bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluid Diversion Monitoring: The Key to Treatment Optimization
Authors: Glasbergen Gerard , Yeager Valerie , Reyes Robert , Everett Don
Published: May 2009

In stimulation and injection treatments for removing or preventing formation damage, placement of the injected fluids is essential. Throughout the years, several diversion and placement techniques have been applied to obtain a desired fluid placement. A recent development is the application of distributed temperature sensing (DTS) to monitor the temperature profiles along the wellbore in real time during these treatments. Recent case histories showed that fluid placement can be quantified. Quantification of fluid distribution enables one to determine the flow distribution both before and after a diverter stage so that the diversion effect can be quantified.

This paper discusses several case histories where DTS was applied to quantify the effectiveness of different diverters. The effects of chemical diverters, such as relative permeability modifiers (RPM) and in-situ crosslinked acids (ICAs), and more traditional diverters, such as rock salt, are discussed. Because of the advanced monitoring used with the temperature profiles, both the immediate and the sustained effect of the diverters can be measured. The changes in the flow distribution are not limited to diverters. Reactive fluid or changes in flow rate can change the flow distribution as well. These effects were measured during the stimulation treatments.

The post-treatment analysis of the measured temperature profiles in combination with treatment pressures and flow rate information resulted in accurate knowledge of the effectiveness of the different diverters and stimulation effects over time. This knowledge will be used in future treatments to help optimize volumes, rates, fluid systems, and the selection of the appropriate diverter.
Understanding the Near-wellbore Phenomena for Hydraulically Fractured wells: A Comprehensive Inflow Performance Numerical Model
Authors: Jimenez Maria-Alejandra , Chavez Juan Carlos
Published: May 2009

Comprehensive hydraulic fracture simulation models have been used to predict fracture propagation behaviour, geometry and conductivity. Extensive studies have been made in order to calibrate and assess the accuracy of these predictions; this has made possible the development of highly accurate models such as the 3D fracture simulation programs currently in use. However, when estimating the production performance of the hydraulically fractured wells, an essential step during hydraulic fracture designs, in most cases analytical approaches are used, which have the limitation that they that cannot reproduce the complexities associated with flow from the near wellbore area into the well.

The introduction of formation damage (skin) factors to account for the complexities associated with the flow in the near wellbore area further limits understanding as to how the sand-face completion and final fracture design interact, limiting the ability to provide an optimum implementation that maximises the well performance.

A comprehensive numerical model, which considers Computational Fluid Dynamics (CFD), was used to estimate the inflow performance of single and multiple fractured wells, taking into consideration reservoir heterogeneities and completion characteristics. Porous media inertial and viscous effects were accounted for, considering different sets of values for the formation and the fracture(s) domains. 3D CFD was used to identify the impact of the perforation strategy, multilayer reservoir fracture intersection, multiple fractures and petrophysical heterogeneities on well performance for oil reservoirs. The study demonstrates, through the detailed understanding of the inflow in the near wellbore area, that it is possible to optimize the sand-face completion design and has been applied on a field re-development project on a multilayer reservoir system.

The use of CFD supported by today's available computational capabilities, provides the base platform to increase the understanding of the near wellbore flow behaviour in fractured wells leading to optimum sand-face completion and final production performance.
New Fundamental Insights into Perforation-Induced Formation Damage
Authors: Heiland Juliane , Grove Brenden , Harvey Jeremy , Walton Ian , Martin Andrew
Published: May 2009

Shaped charge perforating subjects the formation to shock-loading and large impact stresses, causing damage to the rock surrounding the perforation tunnel. This damage can lead to reduced productivity and to an enhanced risk of sand production, both of which are undesirable. The impact stresses fracture sand grains in the vicinity of the perforation tunnel, resulting in a zone of reduced permeability called the crushed zone. Additionally, the impact stresses plus the outward traveling shock wave severely weaken the rock matrix by de-bonding the cohesive inter-granular cementation, leading to the creation of a zone of reduced strength called the damage zone. As a result, the damage zone extends to a greater depth than the crushed zone. This weakened damage zone is an important factor in crushed zone removal and in the onset of sand production.

An essential first step in modeling perforation clean-up is to characterize the extent and magnitude of both the permeability and strength impairment. An indirect measure of the amount of permeability impairment created by the perforating process is obtained from perforation flow experiments, where the post-shot production flow is compared to an idealized flow measurement in the virgin rock. Direct measurement of the extent of the crushed and damaged zones, and the degree to which strength and permeability damage occurred has received very little attention. In this paper new methods are described to directly determine the extent of the strength and permeability damage caused by shaped-charge penetration. The crushed zone permeability impairment is characterized using thin section analysis and the strength damaged zone is characterized using a Scratch-Tester. These methods allow the quantitative assessment of both damage zones,. The implications of the results for productivity impairment and sand production will be discussed.
Methylprednisolone or naloxone treatment after acute spinal cord injury: 1-year follow-up data
Authors: Bracken Michael B. , Shepard Mary Jo , Collins William F. , Holford Theodore R. , Baskin David S. , Eisenberg Howard M. , Flamm Eugene , Leo-Summers Linda , Maroon Joseph C. , Marshall Lawrence F. , Perot Phanor L. , Piepmeier Joseph , Sonntag Volker K. H. , Wagner Franklin C. , Wilberger James L. , Winn H. Richard , Young Wise
Published: May 2009

✓ The 1-year follow-up data of a multicenter randomized controlled trial of methylprednisolone (30 mg/kg bolus and 5.4 mg/kg/hr for 23 hours) or naloxone (5.4 mg/kg bolus and 4.0 mg/kg/hr for 23 hours) treatment for acute spinal cord injury are reported and compared with placebo results. In patients treated with methylprednisolone within 8 hours of injury, increased recovery of neurological function was seen at 6 weeks and at 6 months and continued to be observed 1 year after injury. For motor function, this difference was statistically significant (p = 0.030), and was found in patients with total sensory and motor loss in the emergency room (p = 0.019) and in those with some preservation of motor and sensory function (p = 0.024). Naloxone-treated patients did not show significantly greater recovery. Patients treated after 8 hours of injury recovered less motor function if receiving methylprednisolone (p = 0.08) or naloxone (p = 0.10) as compared with those given placebo. Complication and mortality rates were similar in either group of treated patients as compared with the placebo group. The authors conclude that treatment with the study dose of methylprednisolone is indicated for acute spinal cord trauma, but only if it can be started within 8 hours of injury.
Aggressive surgical management of craniopharyngiomas in children
Authors: Hoffman Harold J. , Silva Marcia De , Humphreys Robin P. , Drake James M. , Smith Mary Lou , Blaser Susan I.
Published: May 2009

✓ The cases of 50 patients with craniopharyngioma operated on at The Hospital for Sick Children in Toronto between January, 1975, and December, 1989, are reviewed. All patients were under 18 years of age (mean 9.39 years). Headaches, endocrine deficiences, and visual deficits were the most common symptoms on admission. Forty-five patients underwent what was considered by the surgeon to be total excision of their tumor, and five had subtotal excision. Tumors recurred in 17 patients (mean time of recurrence 32.6 months after surgery). One patient died in the postoperative period and three have been lost to follow-up study. Of the remaining 46 patients, 28 are leading a normal or nearly normal life, although all are receiving endocrine replacement and some have required help to overcome mild deficits in memory or visual acuity. Twelve patients are able to function reasonably well and attend school despite being hampered by intellectual or visual deficits or problems with weight control; four have a significant handicap, and two have died.
Leksell's posteroventral pallidotomy in the treatment of Parkinson's disease
Authors: Laitinen Lauri V. , Bergenheim A. Tommy , Hariz Marwan I.
Published: May 2009

✓ Between 1985 and 1990, the authors performed stereotactic posteroventral pallidotomies on 38 patients with Parkinson's disease whose main complaint was hypokinesia. Upon re-examination 2 to 71 months after surgery (mean 28 months), complete or almost complete relief of rigidity and hypokinesia was observed in 92% of the patients. Of the 32 patients who before surgery also suffered from tremor, 26 (81%) had complete or almost complete relief of tremor. The L-dopa-induced dyskinesias and muscle pain had greatly improved or disappeared in most patients, and gait and speech volume also showed remarkable improvement. Complications were observed in seven patients: six had a permanent partial homonymous hemianopsia (one also had transient dysphasia and facial weakness) and one developed transitory hemiparesis 1 week after pallidotomy.

The results presented here confirm the 1960 findings of Svennilson, et al., that parkinsonian tremor, rigidity, and hypokinesia can be effectively abolished by posteroventral pallidotomy, an approach developed in 1956 and 1957 by Lars Leksell. The positive effect of posteroventral pallidotomy is believed to be based on the interruption of some striopallidal or subthalamopallidal pathways, which results in disinhibition of medial pallidal activity necessary for movement control.
Chemical monitoring of neurosurgical intensive care patients using intracerebral microdialysis
Authors: Persson Lennart , Hillered Lars
Published: May 2009

✓ The authors have used intracerebral microdialysis to develop a method for routine monitoring of disturbances in brain energy metabolism in patients in the neurosurgical intensive care unit. Microdialysis was conducted for periods ranging from 2.3 to 8.3 days in four patients (three with severe head injuries and one with severe subarachnoid hemorrhage). Altogether, 4447 chemical analyses from 587 dialysis samples were carried out. Concentrations of the energy-related metabolites lactate, pyruvate, and hypoxanthine were measured, and the lactate:pyruvate ratio was calculated. In addition, the amino acids glutamate, aspartate, taurine, glutamine, asparagine, and glycine were measured in one patient. The microdialysis data were matched with various clinical events, including intracranial hypertension and therapeutic interventions such as initiation or withdrawal of barbiturates and cerebrospinal fluid drainage. The present study shows that microdialysis can be used for long-term measurement of extracellular fluid (ECF) energy-related metabolites and amino acids in the frontal cortex of neurosurgical patients in a clinical setting. Fluctuations of the measured ECF energy-related substances corresponded to various clinical events presumably involving hypoxia/ischemia. The authors found a 25-fold increase in ECF glutamate, aspartate, and taurine under conditions of energy perturbation, as indicated by high levels of the lactate:pyruvate ratio, lactate, and hypoxanthine. The use of long-term intracerebral microdialysis in patients opens a new field of clinical research, with many possibilities for improving insight into intracranial dynamics in acute cerebral conditions.
Efficacy of LY233053, a competitive glutamate antagonist, in experimental central nervous system ischemia
Authors: Madden Kenneth P. , Clark Wayne M. , Kochhar Abha , Zivin Justin A.
Published: May 2009

✓ Antagonists of excitatory amino acids appear to serve a neuroprotective role during ischemic conditions in a variety of in vivo and in vitro models. The usefulness of such agents in the clinical setting, however, may be limited by poor central nervous system (CNS) entry and intolerable side effects. The authors report high efficacy in reducing neurological damage and relatively limited side effects of LY233053, a novel competitive glutamate antagonist, in two models of experimental CNS ischemia in the rabbit.
Iatrogenic arteriovenous fistula presenting as a recurrent subdural hematoma
Authors: Pappas Conrad T. E. , Zabramski Joseph M. , Shetter Andrew G.
Published: May 2009

✓ An unusual case of an iatrogenic dural arteriovenous fistula is reported. The patient presented with a history of progressive generalized headache over a period of 3 to 4 weeks. Computerized tomography demonstrated a chronic subdural hematoma that was successfully evacuated by burr-hole drainage. The patient's postoperative course was complicated by recurrent acute subdural hematomas at the drainage site. Coagulation studies were unremarkable. Selective external carotid angiography demonstrated a small dural arteriovenous fistula adjacent to the burr hole used for the initial operative procedure. Extension of the bone flap and coagulation of the fistula resulted in a good outcome. In the patient with recurrent acute subdural hematoma, the possibility of a vascular malformation must be considered. Selective internal and external carotid angiography is key to the correct diagnosis.
Fibroma of the meninges in a child: immunohistological and ultrastructural study
Authors: Reyes-Mugica Miguel , Chou Pauline , Gonzalez-Crussi Frank , Tomita Tadanori
Published: May 2009

✓ A case of meningeal fibroma in a 5-year-old girl is described. The lesion presented as a benign intracranial tumor, eroding the frontal bone and protruding under the skin. It was composed of fibroblasts and collagen, embedded in a loose background with focal myxoid changes. The authors describe the patient's clinical presentation and the tumor's histological, immunohistochemical, and ultrastructural features, and discuss its differential diagnosis. It is concluded that fibromas of the meninges should be distinguished from fibroblastic meningiomas.
Relief of akinetic mutism from obstructive hydrocephalus using bromocriptine and ephedrine
Authors: Anderson Britt
Published: May 2009

✓ The case of a 20-year-old man with obstructive hydrocephalus who suffered multiple shunt failures and shunt revisions is presented. The patient gradually developed a clinical syndrome of akinetic mutism. This behavioral syndrome failed to respond to shunt revisions, but did improve after the administration of a combination of bromocriptine and ephedrine.
Current results of the retrosigmoid approach to acoustic neurinoma
Authors: Ebersold Michael J. , Harner Stephen G. , Beatty Charles W. , Harper C. Michel , Quast Lynn M.
Published: May 2009

✓ Since 1984 when cranial nerve monitoring became routinely performed at the Mayo Clinic, 255 patients have undergone 256 procedures using the retrosigmoid approach for the removal of acoustic neurinomas. Of these, 221 patients had some hearing before surgery and 52 maintained hearing following surgery. The anatomical continuity of the facial nerve was preserved in 237 of these 256 procedures. It was possible to perform a primary end-to-end anastomosis in seven of the remaining 19 patients, and one patient had a cable graft inserted. Thus, 95.7% of these patients were believed to have potential for spontaneous facial nerve function. Of the 11 patients in whom this was not possible, seven underwent early spinal accessory facial anastomosis, in two hypoglossal-facial anastomosis was performed, and two had no facial nerve procedures and have paralysis of the facial nerve.

There were two deaths from a pulmonary embolus in the early postoperative period, both 4 days following otherwise uneventful surgery. The most common postoperative complication was cerebrospinal fluid leakage, which has not resulted in significant permanent morbidity although early repair for this problem is now routinely recommended. Other complications were quite rare and have generally not resulted in any major change in patient lifestyle or activity level. This review reconfirms that the retrosigmoid surgical treatment of acoustic tumors continues to be an acceptable treatment option.
Hearing preservation in acoustic neurinoma surgery
Authors: Fischer Georges , Fischer Catherine , Rémond Joël
Published: May 2009

✓ The authors have reviewed hearing results obtained in 99 patients operated on via the suboccipital approach for acoustic neurinoma, who were not deaf prior to surgery (pure tone average < 70 dB). Tumor size was less than 10 mm in four cases, 10 to 19 mm in 26 cases, 20 to 29 mm in 39 cases, and 30 mm or greater in 30 cases. Removal was macroscopically complete in 92 cases and incomplete in seven, including four cases with bilateral acoustic neurofibromatosis. Hearing was preserved in 29 patients (29.3%), of whom 23 had neurinomas smaller than 30 mm and six had tumors exceeding 30 mm in size. Postoperative hearing was good in eight cases (four with neurinomas < 20 mm and four with neurinomas > 20 mm), serviceable in four cases (three with neurinomas < 20 mm and one with a tumor > 30 mm), and poor in 17 cases (eight with neurinomas < 20 mm and nine with tumors > 20 mm). Fifty-seven patients underwent intraoperative brain-stem auditory evoked potential monitoring: the rate of hearing preservation was found to be higher in this group than in the 42 without monitoring (p < 0.05). A statistical study using stepwise regression analysis showed that the two preoperative factors most significantly associated with postoperative hearing preservation are a good auditory level for low frequencies measured by pure tone audiometry and a small-sized tumor. Overall results indicate that, even if hearing is more easily preserved when the neurinoma is small and the preoperative auditory condition is good, the surgeon should try to save hearing in all patients who have preserved hearing before surgery.
Reconstruction of the third through sixth cranial nerves during cavernous sinus surgery
Authors: Sekhar Laligam N. , Lanzino Giuseppe , Sen Chandra N. , Pomonis Spiros
Published: May 2009

✓ Sixteen reconstruction procedures of the third through sixth cranial nerves were carried out in 14 patients during operations on 149 tumors involving the cavernous sinus. A direct end-to-end anastomosis was performed in five nerves, whereas in 11 cases the nerve stumps were bridged by means of an interposing nerve graft. The sixth cranial nerve was most frequently reconstructed (nine cases). In four cases, the fifth nerve or root was repaired. The third nerve was reconstructed in two patients, and the fourth nerve was repaired in only one case.

Recovery of function, either partial or complete, was observed in 13 nerves: the third in two instances, the fourth in one, the fifth in three, and the sixth in seven. No return of function occurred in three nerves. In patients with a successful recovery of cranial nerve function, either binocular function or the cosmetic result was improved. These results suggest that repair of the third through sixth cranial nerves injured during surgery should be pursued in suitable patients.
Patient-interactive, computer-controlled neurological stimulation system: clinical efficacy in spinal cord stimulator adjustment
Authors: North Richard B. , Fowler Kim , Nigrin Daniel J. , Szymanski Richard
Published: May 2009

✓ Over the past 20 years, continuing technical advances have rendered spinal cord stimulation an easily implemented low-morbidity technique for the management of chronic intractable pain in properly selected patients. Percutaneous methods for the insertion of arrays of multiple epidural electrodes, which are driven by noninvasively programmable “multichannel” implanted devices, have been among the most important of these technical improvements. The same implanted electronics may be used with peripheral nerve or intracerebral electrodes.

If the capabilities of this new hardware are to be used to full advantage, a major investment of time and effort is required to adjust the system postoperatively for optimum effect. Ideally, these adjustments should be based upon psychophysical data, obtained in a manner that minimizes influences such as potential operator bias or stimulus presentation-order effects.

These requirements have been met by the development of a computerized system designed for direct patient interaction and for greater ease of operation than the standard external devices used with these implants. The system has been tested clinically in 25 patients with spinal cord stimulation for pain. It rapidly tests the available electrode combinations and stimulus pulse parameters at a rate comparable to or greater than that of a skilled human operator using the standard device. It records detailed graphic data and patient analog ratings at varying thresholds and implements “pain drawing” methods with novel input and analytical techniques.

This patient-interactive computerized system has proved to be safe and effective clinically. The time required by the average patient working with this system to adjust the stimulator is comparable to or less than the time required by the same patient working with a physician's assistant. Psychophysical data collected by the system may be correlated with clinical observations. Ongoing development will permit delivery of novel pulse sequences and protocols to assess the mechanisms by which stimulation affords relief from pain.
Chronic stimulation of the Kölliker-Fuse nucleus region for relief of intractable pain in humans
Authors: Young Ronald F. , Tronnier Volker , Rinaldi Patricia C.
Published: May 2009

✓ Chronic electrical stimulation in the periventricular or periaqueductal gray matter regions and the thalamic somatosensory relay nuclei (ventralis posteromedialis and ventralis posterolateralis) provides long-term pain relief in about 50% of patients with intractable pain refractory to other conservative and/or surgical measures. To enhance the success of electrical stimulation in relief of pain, alternative brain and brain-stem targets have been sought. A series of laboratory studies indicated that the Kölliker-Fuse nucleus and the parabrachial region may provide appropriate alternatives to the “classic” targets. This report describes six patients with intractable chronic pain of nociceptive or central origin, in whom an electrode was stereotactically implanted in the region of the Kölliker-Fuse nucleus. Kölliker-Fuse nucleus stimulation alone or in combination with stimulation in the periaqueductal/periventricular gray matter region or the somatosensory thalamic nuclei provided excellent pain relief in three of the six patients.
Multiple vertebral hemangiomas with neurological signs
Authors: Djindjian Michel , Nguyen Jean-Paul , Gaston André , Pavlovitch Jean-Marc , Poirier Jacques , Awad Issam A.
Published: May 2009

✓ A case of multiple vertebral hemangiomas with progressive neurological deficit is presented. Successful treatment was accomplished using preoperative embolization, palliative surgical decompression, and postoperative radiation therapy. The patient has remained asymptomatic for 6 years. The authors review the role of current imaging modalities and options for therapeutic intervention. Preoperative embolization, palliative surgical decompression, and postoperative radiotherapy appear to provide a satisfactory outcome in patients with multiple hemangiomas and may represent an effective alternative to more aggressive surgical intervention.
The Krause operations
Authors: Rosegay Harold
Published: May 2009

✓ Some of Fedor Krause's contributions to operative technique are reviewed and portrayed as fundamental steps in the progress of neurological surgery. The approaches he devised, the “Krause operations,” are exposure of the trigeminal ganglion and root, of the cerebellopontine angle, and of the pituitary (transfrontal) and the pineal (supracerebellar) regions. This review recalls the significance of the aggregate body of Krause's work, which has not been fully appreciated except by his compatriots.
Clinical outcome of radiosurgery for cerebral arteriovenous malformations
Authors: Steiner Ladislau , Lindquist Christer , Adler John R. , Torner James C. , Alves Wayne , Steiner Melita
Published: May 2009

✓ The clinical outcomes are described for 247 consecutive cases of arteriovenous malformation (AVM) treated with the gamma knife between April, 1970, and December 31, 1983. Headache resolved in 65 (66.3%) of the 98 patients presenting with this symptom and improved in an additional nine (9.2%). Of 59 patients admitted with seizures, 11 (18.6%) became seizure-free without anticonvulsant medication and an additional 30 patients (50.8%) became seizure-free with anticonvulsant medication. Pre-existing neurological deficits improved or totally disappeared following radiosurgery in 56.7% of affected cases. This improvement presumably occurred within the frame of the natural history.

The protective effect of the ionizing beams against hemorrhage in incompletely obliterated AVM's is analyzed. To assess the rate of rebleeding, probability estimates were calculated using both the person-year method and the Kaplan-Meier life table. With the person-year method the actual rebleed rate is not too different from the values observed in the natural history of the disease (2% to 3%/yr). Analysis by Kaplan-Meier life-table estimates demonstrated a risk of nearly 3.7%/yr until 60 months after radiosurgery. Five years following treatment, the life table ends in a plateau which could be interpreted as an indication of decrease in the risk of hemorrhage. However, long flat regions at the right end of the life table do not imply that the real risk of rebleeding is negligible unless a large number of patients have been followed well into or beyond the flat region.
The effect of changes in cerebral perfusion pressure upon middle cerebral artery blood flow velocity and jugular bulb venous oxygen saturation after severe brain injury
Authors: Chan Kwan-Hon , Miller J. Douglas , Dearden N. Mark , Andrews Peter J. D. , Midgley Susan
Published: May 2009

✓ Middle cerebral artery blood flow velocity and jugular bulb venous oxygen saturation (SJO2) were measured by transcranial Doppler (TCD) ultrasonography and continuous venous oximetry, respectively, in 41 severely brain-injured patients. The purpose of the study was to examine the relationships between TCD flow velocity, SJO2, and alterations in blood pressure (BP), intracranial pressure (ICP), and cerebral perfusion pressure (CPP).

In these patients, CPP was reduced either by rising ICP or by falling BP. Both forms of reduction of CPP resulted in a greater fall in diastolic flow velocity than other flow parameters. As CPP decreased below a critical value of 70 mm Hg, a progressive increase in TCD pulsatility index (PI) was observed (r = −0.942, p < 0.0001), accompanied by a fall in SJO2 (r = 0.78, p < 0.0001). At pressures above 70 mm Hg, there was no correlation of either PI or SJO2 with CPP. The relationship between PI and CPP held true in patients with both focal and diffuse pathologies and was the same whether changes in CPP resulted from alterations in ICP or BP. The PI and SJO2 correlated better with CPP than with ICP or BP.

Transcranial Doppler ultrasonography can identify states of reduced CPP. Decreases in SJO2 with falling CPP suggested progressive failure of cerebral blood flow to meet metabolic demands. Monitoring of TCD and SJO2 may be used to define the optimum CPP level for management of severely brain-injured patients.
Scoliosis in pediatric Chiari malformations without myelodysplasia
Authors: Muhonen Michael G. , Menezes Arnold H. , Sawin Paul D. , Weinstein Stuart L.
Published: May 2009

✓ A prospective study was undertaken in 1985 to better understand how the surgical manipulation of hind-brain herniation affected abnormal spinal curvature. Eleven patients under 16 years of age with Chiari malformation (not associated with myelodysplasia) and scoliosis of at least 15° were studied. The mean curve angle at the time of original treatment was 29°, with the convexity to the right in seven patients. The curvature was rapidly progressing in four patients. The most common presenting signs were myelopathy and weakness. Investigative procedures included spine radiographs with the patient standing and magnetic resonance (MR) imaging of the brain, spinal cord, and craniovertebral junction. Eight children had associated hydrosyringomyelia.

Surgical intervention consisted of a dorsal posterior fossa decompression in all patients and a transoral ventral decompression of the cervicomedullary junction in five. All patients were followed at 3, 6, and 12 months, and at yearly intervals thereafter with clinical evaluations, spine radiographs in the standing position, and postoperative MR imaging. The mean follow-up period was 35 months. The scoliosis improved in eight patients, stabilized in one, and progressed in two. Only one child required postoperative spinal fusion and instrumentation for progression of scoliosis. Hematomyelia or hematobulbia was associated with persistent scoliosis in two patients. The presence of hydrosyringomyelia and bone erosion did not preclude curve improvement. All patients under 10 years of age had resolution of their scoliosis, despite preoperative curves of more than 40°. These findings emphasize the importance of early surgical intervention, with the restoration of normal cerebrospinal fluid dynamics at the craniovertebral junction in children with symptomatic Chiari malformations.
Clinical effect of intra-arterial tumor necrosis factor-α for malignant glioma
Authors: Yoshida Jun , Wakabayashi Toshihiko , Mizuno Masaaki , Sugita Kenichiro , Yoshida Tazuka , Hori Shigeaki , Mori Teruaki , Sato Tomohiko , Karashima Atsushi , Kurisu Kaoru , Kiya Katsuzo , Uozumi Tohru
Published: May 2009

✓ Recombinant human tumor necrosis factor-α was administered intra-arterially to treat 20 cases of malignant gliomas, mostly progressive or recurrent. The optimum dosage was determined to be 1 × 105 U/sq m/day. Among the 10 evaluable patients treated at this dosage, two responded (one completely and one partially), resulting in a 20% response rate. Side effects were mild and easily controllable. Improvement of neurological symptoms was noted in 47% of the patients a few days after treatment, even when computerized tomography showed no tumor regression. This might have been due to the pleiotypic biological activity of tumor necrosis factor-α. Neuroradiographic observations revealed narrowing of the tumor-feeding artery, a decrease in tumor staining ability, and necrosis in the central part of a tumor. The authors suggest that intra-arterial administration of tumor necrosis factor-α may be an effective treatment for malignant glioma, including recurrent cases.
Epidural steroids, postoperative morbidity, and recovery in patients undergoing microsurgical lumbar discectomy
Authors: Lavyne Michael H. , Bilsky Mark H.
Published: May 2009

✓ Intraoperative epidural corticosteroids have been used by some surgeons to decrease pain following surgery for a herniated lumbar disc. In this study, 84 consecutively treated, comparable patients with unilateral lumbar disc herniation were prospectively assigned randomly to receive either epidural corticosteroids (40 mg methylprednisolone acetate) or saline at the conclusion of the operative procedure. The postoperative morbidity of these two groups was evaluated by tabulating the following parameters: pain relief as measured by consumption of postoperative pain medications; the length of hospital stay; postoperative functional status; and the time interval from surgery until return to work. The mean postoperative analgesic medications consumed was 12.2 ± 1.9 mg of morphine equivalents in the corticosteroid group versus 12.2 ± 1.8 mg of morphine equivalents in the control group. The mean hospital stay was less than 2 days in each group, and the mean interval until return to work was 21.2 ± 2.7 days in the corticosteroid group versus 25.4 ± 3.1 days in the control group. Moreover, no statistically significant difference was measured between the steroid-treated and control groups when the data were stratified for sex, age, and site of disc herniation. The mean outcome scores, which are derived from a postoperative assessment of pain relief resulting from surgery, functional status, and interval until return to work, were identical in the corticosteroid and control groups. This study concludes that epidural corticosteroid administration after microsurgical lumbar discectomy for unilateral disc herniation does not lessen postoperative morbidity or improve functional recovery.
Measurement of tumor resection volumes from computerized images
Authors: Duong Duc H. , Rostomily Robert C. , Haynor David R. , Keles G. Evren , Berger Mitchel S.
Published: May 2009

✓ The authors describe a method for quantitation of the area and volume of the resection cavity in patients who have undergone surgery for brain tumors. Using a slide scanner and Image 1.27, a public domain program for the Apple Macintosh II computer, computerized tomography scans and magnetic resonance images can be digitized and analyzed for a particular region of interest, such as the area and volume of tumor on preoperative and postresection scans. Phantom scans were used to analyze the accuracy of the program and the program users. User error was estimated at 2%, program error was 4.5%. This methodology is proposed as a means of retrospectively calculating the extent of tumor resection.
Direct thrombosis of aneurysms with cellulose acetate polymer
Authors: Mandai Shinya , Kinugasa Kazushi , Ohmoto Takashi
Published: May 2009

✓ The authors have developed a liquid material for thrombosing aneurysms. This material is a mixture of cellulose acetate polymer and bismuth trioxide dissolved in dimethyl sulfoxide. On contact with blood, the dimethyl sulfoxide diffuses and cellulose acetate polymer forms, which balloons when slowly injected into the blood. The polymer solidifies from surface to core in 5 minutes. Cellulose acetate polymer was injected directly into experimental aneurysms created in 10 dogs; it rapidly hardened in the shape of the aneurysms, completely obliterating them but preserving the parent vessels in all cases. No distal migration of the polymer was seen. The good results of this experimental trial led to a clinical study using a cellulose acetate polymer, as described in Part II.
Tumors of the lateral wall of the cavernous sinus
Authors: El-Kalliny Magdy , van Loveren Harry , Keller Jeffrey T. , Tew John M.
Published: May 2009

✓ The lateral dural wall of the cavernous sinus is composed of two layers, the outer dural layer (dura propria) and the inner membranous layer. Tumors arising from the contents of the lateral dural wall are located between these two layers and are classified as interdural. They are in essence extradural/extracavernous. The inner membranous layer separates these tumors from the venous channels of the cavernous sinus.

Preoperative recognition of tumors in this location is critical for selecting an appropriate microsurgical approach. Characteristics displayed by magnetic resonance imaging show an oval-shaped, smooth-bordered mass with medial displacement but not encasement of the cavernous internal carotid artery. Tumors in this location can be resected safely without entering the cavernous sinus proper by using techniques that permit reflection of the dura propria of the lateral wall (methods of Hakuba or Dolenc).

During the last 5 years, the authors have identified and treated five patients with interdural cavernous sinus tumors, which included two trigeminal neurinomas arising from the first division of the fifth cranial nerve, two epidermoid tumors, and one malignant melanoma presumed to be primary. The pathoanatomical features that make this group of tumors unique are discussed, as well as the clinical and radiological findings, and selection of the microsurgical approach. A more favorable prognosis for tumor resection and cranial nerve preservation is predicted for interdural tumors when compared with other cavernous sinus tumors.
Surgical decompression for symptomatic Chiari II malformation in neonates with myelomeningocele
Authors: Vandertop William P. , Asai Akio , Hoffman Harold J. , Drake James M. , Humphreys Robin P. , Rutka James T. , Becker Laurence E.
Published: May 2009

✓ Between January, 1981, and July, 1991, 17 infants under 1 month of age were admitted to The Hospital for Sick Children with the signs and symptoms of a Chiari II malformation. These patients' presentation included swallowing difficulty (71%), stridor (59%), apneic spells (29%), aspiration (12%), weakness of cry (18%), and arm weakness (53%). Decompression of the Chiari II malformation was performed in all patients, with a time interval between onset of symptoms and surgery ranging from 1 to 121 days. Fifteen patients (88%) remain alive, all of whom have shown a complete recovery. The mean follow-up period in this group of patients was 65 months. Two patients died, one due to respiratory arrest 8 months after decompression and the other because of shunt infection and peritonitis 7 years after decompression. These results support the concept that compressive forces, rather than a primary intrinsic disorder of the brain-stem nuclei, play a crucial etiological role in the development of a symptomatic Chiari II malformation. Early recognition of the symptoms of Chiari II malformation should be followed by immediate decompressive laminectomy in order to promote a prompt and full neurological recovery.
Current prognosis in fetal ventriculomegaly
Authors: Rosseau Gail L. , McCullough David C. , Joseph Amy L.
Published: May 2009

✓ A review of 51 cases referred for evaluation of fetal ventriculomegaly revealed adequate follow-up data in 40 patients. Three of the fetuses were electively aborted and 37 were delivered. There were no cases of deathin utero. Of the 37 infants who were delivered, 26 (70%) were treated with shunt placement for neonatal hydrocephalus. The reasons for nontreatment included: inaccurate diagnosis, resolution of hydrocephalus by the time of delivery, neonatal death, and parental wishes.

Survival time in the 26 shunt-treated patients ranged from 5 days to 14 years (average 4.25 years); five of these patients died within the first 2 weeks of life. Among the 26 treated patients, satisfactory cognitive ability was found in 10 (38%). Of the seven surviving nontreated infants, satisfactory cognitive ability was demonstrated in six (86%).

Children with myelomeningocele displayed cognitive development similar to that in patients without myelomeningocele. The findings suggest that, of patients within uterodiagnosis of ventriculomegaly, approximately one-half survive (4-year average follow-up interval) and 38% of the survivors treated with shunt insertion have normal cognitive development. No subgroup likely to benefit fromin uterotreatment of ventriculomegaly was identified. Associated central nervous system or systemic malformations were identified in 26 (70%) of the 37 who came to delivery. This community-acquired series, not collected from a high-risk obstetrical-perinatal service, may reflect the general experience of the neurosurgeon consulting in such cases.
Detection of recurrent gliomas with quantitative thallium-201/technetium-99m HMPAO single-photon emission computerized tomography
Authors: Carvalho Paulo A. , Schwartz Richard B. , Alexander Eben , Garada Basem M. , Zimmerman Robert E. , Loeffler Jay S. , Holman B. Leonard
Published: May 2009

✓ Deteriorating clinical status after high-dose radiation therapy for high-grade gliomas may be due to radiation changes or may signal recurrent or residual tumor mass. The two conditions cannot be distinguished reliably by computerized tomography (CT) or magnetic resonance (MR) imaging. The authors assessed the ability of sequential thallium-201 chloride (201T1) and technetium-99m hexamethylpropylene amine oxime (99mTc HMPAO) single-photon emission CT (SPECT) to distinguish tumor recurrence from radiation changes after high-dose (≥ 600 cGy) radiation therapy for malignant gliomas. Preoperative tumor/nontumor uptake ratios were analyzed in 32 patients and correlated with the presence of gross tumor at the time of reoperation.

In 12 of 13 patients with 201T1 tumor/scalp ratios of 3.5 or greater, recurrent tumor was present. The authors found 99mTc HMPAO SPECT to be useful for identifying the absence of solid tumor recurrence in patients with low to moderate 201T1 uptake (ratio 1.1 to 3.4) and low perfusion to that site. In 11 of 12 patients with 99mTc HMPAO tumor/cerebellum ratios of 0.50 or less, no recurrent tumor mass was present. Three of seven patients with 201T1 ratios of 3.4 or less and 99mTc HMPAO ratios of 0.51 or more had recurrent tumor found at surgery; thus the test was not predictive in this group. It is concluded that the use of sequential 201T1 and 99mTc HMPAO SPECT accurately identifies the presence of tumor recurrence versus radiation changes in most patients with high-grade astrocytomas who have undergone tumor resection and high-dose radiation therapy.
Posttraumatic cerebral arterial spasm: transcranial Doppler ultrasound, cerebral blood flow, and angiographic findings
Authors: Martin Neil A. , Doberstein Curtis , Zane Cynthia , Caron Michael J. , Thomas Kathleen , Becker Donald P.
Published: May 2009

✓ Thirty patients admitted after suffering closed head injuries, with Glasgow Coma Scale scores ranging from 3 to 15, were evaluated with transcranial Doppler ultrasound monitoring. Blood flow velocity was determined in the middle cerebral artery (MCA) and the intracranial portion of the internal carotid artery (ICA) in all patients. Because proximal flow in the extracranial ICA declines in velocity when arterial narrowing becomes hemodynamically significant, the extracranial ICA velocity was concurrently monitored in 19 patients. To assess cerebral perfusion, cerebral blood flow (CBF) measurements obtained with the intravenous 113Xe technique were completed in 16 patients. Vasospasm, designated as MCA velocity exceeding 120 cm/sec, was found in eight patients (26.7%). Severe vasospasm, defined as MCA velocity greater than 200 cm/sec, occurred in three patients, and was confirmed by angiography in all three. Subarachnoid hemorrhage (SAH) was documented by computerized tomography in five (62.5%) of the eight patients with vasospasm. All cases of severe vasospasm were associated with subarachnoid blood. The time course of vasospasm in patients with traumatic SAH was similar to that found in patients with aneurysmal SAH; in contrast, arterial spasm not associated with SAH demonstrated an uncharacteristically short duration (mean 1.25 days), suggesting that this may be a different type of spasm. A significant correlation (p < 0.05) was identified between the lowest CBF and highest MCA velocity in patients during the period of vasospasm, indicating that arterial narrowing can lead to impaired CBF. Ischemic brain damage was found in one patient who had evidence of cerebral infarction in the territories supplied by the arteries affected by spasm.

These findings demonstrate that delayed cerebral arterial spasm is a frequent complication of closed head injury and that the severity of spasm is, in some cases, comparable to that seen in aneurysmal SAH. This experience suggests that vasospasm is an important secondary posttraumatic insult that is potentially treatable.
Third ventricle germinoma after total removal of intrasellar teratoma
Authors: Czirják Sándor , Pásztor Emil , Slowik Felicia , Szeifert György
Published: May 2009

✓ A unique case is presented of a third ventricle germinoma developing 3 years after total removal of an intrasellar teratoma. The third ventricle germinoma was not considered to be a recurrence or dissemination of the mature intrasellar teratoma but to have been transformed from multicenter germ cells present in the midline of the brain with different temporal development. The relevant literature is reviewed and the problems of management of patients with germ-cell tumors are discussed.
Vagus nerve stimulation for complex partial seizures: surgical technique, safety, and efficacy
Authors: Landy Howard J. , Ramsay R. Eugene , Slater Jeremy , Casiano Roy R. , Morgan Robert
Published: May 2009

✓ Electrical stimulation of the vagus nerve has shown efficacy in controlling seizures in experimental models, and early clinical trials have suggested possible benefit in humans. Eleven patients with complex partial seizures were subjected to implantation of vagus nerve stimulators. Electrode contacts embedded in silicone rubber spirals were placed on the left vagus nerve in the low cervical area. A transcutaneously programmable stimulator module was placed in an infraclavicular subcutaneous pocket and connected to the electrode. One patient required replacement of the system due to electrode fracture. Another patient developed delayed ipsilateral vocal-cord paralysis; the technique was then modified to allow more tolerance for postoperative nerve edema. A third patient showed asymptomatic vocal-cord paresis on immediate postoperative laryngoscopy. Vagus nerve stimulation produces transient vocal-cord dysfunction while the current is on. Nine patients were randomly assigned to receive either high- or low-current stimulation, and seizure frequency was recorded. The high-current stimulation group showed a median reduction in seizure frequency of 27.7% compared to the preimplantation baseline, while the low-current stimulation group showed a median increase of 6.3%. This difference approached statistical significance. The entire population then received maximally tolerable stimulation. The high-current stimulation group showed a further 14.3% reduction, while the low-current stimulation group showed a 25.4% reduction compared to the blinded period. The efficacy of vagus nerve stimulation seemed to depend on stimulus parameters, and a cumulative effect was evident. These results are encouraging, and further study of this modality as an adjunct treatment for epilepsy is warranted.