bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lessons learned in the evolution of endoscopic skull base surgery
Authors: Schwartz Theodore H. , Morgenstern Peter F. , Anand Vijay K. 
Published: February 2019

OBJECTIVEEndoscopic skull base surgery (ESBS) is a relatively recent addition to the neurosurgical armamentarium. As with many new approaches, there has been significant controversy regarding its value compared with more traditional approaches to ventral skull base pathology. Although early enthusiasm for new approaches that appear less invasive is usually high, these new techniques require rigorous study to ensure that widespread implementation is in the best interest of patients.METHODSThe authors compared surgical results for ESBS with transcranial surgery (TCS) for several different pathologies over two different time periods (prior to 2012 and 2012–2017) to see how results have evolved over time. Pathologies examined were craniopharyngioma, anterior skull base meningioma, esthesioneuroblastoma, chordoma, and chondrosarcoma.RESULTSESBS offers clear advantages over TCS for most craniopharyngiomas and chordomas. For well-selected cases of planum sphenoidale and tuberculum sellae meningiomas, ESBS has similar rates of resection with higher rates of visual improvement, and more recent results with lower CSF leaks make the complication rates similar between the two approaches. TCS offers a higher rate of resection with fewer complications for olfactory groove meningiomas. ESBS is preferred for lower-grade esthesioneuroblastomas, but higher-grade tumors often still require a craniofacial approach. There are few data on chondrosarcomas, but early results show that ESBS appears to offer clear advantages for minimizing morbidity with similar rates of resection, as long as surgeons are familiar with more complex inferolateral approaches.CONCLUSIONSESBS is maturing into a well-established approach that is clearly in the patients’ best interest when applied by experienced surgeons for appropriate pathology. Ongoing critical reevaluation of outcomes is essential for ensuring optimal results.
Hearing preservation after Gamma Knife radiosurgery for cerebellopontine angle meningiomas
Authors: El-Shehaby Amr M. N. , Reda Wael A. , Abdel Karim Khaled M. , Nabeel Ahmed M. , Emad Eldin Reem M. , Tawadros Sameh R. 
Published: February 2019

OBJECTIVEThe objective of this study was to assess hearing function after Gamma Knife treatment of cerebellopontine angle (CPA) meningiomas and assess factors affecting hearing outcome. Additionally, the authors opted to compare these results with those after Gamma Knife treatment of vestibular schwannomas (VSs), because most of the information on hearing outcome after stereotactic radiosurgery (SRS) comes from reports on VS treatment. Hearing preservation, to the best of the authors’ knowledge, has never been separately addressed in studies involving Gamma Knife radiosurgery (GKRS) for CPA meningiomas.METHODSThis study included all patients who underwent a single session of GKRS between 2002 and 2014. The patients were divided into two groups. Group A included 66 patients with CPA meningiomas with serviceable hearing and tumor extension into the region centered on the internal auditory meatus. Group B included 144 patients with VSs with serviceable hearing. All patients had serviceable hearing before treatment (Gardner-Robertson [GR] Grades I and II). The median prescription dose was 12 Gy (range 10–12 Gy) in both groups. The median follow-up of groups A and B was 42 months (range 6–149 months) and 49 months (range 6–149 months), respectively.RESULTSAt the last follow-up, the tumor control rate was 97% and 94% in groups A and B, respectively. Hearing preservation was defined as maintained serviceable hearing according to GR hearing score. The hearing preservation rate was 98% and 66% and the 7-year actuarial serviceable hearing preservation rate was 75% and 56%, respectively, between both groups. In group A, the median maximum cochlear dose in the patients with stable and worsened hearing grade was 6.3 Gy and 5.5 Gy, respectively. In group B, factors affecting hearing preservation were cochlear dose ≤ 7 Gy, follow-up duration, and tumor control. The only determinant of hearing preservation between both groups was tumor type.CONCLUSIONSGKRS for CPA meningiomas provides excellent hearing preservation in addition to high tumor control rate. Hearing outcome is better with CPA meningiomas than with VSs. Further long-term prospective studies on determinants of hearing outcome after GKRS for CPA meningiomas should be conducted.
Prognostic grading system specifically for elderly patients with brain metastases after stereotactic radiosurgery: a 2-institution study
Authors: Yamamoto Masaaki , Serizawa Toru , Higuchi Yoshinori , Nagano Osamu , Aiyama Hitoshi , Koiso Takao , Watanabe Shinya , Kawabe Takuya , Sato Yasunori , Kasuya Hidetoshi 
Published: February 2019

OBJECTIVEWith the aging of the population, increasing numbers of elderly patients with brain metastasis (BM) are undergoing stereotactic radiosurgery (SRS). Among recently reported prognostic grading indexes, only the basic score for brain metastases (BSBM) is applicable to patients 65 years or older. However, the major weakness of this system is that no BM-related factors are graded. This prompted the authors to develop a new grading system, the elderly-specific (ES)–BSBM.METHODSFor this IRB-approved, retrospective cohort study, the authors used their prospectively accumulated database comprising 3267 consecutive patients undergoing Gamma Knife SRS for BMs during the 1998–2016 period at the Mito GammaHouse. Among these 3267 patients, 1789 patients ≥ 65 years of age were studied (Yamamoto series [Y-series]). Another series of 1785 patients ≥ 65 years of age in whom Serizawa and colleagues performed Gamma Knife SRS during the same period (Serizawa series [S-series]) was used for validity testing of the ES-BSBM.RESULTSTwo factors were identified as strongly impacting longer survival after SRS by means of multivariable analysis using the Cox proportional hazard model with a stepwise selection procedure. These factors are the number of tumors (solitary vs multiple: HR 1.450, 95% CI 1.299–1.621; p < 0.0001) and cumulative tumor volume (≤ 15 cm3 vs > 15 cm3: HR 1.311, 95% CI 1.078–1.593; p = 0.0067). The new index is the addition of scores 0 and 1 for these 2 factors to the BSBM. The ES-BSBM system is based on categorization into 3 classes by adding these 2 scores to those of the original BSBM. Each ES-BSBM category has 2 possible scores. For the category ES-BSBM 4–5, the score is either 4 or 5; for ES-BSBM 2–3, the score is either 2 or 3; and for ES-BSBM 0–1, the score is either 0 or 1. In the Y-series, the median survival times (MSTs, months) after SRS were 17.5 (95% CI 15.4–19.3) in ES-BSBM 4–5, 6.9 (95% CI 6.4–7.4) in ES-BSBM 2–3, and 2.8 (95% CI 2.5–3.6) in ES-BSBM 0–1 (p < 0.0001). Also, in the S-series, MSTs were, respectively, 20.4 (95% CI 17.2–23.4), 7.9 (95% CI 7.4–8.5), and 3.2 (95% CI 2.8–3.6) (p < 0.0001). The ES-BSBM system was shown to be applicable to patients with all primary tumor types as well as to those 80 years or older.CONCLUSIONSThe authors found that the addition of the number of tumors and cumulative tumor volume as scoring factors to the BSBM system significantly improved the prognostic value of this index. The present study is strengthened by testing the ES-BSBM in a different patient group.
Stereotactic radiosurgery for pituitary adenoma invading the cavernous sinus
Authors: Shin Masahiro , Kurita Hiroki , Sasaki Tomio , Tago Masao , Morita Akio , Ueki Keisuke , Kirino Takaaki 
Published: February 2019

Object. The purpose of this study is to determine the efficacy of gamma knife radiosurgery (GKS) treatment of pituitary adenomas that have invaded the cavernous sinus.
Methods. Sixteen patients were treated with GKS: three with nonfunctional adenomas and 13 with hormone-secreting (seven growth hormone [GH] and six adrenocorticotropic hormone [ACTH]) adenomas. More than 16 Gy and 30 Gy were delivered to the tumor margin for nonfunctioning tumors and functioning tumors, respectively, keeping the dose to the optic pathways below 10 Gy. The median follow up was 3 years.
Tumor growth control was achieved in all cases. In GH-producing tumors, four of six cases evaluated were endocrinologically normalized (serum GH < 10 mIU/L, somatomedin C < 450 ng/ml), and the remaining two cases also showed a steady decrease in the GH and somatomedin level. In ACTH-producing tumors, three of six cases were endocrinologically normalized (24-hour urinary-free cortisol < 90 mg/day), two were unchanged, and one showed hormonal recurrence 3 years after radiosurgery. Notably, there were no cases of permanent hypopituitarism or visual symptoms caused by radiosurgery.
Conclusions. The authors data indicate that GKS can be a safe salvage therapy for invading pituitary adenomas, with effectiveness equivalent to conventional radiation therapy but with less risk of causing radiation-induced injury to the surrounding structures.
Gamma knife radiosurgery for pituitary adenomas
Authors: Izawa Masahiro , Hayashi Motohiro , Nakaya Kohtarou , Satoh Hiroyuki , Ochiai Taku , Hori Tomokatsu , Takakura Kintomo 
Published: February 2019

Object. The purpose of this study was the analysis of a large series of patients treated with gamma knife radiosurgery for pituitary adenoma in a single institution.
Methods. One hundred eight patients with pituitary adenomas were treated over the last 7 years. Seventy-four patients have been followed for more than 6 months and form the basis of this report.
Conclusions. Twenty-three patients harbored nonfunctioning adenomas, and 56 harbored functioning adenomas. The mean margin dose was 22.5 Gy (nonfunctioning adenomas, 19.5 Gy; functioning adenomas, 23.8 Gy). Control of tumor growth was achieved in 91%. A significant decrease of excessive hormone production was seen in 80% of patients, and the endocrinological normalization rate was 30.3%. Postradiosurgical complications were seen in 2.5%.
Gamma knife radiosurgery for simultaneous multiple metastatic brain tumors
Authors: Suzuki Satoshi , Omagari Junichi , Nishio Shunji , Nishiye Eiichiro , Fukui Masashi 
Published: February 2019

Object. The authors assessed the efficacy of gamma knife radiosurgery (GKS) in the treatment of patients with 10 or more simultaneous metastatic brain tumors.
Methods. Gamma knife radiosurgery was performed for the treatment of 10 or more simultaneous metastatic brain tumors in 24 patients. The performance status before and after GKS was expressed using the Karnofsky Performance Scale (KPS). The cumulative survival rate was analyzed using the Kaplan—Meier method. The level of satisfaction with the procedure was assessed by telephone interview.
No patient has died due to brain metastasis—related symptoms, and all patients and/or their families were satisfied with the GKS. In 12 patients who had brain metastasis—related symptoms, five improved, six were unchanged, and one deteriorated, as reflected by the KPS scores. The cumulative survival rate calculated by the Kaplan—Meier method was 70.4%, 49.3%, and 12.3% at 12 weeks, 24 weeks, and 36 weeks, respectively. The median survival time was 11 weeks.
Conclusions. Single-fraction GKS can achieve acceptable tumor control, low morbidity, and good quality of life in the treatment of multiple metastatic brain tumors even in cases with 10 or more simultaneous metastases.
Immediate neurological deterioration after gamma knife radiosurgery for acoustic neuroma
Authors: Tago Masao , Terahara Atsuro , Nakagawa Keiichi , Aoki Yukimasa , Ohtomo Kuni , Shin Masahiro , Kurita Hiroki 
Published: February 2019

✓ The authors describe acute deterioration in facial and acoustic neuropathies following radiosurgery for acoustic neuromas.
In May 1995, a 26-year-old man, who had no evidence of neurofibromatosis Type 2, was treated with gamma knife radiosurgery (GKS; maximum dose 20 Gy and margin dose 14 Gy) for a right-sided intracanalicular acoustic tumor. Two days after the treatment, he developed headache, vomiting, right-sided facial weakness, tinnitus, and right hearing loss. There was a deterioration of facial nerve function and hearing function from pretreatment values. The facial function worsened from House—Brackmann Grade 1 to 3. Hearing deteriorated from Grade 1 to 5. Magnetic resonance (MR) images, obtained at the same time revealed an obvious decrease in contrast enhancement of the tumor without any change in tumor size or peritumoral edema. Facial nerve function improved gradually and increased to House—Brackmann Grade 2 by 8 months post-GKS. The tumor has been unchanged in size for 5 years, and facial nerve function has also been maintained at Grade 2 with unchanged deafness.
This is the first detailed report of immediate facial neuropathy after GKS for acoustic neuroma and MR imaging revealing early possibly toxic changes. Potential explanations for this phenomenon are presented.
Stereotactic radiosurgery versus stereotactic radiotherapy for patients with vestibular schwannoma: a Leksell Gamma Knife Society 2000 debate
Authors: Linskey Mark E. 
Published: February 2019

✓ By definition, the term “radiosurgery” refers to the delivery of a therapeutic radiation dose in a single fraction, not simply the use of stereotaxy. Multiple-fraction delivery is better termed “stereotactic radiotherapy.” There are compelling radiobiological principles supporting the biological superiority of single-fraction radiation for achieving an optimal therapeutic response for the slowly proliferating, late-responding, tissue of a schwannoma. It is axiomatic that complication avoidance requires precise three-dimensional conformality between treatment and tumor volumes. This degree of conformality can only be achieved through complex multiisocenter planning. Alternative radiosurgery devices are generally limited to delivering one to four isocenters in a single treatment session. Although they can reproduce dose plans similar in conformality to early gamma knife dose plans by using a similar number of isocenters, they cannot reproduce the conformality of modern gamma knife plans based on magnetic resonance image—targeted localization and five to 30 isocenters.
A disturbing trend is developing in which institutions without nongamma knife radiosurgery (GKS) centers are championing and/or shifting to hypofractionated stereotactic radiotherapy for vestibular schwannomas. This trend appears to be driven by a desire to reduce complication rates to compete with modern GKS results by using complex multiisocenter planning. Aggressive advertising and marketing from some of these centers even paradoxically suggests biological superiority of hypofractionation approaches over single-dose radiosurgery for vestibular schwannomas. At the same time these centers continue to use the term radiosurgery to describe their hypofractionated radiotherapy approach in an apparent effort to benefit from a GKS “halo effect.” It must be reemphasized that as neurosurgeons our primary duty is to achieve permanent tumor control for our patients and not to eliminate complications at the expense of potential late recurrence. The answer to minimizing complications while maintaining maximum tumor control is improved conformality of radiosurgery dose planning and not resorting to homeopathic radiosurgery doses or hypofractionation radiotherapy schemes.
Gamma knife radiosurgery using 90 Gy for trigeminal neuralgia
Authors: Nicol Bradley , Regine William F. , Courtney Claire , Meigooni Ali , Sanders Michael , Young Byron 
Published: February 2019

Object. The purpose of this paper was to assess the treatment of trigeminal neuralgia (TN) with the higher than normal dose of 90 Gy.
Methods. Forty-two patients with typical TN were treated over a 3-year period with gamma knife radiosurgery. Every patient received a maximum dose of 90 Gy in a single 4-mm isocenter targeted to the root entry zone of the trigeminal nerve. Thirty of 42 patients had undergone no prior treatments. The median follow-up period was 14 months (range 2–30 months).
Thirty-one patients (73.8%) achieved complete relief of pain. Nine patients (21.4%) obtained good pain control. Complications were limited to increased facial paresthesia in seven patients (16.7%) and dysgeusia in four patients (9.5%).
Conclusions. The authors conclude that the use of 90 Gy is a safe and effective dose for the treatment of TN.
Results of repeated gamma knife radiosurgery for medically unresponsive trigeminal neuralgia
Authors: Pollock Bruce E. , Foote Robert L. , Stafford Scott L. , Link Michael J. , Gorman Deborah A. , Schomberg Paula J. 
Published: February 2019

Object. Gamma knife radiosurgery (GKS) is being increasing performed in the management of patients with medically unresponsive trigeminal neuralgia. The authors report the results of repeated GKS in patients with recurrent facial pain after their initial procedure.
Methods. Between April 1997 and December 1999, 100 patients with idiopathic trigeminal neuralgia underwent GKS at the authors' center. To date, 26 patients have required additional surgery because GKS provided no significant pain relief (15 patients) or because they had recurrent facial pain (11 patients). Ten of these patients underwent repeated GKS at a median of 13 months (range 4–27 months). All patients undergoing repeated GKS had a significant reduction in their facial pain after the first procedure (eight were pain free); no patient developed facial numbness or paresthesias. Initially, nine of 10 patients became pain free 1 to 4 weeks following repeated GKS. At a median follow up of 15 months (range 3–32 months), eight patients remained pain free and required no medication. All eight patients with persistent pain relief developed minor neurological dysfunction after repeated GKS (six patients had facial numbness and two had paresthesias).
Conclusions. Repeated GKS can be associated with a high rate of pain relief for patients with trigeminal neuralgia who experienced a significant reduction in their facial pain after the first operation. However, every patient with sustained pain relief after the second operation also developed some degree of trigeminal dysfunction. These findings of improved pain relief for patients who develop facial numbness after GKS for trigeminal neuralgia support the experimental data currently available.
Gamma knife radiosurgery for torsion spasm
Authors: Pan Li , Zhang Nan , Dai Jia Zhong , Wang En Min 
Published: February 2019

✓ The authors report on two patients who underwent radiosurgery for torsion spasm and evaluate the efficiency of gamma knife radiosurgery (GKS) as an alternative treatment.
The first patient was a 33-year-old woman with severe right-sided lower-limb torsion dystonia. The second patient was a 20-year-old man with right-sided upper-limb torsion dystonia. The target was located at the anterior portion of the ventrolateral nucleus. The maximum doses were 150 Gy and 145 Gy, respectively. Double isocenters with a 4-mm collimator were used. Follow up lasted for 18 months and 8 months, respectively. Both patients had excellent clinical improvement 2 to 3 months after GKS, respectively.
The authors believe that GKS may be a safe and efficient treatment for torsion spasm.
A simple scoring ratio to index the conformity of radiosurgical treatment plans
Authors: Paddick Ian 
Published: February 2019

✓ A conformity index is a measure of how well the volume of a radiosurgical dose distribution conforms to the size and shape of a target volume. Because the success of radiosurgery is related to the extremely conformal irradiation of the target, an accurate method for describing this parameter is important. Existing conformity ratios and indices used in radiosurgery are reviewed and criticized. It will be demonstrated that previously proposed measurements of conformity can, under certain conditions, give false perfect scores. A new conformity index is derived that gives an objective score of conformity for a treatment plan and gives no false scores.
An analysis of five different treatment plans is made using both the existing scoring methods and the new conformity index.
Comparison of geometric distortion in digital angiography with and without a correction program
Authors: Zheng Zhen , Shearer Douglas , Norén Georg , Chougule Prakash , Friehs Gerhard 
Published: February 2019

✓ This study was conducted to evaluate the geometric distortion of angiographic images created from a commonly used digital x-ray imaging system and the performance of a commercially available distortion-correction computer program.
A 12 × 12 × 12—cm wood phantom was constructed. Lead shots, 2 mm in diameter, were attached to the surfaces of the phantom. The phantom was then placed inside the angiographic localizer. Cut films (frontal and lateral analog films) of the phantom were obtained. The films were analyzed using GammaPlan target series 4.12. The same procedure was repeated with a digital x-ray imaging system equipped with a computer program to correct the geometric distortion. The distortion of the two sets of digital images was evaluated using the coordinates of the lead shots from the cut films as references.
The coordinates of all lead shots obtained from digital images and corrected by the computer program coincided within 0.5 mm of those obtained from cut films. The average difference is 0.28 mm with a standard deviation of 0.01 mm. On the other hand, the coordinates obtained from digital images with and without correction can differ by as much as 3.4 mm. The average difference is 1.53 mm, with a standard deviation of 0.67 mm.
The investigated computer program can reduce the geometric distortion of digital images from a commonly used x-ray imaging system to less than 0.5 mm. Therefore, they are suitable for the localization of arteriovenous malformations and other vascular targets in gamma knife radiosurgery.
Integration of the metabolic data of positron emission tomography in the dosimetry planning of radiosurgery with the Leksell gamma knife: early experience with brain tumors
Authors: Levivier Marc , Wikier David , Goldman Serge , David Philippe , Metens Thierry , Massager Nicolas , Gerosa Massimo , Devriendt Daniel , Desmedt Françoise , Simon Stephane , Van Houtte Paul , Brotchi Jacques 
Published: February 2019

✓ The purpose of this study was to assess the use of positron emission tomography (PET) as a stereotactic planning modality for gamma knife radiosurgery (GKS).
The authors developed and validated a technique for fiducial marker imaging, importation, and handling of PET data for integration into GammaPlan planning software. The clinical feasibility in applying this approach to a selected group of patients presenting with recurrent glial tumors or metastases was evaluated.
Positron emission tomography data can be integrated into GammaPlan, allowing a high spatial accuracy, as validated using a phantom. Positron emission tomography data were successfully combined with magnetic resonance (MR) images to define the target volume for the radiosurgical treatment of patients with recurrent glioma or metastasis. This approach may contribute to optimizing target selection for infiltrating or ill-defined brain lesions. Because PET is also useful for the pretreatment and follow-up evaluation, the use of stereotactic PET in these patients can enable an accurate comparison of PET-based metabolic data with MR-based anatomical data. This could give a better understanding of the metabolic changes following radiosurgery.
The ability to use PET data in GKS represents a crucial step toward further developments in radiosurgery, as this approach provides additional information that may open new perspectives for the optimization of the treatment of brain tumors.