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Object The surgical management of disabling tremor has gained renewed vigor with the availability of deep brain stimulation. However, in the face of an aging population of patients with increasing surgical comorbidities, noninvasive approaches for tremor management are needed. The authors' purpose was to study the technique and results of stereotactic radiosurgery performed in the era of MRI targeting. Methods The authors evaluated outcomes in 86 patients (mean age 71 years; number of procedures 88) who underwent a unilateral Gamma Knife thalamotomy (GKT) for tremor during a 15-year period that spanned the era of MRI-based target selection (1996–2011). Symptoms were related to essential tremor in 48 patients (19 age ≥ 80 years and 3 age ≥ 90 years), Parkinson disease in 27 patients (11 age ≥ 80 years [1 patient underwent bilateral procedures]), and multiple sclerosis in 11 patients (1 patient underwent bilateral procedures). A single 4-mm isocenter was used to deliver a maximum dose of 140 Gy to the posterior-inferior region of the nucleus ventralis intermedius. The Fahn-Tolosa-Marin clinical tremor rating scale was used to grade tremor, handwriting, and ability to drink. The median follow-up was 23 months. Results The mean tremor score was 3.28 ± 0.79 before and 1.81 ± 1.15 after (p < 0.0001) GKT; the mean handwriting score was 2.78 ± 0.82 and 1.62 ± 1.04, respectively (p < 0.0001); and the mean drinking score was 3.14 ± 0.78 and 1.80 ± 1.15, respectively (p < 0.0001). After GKT, 57 patients (66%) showed improvement in all 3 scores, 11 patients (13%) in 2 scores, and 2 patients (2%) in just 1 score. In 16 patients (19%) there was a failure to improve in any score. Two patients developed a temporary contralateral hemiparesis, 1 patient noted dysphagia, and 1 sustained facial sensory loss. Conclusions Gamma Knife thalamotomy in the MRI era was a safe and effective noninvasive surgical strategy for medically refractory tremor in the elderly or those with contraindications to deep brain stimulation or stereotactic radiofrequency (thermal) thalamotomy.

Background and Purpose— We evaluated risk factors associated with the development of adverse radiation effects (ARE) after stereotactic radiosurgery (SRS) for cerebral arteriovenous malformations (AVMs). Methods— We evaluated 755 patients with AVM who underwent a single Gamma Knife SRS procedure with at least a 2-year minimum follow-up. Eighty-seven patients (12%) underwent previous resection and 128 (17%) had previous embolization. The median target volume was 3.6 mL (range, 0.1–26.3 mL). The median margin dose was 20 Gy (range, 13–27 Gy). Results— Fifty-five patients (7%) developed symptomatic ARE at a median follow-up of 75 months. The cumulative rates of symptomatic ARE were 3.2%, 5.8%, 6.7%, and 7.5% at 1, 2, 3, and 5 years, respectively. Factors associated with a higher rate of developing symptomatic ARE included larger AVM volume, higher margin dose, larger 12-Gy volume, higher Spetzler–Martin grade, and higher radiosurgery-based score. The rates of developing symptomatic ARE were higher in the brain stem (22%) or thalamus (16%), compared with AVMs located in other brain locations (4%–8%). Nineteen patients (3%) sustained irreversible new neurological deficits related to ARE, and 1 patient died. The rates of irreversible symptomatic ARE were 0.8%, 1.9%, 2.1%, and 2.8% at 1, 2, 3, and 5 years, respectively. The 5-year cumulative rates of irreversible symptomatic ARE were 9.1% in thalamus, 12.1% in brain stem, and 1.4% in other locations. Conclusions— The knowledge of ARE risk rates after AVM radiosurgery can assist informed consent for patients with AVM, their families, and healthcare providers.

OBJECTIVE The authors of this study evaluate the long-term outcomes of stereotactic radiosurgery (SRS) for cavernous sinus meningioma (CSM). METHODS The authors retrospectively assessed treatment outcomes 5-18 years after SRS in 200 patients with CSM. The median patient age was 57 years (range 22-83 years). In total, 120 (60%) patients underwent Gamma Knife SRS as primary management, 46 (23%) for residual tumors, and 34 (17%) for recurrent tumors after one or more surgical procedures. The median tumor target volume was 7.5 cm (range 0.1-37.3 cm), and the median margin dose was 13.0 Gy (range 10-20 Gy). RESULTS Tumor volume regressed in 121 (61%) patients, was unchanged in 49 (25%), and increased over time in 30 (15%) during a median imaging follow-up of 101 months. Actuarial tumor control rates at the 5-, 10-, and 15-year follow-ups were 92%, 84%, and 75%, respectively. Of the 120 patients who had undergone SRS as a primary treatment (primary SRS), tumor progression was observed in 14 (11.7%) patients at a median of 48.9 months (range 4.8-120.0 months) after SRS, and actuarial tumor control rates were 98%, 93%, 85%, and 85% at the 1-, 5-, 10-, and 15-year follow-ups post-SRS. A history of tumor progression after microsurgery was an independent predictor of an unfavorable response to radiosurgery (p = 0.009, HR = 4.161, 95% CI 1.438-12.045). Forty-four (26%) of 170 patients who had presented with at least one cranial nerve (CN) deficit improved after SRS. Development of new CN deficits after initial microsurgical resection was an unfavorable factor for improvement after SRS (p = 0.014, HR = 0.169, 95% CI 0.041-0.702). Fifteen (7.5%) patients experienced permanent CN deficits without evidence of tumor progression at a median onset of 9 months (range 2.3-85 months) after SRS. Patients with larger tumor volumes (≥ 10 cm) were more likely to develop permanent CN complications (p = 0.046, HR = 3.629, 95% CI 1.026-12.838). Three patients (1.5%) developed delayed pituitary dysfunction after SRS. CONCLUSIONS This long-term study showed that Gamma Knife radiosurgery provided long-term tumor control for most patients with CSM. Patients who underwent SRS for progressive tumors after prior microsurgery had a greater chance of tumor growth than the patients without prior surgery or those with residual tumor treated after microsurgery.

SRS provided long-term effective tumor control and a low risk of new cranial nerve deficits. Improvement in preexisting cranial neuropathies was detected in significantly more patients who had not undergone prior microsurgical procedures.

BackgroundDespite growing interest in the transradial approach for neurovascular procedures, prospective data about the learning curve for neurointerventionalists adopting this approach are limited.MethodsA subsequent prospective series of 50 consecutive right transradial diagnostic cerebral arteriograms was compared with our initial institutional experience using a procedural staging system. The primary outcome was the ability to achieve the predefined procedural goals using the radial approach. Secondary outcomes included the technical ability to access and inject each supraaortic artery of interest and the incidence of complications.ResultsThe primary outcome was achieved in 49 patients (98%) compared with 88% in the initial series (p=0.05). One stage 2 failure (2%) occurred. Crossover to the transfemoral approach occurred in one patient (2%) compared with 8% in the initial series (p=0.16). All supraaortic arteries of interest were accessed and injected with success rates between 93% and 100%. There were no major complications and two minor complications.ConclusionNeurointerventionalists can overcome the right transradial learning curve and achieve high success rates and low crossover rates after performing 30–50 cases.

Object The purpose of this study was to define the outcomes and risks of stereotactic radiosurgery (SRS) for Spetzler-Martin (SM) Grade III arteriovenous malformations (AVMs). Methods Between 1987 and 2009, SRS was performed in 474 patients with SM Grade III AVMs. The AVMs were categorized by scoring the size (S), drainage (D), and location (L): IIIa was a small AVM (S1D1L1, N = 282); IIIb was a medium/deep AVM (S2D1L0, N = 44); and IIIc was a medium/eloquent AVM (S2D0L1, N = 148). The median target volume was 3.8 ml (range 0.1–26.3 ml) and the margin dose was 20 Gy (range 13–25 Gy). Eighty-one patients (17%) underwent prior embolization, and 58 (12%) underwent prior resection. Results At a mean follow-up of 89 months, the total obliteration rates documented by angiography or MRI for all SM Grade III AVMs increased from 48% at 3 years to 69% at 4 years, 72% at 5 years, and 77% at 10 years. The SM Grade IIIa AVMs were more likely to obliterate than other subgroups. The cumulative rate of hemorrhage was 2.3% at 1 year, 4.4% at 2 years, 5.5% at 3 years, 6.4% at 5 years, and 9% at 10 years. The SM Grade IIIb AVMs had a significantly higher cumulative rate of hemorrhage. Symptomatic adverse radiation effects were detected in 6%. Conclusions Treatment with SRS was an effective and relatively safe management option for SM Grade III AVMs. Although patients with residual AVMs remained at risk for hemorrhage during the latency interval, the cumulative 10-year 9% hemorrhage risk in this series may represent a significant reduction compared with the expected natural history.

IntroductionFor patients undergoing mechanical thrombectomy, numerous (>3) thrombectomy passes may be harmful. However, non-recanalization leads to poor outcomes. For patients requiring multiple thrombectomy passes to achieve reperfusion, it remains unclear if the risk/benefit ratio favors recanalization.ObjectiveTo test the hypothesis that the benefits afforded by successful reperfusion outweigh the risk conveyed by the numerous passes required.MethodsWe retrospectively reviewed prospectively collected data for patients presenting to a comprehensive stroke center with anterior circulation large vessel occlusion (ACLVO) and undergoing thrombectomy requiring more than one pass over 24 months. We stratified patients into three groups: group 1 (successful reperfusion in 2–3 passes), group 2 (successful reperfusion in ≥4 passes), and group 3 (unsuccessful reperfusion).Results250 patients with ACLVO constituted the study cohort. Despite similar demographics, group 2 patients had better clinical outcomes than those in group 3 at 24 hours (National Institutes of Health Stroke Scale (NIHSS) score 13.5 vs 19.1, p<0.001) and at 90 days (modified Rankin Scale score 0–2 rates of 31.1% vs 0.0%, p=0.006) On multivariate logistic regression analysis, age (p=0.034), Alberta Stroke Program Early CT Score (p<0.01), NIHSS score (p=0.02), and parenchymal hematoma type 2 (p=0.015) were significant predictors of functional independence among those who achieved successful reperfusion, but the number of passes required did not predict outcome for these patients (p=0.74).ConclusionPatients who achieve successful reperfusion after many passes have better clinical outcomes than those who do not, despite the number of passes and procedural time required. The number of passes required to achieve successful reperfusion beyond the first pass is not a predictor of functional independence.