bluuebunny/crossref_metadata_2025 huggingface dataset:
Redefined role of angiogenesis in the pathogenesis of dural arteriovenous malformations
Authors: Lawton Michael T. , Jacobowitz Ronald , Spetzler Robert F.
Published: June 2009

✓ To investigate the role of angiogenesis in the pathogenesis of dural arteriovenous malformations (AVMs), 40 rats underwent common carotid artery—external jugular vein (CCA-EJV) anastomosis, bipolar coagulation of the vein draining the transverse sinus, and sagittal sinus thrombosis to induce venous hypertension. Fifteen rats underwent a similar surgical procedure, but venous hypertension was not induced. The 55 rats were divided into seven groups. Four groups, each containing 10 rats, underwent induced venous hypertension. The other three groups, each containing five rats, did not undergo induced venous hypertension. After 1, 2, or 3 weeks, dura mater was obtained from one group of hypertensive rats and from one group of nonhypertensive rats and was assayed for angiogenic activity (rabbit cornea bioassay). The remaining group of 10 hypertensive rats was not assayed to determine if sampling affected dural AVM formation. Unlike rats without CCA-EJV anastomosis, rats with CCA-EJV anastomosis had significantly increased postoperative sagittal sinus pressures (p < 0.0001). Mean angiogenesis indices were significantly greater in rats with venous hypertension than in rats without venous hypertension (p = 0.004). Dural AVMs formed in 42% of the 55 rats and facial AVMs formed in 51%. Angiogenic activity correlated positively with venous hypertension (ρ = 0.74). Development of dural AVMs correlated positively with both venous hypertension (p = 0.0009) and angiogenic activity (p = 0.04). These data indicate that venous hypertension may induce angiogenic activity either directly or indirectly by decreasing cerebral perfusion and increasing ischemia, and that dural AVM formation may be the result of aberrant angiogenesis.
Natriuretic peptide system and endothelin in aneurysmal subarachnoid hemorrhage
Authors: Wijdicks Eelco F. M. , Schievink Wouter I. , Burnett John C.
Published: June 2009

✓ The natriuretic peptide system consists of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP). The system is implicated in the control of body fluid homeostasis, causes natriuresis and diuresis (ANP and BNP), and regulates vascular tone (CNP). A reciprocal relationship between ANP and endothelin (ET) has been suggested, and earlier studies have documented a possible role of ET in cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH).

The authors studied plasma ANP, BNP, CNP, and ET for 6 consecutive days in 13 patients with SAH by using radioimmunoassay. The median admission values for ANP were 31.5 pg/ml (range 16.8–323 pg/ml [normal 15 ± 7 pg/ml]); for BNP, 45.3 pg/ml (range 2.2–80.2 pg/ml [normal 12 ± 9 pg/ml]); for CNP, 7.7 pg/ml (range < 2–20 pg/ml [normal 5.2 ± 3 pg/ml]); and for ET, 11 pg/ml (range 6.5–25.1 pg/ml [normal 7.2 ± 4 pg/ml]). Additional increases (defined as > 100% increase on two consecutive measurements) were noted in ANP (11 patients), BNP (10 patients), and CNP (three patients), and resulted in a negative fluid balance in 10 of the 13 patients. The CNP increased in three of four patients with cerebral vasospasm and in one of nine patients without cerebral vasospasm (Fisher's exact test, p = 0.2). No major fluctuations in plasma ET were noted. In seven patients, the plasma ET level did not increase beyond 10 pg/ml during the days of measurement. In six patients, only an occasional sample showed an increase to a maximum of 25 pg/ml. Changes in BNP, ANP, and CNP were independent of each other.

The authors conclude that both plasma ANP and BNP increase after SAH and often result in a negative fluid balance. Plasma ANP and BNP seem differentially regulated in the presence of SAH but not by the level of the plasma ET. The possible role of CNP as a regulatory response to cerebral vasospasm needs further exploration.
Prevention and reversal of cerebral vasospasm by an endothelin-converting enzyme inhibitor, CGS 26303, in an experimental model of subarachnoid hemorrhage
Authors: Kwan Aij-Lie , Bavbek Murad , Jeng Arco Y. , Maniara Wieslawa , Toyoda Tomikatsu , Lappe Rodney W. , Kassell Neal F. , Lee Kevin S.
Published: June 2009

✓ Delayed cerebral ischemia due to cerebral vasospasm is a major cause of morbidity and mortality in patients with aneurysmal subarachnoid hemorrhage (SAH). Increasing evidence implicates the potent vasoconstrictor peptide endothelin (ET) in the pathophysiology of cerebral vasospasm. In the present study the authors examined the therapeutic value of blocking the production of ET-1 by inhibiting the conversion of its relatively inactive precursor, Big ET-1, to a physiologically active form. An inhibitor of ET-converting enzyme (ECE), CGS 26303, was injected intravenously after inducing SAH in New Zealand white rabbits. Injections of CGS 26303 were initiated either 1 hour after SAH (prevention protocol) or 24 hours after SAH (reversal protocol). One of three concentrations (3, 10, or 30 mg/kg) of CGS 26303 was injected twice daily, and all animals were killed by perfusion fixation 48 hours after SAH occurred. Basilar arteries were removed and sectioned, and their cross-sectional areas were measured in a blind manner by using computer-assisted videomicroscopy.

Treatment with CGS 26303 attenuated arterial narrowing after SAH in both the prevention and reversal protocols. The protective effect of CGS 26303 achieved statistical significance at all dosages in the prevention protocol and at 30 mg/kg in the reversal protocol. These findings demonstrate that inhibiting the conversion of Big ET-1 to ET-1 via intravenous administration of an ECE inhibitor can be an effective strategy for limiting angiographic vasospasm after SAH. Moreover, the results demonstrate that treatment with the ECE inhibitor is capable of reducing vasospasm even when initiated after the process of arterial narrowing has begun. Finally, the results provide further support for the role of ET in the establishment of cerebral vasospasm. The ECE inhibitor CGS 26303 thus represents a promising therapeutic agent for the treatment of cerebral vasospasm following aneurysmal SAH.
Source and cause of endothelin-1 release into cerebrospinal fluid after subarachnoid hemorrhage
Authors: Pluta Ryszard M. , Boock Robert J. , Afshar John K. , Clouse Kathleen , Bacic Mima , Ehrenreich Hannelore , Oldfield Edward H.
Published: June 2009

✓ Despite years of research, delayed cerebral vasospasm remains a serious complication of subarachnoid hemorrhage (SAH). Recently, it has been proposed that endothelin-1 (ET-1) mediates vasospasm. The authors examined this hypothesis in a series of experiments. In a primate model of SAH, serial ET-1 levels were measured in samples from the perivascular space by using a microdialysis technique and in cerebrospinal fluid (CSF) and plasma during the development and resolution of delayed vasospasm. To determine whether elevated ET-1 production was a direct cause of vasospasm or acted secondary to ischemia, the authors also measured ET-1 levels in plasma and CSF after transient cerebral ischemia. To elucidate the source of ET-1, they measured its production in cultures of endothelial cells and astrocytes exposed to oxyhemoglobin (10 µM), methemoglobin (10 µM), or hypoxia (11% oxygen).

There was no correlation between the perivascular levels of ET-1 and the development of vasospasm or its resolution. Cerebrospinal fluid and plasma levels of ET-1 were not affected by vasospasm (CSF ET-1 levels were 9.3 ± 2.2 pg/ml and ET-1 plasma levels were 1.2 ± 0.6 pg/ml) before SAH and remained unchanged when vasospasm developed (7.1 ± 1.7 pg/ml in CSF and 2.7 ± 1.5 pg/ml in plasma). Transient cerebral ischemia evoked an increase of ET-1 levels in CSF (1 ± 0.4 pg/ml at the occlusion vs. 3.1 ± 0.6 pg/ml 4 hours after reperfusion; p < 0.05), which returned to normal (0.7 ± 0.3 pg/ml) after 24 hours. Endothelial cells and astrocytes in culture showed inhibition of ET-1 production 6 hours after exposure to hemoglobins. Hypoxia inhibited ET-1 release by endothelial cells at 24 hours (6.4 ± 0.8 pg/ml vs. 0.1 ± 0.1 pg/ml, control vs. hypoxic endothelial cells; p < 0.05) and at 48 hours (6.4 ± 0.6 pg/ml vs. 0 ± 0.1 pg/ml, control vs. hypoxic endothelial cells; p < 0.05), but in astrocytes hypoxia induced an increase of ET-1 at 6 hours (1.5 ± 0.6 vs. 6.4 ± 1.1 pg/ml, control vs. hypoxic astrocytes; p < 0.05).

Endothelin-1 is released from astrocytes, but not endothelial cells, during hypoxia and is released from the brain after transient ischemia. There is no relationship between ET-1 and vasospasm in vivo or between ET-1 and oxyhemoglobin, a putative agent of vasospasm, in vitro. The increase in ET-1 levels in CSF after SAH from a ruptured intracranial aneurysm appears to be the result of cerebral ischemia rather than reflecting the cause of cerebral vasospasm.
Expression and activation of epidermal growth factor receptors in meningiomas
Authors: Carroll Rona S. , Black Peter M. , Zhang Jianping , Kirsch Matthias , Percec Ivona , Lau Nelson , Guha Abhijit
Published: June 2009

✓ Previous studies have demonstrated expression of epidermal growth factor receptors (EGFRs) in human cerebral meningiomas. However, the activation status of the EGFRs and whether they activate cytoplasmic mitogenic signaling pathways are not known. In this study, using Northern blot analysis and the polymerase chain reaction, the authors report expression of epidermal growth factor, transforming growth factor—α, and EGFR messenger RNA in 27 meningioma specimens. Using Western blot and immunohistochemical analyses of the meningioma samples, the authors demonstrate that the EGFRs expressed by these meningiomas are activated. These activated EGFRs interact with and phosphorylate Shc, an SH2 domain—containing adapter protein that is important in transducing mitogenic signals from EGFRs to the nucleus via activation of the Ras signaling pathway. These results support the concept that activation of EGFRs in human meningiomas by autocrine/paracrine stimulation may contribute to their proliferation.
Tumor seeding following stereotactic biopsy of brain metastases
Authors: Karlsson Bengt , Ericson Kaj , Kihlström Lars , Grane Per
Published: June 2009

✓ In a series of 22 patients treated with gamma knife surgery for brain metastasis in whom biopsy specimens were obtained via stereotactically guided procedures before the radiosurgical treatment was administered, two cases with evidence of tumor seeding were observed on subsequent follow-up examination. These findings contradict the opinion that the risk for tumor spread after a biopsy is negligible. This evidence may be explained by the fact that radiosurgery leaves the surrounding tissue unaffected by the treatment, which results in preserved anatomy around the tumor. This allows the surgeon to define the previous biopsy channel and, consequently, whether a distant tumor recurrence may have resulted from tumor seeding related to the biopsy procedure. Additionally, radiosurgical treatment leaves tumor cells that may have been spread as a result of the biopsy unaffected, giving them the potential to divide and develop into a new tumor. In contrast to this, microsurgical removal of the tumor will affect the surrounding tissue, making it impossible to detect whether new metastases are resulting from seeding. Furthermore, conventional fractionated radiation therapy will sterilize tumor cells that may have spread, thus making it impossible for these cells to regrow.

The authors conclude that the risk for tumor seeding following a stereotactically guided biopsy may be higher than previously assumed.
Microelectrode-guided posteroventral pallidotomy for treatment of Parkinson's disease: postoperative magnetic resonance imaging analysis
Authors: Krauss Joachim K. , Desaloms J. Michael , Lai Eugene C. , King David E. , Jankovic Joseph , Grossman Robert G.
Published: June 2009

✓ The authors report the postoperative magnetic resonance (MR) imaging findings in 36 patients with advanced Parkinson's disease who underwent unilateral microelectrode-guided posteroventral pallidotomy. The lesions were placed within 1 mm of the ventral border of the globus pallidus internus (GPi) to include pallidothalamic outflow pathways. Sequential MR studies were obtained within 1 to 3 days postoperatively and at 6-month follow-up examination. Thirty-four (94%) of the 36 patients enjoyed sustained moderate or marked improvement of their parkinsonian symptoms 6 months postoperatively. Transient side effects occurred in five patients (14%), but there were no persistent complications. The pallidal radiofrequency lesions were prolate spheroid shaped and were composed of three concentric zones in the early postoperative studies. The mean volume of the middle zone, corresponding to the area of hemorrhagic coagulation necrosis, was 44.4 ± 17.6 mm3; the mean lesion volume as defined by the outer zone, corresponding to perilesional edema, was 262.2 ± 111.6 mm3. Additional edema spreading to the internal capsule was noted in 32 of 34 cases and to the optic tract in 11 of 34 cases. In two patients small ischemic infarctions involving the corona radiata were found, and in one a venous infarction was detected. Ischemic infarction resulted in mild transient Broca's aphasia in one patient, but there was no detectable neurological deficit in the other two. The mean volume of late-phase (6 months) lesions was 22 ± 28.8 mm3. In three patients no lesion was identified despite sustained clinical improvement. The lesion was located in the posteroventral GPi in all cases except in one patient in whom it was confined to the GP externus (GPe). This 49-year-old woman did not experience sustained benefit. The authors found no consistent correlations between lesion size and location and clinical outcome as measured by a global outcome score, the Unified Parkinson's Disease Rating Scale motor, activities of daily living, and bradykinesia “off” scores or rating of dyskinesias. Lesioning of pallidal and subpallidal pathways may contribute to the sustained clinical benefit in this series. Magnetic resonance imaging analysis showed that intraoperative microelectrode recording facilitated accurate placement of the lesion in this critical area.
The importance of pial blood supply to the development of peritumoral brain edema in meningiomas
Authors: Bitzer Michael , Wöckel Lars , Luft Andreas R. , Wakhloo Ajay K. , Petersen Dirk , Opitz Holger , Sievert Theo , Ernemann Ulrike , Voigt Karsten
Published: June 2009

✓ In a retrospective analysis, the authors studied the pial and dural blood supplies in 74 intracranial meningiomas and quantified their associated peritumoral brain edema (PTBE). The extent and localization of pial blush in relation to the total tumor volume were determined angiographically. The amount of edema and tumor size were calculated using computerized tomography. The edema—tumor volume ratio was defined as Edema Index (EI). There were 49 meningiomas with PTBE; of those tumors, 46 were supplied by pial vessels, and three were supplied exclusively by dural vessels. Tumors without PTBE showed no pial blush. The mean EI in meningiomas with pial blush was significantly larger (EI = 3) than in meningiomas without pial supply (EI = 1.1; p < 0.0001). Meningiomas with a smaller pial supply than dural supply had a significantly smaller mean EI than tumors with a pial supply equal to or greater than the dural supply (EI = 2.9 vs. EI = 3.7; p < 0.015). In 69.9% of cases with pial blood supply, major portions of the edema were located adjacent to the tumor region supplied by pial vessels. Edema index differences among tumors of different subgroups, as defined by size or histology, were significantly related to the pial supply in each subset. Thus, pial blood supply may be associated with the development of PTBE in meningiomas.
Evaluation with evoked and spontaneous electromyography during lumbar instrumentation: a prospective study
Authors: Welch William C. , Rose Robert D. , Balzer Jeffrey R. , Jacobs George B.
Published: June 2009

✓ The neuroanatomical structures that approximate the bony pedicles of the lumbar spine allow little room for technical error or compromise of the bone during pedicle screw insertion. Currently available neurophysiological monitoring techniques detect compromised bone and nerve root injury after it occurs. The purpose of this prospective study is to evaluate the reliability and efficacy of a unique neurophysiological monitoring technique. This technique provides immediate evaluation of pedicle cortical bone integrity in patients undergoing lumbar fusion with instrumentation by using electrified surgical instruments throughout the pedicle screw fusion procedure. Spontaneous electromyographic (EMG) activity was also monitored.

Intraoperative evoked EMG stimulation was performed using a pedicle probe and feeler as monopolar stimulators during the insertion of 164 pedicle bone screws in 32 patients. The EMG response to subthreshold stimulation intensities indicated cortical bone compromise. Immediate and conclusive feedback via evoked EMG activity using stimulating pedicle probes in appropriate muscle groups was successful in identifying pedicle cortical bone compromise in four patients. One false-negative evoked EMG study was noted but was identified via spontaneous EMG activity. Intraoperative EMG monitoring alerted the surgeon that redirection of the pedicle probe or screw was necessary to avoid nerve root irritation or injury and served as an early warning system.

Evoked EMG stimulation proved to be reliable and efficacious, especially when used in combination with spontaneous EMG. This technique may provide an added safeguard during implant placement procedures at centers where intraoperative neurophysiological monitoring is routinely performed.
Prospective assessment of continuous intrathecal infusion of baclofen for spasticity caused by acquired brain injury: a preliminary report
Authors: Meythaler Jay M. , McCary Anne , Hadley Mark N.
Published: June 2009

✓ Twelve consecutive patients with severe spasticity and hypertonia following acquired brain injury were treated with continuous intrathecal infusion of baclofen via an implanted, programmable infusion pump—catheter system for a minimum of 3 months. In every case intrathecal baclofen therapy resulted in a statistically significant reduction in upper- and lower-extremity tone, spasm frequency, and reflexes, contributing to improved functional abilities. There were no untoward side effects or complications associated with treatment.

This preliminary assessment indicates that intrathecal administration of baclofen is effective in treating the disabling spasticity caused by acquired brain injury in selected patients.
Role of glial filaments in cells and tumors of glial origin: a review
Authors: Rutka James T. , Murakami Masaji , Dirks Peter B. , Hubbard Sherri Lynn , Becker Laurence E. , Fukuyama Kozo , Jung Shin , Tsugu Atsushi , Matsuzawa Kazuhito
Published: June 2009

✓ In the adult human brain, normal astrocytes constitute nearly 40% of the total central nervous system (CNS) cell population and may assume a star-shaped configuration resembling epithelial cells insofar as the astrocytes remain intimately associated, through their cytoplasmic extensions, with the basement membrane of the capillary endothelial cells and the basal lamina of the glial limitans externa. Although their exact function remains unknown, in the past, astrocytes were thought to subserve an important supportive role for neurons, providing a favorable ionic environment, modulating extracellular levels of neurotransmitters, and serving as spacers that organize neurons. In immunohistochemical preparations, normal, reactive, and neoplastic astrocytes may be positively identified and distinguished from other CNS cell types by the expression of the astrocyte-specific intermediate filament glial fibrillary acidic protein (GFAP). Glial fibrillary acidic protein is a 50-kD intracytoplasmic filamentous protein that constitutes a portion of, and is specific for, the cytoskeleton of the astrocyte. This protein has proved to be the most specific marker for cells of astrocytic origin under normal and pathological conditions. Interestingly, with increasing astrocytic malignancy, there is progressive loss of GFAP production. As the human gene for GFAP has now been cloned and sequenced, this review begins with a summary of the molecular biology of GFAP including the proven utility of the GFAP promoter in targeting genes of interest to the CNS in transgenic animals. Based on the data provided the authors argue cogently for an expanded role of GFAP in complex cellular events such as cytoskeletal reorganization, maintenance of myelination, cell adhesion, and signaling pathways. As such, GFAP may not represent a mere mechanical integrator of cellular space, as has been previously thought. Rather, GFAP may provide docking sites for important kinases that recognize key cellular substrates that enable GFAP to form a dynamic continuum with microfilaments, integrin receptors, and the extracellular matrix.
Induction of hypercontractility in human cerebral arteries by rewarming following hypothermia: a possible role for tyrosine kinase
Authors: Sagher Oren , Huang Dah-Luen , Webb R. Clinton
Published: June 2009

✓ Induction of hypothermia is used routinely in neurosurgical and cardiovascular operations to protect the brain from ischemic insult. However, despite a plethora of experimental evidence supporting the use of hypothermia to protect the brain from ischemia, clinical experience using deliberate hypothermia in humans has not shown a convincing benefit. The authors tested the hypothesis that hypothermia and rewarming alter tone in human cerebral vessels and may interfere with cerebral perfusion in the setting of deliberate hypothermia. They examined human cerebral arteries during hypothermia (32°C and 17°C) and during rewarming to delineate the direct effects of cooling and rewarming on cerebrovascular tone. Artery segments obtained from autopsy material and from specimens excised at elective temporal lobectomies were tested in tissue baths using isometric tension measurements. Temperature-induced changes in vascular tone were measured and quantified with respect to contractile responses to serotonin (5-HT; 10−6 M). Cooling induced mild relaxation in cerebral vessels (−38 ± 12% 5-HT response in 50 vessels from autopsy specimens, −69 ± 10% 5-HT response in 51 vessels from lobectomy specimens). On rewarming, vessels contracted significantly beyond their baseline tone (108 ± 18% 5-HT response in 50 vessels from autopsy specimens, 42 ± 12% 5-HT response in 51 vessels from lobectomy specimens). Rewarming-induced hypercontractility was inhibited by the tyrosine kinase inhibitor genistein (−5 ± 7% vs. 70 ± 23% 5-HT response, genistein vs. control, 14 segments, p < 0.05) and enhanced by the tyrosine phosphatase inhibitor sodium orthovanadate (339 ± 54% vs. 104 ± 20% 5-HT response, sodium orthovanadate vs. control, five segments, p < 0.05), indicating a possible role for tyrosine kinase activation in the rewarming-induced contraction.
Stereotactic radiosurgical treatment of sphenopalatine neuralgia
Authors: Pollock Bruce E. , Kondziolka Douglas
Published: June 2009

✓ Sphenopalatine neuralgia is a rare craniofacial pain syndrome that is characterized by unilateral pain in the orbit, mouth, nose, and posterior mastoid process. During attacks of pain, vasomotor activity often results in ipsilateral nasal drainage, eye irritation, and lacrimation. The authors present a patient with a 15-year history of sphenopalatine neuralgia who underwent stereotactic radiosurgery targeted at the sphenopalatine ganglion, with initial pain relief, and repeated radiosurgery 17 months later for partial pain recurrence. Two years following radiosurgery, the patient is pain free, no longer suffering from nasal discharge and eye irritation.
Iatrogenic intradiploic meningoencephalocele
Authors: Martínez-Lage Juan F. , López Francisco , Piqueras Claudio , Poza Máximo
Published: June 2009

✓ The authors present the case of a 6-year-old girl who developed a right frontal intradiploic meningoencephalocele following an accidental dural tear produced during surgery for craniosynostosis. Although rare, growing skull fractures have been described in at least eight cases following the accidental laceration of the dura mater in the course of craniosynostosis repair. These cases closely resemble those produced by accidental trauma to the growing skull. However, the intradiploic location of a meningoencephalocele following surgery for craniosynostosis has not been documented previously. This patient presented with headache and a frontal tumor of bonelike consistency. Radiographs and computerized tomography scans of the skull revealed an intraosseous cyst, whereas magnetic resonance imaging demonstrated cerebral tissue herniation within the intradiploic tumor. Surgical treatment consisted of duraplasty and cranioplasty, which achieved good functional and cosmetic results. The pathogenesis of this unusual lesion is discussed and compared with the hypotheses advanced for explaining posttraumatic intradiploic cysts.
Bone flap fixation: a new technique
Authors: Spetzler Robert F.
Published: June 2009

✓ A new fixation technique for bone flaps is described. This technique avoids the use of hardware external to the skull in hairless areas where it may prove unsightly in patients with a thin scalp. The insertion of pins into the middle table of the skull firmly fixes bone flaps at one edge, eliminating the need for external plates at that site.
High-frequency stimulation of the globus pallidus internalis in Parkinson's disease: a study of seven cases
Authors: Gross Christian , Rougier Alain , Guehl Dominique , Boraud Thomas , Julien Jean , Bioulac Bernard
Published: June 2009

✓ The effectiveness of ventroposterolateral pallidotomy in the treatment of akinesia and rigidity is not a new discovery and agrees with recent investigations into the pathogenesis of Parkinson's disease, which highlight the role played by the unbridled activity of the subthalamic nucleus (STN) and the consequent overactivity of the globus pallidus internalis (GPi). Because high-frequency stimulation can reversibly incapacitate a nerve structure, we applied stimulation to the same target.

Seven patients suffering from severe Parkinson's disease (Stages III–V on the Hoehn and Yahr scale) and, particularly, bradykinesia, rigidity, and levodopa-induced dyskinesias underwent unilateral electrode implantation in the posteroventral GPi. Follow-up evaluation using the regular Unified Parkinson's Disease Rating Scale has been conducted for 1 year in all seven patients, 2 years in five of them, and 3 years in one. In all cases high-frequency stimulation has alleviated akinesia and rigidity and has generally improved gait and speech disturbances. In some cases tremor was attenuated. In a similar manner, the authors observed a marked diminution in levodopa-induced dyskinesias. This could be an excellent primary therapy for younger patients exhibiting severe bradykinesia, rigidity, and levodopa-induced dyskinesias, which would allow therapists to keep ventroposterolateral pallidotomy in reserve as a second weapon.
Patients with retained transcranial knife blades: a high-risk group
Authors: Taylor Allan G. , Peter Jonathan C.
Published: June 2009

✓ Sixty-six patients with transcranial stab wounds presenting to Groote Schuur Hospital over a 2-year period are reviewed. Two groups were identified, those with retained knife blades at presentation (Group A, 13 patients) and those without (Group B, 53 patients). An increased incidence of vascular complications was observed in Group A, (eight of 13 patients) compared with 11 of 53 patients in Group B (p < 0.01, chi-square test). The mortality rate was also higher in Group A, with deaths in three of 13 patients compared with four of 53 in Group B. Increased mortality was a result of vascular injury, and in two patients neurological deterioration occurred only after knife blade removal. Possible reasons for these findings are that retained blades tend to be deeply penetrating with a potential for more cerebral and vascular injury, and there is a higher incidence of petrous bone penetration that results in carotid artery injury.
Osteoblastoma of the nasal cavity invading the anterior skull base in a young child
Authors: Imai Keisuke , Tsujiguchi Kounosuke , Toda Chiaya , Sung Ki-Chul , Tajima Sadao , Sakamoto Hiroaki , Matsuda Yasuaki
Published: June 2009

✓ The benign osteoblastoma is rarely seen as a tumor of the facial bone in infancy or early childhood. Only five cases with nasal involvement have been reported in the literature. The authors present a case of osteoblastoma of the nasal cavity, the nasal bone, the ethmoid sinus, and the anterior cranial base.

This 3-year-old girl presented with a tumor surrounding the left medial canthus. Imaging studies, including x-ray films, computerized tomography scans, magnetic resonance images, a 99mTc-scintigram, and angiograms, confirmed the location of the tumor. A biopsy specimen of tumor was obtained intranasally and the pathological diagnosis was an osteoblastic tumor suggestive of osteoblastoma. Although the tumor margin was well defined on the radiological images, it was difficult to determine the exact margin during the operation. Therefore, it is important to show how to excise the tumor completely under direct view. With the use of a “dismasking flap,” it was possible to resect the benign osteoblastoma completely from the nasal cavity, even though it extended into the orbit, the maxilla, and the anterior cranial base.
Nonsurgical, nonorthotic treatment of occipital plagiocephaly: what is the natural history of the misshapen neonatal head?
Authors: Moss S. David
Published: June 2009

✓ Management of neonates with nonsynostotic occipital plagiocephaly has been controversial, and there has been a lack of uniformity concerning its treatment. Patients with nonsynostotic occipital plagiocephaly have been treated surgically or with cranial remodeling orthotic devices and have shown improvement in asymmetry. The cost of orthotic treatment has risen, and its validity has been contested by many third-party insurance payers. The effectiveness of orthotic treatment has not been adequately compared to the natural history of nonsynostotic occipital plagiocephaly. A nonsurgical, nonorthotic treatment study was initiated in June 1995 at Phoenix Children's Hospital. All new patients referred with a diagnosis of nonsynostotic occipital plagiocephaly were categorized into two groups: those with mild-to-moderate asymmetry and those with moderate-to-severe asymmetry. Categories were determined by cephalic measurements. The patients with moderate-to-severe asymmetry were offered orthotic treatment with a cranial remodeling band. Those patients with mild-to-moderate asymmetry were treated with physiotherapy, repositioning of the head, and repeated notation of cephalic measurements without orthotic devices or surgery. Seventy-two neonates, seen consecutively, with mild-to-moderate, nonsynostotic occipital plagiocephaly were evaluated by noting cephalic measurements. The parents of six of these patients elected treatment with a cranial remodeling band and results in these patients were excluded from our data. The remaining 66, treated without orthotic devices, showed improvement in average cranial vault asymmetry (CVA) from 9.2 to 4.7 mm over an average treatment period of 4.5 months that commenced when the average age of the patient was 6.4 months. A comparison of the present data with data published in 1994 for neonates treated with a headband indicates that neonates with mild-to-moderate asymmetry who are treated aggressively with physiotherapy and repositioning have similar improvement in CVA.
Complications associated with intraventricular chemotherapy in patients with leptomeningeal metastases
Authors: Chamberlain Marc C. , Kormanik Patty A. , Barba David
Published: June 2009

✓ The authors studied complications associated with intraventricular chemotherapy in patients with leptomeningeal metastases (LM). One hundred twenty consecutive patients with LM (71 females and 49 males) ranging in age from 10 to 72 years (median 42 years) were treated with involved-field radiotherapy and intraventricular chemotherapy using an Ommaya reservoir and intraventricular catheter system. The diagnosis of LM was determined by a combination of clinical presentation (114 patients); cerebrospinal fluid cytological studies (100); or neuroradiographic studies (42). Systemic tumor histological findings included breast (34 patients); non-Hodgkin's lymphoma (22); melanoma (16); primitive neuroectodermal tumors including medulloblastoma (10); glial neoplasms, leukemia, small cell lung, nonsmall cell lung, and colon (six each); prostate and kidney (three each); and gastric cancers (two). Sixteen patients, all with non-Hodgkin's lymphoma, also had acquired immune deficiency syndrome.

Patients received one to four (median two) chemotherapeutic drugs and underwent a total of 1110 cycles of intraventricular chemotherapy (median 10). Intraventricular chemotherapy administration and diagnostic Ommaya reservoir punctures totaled 4400, with a median of 46 per patient. Complications included aseptic/chemical meningitis (52 patients); myelosuppression due to intraventricular chemotherapy (21); catheter-related infections (nine); unidirectional catheter obstruction (six); intraventricular catheter malpositioning (two); Ommaya reservoir exposure (two); leukoencephalopathy (two); and chemotherapy-related myelopathy (one). There were no treatment-related deaths; however, seven patients (6%) required additional surgery for either catheter repositioning (two) or reservoir removal (five). Seven patients with catheter-related infections were treated successfully with intraventricular and systemic antibiotic drugs, thereby preserving the Ommaya system.

The authors conclude that Ommaya reservoirs are convenient and pharmacologically rational systems for administering intraventricular chemotherapy. Overall, serious complications requiring surgery are infrequent (6%) and most often secondary to catheter infections, Ommaya reservoir exposure, or initial catheter malpositioning. In the majority of instances, catheter infections may be managed medically, as may the most common complications of intraventricular chemotherapy including aseptic meningitis (43% of patients) and myelosuppression (18%).
Estrogens may reduce mortality and ischemic damage caused by middle cerebral artery occlusion in the female rat
Authors: Simpkins James W. , Rajakumar Gopal , Zhang Yu-Qi , Simpkins Christopher E. , Greenwald David , Yu Chun J. , Bodor Nicholas , Day Arthur L.
Published: June 2009

✓ The present study was undertaken to determine if estrogens protect female rats from the neurodegenerative effects of middle cerebral artery (MCA) occlusion. The rats were ovariectomized and 7 or 8 days later various estrogen preparations were administered before or after MCA occlusion. Pretreatment with 17β-estradiol (17β-E2) or a brain-targeted 17β-E2 chemical delivery system (CDS) decreased mortality from 65% in ovariectomized rats to 22% in 17β-E2—treated and 16% in 17β-E2 CDS—treated rats. This marked reduction in mortality was accompanied by a reduction in the ischemic area of the brain from 25.6 ± 5.7% in the ovariectomized rats to 9.8 ± 4% and 9.1 ± 4.2% in the 17β-E2—implanted and the 17β-E2 CDS—treated rats, respectively. Similarly, pretreatment with the presumed inactive estrogen, 17α-estradiol, reduced mortality from 36 to 0% and reduced the ischemic area by 55 to 81%. When administered 40 or 90 minutes after MCA occlusion, 17β-E2 CDS reduced the area of ischemia by 45 to 90% or 31%, respectively. In summary, the present study provides the first evidence that estrogens exert neuroprotective effects in an animal model of ischemia and suggests that estrogens may be a useful therapy to protect neurons against the neurodegenerative effects of stroke.
Completely dislocated hangman's fracture with a locked C2–3 facet
Authors: Choi Won Gyu , Vishteh A. Giancarlo , Baskin Jonathan J. , Marciano Frederick F. , Dickman Curtis A.
Published: June 2009

✓ The authors report a rare case of a hangman's fracture involving complete dislocation of C-2 onto C-3, accompanied by a C2–3 locked facet and asymptomatic bilateral vertebral artery injuries. The patient, a 25-year-old man who sustained a neck injury in an industrial accident, presented with a mild central spinal cord syndrome. His initial lateral cervical radiograph showed complete anterior dislocation of the C-2 body onto C-3, bilateral neural arch fractures, and a unilateral locked facet. The mechanism was likely flexion and compression. The grossly unstable spine and the locked facet were treated by posterior decompression, reduction, and C1–3 fixation. The patient recovered in several days and is without neurological deficit.
Total sacrectomy and Galveston L-rod reconstruction for malignant neoplasms
Authors: Gokaslan Ziya L. , Romsdahl Marvin M. , Kroll Stephen S. , Walsh Garrett L. , Gillis Theresa A. , Wildrick David M. , Leavens Milam E.
Published: June 2009

✓ Although radical resection is the best treatment for malignant sacral tumors, total sacrectomy for such tumors has been performed in only a few instances. Total sacral resection requires reconstruction of the pelvic ring plus establishment of a bilateral union between the lumbar spine and iliac bone. This technique is illustrated in two patients harboring large, painful, sacral giant-cell tumors that were unresponsive to prior treatment. These patients were treated with complete en bloc resection of the sacrum and complex iliolumbar reconstruction/stabilization and fusion. Surgery was performed in two stages, the first consisting of a midline celiotomy, dissection of visceral/neural structures, and ligation of internal iliac vessels, followed by an anterior L5—S1 discectomy. The second stage consisted of mobilization of an inferiorly based myocutaneous rectus abdominis pedicle flap for wound closure, followed by an L-5 laminectomy, bilateral L-5 foraminotomy, ligation of the thecal sac, division of sacral nerve roots, and transection of the ilia lateral to the tumor and sacroiliac joints. Placement of the instrumentation required segmental fixation of the lumbar spine from L-3 down by means of pedicle screws and the establishment of a bilateral liaison between the lumbar spine and the ilia by using the Galveston L-rod technique. The pelvic ring was then reestablished by means of a threaded rod connecting left and right ilia. Both autologous (posterior iliac crest) and allograft bone were used for fusion, and a tibial allograft strut was placed between the remaining ilia. The patients were immobilized for 8 weeks postoperatively and underwent progressive rehabilitation. At the 1-year follow-up review, one patient could walk unassisted, and the other ambulated independently using a cane. Both patients controlled bowel function satisfactorily with laxatives and diet and could maintain continence but required self-catheterization for bladder emptying. The authors conclude that in selected patients, total sacrectomy represents an acceptable surgical procedure that can offer not only effective local pain control, but also a potential cure, while preserving satisfactory ambulatory capacity and neurological function.
Intraoperative monitoring of substrate delivery during aneurysm and hematoma surgery: initial experience in 16 patients
Authors: Doppenberg Egon M. R. , Watson Joe C. , Broaddus William C. , Holloway Kathryn L. , Young Harold F. , Bullock Ross
Published: June 2009

✓ The effects of proximal occlusion of the parent artery during aneurysm surgery in humans are not fully understood, although this method is widely used. The reduction in substrate that can be tolerated by normal and subarachnoid hemorrhage (SAH)—affected brain is unknown. Therefore, the authors measured brain oxygen tension (brain PO2), carbon dioxide tension (brain PCO2), pH, and hemoglobin oxygen (HbO2) saturation before and after temporary occlusion in 12 patients with aneurysms. The effect of removal of a traumatic intracranial hematoma on cerebral oxygenation was also studied in four severely head injured patients.

A multiparameter sensor was placed in the cortex of interest and locked by means of a specially designed skull bolt. The mean arterial blood pressure, inspired O2 fraction, and end-tidal PCO2 were analyzed. Brain PO2 and HbO2 saturation data were collected every 10 seconds. Descriptive and nonparametric analyses were used to analyze the data.

A wide range in baseline PO2 was seen, although a decrease from baseline in brain PO2 was found in all patients. During temporary occlusion, brain PO2 in patients with unruptured aneurysm (seven patients) dropped significantly, from 60 ± 31 to 27 ± 17 mm Hg (p < 0.05). In the SAH group (five patients), the brain PO2 dropped from 106 ± 74 to 87 ± 73 mm Hg (not significant). Removal of intracranial hematomas in four severely head injured patients resulted in a significant increase in brain PO2, from 13 ± 9 to 34 ± 13 mm Hg (p < 0.05).

The duration of safe temporary occlusion could not be determined from this group of patients, because none developed postoperative deterioration in their neurological status. However, the data indicate that this technique is useful to detect changes in substrate delivery during intraoperative maneuvers. This study also reemphasizes the need for emergency removal of intracranial hematomas to improve substrate delivery in severely head injured patients.
Management-related morbidity in unselected aneurysms of the upper basilar artery
Authors: Redekop Gary J. , Durity Felix A. , Woodhurst W. Barrie
Published: June 2009

✓ A series of 49 consecutively treated patients with 52 aneurysms of the upper basilar artery (BA) is presented. Thirtynine aneurysms arose at the BA bifurcation, 11 at the origin of the superior cerebellar artery (SCA), and two from the upper BA trunk just below the SCA. The patient population consisted of 36 women and 13 men, with a mean age of 50 years (range 23–74 years). Of the 35 patients presenting with subarachnoid hemorrhage, 10 were Grade I, 10 were Grade II, 11 were Grade III, and four were Grade IV according to the Hunt and Hess scale. Treatment consisted of aneurysm neck clipping in 28, proximal occlusion of the BA in three, and endovascular therapy with coils in four patients. The remaining 14 patients with unruptured aneurysms underwent direct neck clipping. Postoperatively, 38 patients developed diplopia in at least one direction of gaze but this had resolved in 31 of them at the last follow-up evaluation. There were four deaths (8.2%): two as a result of rebleeding following coil compaction at 8 days and 9 months posttreatment, respectively; one as a result of vasospasm; and one as a result of brainstem infarction after proximal occlusion of the BA in a giant bifurcation aneurysm. Of the surviving patients, 33 (67.3%) made an excellent recovery, seven (14.3%) made a good recovery, and five (10.2%) were in poor condition at the last follow-up review. Direct microsurgical clipping of most aneurysms of the BA apex region can be performed with acceptable rates of morbidity. These data from an unselected series of patients in a general hospital provide a basis for comparison with developing alternative techniques.
Effective reduction of infarct volume by gap junction blockade in a rodent model of stroke
Authors: Rawanduzy Ahmed , Hansen Anker , Hansen Thomas W. , Nedergaard Maiken
Published: June 2009

✓ Several lines of evidence indicate that the extent of ischemic injury is not defined immediately after arterial occlusion, but that infarction expands over time. Episodes of spreading depression have been linked to this secondary increase in infarct volume. Tissue bordering the infarction fails to repolarize following spreading depression and is incorporated into the lesion. The result is that ischemic infarctions expand stepwise after each episode of spreading depression. Another line of evidence has demonstrated that gap junction blockers effectively inhibit spreading depression.

These observations suggest that traffic of potentially harmful cytosolic messengers between ischemic cells and surrounding nonischemic cells might cause amplification of injury in focal stroke. It is therefore conceivable that minimizing gap junction permeability might reduce final infarct volume. To test this hypothesis, the authors pretreated rats with the gap junction blocker, octanol, before occluding the middle cerebral artery and compared the sizes of the ischemic lesions to those in rats that received the vehicle, dimethyl sulfoxide, prior to arterial occlusion. Histopathological analysis was performed 24 hours later. The 12 octanol-treated animals showed a significantly decreased mean infarction volume (80 ± 16 mm3) compared with the nine control rats (148 ± 9 mm3). In a separate set of experiments, the frequency of experimentally induced waves of spreading depression was evaluated after octanol treatment. Octanol pretreatment resulted in complete inhibition in two of nine animals, transient inhibition in five, and no inhibition in two.

The results indicate that gap junction inhibitors, when not limited by toxicity, have significant therapeutic potential in the treatment of acute stroke.
Carotid endarterectomy performed after progressive carotid stenosis following angioplasty and stent placement
Authors: Vale Fernando L. , Fisher Winfield S. , Jordan William D. , Palmer Cheryl A. , Vitek Jiri
Published: June 2009

✓ Carotid endarterectomy (CEA) is the treatment of choice for asymptomatic and symptomatic disease causing greater than 60% internal carotid artery (ICA) stenosis. Recently, percutaneous transluminal angioplasty (PTA) with stent placement has been investigated as a therapeutic option for the treatment of ICA stenosis. In this report the authors document CEA performed after PTA with stent placement and describe the pathological findings.

A standard CEA was performed. The surgical intervention was more difficult secondary to the following variables: the length of the exposure necessary to dissect out the metallic stent, the difficulty with opening and cutting the artery, and the care required to remove the stent to avoid vessel wall perforation. Pathological examination of the specimen demonstrated classic atherosclerotic changes revealing persistence of native disease. The metallic stent was embedded within the plaque. Many questions remain unanswered regarding the physiological and biological changes that occur in the carotid vessel wall after PTA with stent placement. It is concluded that CEA of a stent-containing carotid artery is feasible and should be considered as an alternative when recurrent stenosis occurs after PTA.
Tentorial edge traumatic aneurysm of the superior cerebellar artery
Authors: Proust François , Callonec Françoise , Bellow Francis , Laquerriere Annie , Hannequin Didier , Fréger Pierre
Published: June 2009

✓ The authors report an unusual case of a traumatic aneurysm of the right superior cerebellar artery (SCA). A 22-year-old woman presented with continuous headaches that appeared 15 days after she experienced closed head trauma as a result of a cycling accident. Computerized tomography scanning performed 3 months later showed a nodular lesion on the free edge of the tentorium, which mimicked a meningioma. The aneurysm was identified on magnetic resonance angiography, which showed the SCA as the parent vessel. The parent vessel was trapped, and the aneurysm sac was excised via right temporal craniotomy. Pathological examination of the sac revealed a false aneurysm. The patient's outcome was excellent. The pathophysiology of traumatic aneurysm at such a location suggests that surgery may be the treatment of choice.