bluuebunny/crossref_metadata_2025_split huggingface dataset:
Repeat Gamma Knife surgery for recurrent trigeminal neuralgia: long-term outcomes and systematic review
Authors: Tuleasca Constantin , Carron Romain , Resseguier Noémie , Donnet Anne , Roussel Philippe , Gaudart Jean , Levivier Marc , Régis Jean 
Published: November 2018

ObjectThe purpose of this study was to establish the safety and efficacy of repeat Gamma Knife surgery (GKS) for recurrent trigeminal neuralgia (TN).MethodsUsing the prospective database of TN patients treated with GKS in Timone University Hospital (Marseille, France), data were analyzed for 737 patients undergoing GKS for TN Type 1 from July 1992 to November 2010. Among the 497 patients with initial pain cessation, 34.4% (157/456 with ≥ 1-year follow-up) experienced at least 1 recurrence. Thirteen patients (1.8%) were considered for a second GKS, proposed only if the patients had good and prolonged initial pain cessation after the first GKS, with no other treatment alternative at the moment of recurrence. As for the first GKS, a single 4-mm isocenter was positioned in the cisternal portion of the trigeminal nerve at a median distance of 7.6 mm (range 4–14 mm) anterior to the emergence of the nerve (retrogasserian target). A median maximum dose of 90 Gy (range 70–90 Gy) was delivered. Data for 9 patients with at least 1-year followup were analyzed. A systematic review of literature was also performed, and results are compared with those of the Marseille study.ResultsThe median time to retreatment in the Marseille study was 72 months (range 12–125 months) and in the literature it was 17 months (range 3–146 months). In the Marseille study, the median follow-up period was 33.9 months (range 12–96 months), and 8 of 9 patients (88.9%) had initial pain cessation with a median of 6.5 days (range 1–180 days). The actuarial rate for new hypesthesia was 33.3% at 6 months and 50% at 1 year, which remained stable for 7 years. The actuarial probabilities of maintaining pain relief without medication at 6 months and 1 year were 100% and 75%, respectively, and remained stable for 7 years. The systematic review analyzed 20 peer-reviewed studies reporting outcomes for repeat GKS for recurrent TN, with a total of 626 patients. Both the selection of the cases for retreatment and the way of reporting outcomes vary widely among studies, with a median rate for initial pain cessation of 88% (range 60%–100%) and for new hypesthesia of 33% (range 11%–80%).ConclusionsResults from the Marseille study raise the question of surgical alternatives after failed GKS for TN. The rates of initial pain cessation and recurrence seem comparable to, or even better than, those of the first GKS, according to different studies, but toxicity is much higher, both in the Marseille study and in the published data. Neither the Marseille study data nor literature data answer the 3 cardinal questions regarding repeat radiosurgery in recurrent TN: which patients to retreat, which target is optimal, and which dose to use.
Fivefold higher rate of pseudarthrosis with polyetheretherketone interbody device than with structural allograft used for 1-level anterior cervical discectomy and fusion
Authors: Krause Katie L. , Obayashi James T. , Bridges Kelly J. , Raslan Ahmed M. , Than Khoi D. 
Published: November 2018

OBJECTIVECommon interbody graft options for anterior cervical discectomy and fusion (ACDF) include structural allograft and polyetheretherketone (PEEK). PEEK has gained popularity due to its radiolucency and its elastic modulus, which is similar to that of bone. The authors sought to compare the rates of pseudarthrosis, a lack of solid bone growth across the disc space, and the need for revision surgery with the use of grafts made of allogenic bone versus PEEK.METHODSThe authors retrospectively reviewed 127 cases in which patients had undergone a 1-level ACDF followed by at least 1 year of radiographic follow-up. Data on age, sex, body mass index, tobacco use, pseudarthrosis, and the reoperation rate for pseudarthrosis were collected. These data were analyzed by performing a Pearson’s chi-square test.RESULTSOf 127 patients, 56 had received PEEK implants and 71 had received allografts. Forty-six of the PEEK implants (82%) were stand-alone devices. There were no significant differences between the 2 treatment groups with respect to patient age, sex, or body mass index. Twenty-nine (52%) of 56 patients with PEEK implants demonstrated radiographic evidence of pseudarthrosis, compared to 7 (10%) of 71 patients with structural allografts (p < 0.001, OR 9.82; 95% CI 3.836–25.139). Seven patients with PEEK implants required reoperation for pseudarthrosis, compared to 1 patient with an allograft (p = 0.01, OR 10.00; 95% CI 1.192–83.884). There was no significant difference in tobacco use between the PEEK and allograft groups (p = 0.586).CONCLUSIONSThe results of this study demonstrate that the use of PEEK devices in 1-level ACDF is associated with a significantly higher rate of radiographically demonstrated pseudarthrosis and need for revision surgery compared with the use of allografts. Surgeons should be aware of this when deciding on interbody graft options, and reimbursement policies should reflect these discrepancies.
Gamma knife radiosurgery in the treatment of Cushing disease: long-term results
Authors: Kobayashi Tatsuya , Kida Yoshihisa , Mori Yoshimasa 
Published: November 2018

Object. The authors sought to analyze the long-term outcome of patients with Cushing disease who underwent gamma knife radiosurgery (GKS) as either an adjuvant or primary treatment.
Methods. Twenty-five patients with Cushing disease were treated by GKS and followed for more than 2.5 years (mean 5.3 years).
The overall results showed a complete response rate of 30%, a response rate of 85%, and a tumor control rate of 100%. Tumor size and radiation dose were the most important factors related to the treatment response. The complete response rate for microadenomas and small adenomas was significantly higher than that for macroadenomas. An 83.2% complete response rate was obtained using a maximum dose of more than 55 Gy and/or a margin dose of more than 40 Gy. Serum adrenocorticotropic hormone and cortisol levels were normalized in 35% of patients, decreased significantly in 60%, and decreased in 85%. Fifty-one of 85 characteristic signs and symptoms of Cushing disease improved without any side effects. The overall outcome was excellent in seven cases, good in six, fair in four, and poor in four cases; one patient died. The initial treatment was GKS in four patients, two of whom had a complete response and two of whom had a partial response. Hormone levels returned to normal in the patients in whom there was a complete response. The results in the six patients in whom Nelson syndrome was present were less favorable; the response rate was only 33%, although the control rate was 100%. Hormone levels decreased in two patients.
Conclusions. Gamma knife radiosurgery is safe and effective for the treatment of Cushing disease as an adjuvant or initial therapy when selective and accurate dose planning is performed.
Effect of a single high-dose gamma irradiation on cultured cells in human cerebral arteriovenous malformation
Authors: Major Otto , Szeifert György T. , Fazekas Ilona , Vitanovics Dusan , Csonka Éva , Kocsis Béla , Bori Zoltán , Kemeny Andras A. , Nagy Zoltán 
Published: November 2018

Object. The purpose of this study was to analyze the effect of single high-dose gamma irradiation at a cellular biological level on tissue cultures obtained in patients who underwent surgery for cerebral arteriovenous malformation (AVM).
Methods. The cell proliferation indices and changes in activation of p53, p21Waf-1, and mdm-2 were determined. Additionally, immunohistochemical investigations for vimentin, desmin, α—smooth muscle actin (α-SMA), glial fibrillary acidic protein, Factor VIII—related antigen (F-VIII), cytokeratin, S100, and transforming growth factor—β (TGFβ) were performed on cultured AVM cells after a single high-dose irradiation. Normal human brain microvessel endothelial (HBE) cells and aortic smooth muscle cells served as controls.
The proliferation index decreased on the 5th day after irradiation and remained depressed over the observation period in the irradiated AVM cultures. The p53, p21Waf-1, and mdm-2 messenger RNA measurements showed considerable elevation both in AVM cultures and HBE cells after 15-Gy irradiation, which indicated apoptosis. Immunohistochemistry revealed strong vimentin positivity in the nonirradiated cultures, which gradually decreased in the irradiated cultures. Transforming growth factor—β positivity was demonstrated in the irradiated specimens, indicating transformation of fibroblastic cells into activated myofibroblastic elements. This transformation was confirmed by demonstrating elevated SMA expression as well in the radiation-treated fibroblasts.
Conclusions. The presence of TGFβ and α-SMA activity in the irradiated AVM cells suggests that along with the genetically confirmed apoptotic activity, fibroblast transformation into myofibroblasts might be one of the mechanisms leading to shrinkage and obliteration of AVMs after single high-dose gamma irradiation.
Can magnetic resonance imaging alone accurately define the arteriovenous nidus for gamma knife radiosurgery?
Authors: St. George E. J. , Butler P. , Plowman P. N. 
Published: November 2018

Object. Current radiosurgical treatment of arteriovenous malformations (AVMs) relies on planning protocols that integrate data from both magnetic resonance (MR) imaging and stereotactic angiography studies. Angiography, however, is invasive and associated with a small but well-defined risk of neurological and systemic complications. Magnetic resonance imaging, on the other hand, is noninvasive with multiplanar capability, demonstrates good anatomical detail, and has been shown to be superior to angiography in the delineation of selected AVMs.
Methods. In this study, MR imaging—related accuracy of defining the AVM nidus in gamma knife radiosurgery is investigated using only T1- and T2-weighted sequences.
Conclusions. Little interobserver variability was observed and AVM nidi, as demonstrated on T1- and T2-weighted MR images, were well correlated in terms of size. The displacement of the new target, however, from the original nidus, was not predictable and occasionally was significant, thus precluding safe radiosurgical planning.
Gamma knife radiosurgery for intracranial metastatic melanoma: a 6-year experience
Authors: Gonzalez-martinez Jorge , Hernandez Laura , Zamorano Lucia , Sloan Andrew , Levin Kenneth , Lo Simon , Li Qinghang , Diaz Fernando 
Published: November 2018

Object. The purpose of this study was to evaluate retrospectively the effectiveness of stereotactic radiosurgery for intracranial metastatic melanoma and to identify prognostic factors related to tumor control and survival that might be helpful in determining appropriate therapy.
Methods. Twenty-four patients with intracranial metastases (115 lesions) metastatic from melanoma underwent radiosurgery. In 14 patients (58.3%) whole-brain radiotherapy (WBRT) was performed, and in 12 (50%) chemotherapy was conducted before radiosurgery. The median tumor volume was 4 cm3 (range 1–15 cm3). The mean dose was 16.4 Gy (range 13–20 Gy) prescribed to the 50% isodose at the tumor margin. All cases were categorized according to the Recursive Partitioning Analysis classification for brain metastases. Univariate and multivariate analyses of survival were performed to determine significant prognostic factors affecting survival.
The mean survival was 5.5 months after radiosurgery. The analyses revealed no difference in terms of survival between patients who underwent WBRT or chemotherapy and those who did not. A significant difference (p < 0.05) in mean survival was observed between patients receiving immunotherapy or those with a Karnofsky Performance Scale (KPS) score of greater than 90.
Conclusions. The treatment with systemic immunotherapy and a KPS score greater than 90 were factors associated with a better prognosis. Radiosurgery for melanoma-related brain metastases appears to be an effective treatment associated with few complications.
The integration of metabolic imaging in stereotactic procedures including radiosurgery: a review
Authors: Levivier Marc , Wikler David , Massager Nicolas , David Philippe , Devriendt Daniel , Lorenzoni Jose , Pirotte Benoit , Desmedt Françoise , Simon Stephane , Goldman Serge , Van Houtte Paul , Brotchi Jacques 
Published: November 2018

Object. The authors review their experience with the clinical development and routine use of positron emission tomography (PET) during stereotactic procedures, including the use of PET-guided gamma knife radiosurgery (GKS).
Methods. Techniques have been developed for the routine use of stereotactic PET, and accumulated experience using PET-guided stereotactic procedures over the past 10 years includes more than 150 stereotactic biopsies, 43 neuronavigation procedures, and 34 cases treated with GKS. Positron emission tomography—guided GKS was performed in 24 patients with primary brain tumors (four pilocytic astrocytomas, five low-grade astrocytomas or oligodendrogliomas, seven anaplastic astrocytomas or ependymomas, five glioblastomas, and three neurocytomas), five patients with metastases (single or multiple lesions), and five patients with pituitary adenomas.
Conclusions. Data obtained with PET scanning can be integrated with GKS treatment planning, enabling access to metabolic information with high spatial accuracy. Positron emission tomography data can be successfully combined with magnetic resonance imaging data to provide specific information for defining the target volume for the radiosurgical treatment in patients with recurrent brain tumors, such as glioma, metastasis, and pituitary adenoma. This approach is particularly useful for optimizing target selection for infiltrating or ill-defined brain lesions. The use of PET scanning contributed data in 31 cases (93%) and information that was specifically utilized to adapt the target volume in 25 cases (74%). It would seem that the integration of PET data into GKS treatment planning may represent an important step toward further developments in radiosurgery: this approach provides additional information that may open new perspectives for the optimization of the treatment of brain tumors.
Experimentally determined three-dimensional dose distributions in small complex targets
Authors: Mack Andreas , Wolff Robert , Weltz Dirk , Mack Günther , Jess Anja , Heck Bernd , Czempiel Heinz , Kreiner Hans-Jürg , Wowra Berndt , Böttcher Heinz , Seiffert Volker 
Published: November 2018

Object. The purpose of the paper is to describe a workable three-dimensional dosimetry system for use in quality assurance programs of departments in which radiosurgery is performed.
Methods. A system was developed on the basis of radiochromatic films. The experimental findings of the measured dose distributions for small complex-shaped targets, within a specially designed phantom, are described and compared with the same parameters calculated from the corresponding dose plan. The following parameters were determined for 83 patients with irregularly shaped targets who underwent gamma knife radiosurgery (GKS): target volume; dose—volume histograms of the target; 12-Gy, 15-Gy, and 18-Gy volumes; dose plan conformity; dose fall profiles in all dimensions to 50% of the prescription dose; and a quality factor (QF) to evaluate the adequacy of a GKS plan or treatment.
The precise function and accuracy of the developed measuring device is shown and it demonstrated the expected steep dose falloff outside the irregularly shaped targets in all directions. The dose falloff was of the order of > 3 Gy/mm and the values of the QF were in the range between 0.5 and 0.9.
Conclusions. A comparison with data from the literature shows that at least for small targets (< 2 cm3 and < 2.5 cm3) simulated within a head phantom, the dose gradient is significantly steeper in all directions than when using alternative treatment devices in radiosurgery and the overall QF is superior in most of the cases.
Application of polymer gel dosimetry in gamma knife radiosurgery
Authors: Novotný Josef , Novotný Josef , Spĕvác˘ek Václav , Dvor˘ák Pavel , Cechák Tomás˘ , Lis˘c˘ák Roman , Broz˘ek Gustav , Tintĕra Jaroslav , Vymazal Josef 
Published: November 2018

Object. The purpose of this study was to investigate the use of a polymer gel—based dosimeter for the evaluation of geometric and dosimetric inaccuracies during gamma knife radiosurgery and during the irradiation of an experimental animal.
Methods. A polymer gel dosimeter, based on acrylic monomers, was used for experiments conducted in this study. The accuracy of the dosimeter was evaluated on a Siemens EXPERT 1-tesla scanner in the transmitter/receiver head coil with the use of a multiecho sequence with 16 echoes, TE 22.5 to 360 msec, TR 2000 msec, slice thickness 2 mm, field of view 255 mm, and a pixel size of 0.5 × 0.5 mm2. Two experiments were conducted. First, the head phantom containing the polymer gel dosimeter was irradiated using 4-, 8-, 14-, and 18-mm isocenters. Second, a specially designed rat phantom was irradiated by four 4-mm isocenters. The dose profiles in the x, y, and z axes were calculated in the treatment planning system and measured with the polymer gel dosimeter and the results were compared.
There was good agreement between the measured and calculated dose profiles. The maximum deviation in the spatial position of the center of measured and calculated dose profiles was 0.5 mm in the head phantom and 1 mm in the rat phantom. The maximum deviation in the width of the selected reference isodose of measured profiles was 1.2 mm in the head phantom and 1.1 mm in the rat phantom.
Conclusions. The use of the polymer gel—based dosimeter for the verification of stereotactic procedures has advantages compared with other dosimetric systems. The dosimeter itself is tissue equivalent. Three-dimensional dose distributions can be measured and the dosimeter allows simulation of the therapeutic procedures.
Rotational movements of the Automatic Positioning System under load and their significance for patient treatments
Authors: Walton Lee , Hampshire Anna , Brownett Christopher , Soanes Tracy , Vaughan Paul , Rowe Jeremy , Radatz Matthias , Kemeny Andras 
Published: November 2018

Object. During routine quality assurance (QA) testing of the gamma knife Automatic Positioning System (APS), it was noticed that slight pressure applied to the handle of the QA test tool produced visible rotation of the APS assembly. The authors describe the tests performed to quantify these movements.
Methods. A stereotactic frame was positioned in the slides of the APS and known loads applied using a spring balance to the upper corner of the frame. Movement at the corner of the frame (y = 200) was measured using a dial gauge. The typical load applied to the APS by a patient with a medium-sized head was determined in a treatment simulation. Projecting the measured data, a plot showing the resultant error in the position of a target point was constructed. Error values increased with distance from the frame, up to a maximum of 0.3 mm (at the superior limit of treatment range). Increased loads could be applied to the system during patient movements, and these would result in larger displacements. Two volunteers enlisted to simulate patient movements and the deflections were recorded. It was estimated that maximum errors in the target positioning of 0.45 mm might take place during these movements.
Conclusions. The use of the APS has some additional and unexpected associated errors. The authors believe, however, that because the errors are smaller than those of target localization and manual trunnion treatments, its clinical use is still justified. The manufacturer is investigating the cause of the movements and possible solutions.
Gamma knife radiosurgery for craniopharyngiomas: longterm results in the first Swedish patients
Authors: Úlfarsson Elfar , Lindquist Christer , Roberts Maud , Rähn Tiit , Lindquist Melker , Thorén Marja , Lippitz Bodo 
Published: November 2018

Object. The purpose of this study was to assess the long-term treatment efficacy and morbidity of patients who undergo gamma knife radiosurgery (GKS) for craniopharyngioma.
Methods. Twenty-one consecutive Swedish patients were evaluated retrospectively: 11 children (≤ 15 years) and 10 adults. The time from diagnosis to the most recent follow-up imaging study was 6.3 to 34.3 years (mean 18.2 years, median 16.8 years). Tumor volumes and morbidity from GKS or other treatments were assessed at the time of the most recent imaging study or at the time of a subsequent new treatment. The observation period ranged from 0.5 to 29 years (mean 7.5 years, median 3.5 years). The prescription dose ranged from less than 3 Gy to 25 Gy. The mean tumor volume was 7.8 cm3 (range 0.4–33 cm3).
There were 22 tumors in 21 patients treated with GKS. Five of these tumors were reduced in size, three were unchanged, and 14 increased. Tumor progression correlated with a low dose to the tumor margin. Eleven (85%) of 13 tumors that received a dose of less than 6 Gy to the margin increased in size, whereas only three (33%) of nine tumors that received 6 Gy increased. This difference was statistically significant (p = 0.01). In five of six patients tumors that became smaller after GKS there were no recurrences within a mean follow-up period of 12 years. Nine (82%) of 11 tumors in children ultimately increased after GKS, compared with five (50%) of 10 in adults. In eight patients there was a deterioration of visual function. In all except one this could be related to a volume increase but radiation-induced damage could not be excluded as a factor in any of them. Four patients developed pituitary deficiencies.
Conclusions. Gamma knife radiosurgery is effective in controlling growth of craniopharyngiomas with a minimum dose of 6 Gy. The findings also suggest that other stereotactic techniques, such as cyst aspiration and intracystic treatment, are only of value in reducing tumor volume in preparation for safe GKS.
Gamma knife radiosurgery in patients with advanced breast cancer undergoing bone marrow transplant
Authors: Levin Kenneth J. , Youssef Emad F. , Sloan Andrew E. , Patel Rajiv , Zabad Rana K. , Zamorano Lucia 
Published: November 2018

Object. Recent studies have suggested a high incidence of cognitive deficits in patients undergoing high-dose chemotherapy, which appears to be dose related. Whole-brain radiotherapy (WBRT) has previously been associated with cognitive impairment. The authors attempted to use gamma knife radiosurgery (GKS) to delay or avoid WBRT in patients with advanced breast cancer treated with high-dose chemotherapy and autologous bone marrow transplantation (HDC/ABMT) in whom brain metastases were diagnosed.
Methods. A retrospective review of our experience from 1996 to 2001 was performed to identify patients who underwent HDC/ABMT for advanced breast cancer and brain metastasis. They were able to conduct GKS as initial management to avoid or delay WBRT in 12 patients following HDC/ABMT. All patients were women. The median age was 48 years (range 30–58 years). The Karnofsky Performance Scale score was 70 (range 60–90). All lesions were treated with a median prescription dose of 17 Gy (range 15–18 Gy) prescribed to the 50% isodose.
Median survival was 11.5 months. Five patients (42%) had no evidence of central nervous system disease progression and no further treatment was given. Four patients were retreated with GKS and three of them eventually received WBRT as well. Two patients were treated with WBRT as the primary salvage therapy. The median time to retreatment with WBRT was 8 months after the initial GKS.
Conclusions. Gamma knife radiosurgery can be effectively used for the initial management of brain metastases to avoid or delay WBRT in patients treated previously with HDC, with acceptable survival and preserved cognitive function.