bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
Gamma knife surgery of brain cavernous hemangiomas
Authors: Liscák Roman , Vladyka Vilibald , Simonová Gabriela , Vymazal Josef , Novotny Josef 
Published: May 2009

Object.The authors conducted a study to record more detailed information about the natural course and factors predictive of outcome following gamma knife surgery (GKS) for cavernous hemangiomas.Methods.One hundred twelve patients with brain cavernous hemangiomas underwent GKS between 1993 and 2000. The median prescription dose was 16 Gy. One hundred seven patients were followed for a median of 48 months (range 6–114 months). The rebleeding rate was 1.6%, which is not significantly different with that prior to radiosurgery (2%). An increase in volume was observed in 1.8% of cases and a decrease in 45%. Perilesional edema was detected in 27% of patients, which, together with the rebleeding, caused a transient morbidity rate of 20.5% and permanent morbidity rate of 4.5%. Before radiosurgery 39% of patients suffered from epilepsy and this improved in 45% of them. Two patients with brainstem cavernous hemangiomas died due to rebleeding. Rebleeding was more frequent in female middle-aged patients with a history of bleeding, a larger lesion volume, and a prescription dose below 13 Gy. Edema after GKS occurred more frequently in patients who had surgery, a larger lesion volume, and in those in whom the prescription dose was more than 13 Gy.Conclusions.Gamma knife surgery of cavernous hemangiomas can produce an acceptable rate of morbidity, which can be reduced by using a lower margin dose. Lesion regression was observed in many patients. Radiosurgery seems to remain a suitable treatment modality in carefully selected patients.
Progress in glaucoma treatment research: a nonrandomized prospective study of 102 patients with advanced refractory glaucoma treated by Leksell gamma knife irradiation
Authors: Vladyka Vilibald , Lis˘c˘ák R. , S˘imonová G. , Pilbauer J. , Hejduková I. , Novác˘ek L. 
Published: May 2009

Object.The authors performed a study to characterize the effects of ciliary body gamma knife surgery (GKS) for advanced glaucoma.Methods.In addition to a pilot project involving 14 patients, 88 other patients were treated. Four 8-mm isocenters were used. Blind eyes received 20 Gy to the 50% isodose. If there was preserved vision the dose was 15 Gy. The median follow up was 20 months (range 2–54 months).Severe pain was present in 93% of patients with secondary glaucoma; after GKS it was substantially improved in 89% of cases. In primary open angle glaucoma, the pain was less frequent and severe. In more than half the patients it disappeared during a median latency of 6 weeks. The median intraocular pressure value was lowered in patients with secondary glaucoma (from 51.3–27 mm Hg). The same values for primary glaucoma were 25.3 and 16.1 mm Hg, respectively, after a median latency of 12 weeks. Twenty-seven of 40 patients with neovascular glaucoma showed a marked reduction of neovascularization after a median latency of 18 weeks. Treatment complications were slight. There was postoperative lacrimation in 61%. Two patients underwent postirradiation cataract extraction. Noninfectious keratitis was observed in two patients. Pharmacotherapy could be reduced in all patients and ceased in approximately one third. There has been no recurrence of the initial symptoms and no worsening of visual acuity.Conclusions.Gamma knife surgery ameliorates the main symptoms in advanced glaucomas and precludes the need for eventual ocular enucleation.
Long-term results of Leksell gamma knife surgery for trigeminal schwannomas
Authors: Pan Li , Wang En-Min , Zhang Nan , Zhou Liang-Fu , Wang Bing-Jiang , Dong Ya-Fei , Dai Jia-Zhong , Cai Pei-Wu 
Published: May 2009

Object. The authors evaluated the long-term efficacy of gamma knife surgery (GKS) in patients with trigeminal schwannomas.
Methods. Fifty-six patients, 31 women and 25 men (mean age 42 years), underwent GKS for trigeminal schwannomas. Fourteen had previously undergone surgery, and GKS was the primary treatment in the remaining 42 patients. The mean target volume was 8.7 cm3 (range 0.8–33 cm3); the mean maximum dose was 27 Gy (range 20–40 Gy); the mean tumor margin dose was 13.3 Gy (range 10–15 Gy); and the mean follow-up period was 68 months (range 27–114 months).
Disappearance of the tumor occurred in seven patients. An obvious decrease in tumor volume was observed in 41 patients, four tumors remained unchanged, and four tumors progressed at 5, 26, 30, and 60 months, respectively. One patient with disease progression died of tumor progression at 36 months after GKS. The tumor growth control rate in this group was 93% (52 of 56 cases).
Mild numbness or diplopia was relieved completely in 14 patients. Improvement of other neurological deficits was demonstrated in 25 patients. Trigeminal nerve dysfunction was either unchanged or slightly worse in 13 patients after GKS. Four patients experienced mild symptom deterioration related to tumor progression.
Conclusions. Radiosurgery proved to be an effective treatment for small- and medium-sized trigeminal schwannomas. Some larger tumors are also suitable for radiosurgery if there is no significant brainstem compression.
Radiosurgery for patients with recurrent small cell lung carcinoma metastatic to the brain: outcomes and prognostic factors
Authors: Sheehan Jason , Kondziolka Douglas , Flickinger John , Lunsford L. Dade 
Published: May 2009

Object.Lung carcinoma is the leading cause of death from cancer. More than 50% of those with small cell lung cancer develop a brain metastasis. Corticosteroid agents, radiotherapy, and resection have been the mainstays of treatment. Nonetheless, median survival for patients with small cell lung carcinoma metastasis is approximately 4 to 5 months after cranial irradiation. In this study the authors examine the efficacy of gamma knife surgery for treating recurrent small cell lung carcinoma metastases to the brain following tumor growth in patients who have previously undergone radiation therapy, and they evaluate factors affecting survival.Methods.A retrospective review of 27 patients (47 recurrent small cell lung cancer brain metastases) undergoing radiosurgery was performed. Clinical and radiographic data obtained during a 14-year treatment period were collected. Multivariate analysis was utilized to determine significant prognostic factors influencing survival.The overall median survival was 18 months after the diagnosis of brain metastases. In multivariate analysis, factors significantly affecting survival included: 1) tumor volume (p = 0.0042); 2) preoperative Karnofsky Performance Scale score (p = 0.0035); and 3) time between initial lung cancer diagnosis and development of brain metastasis (p = 0.0127). Postradiosurgical imaging of the brain metastases revealed that 62% decreased, 19% remained stable, and 19% eventually increased in size. One patient later underwent a craniotomy and tumor resection for a tumor refractory to radiosurgery and radiation therapy. In three patients new brain metastases were demonstrating on follow-up imaging.Conclusions.Stereotactic radiosurgery for recurrent small cell lung carcinoma metastases provided effective local tumor control in the majority of patients. Early detection of brain metastases, aggressive treatment of systemic disease, and a therapeutic strategy including radiosurgery can extend survival.