bluuebunny/crossref_metadata_2025 huggingface dataset:
Malignant peripheral nerve sheath tumors in the setting of segmental neurofibromatosis
Authors: Schwarz Jacob , Belzberg Allan J.
Published: May 2009

✓ Approximately 100 cases of segmental neurofibromatosis (NF5) have been reported in the recent literature. Patients with NF5 present with café-au-lait macules, freckles, and/or neurofibromas limited to one or adjacent dermatomes. Neurofibromas arising in NF5 have been uniformly considered to be benign; patients were thought to have an excellent prognosis without the risk of developing malignant peripheral nerve sheath tumors (PNSTs), which are characteristic in patients with the generalized form of this disease, von Recklinghausen's NF. In this report the authors detail the first observations of malignant PNSTs in two patients with NF5. Indications for surgical removal of a neurofibroma in a patient with NF include pain, neurological impairment, compression of adjacent structures, cosmetic disfigurement, and rapid tumor growth suggestive of malignant degeneration. Surgical indications are similar for patients with NF5. All patients with neurofibromas should be considered at risk for malignant degeneration.
Long-term follow up of progesterone receptor status in benign meningioma: a prognostic indicator of recurrence?
Authors: Fewings Paul E. , Battersby Robert D. E. , Timperley Walter R.
Published: May 2009

Object. A long-term prospective analysis of patients with benign meningioma was undertaken to determine whether progesterone receptor (PR) status of the excised tumor has any influence on recurrence.

Methods. Between 1983 and 1985, a total of 62 meningiomas in 53 patients (age range 19–79 years, mean age 55.6 years) were studied for clinical, histological, and pathological characteristics, including hormone receptor status and DNA features. Progesterone receptor status was quantified by cryostat section assay, and then factors affecting recurrence were analyzed. During 1997 all case records were reviewed to determine whether tumor had recurred in any patient, and PR status was correlated with tumor recurrence.

Of the 62 tumors, 60 were benign, and of the benign tumors 29 (48%) were PR positive. Patients harboring 14 of the 60 benign tumors were lost to follow up. Of the 46 tumors included in the final analysis, 13 were recurrent (all within 5 years) and 33 were nonrecurrent. Of the 33 nonrecurrent tumors, 14 had not recurred 5 to 10 years postresection and 19 had not recurred after more than 10 years. Chi-square analysis of the results did not show an association between recurrence and patient's sex, extent of resection, histological subtype, or tumor site but did show an association between recurrence and PR negativity (p = 0.013).

Conclusions. The results indicate that benign meningiomas that are PR positive are less likely to recur, a finding that has prognostic and therapeutic implications.
Locomotion and proliferation of glioblastoma cells in vitro: statistical evaluation of videomicroscopic observations
Authors: Hegedüs Balás , Czirók András , Fazekas Ilona , Bábel Tamás , Madarász Emília , Vicsek Tamás
Published: May 2009

Object. The motility and doubling of human glioblastoma cells were investigated by means of statistical evaluation of large sets of data obtained using computer-aided videomicroscopy.

Methods. Data were obtained on cells in four established glioblastoma cell lines and also on primary tumor cells cultured from fresh surgical samples. Growth rates and cell cycle times were measured in individual microscopic fields. The averages of cell cycle time and the duplication time for the recorded cell populations were 26.2 ± 5.6 hours and 38 ± 4 hours, respectively. With these parameters, no significant differences among the cell lines were revealed. Also, there was no correlation in the cell cycle time of a parent cell and its progeny in any of the cultures.

Statistical analysis of cell locomotion revealed an exponential distribution of cell velocities and strong fluctuations in individual cell velocities across time. The average velocity values ranged from 4.2 to 27.9 µm/hour. In spite of the uniform histopathological classification of the four tumors, each cell line produced by these tumors displayed distinct velocity distribution profiles and characteristic average velocity values. A comparison of recently established primary cultures with cell lines that had propagated multiple times indicated that cells derived from different tumors sustain their characteristic locomotor activity after several passages.

Conclusions. It can be inferred from the data that statistical evaluation of physical parameters of cell locomotion can provide additional tools for tumor diagnosis.
Primary meningeal melanocytoma of the pineal region
Authors: Czirják Sándor , Vitanovic Dusan , Slowik Felicia , Magyar Attila
Published: May 2009

✓ A unique case of a meningeal melanocytoma located in the pineal region is presented. This 48-year-old man presented with a round pineal region tumor that caused triventricular hydrocephalus and exhibited slow clinical progression. During surgery a black encapsulated tumor was found and totally removed. On histopathological examination, the tumor proved to be a meningeal melanocytoma. In this report cell culture data are presented and the relevant literature is reviewed. The problems of histopathological diagnosis and management of patients with melanocytomas are also discussed.
Intracranial hypotension without meningeal enhancement on magnetic resonance imaging
Authors: Schievink Wouter I. , Tourje James
Published: May 2009

✓ Meningeal enhancement on magnetic resonance (MR) imaging is considered the hallmark radiological feature of intracranial hypotension. The authors report on a patient who exhibited progressively symptomatic intracranial hypotension due to a lumbar cerebrospinal fluid (CSF) leak, but in whom MR imaging demonstrated no pachymeningeal enhancement.

This 24-year-old man presented with a 6-week history of progressive orthostatic headaches that were associated with photo- and phonophobia. Four weeks before the onset of the headaches, the patient had undergone a lumbar laminectomy. Brain MR images revealed subdural fluid collections and brain sagging; however, meningeal enhancement was not present. Myelography demonstrated a CSF leak at the site of the laminectomy. At surgery, a large dural tear was repaired. The patient recovered well from the surgery, with complete resolution of his headaches.

The absence of meningeal enhancement on MR imaging does not exclude a diagnosis of symptomatic intracranial hypotension.
Tethered cord syndrome in children with anorectal malformations
Authors: Muthukumar Natarajan , Subramaniam Bhuvaneswari , Gnanaseelan Thangaraj , Rathinam Ramesh , Thiruthavadoss Appaswamy
Published: May 2009

Object. Anorectal malformations are known to be associated with neurological deficits, which may contribute to the disability suffered by patients with these malformations. This study was undertaken to determine the incidence and pattern of sacral abnormalities in children with anorectal malformations, the incidence and nature of the neurological deficits, and the incidence and nature of operable intraspinal abnormalities in patients with this condition.

Methods. Neurological evaluation was performed in 81 children with anorectal malformations. Plain x-ray films were obtained to identify the presence of sacral abnormalities. The patients with neurological deficits were evaluated for the presence of operable intraspinal anomalies, and when such anomalies were identified, correction of the same was undertaken. In 21% of these children radiographic evidence of sacral abnormalities was shown. Fifteen percent of patients harbored neurological deficits, and 10% harbored operable intraspinal anomalies. In addition, one patient had split notochord syndrome. Patients with operable intraspinal anomalies underwent surgical correction, with resultant neurological improvement.

Conclusions. Bone abnormalities of the sacrum, neurological deficits, and operable intraspinal lesions are not uncommon in children with anorectal malformations. Because the neurological deficits can contribute to the disability suffered by these individuals, we recommend routine screening of patients with anorectal malformations and neurological deficits and/or sacral abnormalities for the early identification and treatment of potentially correctable intraspinal lesions.
Fibroblast growth factor receptor 3 mutation in nonsyndromic coronal synostosis: clinical spectrum, prevalence, and surgical outcome
Authors: Renier Dominique , El Ghouzzi Vincent , Bonaventure Jacky , Le Merrer Martine , Lajeunie Elizabeth
Published: May 2009

Object. A recurrent point mutation in the fibroblast growth factor receptor 3 gene that converts proline 250 into arginine has been reported recently in cases of apparently nonsyndromic coronal craniosynostosis. The goal of the present study was to examine the phenotype of patients in whom this mutation was present, to determine the prevalence of the condition, and to assess the functional and the morphological outcome of the surgically treated patients.

Methods. A DNA analysis was performed in 103 children suffering from apparently isolated coronal synostosis, 41 of whom had bilateral and 62 of whom had unilateral disease. There were 31 boys and 72 girls in the study group. Sixty cases were sporadic and 43 were familial; the 43 familial cases arose in 33 unrelated families. The mutation was found in seven (12%) of 60 sporadic cases and in 24 (73%) of the 33 families. The functional and morphological results were assessed in all surgically treated patients who had at least 1 year of follow up and who were at least 3 years of age at the time of assessment. A comparison was made between patients with the mutation and those without.

Conclusions. The most typical presentation was seen in girls and consisted of a bicoronal synostosis resulting in a severe brachycephaly associated with mild hypertelorism and marked bulging of the temporal fossae, which resulted in a huge enlargement of the upper part of the face. The most frequently associated extracranial anomaly was brachydactyly, identified either clinically or radiologically. Based on the proportion of bilateral and unilateral coronal synostoses, the present data indicate that the mutation is associated with more severe cases and that girls with the mutation are more severely affected than boys. The functional and morphological results were worse in patients in whom the mutation was present as compared with those in whom it was not.
Neuroscience education of undergraduate medical students. Part I: role of neurosurgeons as educators
Authors: Resnick Daniel K.
Published: May 2009

Object. Economic, demographic, and political pressures have mandated that medical schools increase the number of primary care physicians. The goal of this study was to determine the nature of the average medical student's exposure to neurosurgical issues.

Methods. Surveys were sent to every neurosurgical program director in the United States and to the dean of every medical school in North America, querying the extent of neurosurgical involvement in medical student education. Specifically, the respondents were asked how medical students were educated about the management of low-back pain and radiculopathy, carotid artery disease, head and spine trauma, and headache.

Survey results were obtained from 65 (67%) of 97 neurosurgery program directors and from 57 (40%) of 143 medical school deans. Only one program in North America reported having a required neurosurgical rotation for all medical students, and just over 50% (29 of 57 deans and 34 of 65 program directors) reported that neurosurgery was an option in a required neuroscience or surgical subspecialty course. Neurosurgeons were not listed among the top three sources for medical student education in the topics of low-back pain and radiculopathy or carotid artery disease. Neurosurgeons were the most frequently cited source of education regarding head and spinal injuries, despite the fact that the majority of medical schools do not have any required medical student exposure to neurosurgery.

Conclusions. With rare exceptions, neurosurgeons are not significantly involved in the education of medical students concerning the management of common neurosurgical issues. As a result, most emerging primary care physicians are taught about these issues by other specialists or not at all. The implications of this situation are discussed.
Neuroscience education of undergraduate medical students. Part II: outcome improvement
Authors: Resnick Daniel K. , Ramirez Lincoln F.
Published: May 2009

Object. Because of political and economic pressures, primary care physicians are now charged with greater responsibility for the care of patients with disease processes definitively managed by neurosurgeons. The goal of this study was to establish the feasibility and efficacy of a neurosurgical curriculum designed to teach future primary care physicians about these diseases.

Methods. A compact, seven-lecture curriculum was developed to teach 3rd-year medical students about degenerative spine disease, stroke, tumor- and hydrocephalus-related raised intracranial pressure, head and spine injury, and subarachnoid hemorrhage. This curriculum was given as part of a 6-week pilot course that included neurology, neurosurgery, ophthalmology, and rehabilitation medicine components. This course was administered to two groups of 18 medical students, and an examination was administered at the end of the pilot course. The same examination was administered to an additional 19 students immediately after their completion of the neurology course currently required.

Students enrolled in the pilot neuroscience course performed significantly better (p < 0.001) on the examination than those who had completed the standard neurology course. Striking improvements were noted in the recognition and management of head injury, hydrocephalus, and radiculopathy.

Conclusions. Inclusion of a short neurosurgery-related curriculum in a combined neuroscience course significantly improved student performance on an examination focusing on the recognition and management of common neurosurgical disorders. Because primary care physicians are responsible for the initial recognition and management of these disorders, the knowledge gained may lead to improved patient care.
Neuroprotection by the stable nitroxide Tempol during reperfusion in a rat model of transient focal ischemia
Authors: Rak Ramin , Chao Daniel L. , Pluta Ryszard M. , Mitchell James B. , Oldfield Edward H. , Watson Joe C.
Published: May 2009

Object. The use of thrombolytic agents in the treatment of stroke has yielded surprisingly modest success, possibly because of reperfusion injury mediated by reactive oxygen species (ROS). Therefore, scavenging ROS may be of therapeutic value in the treatment of stroke. Nitroxides are low-weight superoxide dismutase mimics, which allows them to act as cell-permeable antioxidants. In this study the nitroxide 4-hydroxy-2,2,6,6,-tetramethylpiperidine-1-oxyl (Tempol) is investigated to determine its ability to reduce reperfusion injury.

Methods. Male Sprague—Dawley rats weighing between 280 g and 350 g underwent middle cerebral artery occlusion with an intraluminal suture for 60 minutes. Regional cerebral blood flow, blood pressure, cerebral temperature, and rectal temperature were monitored during the procedure. After reperfusion, the animals were randomized to groups receiving blinded intravenous administration of either Tempol (10 mg/kg; eight animals) or vehicle (eight animals) over the first 20 minutes of reperfusion (Study I). In a second study to determine dose dependency, animals were randomized to groups receiving Tempol (20 mg/kg; eight animals), low-dose Tempol (5 mg/kg; eight animals), or vehicle (eight animals; Study II). The rats were killed after 4 hours of reperfusion, and brain sections were stained with 2,3,5 triphenyltetrazolium chloride. Infarct volumes were measured using digital imaging.

Animals receiving Tempol had significantly reduced infarct volumes at doses of 20 mg/kg and 10 mg/kg compared with controls (49.01 ± 18.22% reduction [p = 0.003] and 47.47 ± 34.57 [p = 0.02], respectively). No significant differences in the physiological variables measured were observed between groups.

Conclusions. Tempol provides significant neuroprotection after reperfusion in a rat model of transient focal ischemia. These results support the importance of ROS in reperfusion injury and encourage further study of this molecule as a therapeutic agent following thrombolysis.
Genetic reflection of glioblastoma biopsy material in xenografts: characterization of 11 glioblastoma xenograft lines by comparative genomic hybridization
Authors: Jeuken Judith W. M. , Sprenger Sandra H. E. , Wesseling Pieter , Bernsen Hans J. J. A. , Suijkerbuijk Ron F. , Roelofs Femke , Macville Merryn V. E. , Gilhuis H. Jacobus , van Overbeeke Jacobus J. , Boerman Rudolf H.
Published: May 2009

Object. Human tumors implanted as subcutaneous xenografts in nude mice are widely used for the study of tumor biology and therapy. Validation of these models requires knowledge of the genetic makeup of the xenografts. The aim of this study was to establish whether chromosomal imbalances in 11 xenograft lines derived from human glioblastomas multiforme (x-GBMs) are similar to those found in GBM biopsy samples. The authors also studied genetic stability during serial passaging of three xenograft lines.

Methods. Chromosomal imbalances in x-GBMs were detected using comparative genomic hybridization (CGH). The authors compared the CGH results in x-GBMs with those in the original GBMs (o-GBMs) that were used to establish three of the xenograft lines and with the GBM biopsy results reported in the literature (l-GBMs). In three xenograft lines two different passages were analyzed.

Conclusions. The results show that the chromosomal imbalances in x-GBMs are similar to those in o-GBMs and l-GBMs, indicating that the GBM xenograft lines used were valid models from a genetic point of view. The CGH analysis of two different passages of three xenograft lines indicates that x-GBMs (like l-GBMs) show intratumoral genetic heterogeneity and do not acquire chromosomal imbalances as a result of serial passaging.
Promotion of survival and regeneration of nigral dopamine neurons in a rat model of Parkinson's disease after implantation of embryonal carcinoma—derived neurons genetically engineered to produce glial cell line—derived neurotrophic factor
Authors: Nakao Naoyuki , Yokote Hideyuki , Nakai Kunio , Itakura Toru
Published: May 2009

Object. The P19 embryonal carcinoma—derived cell line consists of undifferentiated multipotential cells, which irreversibly differentiate into mature neurons after exposure to retinoic acid (RA). In the present study, the authors genetically engineered P19 cells to produce glial cell line—derived neurotrophic factor (GDNF), and grafted the cells in a rat model that had been rendered parkinsonian.

Methods. Undifferentiated P19 cells were grown in vitro and transduced with GDNF complementary DNA. The level of GDNF released from the transduced cells was measured using an enzyme-linked immunosorbent assay, and its neurotrophic activities were assessed by testing the effects on rat embryonic dopamine (DA) neurons in culture. After having been exposed to RA for 48 hours and allowed to differentiate into postmitotic neurons, the GDNF gene—transduced cells were implanted into the midbrain of immunosuppressed rats. A unilateral nigrostriatal lesion was then induced by intrastriatal infusions of 6-hydroxydopamine. Immunohistochemical analyses performed 4 weeks postgrafting revealed that the GDNF-producing cells expressed several neuronal markers without evidence of overgrowth. The grafts expressed GDNF protein and prevented the death of nigral DA neurons. Furthermore, the GDNF-producing cells implanted 4 weeks after nigrostriatal lesions restored the expression of tyrosine hydroxylase in injured DA neurons and induced their dendritic sprouting.

Conclusions. The results indicate that the P19 cell line transduced with the GDNF gene can stably secrete functional levels of GDNF, even after being converted to postmitotic neurons. Because it is has been established that GDNF exerts trophic effects on DA neurons, the means currently used to deliver GDNF into the brain could be a viable strategy to prevent the death of nigral DA neurons in cases of Parkinson's disease.
Arteries of the insula
Authors: Türe Uğur , Yaşargil M. Gazi , Al-Mefty Ossama , Yaşargil Dianne C. H.
Published: May 2009

Object. The insula is located at the base of the sylvian fissure and is a potential site for pathological processes such as tumors and vascular malformations. Knowledge of insular anatomy and vascularization is essential to perform accurate microsurgical procedures in this region.

Methods. Arterial vascularization of the insula was studied in 20 human cadaver brains (40 hemispheres). The cerebral arteries were perfused with red latex to enhance their visibility, and they were dissected with the aid of an operating microscope.

Arteries supplying the insula numbered an average of 96 (range 77–112). Their mean diameter measured 0.23 mm (range 0.1–0.8 mm), and the origin of each artery could be traced to the middle cerebral artery (MCA), predominantly the M2 segment. In 22 hemispheres (55%), one to six insular arteries arose from the M1 segment of the MCA and supplied the region of the limen insulae. In an additional 10 hemispheres (25%), one or two insular arteries arose from the M3 segment of the MCA and supplied the region of either the superior or inferior periinsular sulcus. The insular arteries primarily supply the insular cortex, extreme capsule, and, occasionally, the claustrum and external capsule, but not the putamen, globus pallidus, or internal capsule, which are vascularized by the lateral lenticulostriate arteries (LLAs). However, an average of 9.9 (range four–14) insular arteries in each hemisphere, mostly in the posterior insular region, were similar to perforating arteries and some of these supplied the corona radiata. Larger, more prominent insular arteries (insuloopercular arteries) were also observed (an average of 3.5 per hemisphere, range one–seven). These coursed across the surface of the insula and then looped laterally, extending branches to the medial surfaces of the opercula.

Conclusions. Complete comprehension of the intricate vascularization patterns associated with the insula, as well as proficiency in insular anatomy, are prerequisites to accomplishing appropriate surgical planning and, ultimately, to completing successful exploration and removal of pathological lesions in this region.
Central nervous system leiomyosarcoma in patients with acquired immunodeficiency syndrome
Authors: Ritter Ann M. , Amaker Barbara H. , Graham R. Scott , Broaddus William C. , Ward John D.
Published: May 2009

✓ Leiomyosarcomas (LMSs) of the central nervous system are extremely rare; however, they are becoming more prevalent in immunocompromised patients. The authors present the cases of two patients with acquired immunodeficiency syndrome: one with LMS of the thoracic vertebral body and the other with LMS originating from the region of the cavernous sinus. The epidemiological and histological characteristics of LMS and its association with latent Epstein—Barr virus are discussed, as well as the treatments for this neoplasm.
Bilateral median nerve compression at the level of Struthers' ligament
Authors: Aydinlioglu Atif , Cirak Bayram , Akpinar Fuat , Tosun Nihat , Dogan Ali
Published: May 2009

✓ Struthers' ligament syndrome is a rare cause of median nerve entrapment. Bilateral compression of the median nerve is even more rare. It presents with pain, sensory disturbance, and/or motor function loss at the median nerve's dermatomal area. The authors present the case of a 21-year-old woman with bilateral median nerve compression caused by Struthers' ligament. She underwent surgical decompression of the nerve on both sides. To the authors' knowledge, this case is the first reported bilateral compression of the median nerve caused by Struthers' ligament. The presentation and symptomatology of Struthers' ligament syndrome must be differentiated from median nerve compression arising from other causes.
A giant intracranial mucocele associated with an orbitoethmoidal osteoma
Authors: Nakajima Yoshikazu , Yoshimine Toshiki , Ogawa Makoto , Takanashi Mayako , Nakamuta Kana , Maruno Motohiko , Hasegawa Hiroshi , Yokota Junichiro
Published: May 2009

✓ The authors present a rare case of a giant intracranial mucocele associated with an orbitoethmoidal osteoma in a patient suffering from a generalized convulsive disorder. The broad pedicle of the osteoma had penetrated the cribriform plate and extended intracranially to form a nodular mass in the olfactory groove. The intracranial portion of the osteoma was surrounded by a mucocele. Both the cyst wall and multilayered intracystic septations of the mucocele were indented by layers of the osteoma. Although the extracranial portion adhered to the mucosa of the ethmoidal sinus, there were no signs of sinus obstruction. No direct communication other than the osteoma was identified between the mucocele and the ethmoidal mucosa. The large cerebral defect, which the mucocele occupied, communicated directly with the lateral ventricle without any intervening membranous structures. A frontal craniotomy is recommended for exposure of the lesion and plastic repair of the dural defect.
Microvascular decompression for trigeminal neuralgia in Charcot-Marie-Tooth disease
Authors: de Matas Marcus , Francis Peter , Miles John B.
Published: May 2009

✓ The authors report on three patients suffering from coexistent trigeminal neuralgia (TGN) and Charcot-Marie-Tooth disease who, based on preoperative magnetic resonance tomographic angiography findings, underwent microvascular decompression. All patients had demonstrable neural compression and all experienced immediate postoperative pain relief. Symptoms recurred in one patient and required a second procedure in the form of a neurotomy. Two patients suffered from bilateral TGN.

When a patient with TGN suffers coexistent neurological disease and experiences bilateral symptoms, preoperative imaging and subsequent decompressive surgery may avoid the unacceptable risk of morbidity associated with bilateral ablative procedures.
Stent-assisted angioplasty of intracranial vertebrobasilar atherosclerosis: an initial experience
Authors: Rasmussen Peter A. , Perl John , Barr John D. , Markarian Georges Z. , Katzan Irene , Sila Cathy , Krieger Derk , Furlan Anthony J. , Masaryk Thomas J.
Published: May 2009

Object. Patients with intracranial vertebrobasilar artery (VBA) atherosclerotic occlusive disease have few therapeutic options. Unfortunately, VBA transient ischemic attacks (TIAs) herald a lethal or devastating event within 5 years in 25 to 30% of patients. The authors report their initial experience with eight patients in whom medically refractory TIAs secondary to intracranial posterior circulation atherosclerotic occlusive lesions were treated with stent-assisted angioplasty.

Methods. Eight patients (six men), ranging in age from 43 to 77 years, experienced signs and symptoms of VBA insufficiency despite combination therapy with warfarin and antiplatelet agents. Angiographic studies revealed severe distal vertebral (four patients), proximal basilar (one patient), or proximal and midbasilar stenoses (three patients). Aspirin and clopidogrel were administered for 3 days before primary angioplasty and stent placement, and this regimen was maintained by the patients on discharge. Patients underwent heparinization during the procedure and were given a bolus and 12-hour infusion of abciximab. A neurologist specializing in stroke evaluated all patients before and after the procedure.

The VBAs in all patients were successfully revascularized with 7 to 28% residual stenosis. Six patients experienced no neurological complications. One patient died the evening of the procedure due to a massive subarachnoid hemorrhage. Two patients had groin hematomas, one developed congestive heart failure, and one had transient encephalopathy. All surviving patients are asymptomatic up to 8 months postoperatively.

Conclusions. Although primary intracranial VBA angioplasty with stent insertion is technically feasible, complications associated with the procedure can be life threatening. As experience is gained with this procedure, it may be offered routinely as an alternative therapy to patients with medically refractory posterior circulation occlusive disease that may develop into catastrophic VBA insufficiency.
Relationships between the epileptic focus and hand area in central epilepsy: combining dipole models and anatomical landmarks
Authors: Gross Donald W. , Merlet Isabelle , Boling Warren , Gotman Jean
Published: May 2009

Object. When considering resection of epileptic generators near the central sulcus, it is essential to define the spatial relationship between the epileptic generator and the primary sensorimotor hand area. In this study, the authors assessed the accuracy of dipole modeling of electroencephalographic spikes and median nerve somatosensory evoked potentials (SSEPs) in defining this relationship preoperatively and noninvasively.

Methods. Epileptic spikes and SSEPs in patients with focal central area epilepsy were represented by dipole models coregistered onto global magnetic resonance images. In patients who underwent surgery, spike dipoles were also compared with findings of electrocorticography (ECoG) and with the resection area. To improve the accuracy of the dipole models, anatomical landmarks of the hand area were used to assess the error in SSEP dipole location, and this error measure was used to correct the location of spike dipoles.

Five patients with central epilepsy were studied, three of whom underwent ECoG-guided surgical resections. The location of SSEP dipoles correlated well with anatomical landmarks of the primary sensory hand area. The relative position of the spike and SSEP dipoles correlated well with the patients' ictal symptoms, ECoG findings, and the location of the epileptic focus (as defined by the resection cavity in patients who became seizure free postoperatively). Corrected spike dipoles were located even closer to the resection cavity.

Conclusions. The calculation of the relative location of spike and SSEP dipoles is a simple noninvasive method of determining the relationship between the primary hand area and an epileptic focus in the central area. The spatial resolution of this technique can be further improved using easily identifiable anatomical landmarks.
Telovelar approach to the fourth ventricle: microsurgical anatomy
Authors: Mussi Antonio C. M. , Rhoton Albert L.
Published: May 2009

Object. In the past, access to the fourth ventricle was obtained by splitting the vermis or removing part of the cerebellum. The purpose of this study was to examine the access to the fourth ventricle achieved by opening the tela choroidea and inferior medullary velum, the two thin sheets of tissue that form the lower half of the roof of the fourth ventricle, without incising or removing part of the cerebellum.

Methods. Fifty formalin-fixed specimens, in which the arteries were perfused with red silicone and the veins with blue silicone, provided the material for this study. The dissections were performed in a stepwise manner to simulate the exposure that can be obtained by retracting the cerebellar tonsils and opening the tela choroidea and inferior medullary velum.

Conclusions. Gently displacing the tonsils laterally exposes both the tela choroidea and the inferior medullary velum. Opening the tela provides access to the floor and body of the ventricle from the aqueduct to the obex. The additional opening of the velum provides access to the superior half of the roof of the ventricle, the fastigium, and the superolateral recess. Elevating the tonsillar surface away from the posterolateral medulla exposes the tela, which covers the lateral recess, and opening this tela exposes the structure forming the walls of the lateral recess.
Usefulness of postischemic thrombolysis with or without neuroprotection in a focal embolic model of cerebral ischemia
Authors: Yang Yi , Li Qui , Miyashita Hero , Howlett Wendy , Siddiqui Muzaffar , Shuaib Ashfaq
Published: May 2009

Object. Recent studies have shown that the use of thrombolysis in the setting of acute stroke is associated with an increased risk of cerebral hemorrhage. The time of onset of symptoms to initiation of medication and the dose levels of the thrombolytic agents are important determinants for the risk of cerebral hemorrhage. The authors evaluated the time course of thrombolysis-related hemorrhages in experimental settings and tested whether the addition of neuroprotective medication augments the efficacy of thrombolysis and reduces the incidence of hemorrhages.

Methods. Male Wistar rats were subjected to right middle cerebral artery embolization with an autologous thrombus and were then randomly assigned to one of the following groups: Group 1, saline-treated (2 hours after ischemic insult) animals as controls; Groups 2 to 4, high-dose urokinase (5000 U/kg) at 2, 3, and 6 hours after the insult; Group 5, low-dose urokinase (2500 U/kg) at 2 hours after the insult; Group 6, 20 mg/kg topiramate (TPM) at 2 hours after the insult; Group 7, a combination of 20 mg/kg TPM at 2 hours and low-dose urokinase (2500 U/kg) at 6 hours after the insult; and Group 8, 20 mg/kg TPM (20 mg/kg) at 2 hours and high-dose urokinase (5000 U/kg) at 2 hours after the insult. Neurological behavior and the infarct volume in the brain were assessed following cerebral embolism and the various treatments.

All animals in the single therapy and low-dose combination groups survived surgery. Three of eight animals treated with high-dose urokinase alone at 6 hours and three of six animals in the combined high-dose urokinase and TPM group developed fatal intracerebral hemorrhages. There was a significantly better neurological outcome at 24 hours in the animals treated with either medication compared with controls. The volume of the infarct in the saline-treated group was 54.2 ± 9%. The use of TPM at 2 hours led to a decrease in the infarct to 20.1 ± 11.2% (p < 0.01). Treatment with urokinase at 6 hours after the occlusion showed a trend toward protection; the infarct volume was 31.9 ± 14.1% (p < 0.05). The addition of TPM to low- or high-dose urokinase achieved better neuroprotection (8.2 ± 6% and 11.9 ± 10.7%, respectively; both p < 0.01).

Conclusions. In this study the authors show that the volume of the infarct can be significantly decreased with 2 to 6-hour delayed intraarterial thrombolysis with urokinase and that the efficacy of thrombolysis may be enhanced by combining neuroprotective agents like TPM. It is also shown that low-dose combination therapy may decrease the likelihood of cerebral hemorrhage.
Significant reduction in brain swelling by administration of nonpeptide kinin B2 receptor antagonist LF 16—0687Ms after controlled cortical impact injury in rats
Authors: Stover John F. , Dohse Nils-Kristian , Unterberg Andreas W.
Published: May 2009

Object. Identification of new therapeutic agents aimed at attenuating posttraumatic brain edema formation remains an unresolved challenge. Among others, activation of bradykinin B2 receptors is known to mediate the formation of brain edema. The purpose of this study was to investigate the protective effect of the novel nonpeptide B2 receptor antagonist, LF 16-0687Ms, in brain-injured rats.

Methods. Focal contusion was produced by controlled cortical impact injury. Five minutes after trauma, the rats received a single dose of no, low- (3 mg/kg body weight), or high- (30 mg/kg) dose LF 16-0687Ms. After 24 hours, the amount of brain swelling and hemispheric water content were determined. Low and high doses of LF 16-0687Ms significantly reduced brain swelling by 25% and 27%, respectively (p < 0.03). Hemispheric water content tended to be increased in the nontraumatized hemisphere.

In a subsequent series of 10 rats, cisternal cerebrospinal fluid (CSF) samples were collected to determine whether changes in substances associated with edema formation could clarify why LF 16-0687Ms increases water content. For this, the volume regulator amino acid taurine, the excitatory transmitter glutamate, and the adenosine triphosphate degradation products hypoxanthine and xanthine were measured. In CSF, the levels of taurine, hypoxanthine, and xanthine were significantly decreased following a single administration of LF 16-0687Ms (p < 0.005); the level of glutamate, however, was double that found in control animals (p < 0.05).

Conclusions. Using the present study design, a single administration of LF 16-0687Ms successfully reduced posttraumatic brain swelling. The decreased levels of taurine, hypoxanthine, and xanthine may reflect reduced posttraumatic brain edema, whereas the increased level of glutamate could account for the elevated water content observed in the nontraumatized hemisphere.
Marinacci communication
Authors: Stančić Marin F. , Burgić Nijaz , Mićović Vladimir
Published: May 2009

✓ Marinacci or reverse Martin—Gruber communication is a rare anatomical variation. Until now, in all reported cases the branch was diagnosed using electrophysiological studies but not substantiated anatomically. The authors report a case of ulnar—median nerve communication in the distal forearm that was discovered during carpal tunnel release surgery and confirmed postoperatively on electromyographic studies.
Diagnosis of spontaneous intracranial hypotension by using magnetic resonance myelography
Authors: Matsumura Akira , Anno Izumi , Kimura Hiroshi , Ishikawa Eiichi , Nose Tadao
Published: May 2009

✓ The authors describe a case of spontaneous intracranial hypotension in which the leakage site was determined by using magnetic resonance (MR) myelography. This technique demonstrated the route of cerebrospinal fluid (CSF) leakage, whereas other methods failed to show direct evidence of leakage. Magnetic resonance myelography is a noninvasive method that is highly sensitive in detecting CSF leakage. This is the first report in which a site of CSF leakage was detected using MR myelography.
Subfascial and submuscular methods of temporal muscle dissection and their relationship to the frontalis branch of the facial nerve
Authors: Coscarella Ernesto , Vishteh A. Giancarlo , Spetzler Robert F. , Seoane Eduardo , Zabramski Joseph M.
Published: May 2009

✓ The microsurgical anatomy of the temporal and zygomatic branches of the facial nerve are presented along with related local vasculature (frontal and parietal branches of the superficial temporal artery [STA]) as encountered when using subfascial and submuscular temporal muscle dissection techniques for anterolateral craniotomies.

Twenty sides were studied in 10 cadaveric specimens that had been previously injected with latex. The rami of the temporal and zygomatic branches of the facial nerve and branches of the STA were dissected out through pterional and orbitozygomatic approaches by using a submuscular or subfascial temporal muscle dissection technique.

The three rami of the temporal branch of the facial nerve (the auricularis, frontalis, and orbicularis) were found to run within the galeal plane of the scalp. The zygomatic branch of the facial nerve was found to course deeper than the most caudal extension of the galea, known as the superficial musculoaponeurotic layer. The frontal branch of the STA served as an important landmark for the subfascial or submuscular dissections because excessive reflection of the scalp flap inferior to the level of this vessel would inadvertently injure the frontalis branch of the facial nerve.

Subfascial and submuscular dissections of the temporal muscle offer an alternative to the interfascial technique during anterolateral craniotomies. Scalp and temporal dissection performed with careful attention to anatomical landmarks (frontal branch of the STA and the suprafascial fat pad) provides a safe and expeditious alternative to the traditional interfascial technique.
In vivo intracranial pressure dynamics in patients with hydrocephalus treated by shunt placement
Authors: Frim David M. , Goumnerova Lilliana C.
Published: May 2009

Object. With the commercial availability of a variety of shunt systems, there is considerable controversy over the choice of the most appropriate shunt valve for each individual with hydrocephalus. Although the performance characteristics of all shunt systems are well documented in the laboratory setting, there is little description of the in vivo dynamics of intracranial pressure (ICP) after implantation of commonly used shunt systems in humans. The authors coupled telemonitoring devices to several different shunt systems to measure the performance characteristics of these valve systems with respect to intraventricular pressure (IVP) at increments of head elevation.

Methods. Twenty-five patients with different shunt systems and three control patients without shunts were studied for IVP at 0°, 15°, 30°, 45°, 60°, 75°, and 90° of head elevation, and the resultant curves were analyzed for the best-fit regression coefficient. For purposes of analysis the authors grouped shunt valve systems by design characteristics into three groups: differential-pressure valves (r = −0.321 ± 0.061; 11 patients), nonsiphoning systems (r = −0.158 ± 0.027; 10 patients), and flow-regulated valves (r = −0.16 ± 0.056; four patients); there were three control patients without shunts (r = −0.112 ± 0.037).

Conclusions. The authors found that differential-pressure valves always caused ICP to drop to 0 by 30° of head elevation, whereas all other valve systems caused a more gradual drop in ICP, more consistent with pressures observed in the control patients without shunts. Not surprisingly, the differential-pressure valve group was found to have a significant difference in mean regression coefficient when compared with those in whom nonsiphoning shunts (p < 0.023) or no shunts were placed (p < 0.049). These data provide a basis for evaluating shunt valve performance and for predicting valve appropriateness in patients in whom characteristics such as pressure and flow dynamics are weighed in the choice of a specific valve for implantation.
Intracerebral steal phenomenon associated with global hyperemia in moyamoya disease during revascularization surgery
Authors: Oshima Hideki , Katayama Yoichi , Hirayama Teruyasu
Published: May 2009

Object. The collateral vessels in moyamoya disease appear to retain their ability to constrict during hypocapnia but not to dilate during hypercapnia. It has been claimed that hypercapnia, as well as hypocapnia, decreases the blood flow in regions perfused by collateral vessels, presumably because of intracerebral steal. If this holds true, the decrease in blood flow may be proportional to the global hyperemia in the brain. To establish appropriate hemodynamic control during revascularization surgery, the authors monitored the jugular bulb oxygen saturation (SjO2) intraoperatively, a method that could sensitively detect global hyperemia.

Methods. A total of 17 patients, most of whom presented with transient ischemic attacks or fluctuating neurological deficits, underwent intraoperative monitoring of their SjO2 and end-tidal carbon dioxide (ETCO2) after a state of anesthesia had been induced with isoflurane (Group 1) or propofol (Group 2). In eight of these patients, the regional cerebral blood flow (rCBF) of the collateral vessel territory was also monitored by laser Doppler flowmetry during the period of cortical exposure, and a total of 113 data sets (averaged values during 2.5-minute intervals) was collected. There was fluctuation in the ETCO2 levels ranging from 36 to 44 mm Hg. The mean SjO2 level was clearly greater (p < 0.01) in Group 1 (71.8 ± 2.2%) than in Group 2 (63.3 ± 2.1%). An episodic fall in rCBF was observed in association with a transient increase in SjO2. Such an event was not uncommon in Group 1 and there was a greater risk of rCBF decreasing when SjO2 exceeded a cutoff level of 76% (p < 0.01). This level could sometimes be reached at a broad range of ETCO2 readings (37–44 mm Hg). In Group 2, similar events sometimes occurred when SjO2 increased beyond 70%. However, this level could be reached only with a higher ETCO2 (42–44 mm Hg). The rCBF level was negatively correlated to SjO2 (p < 0.01), but not always to ETCO2, indicating that the episodic fall in rCBF was closely related to global hyperemia rather than the absolute level of hypercapnia.

Conclusions. The observed association between a fall in rCBF and global hyperemia supports the intracerebral steal hypothesis and indicates that it is prudent to avoid excessive global hyperemia. The optimal range of CO2 for isoflurane is more restricted than that for propofol, presumably because isoflurane induces hyperemia by itself. Monitoring of SjO2 appears to represent the most practical technique for detecting global hyperemia as well as global ischemia, both of which may cause ischemic complications in moyamoya disease.
Repeated radiosurgery for incompletely obliterated arteriovenous malformations
Authors: Maesawa Satoshi , Flickinger John C. , Kondziolka Douglas , Lunsford L. Dade
Published: May 2009

Object. The goal of this study was to define treatment results of repeated arteriovenous malformation (AVM) radiosurgery, namely AVM obliteration and complications.

Methods. The authors analyzed their experience with repeated AVM radiosurgery performed in 41 patients for whom follow-up review lasted at least 2 years. The median duration of follow up was 34 months (range 7–65 months) after repeated radiosurgery in this group. The residual nidus was located within the area of focus (in field) of the initial radiosurgery in 28 patients (68%). Initial doses to the margin varied from 12.5 to 20 Gy (median 18 Gy). During repeated treatment the dose to the margin varied from 12.5 to 20 Gy (median 17 Gy) and the retreated volumes ranged from 0.4 to 7 cm3 (median 2.1 cm3).

Follow-up angiography performed at least 2 years postradiosurgery revealed complete AVM obliteration in 21 (70%) of 30 patients. The estimated overall 2-year obliteration rate, based on findings on magnetic resonance imaging (eight of 11 obliterated) and angiography (29 of 41 obliterated) was 71%. Obliteration rates correlated with margin doses (p = 0.0045) with a trend toward higher rates in cases with in-field nidus persistence (p = 0.0637). The dose—response curve for AVM nidus obliteration was not significantly different from that of the initial radiosurgery. In two patients (5%) intracranial AVM hemorrhage developed within 125.9 risk years after repeated radiosurgery (1.6% per patient year). Persistent symptomatic adverse radiation effects developed in two (5%) of 41 patients following repeated radiosurgery. Postradiosurgical imaging changes were identified in 11 (27%) of 41 patients, which correlated with a 12-Gy volume from repeated surgery (p = 0.019).

Conclusions. When necessary, repeated AVM radiosurgery achieves obliteration with an acceptable risk. Despite the effects of previous irradiation, repeated radiosurgery required similar or slightly higher radiation doses to achieve the same in-field obliteration rates as those needed to obliterate an AVM that had not been treated by radiation previously.