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John C. Flickinger - One of the best experts on this subject based on the ideXlab platform.
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a modified Radiosurgery based arteriovenous malformation grading scale and its correlation with outcomes
International Journal of Radiation Oncology Biology Physics, 2011Co-Authors: Rodney E Wegner, Bruce E. Pollock, Dade L Lunsford, Douglas Kondziolka, Ajay Niranjan, Kaan Oysul, Sait Sirin, John C. FlickingerAbstract:Purpose The Pittsburgh Radiosurgery-based arteriovenous malformation (AVM) grading scale was developed to predict patient outcomes after Radiosurgery and was later modified with location as a two-tiered variable (deep vs. other). The purpose of this study was to test the modified Radiosurgery-based AVM score in a separate set of AVM patients managed with Radiosurgery. Methods and Materials The AVM score is calculated as follows: AVM score=(0.1)(volume, cc) + (0.02)(age, years) + (0.5)(location; frontal/temporal/parietal/occipital/intraventricular/corpus callosum/cerebellar = 0, basal ganglia/thalamus/brainstem = 1). Testing of the modified system was performed on 293 patients having AVM Radiosurgery from 1992 to 2004 at the University of Pittsburgh with dose planning based on a combination of stereotactic angiography and MRI. The median patient age was 38 years, the median AVM volume was 3.3 cc, and 57 patients (19%) had deep AVMs. The median modified AVM score was 1.25. The median patient follow-up was 39 months. Results The modified AVM scale correlated with the percentage of patients with AVM obliteration without new deficits (≤1.00, 62%; 1.01–1.50, 51%; 1.51–2.00, 53%; and >2.00, 32%; F = 11.002, R 2 = 0.8117, p = 0.001). Linear regression also showed a statistically significant correlation between outcome and dose prescribed to the margin ( F = 25.815, p Conclusions The modified Radiosurgery-based AVM grading scale using location as a two-tiered variable correlated with outcomes when tested on a cohort of patients who underwent both angiography and MRI for dose planning. This system can be used to guide choices among observation, endovascular, surgical, and radiosurgical management strategies for individual AVM patients.
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modification of the Radiosurgery based arteriovenous malformation grading system
Neurosurgery, 2008Co-Authors: Bruce E. Pollock, John C. FlickingerAbstract:OBJECTIVE: The Radiosurgery-based arteriovenous malformation (AVM) grading scale was developed to predict patient outcomes after Radiosurgery. The purpose of this study was to determine whether simplifying this grading system using location as a two-tiered variable detracted from the accuracy of the scale. METHODS: Regression analysis modeling on 220 patients who underwentAVM Radiosurgery between 1987 and 1992 at the University of Pittsburgh Medical Center using location as a two-tiered variable resulted in the following equation: AVM score = (0.1) (volume, mL) + (0.02) (age, yr) + (0.3) (location, hemispheric/corpus callosum/cerebellar = 0; basal ganglia/thalamus/brainstem = 1). Testing of the modified grading system was performed on 247 patients who underwent AVM Radiosurgery between 1990 and 2001 at the Mayo Clinic. The mean modified AVM score was 1.62. The mean duration of patient follow-up was 70 months. RESULTS: There was no difference between the original and modified Radiosurgery-based AVM scale with regard to AVM obliteration without new neurological deficits (F = 0.92, P = 0.53) or decline in Modified Rankin Scale (F= 0.83, P = 0.56) after radio-surgery. The modified Radiosurgery-based AVM scale correlated with the percentage of patients with AVM obliteration without new deficits (= ≤ 1.00, 89%; 1.01-1.50, 70%; 1.51-2.00, 64%; ≥2.00, 46%) (r = -0.98, P 2.00, 36%) (r= 0.99, P < 0.01). CONCLUSION: Simplifying the Radiosurgery-based AVM grading system using location as a two-tiered variable did not detract from the accuracy of the scale. This system has been validated by numerous centers performing both gamma knife- and linear accelerator-based procedures and should be used in future studies on AVM Radiosurgery to stratify patients for more accurate comparative analyses.
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cranial nerve preservation and outcomes after stereotactic Radiosurgery for jugular foramen schwannomas
Neurosurgery, 2007Co-Authors: Juan J Martin, David Mathieu, Douglas Kondziolka, John C. Flickinger, Ajay Niranjan, Dade L LunsfordAbstract:OBJECTIVE: Jugular foramen region schwannomas are rare intracranial tumors that usually present with multiple lower cranial nerve deficits. For some patients, complete surgical resection is possible but may be associated with significant morbidity. Stereotactic Radiosurgery is a minimally invasive alternative or adjunct to microsurgery for such tumors. We reviewed our clinical and imaging outcomes after patients underwent gamma knife Radiosurgery for management of jugular foramen schwannomas. METHODS: Thirty-four patients with 35 tumors (one patient had bilateral tumors) underwent Radiosurgery between May 1990 and December 2005. Twenty-two patients had previous microsurgical resection and all patients experienced various cranial neuropathies. A median of six isocenters were used. Median marginal and maximum doses were 14 and 28 Gy, respectively. RESULTS: None of the patients were lost to evaluation and the mean duration of follow-up was 83 months. Tumors regressed in 17 patients, remained stable in 16, and progressed in two. Five- and 10-year actuarial control rates were 97 and 94%, respectively. Preexisting cranial neuropathies improved in 20% and remained stable in 77% after Radiosurgery. One patient worsened. The function of all previous intact nerves was preserved after Radiosurgery. CONCLUSION: Stereotactic Radiosurgery proved to be a safe and effective management for newly diagnosed or residual jugular foramen schwannomas. Long-term tumor control rates and stability or improvement in cranial nerve function was confirmed.
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recursive partitioning analysis of prognostic factors for patients with four or more intracranial metastases treated with Radiosurgery
Technology in Cancer Research & Treatment, 2007Co-Authors: Ajay Bhatnagar, Dade L Lunsford, Douglas Kondziolka, John C. FlickingerAbstract:The purpose of this study was to devise a new recursive partitioning analysis (RPA) of patients with four or more intracranial metastases treated with a single Radiosurgery procedure to identify a class of patients with extended survival. 205 patients underwent Gamma Knife Radiosurgery for four or more intracranial metastases (median = 5, range 4–18) during one session. The median total treatment volume was 6.8 cc (range 0.6–51.0 cc). Radiosurgery was used as sole management (17% of patients), or in combination with WB-RT (46%), or after failure of WB-RT (38%). The median marginal Radiosurgery dose was 16 Gy (range 12–20 Gy). RPA assessed the effects of age, Karnofsky >70, extracranial disease, visceral metastases, number of metastases, total treatment volume, history of breast and melanoma primaries on survival. The median overall survival after Radiosurgery for all patients was 8 months. RPA identified a favorable subgroup of 78 patients (43% of the series) with a total treatment volume <7 cc and < 7 br...
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stereotactic Radiosurgery for vestibular schwannomas in patients with neurofibromatosis type 2 an analysis of tumor control complications and hearing preservation rates
Neurosurgery, 2007Co-Authors: David Mathieu, Douglas Kondziolka, John C. Flickinger, Ajay Niranjan, Richard W Williamson, Juan J Martin, Dade L LunsfordAbstract:OBJECTIVE: Vestibular schwannomas present significant management challenges in patients with neurofibromatosis Type 2 (NF2). We evaluated the results of gamma knife Radiosurgery for the management of these tumors, focusing on tumor response, hearing preservation, and other factors affecting outcomes. METHODS: Stereotactic Radiosurgery was performed to manage 74 schwannomas in 62 patients. Ipsilateral serviceable hearing was present in 35% of tumors before the procedure. The mean tumor volume was 5.7 cm3. The mean margin and maximum dose used were 14 and 27.5 Gy, respectively. Cox regression analyses were performed to to identify factors affecting outcomes. RESULTS: The median follow-up period was 53 months, and two patients were lost to follow-up. Actuarial local control rates at were 85, 81, and 81 % at 5, 10, and 15 years, respectively. Tumor volume was significant as a predictor of local control. Since 1992, using current Radiosurgery techniques (magnetic resonance imaging scan targeting and reduced margin dose to 14 Gy or less), the actuarial serviceable hearing preservation rate is 73% at 1 year, 59% at 2 years, and 48% at 5 years after Radiosurgery. Facial neuropathy occurred in 8% of tumors, trigeminal neuropathy occurred in 4%, and vestibular dysfunction occurred in 4%. Radiation dose and tumor volume were predictive of development of new deficits. No Radiosurgery-associated secondary tumors or atypical or malignant changes were noted. CONCLUSION: Stereotactic Radiosurgery is a safe and effective management modality for neurofibromatosis Type 2 vestibular schwannomas. Although results do not seem to be as good as for patients with sporadic unilateral tumors, gamma knife Radiosurgery results seem favorable and indicate that Radiosurgery should be strongly considered for primary tumor management in selected patients.
Douglas Kondziolka - One of the best experts on this subject based on the ideXlab platform.
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gamma knife surgery for the management of glomus tumors a multicenter study
Journal of Neurosurgery, 2012Co-Authors: Jason P Sheehan, David Mathieu, Bruce E. Pollock, Douglas Kondziolka, Michael J Link, Anthony M Kaufmann, Shota Tanaka, Christopher Duma, Byron A Young, Heyoung McbrideAbstract:Object Glomus tumors are rare skull base neoplasms that frequently involve critical cerebrovascular structures and lower cranial nerves. Complete resection is often difficult and may increase cranial nerve deficits. Stereotactic Radiosurgery has gained an increasing role in the management of glomus tumors. The authors of this study examine the outcomes after Radiosurgery in a large, multicenter patient population. Methods Under the auspices of the North American Gamma Knife Consortium, 8 Gamma Knife surgery centers that treat glomus tumors combined their outcome data retrospectively. One hundred thirty-four patient procedures were included in the study (134 procedures in 132 patients, with each procedure being analyzed separately). Prior resection was performed in 51 patients, and prior fractionated external beam radiotherapy was performed in 6 patients. The patients' median age at the time of Radiosurgery was 59 years. Forty percent had pulsatile tinnitus at the time of Radiosurgery. The median dose to t...
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a modified Radiosurgery based arteriovenous malformation grading scale and its correlation with outcomes
International Journal of Radiation Oncology Biology Physics, 2011Co-Authors: Rodney E Wegner, Bruce E. Pollock, Dade L Lunsford, Douglas Kondziolka, Ajay Niranjan, Kaan Oysul, Sait Sirin, John C. FlickingerAbstract:Purpose The Pittsburgh Radiosurgery-based arteriovenous malformation (AVM) grading scale was developed to predict patient outcomes after Radiosurgery and was later modified with location as a two-tiered variable (deep vs. other). The purpose of this study was to test the modified Radiosurgery-based AVM score in a separate set of AVM patients managed with Radiosurgery. Methods and Materials The AVM score is calculated as follows: AVM score=(0.1)(volume, cc) + (0.02)(age, years) + (0.5)(location; frontal/temporal/parietal/occipital/intraventricular/corpus callosum/cerebellar = 0, basal ganglia/thalamus/brainstem = 1). Testing of the modified system was performed on 293 patients having AVM Radiosurgery from 1992 to 2004 at the University of Pittsburgh with dose planning based on a combination of stereotactic angiography and MRI. The median patient age was 38 years, the median AVM volume was 3.3 cc, and 57 patients (19%) had deep AVMs. The median modified AVM score was 1.25. The median patient follow-up was 39 months. Results The modified AVM scale correlated with the percentage of patients with AVM obliteration without new deficits (≤1.00, 62%; 1.01–1.50, 51%; 1.51–2.00, 53%; and >2.00, 32%; F = 11.002, R 2 = 0.8117, p = 0.001). Linear regression also showed a statistically significant correlation between outcome and dose prescribed to the margin ( F = 25.815, p Conclusions The modified Radiosurgery-based AVM grading scale using location as a two-tiered variable correlated with outcomes when tested on a cohort of patients who underwent both angiography and MRI for dose planning. This system can be used to guide choices among observation, endovascular, surgical, and radiosurgical management strategies for individual AVM patients.
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cranial nerve preservation and outcomes after stereotactic Radiosurgery for jugular foramen schwannomas
Neurosurgery, 2007Co-Authors: Juan J Martin, David Mathieu, Douglas Kondziolka, John C. Flickinger, Ajay Niranjan, Dade L LunsfordAbstract:OBJECTIVE: Jugular foramen region schwannomas are rare intracranial tumors that usually present with multiple lower cranial nerve deficits. For some patients, complete surgical resection is possible but may be associated with significant morbidity. Stereotactic Radiosurgery is a minimally invasive alternative or adjunct to microsurgery for such tumors. We reviewed our clinical and imaging outcomes after patients underwent gamma knife Radiosurgery for management of jugular foramen schwannomas. METHODS: Thirty-four patients with 35 tumors (one patient had bilateral tumors) underwent Radiosurgery between May 1990 and December 2005. Twenty-two patients had previous microsurgical resection and all patients experienced various cranial neuropathies. A median of six isocenters were used. Median marginal and maximum doses were 14 and 28 Gy, respectively. RESULTS: None of the patients were lost to evaluation and the mean duration of follow-up was 83 months. Tumors regressed in 17 patients, remained stable in 16, and progressed in two. Five- and 10-year actuarial control rates were 97 and 94%, respectively. Preexisting cranial neuropathies improved in 20% and remained stable in 77% after Radiosurgery. One patient worsened. The function of all previous intact nerves was preserved after Radiosurgery. CONCLUSION: Stereotactic Radiosurgery proved to be a safe and effective management for newly diagnosed or residual jugular foramen schwannomas. Long-term tumor control rates and stability or improvement in cranial nerve function was confirmed.
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recursive partitioning analysis of prognostic factors for patients with four or more intracranial metastases treated with Radiosurgery
Technology in Cancer Research & Treatment, 2007Co-Authors: Ajay Bhatnagar, Dade L Lunsford, Douglas Kondziolka, John C. FlickingerAbstract:The purpose of this study was to devise a new recursive partitioning analysis (RPA) of patients with four or more intracranial metastases treated with a single Radiosurgery procedure to identify a class of patients with extended survival. 205 patients underwent Gamma Knife Radiosurgery for four or more intracranial metastases (median = 5, range 4–18) during one session. The median total treatment volume was 6.8 cc (range 0.6–51.0 cc). Radiosurgery was used as sole management (17% of patients), or in combination with WB-RT (46%), or after failure of WB-RT (38%). The median marginal Radiosurgery dose was 16 Gy (range 12–20 Gy). RPA assessed the effects of age, Karnofsky >70, extracranial disease, visceral metastases, number of metastases, total treatment volume, history of breast and melanoma primaries on survival. The median overall survival after Radiosurgery for all patients was 8 months. RPA identified a favorable subgroup of 78 patients (43% of the series) with a total treatment volume <7 cc and < 7 br...
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stereotactic Radiosurgery for vestibular schwannomas in patients with neurofibromatosis type 2 an analysis of tumor control complications and hearing preservation rates
Neurosurgery, 2007Co-Authors: David Mathieu, Douglas Kondziolka, John C. Flickinger, Ajay Niranjan, Richard W Williamson, Juan J Martin, Dade L LunsfordAbstract:OBJECTIVE: Vestibular schwannomas present significant management challenges in patients with neurofibromatosis Type 2 (NF2). We evaluated the results of gamma knife Radiosurgery for the management of these tumors, focusing on tumor response, hearing preservation, and other factors affecting outcomes. METHODS: Stereotactic Radiosurgery was performed to manage 74 schwannomas in 62 patients. Ipsilateral serviceable hearing was present in 35% of tumors before the procedure. The mean tumor volume was 5.7 cm3. The mean margin and maximum dose used were 14 and 27.5 Gy, respectively. Cox regression analyses were performed to to identify factors affecting outcomes. RESULTS: The median follow-up period was 53 months, and two patients were lost to follow-up. Actuarial local control rates at were 85, 81, and 81 % at 5, 10, and 15 years, respectively. Tumor volume was significant as a predictor of local control. Since 1992, using current Radiosurgery techniques (magnetic resonance imaging scan targeting and reduced margin dose to 14 Gy or less), the actuarial serviceable hearing preservation rate is 73% at 1 year, 59% at 2 years, and 48% at 5 years after Radiosurgery. Facial neuropathy occurred in 8% of tumors, trigeminal neuropathy occurred in 4%, and vestibular dysfunction occurred in 4%. Radiation dose and tumor volume were predictive of development of new deficits. No Radiosurgery-associated secondary tumors or atypical or malignant changes were noted. CONCLUSION: Stereotactic Radiosurgery is a safe and effective management modality for neurofibromatosis Type 2 vestibular schwannomas. Although results do not seem to be as good as for patients with sporadic unilateral tumors, gamma knife Radiosurgery results seem favorable and indicate that Radiosurgery should be strongly considered for primary tumor management in selected patients.
Dade L Lunsford - One of the best experts on this subject based on the ideXlab platform.
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intracranial Radiosurgery an effective and disruptive innovation in neurosurgery
Stereotactic and Functional Neurosurgery, 2012Co-Authors: Ajay Niranjan, Ravindranath Madhavan, Peter C Gerszten, Dade L LunsfordAbstract:Physicians are guided by the teachings of their chosen field, standards of accepted practice, peer pressure, prior training, and other sources of bias. When potential bias begins to impact recommendations for care in the field of tumor management, physicians may fail to realize the importance of emerging medical innovations. Some of these ultimately turn out to be ‘disruptive innovations.’ These innovations are more often than not both low risk and cost effective. But the leaders in the field often initially ignore these newer technologies in favor of more mature existing technologies. However, over time these technologies gradually improve and become mainstream management practices. Intracranial Radiosurgery is one such innovation which was not embraced by the neurosurgical community in the beginning. Nowadays, a wide variety of brain and body disorders are treated with Radiosurgery. Acoustic neuromas and brain metastases are examples of rapidly growing indications of Radiosurgery. In this report, the authors describe the emergence of stereotactic Radiosurgery as a disruptive innovation in the field of medicine.
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a modified Radiosurgery based arteriovenous malformation grading scale and its correlation with outcomes
International Journal of Radiation Oncology Biology Physics, 2011Co-Authors: Rodney E Wegner, Bruce E. Pollock, Dade L Lunsford, Douglas Kondziolka, Ajay Niranjan, Kaan Oysul, Sait Sirin, John C. FlickingerAbstract:Purpose The Pittsburgh Radiosurgery-based arteriovenous malformation (AVM) grading scale was developed to predict patient outcomes after Radiosurgery and was later modified with location as a two-tiered variable (deep vs. other). The purpose of this study was to test the modified Radiosurgery-based AVM score in a separate set of AVM patients managed with Radiosurgery. Methods and Materials The AVM score is calculated as follows: AVM score=(0.1)(volume, cc) + (0.02)(age, years) + (0.5)(location; frontal/temporal/parietal/occipital/intraventricular/corpus callosum/cerebellar = 0, basal ganglia/thalamus/brainstem = 1). Testing of the modified system was performed on 293 patients having AVM Radiosurgery from 1992 to 2004 at the University of Pittsburgh with dose planning based on a combination of stereotactic angiography and MRI. The median patient age was 38 years, the median AVM volume was 3.3 cc, and 57 patients (19%) had deep AVMs. The median modified AVM score was 1.25. The median patient follow-up was 39 months. Results The modified AVM scale correlated with the percentage of patients with AVM obliteration without new deficits (≤1.00, 62%; 1.01–1.50, 51%; 1.51–2.00, 53%; and >2.00, 32%; F = 11.002, R 2 = 0.8117, p = 0.001). Linear regression also showed a statistically significant correlation between outcome and dose prescribed to the margin ( F = 25.815, p Conclusions The modified Radiosurgery-based AVM grading scale using location as a two-tiered variable correlated with outcomes when tested on a cohort of patients who underwent both angiography and MRI for dose planning. This system can be used to guide choices among observation, endovascular, surgical, and radiosurgical management strategies for individual AVM patients.
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cranial nerve preservation and outcomes after stereotactic Radiosurgery for jugular foramen schwannomas
Neurosurgery, 2007Co-Authors: Juan J Martin, David Mathieu, Douglas Kondziolka, John C. Flickinger, Ajay Niranjan, Dade L LunsfordAbstract:OBJECTIVE: Jugular foramen region schwannomas are rare intracranial tumors that usually present with multiple lower cranial nerve deficits. For some patients, complete surgical resection is possible but may be associated with significant morbidity. Stereotactic Radiosurgery is a minimally invasive alternative or adjunct to microsurgery for such tumors. We reviewed our clinical and imaging outcomes after patients underwent gamma knife Radiosurgery for management of jugular foramen schwannomas. METHODS: Thirty-four patients with 35 tumors (one patient had bilateral tumors) underwent Radiosurgery between May 1990 and December 2005. Twenty-two patients had previous microsurgical resection and all patients experienced various cranial neuropathies. A median of six isocenters were used. Median marginal and maximum doses were 14 and 28 Gy, respectively. RESULTS: None of the patients were lost to evaluation and the mean duration of follow-up was 83 months. Tumors regressed in 17 patients, remained stable in 16, and progressed in two. Five- and 10-year actuarial control rates were 97 and 94%, respectively. Preexisting cranial neuropathies improved in 20% and remained stable in 77% after Radiosurgery. One patient worsened. The function of all previous intact nerves was preserved after Radiosurgery. CONCLUSION: Stereotactic Radiosurgery proved to be a safe and effective management for newly diagnosed or residual jugular foramen schwannomas. Long-term tumor control rates and stability or improvement in cranial nerve function was confirmed.
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recursive partitioning analysis of prognostic factors for patients with four or more intracranial metastases treated with Radiosurgery
Technology in Cancer Research & Treatment, 2007Co-Authors: Ajay Bhatnagar, Dade L Lunsford, Douglas Kondziolka, John C. FlickingerAbstract:The purpose of this study was to devise a new recursive partitioning analysis (RPA) of patients with four or more intracranial metastases treated with a single Radiosurgery procedure to identify a class of patients with extended survival. 205 patients underwent Gamma Knife Radiosurgery for four or more intracranial metastases (median = 5, range 4–18) during one session. The median total treatment volume was 6.8 cc (range 0.6–51.0 cc). Radiosurgery was used as sole management (17% of patients), or in combination with WB-RT (46%), or after failure of WB-RT (38%). The median marginal Radiosurgery dose was 16 Gy (range 12–20 Gy). RPA assessed the effects of age, Karnofsky >70, extracranial disease, visceral metastases, number of metastases, total treatment volume, history of breast and melanoma primaries on survival. The median overall survival after Radiosurgery for all patients was 8 months. RPA identified a favorable subgroup of 78 patients (43% of the series) with a total treatment volume <7 cc and < 7 br...
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stereotactic Radiosurgery for vestibular schwannomas in patients with neurofibromatosis type 2 an analysis of tumor control complications and hearing preservation rates
Neurosurgery, 2007Co-Authors: David Mathieu, Douglas Kondziolka, John C. Flickinger, Ajay Niranjan, Richard W Williamson, Juan J Martin, Dade L LunsfordAbstract:OBJECTIVE: Vestibular schwannomas present significant management challenges in patients with neurofibromatosis Type 2 (NF2). We evaluated the results of gamma knife Radiosurgery for the management of these tumors, focusing on tumor response, hearing preservation, and other factors affecting outcomes. METHODS: Stereotactic Radiosurgery was performed to manage 74 schwannomas in 62 patients. Ipsilateral serviceable hearing was present in 35% of tumors before the procedure. The mean tumor volume was 5.7 cm3. The mean margin and maximum dose used were 14 and 27.5 Gy, respectively. Cox regression analyses were performed to to identify factors affecting outcomes. RESULTS: The median follow-up period was 53 months, and two patients were lost to follow-up. Actuarial local control rates at were 85, 81, and 81 % at 5, 10, and 15 years, respectively. Tumor volume was significant as a predictor of local control. Since 1992, using current Radiosurgery techniques (magnetic resonance imaging scan targeting and reduced margin dose to 14 Gy or less), the actuarial serviceable hearing preservation rate is 73% at 1 year, 59% at 2 years, and 48% at 5 years after Radiosurgery. Facial neuropathy occurred in 8% of tumors, trigeminal neuropathy occurred in 4%, and vestibular dysfunction occurred in 4%. Radiation dose and tumor volume were predictive of development of new deficits. No Radiosurgery-associated secondary tumors or atypical or malignant changes were noted. CONCLUSION: Stereotactic Radiosurgery is a safe and effective management modality for neurofibromatosis Type 2 vestibular schwannomas. Although results do not seem to be as good as for patients with sporadic unilateral tumors, gamma knife Radiosurgery results seem favorable and indicate that Radiosurgery should be strongly considered for primary tumor management in selected patients.
Bruce E. Pollock - One of the best experts on this subject based on the ideXlab platform.
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gamma knife surgery for the management of glomus tumors a multicenter study
Journal of Neurosurgery, 2012Co-Authors: Jason P Sheehan, David Mathieu, Bruce E. Pollock, Douglas Kondziolka, Michael J Link, Anthony M Kaufmann, Shota Tanaka, Christopher Duma, Byron A Young, Heyoung McbrideAbstract:Object Glomus tumors are rare skull base neoplasms that frequently involve critical cerebrovascular structures and lower cranial nerves. Complete resection is often difficult and may increase cranial nerve deficits. Stereotactic Radiosurgery has gained an increasing role in the management of glomus tumors. The authors of this study examine the outcomes after Radiosurgery in a large, multicenter patient population. Methods Under the auspices of the North American Gamma Knife Consortium, 8 Gamma Knife surgery centers that treat glomus tumors combined their outcome data retrospectively. One hundred thirty-four patient procedures were included in the study (134 procedures in 132 patients, with each procedure being analyzed separately). Prior resection was performed in 51 patients, and prior fractionated external beam radiotherapy was performed in 6 patients. The patients' median age at the time of Radiosurgery was 59 years. Forty percent had pulsatile tinnitus at the time of Radiosurgery. The median dose to t...
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a modified Radiosurgery based arteriovenous malformation grading scale and its correlation with outcomes
International Journal of Radiation Oncology Biology Physics, 2011Co-Authors: Rodney E Wegner, Bruce E. Pollock, Dade L Lunsford, Douglas Kondziolka, Ajay Niranjan, Kaan Oysul, Sait Sirin, John C. FlickingerAbstract:Purpose The Pittsburgh Radiosurgery-based arteriovenous malformation (AVM) grading scale was developed to predict patient outcomes after Radiosurgery and was later modified with location as a two-tiered variable (deep vs. other). The purpose of this study was to test the modified Radiosurgery-based AVM score in a separate set of AVM patients managed with Radiosurgery. Methods and Materials The AVM score is calculated as follows: AVM score=(0.1)(volume, cc) + (0.02)(age, years) + (0.5)(location; frontal/temporal/parietal/occipital/intraventricular/corpus callosum/cerebellar = 0, basal ganglia/thalamus/brainstem = 1). Testing of the modified system was performed on 293 patients having AVM Radiosurgery from 1992 to 2004 at the University of Pittsburgh with dose planning based on a combination of stereotactic angiography and MRI. The median patient age was 38 years, the median AVM volume was 3.3 cc, and 57 patients (19%) had deep AVMs. The median modified AVM score was 1.25. The median patient follow-up was 39 months. Results The modified AVM scale correlated with the percentage of patients with AVM obliteration without new deficits (≤1.00, 62%; 1.01–1.50, 51%; 1.51–2.00, 53%; and >2.00, 32%; F = 11.002, R 2 = 0.8117, p = 0.001). Linear regression also showed a statistically significant correlation between outcome and dose prescribed to the margin ( F = 25.815, p Conclusions The modified Radiosurgery-based AVM grading scale using location as a two-tiered variable correlated with outcomes when tested on a cohort of patients who underwent both angiography and MRI for dose planning. This system can be used to guide choices among observation, endovascular, surgical, and radiosurgical management strategies for individual AVM patients.
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modification of the Radiosurgery based arteriovenous malformation grading system
Neurosurgery, 2008Co-Authors: Bruce E. Pollock, John C. FlickingerAbstract:OBJECTIVE: The Radiosurgery-based arteriovenous malformation (AVM) grading scale was developed to predict patient outcomes after Radiosurgery. The purpose of this study was to determine whether simplifying this grading system using location as a two-tiered variable detracted from the accuracy of the scale. METHODS: Regression analysis modeling on 220 patients who underwentAVM Radiosurgery between 1987 and 1992 at the University of Pittsburgh Medical Center using location as a two-tiered variable resulted in the following equation: AVM score = (0.1) (volume, mL) + (0.02) (age, yr) + (0.3) (location, hemispheric/corpus callosum/cerebellar = 0; basal ganglia/thalamus/brainstem = 1). Testing of the modified grading system was performed on 247 patients who underwent AVM Radiosurgery between 1990 and 2001 at the Mayo Clinic. The mean modified AVM score was 1.62. The mean duration of patient follow-up was 70 months. RESULTS: There was no difference between the original and modified Radiosurgery-based AVM scale with regard to AVM obliteration without new neurological deficits (F = 0.92, P = 0.53) or decline in Modified Rankin Scale (F= 0.83, P = 0.56) after radio-surgery. The modified Radiosurgery-based AVM scale correlated with the percentage of patients with AVM obliteration without new deficits (= ≤ 1.00, 89%; 1.01-1.50, 70%; 1.51-2.00, 64%; ≥2.00, 46%) (r = -0.98, P 2.00, 36%) (r= 0.99, P < 0.01). CONCLUSION: Simplifying the Radiosurgery-based AVM grading system using location as a two-tiered variable did not detract from the accuracy of the scale. This system has been validated by numerous centers performing both gamma knife- and linear accelerator-based procedures and should be used in future studies on AVM Radiosurgery to stratify patients for more accurate comparative analyses.
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gamma knife Radiosurgery for patients with nonfunctioning pituitary adenomas results from a 15 year experience
International Journal of Radiation Oncology Biology Physics, 2008Co-Authors: Bruce E. Pollock, Scott L. Stafford, Robert L. Foote, Michael J Link, Paul D Brown, Joseph Cochran, Neena Natt, Dana Erickson, Yolanda I Garces, Paula J. SchombergAbstract:Purpose To evaluate the efficacy and complications of stereotactic Radiosurgery for patients with nonfunctioning pituitary adenomas (NFA). Methods and Materials This was a retrospective review of 62 patients with NFA undergoing Radiosurgery between 1992 and 2004, of whom 59 (95%) underwent prior tumor resection. The median treatment volume was 4.0 cm 3 (range, 0.8–12.9). The median treatment dose to the tumor margin was 16 Gy (range, 11–20). The median maximum point dose to the optic apparatus was 9.5 Gy (range, 5.0–12.6). The median follow-up period after Radiosurgery was 64 months (range, 23–161). Results Tumor size decreased for 37 patients (60%) and remained unchanged for 23 patients (37%). Two patients (3%) had tumor growth outside the prescribed treatment volume and required additional treatment (fractionated radiation therapy, n = 1; repeat Radiosurgery, n = 1). Tumor growth control was 95% at 3 and 7 years after Radiosurgery. Eleven (27%) of 41 patients with normal ( n = 30) or partial ( n = 11) anterior pituitary function before Radiosurgery developed new deficits at a median of 24 months after Radiosurgery. The risk of developing new anterior pituitary deficits at 5 years was 32%. The 5-year risk of developing new anterior pituitary deficits was 18% for patients with a tumor volume of ≤4.0 cm 3 compared with 58% for patients with a tumor volume >4.0 cm 3 (risk ratio=4.5; 95% confidence interval=1.3–14.9, p = 0.02). No patient had a decline in visual function. Conclusions Stereotactic Radiosurgery is effective in the management of patients with residual or recurrent NFA, although longer follow-up is needed to evaluate long-term outcomes. The primary complication is hypopituitarism, and the risk of developing new anterior pituitary deficits correlates with the size of the irradiated tumor.
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Radiosurgery of growth hormone producing pituitary adenomas factors associated with biochemical remission
Journal of Neurosurgery, 2007Co-Authors: Bruce E. Pollock, Paul D Brown, Jeffrey T Jacob, Todd B NippoldtAbstract:Object The authors reviewed outcomes after stereotactic Radiosurgery for patients with acromegaly and analyzed factors associated with biochemical remission. Methods Retrospective analysis was performed for 46 consecutive cases of growth hormone (GH)–producing pituitary adenomas treated by Radiosurgery between 1991 and 2004. Biochemical remission was defined as a fasting GH less than 2 ng/ml and a normal age- and sex-adjusted insulin-like growth factor–I (IGF-I) level while patients were not receiving any pituitary suppressive medications. The median follow up after Radiosurgery was 63 months (range 22–168 months). Twenty-three patients (50%) had biochemical remission documented at a median of 36 months (range 6–63 months) after one radiosurgical procedure. The actuarial rates of biochemical remission at 2 and 5 years after Radiosurgery were 11 and 60%, respectively. Multivariate analysis showed that IGF-I levels less than 2.25 times the upper limit of normal (hazard ratio [HR] 2.9, 95% confidence interva...
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gamma knife surgery for the management of glomus tumors a multicenter study
Journal of Neurosurgery, 2012Co-Authors: Jason P Sheehan, David Mathieu, Bruce E. Pollock, Douglas Kondziolka, Michael J Link, Anthony M Kaufmann, Shota Tanaka, Christopher Duma, Byron A Young, Heyoung McbrideAbstract:Object Glomus tumors are rare skull base neoplasms that frequently involve critical cerebrovascular structures and lower cranial nerves. Complete resection is often difficult and may increase cranial nerve deficits. Stereotactic Radiosurgery has gained an increasing role in the management of glomus tumors. The authors of this study examine the outcomes after Radiosurgery in a large, multicenter patient population. Methods Under the auspices of the North American Gamma Knife Consortium, 8 Gamma Knife surgery centers that treat glomus tumors combined their outcome data retrospectively. One hundred thirty-four patient procedures were included in the study (134 procedures in 132 patients, with each procedure being analyzed separately). Prior resection was performed in 51 patients, and prior fractionated external beam radiotherapy was performed in 6 patients. The patients' median age at the time of Radiosurgery was 59 years. Forty percent had pulsatile tinnitus at the time of Radiosurgery. The median dose to t...
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sunct syndrome successfully treated by gamma knife Radiosurgery case report
Cephalalgia, 2011Co-Authors: Khaled Effendi, Samir Jarjoura, David MathieuAbstract:Background: The SUNCT syndrome (short-unilateral neuralgiform headache with conjunctival injection and tearing) can be very disabling for affected patients and is often refractory to medical management. We report the first case of SUNCT with a successful response to stereotactic Radiosurgery without any adverse effect.Case: After failing optimal medical treatment, a 82-year old male patient suffering from SUNCT syndrome was treated with Gamma knife Radiosurgery. The trigeminal nerve and sphenopalatine ganglion were targeted with a maximum dose of 80 Gy each. The patient had complete pain cessation 2 weeks after the treatment, and remains pain-free with no medication at the latest follow-up 39 months after Radiosurgery. He did not have any side effect from the procedure.Conclusion: Gamma knife Radiosurgery is an option for medically refractory SUNCT patients.
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cranial nerve preservation and outcomes after stereotactic Radiosurgery for jugular foramen schwannomas
Neurosurgery, 2007Co-Authors: Juan J Martin, David Mathieu, Douglas Kondziolka, John C. Flickinger, Ajay Niranjan, Dade L LunsfordAbstract:OBJECTIVE: Jugular foramen region schwannomas are rare intracranial tumors that usually present with multiple lower cranial nerve deficits. For some patients, complete surgical resection is possible but may be associated with significant morbidity. Stereotactic Radiosurgery is a minimally invasive alternative or adjunct to microsurgery for such tumors. We reviewed our clinical and imaging outcomes after patients underwent gamma knife Radiosurgery for management of jugular foramen schwannomas. METHODS: Thirty-four patients with 35 tumors (one patient had bilateral tumors) underwent Radiosurgery between May 1990 and December 2005. Twenty-two patients had previous microsurgical resection and all patients experienced various cranial neuropathies. A median of six isocenters were used. Median marginal and maximum doses were 14 and 28 Gy, respectively. RESULTS: None of the patients were lost to evaluation and the mean duration of follow-up was 83 months. Tumors regressed in 17 patients, remained stable in 16, and progressed in two. Five- and 10-year actuarial control rates were 97 and 94%, respectively. Preexisting cranial neuropathies improved in 20% and remained stable in 77% after Radiosurgery. One patient worsened. The function of all previous intact nerves was preserved after Radiosurgery. CONCLUSION: Stereotactic Radiosurgery proved to be a safe and effective management for newly diagnosed or residual jugular foramen schwannomas. Long-term tumor control rates and stability or improvement in cranial nerve function was confirmed.
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stereotactic Radiosurgery for vestibular schwannomas in patients with neurofibromatosis type 2 an analysis of tumor control complications and hearing preservation rates
Neurosurgery, 2007Co-Authors: David Mathieu, Douglas Kondziolka, John C. Flickinger, Ajay Niranjan, Richard W Williamson, Juan J Martin, Dade L LunsfordAbstract:OBJECTIVE: Vestibular schwannomas present significant management challenges in patients with neurofibromatosis Type 2 (NF2). We evaluated the results of gamma knife Radiosurgery for the management of these tumors, focusing on tumor response, hearing preservation, and other factors affecting outcomes. METHODS: Stereotactic Radiosurgery was performed to manage 74 schwannomas in 62 patients. Ipsilateral serviceable hearing was present in 35% of tumors before the procedure. The mean tumor volume was 5.7 cm3. The mean margin and maximum dose used were 14 and 27.5 Gy, respectively. Cox regression analyses were performed to to identify factors affecting outcomes. RESULTS: The median follow-up period was 53 months, and two patients were lost to follow-up. Actuarial local control rates at were 85, 81, and 81 % at 5, 10, and 15 years, respectively. Tumor volume was significant as a predictor of local control. Since 1992, using current Radiosurgery techniques (magnetic resonance imaging scan targeting and reduced margin dose to 14 Gy or less), the actuarial serviceable hearing preservation rate is 73% at 1 year, 59% at 2 years, and 48% at 5 years after Radiosurgery. Facial neuropathy occurred in 8% of tumors, trigeminal neuropathy occurred in 4%, and vestibular dysfunction occurred in 4%. Radiation dose and tumor volume were predictive of development of new deficits. No Radiosurgery-associated secondary tumors or atypical or malignant changes were noted. CONCLUSION: Stereotactic Radiosurgery is a safe and effective management modality for neurofibromatosis Type 2 vestibular schwannomas. Although results do not seem to be as good as for patients with sporadic unilateral tumors, gamma knife Radiosurgery results seem favorable and indicate that Radiosurgery should be strongly considered for primary tumor management in selected patients.
