature cells with the potential to give rise to glioneuronal neoplasms. Such cells, if present, would be reasonably expected to display immature features. The goal of the present study was to characterize the expression of nestin, a neuroepithelial precursor/stem cell antigen, in CD, along with other pathological and clinical features of this entity.

Methods. Clinical and surgical features of 10 recent cases meeting the histological criteria for CD were reviewed. Expressions of nestin, MAP2, neurofilament, and glial fibrillary acidic protein (GFAP) were assessed using immunohistochemical analysis and confocal scanning laser microscopy.

Immunoreactivity for both glial and neuronal antigens as well as nestin was found in a select group of cells within regions of CD. Immunohistochemical and confocal microscopic findings demonstrated that these cells with neuronal or ambiguous features are a mixed population, some of which are dysmature neurons (positive for nestin and MAP2), whereas others are astrocytic (positive for nestin and GFAP).

Conclusions. Further insight into the nature of nestin-positive neurons may shed light on the cause and pathogenesis of the associated glioneuronal tumors and the accompanying chronic seizures.
Improvement of endothelial function in insulin-resistant carotid arteries treated with pravastatin
Authors: Dumont Aaron S. , Hyndman M. Eric , Dumont Randall J. , Fedak Paul M. , Kassell Neal F. , Sutherland Garnette R. , Verma Subodh
Published: May 2009

Object. Insulin resistance and hypertension are independent risk factors for stroke. Endothelial dysfunction in response to risk factors and carotid artery (CA) disease are important in the pathogenesis of stroke. Pravastatin may have cholesterol-independent pleiotropic effects. In the present study the authors examined the effects of short-course pravastatin treatment on endothelial function in CAs obtained in control and insulin-resistant rats with fructose-induced hypertension.

Methods. Thirty rats were divided into two experimental groups, in which 14 were fed a regular diet and 16 were fed a fructose-enriched diet for 3 weeks. The rats were then divided into four groups: control, pravastatin-treated control, fructose-fed, and pravastatin-treated fructose-fed. Pravastatin was administered (20 mg/kg/day) for 2 weeks. Excretion of the urinary nitric oxide (NO) metabolite nitrite (NO2−) was also assayed. The CAs from all rats were subsequently removed and assessed for endothelium-dependent and -independent vascular reactivity in vitro. The rats in the fructose-fed group were insulin resistant, hyperinsulinemic, and hypertensive relative to the rats in the control and pravastatin-treated control groups and exhibited diminished endothelium-dependent vasomotion and urinary NO2− excretion (p < 0.05), with preserved endothelium-independent vasomotion. Strikingly, pravastatin treatment restored endothelium-dependent vasomotion and urinary NO2− excretion in rats in the fructose-fed pravastatin-treated relative to the fructose-fed group (p < 0.05).

Conclusions. The authors report, for the first time, that pravastatin restores endothelial function in CAs from insulin-resistant rats with fructose-induced hypertension. These beneficial effects were ascribed to direct, cholesterol-independent vascular effects of pravastatin and are likely the result of augmentation of NO production. These data provide impetus for further investigation of nonlipid-lowering indications for pravastatin therapy in the prevention and treatment of CA disease.
Possible control of intermittent cerebral ischemia by monitoring of direct-current potentials
Authors: Sakaki Takayuki , Graf Rudolf , Nozaki Hiroyuki , Rosner Gerhard , Heiss Wolf-Dieter
Published: May 2009

Object. Neurosurgically induced temporary occlusion of intracranial arteries carries the risk of cerebral ischemic damage. Because negative shifts in the cortical direct-current (DC) potential indicate tissue depolarization and, thus, critical ischemic stress, the authors hypothesized that recordings of these potentials could help to determine the optimal duration and frequency of induced intermittent focal ischemia to prevent brain injury. The investigators related the results of DC recordings both to simultaneously recorded decreases in extracellular Ca++ concentration ([Ca++]o), which reflect Ca++ entry into cells, and to histological outcome.

Methods. In cats anesthetized with halothane the effects of intermittent brief (10 minutes long, six times [6 × 10-min group]) and prolonged (20 minutes long, three times [3 × 20-min group]) episodes of middle cerebral artery occlusions were compared with those of a single continuous episode (1 × 60-min group). Laser Doppler flow probes and ion-selective microelectrodes were used to measure cerebral blood flow, DC potentials, and [Ca++]o in cortical tissues of ectosylvian gyri.

Negative shifts in DC potential were evaluated in the three groups during the entire 60-minute-long period of ischemia and were smallest in the 6 × 10-min group, larger in the 3 × 20-min group, and largest in the 1 × 60-min group. Accordingly, infarct volumes were smallest in the 6 × 10-min group, intermediate in the 3 × 20-min group, and largest in the 1 × 60-min group. Decreases in ischemic [Ca++]o were significantly greater in the 1 × 60-min group than in the two groups in which there were repetitive occlusions, and recovery of [Ca++]o after reperfusion normalized only in the 1 × 60-min group.

Conclusions. The DC potential may provide a reliable measure to optimize intermittent ischemia and to achieve minimal ischemic brain injury during temporary neurosurgical occlusion of cerebral arteries.
Methods of experimental and clinical assessment of the relative measurement accuracy of an intracranial pressure transducer
Authors: Morgalla Matthias Hubert , Krasznai Làszlo , Dietz Klaus , Mettenleiter Holger , Deininger Martin , Grote Ernst Heinrich
Published: May 2009

✓ The assessment of the actual measurement accuracy of an intracranial pressure (ICP) transducer is imperative but still very difficult in practice. The authors tested the Codman MicroSensor ICP transducer experimentally. Additionally, a bedside test for assessment of measurement accuracy was used before and after clinical monitoring. For laboratory testing, seven new transducers were examined for measurement accuracy at increasing pressures ranging from 0 to 75 mm Hg. Drift was evaluated for 10 days at six different pressure levels ranging from 0 to 50 mm Hg. Temperature drift was assessed over a temperature range from 20 to 45°C. The percentage absolute difference was used in the assessment of measurement accuracy. For clinical testing, measurement accuracy was assessed intraoperatively just before the insertion of the transducer and in an open water bath after its explantation, at 10 cm H2O both times.

The maximum percentage absolute difference was 9% at a pressure of 10 mm Hg, and declined toward 2.3% at a pressure of 75 mm Hg. The maximum drift over 10 days was −4 mm Hg. Within the range of 30 to 40°C, temperature drift was negligible. Over a period of 2 years, between June 1997 and June 1999, 40 ICP transducers were implanted in 35 patients by one surgeon. Of these devices, a malfunction was detected in two of them by testing them in a water bath before insertion. Experimental and clinical results indicate that this miniature strain-gauge transducer measures accurately; however, control readings for the probe by means of measurement in an open water bath just before insertion are strongly recommended.
Influence of premorbid factors on survival following subarachnoid hemorrhage
Authors: Pobereskin Louis H.
Published: May 2009

Object. The goal of this study was to explore the relationships between premorbid patient characteristics, especially cigarette smoking, and the risk of death following subarachnoid hemorrhage (SAH).

Methods. A population-based study design was used with multiple overlapping methods of case identification. A strict definition of SAH was used. Relationships between patients' age and sex as well as their cigarette smoking and hypertension statuses were explored by calculating relative risks (RRs). Confounding effects were examined using logistic regression analysis.

The author identified 800 cases in which the patient had experienced his or her first SAH. Seventy-seven percent of cases were verified by review of computerized tomography scans, 22% by autopsy, and 1% by lumbar puncture. A prior history of hypertension had no effect on the risk of mortality. There was a higher case mortality rate in female patients than in male patients, but this did not reach statistical significance. The RR of death at 30 days post-SAH for patients older than 60 years compared with those who were younger was 2.95 (95% confidence interval [CI] 2.18–3.97). The RR of death at all time intervals was lower for smokers than for nonsmokers (smokers/nonsmokers RR 0.47 [95% CI 0.32–0.69] at 7 days). The protective effect of smoking diminished on Day 3 post-SAH and increased again on Day 7.

Conclusions. Advanced age is an important determinant of survival following SAH. Smoking appears to have a protective effect. The author presents evidence indicating that increased vasospasm in smokers may reduce the severity of the initial hemorrhage.
Surgical management and outcome in patients with radial nerve lesions
Authors: Kim Daniel H. , Kam Andrew C. , Chandika Padmavathi , Tiel Robert L. , Kline David G.
Published: May 2009

Object. The goal of this paper was to review surgical management and outcomes in patients treated for radial nerve (RN) lesions at Louisiana State University Health Sciences over a period of 30 years.

Methods. Two hundred sixty patients with RN injuries were evaluated. The most common mechanisms of injuries involving the RN included fracture of the humerus, laceration, blunt contusions, and gunshot wounds. One hundred and eighty patients (69%) underwent surgery. Lesions not in continuity required primary or secondary end-to-end suture repairs or graft repairs. With the use of direct intraoperative nerve action potential recording, RN injuries in which the lesion was in continuity required external or internal neurolysis or resection of the lesion followed by end-to-end suture or graft repair. A minimum of 1.5 years follow-up review was available in 90% of the patients who underwent surgery. Motor function recovery to Grade 3 or better was observed in 10 (91%) of 11 patients who underwent primary suture repair, 25 (83%) of 30 who underwent secondary suture repair, 43 (80%) of 54 who received graft repair, and 63 (98%) of 64 in whom neurolysis was performed. Sixteen (71%) of 21 patients with superficial sensory RN injury achieved satisfactory pain relief after complete resection of a neuroma or neurolysis.

Conclusions. This study clearly demonstrates that excellent functional recovery can be achieved with proper surgical management of RN injuries.
Predictive value of progression-associated chromosomal aberrations for the prognosis of meningiomas: a retrospective study of 198 cases
Authors: Ketter Ralf , Henn Wolfram , Niedermayer Isolde , Steilen-Gimbel Heike , König Jochem , Zang Klaus D. , Steudel Wolf-Ingo
Published: May 2009

Object. The goal of this study was to determine whether in meningiomas cytogenetic findings are suitable as a predictive parameter relevant to prognosis.

Methods. Between 1992 and 1998 at the Department of Neurosurgery, Saarland University, 198 patients underwent surgery to resect meningiomas. The meningiomas were investigated cytogenetically and the patients were followed up for a mean period of 33 months.

On the basis of the cytogenetic findings, the meningiomas were subdivided into four groups: Group 0 meningiomas displayed a normal diploid chromosome set; Group 1 tumors were found to have monosomy 22 as the sole cytogenetic aberration; Group 2 tumors were markedly hypodiploid meningiomas with loss of additional autosomes in addition to monosomy 22; and Group 3 meningiomas had deletions of the short arm of a chromosome 1, as well as additional chromosomal aberrations including loss of one chromosome 22.

One hundred ninety-eight patients in whom tumor resections were determined to be Simpson Grade I or II could be followed up after complete tumor extirpation. In 20 patients, one or several recurrences were documented during the period of observation. The tumors were classified according to their different, but mostly uniform chromosomal aberrations. Recurrences were found in six (4.3%) of 139 tumors in Groups 0 and 1 and in two (10.5%) of 19 tumors in Group 2; the highest rate of recurrence was found in 12 (30%) of 40 tumors in Group 3. This supports the notion that the deletion of the short arm of one chromosome 1 is an important prognostic factor in meningiomas. The results of this study document a significant correlation between histological grade (p < 0.0001), location (p < 0.0001), and recurrences of meningiomas (p < 0.0001) (significance determined using chi-square tests).

Conclusions. The cytogenetic classification of meningiomas provides a significant contribution to the predictability of tumor recurrence and is, therefore, a valuable criterion for the neurosurgeon's postoperative management protocol.
Population-based analysis of arteriovenous malformation treatment
Authors: Hillman Jan
Published: May 2009

Object. The author sought to describe overall management data on cerebral arteriovenous malformations (AVMs) and to focus the actuarial need for different treatment modalities on a population-based scale. Such data would seem important in the planning of regional or national multimodality strategies for the treatment of AVMs. This analysis of a nonselected, consecutive series of patients representing every diagnosed case of cerebral AVM in a population of 1,000,000 over one decade may serve to shed some light on these treatment aspects.

Methods. During the 11-year period from 1989 to 1999, data from every patient harboring a cerebral AVM that was presented clinically or discovered incidentally in a strictly defined population of 986,000 people were collected prospectively. No patient was lost to follow up. There were 12.4 de novo diagnosed AVMs per 1,000,000 population per year (135 AVMs). Large high-grade AVMs (Spetzler—Martin classification) were rare, and Grade 1 to 3 lesions represented 85% of the caseload. Hemorrhage was the initial manifestation of AVM in 69.6% of the cases. Intracerebral hematoma was the most common hemorrhagic manifestation occurring in 78 patients. There were 4.4 cases per 1,000,000 population per year of hematomas needing expedient surgical evacuation. In the remaining patients who did not require hematoma surgery, small, critically located Grade 3 and Grade 4 lesions amounted to 1.6 cases per 1,000,000 population per year. There were 5.8 cases per 1,000,000 population per year of Grade 1 to 2 and larger noncritically located Grade 3 malformations. There were 0.5 cases per 1,000,000 population per year of Grade 5 AVMs. The overall outcome in 135 patients was classified as good according to the Glasgow Outcome Scale (Score 5) in 61% of the cases, and the overall mortality rate was 9%.

Conclusions. In centers with population-based referral, AVM of the brain is predominantly a disease related to intracranial bleeding, and parenchymal clots have a profound impact on overall management outcome. The rupture of an AVM is as devastating as that of an aneurysm. Aneurysm ruptures are more lethal, whereas AVM rupture tends to result in more neurological disability due to the high occurrence of lobar intracerebral hematoma. In an attempt to quantify the need for different modalities of AVM treatment based on a population of 1,000,000 people, figures for surgeries performed range from six to 10 operations per year and embolization as well as gamma knife surgery procedures range from two to seven per year, depending on the strategy at hand. When using nonsurgical approaches to Grade 1 to 3 lesions, the number of patients requiring treatment with more than one method for obliteration increases drastically as does the potential risk for procedure-related complications.
Analysis of loss of heterozygosity for chromosome 10 in patients with malignant astrocytic tumors: correlation with patient age and survival
Authors: Tada Kenji , Shiraishi Shoji , Kamiryo Takanori , Nakamura Hideo , Hirano Hirofumi , Kuratsu Jun-Ichi , Kochi Masato , Saya Hideyuki , Ushio Yukitaka
Published: May 2009

Object. The most frequent genetic abnormality in human malignant gliomas is loss of heterozygosity (LOH) on chromosome 10. Candidate genes on chromosome 10 that are associated with the prognosis of patients with anaplastic astrocytoma (AA) and glioblastoma (GBM) were evaluated.

Methods. The authors used 12 fluorescent microsatellite markers on both arms of chromosome 10 to study LOH in 108 primary astrocytic tumors. The LOH on chromosome 10 was observed in 11 (32%) of 34 AAs and 34 (56%) of 61 GBMs. No LOH was detected in 13 low-grade gliomas. Loss of heterozygosity was not detected in any AA in the seven patients younger than 35 years, but it was discovered in 41% of the patients older than 35 years. The prognostic significance of LOH at each locus was evaluated in 89 patients older than 15 years; 33 (37%) had supratentorial AAs and 56 (63%) had supratentorial GBMs. The Cox proportional hazards model, adjusted for patient age at surgery, the preoperative Karnofsky Performance Scale score, and the extent of surgical resection revealed that LOH on marker D10S209 near the FGFR2 and DMBT1 genes was significantly associated with shorter survival in patients with AA. The LOH on markers D10S215 and D10S541, which contain the PTEN/MMAC1 gene between them, was significantly associated with shorter survival in patients with GBM.

Conclusions. In the present study it is found that LOH on chromosome 10 is an age-dependent event for patients with AAs and that LOH on marker D10S209 near the FGFR2 and DMBT1 loci is a significantly unfavorable prognostic factor. It is also reported that LOH on the PTEN/MMAC1 gene is a significantly unfavorable prognostic factor in patients with GBM.
Attenuation of intracerebral hemorrhage and thrombin-induced brain edema by overexpression of interleukin-1 receptor antagonist
Authors: Masada Tetsuya , Hua Ya , Xi Guohua , Yang Guo-Yuan , Hoff Julian T. , Keep Richard F.
Published: May 2009

Object. Adenovirus-mediated overexpression of interleukin-1 receptor antagonist (IL-1ra) attenuates the inflammatory reaction and brain injury that follows focal cerebral ischemia. Recently, an inflammatory reaction after intracerebral hemorrhage (ICH) was identified. In this study the authors examine the hypothesis that overexpression of IL-1ra reduces brain injury (specifically edema formation) after ICH.

Methods. Adenoviruses expressing IL-1ra (Ad.RSVIL-1ra) or LacZ, a control protein (Ad.RSVlacZ), or saline were injected into the left lateral cerebral ventricle in rats. On the 5th day after virus injection, 100 µl of autologous blood or 5 U thrombin was infused into the right basal ganglia. Rats with ICH were killed 24 or 72 hours later for measurement of brain water and ion content. Thrombin-treated rats were killed 24 hours later for edema measurements and an assessment of polymorphonuclear leukocyte (PMNL) infiltration by myeloperoxidase (MPO) assay, as well as histological evaluation. Compared with saline-treated and Ad.RSVlacZ—transduced controls, Ad.RSVIL-1ra-transduced rats had significantly attenuated edema in the ipsilateral basal ganglia 3 days after ICH (81.5 ± 0.3% compared with 83.4 ± 0.4% and 83.3 ± 0.5% in control animals). Thrombin-induced brain edema was also reduced in Ad.RSVIL-1ra—treated rats (81.3 ± 0.4% compared with 83.2 ± 0.4% and 82.5 ± 0.4% in control rats). The reduction in thrombin-induced edema was associated with a reduction in PMNL infiltration into the basal ganglia, as assessed by MPO assay (49% reduction) and histological examination.

Conclusions. Overexpression of IL-1ra by using an adenovirus vector attenuated brain edema formation and thrombin-induced intracerebral inflammation following ICH. The reduction in ICH-induced edema with IL-1ra may result from reduction of thrombin-induced brain inflammation.
Effect of absorbable topical hemostatic agents on the relaxation time of blood: an in vitro study with implications for postoperative magnetic resonance imaging
Authors: Spiller Marga , Tenner Michael S. , Couldwell William T.
Published: May 2009

Object. Absorbable topical hemostatic agents are commonly used in neurosurgery. In this study the authors examine the longitudinal relaxation time (T1) of blood in contact with these agents over time, measured in vitro, to determine if their presence could affect the interpretation of postoperative magnetic resonance (MR) images.

Methods. Coagulated and anticoagulated blood were used, both oxygenated and deoxygenated. The effects of a collagen-based agent (Collastat) and a cellulose-based agent (Surgicel) on the pH and T1 values of blood and on those of saline (used as a control) were investigated. The T1 was measured as a function of magnetic field strength and time by using a field-cycling relaxometer. This instrument measures 1/T1, the rate of T1, from which the T1 value is computed. The T1 values of blood were compared with those of hemostat-induced blood clots and with those of both gray and white matter of the brain. Signal changes on T1-weighted MR images were predicted on the basis of altered T1 values in vitro. Postoperative images were visually examined for the predicted changes. With the addition of Surgicel, blood had decreased pH and significantly shortened T1 at all fields, essentially within minutes, although it affected the T1 of saline only minimally. The effect of Surgicel increasingly shortened the T1 for 4 days in oxygenated blood. Collastat had no significant effect. The presence of some paramagnetic methemoglobin in Surgicel-induced clots was demonstrated using the relaxometer at a time when diamagnetic oxyhemoglobin would be present in naturally occurring blood clots. A bright signal that could mimic residual tumor on contrast-enhanced images was predicted and confirmed on postoperative T1-weighted MR images obtained in patients in whom Surgicel lined the tumor bed. It was not present in cases in which Surgicel was not used.

Conclusions. Surgicel alters the appearance of early postoperative MR images. To avoid misinterpretation, clinicians should be aware of this phenomenon.
Intercenter variance in clinical trials of head trauma—experience of the National Acute Brain Injury Study: Hypothermia
Authors: Clifton Guy L. , Choi Sung C. , Miller Emmy R. , Levin Harvey S. , Smith Kenneth R. , Muizelaar J. Paul , Wagner Franklin C. , Marion Donald W. , Luerssen Thomas G.
Published: May 2009

Object. In a recently conducted trial of hypothermia in patients with severe brain injury, differences were found in the effects of hypothermia treatment among various centers. This analysis explores the reasons for such differences.

Methods. The authors reviewed data obtained in 392 patients treated for severe brain injury. Prerandomization variables, critical physiological variables, treatment variables, and accrual methodologies were investigated among various centers. Hypothermia was found to be detrimental in patients older than the age of 45 years, beneficial in patients younger than 45 years of age in whom hypothermia was present on admission, and without effect in those in whom normothermia was documented on admission. Marginally significant differences (p < 0.054) in the intercenter outcomes of hypothermia-treated patients were likely the result of wide differences in the percentage of patients older than 45 years of age and in the percentage of patients in whom hypothermia was present on admission among centers. The trial sensitivity was likely diminished by significant differences in the incidence of mean arterial blood pressure (MABP) less than 70 mm Hg (p < 0.001) and cerebral perfusion pressure (CPP) less than 50 mm Hg (p < 0.05) but not intracranial pressure (ICP) greater than 25 mm Hg (not significant) among patients in the various centers. Hours of vasopressor usage (p < 0.03) and morphine dose (p < 0.001) and the percentage of dehydrated patients varied significantly among centers (p < 0.001). The participation of small centers increased intercenter variance and diminished the quality of data.

Conclusions. For Phase III clinical trials we recommend: 1) a detailed protocol specifying fluid and MABP, ICP, and CPP management; 2) continuous monitoring of protocol compliance; 3) a run-in period for new centers to test accrual and protocol adherence; and 4) inclusion of only centers in which patients are regularly randomized.
Surgical seeding of chordomas
Authors: Arnautović Kenan I. , Al-Mefty Ossama
Published: May 2009

Object. Chordomas have a high propensity for local recurrence and progression, as well as for systemic and cerebrospinal fluid metastasis. The authors identified and analyzed a series of patients with chordomas, focusing on an underrecognized pathological entity—surgical seeding of tumor cells.

Methods. In a retrospective analysis of 82 patients with chordomas treated over a 10-year period (1990–2000), the authors found six patients (7.3%) in whom surgical seeding had occurred. In five (83%) of these patients the primary tumor was located at the clivus. In one (17%), the tumor was present at the cervical spine. There were two male (33%) and four female patients (67%) whose mean age was 34 years. The seeding sites, which were separate from the primary tumor, were located along the operative route or in the abdomen where fat was removed. The seeding was diagnosed 5 to 15 months (mean 12 months) after surgery. One seeding site was present in five patients, and 17 seeding sites were present in one patient. The involved tissues included mucosa, bone, dura, muscle, and fat. After resection, all seedings were confirmed histologically.

Conclusions. Seeding of chordomas occurs along the operative route and at distant locations where tissue is harvested. Early diagnosis and aggressive surgery are recommended. Based on the results of this study, the authors suggest that surgical techniques, postoperative radiotherapy, neuroradiological follow-up protocol, and even research on chordomas should be reevaluated.
An unusual middle fossa interdural epidermoid tumor
Authors: Inoue Yuichi , Ohata Kenji , Nakayama Keiko , Haba Tomoko , Shakudo Miyuki
Published: May 2009

✓ The authors report an unusual case of an intracranial, interdural epidermoid tumor and cyst in a 72-year-old woman who presented with longstanding, mild numbness over her right cheek. She was initially treated conservatively, but on follow-up review the mass was found to have grown and evidence of hemorrhage was present, and therefore a subtotal resection was performed. This case should probably be classified as a paratrigeminal, interdural epidermoid cyst; this is the first known report in which magnetic resonance and computerized tomography images of such an entity are presented and discussed.
Give neurosurgery a place to stand
Authors: Dunsker Stewart B.
Published: May 2009

✓ In his 2001 Presidential Address to the American Association of Neurological Surgeons, Dr. Dunsker calls on all neurosurgeons to become active participants in the ongoing debates over healthcare. He reviews some history of the debates and points out that regulation of healthcare has been left to bureaucrats—both government and private—physicians, who have intimate knowledge of the field, being excluded. Dr. Dunsker encourages neurosurgeons to volunteer in local, state, and federal medical societies and to join forces with other physicians to gain leverage in the healthcare debate. In this manner it is hoped that better ways of delivering the best healthcare to patients can be accomplished.
Chordomas of the craniocervical junction: follow-up review and prognostic factors
Authors: Colli Benedicto O. , Al-Mefty Ossama
Published: May 2009

Object. Chordomas are rare tumors that arise from the remnants of the notochord. Because of their deep location, local infiltrative nature, and involvement of surrounding bone, treatment of chordomas is a challenge. In this study the authors analyze the data and prognostic factors obtained during the follow-up period (range 1–150 months, median 38 months) in 53 patients with craniocervical junction chordomas and 10 patients with chondrosarcomas.

Methods. Several surgical approaches were used, and some tumor excisions required staged procedures. Survival was calculated according the Kaplan—Meier method. Statistical analysis was performed using Fisher exact, log rank and Kruskal—Wallis tests. Radical/subtotal resection was achieved in 77.8% of the patients. The mortality rate during the follow-up period was 14.3%. In patients harboring chondrosarcoma better 5-year recurrence-free survival (RFS) rates were demonstrated than in those with chordoma (100% and 50.7%, respectively). Histological patterns (typical or chondroid chordomas) and patient age at onset of symptoms had no effect on the RFS rates. Radical/subtotal resections were associated with better RFS rates than partial resection. Adjuvant proton-beam therapy was shown to increase the RFS rates compared with conventional radiotherapy (90.9% and 19.4%, respectively, at 4 years posttreatment). Karyotypically abnormal tumors were associated with the worst RFS rates compared with karyotypically normal lesions (44.5% and 90.3%, respectively, at 3 years). Cases of cranial nerve palsy followed by those with cerebrospinal fluid leakages were the most frequent postoperative complications. Permanent postoperative neurological deficit was observed in 28.6% of the patients.

Conclusions. A better prognosis was observed in patients with chondrosarcoma compared with those harboring chordoma. Histological pattern and patient age at symptom onset were not factors that influenced prognosis in cases of chordoma. Extensive resection and possibly adjuvant proton-beam therapy provided better prognoses for these patients.
Contemporary psychosurgery and a look to the future
Authors: Feldman Robert P. , Alterman Ronald L. , Goodrich James T.
Published: May 2009

Object. Despite a long and controversial history, psychosurgery has persisted as a modern treatment option for some severe, medically intractable psychiatric disorders. The goal of this study was to review the current state of psychosurgery.

Methods. In this review, the definition of psychosurgery, patient selection criteria, and anatomical and physiological rationales for cingulotomy, subcaudate tractotomy, anterior capsulotomy, and limbic leukotomy are discussed. The historical developments, modern procedures, and results of these four contemporary psychosurgical procedures are also reviewed. Examples of recent advances in neuroscience indicating a future role for neurosurgical intervention for psychiatric disease are also mentioned.

Conclusions. A thorough understanding of contemporary psychosurgery will help neurosurgeons and other physicians face the ethical, social, and technical challenges that are sure to lie ahead as modern science continues to unlock the secrets of the mind and brain.
Recording nasal muscle F waves and electromyographic activity of the facial muscles: a comparison of two methods used for intraoperative monitoring of facial nerve function
Authors: Wedekind Christoph , Klug Norfrid
Published: May 2009

Object. A comparison of two electrophysiological methods used to assess facial nerve function intraoperatively was conducted in 33 patients with tumors of the cerebellopontine angle.

Methods. All 33 patients had presented with normal facial nerve function preoperatively. After general anesthesia had been induced by a mixture of midazolam and fentanyl, continual online EMG recordings from the orbicularis oculi and oris muscles were alternated with nasal muscle F-wave recordings. Facial nerve outcomes, assessed using a modified House—Brackmann scale, varied among good (48%), moderate (18%), and poor (33%). Analysis of electromyographic (EMG) data resulted in a significant correlation between the finding of only transient manipulation-evoked activity and a good outcome, whereas in cases in which there was poor outcome, an increase in the amplitude or duration of ongoing activity was detected. A permanent loss of nasal muscle F waves specifically appeared to indicate a severe dysfunction of the facial nerve that was linked to a poor outcome. All patients with latency and/or amplitude changes or even a transient loss of the F wave achieved good or moderate facial nerve outcomes. A transient loss of the F wave, however, was detected significantly more frequently in patients with moderate outcomes. None of these patients exhibited normal facial function (House—Brackmann Grade I) postoperatively.

Conclusions. Online EMG monitoring can provide some information on imminent or even present damage to the facial nerve intraoperatively. The diagnostic sensitivity, specificity, and positive predictive values of a permanent F-wave loss, however, are much higher than those of EMG monitoring. Additionally, this loss of the F wave is supposed to be transient if the surgical procedure is stopped until the F wave recovers. Therefore, F-wave monitoring serves to alert the surgeon that the facial nerve is about to receive a lesion.
Radiosurgery performed with the aid of a 3-mm collimator in the subthalamic nucleus and substantia nigra of the vervet monkey
Authors: De Salles Antonio A. F. , Melega William P. , Laćan Goran , Steele Lisa J. , Solberg Timothy D.
Published: May 2009

Object. Radiosurgery for functional neurosurgery performed using a linear accelerator (LINAC) has not been extensively characterized in preclinical studies. In the present study, the properties of a newly designed 3-mm-diameter collimator were evaluated in a dedicated LINAC, which produced lesions in the basal ganglia of vervet monkeys. Lesion formation was determined in vivo in three animals by examining magnetic resonance (MR) images to show the dosedelivery precision of targeting and the geometry and extent of the lesions. Postmortem immunohistochemical studies were conducted to determine the extent of lesion-induced radiobiological effects.

Methods. In three male vervet monkeys, the subthalamic nucleus (STN; one animal) and the pars compacta of the lateral substantia nigra (SN; two animals) were targeted by a Novalis Shaped Beam Surgery System that included a 3-mm collimator and delivered a maximum dose of 150 Gy. Magnetic resonance images obtained 4, 5, and 9 months posttreatment were reviewed, and the animals were killed so that immunohistological characterizations could be made.

Conclusions. The generation of precise radiosurgical lesions by a 3-mm collimator was validated in studies that targeted the basal ganglia of the vervet monkey. The extent of the lesions created in all animals remained restricted in diameter (< 3 mm) throughout the duration of the studies, as assessed by reviewing MR images. Histological studies showed that the lesions were contained within the STN and SN target areas and that there were persistent increases in glial fibrillary acidic protein immunoreactivity. Increases in immunoreactivity for tyrosine hydroxylase, the serotonin transporter, and the GluR1 subunit of the α-amino-3-hydroxy-5-methyl-4-isoxazole propionate glutamate receptor in penumbral regions of the lesion were suggestive of compensatory neuronal adaptations. This radiosurgical approach may be of particular interest for the induction of lesions of the STN and SN in studies of experimental parkinsonism, as well as for the development of potential radiosurgical treatments for Parkinson disease.
Site-specific immune response to implanted gliomas
Authors: Proescholdt Martin A. , Merrill Marsha J. , Ikejiri Barbara , Walbridge Stuart , Akbasak Aytac , Jacobson Steven , Oldfield Edward H.
Published: May 2009

Object. Immunotherapy for glioblastoma has been uniformly ineffective. The immunological environment of the brain, with its low expression of major histocompatibility complex (MHC) molecules and limited access for inflammatory cells and humoral immune effectors due to the blood—brain barrier (BBB), may contribute to the failure of immunotherapy. The authors hypothesize that brain tumors are protected from immune surveillance by an intact BBB at early stages of development. To investigate the immunological characteristics of early tumor growth, the authors compared the host response to a glioma implanted into the brain and into subcutaneous tissue.

Methods. Samples of tumors growing in the brain or subcutaneously in rats were obtained for 7 consecutive days and were examined immunohistochemically for MHC Class I & II molecules, and for CD4 and CD8 lymphocyte markers. Additionally, B7-1 costimulatory molecule expression and lymphocyte-specific apoptosis were examined.

Conclusions. On Days 3 and 4 after implantation, brain tumors displayed significantly lower MHC Class II expression and lymphocytic infiltration (p < 0.05). After Day 5, however, no differences were detected. The MHC Class II expressing cells within the brain tumors appeared to be infiltrating microglia. Minimal B7-1 expression combined with lymphocyte-specific apoptosis were detected in both brain and subcutaneous tumors. Low MHC Class II expression and low lymphocytic infiltration at early time points indicate the importance of the immunologically privileged status of the brain during early tumor growth. These characteristics disappeared at later time points, possibly because the increasing perturbation of the BBB alters the specific immunological environment of the brain. The lack of B7-1 expression combined with lymphocyte apoptosis indicates clonal anergy of glioma-infiltrating lymphocytes regardless of implantation site.
Choroid plexus carcinoma presenting as an intraparenchymal mass
Authors: Carter Alexis Byrne , Price Donald L. , Tucci Keith A. , Lewis Gregory K. , Mewborne Jeffrey , Singh Harsharan K.
Published: May 2009

✓ A 6-year-old girl with a history of a nondisplaced skull fracture diagnosed with computerized tomography (CT) scanning 3 years previously presented with a 6-week history of headaches and decreased use of her right side. On admission CT scans, a large cystic mass was identified in the left frontal lobe region of the brain. A connection between the mass and the ventricular system was not seen on radiological examination or during surgery. Gross-total resection of the mass was achieved. The histological and immunohistochemical findings in the resected tissue confirmed a diagnosis of choroid plexus carcinoma (ChPC). This is the first reported case of a ChPC arising in an extraventricular location not associated with the choroid plexus.
An MKM-mounted instrument holder for frameless point-stereotactic procedures: a phantom-based accuracy evaluation
Authors: Willems Peter W. A. , Noordmans Herke Jan , van der Sprenkel Jan Willem Berkelbach , Viergever Max A. , Tulleken Cees A. F.
Published: May 2009

✓ To enable the use of the Mehrkoordinaten Manipulator (MKM) robotic navigation system for frameless point stereotactic procedures, a new instrument holder is presented. A phantom-based accuracy study was performed in which this new method was compared with frame-based procedures performed using the Brown-Roberts-Wells (BRW) stereotactic frame.

The authors acquired computerized tomography scans of a test phantom, consisting of 19 acrylic plastic target rods on a circular base. These images were used in frame-based (BRW) and frameless (MKM) localization experiments. In both cases the authors calculated the distances between the actual target positions and the positions reached stereotactically.

The mean application accuracy (target registration error) was 0.68 mm when the BRW frame was used and 0.96 mm when the MKM system was used after manual repositioning of the microscope (p < 0.001). Positioning accomplished using robotics only demonstrated a slightly larger inaccuracy: 1.47 mm (p < 0.005). Because the surgeon is concerned with the largest error in an individual case rather than the mean error in a large number of cases, the mean + three standard deviations was also compared. This value differed very little between the manually positioned MKM system and the BRW frame (2.04 mm and 1.84 mm, respectively). Although repeatability per target appeared to be slightly better when the BRW frame was used, accuracy was more homogeneous over the phantom volume when the MKM system was used (both differences were not significant).

In conclusion, the accuracy of point stereotactic procedures performed using an instrument holder attached to the MKM system is comparable with the accuracy of procedures involving a stereotactic frame. Moreover, the frameless techniques and robotic features of the MKM enable a more surgeon- and patient-friendly stereotactic procedure.
Prevalence of asymptomatic incidental aneurysms: review of 4568 arteriograms
Authors: Winn H. Richard , Jane John A. , Taylor James , Kaiser Donald , Britz Gavin W.
Published: May 2009

Object. The prevalence of unruptured cerebral aneurysms is unknown, but is estimated to be as high as 5%. The goal of this study was to determine the prevalence of asymptomatic incidental aneurysms.

Methods. The authors studied all cerebral arteriography reports produced at a single institution, the University of Virginia, between April 1969 and January 1980. A review of 3684 arteriograms demonstrated 24 cases of asymptomatic aneurysms, yielding a prevalence rate of 0.65%. The majority (67%) of the 24 patients harboring unruptured aneurysms were women. More than 90% of the unruptured aneurysms were located in the anterior circulation and in locations similar to those found in patients with ruptured aneurysms. Nearly 80% of the aneurysms were smaller than 1 cm in their greatest diameter. The frequency of asymmetrical unruptured aneurysms (0.6–1.5%) was constant throughout all relevant age ranges (35–84 years).

Conclusions. While keeping in mind appropriate caveats in extrapolating from these data, the prevalence rate of asymptomatic unruptured aneurysms found in the present study allows an estimation of the yearly rate of rupture of these lesions. The authors suggest that this yearly rate of rupture falls within the range of 1 to 2%.
Multiplicity of dural arteriovenous fistulas
Authors: Van Dijk J. Marc C. , TerBrugge Karel G. , Willinsky Robert A. , Wallace M. Christopher
Published: May 2009

Object. Dural arteriovenous fistulas (AVFs) are a well-known pathoanatomical and clinical entity. Excluding bilateral involvement of the cavernous sinus, multiple dural AVFs are rare, with isolated reports in the literature. The additional risk associated with multiplicity is unknown, although it has been claimed that there is a greater risk of hemorrhage at presentation. In a group of 284 patients with dural AVFs consecutively treated at a single center, the occurrence of multiplicity is investigated and its risk factors for hemorrhage are identified.

Methods. Among the 284 patients with both cranial and spinal dural AVFs, 20 patients with multiple fistulas were found. Nineteen (8.1%) of 235 patients with cranial AVFs had multiple cranial fistulas, and one (2%) of 49 patients with spinal AVFs harbored two spinal fistulas. Twelve patients were found to have a lesion at two separate sites, seven patients had them at three locations, and one patient had four fistulas, each at a different site.

In the subgroup with multiple AVFs the percentage of hemorrhage at presentation was three times higher than in the entire group (p = 0.01). Cortical venous drainage in cranial fistulas was present in 84% of patients with multiple lesions compared with 46% of patients with solitary lesions (p < 0.005).

Conclusions. Multiple dural AVFs are not rare. In this group of 284 patients it was found in 8.1% of all patients with cranial dural AVFs. Multiplicity was associated with a higher percentage of cortical venous drainage, a pattern of drainage reportedly yielding a higher risk for hemorrhage.
Comparative study of traumatic and spontaneous intracerebral hemorrhage
Authors: Siddique M. Shahid , Gregson Barbara A. , Fernandes Helen M. , Barnes Jane , Treadwell Lynne , Wooldridge Thomas D. , Mendelow A. David
Published: May 2009

Object. Spontaneous intracerebral hemorrhage (SICH) and traumatic intracerebral hemorrhage (TICH) are common disorders. The authors planned to study how these two types of hemorrhage behave pathologically and clinically to gain further insight into their causes, pathogeneses, indications for surgical intervention, and prognoses.

Methods. Prospectively filled databases of demographic, clinical, radiological, and outcome details have been maintained for all patients admitted to the Regional Neurosciences Centre with head injury since 1987 and with SICH since 1993. Of the 5686 patients whose case information was included in the head-injury database, 90 were found to suffer from an isolated intracerebral hemorrhage (ICH) as the only major abnormality observed on computerized tomography scans (subdural and extradural hematomas were excluded). Case details on these 90 patients and the 440 patients from the SICH database were extracted and analyzed using a statistical software program.

The median age of patients with TICH was lower than the median age of patients with SICH (51 years compared with 65 years, respectively), but it was much higher than the median age of the entire head-injury group (21 years). Among patients younger than 45 years of age, 0.8% of patients who experienced trauma suffered from an ICH compared with 4.3% of patients older than 45 years of age. Irrespective of intervention, much better outcomes were achieved by patients with TICH compared with those with SICH (67% favorable outcomes compared with 24% in patients with SICH). Following trauma, there was no significant relationship between the severity of injury and the development of ICH. At presentation the median Glasgow Coma Scale (GCS) score for both groups was 13. Younger age and higher GCS score at presentation were strongly related to a favorable outcome for both types of hemorrhage. There was no significant difference in patient age, presenting GCS score, or outcomes of patients who underwent surgery compared with those who did not for either type of hemorrhage. No conclusions can be drawn about the efficacy of surgery from such observational studies.

Conclusions. On the basis of these data the authors suggest that TICH and SICH have different features: TICH affects a slightly younger age group and carries a much better prognosis compared with SICH. In addition, indications for surgical intervention are not well defined for either type of hemorrhage. Practice is subjective and inconsistent. The International Surgical Trial in Intracerebral Haemorrhage may resolve the dilemma for SICH. A similar trial in which surgery is compared with conservative management should be considered for cases of TICH.