bluuebunny/crossref_metadata_2025_split huggingface dataset:
Endoscope-assisted microsurgical resection of epidermoid tumors of the cerebellopontine angle
Authors: Schroeder Henry W. S. , Oertel Joachim , Gaab Michael R. 
Published: May 2009

Object. Epidermoid tumors located in the cerebellopontine angle (CPA) are challenging lesions because they grow along the subarachnoid spaces around delicate neurovascular structures and often extend into the middle cranial fossa. The purpose of this study was to determine the value of endoscopic assistance in the microsurgical resection of these lesions, in which total removal is the therapy of choice.
Methods. Eight patients harboring an epidermoid tumor of the CPA were treated using an endoscope-assisted microsurgical technique. A retrosigmoid suboccipital approach was used in five patients and a pterional transsylvian approach was chosen in the other three. In four patients the lesion was resected microsurgically and the endoscope was used repeatedly to verify complete tumor removal, whereas most of the tumor mass was removed with the aid of an operating microscope in the other four. Tumor parts extending into other cranial compartments that were not visible through the microscope were removed under endoscopic view by using rigid rod-lens scopes with 30 and 70° angles of view.
All epidermoids were completely evacuated and the membranes were widely resected. Large tumors occupying both the middle and posterior cranial fossa were removed through a single small opening without enlarging the craniotomy. Permanent hearing loss and permanent hypacusis were observed in one patient each. One patient with facial and one with abducent nerve palsy recovered within 6 and 4 months, respectively. A transient weakness of the chewing muscles was encountered in one patient. Postoperative magnetic resonance imaging revealed no residual tumor in any patient. To date no recurrences have been observed (follow up range 12–98 months).
Conclusions. The endoscope-assisted microsurgical technique enables safe removal even when tumor parts are not visible in a straight line. Tumor extensions into adjacent cranial compartments can be removed with the same approach without retracting neurovascular structures or enlarging the craniotomy.
Primary hypophysitis: a single-center experience in 16 cases
Authors: Leung Gilberto K. K. , Lopes Maria-Beatriz S. , Thorner Michael O. , Vance Mary Lee , Laws Edward R. 
Published: May 2009

Object.The authors review their experience in the treatment of 16 patients with primary hypophysitis.Methods.A retrospective study was undertaken to review cases of primary hypophysitis. The mean age of the patients was 47 years and there was an equal distribution of sexes. Recent pregnancy and underlying autoimmunity were noted in 50% of the patients. Two patients had undergone previous transsphenoidal operations at other centers, one for prolactinoma and another for hypophysitis. Headache, anterior pituitary deficiency, and suprasellar mass lesions were the most common presenting features. The initial presumptive diagnosis was pituitary adenoma in six patients (37.5%) and inflammatory hypophysitis in 10 (62.5%). Five patients received initial medical therapy for hypophysitis; although three (60%) responded satisfactorily, two (40%) did not and later underwent surgery.Altogether 13 patients (81.2%) underwent transsphenoidal surgery. The histological diagnoses were lymphocytic hypophysitis in 10 (76.9%) and granulomatous hypophysitis in three (23.1%) of the surgically treated patients. A coexistent Rathke cleft cyst was noted in one patient. There was no death in this series. One patient experienced postoperative cerebrospinal fluid leakage and meningitis. One patient had bilateral internal carotid artery occlusion secondary to inflammatory involvement of the cavernous sinuses and arteritis. This patient recovered and is capable of independent functional activities.Conclusions.All surgical patients experienced improvement in their headache and/or visual field defects and none had visual deterioration. None of the patients experienced any improvement in endocrine function and all required long-term hormone replacement. Transsphenoidal surgery was a safe and effective treatment especially for visual and pressure symptoms. A postoperative recurrence developed in two patients (15.4%) and the treatment modalities included steroid therapy, repeated surgery, and radiosurgery.
Quantification of in vivo Photofrin uptake by human pituitary adenoma tissue
Authors: Igbaseimokumo Usiakimi 
Published: May 2009

Object. Photofrin is widely distributed in the body after intravenous injection. This study was designed to quantify the preferential uptake of Photofrin by pituitary adenoma tissue for intraoperative photodynamic therapy.
Methods. Eight patients (seven men) with recurrent pituitary adenomas who had undergone previous surgery and radiation therapy were recruited for a Phase I/II feasibility study of the application of photodynamic therapy to pituitary tumors. Photofrin was administered intravenously at a dose of 2 mg/kg body weight 48 hours before repeated transsphenoidal hypophysectomy was performed. At the time of the operation, pituitary adenoma tissue, muscle, fat, skin, and plasma were obtained for measurement of Photofrin content by fluorometric assay.
The mean Photofrin level in pituitary adenoma tissue was 6.87 ng/mg (95% confidence interval [CI] 3.99–9.75), which was significantly higher than the uptake by skeletal muscle (2.24 ng/mg, 95% CI 1.28–3.2; p = 0.008), or fat (2.54 ng/mg, 95% CI 0.66–4.42; p = 0.007). Nevertheless, the mean drug concentration in pituitary adenoma tissue was not significantly different from the level in plasma (7.65 µg/ml, 95% CI 5.38–9.90; p = 0.558). Skin specimens were available in four patients, and these showed a mean uptake of 2.19 ng/mg.
Conclusions. Photofrin is preferentially retained by pituitary adenoma tissue to levels both adequate for intraoperative photodynamic therapy and approximately 50% higher than those reported for gliomas.
Seprafilm superior to Gore-Tex in the prevention of peridural fibrosis
Authors: Topsakal Cahide , Akpolat Nusret , Erol Fatih Serhat , Ozveren Mehmet Faik , Akdemir Ismail , Kaplan Metin , Tiftikci Murat , Kilic Nermin 
Published: May 2009

Object.This is an investigation into the effects of two barrier membranes in the prevention of peridural fibrosis in an animal model.Methods.Seprafilm or Gore-Tex was applied to a laminectomy defect overlying the dura mater in rats separated into treatment groups. A third group of rats underwent laminectomy only and served as controls. Two months postoperatively a histological study was performed to compare the amount of scar tissue in each group.The gross dissection demonstrated that both membranes created a controlled dissection plane, facilitated access to the epidural space, and provided a reduction in the amount of tissue adhering to the dura mater. Statistically, Seprafilm was superior to Gore-Tex in preventing peridural fibrosis (p < 0.05).Conclusions.Seprafilm can prevent peridural fibrosis better than Gore-Tex and can be used in humans in spinal surgery.
Blood—brain barrier opened by stimulation of the parasympathetic sphenopalatine ganglion: a new method for macromolecule delivery to the brain
Authors: Yarnitsky David , Gross Yossi , Lorian Adi , Shalev Alon , Lamensdorf Itschak , Bornstein Rinat , Shorer Shy , Mayevsky Avraham , Patel Kaushik P. , Abbott N. Joan , Mayhan William G. 
Published: May 2009

Object. Drug delivery across the blood—brain barrier remains a significant challenge. Based on earlier findings, the authors hypothesized that parasympathetic innervation of the brain vasculature could be used to augment drug delivery to the brain.
Methods. Using a craniotomy—cerebrospinal fluid superfusate paradigm in rats with an intravenous injection of tracer the authors demonstrated that stimulation of the postganglionic parasympathetic fibers of the sphenopalatine ganglion (SPG) increased the concentration of fluorescein isothiocyanate—dextran (4–250 kD) in the superfusate by two- to sixfold. A histological examination indicated the presence of dextran in the parenchyma. In another experiment the amount of Evans blue dye in the brain following SPG activation was similarly significantly elevated. The chemotherapeutic agents anti-HER2 monoclonal antibody and etoposide were also delivered to the brain and reached therapeutic concentrations. Brain homeostasis was not disturbed by this procedure; a measurement of nicotinamide adenine dinucleotide reduction did not show a decrease in the tissue metabolic state and brain water content did not increase significantly.
Conclusions. Sphenopalatine ganglion activation demonstrates a promising potential for clinical use in the delivery of small and large molecules to the brain.
Influence of oxygen therapy on glucose—lactate metabolism after diffuse brain injury
Authors: Reinert Michael , Schaller Benoit , Widmer Hans Rudolf , Seiler Rolf , Bullock Ross 
Published: May 2009

Object. Severe traumatic brain injury (TBI) imposes a huge metabolic load on brain tissue, which can be summarized initially as a state of hypermetabolism and hyperglycolysis. In experiments O2 consumption has been shown to increase early after trauma, especially in the presence of high lactate levels and forced O2 availability. In recent clinical studies the effect of increasing O2 availability on brain metabolism has been analyzed. By their nature, however, clinical trauma models suffer from a heterogeneous injury distribution. The aim of this study was to analyze, in a standardized diffuse brain injury model, the effect of increasing the fraction of inspired O2 on brain glucose and lactate levels, and to compare this effect with the metabolism of the noninjured sham-operated brain.
Methods. A diffuse severe TBI model developed by Foda and Maramarou, et al., in which a 420-g weight is dropped from a height of 2 m was used in this study. Forty-one male Wistar rats each weighing approximately 300 g were included. Anesthesized rats were monitored by placing a femoral arterial line for blood pressure and blood was drawn for a blood gas analysis. Two time periods were defined: Period A was defined as preinjury and Period B as postinjury. During Period B two levels of fraction of inspired oxygen (FiO2) were studied: air (FiO2 0.21) and oxygen (FiO2 1). Four groups were studied including sham-operated animals: air-air-sham (AAS); air-O2-sham (AOS); air-air-trauma (AAT); and air-O2-trauma (AOT). In six rats the effect of increasing the FiO2 on serum glucose and lactate was analyzed.
During Period B lactate values in the brain determined using microdialysis were significantly lower (p < 0.05) in the AOT group than in the AAT group and glucose values in the brain determined using microdialysis were significantly higher (p < 0.04). No differences were demonstrated in the other groups. Increasing the FiO2 had no significant effect on the serum levels of glucose and lactate.
Conclusions. Increasing the FiO2 influences dialysate glucose and lactate levels in injured brain tissue. Using an FiO2 of 1 influences brain metabolism in such a way that lactate is significantly reduced and glucose significantly increased. No changes in dialysate glucose and lactate values were found in the noninjured brain.
Functional role of the Na+/H+ exchanger in the regulation of cerebral arteriolar tone in rats
Authors: Saesue Prajak , Horiuchi Tetsuyoshi , Goto Tetsuya , Tanaka Yuichiro , Hongo Kazuhiro 
Published: May 2009

Object. In vascular smooth-muscle cells, the Na+/H+ exchanger (NHE) is involved in the regulation of [Na+]i, pHi through [H+], and cell volume. Recently, investigations have determined that this exchanger contributes to ischemia and reperfusion injury in coronary circulation. Nonetheless, there is limited information on this glycoprotein in cerebral circulation, especially microcirculation. Thus, the authors in the present study examined the role of NHE in the regulation of cerebral arteriolar tone and its related mechanisms in vitro.
Methods. The internal diameter of isolated pressurized intracerebral arterioles in rats was monitored with the aid of a microscope. To examine the basal activity of NHE two kinds of Na+/H+ exchange inhibitors (FR183998 and 5-[N,N-hexamethylene] amiloride) were administered in the arterioles. Furthermore the authors studied the effects of nitric oxide (NO) synthase inhibitor (NG methyl-l-arginine), Na+/K+—adenosine triphosphatase (NKA) inhibitor (ouabain), and the Na+/Ca++ exchange inhibitor (SEA0400) on the vascular response induced by either of the Na+/H+ exchange inhibitors.
Both of the Na+/H+ exchange inhibitors constricted the arteriole. Subsequent application of NO synthase inhibitor further decreased the diameter of the arterioles. The Na+/H+ exchange inhibitor—induced constriction was completely abolished in the presence of ouabain and SEA0400.
Conclusions. The NHE is active in the basal condition and regulates cerebral arteriolar tone through NKA and the Na+/Ca++ exchanger. Endogenous NO is not related to the activity of NHE in basal conditions.
Surgical repair of brachial plexus injury: a multinational survey of experienced peripheral nerve surgeons
Authors: Belzberg Allan J. , Dorsi Michael J. , Storm Phillip B. , Moriarity John L. 
Published: May 2009

Object.Brachial plexus injuries (BPIs) are often devastating events that lead to upper-extremity paralysis, rendering the limb a painful extraneous appendage. Fortunately, there are several nerve repair techniques that provide restoration of some function. Although there is general agreement in the medical community concerning which patients may benefit from surgical intervention, the actual repair technique for a given lesion is less clear. The authors sought to identify and better define areas of agreement and disagreement among experienced peripheral nerve surgeons as to the management of BPIs.Methods.The authors developed a detailed survey in two parts: one part addressing general issues related to BPI and the other presenting four clinical cases. The survey was mailed to 126 experienced peripheral nerve physicians and 49 (39%) participated in the study. The respondents represent 22 different countries and multiple surgical subspecialties. They performed a mean of 33 brachial plexus reconstructions annually. Areas of significant disagreement included the timing and indications for surgical intervention in birth-related palsy, treatment of neuroma-in-continuity, the best transfers to achieve elbow flexion and shoulder abduction, the use of intra- or extraplexal donors for motor neurotization, and the use of distal or proximal coaptation during nerve transfer.Conclusions.Experienced peripheral nerve surgeons disagree in important ways as to the management of BPI. The decisions made by the various treating physicians underscore the many areas of disagreement regarding the treatment of BPI, including the diagnostic approach to defining the injury, timing of and indications for surgical intervention in birth-related palsy, the treatment of neuroma-in-continuity, the choice of nerve transfers to achieve elbow flexion and shoulder abduction, the use of intra- or extraplexal donors for neurotization, and the use of distal or proximal coaptation during nerve transfer.
Quantitative analysis of radioisotope cisternography in the diagnosis of intracranial hypotension
Authors: Moriyama Eiji , Ogawa Tomoyuki , Nishida Ayumi , Ishikawa Shinichi , Beck Hiroichi 
Published: May 2009

Object. The authors attempted a quantitative analysis of conventional radioisotope cisternography for the purpose of more accurate diagnosis of intracranial hypotension.
Methods. Fifty-seven patients suspected of having intracranial hypotension underwent radioisotope cisternography. Whole-body images were obtained 2.5, 6, and 24 hours after intrathecal injection of 111In—diethylenetriamine pentaacetic acid. Radioactivity in the cerebrospinal fluid (CSF) space was counted during scanning, and radioisotope clearance was studied. Direct signs of radioisotope leakage into the spinal epidural space were found in 25 patients. Most leaks were located in the lumbosacral region. Analysis of the radioisotope clearance curve revealed two different patterns. In patients without a radiographically demonstrated radioisotope leak, absolutely exponential curves were observed (R2 > 0.99). The activity of the radioisotope decreased at a rate of e−0.03 to e−0.107 (mean ± standard deviation, e−0.056 ± 0.018; 32 patients). Clearance in patients with an overt radioisotope leak was not a simple exponential curve; it could be divided into an early rapid phase and a late slow phase. The clearance rate during the first 6 hours was e−0.219 ± 0.127 (25 patients) and e−0.076 ± 0.021 thereafter. The authors speculated that the early escape of undiluted radioisotope solution through an aberrant CSF outlet, such as a traumatic spinal dural tear, was responsible for this phenomenon.
Conclusions. The quantitative analysis featured in this study seems to be useful in the diagnosis of intracranial hypotension. A small CSF leak below the limit of radioisotope cisternography resolution might be detected using this technique.
Risk of persistent cranial nerve injury after carotid endarterectomy
Authors: Cunningham Edwin J. , Bond Rick , Mayberg Marc R. , Warlow Charles P. , Rothwell Peter M. 
Published: May 2009

Object. Cranial nerve injuries, particularly motor nerve injuries, following carotid endarterectomy (CEA) can be disabling and therefore patients should be given reliable information about the risks of sustaining such injuries. The reported frequency of cranial nerve injury in the published literature ranges from 3 to 23%, and there have been few series in which patients were routinely examined before and after surgery by a neurologist.
Methods. The authors investigated the risk of cranial nerve injuries in patients who underwent CEA in the European Carotid Surgery Trial (ECST), the largest series of patients undergoing CEA in which neurological assessment was performed before and after surgery. Cranial nerve injury was assessed and recorded in every patient and persisting deficits were identified on follow-up examination at 4 months and 1 year after randomization. Risk factors for cranial nerve injury were examined by performing univariate and multivariate analyses. There were 88 motor cranial nerve injuries among the 1739 patients undergoing CEA (5.1% of patients; 95% confidence interval [CI] 4.1–6.2). In 23 patients, the deficit had resolved by hospital discharge, leaving 3.7% of patients (95% CI 2.9–4.7) with a residual cranial nerve injury: 27 hypoglossal, 17 marginal mandibular, 17 recurrent laryngeal, one accessory nerve, and three Horner syndrome. In only nine patients (0.5%; 95% CI 0.24–0.98) the deficit was still present at the 4-month follow-up examination; however, none of the persisting deficits resolved during the subsequent follow up. Only duration of operation longer than 2 hours was independently associated with an increased risk of cranial nerve injury (hazard ratio 1.56, p < 0.0001).
Conclusions. The risk of motor cranial nerve injury persisting beyond hospital discharge after CEA is approximately 4%. The vast majority of neurological deficits resolve over the next few months, however, and permanent deficits are rare. Nevertheless, the risk of cranial nerve injury should be communicated to patients before they undergo surgery.
Variability of intraoperative electrocortical stimulation mapping parameters across and within individuals
Authors: Pouratian Nader , Cannestra Andrew F. , Bookheimer Susan Y. , Martin Neil A. , Toga Arthur W. 
Published: May 2009

Object. Electrocortical stimulation mapping is regarded as the gold standard of intraoperative mapping for predicting functional outcomes. Nevertheless, methodologies across institutions are inconsistent. Although many vary and maximize stimulation currents at each cortical site, some use a single current level to map the entire exposed cortex. The former comes at the cost of possibly inducing additional afterdischarge activity. The authors retrospectively reviewed their experience with intraoperative electrocortical stimulation mapping to characterize variability of both mapping and afterdischarge thresholds.
Methods. Seventeen patients satisfied the study inclusion criteria. Significant variability in mapping thresholds was identified within individuals and across the patient population. Moreover, a statistically significant difference in mapping thresholds was demonstrated between the frontal and parietal/temporal lobes (p = 0.007, one-way analysis of variance). The authors report a surprisingly high incidence of afterdischarge during mapping, wide variability in afterdischarge thresholds within individuals and across the study population, and mapping thresholds regularly exceeding afterdischarge thresholds in neighboring cortex. Differences in afterdischarge thresholds across lobes only approached significance (p = 0.086).
Conclusions. To maximize identification of eloquent cortices in some clinical situations, it may be advantageous to maximize currents at each cortical site regardless of adjacent afterdischarge threshold rather than to map the entire exposed cortex at a single current level. Moreover, the current findings highlight the need for electrocorticography during electrocortical stimulation mapping, both to identify when afterdischarges occur and to verify stimulation by recording stimulation artifacts. The advantages and limitations of maximizing currents at each cortical site as well as mapping at a single current level are discussed.
Neurotransmitter release from high-frequency stimulation of the subthalamic nucleus
Authors: Lee Kendall H. , Chang Su-Youne , Roberts David W. , Kim Uhnoh 
Published: May 2009

Object. High-frequency stimulation (HFS) delivered through implanted electrodes in the subthalamic nucleus (STN) has become an established treatment for Parkinson disease (PD). The precise mechanism of action of deep brain stimulation (DBS) in the STN is unknown, however. In the present study, the authors tested the hypothesis that HFS within the STN changes neuronal action potential firing rates during the stimulation period by modifying neurotransmitter release.
Methods. Intracellular electrophysiological recordings were obtained using sharp electrodes in rat STN neurons in an in vitro slice preparation. A concentric bipolar stimulating electrode was placed in the STN slice, and electrical stimulation (pulse width 50–100 µsec, duration 100–2000 µsec, amplitude 10–500 µA, and frequency 10–200 Hz) was delivered while simultaneously obtaining intracellular recordings from an STN neuron.
High-frequency stimulation of the STN either generated excitatory postsynaptic potentials (EPSPs) and increased the action potential frequency or it generated inhibitory postsynaptic potentials and decreased the action potential frequency of neurons within the STN. These effects were blocked after antagonists to glutamate and γ-aminobutyric acid were applied to the tissue slice, indicating that HFS resulted in the release of neurotransmitters. Intracellular recordings from substantia nigra pars compacta (SNc) dopaminergic neurons during HFS of the STN revealed increased generation of EPSPs and increased frequency of action potentials in SNc neurons.
Conclusions. During HFS of STN neurons the mechanism of DBS may involve the release of neurotransmitters rather than the primary electrogenic inhibition of neurons.