bluuebunny/crossref_metadata_2025 huggingface dataset:
Gamma knife surgery for trigeminal neuralgia: outcomes and prognostic factors
Authors: Sheehan Jason , Pan Hung-Chuan , Stroila Matei , Steiner Ladislau
Published: May 2009

Object. Microvascular decompression (MVD) and percutaneous ablation surgery have historically been the treatments of choice for medically refractory trigeminal neuralgia (TN). Gamma knife surgery (GKS) has been used as an alternative, minimally invasive treatment in TN. In the present study, the authors evaluated the long-term results of GKS in the treatment of TN.

Methods. From 1996 to 2003, 151 cases of TN were treated with GKS. In this group, radiosurgery was performed once in 136 patients, twice in 14 patients, and three times in one patient. The types of TN were as follows: 122 patients with typical TN, three with atypical TN, four with multiple sclerosis—associated TN, and seven with TN and a history of a cavernous sinus tumor. In each case, the chosen radiosurgical target was located 2 to 4 mm anterior to the entry of the trigeminal nerve into the pons. The maximal radiation doses ranged from 50 to 90 Gy. The median age of the patients was 68 years (range 22–90 years), and the median time from diagnosis to GKS was 72 months (range 1–276 months). The median follow up was 19 months (range 2–96 months). Clinical outcomes and postradiosurgical magnetic resonance (MR) imaging studies were analyzed. Univariate and multivariate analyses were performed to evaluate factors that correlated with a favorable, pain-free outcome.

The mean time to relief of pain was 24 days (range 1–180 days). Forty-seven, 45, and 34% of patients were pain free without medication at the 1-, 2-, and 3-year follow ups, respectively. Ninety, 77, and 70% of patients experienced some improvement in pain at the 1-, 2-, and 3-year follow ups, respectively. Thirty-three (27%) of 122 patients with initial improvement subsequently experienced pain recurrence a median of 12 months (range 2–34 months) post-GKS. Among those whose symptoms recurred, 14 patients underwent additional GKS, six MVD, four glycerol injection, and one patient a percutaneous radiofrequency rhizotomy. Twelve patients (9%) suffered the onset of new facial numbness post-GKS. Changes on MR images post-GKS were noted in nine patients (7%). On univariate analysis, right-sided neuralgia (p = 0.0002) and a previous neurectomy (p = 0.04) correlated with a pain-free outcome; on multivariate analysis, both right-sided neuralgia (p = 0.032) and patient age (p = 0.05) were statistically significant. New onset of facial numbness following GKS correlated with undergoing more than one GKS (p = 0.002).

Conclusions. At the last follow up, GKS effected pain relief in 44% of patients. Some degree of pain improvement at 3 years post-GKS was noted in 70% of patients with TN. Although less effective than MVD, GKS remains a reasonable treatment option for those unwilling or unable to undergo more invasive surgical approaches and offers a low risk of side effects.
Basilar artery dissection
Authors: Yoshimoto Yuhei , Hoya Katsumi , Tanaka Yoshihiro , Uchida Takanori
Published: May 2009

Object. Little is understood about the clinical manifestations of basilar artery (BA) dissections, which can present with subarachnoid hemorrhage (SAH), brainstem compression, or ischemia. In any instance, the prognosis seems poorer than that for vertebral artery (VA) dissection. The authors analyzed clinical presentations and radiological features of BA dissection with and without rupture.

Methods. Between 1998 and 2003, the authors treated 10 patients (eight men and two women, ranging in age from 32–78 years; mean age 54 years) with BA dissection. Diagnosis was based on clinical and radiological findings, including those from magnetic resonance imaging and cerebral angiography studies.

Of the 10 patients, five had impaired consciousness at disease onset. Among four patients presenting with SAH, two were treated conservatively and had fair outcomes without recurrent hemorrhage. The other two patients with SAH were treated using unilateral endovascular VA occlusion, but one of them subsequently suffered fatal rebleeding. A fifth patient presented with progressive signs of a mass involving the brainstem, whereas the remaining five patients showed brainstem ischemia; all were treated conservatively. Four patients could not return to their previous daily activities.

Conclusions. Basilar artery dissections are rare lesions associated with significant morbidity and death. The natural course of and the treatment options for BA dissection differ considerably from those for VA dissections. Management of these lesions is controversial and difficult, and requires particular care.
Multiple aneurysms of the anterior communicating artery: radiological and surgical difficulties
Authors: Inci Servet , Özgen Tuncalp
Published: May 2009

Object. Multiple aneurysms of the anterior communicating artery (ACoA) occur rarely and have not been well investigated previously. The authors report on a consecutive series of six patients who each harbored multiple ACoA aneurysms. The radiological and surgical difficulties encountered in treating these complex and uncommon aneurysms are described and the pertinent literature is reviewed.

Methods. Between October 1996 and August 2003, the authors surgically treated 146 patients with ACoA aneurysms. Six (4.1%) of these patients harbored multiple aneurysms of the ACoA. Four of these patients were men and two were women; their ages ranged from 36 to 72 years. Five patients had two aneurysms and one patient had three. All underwent surgery performed using the pterional approach. The clinical presentations, angiograms, intraoperative difficulties, and surgical results were retrospectively analyzed.

All patients had premorbid hypertension. In two cases, the aneurysms were initially misdiagnosed as a single complex aneurysm based on routine cerebral angiograms, but special angiographic views demonstrated double aneurysms. In one case, multiple ACoA aneurysms could be identified using three-dimensional (3D) computerized tomography (CT) angiography. The size of the ACoA aneurysms ranged from 3 to 12 mm (mean 5.3 mm). A total of 13 ACoA aneurysms were successfully occluded in the six patients. Four patients were discharged in good condition, and two patients died.

Conclusions. Although multiple ACoA aneurysms are quite rare, the following points should be kept in mind. 1) In bilobular ACoA aneurysms, special angiographic projections and 3D CT angiography or 3D digital subtraction angiography should also be performed to obtain a correct diagnosis. The differentiation of two aneurysms from a bilobular aneurysm during the preoperative period is important for surgical planning. 2) Angiographically, detection of the ruptured aneurysm is often difficult. 3) Resection of the gyrus rectus is necessary to obtain a good operative exposure. 4) Clip selection and sequencing are important. Straight clips with short blades should be preferred to avoid narrowing of the surgeon's view and a collision between the clips.
Responsiveness of life-threatening refractory emesis to gabapentin—scopolamine therapy following posterior fossa surgery
Authors: Guttuso Thomas , Vitticore Philip , Holloway Robert G.
Published: May 2009

✓ Craniotomy-associated chronic emesis can be refractory to currently approved antiemetic therapy. The authors describe a man who suffered 4 weeks of severe refractory emesis, failure to thrive, and a 40-lb weight loss after he underwent resection of a posterior fossa cholesteatoma. The patient experienced complete resolution of emesis and anorexia in response to combined gabapentin—scopolamine therapy. This case provides anecdotal evidence for the use of gabapentin—scopolamine therapy in patients with chronic, refractory nausea and emesis, particularly following posterior fossa surgery, during which medullary nausea and emesis centers may be affected.
Combined use of tractography-integrated functional neuronavigation and direct fiber stimulation
Authors: Kamada Kyousuke , Todo Tomoki , Masutani Yoshitaka , Aoki Shigeki , Ino Kenji , Takano Tetsuya , Kirino Takaaki , Kawahara Nobutaka , Morita Akio
Published: May 2009

Object. The aim of this study was better preoperative planning and direct application to intraoperative procedures through accurate coregistration of diffusion-tensor (DT) imaging—based tractography results and anatomical three-dimensional magnetic resonance images and subsequent importation of the combined images to a neuronavigation system (functional neuronavigation).

Methods. Six patients with brain lesions adjacent to the corticospinal tract (CST) were studied. During surgery, direct fiber stimulation was used to evoke motor responses to confirm the accuracy of CST depicted on functional neuronavigation. In three patients, stimulation of the supposed CST elicited the expected motor evoked potentials. In the other three, stimulation at the resection borders more than 1 cm away from the supposed CST showed no motor response. All patients underwent appropriate tumor resection with preservation of the CST.

Conclusions. Integration of the DT imaging—based tractography information into a traditional neuronavigation system demonstrated spatial relationships between lesions and the CST, allowing for the avoidance of tract injury during lesion resection. Direct fiber stimulation was used for real-time reliable white matter mapping, which served to adjust for any discrepancy between the neuronavigation system data and potentially shifted positions of the brain structures. The combination of these techniques enabled the authors to identify accurate positions of the CST during surgery and to accomplish optimal tumor resections.
Integration of three-dimensional corticospinal tractography into treatment planning for gamma knife surgery
Authors: Maruyama Keisuke , Kamada Kyousuke , Shin Masahiro , Itoh Daisuke , Aoki Shigeki , Masutani Yoshitaka , Tago Masao , Kirino Takaaki
Published: May 2009

Object. In the radiosurgical treatment of critically located lesions, the effort to minimize the risk of complication is essential. In this study the integration of diffusion-tensor (DT) imaging—based tractography was clinically applied to treatment planning for gamma knife surgery (GKS).

Methods. Seven patients with cerebral arteriovenous malformations located adjacent to the corticospinal tract (CST) underwent this technique. Data provided by DT imaging were acquired before the frame was affixed to the patient's head and the CST of the DT tractography was created using our original software. Stereotactic three-dimensional imaging studies were obtained after frame fixation and then coregistered with the data from DT tractography. After image fusion of the two studies, the combined images were transported to a GKS treatment-planning workstation. The spatial relationship between the dose distribution and the CST was clearly demonstrated within the 2 hours it took to complete the entire imaging process. The univariate logistic regression analysis of transient or permanent motor complications revealed a significant independent correlation with the volume of the CST that received 25 Gy or more and with a maximum dose to the CST (p < 0.05).

Conclusions. The integration of DT tractography into the GKS treatment planning was highly useful in confirming the dose to the CST during treatment planning.
Intraoperative control of extracranial—intracranial bypass patency by near-infrared indocyanine green videoangiography
Authors: Woitzik Johannes , Horn Peter , Vajkoczy Peter , Schmiedek Peter
Published: May 2009

Object. Recently, intraoperative fluorescence angiography in which indocyanine green (ICG) is used as a tracer has been introduced as a novel technique to confirm successful aneurysm clipping. The aim of the present study was to assess whether ICG videoangiography is also suitable for intraoperative confirmation of extracranial—intracranial bypass patency.

Methods. Forty patients undergoing cerebral revascularization for hemodynamic cerebral ischemia (11 patients), moyamoya disease (18 patients), or complex intracranial aneurysms (11 patients) were included. Superficial temporal artery (STA)—middle cerebral artery (MCA) bypass surgery was performed 35 times in 30 patients (five patients with moyamoya underwent bilateral procedures), STA—posterior cerebral artery bypass surgery in two patients, and saphenous vein (SV) high-flow bypass surgery in eight patients. In each patient, following the completion of the anastomosis, ICG (0.3 mg/kg body weight) was given systemically via an intravenous bolus injection. A near-infrared light emitted by laser diodes was used to illuminate the operating field and the intravascular fluorescence was recorded using an optical filter—equipped video camera. The findings of ICG videoangiography were compared with those of postoperative digital subtraction (DS) or computerized tomography (CT) angiography.

In all cases excellent visualization of cerebral arteries, the bypass graft, and brain perfusion was noted. Indocyanine green videoangiography was used to identify four nonfunctioning STA—MCA bypasses, which could be revised successfully in all cases. In two cases of SV high-flow bypasses, ICG videoangiography revealed stenosis at the proximal anastomotic site, which was also revised successfully. In all cases the final findings of ICG videoangiography could be positively validated during the postoperative course by performing DS or CT angiography.

Conclusions. Indocyanine green videoangiography provides a reliable and rapid intraoperative assessment of bypass patency. Thus, ICG videoangiography may help reduce the incidence of early bypass graft failure.
Functional and phenotypic differences between glioblastoma multiforme—derived and normal human brain endothelial cells
Authors: Charalambous Christiana , Hofman Florence M. , Chen Thomas C.
Published: May 2009

Object. Glioblastomas multiforme (GBMs) are hypervascular tumors characterized by endothelial cell (EC) proliferation. There is increasing evidence that ECs that infiltrate systemic tumors are different from normal blood vessel cells; whether this difference is seen in the central nervous system between GBM and normal brain tissue is not known. The goal of this investigation was to characterize and compare the functional and phenotypic properties of GBM-associated ECs and normal brain ECs.

Methods. Human ECs were isolated from fresh tissue specimens, purified using flow cytometry, and characterized by immunostaining. Proliferation was measured by determining bromodeoxyuridine incorporation and Ki-67 staining, and by performing the monotetrazolium assay. The migration rate of the cells was determined using the modified Boyden chamber technique. Apoptosis was evaluated by performing the TUNEL assay, cell death enzyme-linked immunosorbent assay (ELISA), and annexin V staining. Growth factor production was analyzed using the ELISA technique.

The brain tumor ECs differed from normal brain ECs morphologically and by their expression and distribution of specific markers (that is, vascular endothelial cadherin [VE-cadherin] and CD31). Functional differences between the two cell populations were also evident. The brain tumor ECs proliferated more slowly and underwent less apoptosis than normal brain ECs; however, the tumor ECs migrated faster than the normal ECs. The normal ECs were sensitive to growth factors such as vascular endothelial growth factor (VEGF) and endothelin-1 (ET-1), whereas the tumor ECs were not. In addition, the brain tumor ECs constitutively produced higher levels of ET-1 and VEGF, compared with the normal ECs.

Conclusions. The data demonstrated that ECs derived from normal brain and from GBMs have significant phenotypic and functional distinctions. Further characterization of brain tumor ECs is essential for efficient antiangiogenic treatment of gliomas.
Risk of hemorrhage from an arteriovenous malformation confirmed to have been obliterated on angiography after stereotactic radiosurgery
Authors: Shin Masahiro , Kawahara Nobutaka , Maruyama Keisuke , Tago Masao , Ueki Keisuke , Kirino Takaaki
Published: May 2009

Object. Radiosurgery has been widely adopted for the treatment of cerebral arteriovenous malformations (AVMs) in which the practical endpoint is angiographic evidence of obliteration, presumed to be consistent with elimination of the risk of hemorrhage. To test this unverified assumption, the authors followed 236 radiosurgery-treated AVMs between 1 and 133 months (median 77 months) after angiographic evidence of obliteration.

Methods. Four patients experienced hemorrhage between 16 and 51 months after angiographic confirmation of AVM obliteration, and two underwent resection. The histological findings in these patients showed occlusion of the AVM by thickening of the intimal layer with dense hyalinization as well as a small amount of residual AVM vessels and a tiny vasculature. The risks of hemorrhage from these presumaby obliterated AVMs were 0.3% for the annual bleeding risk and 2.2% for the cumulative risk over 10 years. Continuous enhancement of the nidus on computerized tomography (CT) or magnetic resonance (MR) imaging was the only significant factor positively associated with hemorrhage in the statistical analysis (p = 0.0212).

Conclusions. Because the study was based on limited follow-up data, its significance for defining predictive features of hemorrhage after angiographic evidence of obliteration is still indeterminable. Nevertheless, disappearance of the AVM on angiography after radiosurgery does not always indicate total elimination of the disease, especially when CT or MR imaging continues to demonstrate an enhancing lesion. The authors therefore recommend continual follow up even after evidence of AVM obliteration on angiography.
Sex differences in outcome following sports-related concussion
Authors: Broshek Donna K. , Kaushik Tanya , Freeman Jason R. , Erlanger David , Webbe Frank , Barth Jeffrey T.
Published: May 2009

Object. Females comprise an increasing percentage of the athlete population across all age groups, and analysis of recent literature reveals that they sustain more concussions in collegiate sports. Results of human and animal studies indicate that females may have poorer outcomes after traumatic brain injury; however, no return-to-play guideline takes sex or other individual differences into account. In the present study the authors evaluated the influence of patient sex on objective neurocognitive performance and subjective reporting of symptoms following sports-related concussion.

Methods. According to preseason baseline neurocognitive computerized testing in 2340 male and female high school and collegiate athletes, individuals who sustained sports-related concussions (155 persons) were reevaluated using an alternate form of the cognitive test. Sex differences in the magnitude of cognitive change from baseline levels and the subjective experience of symptoms were analyzed. To account for the possible protective effects of helmets, comparisons were performed among females, males with helmets, and males without helmets; none of the female athletes wore helmets.

Female athletes had significantly greater declines in simple and complex reaction times relative to preseason baseline levels, and they reported more postconcussion symptoms compared with males. As a group, females were cognitively impaired approximately 1.7 times more frequently than males following concussions. Furthermore, females experienced more objective and subjective adverse effects from concussion even after adjusting for the use of helmets by some groups of male athletes (for example, in football).

Conclusions. Return-to-play decisions and concussion management must be objective and made on an individual basis, including consideration of factors such as patient sex rather than relying on a one-size-fits-all guideline.
Independent predictors of morbidity after image-guided stereotactic brain biopsy: a risk assessment of 270 cases
Authors: McGirt Matthew J. , Woodworth Graeme F. , Coon Alex L. , Frazier James M. , Amundson Eric , Garonzik Ira , Olivi Alessandro , Weingart Jon D.
Published: May 2009

Object. Image-guided stereotactic brain biopsy is associated with transient and permanent incidences of morbidity in 9 and 4.5% of patients, respectively. The goal of this study was to perform a critical analysis of risk factors predictive of an enhanced operative risk in frame-based and frameless stereotactic brain biopsy.

Methods. The authors reviewed the clinical and neuroimaging records of 270 patients who underwent consecutive frame-based and frameless image-guided stereotactic brain biopsies. The association between preoperative variables and biopsy-related morbidity was assessed by performing a multivariate logistic regression analysis.

Transient and permanent stereotactic biopsy-related morbidity was observed in 23 (9%) and 13 (5%) patients, respectively. A hematoma occurred at the biopsy site in 25 patients (9%); 10 patients (4%) were symptomatic. Diabetes mellitus (odds ratio [OR] 3.73, 95% confidence interval [CI] 1.37–10.17, p = 0.01), thalamic lesions (OR 4.06, 95% CI 1.63–10.11, p = 0.002), and basal ganglia lesions (OR 3.29, 95% CI 1.05–10.25, p = 0.04) were independent risk factors for morbidity. In diabetic patients, a serum level of glucose that was greater than 200 mg/dl on the day of biopsy had a 100% positive predictive value and a glucose level lower than 200 mg/dl on the same day had a 95% negative predictive value for biopsy-related morbidity. Pontine biopsy was not a risk factor for morbidity. Only two (4%) of 45 patients who had epilepsy before the biopsy experienced seizures postoperatively. The creation of more than one needle trajectory increased the incidence of neurological deficits from 17 to 44% when associated with the treatment of deep lesions (those in the basal ganglia or thalamus; p = 0.05), but was not associated with morbidity when associated with the treatment of cortex lesions.

Conclusions. Basal ganglia lesions, thalamic lesions, and patients with diabetes were independent risk factors for biopsy-associated morbidity. Hyperglycemia on the day of biopsy predicted morbidity in the diabetic population. Epilepsy did not predispose to biopsy-associated seizure. For deep-seated lesions, increasing the number of biopsy samples along an established track rather than performing a second trajectory may minimize the incidence of morbidity. Close perioperative observation of glucose levels may be warranted.
Supraorbital craniotomy for parasellar lesions
Authors: Noguchi Akio , Balasingam Vijayabalan , McMenomey Sean O. , Delashaw Johnny B.
Published: May 2009

✓ The authors present a modification to a previously reported supraorbital craniotomy procedure that is smaller, simpler, safe, and cosmetically pleasing. Minimal brain retraction is used without compromising the surgical exposure of the orbital roof, floor of the anterior fossa, and the parasellar region to treat tumoral lesions that are located medial to the ipsilateral optic nerve as well as aneurysms of the anterior communicating artery.
Diagnosis and management of idiopathic normal-pressure hydrocephalus: a prospective study in 151 patients
Authors: Marmarou Anthony , Young Harold F. , Aygok Gunes A. , Sawauchi Satoshi , Tsuji Osamu , Yamamoto Takuji , Dunbar Jana
Published: May 2009

Object. The diagnosis and management of idiopathic normal-pressure hydrocephalus (NPH) remains controversial, particularly in selecting patients for shunt insertion. The use of clinical criteria coupled with imaging studies has limited effectiveness in predicting shunt success. The goal of this prospective study was to assess the usefulness of clinical criteria together with brain imaging studies, resistance testing, and external lumbar drainage (ELD) of cerebrospinal fluid (CSF) in determining which patients would most likely benefit from shunt surgery.

Methods. One hundred fifty-one patients considered at risk for idiopathic NPH were prospectively studied according to a fixed management protocol. The clinical criterion for idiopathic NPH included ventriculomegaly demonstrated on computerized tomography or magnetic resonance imaging studies combined with gait disturbance, incontinence, and dementia. Subsequently, all patients with a clinical diagnosis of idiopathic NPH underwent a lumbar tap for the measurement of CSF resistance. Following this procedure, patients were admitted to the hospital neurosurgical service for a 3-day ELD of CSF. Video assessment of gait and neuropsychological testing was conducted before and after drainage. A shunt procedure was then offered to patients who had experienced clinical improvement from ELD. Shunt outcome was assessed at 1 year postsurgery.

Conclusions. Data in this report affirm that gait improvement immediately following ELD is the best prognostic indicator of a positive shunt outcome, with an accuracy of prediction greater than 90%. Furthermore, bolus resistance testing is useful as a prognostic tool, does not require hospitalization, can be performed in an outpatient setting, and has an overall accuracy of 72% in predicting successful ELD outcome. Equally important is the finding that improvement with shunt surgery is independent of age up to the ninth decade of life in patients who improved on ELD.
Moyamoya disease associated with Graves disease: special considerations regarding clinical significance and management
Authors: Im So-Hyang , Oh Chang Wan , Kwon O-Ki , Kim Jung Eun , Han Dae Hee
Published: May 2009

Object. In moyamoya disease (MMD), ischemic events are usually precipitated by activities associated with hyperventilation or physical strain. The authors report on four patients with a rare combination of Graves disease—associated thyrotoxicosis and MMD, whose cerebrovascular ischemic events occurred while in a thyrotoxic state. The clinical correlation between MMD and Graves' thyrotoxicosis, and outcome after surgical intervention are described.

Methods. Four young women, ages 22 to 25 years, presented with profound cerebrovascular ischemic accidents. They had clinical and radiological features consistent with the diagnosis of MMD and were in the active thyrotoxic state of Graves disease. To prevent a future ischemic event, patients underwent superficial temporal artery—middle cerebral artery anastomosis combined with encephalomyosynangiosis or encephaloduroarteriosynangiosis after normalization of their hormonal conditions. All patients have been neurologically stable since revascularization procedures and lead a normal daily life.

In patients with MMD, cerebrovascular ischemic events may be precipitated by thyrotoxicosis. One possible pathomechanism of cerebrovascular ischemic aggravation in the thyrotoxic state may be a hemodynamic compromise induced by an excessive increase in the cerebral metabolism and oxygen demand over the compensation of the cerebral blood flow deficit through collateral supply in MMD.

Conclusions. Surgical revascularization after optimal control of thyrotoxicosis is thought to be an appropriate treatment in patients with MMD concurrent with Graves disease for the prevention of further ischemic events, especially in those with impaired cerebral perfusion and cerebral ischemic symptoms.
Induction of reactive oxygen intermediates—dependent programmed cell death in human malignant ex vivo glioma cells and inhibition of the vascular endothelial growth factor production by taurolidine
Authors: Rodak Roksana , Kubota Hisashi , Ishihara Hideyuki , Eugster Hans-Pietro , Könü Dilek , Möhler Hanns , Yonekawa Yasuhiro , Frei Karl
Published: May 2009

Object. Taurolidine, a derivative of the amino acid taurin, was recently found to display a potent antineoplastic effect both in vitro and in vivo. The authors therefore initiated studies to assess the potential antineoplastic activity of taurolidine in human glioma cell lines and in ex vivo malignant cell cultures. They also studied the mechanisms that induce cell death and the impact of taurolidine on tumor-derived vascular endothelial growth factor (VEGF) production.

Methods. Cytotoxicity and clonogenic assays were performed using crystal violet staining. In the cytotoxicity assay 100% of glioma cell lines (eight of eight) and 74% of ex vivo glioma cultures (14 of 19) demonstrated sensitivity to taurolidine, with a mean median effective concentration (EC50) of 51 ± 28 µg/ml and 56 ± 23 µg/ml, respectively. Colony formation was inhibited by taurolidine, with a mean EC50 of 7 ± 3 µg/ml for the cell lines and a mean EC50 of 3.5 ± 1.7 µg/ml for the ex vivo glioma cultures. On observing this high activity of taurolidine in both assays, the authors decided to evaluate its cell death mechanisms.

Fragmentation of DNA, externalization of phosphatidylserine, activation of poly(adenosine diphosphate—ribose) polymerase, loss of the mitochondrial membrane potential followed by a release of apoptosis-inducing factor, and typical apoptotic features were found after taurolidine treatment. Cell death was preceded by the generation of reactive O2 intermediates, which was abrogated by N-acetylcysteine but not by benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone. Moreover, taurolidine also induced suppression of VEGF production on the protein and messenger RNA level, as shown by an enzyme-linked immunosorbent assay and by reverse transcription—polymerase chain reaction.

Conclusions. Given all these findings, taurolidine may be a promising new agent in the treatment of malignant gliomas; it displays a combination of antineoplastic and antiangiogenic activities, inducing tumor cell apoptosis and inhibiting tumor-derived VEGF production.
Pressure gradients in the brain in an experimental model of hydrocephalus
Authors: Penn Richard D. , Lee Max C. , Linninger Andreas A. , Miesel Keith , Lu Steven Ning , Stylos Lee
Published: May 2009

Object. The goal of this investigation was to establish whether pressure gradients exist between the ventricles, brain tissue, and subarachnoid space when acute or chronic hydrocephalus develops. Such gradients are hypothesized by many models of hydrocephalus, but considerable controversy continues about their existence.

Methods. A stereotactic frame was used for surgery in dogs to implant pressure sensors within the right lateral ventricle, the frontal lobe, and forward in the subarachnoid space. The dogs were allowed to recover for 10 to 14 days postoperatively. Then, 800 mg of sterile kaolin in water was injected into the cisterna magna region by using a percutaneous approach. Both real-time and long-term intracranial pressures were measured.

Of the six dogs, one experienced an intracranial hemorrhage, one dog displayed status epilepticus after a second injection of kaolin and was killed, one experienced acute hydrocephalus, and three experienced mild chronic hydrocephalus. No consistent pressure differences were found in any dog between the ventricle, brain, and subarachnoid space before kaolin administration or afterward when hydrocephalus developed. In addition, no pulse pressure gradients occurred between the brain and the ventricle or subarachnoid space.

Conclusions. Precise monitoring of pressure before and during the development of hydrocephalus did not detect pressure gradients between the ventricle, brain, and subarachnoid space. This was true for long-term measurements over weeks and for real-time measurements that allowed accurate assessment of pulse pressures. Theories predicting pressure gradients greater than the resolution of these sensors (0.5 mm Hg) across brain tissue have to be reevaluated in light of these findings.
Zebra sign: cerebellar bleeding pattern characteristic of cerebrospinal fluid loss
Authors: Brockmann Marc A. , Nowak Georg , Reusche Erich , Russlies Martin , Petersen Dirk
Published: May 2009

✓ Supratentorial subdural hematoma is a well-known complication following spinal interventions. Less often, spinal or supratentorial interventions cause remote cerebellar hemorrhage (RCH). The exact pathomechanism accounting for RCH remains unclear, but an interventional or postinterventional loss of cerebrospinal fluid (CSF) seems to be involved in almost all cases. Hemorrhage is often characterized by a typical, streaky bleeding pattern due to blood spreading in the cerebellar sulci. Three different cases featuring this bleeding pattern following spinal, supratentorial, and thoracic surgery are presented. Possible pathomechanisms leading to RCH are discussed. Based on data from the underlying cases and the reviewed literature, the authors concluded that this zebra-pattern hemorrhage seems to be typical in a postoperative loss of CSF, which should always be considered on presentation of this bleeding pattern.
A simple method for predicting imaging-based complications following gamma knife surgery for cerebral arteriovenous malformations
Authors: Ganz Jeremy C. , Reda Wael A. , Abdelkarim Khalid , Hafez Ayman
Published: May 2009

Object.The authors studied the relationship between dose planning parameters and complications in the treatment of cerebral arteriovenous malformations (AVMs).

Methods.There were 41 continuous unselected patients. The mean follow-up period was 19 months; the mean age was 28 years; the male/female ratio was 2.2:1.0; the median prescription dose was 25 Gy (range 14–25 Gy); the median prescription isodose was 50%. The median lesion volume was 4.4 cm3. The median lesion coverage was 93%; and the mean conformity index was 1.22.

The authors found no relationship between lesion volume or integral dose and the development of the clinical effects based on the adverse radiation effects (AREs); however, there was a significant relationship between both target volume and integral dose with the development of AREs as well as the severity of the AREs.

Conclusions.The integral dose could be used as a guideline for the prescription dose. Arguments are made for maximizing the prescription dose for the long-term safety of the patient.
Long-term complications after gamma knife surgery for arteriovenous malformations
Authors: Izawa Masahiro , Hayashi Motohiro , Chernov Mikhail , Nakaya Koutarou , Ochiai Taku , Murata Noriko , Takasu Yuichi , Kubo Osami , Hori Tomokatsu , Takakura Kintomo
Published: May 2009

Object. The authors analyzed of the long-term complications that occur 2 or more years after gamma knife surgery (GKS) for intracranial arteriovenous malformations (AVMs).

Methods. Patients with previously untreated intracranial AVMs that were managed by GKS and followed for at least 2 years after treatment were selected for analysis (237 cases). Complete AVM obliteration was attained in 130 cases (54.9%), and incomplete obliteration in 107 cases (45.1%). Long-term complications were observed in 22 patients (9.3%). These complications included hemorrhage (eight cases), delayed cyst formation (eight cases), increase of seizure frequency (four cases), and middle cerebral artery stenosis and increased white matter signal intensity on T2-weighted magnetic resonance imaging (one case of each). The long-term complications were associated with larger nidus volume (p < 0.001) and a lobar location of the AVM (p < 0.01). Delayed hemorrhage was associated only with incomplete obliteration of the nidus (p < 0.05). Partial obliteration conveyed no benefit. Delayed cyst formation was associated with a higher maximal GKS dose (p < 0.001), larger nidus volume (p < 0.001), complete nidus obliteration (p < 0.01), and a lobar location of the AVM (p < 0.05).

Conclusions. Incomplete obliteration of the nidus is the most important factor associated with delayed hemorrhagic complications. Partial obliteration does not seem to reduce the risk of hemorrhage. Complete obliteration can be complicated by delayed cyst formation, especially if high maximal treatment doses have been administered.
Radiosurgery and the prevention of regrowth of incompletely removed nonfunctioning pituitary adenomas
Authors: Picozzi Piero , Losa Marco , Mortini Pietro , Valle Micol Angela , Franzin Alberto , Attuati Luca , da Passano Camillo Ferrari , Giovanelli Massimo
Published: May 2009

Object. The authors studied the efficacy of gamma knife radiosurgery (GKS) in the prevention of regrowth of nonfunctioning pituitary adenomas (NPA).

Methods. One hundred nineteen patients were included in this study and were divided into two groups. All patients had undergone surgery in our department and recurrent or residual adenoma was demonstrated on postoperative MR imaging. Group A consisted of 68 patients who were followed without additional treatment. Group B was composed of 51 patients who received GKS within 1 year after microsurgery. There was no significant demographic difference between the two groups. In Group B the mean margin dose was 16.5 ± 0.3 Gy (range 13–21 Gy). Fifty one and one tenth percent of patients in Group A were recurrence free at 5 years and 89.8% in Group B (p < 0.001). In Group B patients, tumor volume decreased from a baseline value of 2.4 ± 0.2 cm3 to 1.6 ± 0.2 cm3 at last follow up (p < 0.001).

Conclusions. The results of this study suggest that GKS is effective in controlling growth of residual NPA for at least 5 years following initial maximal surgical debulking compared with no radiation therapy. Thus, GKS is recommended after microsurgery when visible tumor can be detected on imaging studies.
Gamma knife surgery for intracranial cavernous hemangioma
Authors: Kim Moo Seong , Pyo Se Young , Jeong Young Gyun , Lee Sun Il , Jung Yong Tae , Sim Jae Hong
Published: May 2009

Object. The purpose of this study was to assess the benefits of radiosurgery for cavernous hemangioma.

Methods. Sixty-five cavernous hemangiomas were treated with gamma knife surgery (GKS) between October 1994 and December 2002. Forty-two patients attended follow up. The mean patient age was 37.6 years (range 7–60 years). The lesions were located in the frontal lobe in 12 cases, deep in the parietal lobe in five, in the basal ganglia in five, in the temporal in three, in the cerebellum in three, in the pons/midbrain in six, and in multiple locations in eight cases. The presenting symptoms were seizure in 12, hemorrhage in 11, and other in 19. The maximum dose was 26.78 Gy, and the mean margin dose was 14.55 Gy.

The mean follow-up period after radiosurgery was 29.6 months (range 5–93 months). The tumor decreased in size in 29 cases, was unchanged in 12, and increased in size in one. In the seizure group, seizures were controlled without anticonvulsant medication in nine cases (81.8%) after 31.3 months (range 12–80 months). After 93 months, one patient developed a cyst, which was resected. Rebleeding occurred in one case (2.3%). On T2-weighted imaging changes were seen in 11 cases (26.2%), in three (7.1%) of which neurological deterioration was correlated with imaging changes. In other cases these deficits were temporary.

Conclusions. The authors found that GKS was an effective treatment modality for cavernous hemangiomas, especially for those located within the brainstem, basal ganglia, or deep portions of the brain. It can reduce seizure frequency significantly although this takes time. In the group receiving a marginal dose below 15 Gy the patients fared better than when the dose exceeded 15 Gy.
Targeting the cranial nerve: microradiosurgery for trigeminal neuralgia with CISS and 3D-Flash MR imaging sequences
Authors: Zerris Vasilios A. , Noren Georg C. , Shucart William A. , Rogg Jeff , Friehs Gerhard M.
Published: May 2009

Object.The authors undertook a study to identify magnetic resonance (MR) imaging techniques that can be used reliably during gamma knife surgery (GKS) to identify the trigeminal nerve, surrounding vasculature, and areas of compression.

Methods.Preoperative visualization of the trigeminal nerve and surrounding vasculature as well as targeting the area of vascular compression may increase the effectiveness of GKS for trigeminal neuralgia. During the past years our gamma knife centers have researched different MR imaging sequences with regard to their ability to visualize cranial nerves and vascular structures. Constructive interference in steady-state (CISS) fusion imaging with three-dimensional gradient echo sequences (3D-Flash) was found to be of greatest value in the authors' 25 most recent patients.

In 24 (96%) out of the 25 patients, the fifth cranial nerve, surrounding vessels, and areas of compression could be reliably identified using CISS/3D-Flash. The MR images were acceptable despite patients' history of microvascular decompression, radiofrequency (RF) ablation, or concomitant disease. In one of 25 patients with a history of multiple RF lesions, the visualization was inadequate due to severe trigeminal nerve atrophy.

Conclusions.The CISS/3D-Flash fusion imaging has become the preferred imaging method at the authors' institutions during GKS for trigeminal neuralgia. It affords the best visualization of the trigeminal nerve, surrounding vasculature, and the precise location of vascular compression.
Outpatient gamma knife surgery for vestibular schwannoma: definition of the therapeutic profile based on a 10-year experience
Authors: Wowra Berndt , Muacevic Alexander , Jess-Hempen Anja , Hempel John-Martin , Müller-Schunk Stefanie , Tonn Jörg-Christian
Published: May 2009

Object.The purpose of the study was to define the therapeutic profile of outpatient gamma knife surgery (GKS) for vestibular schwannoma (VS) by using sequential tumor volumetry to quantify changes following treatment.

Methods.A total of 111 patients met the inclusion criteria. The median follow-up duration was 7 years (range 5–9.6 years). Thirty-seven patients (33%) had undergone surgery before GKS and 10 (9%) had neurofibromatosis Type 2 (NF2). The median VS volume was 1.6 cm3(range 0.08–8.7 cm3).

The actuarial 6-year tumor control rate after a single GKS treatment was 95%. Tumor swelling was observed in 43 patients (38.7%). Recurrence was significantly associated with NF2 (p < 0.003) and the reduced dose (p < 0.03) delivered to these tumors. The incidence of facial nerve neuropathy was mainly determined by surgery prior to GKS (p < 0.0001). Facial nerve radiation toxicity was mild and transient. No permanent facial nerve toxicity was observed. Trigeminal neuropathy occurred in 13 patients, and this was correlated with the VS volume (p < 0.02). The median hearing loss was −10 dB (range + 20 dB to −70 dB). The risk of hearing loss was correlated with age and transient tumor swelling (p < 0.05) but not with dose parameters or NF2.

Conclusions.Outpatient GKS is feasible, effective, and safe. Its therapeutic profile compares favorably with that of microsurgery.
Glossopharyngeal neuralgia treated with gamma knife surgery: treatment outcome and failure analysis
Authors: Stieber Volker W. , Bourland J. Daniel , Ellis Thomas L.
Published: May 2009

✓ Glossopharyngeal neuralgia (GPN) is a rare condition in which patients present with intractable deep throat pain. Similar to trigeminal neuralgia (TN), treatment with microvascular decompression (MVD) has been successful in both. Because gamma knife surgery (GKS) has also been shown to be effective in treating TN, it seemed reasonable to apply it to GPN. The authors present the first report of GKS-treated GPN in a patient who presented with severe, poorly controlled GPN and who refused MVD.
Analyzing 3-tesla magnetic resonance imaging units for implementation in radiosurgery
Authors: Mack Andreas , Wolff Robert , Scheib Stefan , Rieker Marcus , Weltz Dirk , Mack G. , Kreiner Hans-Jürg , Pilatus Ulrich , Zanella Friedhelm E. , Böttcher Heinz D. , Seifert Volker
Published: May 2009

Object.The limiting factor affecting accuracy during gamma knife surgery is image quality. The new generation of magnetic resonance (MR) imaging units with field strength up to 3 teslas promise superior image quality for anatomical resolution and contrast. There are, however, questions about chemical shifts or susceptibility effects, which are the subject of this paper.

Methods.The 3-tesla MR imaging unit (Siemens Trio) was analyzed and compared with a 1-tesla unit (Siemens Magnetom Expert) and to a 1.5-tesla unit (Philips Gyroscan). Evaluation of the magnitude of error was performed within transverse slices in two orientations (axial/coronal) by using a cylindrical phantom with an embedded grid. Deviations were determined for 21 targets in a slab phantom with known geometrical positions within the stereotactic frame. Distortions caused by chemical shift and/or susceptibility effects were analyzed in a head phantom. Inhouse software was used for data analyses.

The mean deviation was less than 0.3 mm in axial and less than 0.4 mm in coronal orientations. For the known targets the maximum deviation was 1.16 mm. By optimizing these parameters in the protocol these inaccuracies could be reduced to less than 1.1 mm. Due to inhomogeneities a shift in the z direction of up to 1.5 mm was observed for a dataset, which was shown to be compressed by 1.2 mm.

Conclusions.The 3-tesla imaging unit showed superior anatomical contrast and resolution in comparison with the established 1-tesla and 1.5-tesla units; however, due to the high field strength the field within the head coil is very sensitive to inhomogeneities and therefore 3-tesla imaging data will have be handled with care.
Does gamma knife surgery stimulate cellular immune response to metastatic brain tumors? A histopathological and immunohistochemical study
Authors: Szeifert György T. , Salmon Isabelle , Rorive Sandrine , Massager Nicolas , Devriendt Daniel , Simon Stephan , Brotchi Jacques , Levivier Marc
Published: May 2009

Object.The aim of this study was to analyze the cellular immune response and histopathological changes in secondary brain tumors after gamma knife surgery (GKS).

Methods.Two hundred ten patients with cerebral metastases underwent GKS. Seven patients underwent subsequent craniotomy for tumor removal between 1 and 33 months after GKS. Four of these patients had one tumor, two patients had two tumors, and one patient had three. Histological and immunohistochemical investigations were performed. In addition to routine H & E and Mallory trichrome staining, immunohistochemical reactions were conducted to characterize the phenotypic nature of the cell population contributing to the tissue immune response to neoplastic deposits after radiosurgery.

Light microscopy revealed an intensive lymphocytic infiltration in the parenchyma and stroma of tumor samples obtained in patients in whom surgery was performed over 6 months after GKS. Contrary to this, extensive areas of tissue necrosis with either an absent or scanty lymphoid population were observed in the poorly controlled neoplastic specimens obtained in cases in which surgery was undertaken in patients less than 6 months after GKS. Immunohistochemical characterization demonstrated the predominance of CD3-positive T cells in the lymphoid infiltration.

Conclusions.Histopathological findings of the present study are consistent with a cellular immune response of natural killer cells against metastatic brain tumors, presumably stimulated by the ionizing energy of focused radiation.