bluuebunny/crossref_metadata_2025_split huggingface dataset:
The suboccipital cavernous sinus
Authors: Arnautovic Kenan I. , Al-Mefty Ossama , Pait T. Glenn , Krisht Ali F. , Husain Muhammad M. 
Published: January 2008

The authors studied the microsurgical anatomy of the suboccipital region, concentrating on the third segment (V3) of the vertebral artery (VA), which extends from the transverse foramen of the axis to the dural penetration of the VA, paying particular attention to its loops, branches, supporting fibrous rings, adjacent nerves, and surrounding venous structures.
Ten cadaver heads (20 sides) were fixed in formalin, their blood vessels were perfused with colored silicone rubber, and they were dissected under magnification. The authors subdivided the V3 into two parts, the horizontal (V3h) and the vertical (V3v), and studied the anatomical structures topographically, from the superficial to the deep tissues. In two additional specimens, serial histological sections were acquired through the V3 and its encircling elements to elucidate their cross-sectional anatomy. Measurements of surgically and clinically important features were obtained with the aid of an operating microscope.
This study reveals an astonishing anatomical resemblance between the suboccipital complex and the cavernous sinus, as follows: venous cushioning; anatomical properties of the V3 and those of the petrous-cavernous internal carotid artery (ICA), namely their loops, branches, supporting fibrous rings, and periarterial autonomic neural plexus; adjacent nerves; and skull base locations. Likewise, a review of the literature showed a related embryological development and functional and pathological features, as well as similar transitional patterns in the arterial walls of the V3 and the petrous-cavernous ICA. Hence, due to its similarity to the cavernous sinus, this suboccipital complex is here named the "suboccipital cavernous sinus." Its role in physiological and pathological conditions as they pertain to various clinical and surgical implications is also discussed.
Spinal cord stimulation with percutaneous and plate electrodes: side effects and quantitative comparisons
Authors: North Richard B. , Lanning Amy , Hessels Ryan , Cutchis Protagoras N. 
Published: January 2008

Spinal cord stimulation is limited by the uncomfortable side effects experienced by the patient as the amplitude of stimulation is increased. These side effects include local segmental paresthesias or motor responses, which are objectively demonstrable as frequency-following muscle contractions, attributable to dorsal root stimulation. The authors present evidence for another mechanism of stimulation-evoked discomfort, namely recruitment of small fibers in ligamentum flavum, which occurs when electrodes are inserted percutaneously and their contacts are exposed circumferentially; this does not occur with plate electrodes with insulated dorsal surfaces.
In a consecutive series of 79 patients with postsurgical lumbar pain syndromes, percutaneous four-contact electrodes were tested at levels from T-8 through T-12. At one or more levels, 46% of patients described paravertebral, nonradiating discomfort, unaccompanied by frequency-following muscle contractions. This was observed most commonly at the T-8 and T-9 levels. The effect was ameliorated in some cases by using multiple cathodes in parallel, which reduced the current density at individual contacts.
In 10 of these patients, this side effect interfered with an otherwise successful trial to such a degree that an insulated plate electrode was selected for permanent implantation at the same level as the percutaneous electrode. This eliminated the uncomfortable side effect completely in all patients. Intraoperative testing with the insulated plate electrode inverted (that is, contacts dorsal) reproduced the side effect in the majority of patients, indicating that structures dorsal to the electrode, such as fibers in ligamentum flavum, mediate the effect. Postoperative testing by computerized techniques demonstrated improved coverage of pain by stimulation paresthesias, with lower stimulation power requirements, using the insulated plate electrode.
This technical limitation of percutaneous spinal cord stimulation electrodes, which may confound treatment if unrecognized, has been found to have a straightforward solution which indicates the underlying mechanism.
Computerized tomography-guided percutaneous bilateral selective cordotomy
Authors: Kanpolat Yücel , Savas Ali , Çaglar Sükrü , Temiz Cüneyt , Akyar Serdar 
Published: January 2008

Percutaneous bilateral cordotomy performed using conventional techniques may cause the patient to develop sleep-induced apnea due to bilateral destruction of the ventrolateral reticulospinal tract. Computerized tomography (CT)-guided percutaneous cordotomy using a newly designed needle electrode system has the advantages of safe, selective, and controlled lesioning under direct visualization in the lateral spinothalamic tract. Given its low complication rate, bilateral selective cordotomy performed with CT guidance using this new needle electrode system may prove to be the treatment of choice for cancer patients with bilateral pain of the lower trunk and extremities.
The present series included five cancer patients suffering from intractable pain bilaterally in the lower trunk and extremities. All were treated with CT-guided bilateral selective cordotomy: the results demonstrate that this technique may be used effectively and safely.
Cerebral blood flow as a predictor of outcome following traumatic brain injury
Authors: Kelly Daniel F. , Martin Neil A. , Kordestani Rouzbeh , Counelis George , Hovda David A. , Bergsneider Marvin , Shalmon Ehud , McBride Duncan Q. , Herman Dena , Becker Donald P. 
Published: January 2008

As part of a prospective study of the cerebrovascular effects of head injury, 54 moderate and severely injured patients underwent 184 133Xe-cerebral blood flow (CBF) studies to determine the relationship between the period of maximum blood flow and outcome. The lowest blood flows were observed on the day of injury (Day 0) and the highest CBFs were documented on postinjury Days 1 to 5. Patients were divided into three groups based on CBF values obtained during this period of maximum flow: Group 1 (seven patients), CBF less than 33 ml/100 g/minute on all determinations; Group 2 (13 patients), CBF both less than and greater than or equal to 33 ml/100 g/minute; and Group 3 (34 patients), CBF greater than or equal to 33 ml/100 g/minute on all measurements. For Groups 1, 2, and 3, mean CBF during Days 1 to 5 postinjury was 25.7 ± 4, 36.5 ± 4.2, and 49.4 ± 9.3 ml/100 g/minute, respectively, and PaCO2 at the time of the CBF study was 31.4 ± 6, 32.7 ± 2.9, and 33.4 ± 4.7 mm Hg, respectively.
There were significant differences across Groups 1, 2, and 3 regarding mean age, percentage of individuals younger than 35 years of age (42.9%, 23.1%, and 76.5%, respectively), incidence of patients requiring evacuation of intradural hematomas (57.1%, 38.5%, and 17.6%, respectively) and incidence of abnormal pupils (57.1%, 61.5%, and 32.4%, respectively). Favorable neurological outcome at 6 months postinjury in Groups 1, 2, and 3 was 0%, 46.2%, and 58.8%, respectively (p < 0.05). Further analysis of patients in Group 3 revealed that of 14 with poor outcomes, six had one or more episodes of hyperemia-associated intracranial hypertension (simultaneous CBF > 55 ml/100 g/minute and ICP > 20 mm Hg). These six patients were unique in having the highest CBFs for postinjury Days 1 to 5 (mean 59.8 ml/100 g/minute) and the most severe degree of intracranial hypertension and reduced cerebral perfusion pressure (p < 0.0001).
These results indicate that a phasic elevation in CBF acutely after head injury is a necessary condition for achieving functional recovery. It is postulated that for the majority of patients, this rise in blood flow results from an increase in metabolic demands in the setting of intact vasoreactivity. In a minority of individuals, however, the constellation of supranormal CBF, severe intracranial hypertension, and poor outcome indicates a state of grossly impaired vasoreactivity with uncoupling between blood flow and metabolism.
Efficacy of bilateral pallidotomy
Authors: Kim Richard , Alterman Ron , Kelly Patrick J. , Fazzini Enrico , Eidelberg David , Beric Alaksandar , Sterio Djorje 
Published: January 2008

Unilateral pallidotomy is a safe and effective treatment for medically refractory bradykinetic Parkinson's disease, especially in those patients with levodopa-induced dyskinesia and severe on-off fluctuations. The efficacy of bilateral pallidotomy is less certain.
The authors completed 11 of 12 attempted bilateral pallidotomies among 150 patients undergoing pallidotomy at New York University. In all but one patient, the pallidotomies were separated by at least 9 months. Patients were selected for bilateral pallidotomy if they exhibited bilateral rigidity, bradykinesia, or levodopa-induced dyskinesia prior to treatment or if they exhibited disease progression contralateral to their previously treated side.
The Unified Parkinson's Disease Rating Scale (UPDRS) and timed upper-extremity tasks of the Core Assessment Protocol for Intracerebral Transplantation (CAPIT) were administered to all 12 patients in the “off” state (12 hours without receiving medications) preoperatively and again at 6 and 12 months after each procedure. The median UPDRS and contralateral CAPIT scores improved 60% following the initial procedure (p = 0.008, Wilcoxon rank sums test). The second pallidotomy generated only an additional 10% improvement in the UPDRS and CAPIT scores ipsilateral to the original procedure (p = 0.05). Worsened speech was observed in two cases. In the 12th case, total speech arrest was noted during test stimulation. Speech returned within minutes after stimulation was halted. Lesioning was not performed.
These results indicate that bilateral pallidotomy has a narrow therapeutic window. Motor improvement ipsilateral to the first lesion leaves little room for further improvement from the second lesion and the risk of speech deficit is greatly enhanced. Chronic pallidal stimulation contralateral to a previously successful pallidotomy may prove to be a safer alternative for the subset of patients who require bilateral procedures.
Gamma knife radiosurgery as a lesioning technique in movement disorder surgery
Authors: Young Ronald F. , Shumway-Cook Anne , Vermeulen Sandra S. , Grimm Peter , Blasko John , Posewitz Allen 
Published: January 2008

Fifty-five patients underwent radiosurgical placement of lesions either in the thalamus (27 patients) or globus pallidus (28 patients) for treatment of movement disorders. Patients were evaluated pre- and postoperatively by a team of observers skilled in the assessment of gait and movement disorders who were blinded to the procedure performed. They were not associated with the surgical team and concomitantly and blindly also assessed a group of 11 control patients with Parkinson's disease who did not undergo any surgical procedures. All stereotactic lesions were made with the Leksell gamma unit using the 4-mm secondary collimator helmet and a single isocenter with dose maximums from 120 to 160 Gy. Clinical follow-up evaluation indicated that 88% of patients who underwent thalamotomy became tremor free or nearly tremor free. Statistically significant improvements in performance were noted in the independent assessments of Unified Parkinson's Disease Rating Scale (UPDRS) scores in the patients undergoing thalamotomy. Eighty-five and seven-tenths percent of patients undergoing pallidotomy who had exhibited levodopa-induced dyskinesias had total or near-total relief of that symptom. Clinical assessment indicated improvement of bradykinesia and rigidity in 64.3% of patients who underwent pallidotomy. Independent blinded assessments did not reveal statistically significant improvements in Hoehn and Yahr scores or UPDRS scores. On the other hand, 64.7% of patients showed improvements in subscores of the UPDRS, including activities of daily living (58%), total contralateral score (58%), and contralateral motor scores (47%). Ipsilateral total UPDRS and ipsilateral motor scores were both improved in 59% of patients. One (1.8%) of 55 patients experienced a homonymous hemianopsia 9 months after pallidotomy due to an unexpectedly large lesion. No other complications of any kind were seen. Follow-up neuroimaging confirmed correct lesion location in all patients, with a mean maximum deviation from the planned target of 1 mm in the vertical axis. Measurements of lesions at regular interals on postoperative magnetic resonance images demonstrated considerable variability in lesion volumes. The safety and efficacy of functional lesions made with the gamma knife appear to be similar to those made with the assistance of electrophysiological guidance with open functional stereotactic procedures.
Functional lesions may be made safely and accurately using gamma knife radiosurgical techniques. The efficacy is equivalent to that reported for open techniques that use radiofrequency lesioning methods with electrophysiological guidance. Complications are very infrequent with the radiosurgical method. The use of functional radiosurgical lesioning to treat movement disorders is particularly attractive in older patients and those with major systemic diseases or coagulopathies; its use in the general movement disorder population seems reasonable as well.
Gamma knife radiosurgery for thalamotomy in Parkinsonian tremor: a five-year experience
Authors: Duma Christopher M. , Jacques Deane B. , Kopyov Oleg , Mark Rufus J. , Copcutt Brian , Farokhi Halle K. 
Published: January 2008

Certain patients, for example elderly, high-risk surgical patients, may be unfit for radiofrequency thalamotomy to treat Parkinsonian tremor. Some patients, when given the opportunity, may choose to avoid an invasive surgical procedure. The authors retrospectively reviewed their experience using gamma knife radiosurgery for thalamotomies in this patient subpopulation.
Radiosurgical nucleus ventralis intermedius thalamotomy using the gamma knife unit was performed to make 38 lesions in 24 men and 10 women (median age 73 years, range 58-87 years) over a 5-year period. A median radiation dose of 130 Gy (range 100-165 Gy) was delivered to 38 nuclei (four patients underwent bilateral thalamotomy) using a single 4-mm collimator following classic anatomical landmarks. Twenty-nine lesions were made in the left nucleus ventralis intermedius thalamus for right-sided tremor. Patients were followed for a median of 28 months (range 6-58 months). Independent neurological evaluation of tremor based on the change in the Unified Parkinson's Disease Rating Scale tremor score was correlated with subjective patient evaluation. Comparison was made between a subgroup of patients in whom “low-dose” lesions were made (range 110-135 Gy, mean 120 Gy) and those in whom “high-dose” lesions were made (range 140-165 Gy, mean 160 Gy) for purposes of dose-response information.
Four thalamotomies (10.5%) failed, four (10.5%) produced mild improvement, 11 (29%) produced good improvement, and 10 (26%) produced excellent relief of tremor. In nine thalamotomies (24%) the tremor was eliminated completely. The median time to onset of improvement was 2 months (range 1 week-8 months) Concordance between an independent neurologist's evaluation and that of the patient was statistically significant (p < 0.001). Two patients who underwent unilateral thalamotomy experienced bilateral improvement of their tremor. There were no neurological complications. There was better tremor reduction in the high-dose group when compared with the low-dose group (p < 0.04).
Although less effective than other stereotactic techniques, gamma knife radiosurgical thalamotomy offers tremor control with minimal risk to a patient population unsuited for open surgery.
Formation of autocrine loops in human cerebral meningioma tissue by leukemia inhibitor factor, interleukin-6, and oncostatin M: inhibition of meningioma cell growth in vitro by recombinant oncostatin M
Authors: Schrell Uwe M. H. , Koch Uwe , Marschalek Rolf , Schrauzer Thomas , Anders Marc , Adams Eric , Fahlbusch Rudolf 
Published: January 2008

It has been demonstrated that growth of cerebral meningiomas found in humans is controlled by a variety of factors, including growth factors, aminergic agents, neuropeptides, and steroids. The authors investigated the presence and function of the cytokines leukemia inhibitory factor (LIF), interleukin-6 (IL-6), and oncostatin M (OSM) on meningioma cell proliferation.
Active transcription of LIF, IL-6, OSM, their related receptors (LIF-R, IL-6-R, gp130), and the consecutive signal-transducing molecules (STAT 1, STAT 3, and STAT 5a) were analyzed in reverse transcriptase-polymerase chain reaction experiments.
The presence of endogenous LIF, IL-6, and OSM proteins was demonstrated in the supernatant of cultured meningioma cells using enzyme-linked immunosorbent assay and Western blot experiments, thus indicating an autocrine signaling pathway for all three cytokines.
The biological function of all three cytokines was evaluated by studying their effects on meningioma cell growth. Recombinant LIF and IL-6 showed no significant growth modulating effects; however, recombinant OSM decreased meningioma cell growth by 66%. The antiproliferative potency of OSM was demonstrated by cell count experiments, [3H]thymidine incorporation assay, and cell cycle analysis. These in vitro data support the concept that growth of meningioma cells may be modulated by cytokines and also indicates that recombinant OSM may be one of the future candidates for use in the adjuvant treatment of inoperable and recurrent meningiomas.
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: January 2008

Several lines of evidence indicate that the extent of ischemic injury is not defined immediately following arterial occlusion; rather that infarction expands over time. Episodes of spreading depression have been linked to this secondary increase in infarct volume. Tissue bordering the infarct fails to repolarize following spreading depression and is incorporated into the infarction. The result is that ischemic infarcts expand stepwise following each episode of spreading depression. Another line of evidence has demonstrated that gap junction blockers effectively inhibit spreading depression.
These observations suggest that the efflux of potentially harmful cytosolic messengers from ischemic cells into 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 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 following octanol treatment. Octanol pretreatment resulted in complete inhibition in two of nine animals, transient inhibition in five of nine, and no inhibition in two of nine.
The results indicate that gap junction inhibitors, when not limited by toxicity, have significant therapeutic potential in the treatment of acute stroke.
Hemicraniectomy with dural augmentation in medically uncontrollable hemispheric infarction
Authors: Wirtz Christian Rainer , Steiner Thorsten , Aschoff Alfred , Schwab Stefan , Schnippering Holger , Steiner Hans Herbert , Hacke Werner , Kunze Stefan 
Published: January 2008

Surgical decompression to alleviate raised intracranial pressure has been reported repeatedly in the past decades in small series of patients. Only recently have there been indications from larger trials that surgical decompression may be beneficial in treating space-occupying hemispheric infarction. However, surgical requirements for the procedure to be effective have not yet been defined.
Based on theoretical criteria, the authors operated on 43 patients with medically uncontrollable hemispheric infarctions. The craniectomies were planned to be as large as possible and performed in combination with a subtemporal decompression. Postoperative computerized tomography scans were evaluated for these criteria.
The mean survival rate for the group of 43 patients was 72.1% and no surviving patient ended up in a vegetative state. The mean area of craniectomy was found to be 84.3 ± 16.5 cm2 and the mean distance of the inferior craniectomy margin to the middle fossa was 1.8 ± 1.3 cm. Comparison of survivors and nonsurvivors failed to show a significant difference in the size of craniectomy or the distance to the floor of the middle fossa.
Compared with the reported 80% fatality rate for medically treated stroke patients, in this subgroup the outcome (72.1% survival rate) is remarkably good. The authors conclude that decompressive craniectomy is an effective treatment, able to reduce mortality, and to improve neurological outcome in patients with space-occupying cerebral infarction if the size of craniectomy is large enough. Nevertheless, there is a need for further investigation to identify patients who will benefit from surgery and predictors to optimize the timing of surgical intervention.
Contralateral approaches to bilateral cerebral aneurysms: a microsurgical anatomical study
Authors: Oshiro Eric M. , Rini David A. , Tamargo Rafael J. 
Published: January 2008

In patients with bilateral supratentorial aneurysms, surgical clipping of all aneurysms via a unilateral approach would obviate the need for a second operation. The authors conducted a microsurgical study in human cadaver heads to examine the contralateral exposure for four common aneurysm sites in the anterior circulation: the ophthalmic artery (OA) origin, the posterior communicating artery (PCoA) origin, the internal carotid artery (ICA) termination, and the middle cerebral artery (MCA) bifurcation. Frontotemporal craniotomies were performed in 16 cadavers to evaluate the corridor for exposure of these sites from the contralateral side. Morphometric data, including lengths and diameters of major arterial segments and optic nerves, were documented for anatomical correlation.
In this study, the contralateral OA origin was successfully exposed in 62% of specimens, the PCoA origin in 50%, the ICA bifurcation in 100%, and the MCA bifurcation in 62%. Exposure of the OA origin and, in some cases, the PCoA, required incision of the falciform ligament and mobilization of the contralateral optic nerve. Exposure of the MCA bifurcation was dependent on the length of the M1 segment, with successful exposure only when this segment was shorter than 14 mm. Implications for the contralateral approach to aneurysms at these sites are discussed and the microsurgical corridors for exposure are described.
For correlation with the anatomical study, a brief clinical review of patients with bilateral supratentorial aneurysms treated at The Johns Hopkins Hospital between 1992 and 1995 is presented. Guidelines for the contralateral approach to aneurysms are discussed with reference to the anatomical study and the clinical review.