bluuebunny/crossref_metadata_2025_split huggingface dataset:
The commissioning and quality assurance of the Automatic Positioning System on the Leksell gamma knife
Authors: Soanes Tracy , Hampshire Anna , Vaughan Paul , Brownett Christopher , Rowe Jeremy , Radatz Matthias , Kemeny Andras , Walton Lee 
Published: November 2018

Object. The authors describe a series of commissioning checks that were developed following the installation of the Automatic Positioning System (APS) on the model C gamma knife.
Methods. System reliability was checked by performing a series of test treatments using the APS. A phantom was designed to enable the exposure of small pieces of Gaf Chromic film at 40 different predefined x, y, and z coordinates. The phantom consisted of a base plate with a series of film holders to facilitate the exposures using a 4-mm field, the center of which was marked.
A spreadsheet calculation was performed to verify the conversion from Leksell coordinates to the APS coordinates when the treatment angle (gamma angle) is other than 90°. A number of APS plans were prepared and the coordinate transformation verified.
Precision measurements were performed to verify the correct positioning of the high bars when attached to the frame. The Gaf Chromic films were exposed, and the APS plans were used when confined to positions within the high bar range. A test tool to verify accurate location of the high bars on the frame was also designed.
Conclusions. The performance of APS was verified independently of the manufacturer by using specially designed tools, phantoms, and spread sheets. At all points tested, the positional accuracy was found to be within specification. Conversion to APS coordinates was verified as correct.
Multimodal management of craniopharyngiomas: neuroendoscopy, microsurgery, and radiosurgery
Authors: Barajas Marco A. , Ramírez-Guzmán Guadalupe , Rodríguez-Vázquez Carlos , Toledo-Buenrostro Vinicio , Velásquez-Santana Héctor , Robles Ramiro del Valle , Cuevas-Solórzano Abel , Rodríguez-Hernández Gabriel 
Published: November 2018

Object. The goal of this study was to examine the role of gamma knife radiosurgery (GKS) and adjuvant neuroendoscopic procedures by assessing the outcome in 10 patients with craniopharyngiomas who were treated between 1998 and 2001.
Methods. In 10 consecutive patients (six males and four females, mean age 12 years [range 7–32 years]), there were nine mixed and one solid craniopharyngioma. In the last three cases, neuroendoscopic procedures were conducted. Two cases required insertion of an Ommaya reservoir. In another case partial removal of the cyst wall was performed using an endoscope to create a communication with the cerebrospinal pathways and thereby preclude the need for shunt insertion.
Conclusions. Multimodal management of craniopharyngiomas seems to provide a better rate of survival and greater long-term disease control. It is suggested that GKS combined with adjuvant neuroendoscopy should be used as an alternative in treating recurrent or residual craniopharyngiomas if additional microsurgical removal cannot guarantee a cure.
Observations of intracranial neoplasms treated with gamma knife radiosurgery
Authors: Szeifert György T. , Massager Nicolas , DeVriendt Daniel , David Philippe , De Smedt Françoise , Rorive Sandrine , Salmon Isabelle , Brotchi Jacques , Levivier Marc 
Published: November 2018

Object. The purpose of this study was to compare histopathological changes with imaging findings in different tumors after gamma knife radiosurgery (GKS).
Methods. Five patients of a series of 220 treated with GKS underwent craniotomy for tumor removal 3 to 12 months after radiosurgery. There were two patients with multiple cerebral metastases, one with vestibular schwannoma, one with malignant glioma, and one with meningioma. A portion of normal brain tissue outside the prescription dose volume was acquired wherever possible to facilitate examination of the effects of radiosurgery. Histopathological and immunohistochemical investigations were performed. In addition to the routine hematoxylin and eosin and Mallory trichrome stains, immunohistochemical reactions were also performed for Factor VIII—associated antigen (FVIII) and CD34 antigen to study vascular endothelial effects of the irradiation.
Endothelial cells of vessels in the normal brain tissue covering the tumor, outside of the prescription isodose volume, expressed marked CD34 and FVIII positivity. In the irradiated targeted tumor tissue samples, however, both reactions decreased remarkably.
Conclusions. The results of the present immunohistochemical study provide support to the experimental hypothesis that vascular endothelial cells are the principal targets of single high-dose irradiation. The loss of central contrast enhancement of tumor tissue following radiosurgery might be consequence of the vascular damage.
Retrospective analysis of unstaged and staged Gamma Knife surgery with and without preceding embolization for the treatment of arteriovenous malformations
Authors: Back Adam G. , Vollmer Dennis , Zeck Otto , Shkedy Clive , Shedden Peter M. 
Published: November 2018

Object
The authors conducted a retrospective study to examine data on rates of obliteration of arteriovenous malformations (AVMs) with use of various combinations of treatment modalities based on Gamma Knife surgery (GKS). The authors believe that this study is the first to report on patients treated with embolization followed by staged GKS.

Methods
The authors identified 150 patients who underwent GKS for treatment of AVMs between 1994 and 2004. In a retrospective study, 4 independent groups emerged based on the various combinations of treatment: 92 patients who underwent unstaged GKS, 28 patients who underwent embolization followed by unstaged GKS, 23 patients who underwent staged GKS, and 7 patients who underwent embolization followed by staged GKS. A minimum of 3 years of follow-up after the last GKS treatment was required for inclusion in the retrospective analysis. Angiograms, MR images, or CT scans at follow-up were required for calculating rates of obliteration of AVMs.

Results
Fifty-seven of 150 patients (38%) supplied angiograms, and overall obliteration was confirmed in 43 of these 57 patients (75.4%). An additional 37 patients had follow-up MR images or CT scans. The overall obliteration rate, including patients with follow-up angiograms and patients with follow-up MR images or CT scans, was 68 of 94 (72.3%). Patients who underwent unstaged GKS had a follow-up rate of 58.7% (54 of 92) and an obliteration rate of 75.9% (41 of 54). Patients who underwent embolization followed by unstaged GKS had a follow-up rate of 53.5% (15 of 28) and an obliteration rate of 60.0% (9 of 15). Patients who underwent staged GKS had a follow-up rate of 82.6% (19 of 23) and an obliteration rate of 73.7% (14 of 19). Patients who underwent embolization followed by staged GKS had a follow-up rate of 85.7% (6 of 7) and an obliteration rate of 66.7% (4 of 6).

Conclusions
Gamma Knife surgery is an effective means of treating AVMs. Embolization prior to GKS may reduce AVM obliteration rates. Staged GKS is a promising method for obtaining high obliteration rates when treating larger AVMs in eloquent locations.
Gamma Knife surgery for the treatment of melanoma metastases: the effect of intratumoral hemorrhage on survival
Authors: Redmond Andy J. , DiLuna Michael L. , Hebert Ryan , Moliterno Jennifer A. , Desai Rani , Knisely Jonathan P. S. , Chiang Veronica L. 
Published: November 2018

Object
Gamma Knife surgery (GKS) improves overall survival in patients with malignant melanoma metastatic to the brain. In this study the authors investigated which patient- or treatment-specific factors influence survival of patients with melanoma brain metastases; they pay particular interest to pre- and post-GKS hemorrhage.

Methods
Demographic, treatment, and survival data on 59 patients with a total of 208 intracranial metastases who underwent GKS between 1998 and 2007 were abstracted from treatment records and from the Connecticut Tumor Registry. Multivariate analysis was used to identify factors that independently affected survival.

Results
Survival was significantly better in patients with solitary metastasis (p = 0.04), lesions without evidence of pre-GKS hemorrhage (p = 0.004), and in patients with total tumor volume treated < 4 cm3 (p = 0.02). Intratumoral bleeding occurred in 23.7% of patients pre-GKS. Intratumoral bleeding occurred at a mean of 1.8 months post-GKS at a rate of 15.2%. Unlike the marked effect of pretreatment bleeding, posttreatment bleeding did not independently affect survival. Sex, systemic control, race, metastases location, whole-brain radiation therapy, chemotherapy, history of antithrombotic medications, and cranial surgery had no independent association with survival.

Conclusions
These data corroborate previous findings that tumor burden (either as increased number or total volume of lesions) at the time of GKS is associated with diminished patient survival in those with intracerebral melanoma metastases. Patients who were noted to have hemorrhagic melanoma metastases prior to GKS appear to have a worse prognosis following GKS compared with patients with nonhemorrhagic metastases, despite similar rates of bleeding pre- and post-GKS treatment. Gamma Knife surgery itself does not appear to increase the rate of hemorrhage.
Gamma Knife surgery for schwannomas originating from cranial nerves III, IV, and VI
Authors: Kim In-Young , Kondziolka Douglas , Niranjan Ajay , Flickinger John C. , Lunsford L. Dade 
Published: November 2018

Object
Schwannomas from the motor cranial nerves controlling eye movement are rare. The authors evaluated the role of Gamma Knife surgery (GKS) in the management of schwannomas originating from cranial nerves III, IV, and VI.

Methods
Over a 7-year period, 8 patients with schwannomas originating from the oculomotor (2 patients), trochlear (5 patients), or abducent (1) nerve underwent GKS. The mean patient age was 46.1 years (range 19–59 years). The presenting symptoms included diplopia in 5 patients, ptosis in 1 patient, ophthalmoplegia in 1 patient, and headache in 1 patient. Two patients had a history of neurofibromatosis Type 2. Gamma Knife surgery was performed as primary management in 7 patients and after prior resection in 1 patient. The median and mean tumor volumes were 0.22 and 1.32 cm3 (range 0.03–7.4 cm3). A median margin dose of 12.5 Gy (range 11.0–13.0 Gy) was prescribed to the tumor margin. Clinical and imaging follow-up data were available for all 8 patients.

Results
Magnetic resonance imaging showed tumor regression in all patients. The progression-free period varied from 4 to 42 months, with a mean of 21 months. Over a mean of 23 months, 4 of the 5 patients with a trochlear schwannoma and symptoms of diplopia noted symptomatic improvement. No improvement was noted in the 2 patients with oculomotor nerve palsies. Headache was improved in the 1 patient with an abducent neuroma.

Conclusions
Gamma Knife surgery is an effective and minimally invasive approach capable of inactivating schwannomas originating from the oculomotor, trochlear, and abducent nerves. Accompanying trochlear function may improve. Longer follow-up and larger patient samples are needed to confirm the authors' initial observations.
Comparison of the results of 2 targeting methods in Gamma Knife surgery for trigeminal neuralgia
Authors: Matsuda Shinji , Serizawa Toru , Nagano Osamu , Ono Junichi 
Published: November 2018

Object
Gamma Knife surgery (GKS) is an effective treatment for intractable trigeminal neuralgia (TN). The authors compared results using two major GKS target points, the dorsal root entry zone and the retrogasserian portion, in a series of patients with intractable TN.

Methods
One hundred patients with medically refractory TN underwent GKS between August 1998 and December 2007. Thirty-seven were men, and 63 were women. The median age at GKS was 74 years. With a single isocenter and use of a 4mm collimator, 51 patients received 80 Gy at the proximal trigeminal nerve (posterior group) and 7 patients received 80 Gy, 1 patient received 85 Gy, and 41 patients received 90 Gy at the retrogasserian portion (anterior group). Follow-up was obtained by clinic visits every 3–6 months after GKS. Data on pain control, complications, and pain recurrence were recorded. The relationships between pain control status, complications, recurrence, and the target portions (anterior vs posterior) were analyzed.

Results
The median duration of follow-up was 30 months (range 3–88 months). Initially, 87 patients achieved pain-free status and 64 achieved complete remission. At the final follow-up visit, 68 patients were still in pain-free status and 42 were in complete remission. Recurrence of facial pain occurred in 15 patients. Forty-one patients developed some degree of trigeminal dysfunction. The rate of initial complete remission was higher in the posterior group than in the anterior group (p = 0.003). More complications were observed in the anterior group than in the posterior group (p = 0.009).

Conclusions
The posterior targeting group had better pain control and a lower complication rate. The authors recommend the posterior targeting method and use of 80 Gy for treatment of TN with GKS.
Definition of the key target volume in radiosurgical management of arteriovenous malformations: a new dynamic concept based on angiographic circulation time
Authors: Valle Ramiro Del , Zenteno Marco , Jaramillo José , Lee Angel , De Anda Salvador 
Published: November 2018

Object
The cumulative experience worldwide indicates complete radiosurgical obliteration rates of brain arteriovenous malformations (AVMs) ranging from 35 to 90%. The purpose of this study was to propose a strategy to increase the obliteration rate for AVMs through the dynamic definition of the key target volume (KTV).

Methods
A prospective series of patients harboring an AVM was assessed using digital subtraction angiography in which a digital counter was used to measure the several stages of the frame-by-frame circulation time. All the patients were analyzed using dynamic measurement planning to define the KTV, corresponding to the volume of the shunt with the least vascular resistance and the earliest venous drainage. All patients underwent catheter-based angiography, a subgroup was additionally assessed by means of a superselective catheterization, and among these a further subgroup received embolization. The shunts were also categorized according to their angioarchitectural type: fistulous, plexiform, or mixed. The authors applied the radiosurgery-based grading system (RBGS) as well to find a correlation with the obliteration rate.

Results
This series includes 44 patients treated by radiosurgery; global angiography was performed for all patients, including dynamic measurement planning. Eighty-four percent of them underwent superselective catheterization, and 50% of the total population underwent embolization. In the embolized arm of the study, the pretreatment volume was up to 120 ml. In patients with a single treatment, the mean volume was 8.5 ml, and the median volume was 6.95 ± 4.56 ml (mean ± standard deviation), with a KTV of up to 15 ml. For prospectively staged radiosurgery, the mean KTV was 28 ml. The marginal radiation dose was 18–22 Gy, with a mean of dose 20 Gy. The mean RBGS score was 1.70. The overall obliteration rate was 91%, including the repeated radiosurgery group (4 patients), in which 100% showed complete obliteration. The overall permanent deficit was 2 of 44 patients, 1 in each group.

Conclusions
Dynamic definition of the KTV might increase the obliteration rate, even in complex AVMs, allowing the treatment of smaller volumes off the recruitment vessels (pseudonidus). By using this technique, the authors avoided double-blind treatment, where the neurosurgeon does not know precisely which type of lesion he or she is irradiating and the interventionalist does not know why and what he or she is embolizing.
Age and outcome following traumatic coma: why do older patients fare worse?
Authors: Vollmer Dennis G. , Torner James C. , Jane John A. , Sadovnic Barbara , Charlebois Deborah , Eisenberg Howard M. , Foulkes Mary A. , Marmarou Anthony , Marshall Lawrence F. 
Published: November 2018

✓ To better understand the relationship between patient age and clinical outcome following traumatic coma, the data for 661 patients, aged 15 years or older at the time of receiving a nonpenetrating head injury, were analyzed. All patients were prospectively followed and the information was entered into the Traumatic Coma Data Bank. This information was statistically analyzed to determine trends and interactions between patient age and other prognostic indicators. Older patients had higher rates of mortality overall; vegetative survival was seen in 4.8% to 8.0% of patients and did not exhibit a trend related to age. Injury severity, as assessed by motor score or Glasgow Coma Scale score, did not significantly differ according to age. The injury mechanism was age-related, with a greater frequency of falls and pedestrian accidents in older patients. Multiple injury was less frequent in older patients. Medical complications and systemic trauma were considered to be the primary cause of death in less than 25% of patients, with the exception of those between 45 and 55 years of age. When the data were studied in univariate fashion, no factor was identified that accounts for the adverse effect of age on head-injury outcome.
Multivariate logistic regression, performed to assess the combined effect of multiple variables on outcome, failed to eliminate patient age as an independent predictor. Based upon this analysis, it is likely that the effect of age on outcome following head injury is dependent upon an alteration in the pathophysiological response of the aging central nervous system to severe trauma and not an increased incidence of non-neurological complications or other clinical parameters.
Long-term results of gamma knife surgery for growth hormone—producing pituitary adenoma: is the disease difficult to cure?
Authors: Kobayashi Tatsuya , Mori Yoshimasa , Uchiyama Yukio , Kida Yoshihisa , Fujitani Shigeru 
Published: November 2018

Object. The authors conducted a study to determine the long-term results of gamma knife surgery for residual or recurrent growth hormine (GH)—producing pituitary adenomas and to compare the results with those after treatment of other pituitary adenomas.
Methods. The series consisted of 67 patients. The mean tumor diameter was 19.2 mm and volume was 5.4 cm3. The mean maximum dose was 35.3 Gy and the mean margin dose was 18.9 Gy. The mean follow-up duration was 63.3 months (range 13–142 months).
The tumor resolution rate was 2%, the response rate 68.3%, and the control rate 100%. Growth hormone normalization (GH < 1.0 ng/ml) was found in 4.8%, nearly normal (< 2.0 ng/ml) in 11.9%, significantly decreased (< 5.0 ng/ml) in 23.8%, decreased in 21.4%, unchanged in 21.4%, and increased in 16.7%. Serum insulin-like growth factor (IGF)—1 was significantly decreased (IGF-1 < 400 ng/ml) in 40.7%, decreased in 29.6%, unchanged in 18.5%, and increased in 11.1%, which was almost parallel to the GH changes.
Conclusions. Gamma knife surgery was effective and safe for the control of tumors; however, normalization of GH and IGF-1 secretion was difficult to achieve in cases with large tumors and low-dose radiation. Gamma knife radiosurgery is thus indicated for small tumors after surgery or medication therapy when a relatively high-dose radiation is required.
Radiosurgery of vestibular schwannomas: summary of experience in 829 cases
Authors: Lunsford L. Dade , Niranjan Ajay , Flickinger John C. , Maitz Ann , Kondziolka Douglas 
Published: November 2018

Object. Management options for vestibular schwannomas (VSs) have greatly expanded since the introduction of stereotactic radiosurgery. Optimal outcomes reflect long-term tumor control, preservation of cranial nerve function, and retention of quality of life. The authors review their 15-year experience.
Methods. Between 1987 and 2002, some 829 patients with VSs underwent gamma knife surgery (GKS). Dose selection, imaging, and dose planning techniques evolved between 1987 and 1992 but thereafter remained stable for 10 years. The average tumor volume was 2.5 cm3. The median margin dose to the tumor was 13 Gy (range 10–20 Gy).
No patient sustained significant perioperative morbidity. The average duration of hospital stay was less than 1 day. Unchanged hearing preservation was possible in 50 to 77% of patients (up to 90% in those with intracanalicular tumors). Facial neuropathy risks were reduced to less than 1%. Trigeminal symptoms were detected in less than 3% of patients whose tumors reached the level of the trigeminal nerve. Tumor control rates at 10 years were 97% (no additional treatment needed).
Conclusions. Superior imaging, multiple isocenter volumetric conformal dose planning, and optimal precision and dose delivery contributed to the long-term success of GKS, including in those patients in whom initial microsurgery had failed. Gamma knife surgery provides a low risk, minimally invasive treatment option for patients with newly diagnosed or residual VS. Cranial nerve preservation and quality of life maintenance are possible in long-term follow up.
Gamma knife surgery for glomus jugulare tumors: an intermediate report on efficacy and safety
Authors: Sheehan Jason , Kondziolka Douglas , Flickinger John , Lunsford L. Dade 
Published: November 2018

Object. Glomus jugulare tumors are rare tumors that commonly involve the middle ear, temporal bone, and lower cranial nerves. Resection, embolization, and radiation therapy have been the mainstays of treatment. Despite these therapies, tumor control can be difficult to achieve particularly without undo risk of patient morbidity or mortality. The authors examine the safety and efficacy of gamma knife surgery (GKS) for glomus jugulare tumors.
Methods. A retrospective review was undertaken of the results obtained in eight patients who underwent GKS for recurrent, residual, or unresectable glomus jugulare tumors. The median radiosurgical dose to the tumor margin was 15 Gy (range 12–18 Gy). The median clinical follow-up period was 28 months, and the median period for radiological follow up was 32 months.
All eight patients demonstrated neurological stability or improvement. No cranial nerve palsies arose or deteriorated after GKS. In the seven patients in whom radiographic follow up was obtained, the tumor size decreased in four and remained stable in three.
Conclusions. Gamma knife surgery would seem to afford effective local tumor control and preserves neurological function in patients with glomus jugulare tumors. If long-term results with GKS are equally efficacious, the role of stereotactic radiosurgery will expand.