bluuebunny/crossref_metadata_2025 huggingface dataset:
Intrasellar chordomas mimicking pituitary adenoma
Authors: Thodou Eleni , Kontogeorgos George , Scheithauer Bernd W. , Lekka Ioanna , Tzanis Spyros , Mariatos Panagiotis , Laws Edward R.
Published: May 2009

Object. Whereas chordomas involving the sellar region are uncommon, largely or entirely intrasellar examples are rare. The goal in this study was to present examples of these rare tumors as a guide to their proper diagnosis and treatment.

Methods. The authors report three cases in which the chordomas filled the pituitary fossa and presented as nonfunctioning pituitary adenomas. All lesions exhibited the typical histological patterns and immunophenotype of chordoma. One tumor, studied ultrastructurally and subjected to DNA analysis, was shown to have a diploid histogram. The authors present a clinicopathological study of these three cases and review the literature on intrasellar chordomas.

Conclusions. Although these tumors are easily misdiagnosed and therefore may not receive optimal treatment, aggressive surgical resection can yield a favorable prognosis in lesions with a limited extent.
Clinical significance of pedicle aneurysms on feeding vessels, especially those located in infratentorial arteriovenous malformations
Authors: Westphal Manfred , Grzyska Ulrich
Published: May 2009

Object. The diminishing threshold for the application of neuroimaging leads to an increasingly frequent diagnosis of previously asymptomatic arteriovenous malformations (AVMs). In such a context, it is warranted to define the criteria that make a lesion potentially hazardous so that neurosurgeons and patients reach a decision concerning how to manage the AVM. In addition to the proposed grading system for AVMs, which assesses the risk of an actual treatment procedure, several studies have been concerned with the evaluation of angioarchitectural features. The goal of the present study is to demonstrate the significance of feeding vessel pedicle aneurysms, especially those found in infratentorial AVMs.

Methods. To determine the incidence of associated aneurysms, the authors reviewed an unselected cohort of 242 consecutive patients with AVMs managed between 1989 and 1999. Within this group were 240 patients who were treated by surgery, endovascular techniques, or a combination of both. Of these patients, 216 harbored a supratentorial and 24 an infratentorial AVM. Two additional patients with supratentorial AVMs underwent treatment of ruptured aneurysms without treatment of the AVMs. In six of the patients with supratentorial AVMs, proximal flow-related aneurysms were found on major feeding arteries, only one of which had caused hemorrhage. In only one patient were there additional distal feeding vessel pedicle aneurysms near the AVM, one of which had caused a major hemorrhage. In contrast, four of 24 patients with infratentorial AVMs had distal feeding artery pedicle aneurysms. Three of these aneurysms had caused hemorrhage.

Conclusions. Pedicle aneurysms on feeding vessels are frequently associated with hemorrhage (four of five cases in this series). In our cohort of 242 treated patients (240 treated for AVM and two for an aneurysm), feeding vessel pedicle aneurysms appear to occur more frequently in conjunction with infratentorial AVMs, which justifies aggressive management to prevent incidences of morbidity associated with rupture of the aneurysm.
Histopathological study of venous aneurysms in patients with dural arteriovenous fistulas
Authors: Hamada Jun-Ichiro , Yano Shigetoshi , Kai Yutaka , Koga Kazunari , Morioka Motohiro , Ishimaru Yasuji , Ushio Yukitaka
Published: May 2009

Object. Of all intracranial dural arteriovenous fistulas (DAVFs), those with cortical venous drainage associated with cortical venous ectasia or varices are predisposed to an aggressive course and produce progressive neurological symptoms or hemorrhages. The authors undertook a histological examination of venous aneurysms and arterialized veins in the proximity of these aneurysms that had been surgically removed in patients with DAVFs.

Methods. Surgical specimens were obtained in eight patients. The excised venous aneurysms and the arterialized veins in their proximity were stained using hematoxylin and eosin, van Gieson's elastic, and Masson's trichrome stain. Immunostaining was also performed for alpha smooth-muscle actin, desmin, and factor VIII antigen. Five of the patients had presented with venous hypertension, and three had intracranial hemorrhages. The arterialized vein obtained in the proximity of the venous aneurysm exhibited local irregular intimal thickening; the internal elastic lamina (IEL) was grossly preserved. All venous aneurysms in patients with venous hypertension manifested medial thickening and local intimal thickening with loss of IEL; the thickness of the wall was relatively uniform. In contrast, the wall thickness of venous aneurysms in patients with hemorrhage was extremely irregular and there was no clear delineation between the media and the intima. In media with complete disappearance of IEL, there was scant muscle tissue.

Conclusions. Degenerative changes in venous aneurysms in patients with hemorrhage were much greater than in patients with venous hypertension, possibly because hemorrhages result from a more complicated interplay of anatomical, hemodynamic, and degenerative factors.
Resection of suprasellar tumors by using a modified transsphenoidal approach
Authors: Kouri Joshua G. , Chen Michael Y. , Watson Joseph C. , Oldfield Edward H.
Published: May 2009

✓ Generally accepted contraindications to using a transsphenoidal approach for resection of tumors that arise in or extend into the suprasellar region include a normal-sized sella turcica, normal pituitary function, and adherence of tumor to vital intracranial structures. Thus, the transsphenoidal approach has traditionally been restricted to the removal of tumors involving the pituitary fossa and, occasionally, to suprasellar extensions of such tumors if the sella is enlarged. However, conventional transcranial approaches to the suprasellar region require significant brain retraction and offer limited visualization of contralateral tumor extension and the interface between the tumor and adjacent structures, such as the hypothalamus, third ventricle, optic apparatus, and major arteries. In this paper the authors describe successful removal of suprasellar tumors by using a modified transsphenoidal approach that circumvents some of the traditional contraindications to transsphenoidal surgery, while avoiding some of the disadvantages of transcranial surgery.

Four patients harbored tumors (two craniopharyngiomas and two hemangioblastomas) that arose in the suprasellar region and were located either entirely (three patients) or primarily (one patient) within the suprasellar space. All patients had a normal-sized sella turcica. Preoperatively, three of the four patients had significant endocrinological deficits signifying involvement of the hypothalamus, pituitary stalk, or pituitary gland. Two patients exhibited preoperative visual field defects. For tumor excision, a recently described modification of the traditional transsphenoidal approach was used. Using this modification, one removes the posterior portion of the planum sphenoidale, allowing access to the suprasellar region. Total resection of tumor was achieved (including absence of residual tumor on follow-up imaging) in three of the four patients. In the remaining patient, total removal was not possible because of adherence of tumor to the hypothalamus and midbrain. One postoperative cerebrospinal fluid leak occurred. Postoperative endocrinological function was worse than preoperative function in one patient. No other new postoperative endocrinological or neurological deficits were encountered.

This study demonstrates the feasibility of using a modified transsphenoidal approach for resection of certain suprasellar, nonpituitary tumors.
Origin of the Drake fenestrated aneurysm clip
Authors: Del Maestro Rolando F.
Published: May 2009

✓ The development of the Drake fenestrated aneurysm clip is a study in the history of ideas. This communication outlines the conception and solution of a surgical problem involved with the clipping of large basilar tip aneurysms. Dr. Charles G. Drake's ability to modify old ideas and experiment with new ones was instrumental to the conceptual idea of a fenestrated clip. Dr. Frank H. Mayfield and Mr. George Kees, Jr. played essential roles in bringing the idea to a reality. The development of the fenestrated clip has added substantially to the armamentarium of the aneurysm surgeon in dealing with large and complex aneurysms.
Long-term follow-up study of unruptured vertebral artery dissection: clinical outcomes and serial angiographic findings
Authors: Nakagawa Kazuhiko , Touho Hajime , Morisako Toshitaka , Osaka Yasuhiko , Tatsuzawa Kazunori , Nakae Haruhiko , Owada Kei , Matsuda Kazuya , Karasawa Jun
Published: May 2009

Object. Although the spontaneous occurrence of an unruptured vertebral artery (VA) dissection has increasingly been recognized as a relatively common cause of stroke, and the clinical aspects of this lesion have gradually been determined, its natural course remains obscure. The main goal of this study was to clarify the management protocol for this condition by examining serial angiographic changes in patients with unruptured VA dissections.

Methods. Seventeen patients with unruptured VA dissections, including 13 men and four women, were clinically and angiographically examined between 1993 and 1998. All patients were observed using serial angiography studies. The initial angiography examinations most frequently revealed stenotic lesions (appearance of a pearl-andstring sign or string sign) in eight (47.1%) of 17 cases. In 15 cases (88.2%), changes in the lesions were evident on follow-up angiography studies. Stenotic lesions resulted in occlusion in four cases, normalization in three, and subsequent formation of an aneurysm in one case, which was treated successfully by proximal occlusion of the affected vessel performed using a detachable balloon. Occluded lesions, which were initially observed in three patients, recanalized in two patients and remained unchanged in one patient. Fusiform dilation alone was demonstrated in three patients during the initial angiography session; these lesions became normalized or were unchanged on follow-up studies. Saccular aneurysms were observed in two patients. In one of these cases, proximal ligation of the parent artery was successfully performed because of subsequent aneurysm enlargement. A double lumen, which appeared in one patient with an extradural VA dissection, became occluded. Magnetic resonance T2-weighted imaging studies revealed infarction corresponding to the posterior circulation in seven cases. During long-term observation in this series, good or excellent recovery was obtained in 14 (87.5%) of 16 patients, and moderate or severe disability in two (12.5%); one patient was lost to follow up after the second angiography study.

Conclusions. A follow-up angiography study must be performed during the early stage (within approximately 3 weeks after onset of symptoms) to confirm the formation or enlargement of an aneurysm, because such conditions may be amenable to surgical treatment. Unruptured VA dissection could otherwise be treated and followed conservatively. Although the majority of dissected lesions seem likely to stabilize within a few months, as evidenced on angiography, in some cases a longer observation period is required.
Brachial plexus dorsal rhizotomy in the treatment of upper-limb spasticity
Authors: Bertelli Jayme Augusto , Ghizoni Marcos Flavio , Michels Adalberto
Published: May 2009

Object. This study was conducted to evaluate the effects of dorsal rhizotomy on upper-limb spasticity, functional improvement, coordination, and hand sensibility.

Methods. Fifteen spastic upper limbs in 13 patients were selected and prospectively studied. Brachial plexus dorsal rhizotomy was performed in which two, three, or four dorsal roots were completely sectioned. Patients were followed up for at least 12 months after surgery; the mean follow-up period was 15.6 months and the maximum period was 30 months. A remarkable relief of spasticity was observed in all cases. Recurrence was observed in only one patient and was caused by insufficient dorsal root section. Functional improvement was observed in all cases, and functional improvement in the hand was found to be related to the presence of active finger extension in the preoperative period. Even when extended dorsal root section was performed, no hand anesthesia, either total or partial, was observed. No patient lost movement ability in the postoperative period, and no ataxic limbs were observed.

Conclusions. Brachial plexus dorsal rhizotomy is very effective as a treatment for upper-limb spasticity and results in functional improvement without loss of sensation in the hand.
Venous ophthalmodynamometry: a noninvasive method for assessment of intracranial pressure
Authors: Firsching Raimund , Schütze Michael , Motschmann Markus , Behrens-Baumann Wolfgang
Published: May 2009

Object. The goal of this study was to examine the potential use of ophthalmodynamometry in the noninvasive assessment of intracranial pressure (ICP). Under normal conditions, pressure within the central retinal vein is equal to or greater than ICP, because the central retinal vein passes through the optic nerve before it drains into the cavernous sinus. The optic nerve sheath is the place where ICP affects retinal venous pressure. Suction ophthalmodynamometry is an established method of investigation in ophthalmology to determine the pressure of the central retinal artery. Although observations of papilledema and lack of venous pulsations are commonly used to provide a vague assessment of ICP, ophthalmodynamometry may be used to determine the pressure of the central retinal vein. This venous pressure has never been compared with ICP.

Methods. In this study the pressure of the central retinal vein was recorded in 22 patients who underwent continuous simultaneous registration of ICP for various reasons, mainly for suspected hydrocephalus. A comparison of the two pressures was made. The results indicated a highly significant linear correlation between central retinal vein pressure and ICP.

These results are of great practical value because up-to-date reliable ICP monitoring has only been possible by using invasive means, by placing a probe extradurally or subdurally into the brain parenchyma or a ventricle.

Conclusions. Ophthalmodynamometry can be relevant for momentary assessment and is not suitable for continuous monitoring. However, this technique can easily be repeated and may be used whenever increased ICP is suspected in a patient suffering from hydrocephalus, brain tumors, or head injury.
Clinical cerebral microdialysis: a methodological study
Authors: Hutchinson Peter J. , O'Connell Mark T. , Al-Rawi Pippa G. , Maskell Lynn B. , Kett-White Rupert , Gupta Arun K. , Richards Hugh K. , Hutchinson David B. , Kirkpatrick Peter J. , Pickard John D.
Published: May 2009

Object. Clinical microdialysis enables monitoring of the cerebral extracellular chemistry of neurosurgical patients. Introduction of the technique into different hospitals' neurosurgical units has resulted in variations in the method of application. There are several variables to be considered, including length of the catheter membrane, type of perfusion fluid, flow rate of perfusion fluid, and on-line compared with delayed analysis of samples. The objects of this study were as follows: 1) to determine the effects of varying catheter characteristics on substance concentration; 2) to determine the relative recovery and true extracellular concentration by varying the flow rate and extrapolating to zero flow; and 3) to compare substance concentration obtained using a bedside enzyme analyzer with that of off-line high-performance liquid chromatography (HPLC).

Methods. A specially designed bolt was used to conduct two adjacent microdialysis catheters into the frontal cortex of patients with head injury or poor-grade subarachnoid hemorrhage who were receiving ventilation. One reference catheter (10-mm membrane, perfused with Ringer's solution at 0.3 µl/minute) was constant for all studies. The other catheter was varied in terms of membrane length (10 mm or 30 mm), perfusion fluid (Ringer's solution or normal saline), and flow rate (0.1–1.5 µl/minute). The effect of freezing the samples on substance concentration was established by on-line analysis and then repeated analysis after storage at −70°C for 3 months. Samples assayed with the bedside enzyme analyzer were reassessed using HPLC for the determination of glutamate concentrations.

Conclusions. Two adjacent microdialysis catheters that were identical in membrane length, perfusion fluid, and flow rate showed equivalent results. Variations in perfusion fluid and freezing and thawing of samples did not result in differences in substance concentration. Catheter length had a significant impact on substance recovery. Variations in flow rate enabled the relative recovery to be calculated using a modification of the extrapolation-to-zero-flow method. The recovery was approximately 70% at 0.3 µl/minute and 30% at 1 µl/minute (10-mm membrane) for all analytes. Glutamate results obtained with the enzyme analyzer showed good correlation with those from HPLC.
Experimental study of medullary trigeminal evoked potentials: development of a new method of intraoperative monitoring of the medulla oblongata
Authors: Oikawa Tomoyoshi , Matsumoto Masato , Sasaki Tatsuya , Kodama Namio
Published: May 2009

Object. The goal of this study was to develop a new method of intraoperative monitoring of functions located in the lateral portion of the medulla oblongata. Based on the fact that the spinal trigeminal nucleus and tract are located in the lateral portion of the medulla oblongata, the authors intended to investigate the efficacy of trigeminal evoked potentials (TEPs) in intraoperative monitoring for assessing functions of the medulla oblongata.

Methods. Trigeminal evoked potentials induced by electrical stimulation of the infraorbital nerve were recorded from the dorsolateral portion of the medulla oblongata (M-TEP) and the cerebral sensory cortex (C-TEP) in dogs. When the lateral one-sixth portion of the medulla was cut, the amplitude of the M-TEP decreased markedly, but the amplitude of the C-TEP and the somatosensory evoked potential (SSEP) did not decrease. When the lateral one-third portion of the medulla was cut, the amplitude of the SSEP decreased, but that of the C-TEP showed no change. When the medulla was retracted, the amplitude of the M-TEP was more sensitive than that of SSEP. Pathological examinations revealed that retraction force less than 10 g and a reduction in the amplitude of the M-TEP less than 50% were safe.

Conclusions. These results suggest that M-TEPs obtained from the dorsolateral portion of the medulla oblongata by electrical stimulation of the trigeminal nerve are clinically applicable as a new means of intraoperative monitoring of the functions of the medulla oblongata.
Classification and quantification of the petrosal approach to the petroclival region
Authors: Horgan Michael A. , Anderson Gregory J. , Kellogg Jordi X. , Schwartz Marc S. , Spektor Sergey , McMenomey Sean O. , Delashaw Johnny B.
Published: May 2009

Object. The petrosal approach to the petroclival region has been used by a variety of authors in various ways and the terminology has become quite confusing. A systematic assessment of the benefits and limitations of each approach is also lacking. The authors classify their approach to the middle and upper clivus, review the applications for each, and test their hypotheses on a cadaver model by using frameless stereotactic guidance.

Methods. The petrosal approach to the upper and middle clivus is divided into four increasingly morbidity-producing steps: retrolabyrinthine, transcrusal (partial labyrinthectomy), transotic, and transcochlear approaches. Four latexinjected cadaveric heads (eight sides) underwent dissection in which frameless stereotactic guidance was used. An area of exposure 10 cm superficial to a central target (working area) was calculated. The area and length of clival exposure with each subsequent dissection was also calculated.

The retrolabyrinthine approach spares hearing and facial function but provides for only a small window of upper clival exposure. The view afforded by what we have called the transcrusal approach provides for up to four times this exposure. The transotic and transcochlear procedures, although producing more morbidity, add little in terms of a larger clival window. However, with each step, the surgical freedom for manipulation of instruments increases.

Conclusions. The petrosal approach to the upper and middle clivus is useful but should be used judiciously, because levels of morbidity can be high. The retrolabyrinthine approach has limited utility. For tumors without bone invasion, the transcrusal approach provides a much more versatile exposure with an excellent chance of hearing and facial nerve preservation. The transotic approach provides for greater versatility in treating lesions but clival exposure is not greatly enhanced. Transcochlear exposure adds little in terms of intradural exposure and should be reserved for cases in which access to the petrous carotid artery is necessary.
Acromegaly associated with a granular cell tumor of the neurohypophysis: a clinical and histological study
Authors: Losa Marco , Saeger Wolfgang , Mortini Pietro , Pandolfi Claudio , Terreni Maria Rosa , Taccagni Gianluca , Giovanelli Massimo
Published: May 2009

✓ Acromegaly is usually caused by a growth hormone (GH)-secreting pituitary adenoma, and hypersecretion of GH-releasing hormone (GHRH) from a hypothalamic or neuroendocrine tumor accounts for other cases. The authors report on the unusual association of acromegaly with a granular cell tumor of the neurohypophysis.

A 42-year-old woman with a 10-year history of acral enlargement, headache, and menstrual abnormalities was referred to our department for a suspected GH-secreting pituitary adenoma. The patient's basal GH levels were mildly elevated at 4.8 µg/L, were not suppressed in response to an oral glucose tolerance test, and increased paradoxically after administration of thyrotropin-releasing hormone. The patient's insulin-like growth factor—1 (IGF-1) level was elevated at 462 µg/L, whereas a magnetic resonance image of the sella turcica revealed an intra- and suprasellar lesion that was compatible with a diagnosis of pituitary adenoma. A transsphenoidal approach to remove the lesion, which was mainly suprasellar, was successful during a second operative attempt, resulting in the clinical and biochemical regression of the patient's acromegaly. Four months postoperatively, the patient's basal GH level was 0.9 µg/L and her IGF-1 level was 140 µg/L. Histological analysis of the operative specimen demonstrated a granular cell tumor of the neurohypophysis, which when stained proved negative for pituitary hormones and GHRH.

This case represents the first reported association between a granular cell tumor of the neurohypophysis and acromegaly. Granular cell tumor of the neurohypophysis could be added to the restricted list of neoplastic causes of acromegaly secondary to hypersecretion of a GH-releasing substance.
Transcranial—transdural real-time ultrasonography during transsphenoidal resection of a large pituitary tumor
Authors: Atkinson John L. D. , Kasperbauer Jan L. , James E. Meredith , Lane John I. , Nippoldt Todd B.
Published: May 2009

✓ Ultrasonography has been used in neurosurgical operative procedures for several decades. The authors report the case of a large pituitary tumor that was subtotally resected using endoscopy via the transnasal—transsphenoidal approach, with the aid of transcranial real-time ultrasound. To our knowledge, this is the first reported case in which intraoperative transcranial—transdural real-time ultrasound was used to facilitate the resection of a skull base tumor.
Long-term deep brain stimulation in a patient with essential tremor: clinical response and postmortem correlation with stimulator termination sites in ventral thalamus
Authors: Boockvar John A. , Telfeian Albert , Baltuch Gordon H. , Skolnick Brett , Simuni Tanya , Stern Matthew , Schmidt Marie L. , Trojanowski John Q.
Published: May 2009

✓ Essential tremor can be suppressed with chronic, bilateral deep brain stimulation (DBS) of the ventralis intermedius nucleus (Vim), the cerebellar receiving area of the motor thalamus. The goal in this study was to correlate the location of the electrodes with the clinical efficacy of DBS in a patient with essential tremor. The authors report on a woman with essential tremor in whom chronic bilateral DBS directed to the ventral thalamus produced adequate tremor suppression until her death from unrelated causes 16 months after placement of the electrodes. Neuropathological postmortem studies of the brain in this patient demonstrated that both stimulators terminated in the Vim region of the thalamus, and that chronic DBS elicited minor reactive changes confined to the immediate vicinity of the electrode tracks. Although the authors could not identify neuropathological abnormalities specific to essential tremor, they believe that suppression of essential tremor by chronic DBS correlates with bilateral termination of the stimulators in the Vim region of the thalamus.
Henry Schwartz's address to the Society of Neurological Surgeons, May 1998
Authors: Schwartz Henry G. , Smith Kenneth R.
Published: May 2009

✓ In his final address to the Society of Neurological Surgeons, Henry G. Schwartz, M.D., shared his thoughts on mentoring and recalled specific mentors who contributed to his professional life.
Efficacy of neuroradiological imaging, neurological examination, and symptom status in follow-up assessment of patients with high-grade gliomas
Authors: Galanis Evanthia , Buckner Jan C. , Novotny Paul , Morton Roscoe F. , McGinnis William L. , Dinapoli Robert , Schomberg Paula , O'Fallon Judith R.
Published: May 2009

Object. It is standard practice for the oncological follow-up of patients with brain tumors (especially in the setting of clinical trials) to include neurological examination and neuroradiological studies such as computerized tomography (CT) or magnetic resonance (MR) imaging in addition to evaluation of the patients' symptomatology and performance score. The validity of this practice and its impact on the welfare of patients with high-grade gliomas has not been adequately assessed. The purpose of this study is to provide such an assessment.

Methods. The authors studied 231 similarly treated patients who were participating in three prospective North Central Cancer Treatment Group or Mayo Clinic trials who developed progressive disease during follow up. According to the protocol, the symptom status, performance score, results of neurological examination, and CT or MR status were recorded prospectively in each patient at each evaluation (every 6–8 weeks).

At progression, 177 (77%) of 231 patients experienced worsening of their baseline symptoms or they developed new ones. In the remaining 54 asymptomatic patients (23%), neuroradiological imaging revealed the progression. Asymptomatic progression was more likely to be detected on MR imaging compared with CT studies (p < 0.01). In no asymptomatic patient was progression detected on neurological examination alone. The median survival time after tumor recurrence was 13.3 weeks in symptomatic patients compared with 41.7 weeks in the asymptomatic group (p < 0.0001). Asymptomatic patients were more aggressively treated, with surgery (p < 0.0001) and second-line chemotherapy (p < 0.0002). Multivariate analysis of survival time following first progression by using both classification and regression trees and Cox models showed that treatment at recurrence was the most important prognostic variable.

Conclusions. Symptoms are the most frequent indicators of progression in patients with high-grade gliomas (77%). All asymptomatic progressions were detected on neuroradiological studies; MR imaging was more likely than CT scanning to reveal asymptomatic recurrences. Survival after disease progression was significantly longer in asymptomatic patients and could be related both to treatment following progression and to other favorable prognostic factors such as performance score.
Computer-assisted neurosurgery by using a noninvasive vacuum-affixed dental cast that acts as a reference base: another step toward a unified approach in the treatment of brain tumors
Authors: Bale Reto J. , Burtscher Johannes , Eisner Wilhelm , Obwegeser Alois A. , Rieger Michael , Sweeney Reinhart A. , Dessl Andreas , Giacomuzzi Salvatore M. , Twerdy Klaus , Jaschke Werner
Published: May 2009

Object. The purpose of the study was to evaluate the use of the Vogele-Bale-Hohner (VBH) mouthpiece, which is attached to the patient's upper jaw by negative pressure, for patient—image registration and for tracking the patient's head during image-guided neurosurgery.

Methods. A dynamic reference frame (DRF) is reproducibly mounted on the mouthpiece. Reference points, optimally distributed and attached to the mouthpiece, are used for registration in the patient's absence on the day before surgery. In the operating room, the mouthpiece and DRF are precisely repositioned using a vacuum, and the patient's anatomical structures are automatically registered to corresponding ones on the image. Experimental studies and clinical experiences in 10 patients confirmed repeated (rigid body) localization accuracy in the range of 0 to 2 mm, throughout the entire surgery despite movements by the patient.

Conclusions. Because of its noninvasive, rigid, reliable, and reproducible connection to the patient's head, the VBH vacuum-affixed mouthpiece grants the registration device an accuracy comparable to invasive fiducial markers.
Headaches in patients with radiosurgically treated occipital arteriovenous malformations
Authors: Kurita Hiroki , Ueki Keisuke , Shin Masahiro , Kawamoto Shunsuke , Sasaki Tomio , Tago Masao , Kirino Takaaki
Published: May 2009

Object. The goal of this study was to determine the prevalence, characteristics, and radiosurgical outcomes of headaches associated with occipital arteriovenous malformations (AVMs).

Methods. The authors reviewed the medical records of 37 consecutive patients with occipital AVMs who had been treated by radiosurgery to identify the radiological features of the AVMs before and after treatment and the clinical features and outcomes of headaches described in accordance with the criteria of the International Headache Society (IHS).

Thirty-six patients (97.3%) were followed for a mean period of 46.6 months. The median volume of the AVMs was 1.9 cm3, to which a mean radiation dose of 21.6 Gy was delivered. In the entire study group, periodic headaches were found in 17 patients (45.9%), of whom seven (18.9%) suffered from migraines with the characteristic visual aura. Migraine was predominantly found in patients with right-sided (p = 0.038) or laterally located (p = 0.025) AVMs. Factors associated with a higher incidence of any type of headache included larger nidus volume (p = 0.02), tortuous change of feeding artery (p = 0.036), and cortical drainage with reflux in the superior sagittal sinus (p = 0.032). The actuarial rate of angiographic obliteration was 71.6% at 3 years. Headaches resolved or improved in 12 (70.6%) of 17 patients, including six (85.7%) of seven with migraine. The outcome of headache closely correlated with the obliteration results of the AVM (p = 0.002).

Conclusions. A portion of occipital AVMs do cause headaches that satisfy the current IHS criteria for migraine, and the prevalence varies by the topography of the lesion. Radiosurgery can resolve headaches in the majority of treated patients.
Continuous monitoring of regional cerebral blood flow: experimental and clinical validation of a novel thermal diffusion microprobe
Authors: Vajkoczy Peter , Roth Harry , Horn Peter , Lucke Thomas , Thomé Claudius , Hubner Ulrich , Martin Gregory T. , Zappletal Christina , Klar Ernst , Schilling Lothar , Schmiedek Peter
Published: May 2009

Object. Current clinical neuromonitoring techniques lack adequate surveillance of cerebral perfusion. In this article, a novel thermal diffusion (TD) microprobe is evaluated for the continuous and quantitative assessment of intraparenchymal regional cerebral blood flow (rCBF).

Methods. To characterize the temporal resolution of this new technique, rCBF measured using the TD microprobe (TD-rCBF) was compared with rCBF levels measured by laser Doppler (LD) flowmetry during standardized variations of CBF in a sheep model. For validation of absolute values, the microprobe was implanted subcortically (20 mm below the level of dura) into 16 brain-injured patients, and TD-rCBF was compared with simultaneous rCBF measurements obtained using stable xenon-enhanced computerized tomography scanning (sXe-rCBF). The two techniques were compared using linear regression analysis as well as the Bland and Altman method.

Stable TD-rCBF measurements could be obtained throughout all 3- to 5-hour sheep experiments. During hypercapnia, TD-rCBF increased from 49.3 ± 15.8 ml/100 g/min (mean ± standard deviation) to 119.6 ± 47.3 ml/100 g/min, whereas hypocapnia produced a decline in TD-rCBF from 51.2 ± 12.8 ml/100 g/min to 39.3 ± 5.6 ml/100 g/min. Variations in mean arterial blood pressure revealed an intact autoregulation with pressure limits of approximately 65 mm Hg and approximately 170 mm Hg. After cardiac arrest TD-rCBF declined rapidly to 0 ml/100 g/min. The dynamics of changes in TD-rCBF corresponded well to the dynamics of the LD readings. A comparison of TD-rCBF and sXe-rCBF revealed a good correlation (r = 0.89; p <0.0001) and a mean difference of 1.1 ± 5.2 ml/100 g/min between the two techniques.

Conclusions. The novel TD microprobe provides a sensitive, continuous, and real-time assessment of intraparenchymal rCBF in absolute flow values that are in good agreement with sXe-rCBF measurements. This study provides the basis for the integration of TD-rCBF into multimodal monitoring of patients who are at risk for secondary brain injury.
Survival of adult rat retinal ganglion cells with regrown axons in peripheral nerve grafts: a comparison of graft attachment with suture or fibrin glue
Authors: Robinson Grant A. , Madison Roger D.
Published: May 2009

Object. The goal of this study was to examine whether the method of attachment of a peripheral nerve graft would have an effect on retinal ganglion cell (RGC) regeneration.

Methods. The number of adult rat RGCs with regrown axons in a peripheral nerve graft was compared under two grafting conditions: 1) attachment of the graft to the optic nerve stump made using a suture; and 2) attachment made using fibrin glue. Counts of RGCs retrogradely labeled with FluoroGold from the grafts 1 month after attachment revealed approximately seven times the number of RGCs in the fibrin-glue group compared with the suture group.

Conclusions. The use of fibrin glue may be a useful tool for enhancing the regrowth of central nervous system neuron axons into peripheral nervous system grafts.
Wild-type p53—dependent etoposide-induced apoptosis mediated by caspase-3 activation in human glioma cells
Authors: Yin Dali , Tamaki Norihiko , Kokunai Takashi
Published: May 2009

Object. In an attempt to understand the roles of several apoptosis-related genes in human glioma cells, the authors investigated the relationship of wild-type p53, interleukin-1β—converting enzyme (ICE), caspase-3 (CPP32), bax, and bcl-2 to the apoptotic response of three glioma cell lines after treatment with etoposide.

Methods. A human glioma cell line (U-87MG) that expresses wild-type p53, one that expresses mutant p53 (T-98G), and a T-98G derivative (T-98G/p53) that was transfected with a wild-type p53 expression vector (pCDM8-p53/neo) were used. Cell growth inhibition in response to etoposide was quantified using a modified methylthiazol tetrazolium colorimetric assay. Induction of apoptosis was evaluated using Hoechst 33258 staining and a DNA fragmentation assay. To study the expression of the apoptosis-related proteins and messenger RNAs in the three glioma cell lines, Western blotting and polymerase chain reaction were performed. A caspase assay and Western blot analysis were used to assess CPP32 and ICE protease activity. A CPP32 inhibition assay was used to determine whether a specific CPP32 inhibitor, DEVD-CHO, affects the apoptosis induced by etoposide in malignant glioma cells. Etoposide significantly inhibited the growth of U-87MG and T-98G/p53 cells in a dose-dependent manner compared with the growth of the T-98G cells. Treatment with low concentrations of etoposide resulted in the increased expression of wild-type p53; it also initiated CPP32 activity and induced apoptosis in the U-87MG cells. Apoptosis was not induced in T-98G cells at low concentrations of etoposide, although it was induced at high concentrations. Furthermore, low concentrations of etoposide also induced apoptosis in the T-98G/p53 cells by enhancing the expression of transfected wild-type p53, decreasing the expression of bcl-2, and activating CPP32 activity. However, etoposide did not alter the expression of bax and did not initiate ICE activity in these three glioma cell lines. Etoposide-induced apoptosis can be suppressed by the CPP32 inhibitor DEVD-CHO.

Conclusions. These findings indicate that wild-type p53, CPP32, and bcl-2 may mediate apoptosis induced by etoposide. Forced expression of wild-type p53 increases etoposide cytotoxicity in human glioma cells by inducing apoptosis and may have important therapeutic implications.
Effect of initially limited resuscitation in a combined model of fluid-percussion brain injury and severe uncontrolled hemorrhagic shock
Authors: Stern Susan A. , Zink Brian J. , Mertz Michelle , Wang Xu , Dronen Steven C.
Published: May 2009

Object. Studies of isolated uncontrolled hemorrhage have indicated that initial limited resuscitation improves survival. Limited resuscitation has not been studied in combined traumatic brain injury and uncontrolled hemorrhage. In this study the authors evaluated the effects of limited resuscitation on outcome in combined fluid-percussion injury (FPI) and uncontrolled hemorrhage.

Methods. Twenty-four swine weighing 17 to 24 kg each underwent FPI (3 atm) and hemorrhage to a mean arterial pressure (MAP) of 30 mm Hg in the presence of a 4-mm aortic tear. Group I (nine animals) was initially resuscitated to a goal MAP of 60 mm Hg; Group II (nine animals) was resuscitated to a goal MAP of 80 mm Hg; and Group III (control; six animals) was not resuscitated. After 60 minutes, the aortic hemorrhage was controlled and the animals were resuscitated to baseline physiological parameters and observed for 150 minutes.

Mortality rates were 11%, 50%, and 100% for Groups I, II, and III, respectively (Fisher's exact test; p = 0.002). The total hemorrhage volume was greater in Group II (69 ± 32 ml/kg), as compared with Group I (41 ± 18 ml/kg) and Group III (37 ± 3 ml/kg) according to analysis of variance (p < 0.05). In surviving animals, cerebral perfusion pressure, cerebral blood flow (CBF), cerebral venous O2 saturation (ScvO2), and cerebral metabolic rate of O2 did not differ among groups. Although CBF was approximately 50% of baseline during the period of limited resuscitation in Group I, ScvO2 remained greater than 60%, and arteriovenous O2 differences remained within normal limits.

Conclusions. In this model of FPI and uncontrolled hemorrhage, early aggressive resuscitation, which is currently recommended, resulted in increased hemorrhage and failure to optimize cerebrovascular parameters. In addition, a 60-minute period of moderate hypotension (MAP = 60 mm Hg) was well tolerated and did not compromise cerebrovascular hemodynamics, as evidenced by physiological parameters that remained within the limits of cerebral autoregulation.
Immediate coma following inertial brain injury dependent on axonal damage in the brainstem
Authors: Smith Douglas H. , Nonaka Masahiro , Miller Reid , Leoni Matthew , Chen Xiao-Han , Alsop David , Meaney David F.
Published: May 2009

Object. Immediate and prolonged coma following brain trauma has been shown to result from diffuse axonal injury (DAI). However, the relationship between the distribution of axonal damage and posttraumatic coma has not been examined. In the present study, the authors examine that relationship.

Methods. To explore potential anatomical origins of posttraumatic coma, the authors used a model of inertial brain injury in the pig. Anesthetized miniature swine were subjected to a nonimpact-induced head rotational acceleration along either the coronal or axial plane (six pigs in each group). Immediate prolonged coma was consistently produced by head axial plane rotation, but not by head coronal plane rotation. Immunohistochemical examination of the injured brains revealed that DAI was produced by head rotation along both planes in all animals. However, extensive axonal damage in the brainstem was found in the pigs injured via head axial plane rotation. In these animals, the severity of coma was found to correlate with both the extent of axonal damage in the brainstem (p < 0.01) and the applied kinetic loading conditions (p < 0.001). No relationship was found between coma and the extent of axonal damage in other brain regions.

Conclusions. These results suggest that injury to axons in the brainstem plays a major role in induction of immediate posttraumatic coma and that DAI can occur without coma.
Multiple intracranial juvenile xanthogranulomas
Authors: Boström Jan , Janßen Gisela , Messing-Jünger Martina , Felsberg Jörg U. , Neuen-Jacob Eva , Engelbrecht Volkher , Lenard Hans-Gerd , Bock Wolfgang J. , Reifenberger Guido
Published: May 2009

✓ The authors report on an 11-year-old boy in whom proptosis of the eye caused by a benign intraosseous xanthofibroma of the left orbital wall became clinically apparent at the age of 4 years. Two years later he developed bilateral papilledema, at which time computerized tomography and magnetic resonance studies revealed multiple enhancing intracranial lesions. The largest mass was located in the left middle fossa; other lesions were located at the tentorium cerebelli, in both lateral ventricles, near the superior sagittal sinus, and extracranially near the left jugular vein. The mass in the left middle fossa was resected and diagnosed as juvenile xanthogranuloma (JXG). Thirty months later, the patient again became symptomatic, exhibiting behavioral abnormalities and a decrease in mental powers. At that time, the two remaining lesions in both lateral ventricles had grown enough to cause trapping of the temporal horns and raised intracranial pressure. These lesions were successively resected and histopathologically confirmed to be JXGs. However, resection of the second intraventricular lesion was complicated by postoperative bilateral amaurosis, presumably caused by postdecompression optic neuropathy. According to a review of the literature, fewer than 20 patients with JXG involving the central nervous system have been reported. The patient described in this report is the first in whom multiple intracranial JXGs developed in the absence of cutaneous manifestations. Although JXGs are biologically benign lesions, the treatment of patients with multifocal and/or progressive intracranial manifestations is problematic.
Comparison of two commercially available near-infrared spectroscopy instruments for cerebral oximetry
Authors: Cho Hun , Nemoto Edwin M. , Sanders Mark , Fernandez Karl , Yonas Howard
Published: May 2009

✓ Two near-infrared spectroscopy (NIRS) devices were compared with regard to their responses to changes in cerebral hemoglobin oxygenation induced by hypoxia and hypercapnia in five healthy volunteers.

Sensors belonging to each NIRS device were placed on opposite sides of the volunteer's forehead. The INVOS3100A device, approved by the United States Food and Drug Administration, records the percentage of oxyhemoglobin (HbO2) saturation and the investigational NIRO500 device records absolute changes in HbO2, deoxyhemoglobin, and total hemoglobin in micromolar concentrations referenced to an arbitrary baseline. The volunteers breathed separate mixtures of 7% CO2 in O2 and 10% O2 for 5 minutes in random order. Arterial blood pressure, end-tidal CO2 (ETCO2), arterial O2 saturation, and electrocardiographic data were continuously monitored.

Hypercapnia increased (p < 0.01) ETCO2 from 42 ± 2 to 56 ± 3 mm Hg (mean ± standard deviation), resulting in a 7.3 ± 0.2% increase (p < 0.005) in cerebral HbO2 saturation detected by the INVOS3100A device and an 11.6 ± 3 µM increase (p < 0.0008) in HbO2 detected by the NIRO500. Hypoxia decreased (p < 0.01) arterial HbO2 saturation from 98 ± 1 to 87 ± 3%, causing a 5.1 ± 1.2% decrease (p < 0.01) in the percentage of HbO2 saturation detected by the INVOS3100A device and a 9.7 ± 6.3 µM decrease in HbO2 detected by the NIRO500.

The responses of the NIRO500 and the INVOS3100A instruments to changes in cerebral oxygenation resulting from hypercapnia and hypoxia were generally similar; however, responses tended to be greater when recorded by the NIRO500 device, perhaps because, unlike the INVOS3100A device, the NIRO500 does not correct for skin and bone contamination.
The remodeling technique of balloon-assisted Guglielmi detachable coil placement in wide-necked aneurysms: experience at the University of Illinois at Chicago
Authors: Aletich Victor A. , Debrun Gerard M. , Misra Mukesh , Charbel Fady , Ausman James I.
Published: May 2009

Object. Reports in the literature have offered discussions of the feasibility, efficacy, and safety of balloon-assisted Guglielmi detachable coil (GDC) placement in wide-necked intracranial aneurysms, which was first described by Jacques Moret as the “remodeling technique.” In this article the authors summarize their results in a subset of aneurysms treated with GDCs using the remodeling technique.

Methods. This report contains a retrospective analysis of 72 patients with 75 aneurysms who underwent 79 endovascular procedures performed using the remodeling technique. Morphological outcome was determined at the end of each procedure and by reviewing available follow-up angiograms. Clinical assessments and outcomes are reported using a modified Glasgow Outcome Scale.

Coils were placed in 66 (88%) of 75 aneurysms selected for treatment. In eight aneurysms (11%) treatment failures occurred due to the tortuosity of the vessel used to reach the aneurysms or because of balloon inadequacies.

Incorporating all available follow-up data the authors found that 50 (78%) of 64 aneurysms were completely or subtotally (> 95%) occluded and eight (12%) of 64 were incompletely (< 95%) occluded. Since the time of coil placement, eight aneurysms have progressed to complete occlusion and another five have exhibited progressive thrombosis on follow-up angiograms. In three aneurysms there has been neck remnant growth. Surgical clipping was performed to treat six aneurysms after an initial coil placement procedure. Permanent incidences of morbidity were limited to four patients and there were three deaths directly related to the procedure.

Conclusions. The remodeling technique shows promise in increasing the number of cerebral aneurysms amenable to treatment by endovascular coil placement, and offers an alternative approach to aneurysms that have met with failed surgical treatment or are surgically inaccessible. Long-term follow-up review is needed to determine the final outcome of aneurysms treated by this technique.