Search

An arachnoid web is a pathological formation of the arachnoid membrane. It is a rare phenomenon but is known to lead to syrinx formation in the spinal cord along with pain and neurological deficits. On imaging, the 'scalpel sign' is pathognomonic for an arachnoid web. The etiology of syrinx formation from an arachnoid web is currently unknown. This report documents the only two cases of arachnoid webs with an extensive syrinx in which a likely pathophysiologic mechanism is identified. Both cases presented with motor deficits. The patients had no history of trauma or infection. After extensive workup in both patients and observation of the scalpel sign an arachnoid web was suspected. In both cases, the patients were treated surgically after an arachnoid web was suspected. Intra-operative ultrasound visualized in both cases demonstrates a fenestration in the web that allowed passage of cerebrospinal fluid in a rostral-caudal direction due to a ball-valve effect.

Background and Purpose: Stereotactic radiosurgery (SRS) after maximal safe resection is an accepted treatment strategy for patients with cerebral metastatic disease. Despite its high conformality profile, the incidence of radionecrosis (RN) remains high. SRS delivered pre-operatively could be associated with a reduced incidence of RN. We sought to evaluate whether neoadjuvant SRS could reduce radiotherapy doses in a cohort of patients treated with post-operative SRS., Methods: A cohort of 47 brain metastases (BM) treated at 2 academic institutions was retrospectively analyzed. Subjects underwent surgical extirpation of BMs and subsequent SRS to surgical bed. Post-operative volumetric and dosimetric data was collected from records or recreations of delivered plans; pre-operative data were derived from hypothetical radiotherapy courses and compared using Wilcoxon signed-rank tests., Results: Higher planned tumor volume post-operatively (median[IQR] 12.28 [6.54, 18.69]cc vs 10.20 [4.53, 21.70]cc respectively, p = 0.4150) was observed. The median prescribed radiotherapy dose (DRx) was 16 Gy pre-operatively and 24 Gy post-operatively (p < 0.0001). Further investigations revealed improved pre-operative conformity index (1.23[1.20, 1.29] vs 1.29[1.23, 1.39], p = 0.0098) and gradient index (2.72[2.59, 2.98] vs 2.94[2.69, 3.47], p = 0.0004). A significant difference was found in normal brain tissue exposed to 10 Gy (12.97[6.78, 25.54]cc vs 32.13[19.42, 48.40]cc, p < 0.0001), 12 Gy (9.31[4.56, 17.43]cc vs 23.80[14.74, 36.56]cc, p < 0.0001), and 14 Gy (5.62[3.23, 11.61]cc vs 17.47[9.00, 28.31]cc, p < 0.0001), favoring pre-operative SRS., Conclusions: Neoadjuvant SRS is associated reduced DRx, better conformality profile and decreased radiation to normal tissue. These findings could support the use of neoadjuvant SRS for the treatment of BMs., (Copyright © 2022. Published by Elsevier B.V.)

Background: The current pandemic crisis, caused by a novel human coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV2), has forced a dramatic change in our society. A key portion of the medical work force on the frontline is composed of resident physicians. Thus, it becomes imperative to create an adequate and effective action plan to restructure this valuable human resource amid the SARS-CoV2 pandemic. We sought to describe a comprehensive approach taken by a Neurosurgery Department in quaternary care academic institution in the United States of America amid the SARS-CoV2 pandemic focused in resident training and support., Objective: To describe a comprehensive approach taken by a Neurosurgery Department in quaternary care academic institution in the United States of America amid the SARS-CoV2 pandemic focused on resident training and support., Results: A restructuring of the Neurosurgery Department at our academic institution was performed focused on decreasing their risk of infection/exposure and transmission to others, while minimizing negative consequences in the training experience. An online academic platform was built for resident education, guidance, and support, as well as continue channel for pandemic update by the department leadership., Conclusions: The SARS-CoV2 pandemic constitutes a global health emergency full of uncertainty. Treatment, scope, duration, and economic burden forced a major restructuring of our medical practice. In this regard, academic institutions must direct efforts to diminish further negative impact in the training and education of the upcoming generation of physicians, including those currently in medical school. Perhaps the only silver lining in this terrible disruption will be greater appreciation of the role of current health care providers and educators, whose contributions to our society are often neglected or unrecognized., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: We evaluated clinical outcomes in patients with symptomatic brainstem cavernous malformations (CMs) treated by stereotactic radiosurgery (SRS)., Methods: Between 1988 and 2016, Gamma Knife SRS was performed in 76 evaluable patients with solitary symptomatic brainstem CMs. Forty-nine (66%) were intrinsic (not reaching a pial or ependymal surface). Most patients (91%) had experienced 2 or more hemorrhages associated with new neurologic deficits. Fourteen patients (18%) underwent resection before radiosurgery. The median CM volume was 0.66 cm 3 (range, 0.05-6.8), and the median margin dose was 15.0 Gy., Results: After SRS, 15 patients (20%) had an imaging confirmed new hemorrhage at a median follow-up of 48 months. The hemorrhage-free survival after SRS for brainstem CMs was 92% at 1 year, 87% at 3 years, and 85% at 5 years. The annual hemorrhage rate was 31% before and 4% after SRS. In univariate analysis, CM volume, previous surgical resection, and increased number of hemorrhages before SRS were significantly associated with a higher rate of hemorrhage after SRS. In multivariate analysis, only number of previous hemorrhages was significant (P < 0.0005; hazard ratio, 1.51, 95% confidence interval, 1.23-1.85). Symptomatic adverse radiation effects developed in 7 patients (9%). The rate of symptom deterioration related to hemorrhage or symptomatic adverse radiation effects was 10% at 1 year, 18% at 3 years, and 20% at 5 years., Conclusions: Patients with an increased rate of hemorrhage before SRS had an increased risk of repeat hemorrhage and symptom deterioration rate after SRS. Intrinsic CM location did not significantly affect rates of symptom deterioration or rebleeding., (Copyright © 2018 Elsevier Inc. All rights reserved.)

OBJECTIVE The goal of this retrospective cohort study was to assess long-term outcomes in patients with vestibular schwannoma (VS) who underwent stereotactic radiosurgery (SRS) after initial microsurgical resection. METHODS From the authors' database of 1770 patients with VS, the authors retrospectively analyzed data from 173 Gamma Knife SRS procedures for VS after 1 (128 procedures) or multiple (45 procedures) microsurgical resections. The median length of the interval between the last resection and SRS was 42 months (range 2-329 months). The median length of clinical follow-up was 74 months (range 6-285 months). Progression-free survival after SRS was determined with Kaplan-Meier analysis. RESULTS At the time of SRS, the hearing of 161 patients (93%) was Gardner-Robertson Class V, and 81 patients (47%) had facial neuropathy (i.e., facial function with House-Brackmann [HB] grades of III-VI), 87 (50%) had trigeminal neuropathy, and 71 (41%) reported imbalance or disequilibrium disorders. The median tumor volume was 2.7 cm 3 (range 0.2-21.6 cm 3 ), and the median dose to the tumor margin was 13 Gy (range 11-20 Gy). Radiosurgery controlled growth of 163 (94%) tumors. Progression-free survival after SRS was 97% at 3 years, 95% at 5 years, and 90% at 10 years. Four patients with delayed tumor progression underwent repeat SRS at a median of 35 months (range 23-64 months) after the first SRS. Four patients (2.3%) with tumor progression underwent repeat resection at a median of 25 months (range 19-33 months). Among the patients with any facial dysfunction (indicated by HB grades of II-VI), 19% had improvement in this condition after SRS, and 5.5% with some facial function (indicated by HB grades of I-V) developed more facial weakness. Among patients with trigeminal neuropathy, 20% had improvement in this condition, and 5.8% developed or had worsened trigeminal neuropathy after SRS. CONCLUSIONS Stereotactic radiosurgery offered a safe and effective long-term management strategy for VS patients whose tumors remained or recurred after initial microsurgery.

OBJECTIVE Increased survival time after diagnosis of neoplastic disease has resulted in a gradual increase in spine tumor incidence. Radiosurgery is frequently a viable alternative to operative management in a population with severe medical comorbidities. The authors sought to assess the histopathological consequences of radiosurgery in the subset of patients progressing to operative intervention. METHODS Eighteen patients who underwent radiosurgery for spine tumors between 2008 and 2014 subsequently progressed to surgical treatment. A histopathological examination of these cases was performed. Indications for surgery included symptomatic compression fractures, radiographic instability, and symptoms of cord or cauda equina compression. Biopsy samples were obtained from the tumor within the radiosurgical zone in all cases and were permanently fixated. Viable tumor samples were stained for Ki 67. RESULTS Fifteen patients had metastatic lesions and 3 patients had neurofibromas. The mean patient age was 57 years. The operative indication was symptomatic compression in 10 cases (67%). The most frequent metastatic lesions were breast cancer (4 cases), renal cell carcinoma (3), prostate cancer (2), and endometrial cancer (2). In 9 (60%) of the 15 metastatic cases, histological examination of the lesions showed minimal evidence of inflammation. Viable tumor at the margins of the radiosurgery was seen in 9 (60%) of the metastatic cases. Necrosis in the tumor bed was frequent, as was fibrotic bone marrow. Vascular ectasia was seen in 2 of 15 metastatic cases, but sclerosis with ectasia was frequent. No evidence of malignant conversion was seen in the periphery of the lesions in the 3 neurofibroma cases. In 1 case of neurofibroma, the lesion demonstrated some small areas of remnant tumor in the radiosurgical target zone. CONCLUSIONS This case series demonstrates important histopathological characteristics of spinal lesions treated by SRS. Regions with the highest exposure to radiation appear to be densely necrotic and show little evidence of tumor growth, whereas peripheral regions distant from the radiation dosage are more likely to demonstrate viable tumor in malignant and benign neoplasms. Physiological tissue appears to be similarly affected. With additional investigation, a more homogenized field of hypofractionated radiation exposure may allow for tumor obliteration with relative preservation of critical anatomical structures.

Background: Intrathecal disc herniation is a rare but serious condition that has the potential to generate devastating neurologic deficits. We present a case of a 56-year-old man who developed cauda equina syndrome after several episodes of severe Valsalva maneuver., Case Description: The patient was found to have developed subacute urinary retention and leg weakness. Magnetic resonance imaging findings were concerning for an unusual-appearing lesion extending cranially at L2-3. Urgent decompression via an L2 laminectomy, exploration, and subsequent discectomy was performed. The patient recovered exceptionally well, regaining bladder function and ultimately being able to ambulate without assistance., Conclusions: Cranially extending intrathecal disc herniations are a rare phenomenon and exceptionally uncommon above L3. The clinician should have a high level of suspicion for herniation when looking at the clinical and historical information consistent with such a diagnosis even in the presence of ambiguous imaging findings., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Introduction: Traumatic bilateral locked facet joints occur with extreme rarity in the lumbar spine. A careful review of the literature revealed only three case reports., Clinical Presentation: We present the case of a 36 year-old male who suffered bilateral L4-5 facet fracture dislocations following a motor vehicle collision. The dislocation was associated with disruption of the posterior elements and a Grade II anterolisthesis of L4 on L5 as well as an epidural hematoma resulting in severe canal narrowing, with the patient remaining neurologically intact on presentation. The patient underwent open reduction with L3 to S1 pedicle screw fixation and arthrodesis to treat this highly unstable injury., Conclusion: The existing literature and a biomechanics review of the lumbar spine are described in the context of the presented case in addition to a proposed mechanism for such dislocations.

Parkinson disease (PD) is a common neurodegenerative disorder characterized by the presence of Lewy bodies and a reduction in the number of dopaminergic neurons in the substantia nigra of the basal ganglia. Common symptoms of PD include a reduction in control of voluntary movements, rigidity, and tremors. Such symptoms are marked by a severe deterioration in motor function. The causes of PD in many cases are unknown. PD has been found to be prominent in several notable people, including Adolf Hitler, the Chancellor of Germany and Führer of Nazi Germany during World War II. It is believed that Adolf Hitler suffered from idiopathic PD throughout his life. However, the effect of PD on Adolf Hitler's decision making during World War II is largely unknown. Here we examine the potential role of PD in shaping Hitler's personality and influencing his decision-making. We purport that Germany's defeat in World War II was influenced by Hitler's questionable and risky decision-making and his inhumane and callous personality, both of which were likely affected by his condition. Likewise his paranoid disorder marked by intense anti-Semitic beliefs influenced his treatment of Jews and other non-Germanic peoples. We also suggest that the condition played an important role in his eventual political decline., (Copyright © 2015 Elsevier Inc. All rights reserved.)

A simple method to co-culture granule neurons and glia from a single brain region is described, and microglia activation profiles are assessed in response to naturally occurring neuronal apoptosis, excitotoxin-induced neuronal death, and lipopolysaccharide (LPS) addition. Using neonatal rat cerebellar cortex as a tissue source, glial proliferation is regulated by omission or addition of the mitotic inhibitor cytosine arabinoside (AraC). After 7-8 days in vitro, microglia in AraC(-) cultures are abundant and activated based on their amoeboid morphology, expressions of ED1 and Iba1, and ability to phagocytose polystyrene beads and the majority of neurons undergoing spontaneous apoptosis. Microglia and phagocytic activities are sparse in AraC(+) cultures. Following exposure to excitotoxic kainate concentrations, microglia in AraC(-) cultures phagocytose most dead neurons within 24 h without exacerbating neuronal loss or mounting a strong or sustained inflammatory response. LPS addition induces a robust inflammatory response, based on microglial expressions of TNF-α, COX-2 and iNOS proteins, and mRNAs, whereas these markers are essentially undetectable in control cultures. Thus, the functional effector state of microglia is primed for phagocytosis but not inflammation or cytotoxicity even after kainate exposure that triggers death in the majority of neurons. This model should prove useful in studying the progressive activation states of microglia and factors that promote their conversion to inflammatory and cytotoxic phenotypes.

Object: A visual field deficit resulting from the management of an arteriovenous malformation (AVM) significantly impacts a patient's quality of life. The present study was designed to investigate the clinical and radiological outcomes of stereotactic radiosurgery (SRS) performed for AVMs involving the postgeniculate visual pathway., Methods: In this retrospective single-institution analysis, the authors reviewed their experience with Gamma Knife surgery for postgeniculate visual pathway AVMs performed during the period between 1987 and 2009., Results: During the study interval, 171 patients underwent SRS for AVMs in this region. Forty-one patients (24%) had a visual deficit prior to SRS. The median target volume was 6.0 cm3 (range 0.4-22 cm3), and 19 Gy (range 14-25 Gy) was the median margin dose. Obliteration of the AVM was confirmed in 80 patients after a single SRS procedure at a median follow-up of 74 months (range 5-297 months). The actuarial rate of total obliteration was 67% at 4 years. Arteriovenous malformations with a volume<5 cm3 had obliteration rates of 60% at 3 years and 79% at 4 years. The delivered margin dose proved significant given that 82% of patients receiving ≥22 Gy had complete obliteration. The AVM was completely obliterated in an additional 18 patients after they underwent repeat SRS. At a median of 25 months (range 11-107 months) after SRS, 9 patients developed new or worsened visual field deficits. One patient developed a complete homonymous hemianopia, and 8 patients developed quadrantanopias. The actuarial risk of sustaining a new visual deficit was 3% at 3 years, 5% at 5 years, and 8% at 10 years. Fifteen patients had hemorrhage during the latency period, resulting in death in 9 of the patients. The annual hemorrhage rate during the latency interval was 2%, and no hemorrhages occurred after confirmed obliteration., Conclusions: Despite an overall treatment mortality of 5%, related to latency interval hemorrhage, SRS was associated with only a 5.6% risk of new visual deficit and a final obliteration rate close to 80% in patients with AVMs of the postgeniculate visual pathway.

Delayed toxicity after whole brain radiation therapy (WBRT) is of increasing concern in patients who survive more than one year with brain metastases from breast cancer. Radiation-related white matter toxicity is detected by magnetic resonance imaging (MRI) and has been correlated with neurocognitive dysfunction. This study assessed the risk of developing white matter changes (WMC) in breast cancer patients who underwent either WBRT plus stereotactic radiosurgery (SRS) or SRS alone. We retrospectively compared 35 patients with breast cancer brain metastases who received WBRT and SRS to 30 patients who only received SRS. All patients had evaluable imaging at a median of one year after their initial management. The development of white matter T2 prolongation as detected by T2 or FLAIR imaging was graded: grade 1 = little or no white matter T2 hyperintensity; grade 2 = limited periventricular hyperintensity; and grade 3 = diffuse white matter hyperintensity. After WBRT plus SRS, patients demonstrated a significantly higher incidence of WMC (p < 0.0001). After one year, 71.5 % of patients whose treatment included WBRT demonstrated WMC (42.9 % grade 2; 28.6 % grade 3). Only one patient receiving only SRS developed WMC. In long-term survivors of breast cancer, the risk of WMC was significantly reduced when SRS alone was used for management. Further prospective studies are necessary to determine how these findings correlate with neurocognitive toxicity. WBRT usage as initial management of limited brain disease should be replaced by SRS alone to reduce the risk of delayed white matter toxicity.

Object: Gamma Knife radiosurgery (GKRS) is the least invasive treatment option for medically refractory, intractable trigeminal neuralgia (TN) and is especially valuable for treating elderly, infirm patients or those on anticoagulation therapy. The authors reviewed pain outcomes and complications in TN patients who required 3 radiosurgical procedures for recurrent or persistent pain., Methods: A retrospective review of all patients who underwent 3 GKRS procedures for TN at 4 participating centers of the North American Gamma Knife Consortium from 1995 to 2012 was performed. The Barrow Neurological Institute (BNI) pain score was used to evaluate pain outcomes., Results: Seventeen patients were identified; 7 were male and 10 were female. The mean age at the time of last GKRS was 79.6 years (range 51.2-95.6 years). The TN was Type I in 16 patients and Type II in 1 patient. No patient suffered from multiple sclerosis. Eight patients (47.1%) reported initial complete pain relief (BNI Score I) following their third GKRS and 8 others (47.1%) experienced at least partial relief (BNI Scores II-IIIb). The average time to initial response was 2.9 months following the third GKRS. Although 3 patients (17.6%) developed new facial sensory dysfunction following primary GKRS and 2 patients (11.8%) experienced new or worsening sensory disturbance following the second GKRS, no patient sustained additional sensory disturbances after the third procedure. At a mean follow-up of 22.9 months following the third GKRS, 6 patients (35.3%) reported continued Score I complete pain relief, while 7 others (41.2%) reported pain improvement (BNI Scores II-IIIb). Four patients (23.5%) suffered recurrent TN following the third procedure at a mean interval of 19.1 months., Conclusions: A third GKRS resulted in pain reduction with a low risk of additional complications in most patients with medically refractory and recurrent, intractable TN. In patients unsuitable for other microsurgical or percutaneous strategies, especially those receiving long-term oral anticoagulation or antiplatelet agents, GKRS repeated for a third time was a satisfactory, low risk option.

Stereotactic radiosurgery (SRS) has evolved into a mainstay in the primary and adjuvant management of most intracranial tumors. Central neurocytomas are rare, usually benign, intraventricular tumors that can be challenging to completely resect and often recur. Adjuvant therapy has been suggested for residual or recurrent tumors, especially in the setting of atypical neurocytomas. The limited data available suggest that SRS is a highly effective treatment approach for primary and adjuvant therapy, with tumor control rates of 80% to 90%. Due to its highly conformal and selective nature, SRS avoids the inconvenience and delayed toxicity of conventional radiation therapy., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Objective: Stereotactic radiosurgery (SRS) has evolved to become an established, well-studied treatment modality for intracranial pathologies traditionally treated with more invasive neurosurgical management. As the field expands, among neurosurgeons and across multiple disciplines, resident training will become increasingly crucial., Methods: In this review, we reflect on 25 years of SRS at the University of Pittsburgh Medical Center and the development of formal training in this area at our institution. We describe the formal resident rotation, fellowship opportunities, and training courses for multidisciplinary physician teams and allied health professionals., Results: The number of SRS cases performed annually has significantly increased in recent years and indeed surpassed caseloads for certain more traditional surgeries. Residents report high rates of expectation for including SRS in future practice, yet participate in only a small fraction of annual cases. The formal postgraduate year 3 rotation established at the University of Pittsburgh Medical Center provides a way to expose and educate residents in this growing subspecialty within the confines of duty hour regulations. In combination with extended clinical elective opportunities and postresidency fellowships, this rotation prepares residents at our institution for the use of SRS in future clinical practice., Conclusions: SRS is a rapidly expanding field that requires a unique skill set and current neurosurgical resident training often does not fully prepare trainees for its use in clinical practice. Focused resident training is necessary to ensure trainees are proficient in this specialty and well equipped to become leaders in the field., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: Infectious intracranial aneurysms (IIAs) are rare and potentially devastating. First-line management involves intravenous antibiotics, with surgical or endovascular management reserved for cases of failed medical treatment or aneurysmal rupture. Endovascular therapy has become the primary approach for treating these small, distally located aneurysms. Liquid embolic agents are well suited for use because of their ability to fill the aneurysm and parent vessel. We present our experience in treating these aneurysms via Onyx embolization and review the literature., Methods: We retrospectively reviewed the endovascular treatment of IIAs at our institution from 2010 to 2012. Eight patients with 16 IIAs ranging in size from 1 to 16 mm underwent treatment. Seven of the patients initially presented after aneurysmal rupture. Onyx was pushed until the aneurysm and parent artery were filled. Confirmation of aneurysmal occlusion was made by repeat cerebral angiography., Results: One symptomatic stroke occurred after embolization. Fourteen of the 16 aneurysms have been evaluated with follow-up angiography and remain occluded., Conclusions: Treatment of IIAs using an endovascular approach with Onyx is safe and effective.

Background: Repeat Gamma Knife stereotactic radiosurgery (GKSR) procedures are becoming common, especially for brain metastases. It is important to identify tumors requiring treatment at repeat GKSR and it can be challenging to distinguish treated tumors, tumor progression and new tumors. Using the image co-registration tool within the Leksell Gamma Plan software, we developed a technique to aid in the identification of tumors needing treatment., Objectives: The objective was to explore a new co-registration technique to identify tumors requiring treatment at repeat GKSR procedures., Methods: Ten patients who underwent repeat GKSR for brain metastases were identified. Contrast-enhanced volumetric T1 magnetic resonance images (MRI) from the previous GKSR were co-registered with the new images and the resulting two-color format image was used to evaluate tumor status., Results: Using the co-registered images, tumors were characterized as: resolved, regressed, stable, larger or new. Overall, 13.6% of tumors completely resolved, 26.2% regressed, 13.1% remained stable, while 7.9% progressed. Thirty-nine percent of tumors were new., Conclusions: The co-registration technique makes clinically relevant changes conspicuous on MRI. It distinguishes between tumors potentially requiring treatment and those that have been treated successfully. It can be used with tumors other than metastases and for evaluating tumor response at follow-up., (© 2014 S. Karger AG, Basel.)

Widespread availability of magnetic resonance imaging has helped our understanding of the natural history of cavernous malformations (CMs) of the brain. CMs present with diverse clinical manifestations. Supratentorial CMs are often identified incidentally. The clinical presentation corresponds with lesion location. Symptomatic, hemorrhagic CMs of the brainstem pose a challenging clinical problem as they are often associated with high surgical morbidity. In order to study the natural history of CM, we performed a prospective analysis on a series of patients who were sent to us for management. During the mean prospective follow-up interval of 34 months, 9 hemorrhages occurred. History of prior hemorrhage was the most important risk factor for subsequent hemorrhage. The annual hemorrhage was 0.6% in patients who never had a symptomatic hemorrhage. Patients who had prior hemorrhage have a higher (4.5%) annual hemorrhage rate., (Copyright © 2013 S. Karger AG, Basel.)

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 cm3 (range, 0.2-26.3 cm3). 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., (Copyright © 2013 S. Karger AG, Basel.)

Background: As systemic therapies improve and patients live longer, concerns mount about the toxicity of whole-brain radiation therapy (WBRT) for treatment of brain metastases. Development of delayed white matter abnormalities indicative of leukoencephalopathy have been correlated with cognitive dysfunction. This study assesses the risk of imaging-defined leukoencephalopathy in patients whose management included WBRT in addition to stereotactic radiosurgery (SRS). This risk is compared to patients who only underwent SRS., Methods: We retrospectively compared 37 patients with non-small cell lung cancer who underwent WBRT plus SRS to 31 patients who underwent only SRS. All patients survived at least 1 year after treatment. We graded the development of delayed white matter changes on magnetic resonance imaging using a scale to evaluate T(2) /FLAIR (fluid attenuated image recovery) images: grade 1 = little or no white matter hyperintensity; grade 2 = limited periventricular hyperintensity; and grade 3 = diffuse white matter hyperintensity., Results: Patients treated with WBRT and SRS had a significantly greater incidence of delayed white matter leukoencephalopathy compared to patients who underwent SRS alone (P < .001). On final imaging, 36 of 37 patients (97.3%) treated by WBRT developed leukoencephalopathy (25% with grade 2; 70.8% with grade 3). Only 1 patient treated with SRS alone developed leukoencephalopathy., Conclusions: Risk of leukoencephalopathy in patients treated with SRS alone for brain metastases was significantly lower than that for patients treated with WBRT plus SRS. A prospective study is necessary to correlate these findings with neurocognition and quality of life. These data supplement existing reports regarding the differential effects of WBRT and SRS on normal brain structure and function., (Copyright © 2012 American Cancer Society.)

Over the last two decades, stereotactic radiosurgery (SRS) has become a mainstay in the management of arteriovenous malformations (AVMs) of the brain. An extensive collective experience has demonstrated that SRS is a minimally invasive technique that can produce excellent AVM obliteration rates with only a modest risk of permanent adverse radiation effects (AREs). Controversy remains regarding the optimal treatment approach for AVMs, with much of the debate centered upon the risk:benefit ratios of microsurgical resection versus SRS. Proponents of surgery suggest that for appropriate Spetzler-Martin grade AVMs microsurgery harbors minimal morbidity and immediate cure. In contrast, supporters of SRS argue that many AVMs cannot be treated by microsurgery with limited morbidity, and that despite the possibility of hemorrhage during the latency to obliteration, the risk profile of SRS is more favorable. Unfortunately, a randomized clinic trial comparing microsurgery and SRS is not likely, so clinicians and patients must use available data to make their own decisions. Much effort has been expended to identify factors associated with AREs, defining their impact and predicting which patients are likely to have complete AVM obliteration in the absence of new neurological deficits. Refinement in an AVM management algorithm on these bases should better educate clinicians and patients about risk profiles, improve patient selection for different treatment strategies, and increase the likelihood of good therapeutic outcomes. Herein, we give a definition to the term ARE and review the suspected mechanisms that lead to them., (Copyright © 2013 S. Karger AG, Basel.)

Object: 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., Methods: 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)., Results: 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., Conclusions: 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.