bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental study of the magnetic stereotaxis system for catheter manipulation within the brain
Authors: Grady M. Sean , Howard Matthew A. , Dacey Ralph G. , Blume Walter , Lawson Michael , Werp Peter , Ritter Rogers C. 
Published: May 2009

Object. The magnetic stereotaxis system (MSS) is a device designed to direct catheter tips through magnetic forces. In this study the authors tested the safety and performance of the MSS in directing catheters through a nonlinear path to obtain biopsy specimens in pig brains.Methods. Sixteen pigs underwent biopsy of the frontal brain region with the aid of an MSS (11 pigs) or a standard stereotactic biopsy tool (five pigs). Surgical preparation consisted of placement of six fiducial markers in the skull and the creation of a burr hole for attachment of a cranial bolt and passage of the biopsy catheter. The pigs underwent magnetic resonance (MR) imaging of the head to define a biopsy target and to plan a nonlinear path. Guided by the MSS, which used nearly real-time fluoroscopic imaging fused to the preoperative MR image, the authors advanced a catheter to the biopsy target. A biopsy tool was passed through the catheter and a tissue sample was obtained. The animals were observed for 3 to 5 days postoperatively, when they were assessed for neurological abnormalities or other signs of morbidity. Actual catheter placement was within 1.5 mm of the planned path to the biopsy site, using a minimum path radius of 30 mm. The registration error associated with the use of the MSS x-ray fluoroscopy and MR imaging averaged 1.7 mm. Tissue disruption caused by the MSS was similar to that of standard stereotactic procedures.Conclusions. The MSS affords accurate and safe guidance of brain catheters in animals. The application tested here, brain biopsy, is one of a number of potential catheter-guided procedures.
Effect of age on cerebral venous circulation disturbances in the rat
Authors: Otsuka Hiroyuki , Nakase Hiroyuki , Nagata Kiyoshi , Ueda Katsuhiro , Kempski Oliver , Sakaki Toshisuke 
Published: May 2009

Object. Mild cerebral venous circulation disturbances (CVCDs) in aged patients are frequently known to cause unexpectedly severe postoperative complications in neurosurgical practice. The object of the present study was to determine whether there are age-related differences involved in vulnerability to CVCDs.Methods. Thirty-eight male Wistar rats were used. A single cortical vein with a 100-µm diameter was occluded photochemically by using rose bengal dye and fiberoptic illumination in young (Group Y, 19 animals aged 10–14 weeks) and aged (Group A, seven animals aged 80–100 weeks) rats. Five young and seven aged animals served as sham-operated controls. Regional cerebral blood flow (rCBF) was determined from local CBF, which was measured at 25 (5 × 5) identical locations, with the occluded vein located central to the scanning field, by using a laser Doppler scanning technique every 15 minutes for 90 minutes after venous occlusion. The cerebral venous flow pattern was examined using fluorescence angiography until 90 minutes after occlusion. Histological specimens were examined 24 hours after occlusion. In Group Y, rCBF did not change significantly after venous occlusion. However, in Group A, rCBF decreased rapidly beginning 15 minutes after occlusion. Significant intergroup differences were observed 30, 60, and 90 minutes after occlusion. Venous flow arrest, which resulted in venous infarct, was observed on angiography 90 minutes after occlusion in two (10.5%) of 19 young and six (85.7%) of seven aged rats. The venous thrombus in Group A rats was significantly larger than that in Group Y rats 90 minutes after occlusion. Venous infarction was seen in all aged rats (100%) and in six young rats (31.6%); the infarct size, expressed as a percentage of the size of the ipsilateral hemisphere, was significantly larger in aged rats than in young rats.Conclusions. This study demonstrated an age-related increase in the rate and size of venous infarct following vein occlusion, suggesting that the greater vulnerability to CVCDs in the aged brain might be attributed to early and extensive hypoperfusion of circumscribed brain areas drained by the occluded vein. The larger thrombus formation in aged animals indicates that a shift in the thrombogenetic/thrombolytic equilibrium is responsible for the observed effect.
Medulloblastomas with extensive posttherapy neuronal maturation
Authors: Cai Dan X. , Mafra Manuela , Schmidt Robert E. , Scheithauer Bernd W. , Park Tae Sung , Perry Arie 
Published: May 2009

✓ The authors report on two patients with classic medulloblastoma, each of whom underwent extensive therapy-associated neuronal maturation. The first patient presented at 3 months of age with hydrocephalus caused by a 5-cm tumor in the cerebellar vermis. He underwent a gross-total resection of a desmoplastic medulloblastoma. No mature elements were identified. Despite adjuvant chemotherapy, a 1.5-cm recurrent tumor developed 6 months later. Sections from the subtotally resected tumor demonstrated exclusively mature neuronal elements, ranging from neurocytes to ganglion cells. Four months later, a second recurrent tumor was resected. The specimen collected this time demonstrated classic medulloblastoma morphological characteristics. The patient was subsequently treated with radiation therapy, which seemed to have an effect; however, the tumor eventually progressed and the patient died. The second patient presented at 3 years of age with a midline medulloblastoma and was treated with subtotal resection, radiation therapy, and chemotherapy. Although the tumor remained stable on radiographic imaging, a second resection was performed 8 years later to alleviate hydrocephalus. Histological examination revealed predominantly small mature neurons with scattered ganglion cells and extensive calcification. No adjuvant therapy was given and the patient is alive and well as of his last follow-up examination.The mature neuronal neoplasms resected in both patients demonstrated negligible proliferative indices and stained appropriately with neuronal immunohistochemical markers. The smaller neuronal population resembled those of a central neurocytoma and medullocytoma/cerebellar neurocytoma. Analogous to neuroblastoma, our cases suggest that adjuvant therapy can induce extensive or complete neuronal maturation in medulloblastoma. Additional cases must be studied to determine the prognostic significance of this rare phenomenon.
Virtual image navigation: a new method to control intraoperative bleeding in neuroendoscopic surgery
Authors: Scholz Martin , Fricke Britta , Tombrock Stephan , Hardenack Markus , Schmieder Kirsten , von Düring Monika , Konen Wolfgang , Harders Albrecht 
Published: May 2009

✓ In this neuroendoscopic study the authors tested the newly developed “red-out module” of their visual navigation system that enables the neurosurgeon to achieve hemostasis if total visualization is lost due to hemorrhage (“red out”) within the visual field. An optical position measurement system connected to the endoscope guarantees that digitized endoscopic images are coupled with the accurate endoscopic position. Computerized images are simultaneously stored with their respective position data, and this creates a virtual anatomical landscape. The system was tested in in vivo bleeding conditions in a rat model. Artificial endoscopic cavities were created in the inguinal, pelvic, and jugular regions in rats to imitate the conditions of the human ventricular system.Two experimental settings were tested: Technique I, in which a computer landmark has been previously determined at the point where the vessel will be lesioned; and Technique II, in which a landmark has been previously set in the surrounding area of the vessel. Immediately after hemorrhage obscures the visual field (red out), the computer automatically displays the virtual images on a separate monitor. The previously set landmarks and the graphic overlay of the coagulation fiber enable the surgeon to navigate within the operative field based on the virtual images and to perform coagulation at the site of the lesion. A total of 175 vessels were coagulated: 43 arteries and 132 veins. In using Technique I, 130 (90.9%) of 143 vessels and in using Technique II, 26 (81.2%) of 32 arteries were successfully coagulated. The authors' data revealed that virtual image guidance has the potential to be a helpful tool in neuroendoscopy.
Natural history of unruptured intracranial aneurysms: probability of and risk factors for aneurysm rupture
Authors: Juvela Seppo , Porras Matti , Poussa Kristiina 
Published: May 2009

Object. The authors conducted a study to investigate the long-term natural history of unruptured intracranial aneurysms and the predictive risk factors determining subsequent rupture in a patient population in which surgical selection of cases was not performed.Methods. One hundred forty-two patients with 181 unruptured aneurysms were followed from the 1950s until death or the occurrence of subarachnoid hemorrhage or until the years 1997 to 1998. The annual and cumulative incidence of aneurysm rupture as well as several potential risk factors predictive of rupture were studied using life-table analyses and Cox's proportional hazards regression models including time-dependent covariates.The median follow-up time was 19.7 years (range 0.8–38.9 years). During 2575 person-years of follow up, there were 33 first-time episodes of hemorrhage from previously unruptured aneurysms, for an average annual incidence of 1.3%. In 17 patients, hemorrhage led to death. The cumulative rate of bleeding was 10.5% at 10 years, 23% at 20 years, and 30.3% at 30 years after diagnosis. The diameter of the unruptured aneurysm (relative risk [RR] 1.11 per mm in diameter, 95% confidence interval [CI] 1–1.23, p = 0.05) and patient age at diagnosis inversely (RR 0.97 per year, 95% CI 0.93–1, p = 0.05) were significant independent predictors for a subsequent aneurysm rupture after adjustment for sex, hypertension, and aneurysm group. Active smoking status at the time of diagnosis was a significant risk factor for aneurysm rupture (RR 1.46, 95% CI 1.04–2.06, p = 0.033) after adjustment for size of the aneurysm, patient age, sex, presence of hypertension, and aneurysm group. Active smoking status as a time-dependent covariate was an even more significant risk factor for aneurysm rupture (adjusted RR 3.04, 95% CI 1.21–7.66, p = 0.02).Conclusions. Cigarette smoking, size of the unruptured intracranial aneurysm, and age, inversely, are important factors determining risk for subsequent aneurysm rupture. The authors conclude that such unruptured aneurysms should be surgically treated regardless of their size and of a patient's smoking status, especially in young and middle-aged adults, if this is technically possible and if the patient's concurrent diseases are not contraindications. Cessation of smoking may also be a good alternative to surgery in older patients with small-sized aneurysms.
Predictors of neuropsychological outcome in patients following microelectrode-guided pallidotomy for Parkinson's disease
Authors: Obwegeser Alois A. , Uitti Ryan J. , Lucas John A. , Witte Robert J. , Turk Margaret F. , Wharen Robert E. 
Published: May 2009

Object. The authors studied neuropsychological performance following microelectrode-guided posteroventral pallidotomy in patients with Parkinson's disease (PD) and evaluated correlations with presurgical and surgical factors.Methods. Neuropsychological changes 3 months (43 patients) and 12 months (27 patients) after microelectrode-guided pallidotomy for PD are reported in a series of 44 consecutive patients with the disease, who improved neurologically, as measured by the Unified Parkinson's Disease Rating Scale (UPDRS) in both the “off” (p < 0.001) and best “on” (p < 0.001) states.Findings of the vocabulary subtest of the Wechsler Adult Intelligence Scale—Revised (p < 0.01), Letter Fluency (p < 0.001), Verbal Fluency for semantic categories (p < 0.001), and the Wisconsin Card Sorting Test (p < 0.01) showed a significant decline in neuropsychological performance in patients 3 months after undergoing left-sided pallidotomy. Impairment in the language domain (semantic fluency) persisted at the 12-month follow-up examination (p < 0.01). Visual memory improved after right-sided pallidotomies (p < 0.01 after 3 months), with a nonsignificant trend toward persistent improvement 1 year postsurgery (p < 0.02 after 12 months). Preoperative semantic fluency was influenced by patient age (p < 0.001) and by the width of the third ventricle (p < 0.05), as measured by magnetic resonance imaging.A regression model revealed that semantic fluency 3 months postoperatively was significantly affected by the baseline score (p < 0.001), side of surgery (p < 0.001), handedness (p < 0.01), and patient age (p < 0.05). However, postoperative lesion volume, lesion location, number of tracks, number of lesions, distance from anatomical landmarks, or UPDRS score did not significantly contribute to neuropsychological outcome.Conclusions. Neuropsychological changes in a cohort of patients with PD who underwent pallidotomy and experienced excellent clinical benefits and minimum postoperative complications, emphasize the importance of neuropsychological examinations and further investigation of predictive factors.
Maturation-dependent response of the piglet brain to scaled cortical impact
Authors: Duhaime Ann-Christine , Margulies Susan S. , Durham Susan R. , O'Rourke Maureen M. , Golden Jeffrey A. , Marwaha Sunil , Raghupathi Ramesh 
Published: May 2009

Object. The goal of this study was to investigate the relationship between maturational stage and the brain's response to mechanical trauma in a gyrencephalic model of focal brain injury. Age-dependent differences in injury response might explain certain unique clinical syndromes seen in infants and young children and would determine whether specific therapies might be particularly effective or even counterproductive at different ages.Methods. To deliver proportionally identical injury inputs to animals of different ages, the authors have developed a piglet model of focal contusion injury by using specific volumes of rapid cortical displacement that are precisely scaled to changes in size and dimensions of the growing brain. Using this model, the histological response to a scaled focal cortical impact was compared at 7 days after injury in piglets that were 5 days, 1 month, and 4 months of age at the time of trauma. Despite comparable injury inputs and stable physiological parameters, the percentage of hemisphere injured differed significantly among ages, with the youngest animals sustaining the smallest lesions (0.8%, 8.4%, and 21.5%, for 5-day-, 1-month-, and 4-month-old animals, respectively, p = 0.0018).Conclusions. These results demonstrate that, for this particular focal injury type and severity, vulnerability to mechanical trauma increases progressively during maturation. Because of its developmental and morphological similarity to the human brain, the piglet brain provides distinct advantages in modeling age-specific responses to mechanical trauma. Differences in pathways leading to cell death or repair may be relevant to designing therapies appropriate for patients of different ages.
Brain abscess related to metal fragments 47 years after head injury
Authors: Lee June-Ho , Kim Dong Gyu 
Published: May 2009

✓ The authors report a case of symptomatic brain abscess in a 51-year-old man who presented with personality changes and generalized seizures. He had survived a grenade explosion injury during the Korean War 47 years previously. Computerized tomography scanning revealed multiple conglomerate rim-enhancing lesions and metallic foreign bodies in the right frontal lobe. The mass was totally removed and Pseudomonas aeruginosa was isolated from microbial cultures.Retained foreign bodies in the brain, whether bone or metal, should be removed at the time of injury if at all possible. If this cannot be accomplished, patients with such retained foreign bodies should be carefully monitored for life.
Use of an intracranial near-infrared probe for localization during stereotactic surgery for movement disorders
Authors: Giller Cole A. , Johns Maureen , Liu Hanli 
Published: May 2009

✓ Localization of targets during stereotactic surgery is frequently accomplished by identification of the boundaries between the gray matter of various nuclei and the surrounding white matter. The authors describe an intracranial probe developed for this purpose, which uses near-infrared (NIR) light.The probe fits through standard stereotactic holders and emits light at its tip. The scattered light is detected and analyzed by a spectrometer, with the slope of the trailing portion of the reflectance curve used as the measurement value.Near-infrared readings were obtained during 27 neurosurgical procedures. The first three operations were temporal lobectomies, with values obtained from tracks in the resected specimen and resection bed. In the next five procedures, the probe was inserted stereotactically to a depth of 1 to 2 cm with measurements obtained every 1 mm. The probe was then used in 19 stereotactic procedures for movement disorders, obtaining measurements every 0.5 to 1 mm to target depths of 6 to 8 cm to interrogate subcortical structures. The NIR signals were correlated to distances beneath the cortical surface measured on postoperative computerized tomography or magnetic resonance imaging by using angle correction and three-dimensional reconstruction techniques.The NIR values for white and gray matter obtained during the lobectomies were significantly different (white matter 2.5 ± 0.37, gray matter 0.82 ± 0.23 mean ± standard deviation). The NIR values from the superficial stereotactic tracks showed initial low values corresponding to cortical gray matter and high values corresponding to subcortical white matter.There was good correlation between the NIR signals and postoperative imaging in the 19 stereotactic cases. Dips due to adjacent sulci, a plateau of high signal due to subcortical white matter, a dip in the NIR signal during passage through the ventricle, dips due to the caudate nucleus, and peaks due to the white matter capsule between ventricle and thalamus were constant features. The putamen—capsule boundary and the lamina externa and interna of the globus pallidus could be distinguished in three cases. Elevated signals corresponding to the thalamic floor were seen in 10 cases. Nuances such as prior lesions and nonspecific white matter changes were also detected. There was no incidence of morbidity associated with use of the probe. Data acquisition was straightforward and the equipment required for the studies was inexpensive.The NIR probe described in this article seems to be able to detect gray—white matter boundaries around and within subcortical structures commonly encountered in stereotactic functional neurosurgery. This simple, inexpensive method deserves further study to establish its efficacy for stereotactic localization.
Do women fare worse: a metaanalysis of gender differences in traumatic brain injury outcome
Authors: Farace Elana , Alves Wayne M. 
Published: May 2009

Object. The purpose of this metaanalysis was to investigate possible gender differences in traumatic brain injury (TBI) sequelae. The case fatality rates in patients after TBI have previously been shown to be significantly higher in women as compared with men.Methods. A quantitative review of published studies of TBI outcome revealed eight studies (20 outcome variables) of TBI, in which outcome was reported separately for men and women.Conclusions. Outcome was worse in women than in men for 85% of the measured variables, with an average effect size of −0.15. Although clinical opinion is often that women tend to experience better outcomes than men after TBI, the opposite pattern was suggested in the results of this metaanalysis. However, this conclusion is limited by the fact that, in only a small percentage of the total published reports on TBI outcome, was outcome described separately for each sex. A careful, prospective study of sex differences in TBI outcome is clearly needed.
Intraoperative endovascular treatment as an adjunct to microsurgical clipping of paraclinoid aneurysms
Authors: Ng Puay-Yong , Huddle Daniel , Gunel Murat , Awad Issam A. 
Published: May 2009

Object. The endovascular procedure can provide proximal control, suction decompression, and prompt intraoperative angiography during microsurgical clipping of aneurysms of the paraclinoid segment of the internal carotid artery (ICA). The authors assess the safety and feasibility of this method in 24 consecutive cases.Methods. Frontotemporal craniotomy and radical pterionectomy were performed with the patient's head immobilized in a radiolucent frame while femoral artery catheterizaton was achieved. Before dural opening, a balloon catheter with a coaxial lumen was positioned and tested in the ICA, after which microsurgical exposure was completed, including intradural clinoid drilling and optic canal decompression. Trapping of the lesion was achieved by inflating the balloon and placing a temporary clip beyond the aneurysm neck. The catheter was gently aspirated to achieve suction decompression and to facilitate clip application. Intraoperative digital subtraction angiography was then performed.Twenty-two aneurysms were larger than 10 mm, and 11 of them were giant. Six patients presented with subarachnoid hemorrhage and nine with visual symptoms. Balloon occlusion and suction decompression were performed in 16 cases (67%), and proximal control alone in 1 case. Intraoperative angiography was performed in every case. Subsequent clip readjustment was necessary in seven cases, including three cases of residual aneurysm filling and four of ICA compromise. Complete aneurysm obliteration was achieved in 20 cases, and greater than 90% obliteration in 22. One major infarct likely related to catheter thromboembolism was found. There were no instances of visual deterioration or other complications attributable to the endovascular procedure.Conclusions. The endovascular method allows safe and reliable proximal control, suction decompression, and intraoperative angiography in microsurgical treatment of large paraclinoid aneurysms.
Posture-related changes in the pressure environment of the ventriculoperitoneal shunt system
Authors: Kajimoto Yoshinaga , Ohta Tomio , Miyake Hiroji , Matsukawa Masanori , Ogawa Daiji , Nagao Kohji , Kuroiwa Toshihiko 
Published: May 2009

Object. The purpose of this study is to clarify the whole pressure environment of the ventriculoperitoneal (VP) shunt system in patients with successfully treated hydrocephalus and to determine which factor of the pressure environment has a preventive effect on overdrainage.Methods. Thirteen patients with hydrocephalus who had been treated with VP shunt therapy by using a Codman– Hakim programmable valve without incidence of overdrainage were examined. The authors evaluated intracranial pressure (ICP), intraabdominal pressure (IAP), hydrostatic pressure (HP), and the perfusion pressure (PP) of the shunt system with the patients both supine and sitting.With patients supine, ICP, IAP, and HP were 4.6 ± 3 mm Hg, 5.7 ± 3.3 mm Hg, and 3.3 ± 1 mm Hg, respectively. As a result, the PP was only 2.2 ± 4.9 mm Hg. When the patients sat up, the IAP increased to 14.7 ± 4.8 mm Hg, and ICP decreased to −14.2 ± 4.5 mm Hg. The increased IAP and decreased ICP offset 67% of the HP (42.9 ± 3.5 mm Hg), and consequently the PP (14 ± 6.3 mm Hg) corresponded to only 33% of HP.Conclusions. The results observed in patients indicated that IAP as well as ICP play an important role in VP shunt therapy and that the increased IAP and the decreased ICP in patients placed in the upright position allow them to adapt to the siphoning effect and for overdrainage thereby to be avoided.