bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimizing accuracy in magnetic resonance imaging—guided stereotaxis: a technique with validation based on the anterior commissure—posterior commissure line
Authors: diPierro Charles G. , Francel Paul C. , Jackson Theodore R. , Kamiryo Toshifumi , Laws Edward R.
Published: May 2009

Object. Some of the earliest successful frame-based stereotactic interventions directed toward the thalamus and basal ganglia depended on identifying the anterior commissure (AC) and posterior commissure (PC) in a sagittal ventriculogram and defining the intercommissural line that connects them in the midsagittal plane. The AC—PC line became the essential landmark for the localization of neuroanatomical targets in the basal ganglia and diencephalon and for relating them to stereotactic atlases.

Stereotactic/functional neurosurgery has come to rely increasingly on magnetic resonance (MR) imaging guidance, and methods for accurately determining the AC—PC line on MR imaging are being developed. The goal of the present article is to present the authors' technique.

Methods. The technique described uses MR sequences that minimize geometric distortion and registration error, thereby maximizing accuracy in AC—PC line determinations from axially displayed MR data. The technique is based on the authors' experience with the Leksell G-frame but can be generalized to other MR imaging—based stereotactic systems.

This methodology has been used in a series of 62 stereotactic procedures in 47 adults (55 pallidotomies and seven thalamotomies) with preliminary results that compare favorably with results reported when using microelectrode recordings. The measurements of the AC—PC line reported here also compare favorably with those based on ventriculography and computerized tomography scanning.

Conclusions. The methodology reported here is critical in maintaining the accuracy and utility of MR imaging as its role in modern stereotaxy expands. Accurate parameters such as these aid in ensuring the safety, efficacy, and reproducibility of MR-guided stereotactic procedures.
Presence of vitronectin and activated complement factor C9 on ventriculoperitoneal shunts and temporary ventricular drainage catheters
Authors: Lundberg Fredrik , Li Dai-Qing , Falkenback Dan , Lea Tor , Siesjö Peter , Söderström Sven , Kudryk Bohdan J. , Tegenfeldt Jonas O. , Nomura Sadahiro , Ljungh Åsa
Published: May 2009

Object. The pathogenesis of cerebrospinal fluid (CSF) shunt infection is characterized by staphylococcal adhesion to the polymeric surface of the shunt catheter. Proteins from the CSF—fibronectin, vitronectin, and fibrinogen—are adsorbed to the surface of the catheter immediately after insertion. These proteins can interfere with the biological systems of the host and mediate staphylococcal adhesion to the surface of the catheter. In the present study, the presence of fibronectin, vitronectin, and fibrinogen on CSF shunts and temporary ventricular drainage catheters is shown. The presence of fragments of fibrinogen is also examined.

Methods. The authors used the following methods: binding radiolabeled antibodies to the catheter surface, immunoblotting of catheter eluates, and scanning force microscopy of immunogold bound to the catheter surface. The immunoblot showed that vitronectin was adsorbed in its native form and that fibronectin was degraded into small fragments. Furthermore, the study demonstrated that the level of vitronectin in CSF increased in patients with an impaired CSF—blood barrier. To study complement activation, an antibody that recognizes the neoepitope of activated complement factor C9 was used. The presence of activated complement factor C9 was shown on both temporary catheters and shunts.

Conclusions. Activation of complement close to the surface of an inserted catheter could contribute to the pathogenesis of CSF shunt infection.
Growth of precultured human glioma biopsy specimens in nude rat brain
Authors: Engebraaten Olav , Hjortland Geir Olav , Hirschberg Henry , Fodstad Øystein
Published: May 2009

Object. The aim of this study was to develop an improved animal model for brain tumor study. The need for better and more relevant brain tumor models is generally acknowledged. Glioma tissue can be cultured directly from the biopsy specimen as tumor spheroids. Using such precultured tissue, a new in vivo model for studying human gliomas was established.

Methods. Precultured small tumor spheroids (< 300 µm) prepared from cell lines or tumor biopsy fragments were injected into the brains of immunodeficient rats by using a 5-µl Hamilton syringe that had a piston in the needle. Tumors could be established by injecting a single spheroid derived from the U-87MG cell line, whereas inoculation of 10 spheroids resulted in a tumor take comparable to that attained with injection of 106 single cells. Biopsy specimens obtained from six patients who underwent surgery for glioblastoma multiforme were cultured as organotypic spheroids for 11 to 18 days before inoculation into the rats. The animals were killed 3 months after spheroid implantation. Microscopic examination revealed tumor growth in 87.5 to 100% of the animals inoculated with tumor spheroids from all but one of the tumor biopsy specimens. Extensive invasion and cell migration along the nerve tracts of the corpus callosum was found in tumors that originated from four of the six biopsy specimens.

Conclusions. This approach, in which spheroids from precultured biopsy specimens are injected into the brains of immunodeficient animals, provides new means for experimental studies of human malignant brain tumors in a clinically relevant animal model.
Intracranial extension of an eccrine porocarcinoma
Authors: Ritter Ann M. , Graham R. Scott , Amaker Barbara , Broaddus William C. , Young Harold F.
Published: May 2009

✓ Eccrine porocarcinoma is a rare malignant tumor of the true sweat gland. It commonly presents in the lower extremities with lymphatic metastasis. The authors describe the clinical presentation, radiographic evidence, operative discoveries, and pathological findings in a patient with an eccrine porocarcinoma involving the soft tissue of the occiput, which had eroded through the cranium. A review of the literature failed to reveal any other such case. The discussion includes the epidemiology, pathogenesis, treatment, and outcome of eccrine porocarcinomas. The six reported cases of scalp eccrine tumors are reviewed.
Peripheral-type primitive neuroectodermal tumor arising in the tentorium
Authors: Katayama Yoichi , Kimura Shigeyoshi , Watanabe Takao , Yoshino Atsuo , Koshinaga Morimichi
Published: May 2009

✓ The authors report the case of a peripheral primitive neuroectodermal tumor (PNET) arising in the tentorium in a 5-year-old boy who presented with frequent vomiting and mild palsy of the left abducent nerve. Following complete surgical excision of the tumor via a transpetrosal approach, the patient has thus far been disease free for 7 years. The tumor tissue was composed of small cells with uniform round nuclei and minimal identifiable cytoplasm. Homer—Wright rosettes were frequently observed. Immunohistochemical studies demonstrated a positive reaction to HBA-71, which recognizes the cell surface glycoprotein p30/32, a product of the MIC2 gene. Both the clinical and immunohistochemical characteristics of this tumor are consistent with a diagnosis of peripheral PNET, which is genetically distinct from the more common intracranial PNET.
Destructive tophaceous calcium hydroxyapatite tumor of the infratemporal fossa
Authors: Grant Gerald A. , Wener Mark H. , Yaziji Hadi , Futran Neal , Bronner Mary P. , Mandel Neil , Mayberg Marc R.
Published: May 2009

✓ Tophaceous pseudogout is one of the rarest forms of crystal deposition disease, typically presenting as a destructive and invasive mass involving the temporomandibular joint or the infratemporal fossa region in the absence of any other articular manifestations. Previous cases have been assumed to be caused by calcium pyrophosphate dihydrate (CPPD) crystal deposition, based on finding weakly birefringent crystals in the involved tissues. The authors present the unique case of a 65-year-old woman with a destructive and invasive facial mass extending to the middle cranial fossa with microscopic and clinical features consistent with tophaceous pseudogout. High-resolution x-ray crystallographic powder diffraction and Fourier transformed infrared spectroscopy subsequently revealed that the crystals were composed of calcium hydroxyapatite without CPPD. The patient was later found to have primary hyperparathyroidism and mild hypercalcemia. This case demonstrates that tissue deposits of calcium hydroxyapatite can cause a destructive and invasive mass containing weakly birefringent crystals and raises the question of whether previous cases attributed to tophaceous pseudogout resulting from CPPD actually were composed of birefringent calcium hydroxyapatite.
Outcomes after stereotactically guided pallidotomy for advanced Parkinson's disease
Authors: Kondziolka Douglas , Bonaroti Eugene , Baser Susan , Brandt Fran , Kim Young Soo , Lunsford L. Dade
Published: May 2009

Object. Parkinson's disease (PD) is a prevalent neurodegenerative disorder that becomes refractory to medication as the disease progresses. Although in the past 5 years increasing numbers of patients have undergone stereotactically guided posteroventral pallidotomy for advanced PD, the safety and efficacy of surgery remains to be documented. The goal in this study was to determine the potential operative morbidity and types of functional outcomes by using validated PD rating scales and a patient survey.

Methods. In a prospective analysis of a consecutive surgical series the authors evaluated 58 patients with advanced PD who ranged in age from 40 to 79 years (mean 67 years) and who had undergone surgery between 1994 and 1997. They used a patient survey and the Unified Parkinson's Disease Rating Scale (UPDRS) to study patients during periods of medication administration (“on”) and withdrawal (“off”; mean off score before surgery = 96).

Temporary surgical morbidity was found in four patients (6.9%), three of whom developed transient dysarthria and one of whom exhibited transient confusion (1.7%). One patient had persistent dysarthria (1.7%). No patient developed a visual field deficit or sustained a brain hemorrhage. All patients were discharged from the hospital within 24 hours. Significant postsurgical improvements were noted in the UPDRS off-period total and motor scores, as well as in tremor, rigidity, bradykinesia, and contralateral dyskinesia (p < 0.005). Improvements persisted in dyskinesia and tremor for the 21 patients who were evaluated past 1 year. The authors found no improvement in any on-period symptoms except dyskinesia. Thirty-one (61%) of 51 patients surveyed reported functional gains and/or dramatic improvement in symptoms, 17 (33%) reported symptomatic improvement without functional gains, and three (6%) had minimal or no change in symptoms. No change in the mini mental state examination score was noted during follow up. There were no significant postoperative changes in the use of medication.

Conclusions. In advanced PD associated with either a medically refractory state with significant off periods or levodopa-induced dyskinesias, magnetic resonance imaging—guided pallidotomy with macrostimulation was associated with minimal morbidity and yet significantly reduced dyskinesia and off-period disability. These improvements were of value to the patient and persisted beyond the 1st year.
The efficacy of an abbreviated course of nimodipine in patients with good-grade aneurysmal subarachnoid hemorrhage
Authors: Toyota Brian D.
Published: May 2009

Object. Nimodipine therapy has become a standard component of the treatment regimen used in patients with aneurysmal subarachnoid hemorrhage (SAH). Its prescribed use at 60 mg every 4 hours for 21 days is based on reputable, randomized prospective studies. However, because only 20 to 30% of patients with SAH suffer clinical cerebral vasospasm, it is clear that most patients do not actually need the drug. Of course, this fact is not evident until several treatment days have passed. It is common practice, without well-documented consequences, to terminate nimodipine therapy before 21 days in certain clinical circumstances. The aim of this study was to evaluate the effectiveness of abbreviating the duration of nimodipine treatment in the setting of a good-grade aneurysmal SAH.

Methods. A retrospective clinical review was made of 90 consecutive patients who experienced a Hunt and Hess Grade I through III aneurysmal SAH and were treated with nimodipine for 15 days or less.

Conclusions. None of the patients studied suffered a delayed neurological deficit as a result of the abbreviated course of nimodipine.
Trigeminocardiac reflex during surgery in the cerebellopontine angle
Authors: Schaller Bernhard , Probst Rudolf , Strebel Stephan , Gratzl Otmar
Published: May 2009

Object. In different experimental studies authors have analyzed the autonomic responses elicited by the electrical, mechanical, or chemical stimulation of the trigeminal nerve system. The trigeminocardiac reflex (TCR) is a well-recognized phenomenon that consists of bradycardia, arterial hypotension, apnea, and gastric hypermotility. It occurs during ocular surgery and during other manipulations in and around the orbit. Thus far, it has not been shown that central stimulation of the trigeminal nerve can also cause this reflex.

Methods. The TCR was defined as clinical hypotension with a drop in mean arterial blood pressure (MABP) of more than 20% and bradycardia lower than 60 beats/minute. Pre-, intra-, and postoperative heart rate (HR) and MABP were reviewed retrospectively in 125 patients who underwent surgery for tumors of the cerebellopontine angle (CPA), and they were divided into two groups on the basis of the occurrence of the TCR during surgery. Of the 125 patients, 14 (11%) showed evidence of the TCR during dissection of the tumor near the trigeminal nerve at the brainstem. Their HRs fell 38% and their MABPs fell 48% during operative procedures as compared with preoperative levels. After cessation of manipulation, the HRs and the MABPs returned to preoperative levels. Risk factors for the occurrence of the TCR were compared with results from the literature.

Conclusions. The authors' results show the possibility of occurrence of a TCR during manipulation of the central part of the trigeminal nerve when performing surgery in the CPA.
Dutch Normal-Pressure Hydrocephalus Study: the role of cerebrovascular disease
Authors: Boon Agnita J. W. , Tans Joseph T. J. , Delwel Ernst J. , Egeler-Peerdeman Saskia M. , Hanlo Patrick W. , Wurzer Hans A. L. , Hermans Jo
Published: May 2009

Object. This study was conducted to determine the prevalence of cerebrovascular disease and its risk factors among patients with normal-pressure hydrocephalus (NPH) and to assess the influence of these factors on the outcome of shunt placement.

Methods. A cohort of 101 patients with NPH underwent shunt placement and was followed for 1 year. Gait disturbance and dementia were quantified using an NPH scale and handicap was determined using a modified Rankin scale (mRS). Primary outcome measures consisted of the differences between preoperative and last NPH scale and mRS scores. The presence of risk factors such as hypertension, diabetes mellitus, cardiac disease, peripheral vascular disease, male gender, and advancing age was recorded. Cerebrovascular disease was defined as a history of stroke or a computerized tomography (CT) scan revealing infarcts or moderate-to-severe white matter hypodense lesions.

The prevalence of risk factors for cerebrovascular disease was higher in the 45 patients with cerebrovascular disease than the 56 without it. Risk factors did not influence outcome after shunt placement. Intent-to-treat analysis revealed that the mean improvement in the various scales was significantly less for patients with a history of stroke (14 patients), CT scans revealing infarctions (13), or white matter hypodense lesions (32 patients) than for those without cerebrovascular disease. The proportion of patients who responded to shunt placement was also significantly lower among patients with than those without cerebrovascular disease (p = 0.02).

Conclusions. The authors identified a subgroup of patients with NPH and cerebrovascular disease who showed disappointing results after shunt placement. Cerebrovascular disease was an important predictor of poor outcome.
Sylvian aqueduct syndrome and global rostral midbrain dysfunction associated with shunt malfunction
Authors: Cinalli Giuseppe , Sainte-Rose Christian , Simon Isabelle , Lot Guillaume , Sgouros Spiros
Published: May 2009

Object. This study is a retrospective analysis of clinical data obtained in 28 patients affected by obstructive hydrocephalus who presented with signs of midbrain dysfunction during episodes of shunt malfunction.

Methods. All patients presented with an upward gaze palsy, sometimes associated with other signs of oculomotor dysfunction. In seven cases the ocular signs remained isolated and resolved rapidly after shunt revision. In 21 cases the ocular signs were variably associated with other clinical manifestations such as pyramidal and extrapyramidal deficits, memory disturbances, mutism, or alterations in consciousness. Resolution of these symptoms after shunt revision was usually slow. In four cases a transient paradoxical aggravation was observed at the time of shunt revision. In 11 cases ventriculocisternostomy allowed resolution of the symptoms and withdrawal of the shunt.

Simultaneous supratentorial and infratentorial intracranial pressure recordings performed in seven of the patients showed a pressure gradient between the supratentorial and infratentorial compartments, with a higher supratentorial pressure before shunt revision. Inversion of this pressure gradient was observed after shunt revision and resolution of the gradient was observed in one case after third ventriculostomy. In six recent cases, a focal midbrain hyperintensity was evidenced on T2-weighted magnetic resonance imaging sequences at the time of shunt malfunction. This rapidly resolved after the patient underwent third ventriculostomy.

Conclusions. It is probable that in obstructive hydrocephalus, at the time of shunt malfunction, the development of a transtentorial pressure gradient could initially induce a functional impairment of the upper midbrain, inducing upward gaze palsy. The persistence of the gradient could lead to a global dysfunction of the upper midbrain. Third ventriculostomy contributes to equalization of cerebrospinal fluid pressure across the tentorium by restoring free communication between the infratentorial and supratentorial compartments, resulting in resolution of the patient's clinical symptoms.
Surgical treatment of craniopharyngiomas: experience with 168 patients
Authors: Fahlbusch Rudolf , Honegger Jürgen , Paulus Werner , Huk Walter , Buchfelder Michael
Published: May 2009

Object. The goal of this study was to assess the outcome of surgical management in 168 consecutive patients harboring craniopharyngiomas treated between January 1983 and April 1997.

Methods. In 148 patients undergoing initial (primary) surgery, the pterional approach was most frequently used (39.2%), followed by the transsphenoidal approach (23.6%). For large retrochiasmatic craniopharyngiomas, the bifrontal interhemispheric approach was used increasingly over the pterional approach and led to improved surgical results. Total tumor removal was accomplished in 45.7% of transcranial and 85.7% of transsphenoidal procedures. The main reasons for incomplete removal were attachment to and/or infiltration of the hypothalamus, major calcifications, and attachment to vascular structures. The success rate in total tumor removal was inferior in the cases of tumor recurrence. The operative mortality rate in transcranial surgery was 1.1% in primary cases and 10.5% in cases of tumor recurrence. No patient died in the group that underwent transsphenoidal surgery. The rate of recurrence-free survival after total removal was 86.9% at 5 years and 81.3% at 10 years. In contrast, the 5-year recurrence-free survival rate was only 48.8% after subtotal removal and 41.5% after partial removal. Following primary surgery, the actuarial survival rate was 92.7% at 10 years, with the best results after complete tumor removal. At last follow up, 117 (79%) of 148 patients who underwent primary surgery were independent and without impairment.

Conclusions. Total tumor removal while avoiding hazardous intraoperative manipulation provides favorable early results and a high rate of long-term control in craniopharyngiomas.
Variables affecting convection-enhanced delivery to the striatum: a systematic examination of rate of infusion, cannula size, infusate concentration, and tissue—cannula sealing time
Authors: Chen Michael Y. , Lonser Russell R. , Morrison Paul F. , Governale Lance S. , Oldfield Edward H.
Published: May 2009

Object. Although recent studies have shown that convection can be used to distribute macromolecules within the central nervous system (CNS) in a homogeneous, targeted fashion over clinically significant volumes and that the volume of infusion and target location (gray as opposed to white matter) influence distribution, little is known about other factors that may influence optimum use of convection-enhanced distribution. To understand the variables that affect convective delivery more fully, we examined the rate of infusion, delivery cannula size, concentration of infusate, and preinfusion sealing time.

Methods. The authors used convection to deliver 4 µl of 14C-albumin to the striatum of 40 rats. The effect of the rate of infusion (0.1, 0.5, 1, and 5 µl/minute), cannula size (32, 28, and 22 gauge), concentration of infusate (100%, 50%, and 25%), and preinfusion sealing time (0 and 70 minutes) on convective delivery was examined using quantitative autoradiography, National Institutes of Health image analysis software, scintillation analysis, and histological analysis.

Higher rates of infusion (1 and 5 µl/minute) caused significantly (p < 0.05) more leakback of infusate (22.7 ± 11.7% and 30.3 ± 7.8% [mean ± standard deviation], respectively) compared with lower rates (0.1 µl/minute [4 ± 3.6%] and 0.5 µl/minute [5.2 µ 3.6%]). Recovery of infusate was significantly (p < 0.05) higher at the infusion rate of 0.1 µl/minute (95.1 ± 2.8%) compared with higher rates (85.2 ± 4%). The use of large cannulae (28 and 22 gauge) produced significantly (p < 0.05) more leakback (35.7 ± 8.1% and 21.1 ± 7.5%, respectively) than the smaller cannula (32 gauge [5.2 ± 3.6%]). Varying the concentration of the infusate and the preinfusion sealing time did not alter the volume of distribution, regional distribution, or infusate recovery.

Conclusions. Rate of infusion and cannula size can significantly affect convective distribution of molecules, whereas preinfusion sealing time and variations in infusate concentration have no effect in this small animal model. Understanding the parameters that influence convective delivery within the CNS can be used to enhance delivery of potentially therapeutic agents in an experimental setting and to indicate the variables that will need to be considered for optimum use of this approach for drug delivery in the clinical setting.
Malignant intravascular lymphomatosis associated with venous stenosis
Authors: Amagasaki Kenichi , Yamazaki Hiromichi , Ohmori Kimie , Koizumi Hidehito , Hashizume Kazuhiro , Sasaguchi Nobuo
Published: May 2009

✓ This 55-year-old man presented with malignant intravascular lymphomatosis, a rare vascular disorder of the central nervous system characterized by proliferation of malignant lymphoma cells. The clinical manifestations were focal neurological signs and progressive dementia. Angiography demonstrated stenoses of the cortical veins. Postmortem examination revealed infiltration of tumor cells into the lumen and vascular wall, although the stenoses were caused primarily by fibrin thrombi. To the authors' knowledge this is the first case of malignant intravascular lymphomatosis associated with venous stenosis.
Hemangiopericytoma of the third ventricle
Authors: Abrahams John M. , Forman Mark S. , Lavi Ehud , Goldberg Herbert , Flamm Eugene S.
Published: May 2009

✓ The authors present the first reported case of a hemangiopericytoma (HPC) occurring in the third ventricle. Most of these lesions are based in the meninges. There is only one other reported case of an intraventricular HPC; in that case the lesion was found in the lateral ventricle.

A 40-year-old right-handed man presented with a 3-month history of headaches. Clinical evaluation, including computerized tomography and magnetic resonance imaging studies, revealed a 1-cm enhancing lesion in the third ventricle. Given the findings on the preoperative imaging studies, the lesion was not consistent with some of the more commonly occurring tumors of the third ventricle, namely colloid cysts. A transcortical approach and resection of the lesion was performed without complication. The final pathological findings were consistent with those of an HPC.

Hemangiopericytomas rarely occur in the ventricles and may pose a difficult diagnostic dilemma based on their radiographic and gross appearances, as shown in this case. Because of this difficulty, histological confirmation is required to make a definitive diagnosis. These lesions have a propensity to recur and metastasize in the central nervous system and periphery, thus making the goal of treatment a complete surgical resection followed by postoperative radiation therapy in most cases.
Localization of somatosensory function by using positron emission tomography scanning: a comparison with intraoperative cortical stimulation
Authors: Bittar Richard G. , Olivier André , Sadikot Abbas F. , Andermann Frederick , Comeau Roch M. , Cyr Martin , Peters Terrence M. , Reutens David C.
Published: May 2009

Object. To investigate the utility of [15O]H2O positron emission tomography (PET) activation studies in the presurgical mapping of primary somatosensory cortex, the authors compared the magnitude and location of activation foci obtained using PET scanning with the results of intraoperative cortical stimulation (ICS).

Methods. The authors used PET scanning and vibrotactile stimulation (of the face, hand, or foot) to localize the primary somatosensory cortex before surgical resection of mass lesions or epileptogenic foci affecting the central area in 20 patients. With the aid of image-guided surgical systems, the locations of significant activation foci on PET scanning were compared with those of positive ICS performed at craniotomy after the patient had received a local anesthetic agent. In addition, the relationship between the magnitude and statistical significance of blood flow changes and the presence of positive ICS was examined.

In 22 (95.6%) of 23 statistically significant (p < 0.05) PET activation foci, spatially concordant sites on ICS were also observed. Intraoperative cortical stimulation was positive in 40% of the PET activation studies that did not result in statistically significant activation. In the patients showing these results, there was a clearly identifiable t-statistic peak that was spatially concordant with the site of positive ICS in the sensorimotor area. All PET activation foci with a t statistic greater than 4.75 were associated with spatially concordant sites of positive ICS. All PET activation foci with a t statistic less than 3.2 were associated with negative ICS.

Conclusions. Positron emission tomography is an accurate method for mapping the primary somatosensory cortex before surgery. The need for ICS, which requires local anesthesia, may be eliminated when PET foci with high (> 4.75) or low (< 3.20) t-statistic peaks are elicited by vibrotactile stimulation.
The parasellar region of human infants: cavernous sinus topography and surgical approaches
Authors: Weninger Wolfgang J. , Müller Gerd B.
Published: May 2009

Object. In this study the authors analyze the peculiarities of the parasellar anatomy and the topography of surgical approaches to the parasellar region (PSR) in human infants.

Methods. Forty-nine specimens of the PSR obtained at autopsy were studied using microdissection and histological analysis. Important distances between anatomical landmarks were measured with the aid of a dissecting microscope. One serially sectioned specimen was three-dimensionally reconstructed and analyzed on the computer screen by using the authors' new episcopic reconstruction technique.

Conclusions. The anatomy of the infant PSR differs distinctly from that of the adult. The parasellar portion of the internal carotid artery (ICA) does not form a siphon, but takes a straight course, and the venous pathways as well as the cranial and sympathetic nerves have different topographical relationships. Analyses of surgical approaches demonstrate that, in young children, the anterolateral approach can be used to reach the pterygopalatine compartment, the superior ophthalmic vein, and those pathological processes that extend from the orbit into the PSR. The approach via Parkinson's triangle can be used in 45% of cases to access the pathological processes that occur in the voluminous space above and behind the posterior flexure of the parasellar ICA. Taking this route, sympathetic nerve fibers passing through the PSR are not at risk, but some arterial branches that run within the lateral wall of the sinus can complicate this approach.

This study presents a guideline that can assist radiologists and neurosurgeons in the planning and performance of interventions within the PSR of neonates and young children.
Correlations between the apparent diffusion coefficient, water content, and ultrastructure after induction of vasogenic brain edema in cats
Authors: Kuroiwa Toshihiko , Nagaoka Tsukasa , Ueki Masato , Yamada Ichiro , Miyasaka Naoyuki , Akimoto Hideaki , Ichinose Shizuko , Okeda Riki , Hirakawa Kimiyoshi
Published: May 2009

Object. The authors examined the correlation between changes in the apparent diffusion coefficient, regional water content, and tissue ultrastructure after vasogenic brain edema.

Methods. Vasogenic edema was induced in the white matter of six cats by cortical cold lesioning. The trace of diffusion tensor (Trace[D]) obtained from magnetic resonance imaging to measure the orientationally averaged water diffusibility was compared with the corresponding tissue water content determined by gravimetric studies and with ultrastructural water localization. Edema fluid had spread to the subcortical and deep white matter by 4.5 hours postlesioning. The increase in Trace(D) showed a significant linear correlation with the increase in tissue water content, both in the subcortical and deep white matter as follows: y = 45.5x − 2367 (r = 0.94) and y = 37.0x − 1769 (r = 0.93), respectively, where x is the water content (gram water/gram tissue) and y the Trace(D) (× 10−6 mm2/second). On histological examination, nerve fibers were found to be dissociated in the white matter and the extracellular space was markedly enlarged with protein-rich fluid. No noticeable hydropic swelling of the cellular components was observed.

Conclusions. A linear correlation was observed between increases in Trace(D) and increases in extracellular water volume in in vivo vasogenic brain edema. A similar correlation between the subcortical and deep white matter showing different arrangements of nerve fibers (parallel compared with intermingled, respectively) indicated that measurement of Trace(D) is a suitable parameter for the evaluation of vasogenic brain edema.
Glutathione monoethyl ester and inhibition of the oxyhemoglobin-induced increase in cytosolic calcium in cultured smooth-muscle cells
Authors: Arai Takashi , Takeyama Naoshi , Tanaka Takaya
Published: May 2009

Object. The mechanism of arterial vasoconstriction caused by oxyhemoglobin production after subarachnoid hemorrhage was investigated.

Methods. Using a fluorescent Ca++ indicator (fura-2 acetoxymethyl ester), the change in the cytosolic intracellular Ca++ concentration, [Ca++]i, was measured in cultured rat vascular smooth-muscle cells exposed to oxyhemoglobin and other substances. Oxyhemoglobin induced transient elevation of smooth-muscle cell [Ca++]i in either the presence or absence of ethyleneglycol-bis (β-aminoethylether)-N,N′-tetraacetic acid, indicating that Ca++ released by oxyhemoglobin was derived from [Ca++]i stores. In contrast, methemoglobin had no effect on the smooth-muscle cells. Exposure of the cells to reactive oxygen species generated by xanthine plus xanthine oxidase yielded the same results as with oxyhemoglobin, that is, transient elevation of smooth-muscle cell [Ca++]i. Procaine (a Ca++ channel blocker) failed to inhibit the oxyhemoglobin-induced elevation of [Ca++]i. Ryanodine (a Ca++ channel opener) plus oxyhemoglobin caused markedly greater elevation of [Ca++]i than ryanodine alone, whereas thapsigargin (an adenosine triphosphate [ATP]-dependent Ca++ pump inhibitor) plus oxyhemoglobin had no additional effect when compared with thapsigargin alone. The oxyhemoglobin-induced elevation of [Ca++]i could be blocked by an Fe++ chelator (ferene), but not by an Fe+++ chelator (deferoxamine mesylate). Treatment with either dithiothreitol or glutathione monoethyl ester markedly inhibited the oxyhemoglobin-induced elevation of [Ca++]i.

Conclusions. These results indicate that Fe++-catalyzed hydroxyl radicals generated from oxyhemoglobin-derived free radicals induce the elevation of [Ca++]i by inhibiting the ATP-dependent Ca++ pump rather than the Ca++ channels in the sarcoplasmic reticulum and that thiols may prevent Ca++ pump inactivation by inhibiting the oxidation of membrane sulfhydryl groups.
Surgically created fourth—third cranial nerve communication: temporary success in a child with bilateral third nerve hamartomas
Authors: Frisén Lars , von Essen Claes , Roos Arne
Published: May 2009

✓ Shortly after birth, an otherwise healthy infant developed eye deviation and ptosis due to a hamartomatous lesion of the interpeduncular segment of the right oculomotor nerve. The left nerve became similarly involved when the child was 1.5 years of age. Direct nerve repair was not possible. Instead, the trochlear nerve was divided and its proximal end was attached to the distal end of the third nerve. Elevation of the upper eyelid and partial adduction of the eye developed gradually over the ensuing 3 to 5 months. Both functions were lost after an additional 2 months, presumably as a result of tumor recurrence or neuroma formation. This case report shows that surgically created fourth—third cranial nerve communication is feasible and may merit consideration under similar circumstances.
Middle ear adenocarcinoma with intracranial extension
Authors: Paulus Werner , Romstöck Johann , Weidenbecher Manfred , Huk WalterJ. , Fahlbusch Rudolf
Published: May 2009

✓ Middle ear adenocarcinoma is a very rare, locally invasive neoplasm assumed to arise from the middle ear mucosa. Although endolymphatic sac tumor (aggressive papillary middle ear tumor) and jugulotympanic paraganglioma may show brain invasion, intracranial extension of histologically confirmed middle ear adenocarcinoma has not been previously reported. The authors describe a 53-year-old man who suffered from otalgia and tinnitus for more than 10 years and from neurological deficits for 1 year due to a large temporal bone tumor that invaded the temporal lobe. A combined neurosurgical and otolaryngological resection was performed. Pathological analysis revealed a low-grade adenocarcinoma of a mixed epithelial—neuroendocrine phenotype, which showed a close histological similarity to, and topographical relationship with, middle ear epithelium. The authors conclude that middle ear adenocarcinoma belongs to the spectrum of extracranial tumors that have possible local extension to the brain.
Saphenous vein interposition graft for recurrent carotid stenosis after prior endarterectomy and stent placement
Authors: Coumans Jean-Valéry C. E. , Watson Vance E. , Picken Catherine A. , McGrail Kevin M.
Published: May 2009

✓ Although the use of carotid artery stents is increasing, the management of recurrent stenosis after their placement is undefined. The authors report on a patient who underwent two left carotid endarterectomies followed by left carotid angioplasty and stent placement for recurrent stenosis. A third symptomatic recurrence was subsequently managed by placement of a saphenous vein interposition graft from the common carotid artery to the distal cervical internal carotid artery. The patient remained without hemispheric or retinal ischemia at his 5-month follow-up visit. Interposition grafting should be considered as a treatment option for carotid restenosis after initial endarterectomy and stent placement.
Recurrent stenosis of common carotid—intracranial internal carotid interposition saphenous vein bypass graft caused by intimal hyperplasia and treated with endovascular stent placement
Authors: Brennan Jeffrey W. , Morgan Michael K. , Sorby William , Grinnell Verity
Published: May 2009

✓ Intimal hyperplasia is a well-known cause of delayed stenosis in vein bypass grafts in all types of vascular surgery. Options for treatment of stenosis in peripheral and coronary artery bypass grafts include revision surgery and the application of endovascular techniques such as balloon angioplasty and stent placement. The authors present a case of stenosis caused by intimal hyperplasia in a high-flow common carotid artery—intracranial internal carotid artery (IICA) saphenous vein interposition bypass graft that had been constructed to treat a traumatic pseudoaneurysm of the intracavernous ICA. The stenosis recurred after revision surgery and was successfully treated by endovascular stent placement in the vein graft. The literature on stent placement for vein graft stenoses is reviewed, and the authors add a report of its application to external carotid—internal carotid bypass grafts. Further study is required to define the role of endovascular techniques in the management of stenotic cerebrovascular disease.
Integration of preoperative and intraoperative functional brain mapping in a frameless stereotactic environment for lesions near eloquent cortex
Authors: McDonald Jeffrey D. , Chong Brian W. , Lewine Jeffrey D. , Jones Greg , Burr Robert B. , McDonald Paul R. , Koehler Spencer B. , Tsuruda Jay , Orrison William W. , Heilbrun M. Peter
Published: May 2009

✓ The authors present a method of incorporating preoperative noninvasive functional brain mapping data into the frameless stereotactic magnetic resonance (MR) imaging dataset used for image-guided resection of brain lesions located near eloquent cortex. They report the use of functional (f)MR imaging and magnetic source (MS) imaging for preoperative mapping of eloquent cortex in difficult cases of brain tumor resection such as those in which there are large expansive masses or in which reoperations are required and the anatomy is distorted from prior treatments. To correlate methods of preoperative and intraoperative mapping localization directly, the authors have developed techniques of importing preoperative MS and fMR imaging data into an image-guided frameless stereotactic computer workstation. The data appear as a seamless overlay on the same preoperative volumetric MR imaging dataset used for stereotactic guidance during the operation. Intraoperatively identified functional locations mapped by cortical stimulation are recorded as digitally registered points. This approach should prove useful in assessing the accuracy and reliability of various preoperative functional brain mapping techniques.
Report of 190 consecutive cases of large acoustic tumors (vestibular schwannoma) removed via the translabyrinthine approach
Authors: Lanman Todd H. , Brackmann Derald E. , Hitselberger William E. , Subin Bill
Published: May 2009

Object. The choice of approach for surgical removal of large acoustic neuromas is still controversial. The authors reviewed the results in a series of patients who underwent removal of large tumors via the translabyrinthine approach.

Methods. The authors conducted a database analysis of 190 patients (89 men and 101 women) with acoustic neuromas 3 cm or greater in size. The mean age of these patients was 46.1 ± 15.6 years. One hundred seventy-eight patients underwent primary translabyrinthine surgical removal and 12 underwent surgery for residual tumor. Total tumor removal was accomplished in 183 cases (96.3%). The tumor was adherent to the facial nerve to some degree in 64% of the cases, but the facial nerve was preserved anatomically in 178 (93.7%) of the patients. Divided nerves were repaired by primary attachment or cable graft. Facial nerve function was assessed immediately after surgery, at the time of discharge, and at 3 to 4 weeks and 1 year after discharge. Excellent function (House—Brackmann facial nerve Grade I or II) was present in 55%, 33.9%, 38.8%, and 52.6% of the patients for each time interval, respectively, with acceptable function (Grades I—IV) in 81% at 1 year. Cerebrospinal fluid leakage that required surgical repair occurred in only 1.1% of the patients and meningitis in 3.7%. There were no deaths.

Conclusions. Use of the translabyrinthine approach for removal of large tumors resulted in good anatomical and functional preservation of the facial nerve, with minimum incidence of morbidity and no incidence of mortality. The authors continue to recommend use of this approach for acoustic tumors larger than 3 cm and for smaller tumors when hearing preservation is not an issue.
Magnetic resonance cisternography used to determine precise topography of the facial nerve and three components of the eighth cranial nerve in the internal auditory canal and cerebellopontine cistern
Authors: Ryu Hiroshi , Tanaka Tokutaro , Yamamoto Seiji , Uemura Kenichi , Takehara Yasuo , Isoda Haruo
Published: May 2009

Object. The detailed anatomy of intracranial structures has been studied mainly in cadavers, but the absence of cerebrospinal fluid and blood pressure in these models distorts normal spatial relationships. The authors investigated the rotation of the facial nerve (FN), superior vestibular nerve (SVN), inferior vestibular nerve (IVN), and cochlear nerve (CN) in the internal auditory canal (IAC) and cerebellopontine cistern in human volunteers and compared their results with those reported in cadaver studies.

Methods. The IACs and cerebellopontine cisterns of 30 normal adults (34 sides) were examined using magnetic resonance (MR) cisternography with a heavily T2-weighted two-dimensional fast spin—echo technique. The positions of the four components were unaffected by the presence of the meatal loop of the anterior inferior cerebellar artery in the IAC. The spatial relationship between the FN and SVN was quite constant, but the spatial relationship between the CN and SVN was quite variable: the former changed position, mainly in the IAC, on nine (26.5%) of 34 sides, and in the cerebellopontine cistern on the other sides (73.5%), conflicting with findings in cadaver studies.

Conclusions. It is more accurate to describe the CN and IVN as coursing beneath the SVN in either the IAC or cerebellopontine cistern, rather than stating that the three components rotate, as reported in cadaver studies. The MR cisternography studies provided quite detailed information about the topography of the four components and the relationship between the blood vessels and cranial nerves in the IAC and the cerebellopontine cistern.
The acute period of recovery from traumatic brain injury: posttraumatic amnesia or posttraumatic confusional state?
Authors: Stuss Donald T. , Binns Malcolm A. , Carruth Fiona G. , Levine Brian , Brandys Clare E. , Moulton Richard J. , Snow William G. , Schwartz Michael L.
Published: May 2009

Object. The goal of this study was to characterize more fully the cognitive changes that occur during the period of acute recovery after traumatic brain injury (TBI).

Methods. The pattern of performance recovery on attention and memory tests was compared with the results of the Galveston Orientation and Amnesia Test (GOAT). Tests of memory and attention were administered serially to a hospitalized group of patients with TBI of varying severity. The tests differed in their level of complexity and/or requirement for more effortful or strategic processing. The authors found a regular pattern to recovery. As expected, ability to perform on simpler tests was recovered before performance on more effortful ones. The ability to recall three words freely after a 24-hour delay (the operational definition in this study of return to continuous memory) was recovered last, later than normal performance on the GOAT. Ability to perform simple attentional tasks was recovered before the less demanding memory task (recognition); ability to perform more complex attentional tasks was recovered before the free recall of three words after a 24-hour delay. This recovery of attention before memory was most notable and distinct in the group with mild TBI.

Conclusions. The period of recovery after TBI, which is currently termed posttraumatic amnesia, appears to be primarily a confusional state and should be labeled as such. The authors propose a new definition for this acute recovery period and argue that the term posttraumatic confusional state should be used, because it more appropriately and completely characterizes the early period of recovery after TBI.
Use of the radial forearm microvascular free-flap graft for cranial base reconstruction
Authors: Schwartz Marc S. , Cohen James I. , Meltzer Toby , Wheatley Michael J. , McMenomey Sean O. , Horgan Michael A. , Kellogg Jordi X. , Delashaw Johnny B.
Published: May 2009

Object. Reconstruction of the cranial base after resection of complex lesions requires creation of both a vascularized barrier to cerebrospinal fluid (CSF) leakage and tailored filling of operative defects. The authors describe the use of radial forearm microvascular free-flap grafts to reconstruct skull base lesions, to fill small tissue defects, and to provide an excellent barrier against CSF leakage.

Methods. Ten patients underwent 11 skull base procedures including placement of microvascular free-flap grafts harvested from the forearm and featuring the radial artery and its accompanying venae comitantes. Operations included six craniofacial, three lateral skull base, and two transoral procedures for various diseases. Excellent results were obtained, with no persistent CSF leaks, no flap failures, and no operative infections. One temporary CSF leak was easily repaired with flap repositioning, and at one flap donor site minor wound breakdown was observed. One patient underwent a second procedure for tumor recurrence and CSF leakage at a site distant from the original operation.

Conclusions. Microvascular free tissue transfer reconstruction of skull base defects by using the radial forearm flap provides a safe, reliable, low-morbidity method for reconstructing the skull base and is ideally suited to “low-volume” defects.