bluuebunny/crossref_metadata_2025 huggingface dataset:
Chordoma of the skull base: predictors of tumor recurrence
Authors: Pallini Roberto , Maira Giulio , Pierconti Francesco , Falchetti Maria Laura , Alvino Ester , Cimino-Reale Graziella , Fernandez Eduardo , D'Ambrosio Ettore , Larocca Luigi Maria
Published: May 2009

Object. Chordomas of the skull base are generally regarded as slow-growing tumors; however, approximately 20% of these lesions have been shown to recur as early as 1 year postsurgery. The classic pathological paradigms are poor predictors of outcome, and additional markers are needed to identify patients at risk for early tumor recurrence. In this study the authors describe such a marker.

Methods. In a series of 26 patients with chordomas of the skull base, the authors investigated the relationship between the biological behavior of the tumor, which was determined according to the interval for its recurrence and volume doubling time, and several pathological and molecular features, which included the histological variant, proliferative activity, mutation of p53 protein, expression of human telomerase reverse transcriptase (hTERT) messenger (m)RNA, loss of heterozygosity (LOH), and microsatellite instability. The major finding in this study was that hTERT mRNA expression in chordoma cells identifies those tumors that exhibit unusually fast rates of growth. The expression of hTERT mRNA was frequently associated with mutation of p53 protein, indicating that telomerase dysfunction combines with abnormal p53 function to initiate the unrestrained clonal expansion of the tumor cells. In cases in which the tumor was partially removed, mutation of p53 protein and expression of hTERT mRNA predicted increased doubling time for residual tumor as well as the probability of tumor recurrence. Cell proliferation, as investigated using the Ki-67 method, was significantly related to the tumor doubling time; however, the authors found that the pattern of cell proliferation was not homogeneous throughout the chordoma tissue, and that the proliferative index might change by a factor as high as 8 among different regions of the same tumor. The LOH and microsatellite instability do not seem to affect the prognosis of skull base chordomas.

Conclusions. Reactivation of telomerase in chordomas is a reliable predictor of outcome. The ability to predict the biological behavior of chordomas might have immediate implications in the management of this disease in patients who undergo surgery.
Microvascular pathological features of immediate perinidal parenchyma in cerebral arteriovenous malformations: giant bed capillaries
Authors: Attia Walid , Tada Tsuyoshi , Hongo Kazuhiro , Nagashima Hisashi , Takemae Toshiki , Tanaka Yuichiro , Kobayashi Shigeaki
Published: May 2009

Object. The behavior of brain tissue in cases of arteriovenous malformations (AVMs) is a matter of debate. The authors believe that the local microvascular environment in the AVM bed shares the hemodynamic changes influencing that behavior in one way or another. The purpose of this study was to investigate the microvascular pathological features in the immediate perinidal brain tissue.

Methods. This retrospective study was conducted using excised AVM specimens obtained in 35 patients, from which the authors selected 20 specimens that fulfilled the criteria for sufficient brain tissue around the excised nidus. Specimens were stained with hematoxylin and eosin, and the immediate perinidal microvascular environment was examined using light microscopy.

Conclusions. Eighty-five percent of the AVMs studied showed the presence of huge, dilated capillaries, and 65% showed severe congestion of these capillaries. The authors have named these capillaries “giant bed capillaries.” In this study capillary bleeding was shown in AVMs, and a pericapillary space was seen around some vessels. The brain parenchyma containing AVMs with these findings proved to be significantly ischemic.
Communication between malignant glioma cells and vascular endothelial cells through gap junctions
Authors: Zhang Wei , DeMattia Joseph A. , Song Hua , Couldwell William T.
Published: May 2009

Object. Extensive invasion and angiogenesis are hallmark features of malignant gliomas. Communication between malignant glioma cells and surrounding astrocytes occurs, resulting in transformation of the astrocytic phenotype. In the present study, the authors examined whether malignant glioma cells and vascular endothelial cells (VECs) communicate through the formation of gap junctions and whether this communication influences angiogenesis.

Methods. Connexin43 (Cx43), a gap junction protein expressed in glioma cells, was identified in human umbilical VECs (HUVECs). Immunocytochemical staining for Cx43 demonstrated immunoreactive plaques at areas of cell—cell contact among HUVECs as well as between HUVECs and Cx43-expressing malignant glioma cells. Dye transfer, performed using the gap junction—permeable dye dicarboxy-dichlorofluorescein diacetate (CDCF), among these cocultures indicated that these were functional communications. Calcium signaling also occurred from malignant glioma cells to HUVECs. Tube formation by HUVECs cocultured with Cx43-transfected T98G malignant glioma cells (T98G-Cx43 cells) or with U87MG malignant glioma cells, which naturally express Cx43, was significantly increased compared with tube formation by HUVECs alone. The difference in tube formation by HUVECs cocultured with empty vector—transfected T98G glioma cells (T98G-mock cells) or with Cx43-deficient U373MG malignant glioma cells and tube formation by HUVECs alone was not statistically significant. Furthermore, the concentration of vascular endothelial growth factor (VEGF), an angiogenic factor important for the induction of angiogenesis and blood vessel formation, was significantly higher in medium harvested from cultures of T98G-Cx43 cells than in that harvested from cultures of control T98G-mock cells. Human malignant glioma U87MG cells also secreted increased concentrations of VEGF as compared with HUVECs alone. Nevertheless, there was no statistically significant difference in tube formation by HUVECs cultured in medium conditioned by either Cx43-expressing or Cx43-deficient glioma cells, suggesting that the direct gap junction communication between glioma cells and HUVECs may play a much more significant role than the increased VEGF secretion in vascular tube formation in this assay.

Conclusions. These results indicate that functional gap junction formation between human malignant glioma cells and VECs occurs. This communication appears to influence tumor angiogenesis. Targeting gap junction signaling may offer a potential mechanism for therapy in patients with these tumors.
High-dose ibuprofen for reduction of striatal infarcts during middle cerebral artery occlusion in rats
Authors: Antezana David F. , Clatterbuck Richard E. , Alkayed Nabil J. , Murphy Stephanie J. , Anderson Lauren G. , Frazier James , Hurn Patricia D. , Traystman Richard J. , Tamargo Rafael J.
Published: May 2009

Object. Ibuprofen is an antiinflammatory drug that disrupts leukocyte—endothelial cell interactions by limiting expression of endothelial adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1), also known as CD54. The authors hypothesized that ibuprofen could reduce the size of the infarct associated with transient focal ischemia by inhibition of ICAM-1 expression, and they evaluated its effects in rats treated with middle cerebral artery (MCA) occlusion. Ibuprofen treatment was compared with mild systemic hypothermia, which is known to be neuroprotective and is commonly used during neurosurgical procedures.

Methods. The maximum ibuprofen dose (240 mg/kg/day) that could be tolerated with no systemic toxicity was established in the initial experiments. In the efficacy experiment, rats were pretreated with vehicle, ibuprofen, or hypothermia (33°C) prior to 2 hours of MCA occlusion; then their brains were harvested at 24 hours of reperfusion for histological studies. End-ischemic cerebral blood flow (CBF) was evaluated using [14C]iodoantipyrine autoradiography in additional cohorts. Expression of ICAM-1 within ischemic compared with nonischemic caudate nucleus and putamen (striatum) or cortex was evaluated using immunohistochemical studies. Compared with vehicle treatment, ibuprofen produced a 46.2% reduction (p = 0.01) in striatal infarcts, which was comparable to hypothermia (48.7% reduction, p = 0.02). Ibuprofen did not alter end-ischemic CBF in any region studied, and the ibuprofen treatment group had the lowest proportion of animals with marked ICAM-1 staining.

Conclusions. Ibuprofen given in maximum tolerated doses reduces the striatal infarct size after focal cerebral ischemia. The neuroprotective mechanism does not work through preservation of intraischemic CBF and is consistent with inhibition of ICAM-1 expression; however, at the doses used in this study, other effects of ibuprofen on platelet and endothelial function are possible.
Juxtaposition of an ectopic corticotroph adenoma of the sphenoid sinus with orthotopic intrasellar corticotroph hyperplasia in a patient with Cushing disease
Authors: Al-Gahtany Mubarak , Bilbao Juan , Kovacs Kalman , Horvath Eva , Smyth Harley S.
Published: May 2009

✓ Ectopic pituitary adenomas (EPAs) are rare and their association with orthotopic corticotroph hyperplasia has not been published.

The case of a 30-year-old woman with clinical and biochemical evidence of Cushing disease (CD) is reported. A magnetic resonance image obtained preoperatively revealed asymmetrical inhomogeneity of the pituitary gland, which was suggestive of localized adenoma. It also showed what was thought to be a small sphenoid polyp. Postoperatively the latter lesion was found to be an ectopic corticotroph adenoma. The pituitary gland, which was free from any tumor, exhibited diffuse unilateral corticotroph hyperplasia. Clinical, radiological, laboratory, and histopathological findings are presented. A review of the literature and a discussion of possible causes of this unique association between the ectopic corticotroph adenoma and the pituitary hyperplasia are provided.
Broadening the clinical spectrum: unusual presentation of spontaneous cerebrospinal fluid hypovolemia
Authors: Nowak Dennis A. , Rodiek Sven-Olaf , Zinner Jürgen , Guhlmann Albrecht , Topka Helge
Published: May 2009

✓ The syndrome of spontaneous intracranial hypotension is characterized by orthostatic headaches in conjunction with reduced cerebrospinal fluid (CSF) pressure or CSF volume, and characteristic magnetic resonance (MR) imaging findings.

A 50-year-old man presented with a 1-year history of paroxysmal ataxia of gait and short attacks of blurred vision when he stood up from a recumbent position and began to walk. Orthostatic headache was not a feature of his clinical presentation. Magnetic resonance images of the brain revealed diffuse enhancement of the dura mater and hygromas over both cerebral convexities. Magnetic resonance images of the spine demonstrated dilated cervical epidural veins and dilation of the perimedullary veins. Radionuclide cisternography identified a CSF leakage that was localized to the T12—L1 level on subsequent myelograms and on computerized tomography scans obtained after the myelograms. An epidural blood patch was administered and visualized with tungsten powder. The patient's clinical symptoms and sites of disease on imaging completely resolved.

The unusual clinical presentation in this case—paroxysmal ataxia of gait, lack of orthostatic headaches, and dilated epidural and perimedullary venous plexus—supports a recently noted broadening of both the clinical and imaging characteristics of spontaneous intracranial hypovolemia.
Transposition of the oculomotor nerve for resection of a midbrain cavernoma
Authors: Takami Toshihiro , Ohata Kenji , Nishikawa Misao , Goto Takeo , Terakawa Yuzo , Inoue Yuichi , Wakasa Kenichi , Hara Mitsuhiro
Published: May 2009

✓ The authors discuss the utility of anterior transposition of the oculomotor nerve from the lateral wall of the cavernous sinus to widen the corridor posterior to the cisternal segment of the oculomotor nerve; this allows exposure of the anterolateral surface of the midbrain. This additional exposure was successfully used for the resection of a large calcified cavernoma in the upper brainstem of a 67-year-old woman who had presented with sudden onset of left hemiparesis and oculomotor palsy. The patient's postoperative course was uneventful and she displayed symptomatic improvement.
Transaqueductal aspiration of pontine hemorrhage with the aid of a neuroendoscope
Authors: Takimoto Hiroshi , Iwaisako Kousuke , Kubo Shigeki , Yamanaka Kazunori , Karasawa Jun , Yoshimine Toshiki
Published: May 2009

✓ The authors advocate the use of a 1.7-mm fiberscope to evaluate a hypertensive bilateral tegmental pontine hemorrhage that has ruptured, in part, into the fourth ventricle. In applying this new technique, a fiberscope, which contains a guide tube in the working channel, is inserted into the aqueduct. After the endoscope has been removed, a silicone tube is slid along the guide tube. The hematoma is evacuated through the silicone tube and a potassium titanyl phosphate laser is used to achieve hemostasis.
Frameless image-guided stereotactic biopsy of parasellar lesions
Authors: Frighetto Leonardo , De Salles Antonio A. F. , Behnke Eric , Smith Zachary A. , Chute Dennis
Published: May 2009

✓ Interactive image-guided neuronavigation was used to obtain biopsy specimens of cavernous sinus (CS) tumors via the foramen ovale. In this study the authors demonstrated a minimally invasive approach in the management of these lesions.

In four patients, whose ages ranged from 29 to 89 years (mean 61.2 years) and who harbored undefined lesions invading the CS, neuronavigation was used to perform frameless stereotactic fine-needle biopsy sampling through the foramen ovale. The biopsy site was confirmed on postoperative computerized tomography scanning.

The frameless technique was accurate in displaying a real-time trajectory of the biopsy needle throughout the procedure. The lesions within the CS were approached precisely and safely. Diagnostic tissue was obtained in all cases and treatment was administered with the aid of stereotactic radiosurgery or fractionated stereotactic radiotherapy. The patients were discharged after an overnight stay with no complications.

Neuronavigation is a precise and useful tool for image-guided biopsy sampling of CS tumors via the foramen ovale.
Surgical outcomes of 654 ulnar nerve lesions
Authors: Kim Daniel H. , Han Kisoo , Tiel Robert L. , Murovic Judith A. , Kline David G.
Published: May 2009

Object. In this article the authors present a retrospective analysis of 654 surgical outcomes in patients with ulnar nerve entrapments, injuries, and tumors during a 30-year period.

Methods. Data were gathered between 1968 and 1998 at Louisiana State University Health Sciences Center. Mechanisms of injuries or lesions included 460 entrapments at the elbow level (70%), 76 lacerations (12%), 52 stretches/contusions (8%), 34 fractures/dislocations (5%), 12 gunshot wounds (2%), two injection-induced injuries (0.3%), and 13 nerve sheath tumors (2%).

In cases of entrapment, direct operative recordings uniformly demonstrated a slowing of conduction at the elbow, even in cases in which preoperative noninvasive studies had been nondiagnostic. Intraoperative electrical “inching” studies also demonstrated significant conduction abnormalities that lie just proximal to and through the olecranon notch rather than distal, beneath the flexor carpi ulnaris muscle. There were only eight exceptions to this. Lesions not in continuity due to the injury required primary or secondary end-to-end sutures or graft repair. Aided by intraoperative nerve action potential recording, lesions in continuity received either external or internal neurolysis and split repair or resection followed by end-to-end suture or graft repair. Functional recoveries of Grade 3 or better were seen in 81 (92%) of 88 patients who underwent neurolysis, 42 (72%) of 58 patients who received suture repair, and 24 (67%) of 36 patients who received graft repair. Nevertheless, fewer Grade 4 or 5 recoveries were reached than those seen in patients with radial or median nerve injuries. Nerve sheath tumors were resected with preservation of preoperative function in five of seven patients.

Conclusions. Although difficult to obtain, useful functional recovery can be achieved with proper surgical management of ulnar nerve entrapments and injuries.
Complications of invasive subdural grid monitoring in children with epilepsy
Authors: Önal Çagatay , Otsubo Hiroshi , Araki Takashi , Chitoku Shiro , Ochi Ayako , Weiss Shelly , Logan William , Elliott Irene , Snead O. Carter , Rutka James T.
Published: May 2009

Object. This study was performed to evaluate the complications of invasive subdural grid monitoring during epilepsy surgery in children.

Methods. The authors retrospectively reviewed the records of 35 consecutive children with intractable localization-related epilepsy who underwent invasive video electroencephalography (EEG) with subdural grid electrodes at The Hospital for Sick Children between 1996 and 2001. After subdural grid monitoring and identification of the epileptic regions, cortical excisions and/or multiple subpial transections (MSTs) were performed. Complications after these procedures were then categorized as either surgical or neurological.

There were 17 male and 18 female patients whose mean age was 11.7 years. The duration of epilepsy before surgery ranged from 2 to 17 years (mean 8.3 years). Fifteen children (43%) had previously undergone surgical procedures for epilepsy. The number of electrodes on the grids ranged from 40 to 117 (mean 95). During invasive video EEG, cerebrospinal fluid leaks occurred in seven patients. Also, cerebral edema (five patients), subdural hematoma (five patients), and intracerebral hematoma (three patients) were observed on postprocedural imaging studies but did not require surgical intervention. Hypertrophic scars on the scalp were observed in nine patients. There were three infections, including one case of osteomyelitis and two superficial wound infections. Blood loss and the amounts of subsequent transfusions correlated directly with the size and number of electrodes on the grids (p < 0.001). Twenty-eight children derived significant benefit from cortical resections and MSTs, with a more than 50% reduction of seizures and a mean follow-up period of 30 months.

Conclusions. The results of this study indicate that carefully selected pediatric patients with intractable epilepsy can benefit from subdural invasive monitoring procedures that entail definite but acceptable risks.
Pseudotumor cerebri syndrome: venous sinus obstruction and its treatment with stent placement
Authors: Owler Brian K. , Parker Geoffrey , Halmagyi G. Michael , Dunne Victoria G. , Grinnell Verity , McDowell David , Besser Michael
Published: May 2009

Object. Pseudotumor cerebri, or benign intracranial hypertension, is a condition of raised intracranial pressure in the absence of a mass lesion or cerebral edema. It is characterized by headache and visual deterioration that may culminate in blindness. Pseudotumor cerebri is caused by venous sinus obstruction in an unknown percentage of cases. The purpose of this study was to investigate the role of cerebral venous sinus disease in pseudotumor cerebri and the potential of endoluminal venous sinus stent placement as a new treatment.

Methods. Nine consecutive patients in whom diagnoses of pseudotumor cerebri had been made underwent examination with direct retrograde cerebral venography (DRCV) and manometry to characterize the morphological features and venous pressures in their cerebral venous sinuses. The cerebrospinal fluid (CSF) pressure was measured simultaneously in two patients. If patients had an amenable lesion they were treated using an endoluminal venous sinus stent. Five patients demonstrated morphological obstruction of the venous transverse sinuses (TSs). All lesions were associated with a distinct pressure gradient and raised proximal venous sinus pressures. Four patients underwent stent insertion in the venous sinuses and reported that their headaches improved immediately after the procedure and remained so at 6 months. Vision was improved in three patients, whereas it remained poor in one despite normalized CSF pressures.

Conclusions. Patients with pseudotumor cerebri should be evaluated with DRCV and manometry because venous TS obstruction is probably more common than is currently appreciated. In patients with a lesion of the venous sinuses, treatment with an endoluminal venous sinus stent is a viable alternative for amenable lesions.
Polysialylated neural cell adhesion molecules expressed in human pituitary tumors and related to extrasellar invasion
Authors: Trouillas Jacqueline , Daniel Laurent , Guigard Marie-Paule , Tong Soutsakhone , Gouvernet Joanny , Jouanneau Emmanuel , Jan Michel , Perrin Gilles , Fischer Georges , Tabarin Antoine , Rougon Geneviève , Figarella-Branger Dominique
Published: May 2009

Object. Pituitary adenomas are usually benign tumors; however, some behave aggressively and metastasize. Until now, no specific marker of aggressive behavior or malignancy has been found. The polysialylated neural cell adhesion molecule (NCAM), which is highly expressed in embryonic tissues such as the brain and pituitary, is detected in some neuronal and neuroendocrine tumors. Because polysialylation has been implicated in the regulation of cell growth and migration, polysialylated NCAM expression has been considered as a prognostic marker in such tumors.

Methods. In the present study, the authors analyzed polysialylated NCAM expression in 82 pituitary tumors from humans: 49 secreting adenomas, 32 nonfunctioning adenomas, and one growth hormone and prolactin—secreting carcinoma associated with acromegaly and spinal and liver metastases. Based on immunohistochemical analyses, the tumors were classified as somatotropic (22 tumors), prolactinoma (14 tumors), corticotropic (17 tumors), and gonadotropic or so-called null cell adenomas (28 tumors). Assessment of polysialylated NCAM was performed using three different methods (immunohistochemical analysis, Western blot analysis, and enzyme-linked immunosorbent assay) with a specific mouse monoclonal immunoglobulin M (Men B) that recognizes polysialic acid on NCAM. Tumoral NCAM expression was also evaluated with the aid of immunohistochemical analysis. Using this method, NCAM and polysialylated NCAM were studied in six healthy pituitaries. In addition, corrrelations were investigated using three statistical methods (chi-square test, nonparametric Mann—Whitney U-test, and principal component analysis) to compare tumoral polysialylated NCAM expression and seven parameters (tumor size and type, intrasphenoidal or cavernous sinus invasion, Ki-67 index, mitoses, and patient age and sex).

Neural cell adhesion molecules were expressed in the healthy anterior pituitary and in all tumors. In contrast, polysialylated NCAM was not found in the healthy pituitary gland, but was expressed in 46.3% of typical pituitary tumors and in 85% of the tumors selected as highly aggressive, including one carcinoma and three tumors with histological characteristics that raised suspicion of malignancy. There was no significant correlation between polysialylated NCAM expression and tumor size, tumor type, Ki-67 index, mitoses, or patient age and sex. In contrast, the expression of polysialylated NCAM, which was sensitive to endoneuraminidase-N treatment, was strongly correlated with tumor invasion (p < 0.0001).

Conclusions. In pituitary tumors in humans, expression of polysialylated NCAM is strongly related to tumor invasion and confirms the clinical diagnosis of aggressiveness.
Intracranial stent placement for the treatment of a carotid—cavernous fistula associated with intracranial angioplasty
Authors: Kim Stanley H. , Qureshi Adnan I. , Boulos Alan S. , Bendok Bernard R. , Levy Elad I. , Yahia Abutaher M. , Guterman Lee R. , Hopkins L. Nelson
Published: May 2009

✓ The authors report a case of an iatrogenic carotid—cavernous fistula (CCF) associated with intracranial angioplasty. Angioplasty was performed using a 3 × 10-mm Open Sail coronary balloon in a patient with high-grade stenosis of the left cavernous internal carotid artery (ICA). After angioplasty, a perforation developed in the cavernous ICA, resulting in a CCF. A 3.5 × 9—mm S670 coronary stent was used to treat the fistula. To the authors' knowledge, this is the first reported case in which a CCF developed after angioplasty was performed using a coronary balloon. Long-term angiographic and clinical evaluation is needed to test the suitability and durability of intracranial angioplasty and stent placement in the treatment of symptomatic intracranial stenosis.
Synchronous subarachnoid drop metastases from a pituitary adenoma with multiple recurrences
Authors: Lehman Norman L. , Horoupian Dikran S. , Harsh Griffith R.
Published: May 2009

✓ The authors report the case of a 49-year-old man with synchronous drop metastases from a multiply recurrent somatotroph pituitary adenoma. The metastatic lesions were found in the subarachnoid space of the cauda equina and foramen magnum 18 years after the initial diagnosis of the disease. Five transsphenoidal resections had previously failed to cure the sellar tumor. Two of these, performed 4 and 5 years before the patient's current presentation, had been complicated by cerebrospinal fluid rhinorrhea that necessitated lumbar drainage. Resections of the two subarachnoid lesions, separated by 14 months, removed pathologically aggressive pituitary adenomas. There were no signs of local recurrence or subarachnoid dissemination of disease during the postoperative follow-up periods, which lasted 18 and 4 months, respectively. Previous cases of subarachnoid spread of a pituitary adenoma have been associated with multiple intracranial metastases, multiple intraspinal metastases, or widely disseminated disease. This case demonstrates that subarachnoid metastasis of a pituitary adenoma, particularly when it follows multiple operations, is not invariably widely disseminated or associated with a very poor prognosis.
A syndrome of spontaneous cerebral and cervical artery dissections with angiolipomatosis
Authors: Schievink Wouter I. , Thompson Reid C. , Yong William H.
Published: May 2009

✓ A primary or systemic arteriopathy is frequently suspected in patients with spontaneous cerebral or cervical artery dissections. The authors report on two patients with such dissections accompanied by angiolipomatosis, a previously unreported association, and propose a common developmental defect in these patients.

A 50-year-old man with subcutaneous angiolipomatosis developed painful monocular blindness. Angiography studies revealed a spontaneous extracranial internal carotid artery (ICA) dissection and an ipsilateral fusiform intracranial ICA aneurysm. The ICA dissection was treated with aspirin, and after 6 months a craniotomy was performed. The aneurysm was found to be fusiform; it involved the entire supraclinoid portion of the ICA, and was wrapped with cotton. A 49-year-old man with a congenitally bicuspid aortic valve and subcutaneous angiolipomatosis developed posterior neck pain. Magnetic resonance imaging and angiography demonstrated a fusiform distal vertebral artery aneurysm. A craniotomy was performed and the aneurysm was found to incorporate the posterior inferior cerebellar artery as well as a perforating artery; the lesion was wrapped with cotton.

The tunica media of the arteries of the head and neck as well as the aortic valvular cusps are derived from neural crest cells, and angiolipomatosis has been associated with tumors of neural crest derivation. These associations indicate that a neural crest disorder may be the underlying abnormality in these patients.
Peripheral nerve surgery and neurosurgeons: results of a national survey of practice patterns and attitudes
Authors: Maniker Allen , Passannante Marian
Published: May 2009

Object. The goal of this study was to determine current practice patterns and attitudes of neurosurgeons toward peripheral nerve surgery.

Methods. A 13-question survey was mailed to all active members of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons. Collected responses were entered into a database and were analyzed using statistical software.

Conclusions. Of 3800 surveys mailed there were 1728 responses for a 45% response rate. Analysis of the data revealed that respondents had a greater comfort level with simple peripheral nerve procedures, such as carpal tunnel release, and a lack of comfort with more complex peripheral nerve procedures, such as brachial plexus exploration. The majority of simple cases were treated by the surveyed neurosurgeons, whereas the majority of complex cases were referred to other surgeons, primarily to other neurosurgeons. The type of medical practice (academic, group, or solo) and the location of the practice (major city, small city, suburban setting, or rural area) showed a statistically significant correlation to simple case referral patterns, whereas the length of time since the respondent underwent training did not. Practice type and location, and years since training showed a statistically significant correlation to complex case referral patterns. Only 48.7% of the respondents believed that they had been given sufficient exposure to peripheral nerve surgery during residency training. The overwhelming majority (97.2%) of respondents favored keeping peripheral nerve surgery as part of the neurosurgical curriculum.
Clinical and neuroimaging characteristics of hydrocephalus associated with vestibular schwannoma
Authors: Tanaka Yuichiro , Kobayashi Shigeaki , Hongo Kazuhiro , Tada Tsuyoshi , Sato Atsushi , Takasuna Hiroshi
Published: May 2009

Object. The clinical and neuroimaging characteristics of hydrocephalus associated with vestibular schwannoma were retrospectively analyzed to improve the perioperative management of the circulation of cerebrospinal fluid.

Methods. A retrospective analysis was performed in 236 patients with unilateral vestibular schwannomas. The patients' ages ranged from 17 to 83 years (mean 53.6 ± 13.2 years), and the diameters of the tumors the patients harbored ranged from 5 to 60 mm (mean 30.5 ± 12.7 mm). Hydrocephalus was present before tumor resection in 33 patients (14%) and in six of these patients focal dilation of the sylvian fissures was noted. There was a significant correlation between the incidence of hydrocephalus and tumor size. The incidence of preoperative hydrocephalus among elderly patients (≥ 65 years of age) was 28.6% and that among younger patients (< 65 years of age) was 10.8%. Tumors in elderly patients with hydrocephalus (mean tumor diameter 32.8 ±11.7 mm; 12 patients) were significantly smaller than those in younger patients (mean tumor diameter 41.7 ± 10.9 mm; 21 patients). Among patients with tumors smaller than 30 mm (114 patients), the incidence of hydrocephalus in elderly patients (25%) was 12-fold higher than that in younger patients (2.1%). Six patients with hydrocephalus who had focal dilation of the sylvian fissures were significantly older than 27 patients with hydrocephalus in whom there was no focal dilation. The dilated sylvian fissures collapsed in two patients spontaneously after tumor resection and in the other four patients after shunt placement.

Conclusions. The incidence of associated hydrocephalus is higher in older patients. Communicating hydrocephalus tends to occur in elderly patients. Enlargement of the ventricles with focal dilation of the sylvian fissures should not be misinterpreted as physiological brain atrophy.
Effect of the local anesthetic agent bupivacaine prior to application of the skull-pin holder for craniotomies
Authors: Mathieu David , Beaudry Mathieu , Martin René , McLelland Hans , Robert Bruno , Kenny Brendan
Published: May 2009

Object. The authors conducted a double-blind prospective randomized study to determine whether infiltration of Mayfield skull-pin sites with 0.5% bupivacaine, compared with placebo, would prevent hemodynamic stimulation, thus allowing for a reduction in the quantity of anesthetic agents required.

Methods. Thirty patients were randomized into two groups. There was a significant increase in blood pressure (mean systolic blood pressure 10 mm Hg, p = 0.003) in patients in the placebo group compared with that in patients in the bupivacaine group 1 minute after securing the head holder.

Conclusions. The local administration of bupivacaine for anesthetic purposes before skull-pin application may prevent potentially hazardous hemodynamic stimulation.
Clinical application of a physically and chemically processed human substitute for dura mater
Authors: Dufrane Denis , Marchal Christophe , Cornu Olivier , Raftopoulos Christian , Delloye Christian
Published: May 2009

Object. Allogenic human fascia lata used in neurosurgery as a dura mater substitute can be associated with the risk of virus and bacterium transmission and with a delay in its incorporation due to immunological and inflammatory reactions. The authors review their preliminary experience with a chemically and physically processed fascia lata graft.

Methods. Grafts that had been treated with solvent detergents, freeze-dried for conservation, and gamma irradiated (25,000 Gy) for sterilization were placed into 17 patients during neurosurgical procedures performed to treat brain tumors, cerebral malformations, trigeminal neuralgia, and posttraumatic lesions. The handling properties of the material, surgical wound features, and hematological parameters were evaluated. The average follow-up period was 23.8 ± 2.2 months (mean ± standard deviation). The handling properties and biocompatibility of these human dural substitutes were highly satisfactory and no major complications were observed. Postoperative computerized tomography or magnetic resonance images obtained in 13 patients revealed no abnormal findings at the site of fascia lata implantation. In one patient who underwent a second surgery performed 12 months after the initial operation, this dural substitute was found to have been recolonized by host fibroblastic cells and replaced by autologous collagenous tissue.

Conclusions. Human fascia lata that has been rendered safe by applying physical and chemical treatment is a fully biocompatible alternative to the dural graft materials currently available.
The efficacy and safety of aprotinin for hemostasis during intracranial surgery
Authors: Palmer James D. , Francis John L. , Pickard John D. , Iannotti Fausto
Published: May 2009

Object. The aim of this study was to determine the safety and efficacy of prophylactic high-dose intravenous aprotinin in reducing intraoperative blood loss in the neurosurgical population.

Methods. A randomized, double-blind, placebo-controlled trial was conducted in parallel groups in two regional neurosurgical departments. One hundred patients with a preoperative diagnosis of intracranial meningioma or vestibular schwannoma subsequently confirmed on histological studies were included. All patients were older than 18 years of age, pregnancy had been excluded, there was no history of bleeding diathesis, no previous exposure to aprotinin, and no ingestion of antiplatelet or anticoagulant medications within the 2 weeks preceding surgery. Aprotinin was administered in doses of 30,000 kallikrein-inhibiting units (KIU)/kg body weight on induction of anesthesia and was continued as an infusion of 10,000 KIU/kg/hr until surgery was complete, or for a maximum of 8 hours. Intraoperative blood loss, blood transfusion, the Glasgow Outcome Scale score, and the Index of Independence were measured, and screening for deep vein thrombosis and the Mini-Mental State Examination were performed.

Conclusions. Intraoperative blood loss was reduced from 1014 ml (geometric mean) to 508 ml (p = 0.028). Although this study was not designed to evaluate the need for blood transfusion, 37 U of blood was used in 11 patients in the aprotinin group and 58 U in 13 patients in the placebo group (not significant). There were no significant differences in postoperative thrombotic risk or other outcome measures between treatment groups. Aprotinin therefore can be safely used to reduce intraoperative blood loss in patients who are not receiving anticoagulation therapy.
Hemorrhagic complication of stereotactic surgery in patients with movement disorders
Authors: Terao Tohru , Takahashi Hiroshi , Yokochi Fusako , Taniguchi Makoto , Okiyama Ryouichi , Hamada Ikuma
Published: May 2009

Object. Small, asymptomatic hemorrhages are easier to detect during stereotactic surgery when magnetic resonance (MR) imaging is used for targeting rather than when traditional approaches, such as ventriculography, are performed with contrast material. In the present study the authors examined the actual incidence of intraoperative hemorrhages in patients with movement disorders who had undergone MR imaging—targeted surgery, microelectrode recording (MER)-guided implantation of deep brain stimulation (DBS) electrodes, or radiofrequency-induced coagulation surgery performed.

Methods. Ninety-six consecutive patients underwent a total of 116 stereotactic operations for movement disorders (57 operations for radiofrequency-induced coagulation and 59 for DBS electrode implantation) between January 1998 and November 2002. The authors investigated the correlation between hemorrhages and other factors including the location of the hemorrhage and the type of surgery performed.

Postoperative computerized tomography scans demonstrated the occurrence of intraoperative hemorrhages at 12 locations during 11 procedures (9.5% of all procedures). Nine hemorrhages occurred during 57 coagulation operations (15.8%). Within this group, the frequency of hemorrhages was highest during thalamotomy (five [21.7%] of 23 procedures) and lower during pallidotomy (four [11.8%] of 34 procedures). In contrast, only two intraventricular hemorrhages developed during 59 operations in which DBS electrodes were implanted (3.4%). In no case was hemorrhage detected in the main DBS target, that is, the subthalamic nucleus.

Conclusions. When small, asymptomatic hemorrhages were included in the estimation, the actual rate of hemorrhage was higher than that previously reported. Judging from the incidence of hemorrhage during coagulation and DBS surgeries, the authors suggest that the heat induced by coagulation may play a larger role than microelectrode penetration in the development of hemorrhage.
Attenuation of nitric oxide synthase isoform expression by mild hypothermia after focal cerebral ischemia: variations depending on timing of cooling
Authors: Karabiyikoglu Murat , Han Hyung Soo , Yenari Midori A. , Steinberg Gary K.
Published: May 2009

Object. In this study the authors examined the influence of mild hypothermia on early expression of nitric oxide synthase (NOS) isoforms and peroxynitrite generation after experimental stroke.

Methods. In 82 male Sprague—Dawley rats, middle cerebral artery occlusion was performed for 2 hours by using the intraluminal suture model. The rats were maintained at their normal body temperature or exposed to 2 hours of intraischemic or postischemic (2-hour delay) mild hypothermia. Brains were collected 2, 6, and 24 hours after onset of ischemia for immunohistochemical and Western blot analysis of neuronal (n)NOS and inducible (i)NOS expression and peroxynitrite generation.

Conclusions. Western blots showed significantly increased nNOS and iNOS expression in the ischemic cortex at 2, 6, and 24 hours compared with sham-operated animals. The NOS expression was highest at 24 hours. Postischemic hypothermia attenuated nNOS expression at 6 and 24 hours to a greater extent than intraischemic hypothermia. Intraischemic hypothermia reduced iNOS expression at both 2 and 24 hours, whereas postischemic hypothermia decreased iNOS expression at 24 hours. Results of immunohistochemical studies showed that nNOS colocalized with the neuronal marker MAP-2 at all time points, whereas iNOS was initially localized to vessels, and then localized to activated microglia by 24 hours. Intraischemic but not postischemic hypothermia decreased the number of nitrotyrosine-positive cells in the ischemic cortex at 24 hours. Mild hypothermia significantly but differentially attenuates increases in NOS isoforms, with more robust nNOS suppression when cooling is delayed. This may have important implications for understanding the mechanism of hypothermic neuroprotection and for stroke therapy.
Validation of a near-infrared probe for detection of thin intracranial white matter structures
Authors: Giller Cole A. , Liu Hanli , Gurnani Prem , Victor Sundar , Yazdani Umar , German Dwight C.
Published: May 2009

Object. The authors have developed an intracranial near-infrared (NIR) probe that analyzes the scattering of light emitted from its tip to measure the optical properties of cerebral tissue. Despite its success in distinguishing gray matter from white matter in humans during stereotactic surgery, the limits of this instrument's resolution remain unclear. In this study, the authors determined the spatial resolution of this new probe by using a rodent model supplemented with phantom measurements and computer simulation.

Methods. A phantom consisting of Intralipid and gelatin was constructed to resemble a layer of white matter overlying a layer of gray matter. Near-infrared measurements were obtained as the probe was inserted through the gray—white matter transition. A computer simulation of NIR measurements through a gray—white matter transition was also performed using Monte Carlo techniques. The NIR probe was then used to study 19 tracks from the cortical surface through the corpus callosum in an in vivo rodent preparation. The animals were killed and histological sections through the tracks were obtained.

Data from the phantom models and computer simulations showed that the NIR probe samples a volume of tissue extending 1 to 1.5 mm in front of the probe tip (this distance is termed the “lookthrough” distance). Measurements obtained from an NIR probe passing through a thin layer of white matter consisted of an initial segment of increasing values, a maximum (peak) value, and a trailing segment of decreasing values. The length of the initial segment is the lookthrough distance, the position of the peak indicates the location of the superficial white matter boundary, and the length of the trailing segment is the thickness of the layer.

These considerations were confirmed in experiments with rodents. All tracks passed through the corpus callosum, which was demonstrated as a broad peak on each NIR graph. The position of the dorsal boundary of the corpus callosum and its width (based on histological measurements) correlated well with the peak of the NIR curve and its trailing segment, respectively. The initial segments correlated well with estimates of the lookthrough distance. Five of the tracks transected the smaller anterior commissure (diameter 0.2 mm), producing a narrow NIR peak at the correct depth.

Conclusions. Data in this study confirm that the NIR probe can reliably detect and measure the thickness of layers of white matter as thin as 0.2 mm. Such resolution should be adequate to detect larger structures of interest encountered during stereotactic surgery in humans.
Primary hypertension—induced cerebellar encephalopathy causing obstructive hydrocephalus
Authors: Verrees Meg , Filho Jose Americo Fernandes , Suarez Jose I. , Ratcheson Robert A.
Published: May 2009

✓ Hypertension-induced encephalopathy is a recognized pathological process commonly focused in the parietal and occipital lobes of the cerebral hemispheres. The parenchyma of the posterior fossa is infrequently involved. The authors report on two cases of isolated edema of the cerebellar hemispheres, which occurred in the setting of hypertensive crisis and led to complete obstruction of or significant impingement on the fourth ventricle and potentially lethal hydrocephalus. To the best of the authors' knowledge, these are the first reported cases of hypertensive encephalopathy centered in the posterior fossa.

Two patients presented with profound decreases in neurological status subsequent to development of malignant hypertension. Imaging studies revealed diffusely edematous cerebellar hemispheres with effacement of the fourth ventricle, causing dilation of the lateral and third ventricles. Following emergency placement of external ventricular drains, control of systemic blood pressure was accomplished, and neurological functioning returned to baseline.

Although neurological deterioration resolved swiftly following placement of ventricular catheters and administration of diuretic agents, systemic blood pressure did not fluctuate with the release of cerebrospinal fluid and resolution of increased intracranial pressure. Decrease in systemic blood pressure lagged well behind improvement in neurological status; the patients remained morbidly hypertensive until systemic blood pressure was controlled with multiple parenteral medications.

The authors hypothesize that the development of hypertension beyond the limits of cerebral autoregulation led to breakdown of the blood—brain barrier in the cerebellum and development of posterior fossa edema secondary to the focal transudation of protein and fluid. Correction of the elevated blood pressure led to amelioration of cerebellar edema. In the appropriate clinical setting, hypertension as the inciting cause of cerebellar encephalopathy should be considered.
Percutaneous intracranial stent placement for aneurysms
Authors: Han Patrick P. , Albuquerque Felipe C. , Ponce Francisco A. , Mackay Christopher I. , Zabramski Joseph M. , Spetzler Robert F. , McDougall Cameron G.
Published: May 2009

Object. Intracranial stent placement combined with coil embolization is an emerging procedure for the treatment of intracranial aneurysms. The authors report their results using intracranial stents for the treatment of intracranial aneurysms.

Methods. A prospectively maintained database was reviewed to identify all patients with intracranial aneurysms that were treated with intracranial stents. Ten lesions, including eight broad-based aneurysms and two dissecting aneurysms, were treated in 10 patients. Four lesions were located in the cavernous segment of the internal carotid artery, two at the vertebrobasilar junction, two at the basilar trunk, one at the basilar apex, and one in the intracranial vertebral artery. Attempts were made to place stents in 13 patients, but in three the stents could not be delivered. Altogether, intracranial stents were placed in 10 patients for 10 lesions.

Results that were determined to be satisfactory angiographically were achieved in all 10 lesions. Two patients suffered permanent neurological deterioration related to stent placement. In two patients, the aneurysm recurred after stent-assisted coil embolization. In one case of recurrence a second attempt at coil embolization was successful, whereas in the second case of recurrence parent vessel occlusion was required and well tolerated.

Conclusions. Intracranial stents can be a useful addition to coil embolization by providing mechanical, hemodynamic, and visual benefits in the treatment of complex, broad-based aneurysms.