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ABSTRACT: We sought to define the long-term benefits and risks of stereotactic radiosurgery (SRS) for arteriovenous malformation (AVM) patients who underwent prior embolization. Between 1987 and 2006, we performed Gamma Knife® SRS on 120 patients with AVM who underwent embolization followed by SRS. Sixty-four patients (53%) had at least 1 prior hemorrhage. The median number of embolizations varied from 1 to 5. The median target volume was 6.6 cm(3) (range, 0.2-26.3 cm(3)). The median margin dose was 18 Gy (range, 13.5-25 Gy). After embolization, 25 patients (21%) developed symptomatic neurological deficits. The overall rates of total obliteration documented by either angiography or magnetic resonance imaging were 35, 53, 55 and 59% at 3, 4, 5 and 10 years, respectively. Nine patients (8%) had a hemorrhage during the latency interval and 7 patients died due to hemorrhage. The actuarial rates of AVM hemorrhage after SRS were 0.8, 3.5, 5.4, 7.7 and 7.7% at 1, 2, 3, 5 and 10 years, respectively. Permanent neurological deficits due to adverse radiation effects developed in 3 patients (2.5%) after SRS. Using a case-match control technique, we found that embolization prior to SRS was associated with a lower rate of total obliteration (p = 0.028) in comparison to radiosurgery alone. In this 20-year experience, we found that prior embolization reduced the rate of total obliteration after SRS and latency interval hemorrhage risks were not affected by prior embolization. In the future, the role of embolization after SRS should be explored.
Progress in neurological surgery 01/2013; 27:89-96.
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ABSTRACT: The purpose of this study was to define the risk of rebleeding after stereotactic radiosurgery (SRS) for hemorrhagic arteriovenous malformations with or without associated intracranial aneurysms.
Between 1987 and 2006, we performed Gamma Knife SRS on 996 patients with brain arteriovenous malformations; 407 patients had sustained an arteriovenous malformation hemorrhage. Sixty-four patients (16%) underwent prior embolization and 84 (21%) underwent prior surgical resection. The median target volume was 2.3 mL (range, 0.1-20.7 mL). The median margin dose was 20 Gy (range, 13.5-27 Gy).
The overall rate of total obliteration defined by angiography or MRI was 56%, 77%, 80%, and 82% at 3, 4, 5, and 10 years, respectively. Before obliteration, 33 patients (8%) sustained an additional hemorrhage after SRS. The overall annual hemorrhage rate until obliteration after SRS was 1.3%. The presence of a patent aneurysm was significantly associated with an increased rehemorrhage risk after SRS (annual hemorrhage rate, 6.4%) compared with patients with a clipped or embolized aneurysm (annual hemorrhage rate, 0.8%; P=0.033).
When an aneurysm is identified in patients with arteriovenous malformations selected for SRS, additional endovascular or surgical strategies should be considered to reduce the risk of bleeding during the latency interval.
Stroke 08/2012; 43(10):2586-91. · 5.73 Impact Factor
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ABSTRACT: In this paper the authors' goal was to define the long-term benefits and risks of stereotactic radiosurgery (SRS) for patients with arteriovenous malformations (AVMs) who underwent prior embolization.
Between 1987 and 2006, the authors performed Gamma Knife surgery in 996 patients with brain AVMs; 120 patients underwent embolization followed by SRS. In this series, 64 patients (53%) had at least one prior hemorrhage. The median number of embolizations varied from 1 to 5. The median target volume was 6.6 cm(3) (range 0.2-26.3 cm(3)). The median margin dose was 18 Gy (range 13.5-25 Gy).
After embolization, 25 patients (21%) developed symptomatic neurological deficits. The overall rates of total obliteration documented by either angiography or MRI were 35%, 53%, 55%, and 59% at 3, 4, 5, and 10 years, respectively. Factors associated with a higher rate of AVM obliteration were smaller target volume, smaller maximum diameter, higher margin dose, timing of embolization during the most recent 10-year period (1997-2006), and lower Pollock-Flickinger score. Nine patients (8%) had a hemorrhage during the latency period, and 7 patients died of hemorrhage. The actuarial rates of AVM hemorrhage after SRS were 0.8%, 3.5%, 5.4%, 7.7%, and 7.7% at 1, 2, 3, 5, and 10 years, respectively. The overall annual hemorrhage rate was 2.7%. Factors associated with a higher risk of hemorrhage after SRS were a larger target volume and a larger number of prior hemorrhages. Permanent neurological deficits due to adverse radiation effects (AREs) developed in 3 patients (2.5%) after SRS, and 1 patient had delayed cyst formation 210 months after SRS. No patient died of AREs. A larger 12-Gy volume was associated with higher risk of symptomatic AREs. Using a case-control matched approach, the authors found that patients who underwent embolization prior to SRS had a lower rate of total obliteration (p = 0.028) than patients who had not undergone embolization.
In this 20-year experience, the authors found that prior embolization reduced the rate of total obliteration after SRS, and that the risks of hemorrhage during the latency period were not affected by prior embolization. For patients who underwent embolization to volumes smaller than 8 cm(3), success was significantly improved. A margin dose of 18 Gy or more also improved success. In the future, the role of embolization after SRS should be explored.
Journal of Neurosurgery 05/2012; 117(2):265-75. · 2.96 Impact Factor
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ABSTRACT: Gamma knife radiosurgery (GKRS) is an important additional strategy for unresected clinically active pituitary adenomas. Radiosurgery for acromegaly aims to achieve tumor growth control and endocrine remission, potentially obviating the need for lifetime medication suppression therapy. Forty patients with clinically active acromegaly underwent GKRS between 1988 and 2009. Thirty-four patients had undergone prior surgical resection. The median follow-up interval was 72 months (range 24-145). Endocrine remission was defined as growth hormones (GH) level <2.5 ng/ml and a normal insulin-like growth factor 1 (IGF-1) level (age and sex adjusted) off growth hormone inhibiting drugs for at least 3 months. Endocrine control was defined as normal GH and IGF-1 levels on suppression medication. Endocrine remission was achieved in 19 (47.5 %) patients and endocrine control in four additional (10.0 %) patients. Patients with lower IGF-1 level and with tumors that were less invasive of the cavernous sinus before GKRS were associated with better GH remission rates. Imaging-defined local tumor control was achieved in 39 (97.5 %) patients (27 had tumor regression). One patient with delayed tumor progression underwent a second GKRS procedure. Three other patients had repeat GKRS because of persistently elevated and clinically symptomatic GH and IGF-1 levels. Sixteen (40.0 %) patients eventually developed a new pituitary axis deficiency at a median onset of 36 months after radiosurgery. No patient developed new visual dysfunction. Gamma knife radiosurgery, which is most often applied in clinically symptomatic acromegaly persistent after initial microsurgery, was most effective when the tumor was less invasive of the cavernous sinus and when patients had lower IGF-1 levels before GKRS. Almost one half of the patients no longer required long term medication suppression.
Journal of Neuro-Oncology 04/2012; 109(1):71-9. · 3.21 Impact Factor
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ABSTRACT: To assess outcomes after stereotactic radiosurgery (SRS) for chondrosarcomas of the skull base, we reviewed 22 patients with cranial base chondrosarcomas who underwent SRS between 1987 and 2009. The median patient age was 42 years (range, 15-75). The median SRS target volume was 8.0 cc (range, 0.9-28.2) and median margin dose was 15.0 Gy (range, 10.5-20). 15 patients (68 %) underwent one or more tumor resections and 3 of these patients also had fractionated radiation therapy. At a median follow-up of 75 months after SRS, seven patients died due to tumor progression. The actuarial overall survival after SRS for the entire group of chondrosarcoma patients was 95, 76, 70 and 56 % at 1, 3, 5 and 10 years, respectively. Factors associated with longer survival after SRS included patient age >40 years, a shorter interval (<6 months) between diagnosis and SRS, and either no or a single prior resection. Treated tumor control rates were 91, 72, 72 and 54 % at 1, 3, 5 and 10 years, respectively. Factors associated with longer progression-free survival after SRS included patient age >40 years and no prior RT. Symptomatic adverse radiation effects occurred in two patients (10 %). Stereotactic radiosurgery may provide a benefit to patients as either a primary or adjuvant therapy. The ability to achieve tumor control in patients with chondrosarcoma is likely to be enhanced by earlier timing of SRS after diagnosis and multimodal management, beginning with resection when feasible followed by early SRS for progressive residual tumor.
Journal of Neuro-Oncology 04/2012; 108(3):535-42. · 3.21 Impact Factor
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ABSTRACT: We evaluated the efficacy and safety of gamma knife stereotactic radiosurgery (GKSR) followed by bevacizumab combined with chemotherapy in 11 patients with recurrent glioblastoma multiforme who experienced tumor progression despite aggressive initial multi-modality treatment. Our experience included eight male and three female patients. The median patient age at GKSR was 62 years (range 46-72 years). At the time of GKSR, seven patients had a first recurrence and four had two or more recurrences. The median interval from the initial diagnosis until GKSR was 17 months (range 5-34.5 months). The median tumor volume was 13.6 cm(3) (range 1.2-45.1 cm(3)) and the median margin dose of GKSR was 16 Gy (range 13-18 Gy). Following GKSR, bevacizumab was administrated with irinotecan in nine patients and with temozolomide in one patient. One patient was treated with bevacizumab monotherapy. The treatment outcomes were compared to 44 case-matched controls who underwent GKSR without additional bevacizumab. At a median of 13.7 months (range 4.6-28.3 months) after radiosurgery, tumor progression was evident in seven patients. The median progression-free survival (PFS) was 15 months (95% confidential interval (CI), 6.5-23.3 months). Six-month and 1-year PFS rates were 73 and 55%, respectively. The median overall survival (OS) from GKSR was 18 months (95% CI, 10.1-25.7 months) and 1-year OS rate was 73%. One patient (9%) experienced grade III toxicity and one patient (9%) had major adverse radiation effects. Compared with patients who did not receive bevacizumab, the patients who received bevacizumab had significantly prolonged PFS (15 months vs. 7 months, P = 0.035) and OS (18 months vs. 12 months, P = 0.005), and were less likely to develop an adverse radiation effect (9 vs. 46%, P = 0.037). The combination of salvage GKSR followed by bevacizumab added potential benefit and little additional risk in a small group of patients with progressive glioblastoma. Further experience is needed to define the efficacy and long-term toxicity with this strategy.
Journal of Neuro-Oncology 11/2011; 107(2):323-33. · 3.21 Impact Factor
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ABSTRACT: Vertebrobasilar ectasia (VBE) is an unusual cause of trigeminal neuralgia (TN). The surgical options for patients with medically refractory pain include percutaneous or microsurgical rhizotomy and microvascular decompression (MVD). All such procedures can be technically challenging. This report evaluates the response to a minimally invasive procedure, Gamma Knife surgery (GKS), in patients with TN associated with severe vascular compression caused by VBE.
Twenty patients underwent GKS for medically refractory TN associated with VBE. The median patient age was 74 years (range 48-95 years). Prior surgical procedures had failed in 11 patients (55%). In 9 patients (45%), GKS was the first procedure they had undergone. The median target dose for GKS was 80 Gy (range 75-85 Gy). The median follow-up was 29 months (range 8-123 months) after GKS. The treatment outcomes were compared with 80 case-matched controls who underwent GKS for TN not associated with VBE.
Intraoperative MR imaging or CT scanning revealed VBE that deformed the brainstem in 50% of patients. The trigeminal nerve was displaced in cephalad or lateral planes in 60%. In 4 patients (20%), the authors could identify only the distal cisternal component of the trigeminal nerve as it entered into the Meckel cave. After GKS, 15 patients (75%) achieved initial pain relief that was adequate or better, with or without medication (Barrow Neurological Institute [BNI] pain scale, Grades I-IIIb). The median time until pain relief was 5 weeks (range 1 day-6 months). Twelve patients (60%) with initial pain relief reported recurrent pain between 3 and 43 months after GKS (median 12 months). Pain relief was maintained in 53% at 1 year, 38% at 2 years, and 10% at 5 years. Some degree of facial sensory dysfunction occurred in 10% of patients. Eventually, 14 (70%) of the 20 patients underwent an additional surgical procedure including repeat GKS, percutaneous procedure, or MVD at a median of 14 months (range 5-50 months) after the initial GKS. At the last follow-up, 15 patients (75%) had satisfactory pain control (BNI Grades I-IIIb), but 5 patients (25%) continued to have unsatisfactory pain control (BNI Grade IV or V). Compared with patients without VBE, patients with VBE were much less likely to have initial (p = 0.025) or lasting (p = 0.006) pain relief.
Pain control rates of GKS in patients with TN associated with VBE were inferior to those of patients without VBE. Multimodality surgical or medical management strategies were required in most patients with VBE.
Journal of Neurosurgery 09/2011; 116(1):73-81. · 2.96 Impact Factor
