bluuebunny/crossref_metadata_2025 huggingface dataset:
Hyperglycemia, excess weight, and history of hypertension as risk factors for poor outcome and cerebral infarction after aneurysmal subarachnoid hemorrhage
Authors: Juvela Seppo , Siironen Jari , Kuhmonen Johanna
Published: May 2009

Object. Stress-induced hyperglycemia has been shown to be associated with poor outcome after aneurysmal subarachnoid hemorrhage (SAH). The authors prospectively tested whether hyperglycemia, independent of other factors, affects patient outcomes and the occurrence of cerebral infarction after SAH.

Methods. Previous diseases, health habits, medications, clinical condition, and neuroimaging variables were recorded for 175 patients with SAH who were admitted to the hospital within 48 hours after bleeding. The plasma level of glucose was measured at admission and the fasting value of glucose was measured in the morning after aneurysm occlusion. Factors found to be independently predictive of patient outcomes at 3 months after SAH onset and the appearance of cerebral infarction were tested by performing multiple logistic regression.

Plasma glucose values at admission were found to be associated with patient age, body mass index (BMI), history of hypertension, clinical condition, amount of subarachnoid or intraventricular blood, shunt-dependent hydrocephalus, outcome variables, and the appearance of cerebral infarction. When considered independently of age, clinical condition, or amount of subarachnoid, intraventricular, or intracerebral blood, the plasma glucose values at admission predicted poor outcome (per millimole/liter the odds ratio [OR] was 1.24 with a 95% confidence interval [CI] of 1.02–1.51). After an adjustment was made for the amount of subarachnoid blood, the clinical condition, and the duration of temporary artery occlusion during surgery, the BMI was found to be a significant predictor (per kilogram/square meter the OR was 1.15 with a 95% CI of 1.02–1.29) for the finding of cerebral infarction on the follow-up computerized tomography scan. Hypertension (OR 3.11, 95% CI 1.11–8.73)—but not plasma glucose (OR 1.06, 95% CI 0.87–1.29)—also predicted the occurrence of infarction when tested instead of the BMI.

Conclusions. Independent of the severity of bleeding, hyperglycemia at admission seems to impair outcome, and excess weight and hypertension appear to elevate the risk of cerebral infarction after SAH.
Self-inflicted submental and transoral gunshot wounds that produce nonfatal brain injuries: management and prognosis
Authors: Kriet J. David , Stanley Robert B. , Grady M. Sean
Published: May 2009

Object. Penetrating brain injuries caused by self-inflicted gunshot wounds are very often fatal and survivors suffer serious disabilities. Recognition of a possibly more favorable prognosis for a specific type of injury, the submental or transoral handgun or low-energy rifle wound, prompted the authors to review their experience with patients who had attempted suicide in this manner.

Methods. The records of 11 consecutive patients seen over a 10-year period (1992–2001) were retrospectively reviewed. Handguns were used by eight patients and .22 caliber rifles by the others. The patients presented with predominantly unilateral frontal brain injuries that required urgent attention. One elderly patient who had made an advance directive concerning care died. All other patients underwent craniotomy and repair of associated ophthalmological and maxillofacial injuries. Follow-up review ranged from 9 months to 3 years, during which time there were no repeated suicide attempts. All but one patient expressed satisfaction with their appearance and returned to a self-sufficient lifestyle.

Conclusions. Self-inflicted submental and transoral handgun and low-energy rifle wounds may produce serious but survivable brain injuries if the path of the bullet is limited to the frontal area. Early aggressive management of brain, dural, and craniomaxillofacial injuries should return the patient to a highly functional neurological status and restore an acceptable outward appearance. Outcomes, therefore, appear to be much better for these patients than for most patients with a penetrating brain injury due to a self-inflicted gunshot wound.
Frameless stereotactic placement of depth electrodes in epilepsy surgery
Authors: Mehta Ashesh D. , Labar Douglas , Dean Andrew , Harden Cynthia , Hosain Syed , Pak Jayoung , Marks David , Schwartz Theodore H.
Published: May 2009

Object. Depth electrodes are useful in the identification of deep epileptogenic foci. Computerized tomography—magnetic resonance (CT/MR)— and angiography-guided frame-based techniques are safe and accurate but require four-point skull fixation that limits cranial access for the placement of additional grids and strips. The authors investigated the viability and accuracy of placing depth electrodes by using a commercially available frameless system.

Methods. A slotted, custom-designed adapter was built to interface with the StealthStation Guide Frame-DT and 960-525 StealthFighter. The Cranial Navigation software was used to plan the trajectory and entry site based on preoperative spoiled gradient MR imaging studies. Forty-one depth electrodes were placed in 51 targets in 20 patients. Thirty-one of these electrodes were inserted through the temporal neocortex following craniotomy and placement of subdural grids, whereas 10 were placed through burr holes. All electrodes had contact either within (71%) or touching (29%) the target, 50 of which (98%) provided adequate recordings. Although the mean distance of the distal electrode contact from the intended target was 3.1 ± 0.5 mm, the mean distance to the edge of the anatomical structure was 0.4 ± 0.9 mm. Placement via the laterotemporal approach was significantly (p < 0.001) more accurate than that via the occipitotemporal approach. No complication occurred.

Conclusions. Depth electrodes can be placed safely and accurately by using a commercially available frameless stereotactic navigation system and a custom-made adapter. Depth electrode placement to record ictal onsets during epilepsy surgery only requires the contacts to touch rather than to reside within the intended structure. The laterotemporal approach is a more accurate method of placing electrodes than is the occipitotemporal one, likely due to the increased distance from the entry point to the target.
Delayed cell death related to acute cerebral blood flow changes following subarachnoid hemorrhage in the rat brain
Authors: Prunell Giselle F. , Svendgaard Niels-Aage , Alkass Kanar , Mathiesen Tiit
Published: May 2009

Object. The authors tested the hypotheses that subarachnoid hemorrhage (SAH) leads to delayed cell death with the participation of apoptotic-like mechanisms and is influenced by the degree of acute decrease in the cerebral blood flow (CBF) following hemorrhage.

Methods. Subarachnoid hemorrhage was induced in rats by endovascular perforation of the internal carotid artery or injection of blood into the prechiasmatic cistern. Cerebral blood flow was measured using laser Doppler flowmetry for 60 minutes. Brain sections stained with terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) showed DNA fragmentation at 2 and 7 days after both methods of inducing SAH in one third to two thirds of the surviving animals in the different experimental groups. More than 80% of the TUNEL-positive cells were neuron-specific nuclear protein—positive (neurons), but immunoreactivity to glial fibrillary acidic protein (astrocytes) and transferrin (oligodendrocytes) were markedly decreased in TUNEL-positive areas. Most of the TUNEL-positive cells displayed chromatin condensation and/or blebs and immunostained for increased Bax; approximately 50% of them were immunoreactive to cleaved caspase-3 and a few to Bcl-2. The duration of the acute CBF decrease below 30% of the baseline level was related to the degree of TUNEL staining.

Conclusions. Subarachnoid hemorrhage resulted in delayed cell death in a large proportion, but not all, of the surviving animals. The acute CBF decrease was related to the degree of subsequent cell death. These findings indicated the relevance of apoptotic-like pathways. There appears to be a temporal therapeutic window during which adequate treatment might reduce the final damage following SAH.
Delayed treatment with magnesium: reduction of brain infarction and improvement of electrophysiological recovery following transient focal cerebral ischemia in rats
Authors: Lee E-Jian , Lee Ming-Yang , Chang Guan-Liang , Chen Li-Hsuan , Hu Yu-Ling , Chen Tsung-Ying , Wu Tian-Shung
Published: May 2009

Object. The authors examined whether delayed treatment with Mg++ would reduce brain infarction and improve electrophysiological and neurobehavioral recovery following cerebral ischemia—reperfusion.

Methods. Male Sprague—Dawley rats were subjected to right middle cerebral artery occlusion for 90 minutes followed by 72 hours of reperfusion. Magnesium sulfate (750 µmol/kg) or vehicle was given via intracarotid infusion at the beginning of reperfusion. Neurobehavioral outcome and somatosensory evoked potentials (SSEPs) were examined before and 72 hours after ischemia—reperfusion. Brain infarction was assessed after the rats had died.

Before ischemia—reperfusion, stable SSEP waveforms were recorded after individual fore- and hindpaw stimulations. At 72 hours of perfusion the SSEPs recorded from ischemic fore- and hindpaw cortical fields were depressed in vehicle-injected animals and the amplitudes decreased to 19 and 27% of baseline, respectively (p < 0.001). Relative to controls, the amplitudes of SSEPs recorded from both ischemic fore- and hindpaw cortical field in the Mg++-treated animals were significantly improved by 23% (p < 0.005) and 39% (p < 0.001) of baselines, respectively. In addition, Mg++ improved sensory and motor neurobehavioral outcomes by 34% (p < 0.01) and 24% (p < 0.05), respectively, and reduced cortical (p < 0.05) and striatal (p < 0.05) infarct sizes by 42 and 36%, respectively.

Conclusions. Administration of Mg++ at the commencement of reperfusion enhances electrophysiological and neurobehavioral recovery and reduces brain infarction after cerebral ischemia—reperfusion. Because Mg++ has already been used clinically, it may be worthwhile to investigate it further to see if it holds potential benefits for patients with ischemic stroke and for those who will undergo carotid endarterectomy.
Acute microvascular platelet aggregation after subarachnoid hemorrhage
Authors: Sehba Fatima A. , Mostafa Gulam , Friedrich Victor , Bederson Joshua B.
Published: May 2009

Object. The mechanisms underlying acute cerebral ischemia after subarachnoid hemorrhage (SAH) are not well established. Platelets aggregate within major cerebral vessels hours after SAH, but this has not been studied in the microvasculature. Platelet aggregates within the microvasculature could mechanically obstruct the lumen and initiate events that injure vessel structure. In the present study the authors examined the hypothesis that platelets aggregate within the cerebral microvasculature acutely after SAH.

Methods. Subarachnoid hemorrhage was induced in the rat by using the endovascular perforation model. The animals were killed between 10 minutes and 48 hours after SAH. Immunostaining for the platelet surface receptor glycoprotein (GP)IIb/IIIa, which mediates platelet aggregation, was used to detect platelet aggregation. Sham-operated animals were used as controls.

The GPIIb/IIIa immunoreactive platelet aggregates were abundant in the microvasculature of the basal and frontal cortex, striatum, and hippocampus 10 minutes after SAH. These aggregates decreased in number from 1 to 6 hours post-SAH and then increased to a peak at 24 hours. No immunoreactive aggregates were observed 48 hours after SAH.

Conclusions. The data indicate that widespread platelet aggregation occurs very rapidly in response to SAH followed by a decrease within 6 hours and a subsequent increase 24 hours after SAH. Microvascular platelet aggregates may contribute to decreased cerebral blood flow and ischemic injury after SAH via a number of mechanisms.
Cerebrovascular characterization of clazosentan, the first nonpeptide endothelin receptor antagonist clinically effective for the treatment of cerebral vasospasm. Part I: Inhibitory effect on endothelinA receptor—mediated contraction
Authors: Vatter Hartmut , Zimmermann Michael , Tesanovic Veronika , Raabe Andreas , Schilling Lothar , Seifert Volker
Published: May 2009

Object. The central role of endothelin (ET)—1 in the development of cerebral vasospasm after subarachnoid hemorrhage is indicated by the successful treatment of this vasospasm in several animal models by using selective ETA receptor antagonists. Clazosentan is a selective ETA receptor antagonist that provides for the first time clinical proof that ET-1 is involved in the pathogenesis of cerebral vasospasm. The aim of the present investigation was, therefore, to define the pharmacological properties of clazosentan that affect ETA receptor—mediated contraction in the cerebrovasculature.

Methods. Isometric force measurements were performed in rat basilar artery (BA) ring segments with (E+) and without (E−) endothelial function. Concentration effect curves (CECs) were constructed by cumulative application of ET-1 or big ET-1 in the absence or presence of clazosentan (10−9, 10−8, and 10−7 M). The inhibitory potency of clazosentan was determined by the value of the affinity constant (pA2).

The CECs for contraction induced by ET-1 and big ET-1 were shifted to the right in the presence of clazosentan in a parallel dose-dependent manner, which indicates competitive antagonism. The pA2 values for ET-1 were 7.8 (E+) and 8.6 (E−) and the corresponding values for big ET-1 were 8.6 (E+) and 8.3 (E−).

Conclusions. The present data characterize clazosentan as a potent competitive antagonist of ETA receptor—mediated constriction of the cerebrovasculature by ET-1 and its precursor big ET-1. These functional data may also be used to define an in vitro profile of an ET receptor antagonist with a high probability of clinical efficacy.
Cerebrovascular characterization of clazosentan, the first nonpeptide endothelin receptor antagonist shown to be clinically effective for the treatment of cerebral vasospasm. Part II: Effect on endothelinB receptor—mediated relaxation
Authors: Vatter Hartmut , Zimmermann Michael , Tesanovic Veronika , Raabe Andreas , Seifert Volker , Schilling Lothar
Published: May 2009

Object. The disturbed balance between nitric oxide and endothelin (ET)—1 in the cerebrovasculature seems to play a major role in the development of cerebral vasospasm after subarachnoid hemorrhage. Endothelin-1 represents the contractile part in this balance. In addition to the prevailing ETA receptor—dependent contractile effect, ET-1 also has ETB receptor—mediated vasodilatory attributes. The aim of the present study was to define the actual selectivity of clazosentan, the first putative highly ETA receptor—selective antagonist clinically proven to be effective in the treatment of vasospasm in the cerebrovasculature.

Methods. Rat basilar artery ring segments with endothelial function were used for the measurement of isometric force. Concentration effect curves were constructed by cumulative application of sarafotoxin S6c, ET-1, or big ET-1 in the presence or absence of clazosentan (10−9 to 10−6 M) after a precontraction was induced by prostaglandin F2α. The inhibition by clazosentan was estimated by the value of the affinity constant (pA2).

The relaxation induced by sarafotoxin S6c, ET-1, and big ET-1 was inhibited in a competitive manner by clazosentan, yielding pA2 values of 7.1, 6.7, and 6.5, respectively. The selectivity to the ETA receptor in the cerebrovascular system was approximately two logarithmic units.

Conclusions. The present investigation shows a competitive inhibition of ETB receptor—mediated relaxation in cerebral vessels by clazosentan in therapeutically relevant concentrations. Thus, additional clinical trials should be undertaken to evaluate clazosentan concentrations in cerebrospinal fluid. Furthermore, the present data may be taken to describe the pharmacological properties for an ET receptor antagonist specifically tailored for the treatment of pathological conditions of impaired cerebral blood flow.
Suppression of secondary generalization of limbic seizures by stimulation of subthalamic nucleus in rats
Authors: Usui Naotaka , Maesawa Satoshi , Kajita Yasukazu , Endo Otone , Takebayashi Shigenori , Yoshida Jun
Published: May 2009

Object. Deep brain stimulation (DBS) of subcortical nuclei such as the subthalamic nucleus (STN) or the substantia nigra pars reticulata (SNR) may provide an alternative therapy for intractable epilepsy. The authors attempted to evaluate the antiepileptic effects of DBS to these structures in an experimental seizure model.

Methods. Three groups of rats were prepared. In the first two groups, the rats underwent unilateral implantation of stimulation electrodes in the STN (six rats) or the SNR (six rats). A control group received no electrodes (six rats). Kainic acid (KA) was systemically administered to induce limbic seizures, which started with focal seizures and became generalized secondarily. High-frequency electrical stimulation of the STN or SNR was begun immediately after KA administration, and changes on electroencephalography (EEG) and the magnitude of clinical seizures were evaluated. Results showed that STN stimulation significantly reduced the duration of generalized seizures on EEG, although the total duration of seizures (generalized plus focal seizures) was unchanged. The duration of focal seizures on EEG was prolonged by STN DBS, a result possibly due to the suppression of secondary generalization. In addition, STN DBS reduced the severity of clinical seizures. On the other hand, stimulation of the SNR demonstrated no effect.

Conclusions. Unilateral STN DBS showed significant suppression of the secondary generalization of limbic seizures. Note, however, that SNR DBS was less effective, which implies that in addition to the nigral control of the epilepsy system, another antiepileptic mechanism such as antidromic stimulation of the corticosubthalamic pathway should be considered.
Prolonged intrathecal baclofen withdrawal syndrome
Authors: Douglas Andrea F. , Weiner Howard L. , Schwartz David R.
Published: May 2009

✓ The authors describe a patient who experienced a prolonged course of intrathecal baclofen withdrawal syndrome after removal of an implantable baclofen pump for treatment of pump infection and meningitis. The current literature outlines management options for the acute management of this syndrome. In this report the authors discuss the long-term presentation of this syndrome and suggest a treatment strategy for management of the syndrome.

A 37-year-old man who presented with a baclofen pump infection and meningitis experienced acute onset of intrathecal baclofen withdrawal syndrome 12 hours after the pump had been surgically removed. The patient's symptoms evolved into a severe, treatment-refractory withdrawal syndrome lasting longer than 1 month.

Oral baclofen replacement with adjunctive administration of parenteral γ-aminobutyric acid agonists only served to stabilize the patient's critical condition throughout his hospital course. Replacement of the baclofen pump and restoration of intrathecal delivery of the medication was necessary to trigger the patient's dramatic recovery and complete reversal of the withdrawal syndrome within approximately 48 hours.

These findings indicate that a more direct method of treating infected baclofen pumps than immediate surgical removal is necessary to prevent the onset of intrathecal baclofen withdrawal syndrome. Various options for preventing the onset of the syndrome while simultaneously treating the infection are discussed.
Enlarged perivascular spaces mimicking multicystic brain tumors
Authors: Rohlfs Jochen , Riegel Thomas , Khalil Munzir , Iwinska-Zelder Joanna , Mennel Hans-Dieter , Bertalanffy Helmut , Hellwig Dieter
Published: May 2009

✓ The authors present two cases in which enlarged Virchow—Robin spaces were located in the basal ganglia and the thalamomesencephalic region. The incidence of such huge cystic lesions is extremely rare. The expanding nature of these lesions, demonstrated by the patients' progressive symptoms due to compression of the adjacent brain parenchyma and obstructive hydrocephalus, mimicked that of brain tumors. The two patients were successfully treated by neuroendoscopic cystocisternostomy or ventriculocystostomy. To the authors' knowledge there have been only two published reports on expanding Virchow—Robin spaces that produced a compressive effect or consequent hydrocephalus and were directly fenestrated using neuroendoscopic techniques. Neuroendoscopy appears to offer an effective surgical option in the treatment of symptomatic Virchow—Robin spaces.
Resolution of neurogenic arterial hypertension after suboccipital decompression for Chiari malformation
Authors: Naderi Sait , Acar Feridun , Acar Göksemin , Men Süleyman
Published: May 2009

✓ A Chiari malformation Type I may remain asymptomatic until the patient has reached adulthood and acute presentation of symptoms occurs. In several clinical and experimental studies it has been shown that essential hypertension is associated with vascular compression of the brainstem, particularly of the rostral ventrolateral medulla oblongata. Nevertheless, two cases of Chiari malformation and neurogenic arterial hypertension have been reported. In this article the authors describe a patient with Chiari malformation Type I and neurogenic arterial hypertension. A simple suboccipital decompression not only provided neurological improvement, but also led to resolution of the hypertension.

In cases of Chiari malformation and concomitant neurogenic arterial hypertension careful preoperative clinical and neuroimaging assessments may reveal the cause of the arterial hypertension. Resolution of neurogenic arterial hypertension may be expected even in a case of simple suboccipital decompression.
Juvenile psammomatoid ossifying fibroma of the neurocranium
Authors: Hasselblatt Martin , Jundt Gernot , Greiner Christoph , Rama Burckhard , Schmäl Frank , Iglesias-Rozas José R. , van de Nes Johannes A. P. , Paulus Werner
Published: May 2009

✓ Juvenile psammomatoid ossifying fibroma (JPOF) is a benign fibroosseous lesion predominantly arising within the paranasal sinuses in children and young adults. Neurocranial occurrence is exceedingly rare and a location within the neurocranial portion of the temporal bone has not been described. The authors report on one case of sinonasal JPOF secondarily extending into the cranial cavity and three cases primarily affecting the neurocranial bones to increase clinical awareness of this uncommon tumor, which may be easily mistaken for meningioma. Moreover, the absence of activating missense mutations of the GNAS1 gene in two cases strongly argues against a relationship between JPOF and fibrous dysplasia.
Brain metastasis from cutaneous squamous cell carcinoma of the dorsum
Authors: Salvati Maurizio , Caroli Emanuela , Paone Cristina , Frati Alessandro , Ferrante Luigi , Giangaspero Felice , Delfini Roberto
Published: May 2009

✓ The majority of cutaneous squamous cell carcinoma (SCC) are diagnosed early and cured using local treatment, although a minority of cases metastasize to regional structures. In this report the authors describe an unknown feature of skin SCC, namely, distant brain metastasis. This 54-year-old man, who had undergone surgery for moderately differentiated SCC of the dorsum (T2N0M0 stage), was admitted to our institution 11 months later with headache, vomiting, and ataxia. A magnetic resonance image documented a cerebellar lesion, which was totally removed. Results of histological studies revealed SCC. The patient received whole-brain radiotherapy (30 Gy over 2 weeks using a linear accelerator). A metastatic work-up showed enlarged inguinal and para-aortic lymph nodes that were histologically examined using excisional biopsy. Inguinal lymph nodes were tumor-positive and were dissected. The patient was subjected to two cycles of chemotherapy with cisplatin (75 mg/m2). After 3 months, a significant reduction in the size of the para-aortic lymph nodes was documented on control computerized tomography studies. Although the described case is unique, knowledge of the potential for this uncommon behavior in cutaneous SCC may be useful, especially because of its increasing incidence.
Computational model for the estimation of the extracranial doses received during Leksell gamma knife model C treatment
Authors: Majali Mustafa , Novotny Josef , Novotny Josef
Published: May 2009

Object. Extracranial doses received by patients undergoing Leksell gamma knife surgery (GKS) can be of clinical concern. Therefore, the ability to preestimate peripheral doses received outside the treatment field during the GKS would be beneficial and could be used for the optimization of treatment planning by providing a reference for practitioners to calculate the extracranial dose burden to the body before the start of treatment.

Methods. A dose of 40 Gy was delivered to the Rando phantom in a single fraction to a midline hypothetical target close to the center of the skull. Treatment planning was performed for multiple isocenters with a prescription to the 50% isodose of each collimator. Treatment plans were produced for 1, 5, 10, 15, and 20 shots, keeping the same dose and dose distribution at different target volumes. An automatic positioning system was used for positioning the phantom during the treatment. The doses to different organs were measured during GKS using a thermoluminescent dosimeter. In vivo measurements were also made in 200 patients who underwent GKS with the model C unit for different diagnoses at Na Homolce Hospital.

Conclusions. The peripheral dose depended on the collimator size with a logarithmic dependence on collimator size and a linear dependence on the number of shots. This model can be used for the estimation of peripheral doses with a total error less than 20%. This information can help clinicians with treatment planning optimization, especially in patients with long survival expectancy.
Low-grade gliomas treated by fractionated gamma knife surgery
Authors: Simonová Gabriela , Novotny Josef , Liscák Roman
Published: May 2009

Object. The authors sought to evaluate local tumor control, complications, and progression-free survival in patients harboring low-grade gliomas who were treated with Leksell gamma knife surgery (GKS).

Methods. During a 6-year period 70 patients were treated for verified low-grade gliomas (Grade I or II) by GKS. Statistical analysis was based on 68 patients; two patients were lost to follow up. The median patient age was 17 years. The median target volume was 4200 mm.3 The median prescription dose was 25 Gy. The median number of fractions was five. Ninety-five percent of patients were treated in five daily fractions.

Partial or complete tumor regression was achieved in 83% of patients with a median time to response of 18 months. There was moderate acute or late toxicity in not more than 5% of patients. In this series the progression-free survival was 92% at 3 years and 88% at 5 years.

Conclusions. Relatively high local tumor control with minimal complications was achieved.
A comparison of the gamma knife model C and the Automatic Positioning System with Leksell model B
Authors: Tlachacova Daniela , Schmitt Michal , Novotny Josef , Novotny Josef , Majali Mustafa , Liscak Roman
Published: May 2009

Object.The authors sought to compare the quality of treatment planning, radiation protection, and the time taken for treatment in the Leksell gamma knife model B with that using the model C Automatic Positioning System (APS).

Methods.Data were obtained in 463 patients treated with the B model and 518 patients treated with the C model. Data were analyzed in patients in whom the following diagnoses had been made: vestibular schwannoma, pituitary adenoma, meningioma, solitary metastasis, and other benign and malignant solitary tumors. Patients with arteriovenous malformations, ocular lesions, and functional diagnoses were excluded from this study.

Conclusions.With the C model there was a better conformity for most treated targets, such as vestibular schwannomas (p = 0.005) and meningiomas (p = 0.015). The level of radiation exposures to personnel was significantly decreased when using the model C (p < 0.001). There was no significant difference in radiation exposure of extracranial structures for the same number of shots in patients treated by both models. The mean time saved using the C model with the APS was 41 minutes per treatment. It would seem that the gamma knife model C permits better dose conformity, shorter treatment times, and less radiation exposure to personnel.
Treatment of essential trigeminal neuralgia with gamma knife surgery
Authors: Urgosik Dusan , Liscak Roman , Novotny Josef , Vymazal Josef , Vladyka Vilibald
Published: May 2009

Object.The authors present the long-term follow-up results (minimum 5 years) of patients with essential trigeminal neuralgia (TN) who were treated with gamma knife surgery (GKS).

Methods.One hundred seven patients (61 females and 46 males) underwent GKS. The median follow up was time was 60 months (range 12–96 months). The target was the trigeminal root, and the maximum dose was 70 to 80 Gy. Repeated GKS was performed in 19 patients for recurrent pain, and the same dose was used.

Initial successful results were achieved in 96% of patients, with complete pain relief in 80.4%. Relief was achieved after a median latency of 3 months (range 1 day–13 months). Gamma knife surgery failed in 4% of patients. Pain recurred in 25% of patients after a median latent interval of 36 months (6–94 months). The initial success rate after a second GKS was 89% and 58% of patients were pain free. Pain relapse occurred in only one patient in this group. Hypesthesia was observed in 20% of patients after the first GKS and in 32% after the second GKS. The median interval to hypaesthesia was 35 months (range 3–94 months) after one treatment and 21 months (range 1–72 months) after a second treatment.

Conclusions.The initial success rate of pain relief was high and comparable to that reported in other studies. A higher than usual incidence of sensory impairment after GKS could be the long duration of follow-up study and due to the detailed neurological examination.
The effect of gamma knife irradiation on functions of striatum in rats
Authors: Tokumaru Osamu , Tomida Mihoko , Katayama Yoko , Hayashi Mootohiro , Kawakami Yoriko , Kouyama Nobuo
Published: May 2009

Object.An animal model has been developed to study the effect of gamma knife surgery(GKS) on cerebral function.

Methods.A rat was fixed in a newly developed Régis—Valliccioni frame that enables the target region to be planned directly on the magnetic resonance images. The left striatum was irradiated with 150 Gy via a 4-mm collimator of the Leksell gamma knife. Apomorphine (dopamine agonist) was administered to elicit a circling behavior (apomorphine test) after the GKS so as to examine the time course of the changes in dopaminergic functions of irradiated striatum. After a series of behavioral analyses, irradiated brains were subjected to histological examination.

Necrosis was observed in the irradiated area surrounded by hemorrhage and gliosis. The distance between the histologically estimated and planned centers of the irradiation areas was 1.0 ± 0.5 mm. The extent of the distance was due to errors along dorsoventral axis. The distribution of the irradiation areas influenced the activity and the circling behaviors in apomorphine test, which was suggestive of involvement of the nigrostriatal pathway.

Conclusions.Targeting by using the Régis—Valliccioni frame was very accurate compared with targeting with coordinates based on brain maps used hitherto. Although targeting improved the accuracy, further effort will still be necessary to reduce errors along dorsoventral axis. The apomorphine test indicated a reduced dopaminergic function of the irradiated area including striatum, which accompanied histological changes after a high dose of irradiation (150 Gy).
Gamma knife surgery for arteriovenous malformations involving the corpus callosum
Authors: Maruyama Keisuke , Shin Masahiro , Tago Masao , Kurita Hiroki , Kawamoto Shunsuke , Morita Akio , Kirino Takaaki
Published: May 2009

Object. The purpose of this study was to evaluate the safety and efficacy of gamma knife surgery (GKS) for the treatment of arteriovenous malformations (AVMs) involving the corpus callosum.

Methods. Thirty-two patients aged from 7 to 65 years (median 25 years) with AVMs of the corpus callosum underwent GKS between 1990 and 2002. The maximum AVM diameter was more than 3 cm in 11 patients (34%). The AVM volume ranged from 0.1 to 19.1 cm3 (median 1.6 cm3). The median dose to the AVM margin was 20 Gy (range 17–28 Gy). Patients were followed for 1 to 12 years (median 9 years). The angiographically confirmed actuarial obliteration rate was 64% and 74% at 4 and 6 years, respectively. Younger patient age (p < 0.05) and lower radiosurgery-based grading score (calculated from the patient age and AVM volume; p < 0.01) were the significant factors affecting successful AVM obliteration. No patient suffered a hemorrhage after GKS, although 28 patients (88%) had a history of hemorrhage from their AVMs. Radiation-induced neurological deficit was observed only in one patient (3%) who had undergone previous radiotherapy (50 Gy). No patient experienced complications of occlusion or stenosis of the normal vascular structures adjacent to the AVM.

Conclusions. Gamma knife surgery is a safe and effective treatment for selected patients with AVMs involving the corpus callosum, and it carries a low risk of damaging adjacent critical vascular structures. Even ruptured AVMs with relatively large diameter can be successfully treated, especially in younger patients, with minimal morbidity and a low risk of repeated hemorrhage.
Histopathological findings in a surgically resected thalamic cavernous hemangioma 1 year after 40-Gy irradiation
Authors: Nyáry István , Major Otto , Hanzély Zoltán , Szeifert György T.
Published: May 2009

✓ Stereotactic radiosurgery is a controversial treatment modality in the management of cerebral cavernous hemangiomas (CHs), and results vary from center to center. Even the interpretation of treatment failure is controversial. It is suggested that the systematic pathological investigation of irradiated specimens could help to resolve the controversy.

A hemorrhagic lesion in the posterior part of the thalamus had been diagnosed as a tumor and was treated with 40-Gy fractionated radiotherapy. One year after this treatment the case was reconsidered based on new imaging evidence, and the lesion was removed by conventional craniotomy. Histopathological examination revealed a CH with postirradiation changes. Compared with nonirradiated control CH tissue samples, there was endothelial cell destruction and marked fibrosis with scar tissue formation in the stroma of the treated lesion.

The histopathological findings in this specimen were similar to those described in arteriovenous malformations after gamma knife surgery. The results of light microscopic investigations suggest that the ionizing effect of radiation energy evokes vascular and connective tissue stroma changes in CHs as well.
Analysis of long-term outcomes and prognostic factors in patients with non—small cell lung cancer brain metastases treated by gamma knife radiosurgery
Authors: Gerosa Massimo , Nicolato Antonio , Foroni Roberto , Tomazzoli Laura , Bricolo Albino
Published: May 2009

Object.The authors conducted a study to evaluate the long-term outcomes and prognostic factors for survival in a large series of patients treated by gamma knife surgery (GKS) for non—small cell lung cancer (NSCLC) brain metastases.

Methods.The study is based on the retrospective analysis of clinical and radiological records obtained during a 10-year period (1993–2003), concerning 836 lesions in 504 patients. The lesions were primary in 86% and recurrent 14% of the cases; they were solitary in 31%, single in 29%, and multiple in 40%. The mean follow-up period was 16 months (range 4–113 months). The most common histological types were adenocarcinoma (51%) and squamous cell carcinoma (27%). Dose planning parameters were as follows: mean target volume 6.2 cm3(range 0.06–22.5 cm3); mean prescription dose 21.4 Gy (range 15.5–28 Gy); and mean number of isocenters 6.7 (range one–18). Progression-free and actuarial survival curves were calculated using the Kaplan—Meier method. The main factors affecting survival were determined by unimultivariate analysis (log-rank test and Cox proportional hazard models).

Analysis of long-term outcomes seemed to confirm that GKS is a primary therapeutic option in these patients. The 1-year local tumor control rate was 94%. The overall median survival was 14.5 months, with extremely rewarding quality of life indices. The recursive partitioning analysis classification was the dominant prognostic factor.

Conclusions.Gamma knife surgery is a useful treatment for brain metastases from NSCLC.
Gamma knife surgery for cavernous hemangiomas: an analysis of 125 patients
Authors: Liu Kang-Du , Chung Wen-Yuh , Wu Hsiu-Mei , Shiau Cheng-Ying , Wang Ling-Wei , Guo Wan-You , Hung-Chi Pan David
Published: May 2009

Object. The authors sought to determine the value of gamma knife surgery (GKS) in the treatment of cavernous hemangiomas (CHs).

Methods. Between 1993 and 2002, a total of 125 patients with symptomatic CHs were treated with GKS. Ninety-seven patients presented with bleeding and 45 of these had at least two bleeding episodes. Thirteen patients presented with seizures combined with hemorrhage, and 15 patients presented with seizures alone. The mean margin dose of radiation was 12.1 Gy and the mean follow-up time was 5.4 years.

In the 112 patients who had bled the number of rebleeds after GKS was 32. These rebleeds were defined both clinically and based on magnetic resonance imaging for an annual rebleeding rate of 32 episodes/492 patient-years or 6.5%. Twenty-three of the 32 rebleeding episodes occurred within 2 years after GKS. Nine episodes occurred after 2 years; thus, the annual rebleeding rate after GKS was 10.3% for the first 2 years and 3.3% thereafter (p = 0.0038). In the 45 patients with at least two bleeding episodes before GKS, the rebleeding rate dropped from 29.2% (55 episodes/188 patient-years) before treatment to 5% (10 episodes/197 patient-years) after treatment (p < 0.0001). Among the 28 patients who presented with seizures, 15 (53%) had good outcomes (Engel Grades I and II). In this study of 125 patients, symptomatic radiation-induced complications developed in only three patients.

Conclusions. Gamma knife surgery can effectively reduce the rebleeding rate after the first symptomatic hemorrhage in patients with CH. In addition, GKS may be useful in reducing the severity of seizures in patients with CH.
Gamma knife surgery for multiple hemangioblastomas
Authors: Park Yong Sook , Chang Jong Hee , Chang Jin Woo , Chung Sang Sup , Park Yong Gou
Published: May 2009

Object. The authors describe their experience in treating patients with hemangioblastoma, especially multiple lesions, with gamma knife surgery (GKS).

Methods.Nine patients with 84 hemangioblastomas underwent GKS between July 1992 and May 2003. Three patients harbored a single lesion and six patients had multiple lesions. Of the six patients with multifocal tumors, a diagnosis of von Hippel—Lindau disease had been established in five. In the patients with multiple lesions, the mean radiation dose delivered to the tumor margin was 16.6 Gy (range 12.8–29.75 Gy). The mean margin isodose was 60% (range 40–95%).

Three of the 84 lesions failed to be controlled after a mean follow-up period of 4.3 years (range 8.6–141 months). One patient who had undergone two GKS treatments suffered delayed radiation-induced complications, and posterior fossa decompression and ventriculoperitoneal shunt insertion were required.

Conclusions. To achieve tumor control and avoid morbidity, the surgeon should keep in mind minimizing field overlapping by using a small-diameter collimator or applying a steep dose gradient, and by accurate dose prescription.
Cyst formation following gamma knife surgery for intracranial meningioma
Authors: Shuto Takashi , Inomori Shigeo , Fujino Hideyo , Nagano Hisato , Hasegawa Naoki , Kakuta Yukio
Published: May 2009

Object.The authors conducted a study to evaluate the clinical significance of cyst formation or enlargement after gamma knife surgery (GKS) for intracranial benign meningiomas.

Methods.The medical records of 160 patients with 184 tumors were examined for those with follow-up data of more than 2 years among 270 patients who underwent GKS for intracranial meningiomas between February 1992 and November 2001.

Cyst formation or enlargement following GKS was observed in five patients, one man and four women (mean age 61.2 years). The tumor location was the sphenoid ridge in one case, petroclival in two, tentorium in one, and parasagittal region in one. All patients underwent surgery before GKS. The mean tumor volume was 10.5 cm3, the mean margin dose was 13.4 Gy (median 14 Gy), and the mean maximum dose was 27.5 Gy (median 24.1 Gy). At the time of GKS three tumors were associated with cyst, of which two enlarged after radiosurgery. Three cysts developed de novo after GKS. Three of the five patients needed surgery to treat the cyst formation or enlargement. Histological examination demonstrated various findings such as tumor necrosis, proliferation of small vessels, vascular obliteration, and hemosiderin deposits.

Conclusions.New cyst formation following GKS for benign intracranial meningioma is relatively rare; however, both preexisting and newly developed cysts tend to enlarge after GKS and often require surgery.
Stereotactic noninvasive volume measurement compared with geometric measurement for indications and evaluation of gamma knife treatment
Authors: Del Valle Ramiro , Pérez Miguel , Ortiz Juan , Ruiz Salvador , de Anda Salvador , Jaramillo José , Martínez Manuel , Corona Roberto , Vivas Ingrid , Facha M.A. Teresa , Olmos Rosario , Arrieta Arturo , Estrada Josué
Published: May 2009

Object. Volume estimation is one of the most important criteria in the evaluation and follow up of radiosurgical treatments and outcomes; however, several limitations are involved in the calculation estimation of target volumes.

Methods. Retrospective and prospective studies were conducted to evaluate the efficacy of a new noninvasive stereotactic method when it is compared with geometric volume calculation of intracranial tumors for planning stereotactic radiosurgery treatment as well as for follow up and outcome evaluation.

Two equations were created that permit comparison of the calculated and measured volumes. These equations took linear and quadratic forms, respectively. Volume estimation using the stereotactic approach compared with traditional volume calculation gave more accurate results regardless of the shape and size of the lesion.

Conclusions. The use of stereotactic volume calculation is highly recommended in planning, follow up, and determination of the outcome in patients participating in radiosurgical treatment and should lead to more uniform reports of the response to treatment.
Evaluation of a new concept for the management of skull base chordomas and chondrosarcomas
Authors: Feigl Guenther Christian , Bundschuh Otto , Gharabaghi Alireza , Safavi-Abassi Sam , El Shawarby Amr , Samii Madjid , Horstmann Gerhard A.
Published: May 2009

Object. Chordomas and chondrosarcomas of the skull base are rare locally invasive tumors associated with high recurrence rates. The aim of this study was to evaluate the concept of microsurgical tumor volume reduction followed by early gamma knife surgery (GKS).

Methods. Thirteen patients with 15 tumors were treated between October 2000 and June 2003. There were three patients (23.1%) with chordomas and 10 (76.9%) with chondrosarcomas. There were nine men and four women who ranged in age between 19 and 69 years. All patients first underwent maximal tumor resection. Within 2 to 10 months after surgery they were treated with GKS. The mean postoperative tumor volume treated with GKS was 9.7 cm3 (range 1.4–20.3 cm3). Follow-up computerized tomography and magnetic resonance imaging examinations with volumetric tumor analysis were performed every 6 months after GKS.

The mean treatment dose was 17 Gy and the mean isodose was 52%. The mean follow-up duration was 17 months during which there was only one tumor recurrence at the margin of the radiation field. The mean volume reduction was 35.4%.

Conclusions. Results of this treatment strategy are encouraging but the efficacy of this multimodal treatment combining surgery and early GKS requires a longer follow up.
Gamma knife surgery for choroidal neovascularization in age-related macular degeneration
Authors: Hayashi Motohiro , Chernov Mikhail , Usukura Masao , Abe Kayoko , Ono Yuko , Izawa Masahiro , Hori Sadao , Hori Tomokatsu , Takakura Kintomo
Published: May 2009

The authors conducted a study to determine a way of overcoming the poor-quality demonstration of choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD) on conventional magnetic resonance (MR) imaging studies.

The poor MR imaging demonstration of CNV in patients with AMD makes the use of gamma knife surgery more difficult. This difficulty, however, can be overcome by use of a modified time-of-flight MR imaging sequence with Gd enhancement and coronal reconstruction.
Increased preservation of functional hearing after gamma knife surgery for vestibular schwannoma
Authors: van Eck Albertus T. C. J. , Horstmann Gerhard A.
Published: May 2009

Object.Gamma knife surgery (GKS) for vestibular schwannoma is still associated with an additional hearing loss of approximately 30%. The purpose of this study was to record the effect on hearing preservation of maintaining a margin dose of 13 Gy while reducing the maximum dose to 20 Gy.

Methods.Seventy-eight of 95 patients who entered a prospective protocol with a follow up of at least 12 months (mean 22 months) were evaluated. The mean tumor volume was 2.28 cm3. After a mean follow-up duration of 22 months, the magnetic resonance imaging—based tumor control rate was 87%. In two cases a second procedure (surgery) was necessary. Thus, the clinical control rate was 97.5%. In two cases there was an increase in trigeminal dysesthesia. One patient suffered transient facial nerve impairment. Functional hearing was preserved in 83.4% of the patients with functional hearing preoperatively.

Conclusions.Reducing the maximum dose to 20 Gy seems to be an effective treatment, which probably increases preservation of functional hearing without sacrificing the high tumor control rates achieved in radiosurgery. Post-radiosurgery tumor swelling occurred in 25% of the cases and was not correlated with hearing deterioration.