bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gamma knife surgery for brain metastases in patients harboring four or more lesions: survival and prognostic factors
Authors: Nam Taek-Kyun , Lee Jung-Il , Jung Young-Jo , Im Yong-Seok , An Hee-Ye , Nam Do-Hyun , Park Kwan , Kim Jong-Hyun 
Published: May 2009

Object.This study was performed to evaluate the role of gamma knife surgery (GKS) in patients with a large number (four or more) of metastatic brain lesions.Methods.The authors retrospectively reviewed the outcome in 130 patients who underwent GKS for metastatic lesions. Eighty-four patients presented with one to three lesions (Group A) and 46 presented with four or more lesions (Group B). The overall median survival time after GKS was 35 weeks. The median survival time in Group A (48 weeks) was significantly longer (p = 0.005) than the survival time in Group B (26 weeks). The recursive partitioning analysis (RPA) class was the only significant prognostic factor identified in multivariate analysis. The median survival for patients in RPA Classes I, II, and III was 72, 48, and 19 weeks, respectively, in Group A and 36 and 13 weeks for Classes II and III in Group B. The number of lesions, tumor volume, whole brain radiotherapy, primary tumor site, age, and sex did not affect survival significantly.Conclusions.It is suggested that GKS provides an increase in survival time even in patients with a large number (four or more) of metastatic lesions. Concerning the selection of patients for GKS, RPA class should be considered as the most important factor and multiplicity of the lesions alone should not be a reason for withholding GKS.
Pineal tumors: analysis of treatment results in 20 patients
Authors: Amendola Beatriz E. , Wolf Aizik , Coy Sammie R. , Amendola Marco A. , Eber Daryl 
Published: May 2009

Object. The authors evaluate their results when using gamma knife surgery (GKS) in the management of patients with tumors in the pineal region.
Methods. This is a retrospective clinical evaluation of 20 patients with primary tumors of the pineal region treated with GKS from November 1994 through August 2003. There were 13 germ cell tumors, two pineoblastomas, two low-grade gliomas, one primitive neuroectodermal tumor, one teratoma, and one pineocytoma. There were 10 male and 10 female patients. Their median age was 15.5 years (range 5–71 years). The median margin dose was 11 Gy (range 8–20 Gy). The median target volume was 3.1 cm3 (range 0.1–49.9 cm3). Five patients received sequential systemic chemotherapy and four underwent adjuvant conventional radiation therapy. Seventeen (85%) of 20 patients are alive with a median survival of 30.4 months (range 0–-85.7 months). Two patients required retreatment. Three patients died: one of unrelated causes, one who presented with extensive local disease, and the other of meningeal carcinomatosis with local control of the primary tumor. No complications from GKS were noted.
Conclusions. This initial experience suggests that GKS is a valuable treatment modality for the management of pineal region tumors. This technique offers excellent local tumor control and minimal patient morbidity, allowing for immediate use of systemic chemotherapy and/or conventional radiation if indicated.
Gamma knife surgery for trigeminal neuralgia: improved initial response with two isocenters and increasing dose
Authors: Alpert Tracy E. , Chung Chung T. , Mitchell Lisa T. , Hodge Charles J. , Montgomery Craig T. , Bogart Jeffrey A. , Kim Daniel Y-J. , Bassano Danel A. , Hahn Seung S. 
Published: May 2009

Object.The authors sought to evaluate the initial response of trigeminal neuralgia (TN) to gamma knife surgery (GKS) based on the number of shots delivered and radiation dose.Methods.Between September 1998 and September 2003, some 63 patients with TN refractory to medical or surgical management underwent GKS at Upstate Medical University. Ten patients had multiple sclerosis and 25 patients had undergone prior invasive treatment. Gamma knife surgery was delivered to the trigeminal nerve root entry zone in one shot in 27 patients or two shots in 36 patients. The radiation dose was escalated to less than or equal to 80 Gy in 20 patients, 85 Gy in 21 patients, and greater than or equal to 90 Gy in 22 patients. Pain before and after GKS was assessed using the Barrow Neurological Institute Pain Scale and the improvement score was analyzed as a function of dose grouping and number of shots.Sixty patients were available for evaluation, with an initial overall and complete response rate of 90% and 27%, respectively. There was a greater improvement score for patients who were treated with two shots compared with one shot, mean 2.83 compared with 1.72 (p < 0.001). There was an increased improvement in score at each dose escalation level: less than or equal to 80 Gy (p = 0.017), 85 Gy (p < 0.001), and greater than or equal to 90 Gy (p < 0.001). Linear regression analysis also indicated that there was a greater response with an increased dose (p = 0.021). Patients treated with two shots were more likely to receive a higher dose (p < 0.001). There were no severe complications. Five patients developed mild facial numbness.Conclusions.Gamma knife surgery is an effective therapy for TN. Initial response rates appear to correlate with the number of shots and dose.
Volume reduction in meningiomas after gamma knife surgery
Authors: Feigl Guenther C. , Bundschuh Otto , Gharabaghi Alireza , Samii Madjid , Horstmann Gerhard A. 
Published: May 2009

Object.The purpose of this study was to evaluate the volume-reducing effects of gamma knife surgery (GKS) of meningiomas with and without previous surgical treatment.Methods.A group of 127 patients with a mean age of 57.1 years (range 9–81 years) with 142 meningiomas (128 World Health Organization Grade I and 14 Grade II) were included in this study. The management strategy reduces tumor volume with surgery when necessary (81 patients). Stereotactic GKS with a Gamma Knife model C was performed in all tumors of suitable size. Magnetic resonance imaging follow-up examinations with volumetric tumor analysis was performed 6 months after treatment and annually thereafter.The mean tumor volume was 5.9 cm3(range < 5 to > 40 cm3). The mean follow-up time after GKS was 29.3 months (range 11–61 months). The mean prescription dose was 13.8 Gy (range 10–18 Gy). A reduction in volume occurred in 117 (82.4%) of all tumors, and in 20 tumors (14.1%) growth ceased. The overall tumor control rate of 96.4%. The mean volume reduction achieved with GKS was more than 46.1%. Only five tumors (3.5%) showed a volume increase.Conclusions.Gamma knife surgery was effective in reducing meningioma volume at short-term follow up. Further studies are needed to examine the development of these findings over a longer period.
Gamma knife thalamotomy for movement disorders: evaluation of the thalamic lesion and clinical results
Authors: Ohye Chihiro , Shibazaki Tohru , Sato Sumito 
Published: May 2009

Object.The authors studied the effects of gamma knife thalamotomy (GKT) on Parkinson disease-related tremor and essential tremor before and after reloading of radioactive cobalt.Methods.Based on experience in stereotactic thalamotomy aided by depth microrecording, the target was located at the lateral border of the thalamic ventralis intermedius nucleus (VIM). For more precise targeting, the percentage representation of the thalamic VIM in relation to the entire thalamic length is useful. The location of the target was determined on magnetic resonance (MR) imaging and computerized tomography scanning. A maximum dose of 130 Gy was delivered to the target by using a single isocenter with the 4-mm collimator. In more recent cases, a systematic follow-up examination was performed at 3, 6, 12, 18, and 24 months after GKT.Since 1993, the authors have treated 70 patients with PD. Throughout the series the same dosimetric technique has been used. The course after GKT was compared between the 25 cases with PD treated before reloading and the 35 cases treated after reloading. In the majority (80–85%) treated after reloading, tremor and rigidity were reduced around 6 months after GKT. In the cases treated before reloading this effect took approximately 1 year. The thalamic reaction on MR imaging showed the same two lesion types in both series: a restricted and a diffuse. After reloading the restricted lesion was more frequent and the lesion volume was smaller.Conclusions.The shorter delay in clinical improvement and smaller lesion size may be related to an increased radiation dose.
Prolonged survival in a subgroup of patients with brain metastases treated by gamma knife surgery
Authors: Yu C. P. , Cheung Joel Y. C. , Chan Josie F. K. , Leung Samuel C. L. , Ho Robert T. K. 
Published: May 2009

Object.The authors analyzed the factors involved in determining prolonged survival (≥ 24 months) in patients with brain metastases treated by gamma knife surgery (GKS).Methods.Between 1995 and 2003, a total of 116 patients underwent 167 GKS procedures for brain metastases. There was no special case selection. Smaller and larger lesions were treated with different protocols. The mean patient age was 56.9 years, the mean number of initial lesions was 3.15, and the mean lesion volume was 10.45 cm.3The mean follow-up time was 9.2 months.The median patient survival was 8.68 months. One-, 2-, 3-, 4-, and 5-year actuarial survival rates were 31.8%, 19.8%, 14.6%, 7.7%, and 6.9%, respectively. Patient age, number of lesions at presentation, and lesion volume had no influence on patient survival. Twenty-three (19.8%) patients survived for 24 months or more. Certain factors were associated with increased survival time. These were stable primary disease (21 of 23 patients), a long latency between diagnosis of the primary tumor and the occurrence of brain metastases (mean 28.4 months, median 16 months), absence of third-organ involvement, and repeated local procedures. Ten patients underwent repeated GKS (mean 3.4 per patient). Seven patients required open surgery for local treatment failures (recurrence or radiation necrosis). Two patients had both. Fifteen patients underwent repeated procedures.Conclusions.Aggressive local therapy with GKS, repeated GKS, and GKS plus surgery can achieve increased survival in a subgroup of patients with stable primary disease, no third-organ involvement, and long primary-brain secondary intervals.
Initial experience with gamma knife surgery for endocrine ophthalmopathy
Authors: Antico Julio C. , Crovetto Luis , Tenca Eduardo , Artes Carlos 
Published: May 2009

Object. The aim of this study was to evaluate both the effectiveness and safety of the treatment of endocrine ophthalmopathy with gamma knife surgery (GKS).
Methods. Five patients were included in a prospective study designed to assess the results of GKS of endocrine ophthalmopathy secondary to Graves disease. All the patients completed a 2-year follow-up period. During this period, the patients were evaluated both clinically and by means of additional methods, including computerized tomography and magnetic resonance imaging studies. The minimum dose delivered to the 50% isodose line was 6.5 Gy in all the patients.
In all cases, a clinical improvement was observed. The best effect was seen in symptom regression related to soft-tissue involvement. No treatment-related side effects were detected.
Conclusions. In light of the results obtained the authors consider that GKS may be a safe and effective way to treat endocrine ophthalmopathy.
Gamma knife surgery for refractory postherpetic trigeminal neuralgia: targeting in one session both the retrogasserian trigeminal nerve and the centromedian nucleus of the thalamus
Authors: Keep Marcus F. , DeMare Paul A. , Ashby Lynn S. 
Published: May 2009

Object.The authors tested the hypothesis that two targets are needed to treat postherpetic trigeminal neuralgia (TN): one in the trigeminal nerve for the direct sharp pain and one in the thalamus for the diffuse burning pain.Methods.Three patients with refractory postherpetic TN were treated with gamma knife surgery (GKS) through a novel two-target approach. In a single treatment session, both the trigeminal nerve and centromedian nucleus were targeted. First, the trigeminal nerve, ipsilateral to the facial pain, was treated with 60 to 80 Gy. Second, the centromedian nucleus was localized using standard coordinates and by comparing magnetic resonance images with a stereotactic atlas. A single dose of 120 to 140 Gy was delivered to the target point with a single 4-mm isocenter. Patients were followed clinically and with neuroimaging studies. Pain relief was scored as excellent (75–100%), good (50–75%), poor (25–50%), or none (0–25%). Follow up ranged from 6 to 53 months.There were no GKS-related complications. Two patients died of unrelated medical illnesses but had good or excellent pain relief until death. One patient continues to survive with 44 months follow up and no decrease in pain intensity, but with a decreased area of pain.Conclusions.Combined GKS of the centromedian nucleus and trigeminal nerve in a single treatment session is feasible and safe, and the effect was promising. A larger study is required to confirm and expand these results.
Gamma knife surgery for atypical meningiomas
Authors: Huffmann Beate C. , Reinacher Peter C. , Gilsbach Joachim M. 
Published: May 2009

Object. Complete resection is the optimal treatment for atypical meningiomas (AMs) but its feasibility depends on the tumor site. The object of this study was to assess the effect of gamma knife surgery (GKS) on AM.
Methods. In 15 patients 21 AMs were treated by GKS. Four patients had residual lesions and 10 patients had recurrent tumors after one or more microsurgical interventions. Three patients were treated twice with GKS because of tumor tissue outside the treatment volume, either at the margin or at a distant location. The median clinical and neuroimaging follow-up period was 35 months (range 21–67 months).
Ten tumors shrank 6 to 12 months after GKS, 10 remained stable, and one grew. Between 18 and 36 months after GKS, four patients had a distant recurrence, and two had a margin recurrence. In one of these cases, an additional local recurrence was demonstrated 1 year later, and the patient underwent standard radiotherapy. No patient suffered persistent adverse effects after radiosurgery.
Conclusions. After early tumor shrinkage, high recurrence rates were demonstrated both at the treatment margin and at distant locations in cases treated for AM. There was only one recurrence within the GKS radiation field. For small- and medium-sized AMs GKS may be a safe adjunct to other treatment modalities.
Tumor recurrence and survival following gamma knife surgery for brain metastases
Authors: Mindermann Thomas 
Published: May 2009

Object.The authors evaluated prognostic factors for tumor recurrence and patient survival following gamma knife surgery (GKS) for brain metastasis.Methods.A retrospective review of 101 patient charts was undertaken for those patients treated with GKS for brain metastases from 1994 to 2001.Recurrence rates of brain metastasis following GKS depended on the duration of patient survival. Long-term survival was associated with a higher risk of tumor recurrence and shorter-term survival was associated with a lower risk. The duration of survival following GKS for brain metastases seems to be characteristic of the primary disease rather than the cerebral disease.Conclusions.Recurrence rates of brain metastasis following GKS are related to duration of survival, which is in turn mostly dependent on the nature and course of the primary tumor.
Hemodynamic changes due to stent placement in bifurcating intracranial aneurysms
Authors: Cantón Gádor , Levy David I. , Lasheras Juan C. 
Published: May 2009

Object
The aim of this study was to measure changes in intraaneurysm flow dynamics and mechanical stresses resulting from the placement of Neuroform stents in bifurcating intracranial aneurysm models.

Methods
A digital particle image velocimetry (DPIV) system was used to measure the pulsatile velocity and shear stress fields within the aneurysm and at the aneurysm neck—parent artery interface. The DPIV system provides an instantaneous two-dimensional measurement of the temporal and spatial variations of the velocity vector field of the flow inside the aneurysm pouch and the parent vessel, providing information on both the temporal and spatial variations of the velocity field during the entire cardiac cycle. The corresponding shear stress field was then computed from the velocity field data. A flexible silicone model of bifurcating intracranial aneurysms was used. Two Neuroform stents with a 60- to 65-µm strut thickness and an 11% metal/artery ratio were placed in a Y-configuration, and measurements were obtained after placing the stents.

Conclusions
Two three-dimensional vortices of different strengths persisted within the aneurysm during the entire cardiac cycle. The peak velocity and strength of these vortices were reduced after placing the two bifurcating stents. The effect of placing the Neuroform stent across the neck of a bifurcating intracranial aneurysm was shown to reduce the magnitude of the velocity of the jet entering the sac by as much as 11%. Nevertheless, the effect of the stents was particularly noticeable at the end of the cardiac cycle, when the residual vorticity and shear stresses inside the sac were decreased by more than 40%.
Use of side branch in saphenous vein interposition graft for high-flow EC/IC bypass procedures
Authors: Rivet Dennis J. , Wanebo John E. , Roberts Gareth A. , Dacey Ralph G. 
Published: May 2009

✓ Saphenous vein (SV) interposition grafts are often used for high-flow extracranial—intracranial bypass procedures. During these procedures, it is essential to remove air and debris from the graft and to evaluate blood flow through the graft after it has been anastomosed to other cortical vessels.
In this paper, the authors describe the preservation of a large side branch on the proximal end of the SV. This side branch can be used to flush out air and debris from the graft and to evaluate blood flow during revascularization.
Linear accelerator surgery for meningiomas
Authors: Friedman William A. , Murad Gregory J. , Bradshaw Patrick , Amdur Robert J. , Mendenhall William M. , Foote Kelly D. , Bova Frank J. 
Published: May 2009

Object. In this paper the authors review the results of a single-center experience in the use of linear accelerator (LINAC) surgery for radiosurgical treatment of meningiomas.
Methods. A retrospective analysis of all patients treated with LINAC surgery for meningiomas between May 1989 and December 2001 was performed. All patients participated in follow-up review for a minimum of 2 years, and no patients were excluded. Two hundred ten patients were treated during the study interval.
The actuarial local control rate for benign tumors was 100% at both 1 and 2 years, and 96% at 5 years. The actuarial local control rate for atypical tumors was 100% at 1 year, 92% at 2 years, and 77% at 5 years; and that for malignant tumors was 100% at both 1 and 2 years, and only 19% at 5 years. Of the 210 patients 13 (6.2%) experienced temporary radiation-induced complications, and only five (2.3%) experienced permanent complications. In all patients with a permanent complication the histological characteristics of the meningioma were malignant.
Conclusions. Linear accelerator surgery produced high local control rates and very low rates of permanent morbidity in patients harboring benign meningiomas.
Case—control study of stereotactic radiosurgery for recurrent glioblastoma multiforme
Authors: Mahajan Anita , McCutcheon Ian E. , Suki Dima , Chang Eric L. , Hassenbusch Samuel J. , Weinberg Jeffrey S. , Shiu Almon , Maor Moshe H. , Woo Shiao Y. 
Published: May 2009

Object. The role of stereotactic radiosurgery (SRS) for recurrent glioblastoma multiforme (GBM) was evaluated in a case—control study.
Methods. All patients who underwent SRS for recurrent GBM before March 2003 formed the case group. A control group of patients who did not undergo SRS was created from an institutional database, and each case was matched for known prognostic factors in GBM. The medical and neuroimaging records of all the patients were reviewed, and survival and treatment outcomes were recorded.
The case and control groups were well matched with regard to demographics and pre-SRS interventions. In the control group, the date on which magnetic resonance imaging identified a recurrent lesion that would have been eligible for SRS was deemed the “SRS” date. The number of surgeries performed in the control group was statistically higher than that in the case group. The median duration of overall survival from diagnosis was 26 months in the case group and 23 months in the control group. From the date of SRS or “SRS”, the median duration of survival was 11 months in the case group and 10 months in the control group, a difference that was not statistically significant.
Conclusions. It appears that a subgroup of patients with GBMs has a higher than expected median survival duration despite the initial prognostic factors. In patients with localized recurrences, survival may be prolonged by applying aggressive local disease management by using either SRS or resection to equal advantage.
Psychiatric symptoms in patients with Parkinson disease presenting for deep brain stimulation surgery
Authors: Voon Valerie , Saint-Cyr Jean , Lozano Andres M. , Moro Elena , Poon Yu Yan , Lang Anthony E. 
Published: May 2009

Object. Postoperative psychiatric symptoms have been associated with subthalamic deep brain stimulation (DBS) for Parkinson disease (PD), and preoperative psychiatric vulnerability, the effects of surgery, stimulation, medication changes, and psychosocial adjustment have been proposed as causative factors. The variables involved in whether preoperative psychiatric symptoms improve or worsen following surgery are not yet known. In the present study, preoperative psychiatric symptoms were systematically assessed in patients with PD presenting for routine preoperative psychiatric assessment.
Methods. Forty consecutive patients with PD presenting for DBS were interviewed using the Mini International Neuropsychiatric Inventory. Current depressive symptoms were quantified using clinician- and patient-rated depression scales. Seventy-eight percent of patients had at least one lifetime or current Axis I psychiatric diagnosis. The prevalence of depression was 60% (95% confidence interval [CI] 45–85), psychosis 35% (95% CI 25–50), and anxiety 40% (95% CI 25–55). These prevalence rates were comparable to or greater than those in the general population of patients with PD. Twenty-three percent of patients required psychiatric treatment for current symptoms prior to being considered eligible for DBS.
Conclusions. As part of the selection process for surgery, members of the study population were chosen for their lack of overt dementia or other active disabling psychiatric symptomatology. The incidence rates of psychiatric disorders, including those diseases occurring in the general population affected with PD, were greater than expected. Data in the present study lead one to question the reliability of patient-rated depression scales as the sole instrument for assessing depression. The authors highlight the need for evidence-based guidelines in the management of these preoperative symptoms as well as the involvement of psychiatric personnel in the assessment and management of these symptoms.