bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimal timing for Gamma Knife surgery after hemorrhage from brain arteriovenous malformations
Authors: Maruyama Keisuke , Koga Tomoyuki , Shin Masahiro , Igaki Hiroshi , Tago Masao , Saito Nobuhito 
Published: November 2018

Object
Optimal timing of Gamma Knife surgery (GKS) after hemorrhage from brain arteriovenous malformations (AVMs) is unclear and of concern to neurosurgeons because GKS is usually performed after absorption of the hematoma. The authors investigated whether waiting for hematoma absorption is beneficial and aimed to clarify the optimal treatment timing.

Methods
The authors retrospectively studied 211 patients with AVMs who presented with hemorrhage and underwent GKS as the initial treatment. Patients were categorized into 3 groups according to the interval between the time of first hemorrhage and GKS, as follows: Group 1, 0–3 months (70 patients); Group 2, 3–6 months (62 patients); and Group 3, > 6 months (79 patients). The obliteration rates, number of hemorrhages before and after GKS, and complication rates were compared between these 3 groups. The authors also analyzed a subgroup of 127 patients who presented with intracerebral hemorrhage (ICH) to identify the influence of ICH on outcome.

Results
After a median follow-up of 6.3 years, the rates of obliteration, hemorrhage after treatment, and complication were not significantly different between the 3 groups even though the patients with a longer interval before GKS (Group 3) had more AVMs in eloquent areas and neurological deficits. However, the numbers of patients with preoperative hemorrhage in the interval before GKS was significantly higher in Group 3 (1, 3, and 20 patients in Group 1, 2, and 3, respectively). These results were similar in the analyses of 127 patients presenting with ICH.

Conclusions
No benefit was detected in waiting for hematoma absorption until GKS after hemorrhage from AVM. Because of higher hemorrhagic risk until GKS > 6 months after hemorrhage, the authors recommend GKS within 6 months after hemorrhage.
Gamma Knife surgery in the management of radioresistant brain metastases in high-risk patients with melanoma, renal cell carcinoma, and sarcoma
Authors: Powell John W. , Chung Chung T. , Shah Hemangini R. , Canute Gregory W. , Hodge Charles J. , Bassano Daniel A. , Liu Lizhong , Mitchell Lisa , Hahn Seung S. 
Published: November 2018

Object
The purpose of this study was to examine the results of using Gamma Knife surgery (GKS) for brain metastases from classically radioresistant malignancies.

Methods
The authors retrospectively reviewed the records of 76 patients with melanoma (50 patients), renal cell carcinoma (RCC; 23 patients), or sarcoma (3 patients) who underwent GKS between August 1998 and July 2007. Overall patient survival, intracranial progression, and local progression of individual lesions were analyzed.

Results
The median age of the patients was 57 years (range 18–85 years) and median Karnofsky Performance Scale (KPS) score was 80 (range 20–100). Sixty-two patients (81.6%) had uncontrolled extracranial disease. A total of 303 intracranial lesions (average 3.97 per patient, range 1–27 lesions) were treated using GKS. More than 3 lesions were treated in 30 patients (39.5%). Median GKS tumor margin dose was 18 Gy (range 8–30 Gy). Thirty-seven patients (48.7%) underwent whole brain radiation therapy. The actuarial 12-month rate for freedom from local progression for individual lesions was 77.7% and was significantly higher for RCC compared with melanoma (93.6 vs 63.0%; p = 0.001). The percentage of coverage of the prescribed dose to target volume was the only treatment–related variable associated with local control: 12-month actuarial rate of freedom from local progression was 71.4% for lesions receiving ≥ 90% coverage versus 0.0% for lesions receiving < 90% (p = 0.00048). Median overall survival was 5.1 months after GKS and 8.4 months after the discovery of brain metastases. Univariate analysis revealed that KPS score (p = 0.000004), recursive partitioning analysis class (p = 0.00043), and single metastases (p = 0.028), but not more than 3 metastases, to be prognostic factors of overall survival. The KPS score remained significant after multivariate analysis. Overall survival for patients with a KPS score ≥ 70 was 7.1 months compared with 1.3 months for a KPS score ≤ 60 (p = 0.013).

Conclusions
Gamma Knife surgery is an effective treatment option for patients with radioresistant brain metastases. In this setting, KPS score appeared to be a more important factor in predicting survival than having > 3 metastases. Higher rates of local tumor control were achieved for RCC in comparison with melanoma, and this may have an effect on survival in some patients. Although outcomes generally remained poor in this study population, these results suggest that GKS can be considered as a treatment option for many patients with radioresistant brain metastases, even if these patients have multiple lesions.
Retreatment of vestibular schwannomas with Gamma Knife surgery
Authors: Dewan Sheri , Norén Georg 
Published: November 2018

Object
The response rate of vestibular schwannomas (VSs) to radiosurgery has reached the 97% level in several published series. When failure rarely occurs, some controversy has existed as to whether the tumor has to be resected or can be safely retreated with radiosurgery. The authors retrospectively studied the outcome of retreating 11 patients with Gamma Knife surgery (GKS).

Methods
The authors studied 11 patients at the New England Gamma Knife Center who had undergone GKS as a second radiosurgical treatment for VS from 1994 to 2007. One patient underwent proton-beam radiotherapy as the first treatment, and the other 10 patients had undergone GKS initially. Tumor control (size before and after the first and the second treatment) was evaluated using MR imaging to demonstrate the course after the 2 treatments. Facial nerve function (House–Brackmann grading system), trigeminal nerve function, hearing (Gardner–Robertson classification), and any adverse radiation effects were evaluated. The prescription dose was 12 Gy (11–13.2 Gy) for both treatments.

Results
Of the 11 patients, 2 showed increase, 1 had no change, and, in 8, the VS decreased in size after the retreatment. One tumor remained unchanged over the first 6 months, but demonstrated signs of internal necrosis. All patients demonstrated stable facial nerve function. Regarding facial numbness, 2 patients experienced increases, 8 no change, and 1 decreased numbness. There was no functional hearing prior to the second treatment in 10 patients, and hearing was impaired in 1 patient. Adverse radiation effects (slight peduncular edema) were seen in 2 patients after the second treatment, and 1 patient had edema after the first treatment as well.

Conclusions
Vestibular schwannomas can be retreated with GKS with good tumor control response and low risk of toxicity.
Clinical outcomes after Gamma Knife surgery for idiopathic trigeminal neuralgia: review of 76 consecutive cases
Authors: Dellaretti Marcos , Reyns Nicolas , Touzet Gustavo , Sarrazin Thierry , Dubois François , Lartigau Eric , Blond Serge 
Published: November 2018

Object
Stereotactic radiosurgery is an increasingly used, and the least invasive, surgical option for patients with trigeminal neuralgia (TN). In this study, the authors performed a retrospective evaluation of the safety and efficacy of this method for idiopathic TN.

Methods
The authors reviewed data from 76 patients with idiopathic TN who underwent Gamma Knife surgery (GKS). The mean age of the patients was 64 years (range 27–83 years). All patients had typical features of TN. Thirty patients (39.5%) had previously undergone surgery. The intervention consisted of GKS on the retrogasserian cisternal portion of the fifth cranial nerve. The mean maximum GKS dose used was 85.1 Gy (range 75–90 Gy).

Results
Patients were followed-up from 6 to 42 months (mean 20.3 months) after GKS. Complete pain relief was achieved in 83.1% of the patients within 1 year, 70.9% within 2 years, and 62.5% within 3 years. Patients who underwent previous surgery demonstrated a lower rate of pain relief (p < 0.05). Twenty patients (26.3%) reported pain recurrence between 6 and 42 months after treatment. New or worsened persistent trigeminal dysfunction developed after GKS in 16 patients (21%); 8 of these patients described some facial numbness/not bothersome, and 8 reported some facial numbness/somewhat bothersome. None of the patients developed troublesome dysesthesia or anesthesia dolorosa.

Conclusions
Gamma Knife surgery for idiopathic TN proved to be safe and effective and was associated with a particularly low rate of complications.
Low-grade gliomas treated by fractionated gamma knife surgery
Authors: Simonová Gabriela , Novotny Josef , Liscák Roman 
Published: November 2018

Object. The authors sought to evaluate local tumor control, complications, and progression-free survival in patients harboring low-grade gliomas who were treated with Leksell gamma knife surgery (GKS).
Methods. During a 6-year period 70 patients were treated for verified low-grade gliomas (Grade I or II) by GKS. Statistical analysis was based on 68 patients; two patients were lost to follow up. The median patient age was 17 years. The median target volume was 4200 mm.3 The median prescription dose was 25 Gy. The median number of fractions was five. Ninety-five percent of patients were treated in five daily fractions.
Partial or complete tumor regression was achieved in 83% of patients with a median time to response of 18 months. There was moderate acute or late toxicity in not more than 5% of patients. In this series the progression-free survival was 92% at 3 years and 88% at 5 years.
Conclusions. Relatively high local tumor control with minimal complications was achieved.
Gamma knife surgery for hypothalamic hamartomas accompanied by medically intractable epilepsy and precocious puberty: experience in Mexico
Authors: Barajas Marco A. , G. Ramírez-Guzmán Maria , Rodríguez-Vázquez Carlos , Toledo-Buenrostro Vinicio , Cuevas-Solórzano Abel , Rodríguez-Hernández Gabriel 
Published: November 2018

Object. Hypothalamic hamartoma is a nonneoplastic malformative mass of neurons and glia in the region of the hypothalamus. Because of its location, open surgery is associated with high morbidity and mortality rates. Gamma knife surgery (GKS) may be an efficient and safe treatment approach, which produces little morbidity. The authors describe the results of GKS in three patients with hypothalamic hamartomas.
Methods. All patients were male, aged 3, 12, and 15 years. The lesions were classified according to the Valdueza scale: one was Type IIb and two were Type IIa. The patients presented with gelastic seizures (15–20 per day), generalized epilepsy, behavioral abnormalities, and alterations of the sleep cycle. Precocious puberty was present in one patient. The Type IIb tumor had a volume of 1.8 cm3, and the Type IIa tumors were 597 mm3 and 530.1 mm3. The lesions received 12.5 Gy, 14 Gy, and 15 Gy, respectively, to the 50% isodose line. The patients were followed for 30 to 50 months. After 3 months, all patients showed improvement of their sleep, behavior, and epilepsy. At the present time, these patients are receiving low-dose antiepileptic agents and have achieved adequate social development and school integration.
Conclusions. Gamma knife surgery appears to be a good, safe, and effective option for the treatment of selected hypothalamic hamartomas. No morbidity or mortality was associated with these three cases.
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: November 2018

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: November 2018

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.
Gamma knife surgery for brain metastases from lung cancer
Authors: Pan Hung-Chuan , Sheehan Jason , Stroila Matei , Steiner Melita , Steiner Ladislau 
Published: November 2018

Object. The authors conducted a study to evaluate the safety and efficacy of gamma knife surgery (GKS) for the treatment of brain metastases from lung cancer.
Methods. Between February 1993 and May 2003 191 patients underwent treatment for 424 brain metastases from non—small (171 cases) and small cell lung carcinoma (20 cases). Imaging and clinical status were monitored every 3 months following the treatment. Kaplan-Meier survival curves, Cox proportional hazards regression for risk factor analysis, and nonparametric methods for evaluating tumor response were used.
There was no difference in median survival following combined whole-brain radiation therapy (WBRT) and gamma knife surgery (14 months) and GKS alone (15 months). There was also no difference between the median survival rates for either tumor type. In the multivariate analysis, age less than 65 years, Karnofsky Performance Scale score greater than 70, normal neurological status, multiple GKS treatments, and pre-GKS craniotomy were related to longer survival.
Tumor control rates varied according to the volume of the metastases and were as follows: 84.4% (< 0.5 cm3), 94% (0.5–2 cm3), 89.1% (2–4 cm3), 93.4% (4–8 cm3), 85.7% (8–14 cm3), and 87.5% (> 14 cm3). Four lesions required post-GKS craniotomy due to swelling or rapid tumor progression. The rate of tumor shrinkage was higher when a volume was 2 cm3, lower in cystic lesions, lower in tumors with previous WBRT, and lower for margin doses less than 14 Gy.
Conclusions. The risk—benefit ratio of GKS in this series was satisfactory. There was no difference in response rates of the two tumor types, and WBRT did not improve the duration of survival.
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: November 2018

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.
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: November 2018

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.
Gamma knife thalamotomy for movement disorders: evaluation of the thalamic lesion and clinical results
Authors: Ohye Chihiro , Shibazaki Tohru , Sato Sumito 
Published: November 2018

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: November 2018

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.3 The 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.