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Introduction/Purpose Historically, spinal dural arteriovenous fistulas (SDAVFs) have been treated with intradural ligation of the draining vein. While endovascular embolization can achieve durable occlusion in a subset of these patients, recent studies have demonstrated a superiority of microsurgical ligation. However, given that spinal angiography is essential in the workup of suspected SDAVFs, we and others have demonstrated the utility of an ‘endovascular-first’ approach to SDAVFs. One limiting factor to the success of endovascular therapies has been the reliability of casting and occluding the draining vein using Onyx. In contrast, we have observed that n-butyl-2-cyanoacrylate (nBCA) glue can readily penetrate and cast the fistula and vein. We therefore sought to compare the efficacy of nBCA and Onyx embolization in the treatment of SDAVFs. Material and Methods We performed a retrospective analysis of our endovascular database from 4/2007 to 4/2019 to identify patients treated for SDAVFs. We extracted demographic, clinical, treatment, and radiographic information data. We considered a ‘durable cure’ of the SDAVF to include complete obliteration of the fistula following endovascular treatment, demonstrated clinical improvement, and follow-up radiographic studies demonstrating improvement of spinal cord edema and flow voids on MRI/MRA and/or persistent obliteration on follow-up angiograms. We compared our results using Onyx and nBCA embolysate. Results We performed 40 endovascular treatments for SDAVFs in 38 patients. The embolysates utilized were Onyx without any other embolysate (22), NBCA without any other liquid embolysate (16), and a combination of nBCA and Onyx (2). For the 22 treatments in which Onyx was the only embolysate used, endovascular treatment resulted in a durable cure in 11 cases (50%) (mean follow-up 20.8 months). For 10 of these 22 (45.5%), a complete obliteration of the fistula with casting of the vein was not achieved and these patients were referred for microsurgical ligation. For 1 of these 22 treatments, a complete obliteration of the fistula was noted on immediate post-procedure angiography. However, 4.2 months after treatment, he was found to have a recurrence. For the 16 treatments in which nBCA was the only liquid embolysate used, endovascular treatment resulted in a complete obliteration of the fistula following treatment in all 16 (100%) patients. None of these patients underwent subsequent microsurgical treatment. Follow-up data were available for 13 of these patients (81.3%). Of these 13, all (100%) achieved a durable cure (mean follow-up 19.6 months) without clinical or radiographic recurrence. A durable cure was achieved more frequently in patients treated with nBCA (100%) relative to those treated with Onyx only (50%) (p Conclusion NBCA embolization of SDAVFs is superior to Onyx embolization. NBCA embolization is safe and effective for a subset of SDAVFs with results in this population comparable to microsurgical ligation. Disclosures J. Baranoski: None. J. Catapano: None. T. Cole: None. N. Majmundar: None. B. Hendricks: None. D. Wilkinson: None. A. See: None. D. Cavalcanti: None. B. Flores: None. A. Ducruet: None. F. Albuquerque: None.

Background Intracranial hemangiopericytomas (HPCs) are characterized by high recurrence rates and extracranial metastases. Radiotherapy provides an adjunct to surgery, but the timing of therapy and the patients most likely to benefit remain unclear. Methods A retrospective review of 20 patients with HPC treated at the University of Texas Southwestern Medical Center between 1985 and 2014 was conducted. Recurrence and metastasis rates along with overall survival (OS) were characterized based on therapeutic approach and tumor pathology using Kaplan-Meier and Cox regression analyses. Results The mean age was 45.6 years (range: 19–77). Gross total resection (GTR) was achieved in 13 patients, whereas 5 patients underwent subtotal resection. Median follow-up was 91.5 months (range: 8–357). The 5-, 10-, and 15-year recurrence-free survival (RFS) rates were 61, 41, and 20%, respectively. Six patients developed metastases at an average of 113 months (range: 42–231). OS at last follow-up was 80%. Importantly, immediate postoperative adjuvant radiotherapy (IRT) did not influence RFS compared with surgery alone or OS compared with delayed radiotherapy at the time of recurrence. Conclusion HPCs have high recurrence rates necessitating close follow-up. Surgery remains an important first step, but the timing of radiotherapy for optimal control and OS remains uncertain.

Encephalocele is a rare condition that consists of herniation of cerebral matter through openings of dura and skull. A majority of encephaloceles are congenital and manifest in childhood. We present a case of a 45-year-old man presenting with contralateral hemiparesis and found to have an extremely rare phenomenon of a symptomatic posttraumatic parietal intradiploic encephalocele (IE) manifesting 36 years following pediatric traumatic head injury. Computed tomography and magnetic resonance imaging confirmed herniation of brain tissue into the intradiploic space. Surgical treatment with reduction of the encephalocele achieved near resolution of preoperative hemiparesis on follow-up. The pathogenesis and a literature review of IE are discussed.

The treatment of intracranial aneurysms, whether surgical or endovascular, is associated with various types of potentially catastrophic procedure-related complications. These complications include intraprocedural rupture, thromboembolic events, coil migration or prolapse into the parent artery, and aneurysm recurrence that requires further management. The highest complication rates are for treatment of ruptured aneurysms, with intraprocedural rupture more common in endovascular techniques using balloon-assisted and stent-assisted coiling. Using imaging studies to carefully study the anatomic characteristics of the aneurysm and its relationship to the parent vessel can inform preoperative and intraoperative decision-making and treatment. Complications are likely to be more manageable with appropriate selection of treatment, awareness of potential complications, immediate recognition of complications, and familiarity with salvage and adjuvant techniques.

Spinal vascular malformations (SVMs) are a heterogeneous group that can cause acute, subacute, or chronic spinal cord dysfunction. The majority of the patients present to neurosurgical attention after a protracted course with severe neurological dysfunction. Spinal vascular lesions comprise approximately 3-4 % of all intradural spinal lesions. They are pathologically similar to their intracranial counterparts, but their clinical impact is often comparatively worse. Early, correct recognition of the pathology is mandatory to halt the progression of the disease and minimize permanent spinal cord injury. The first clinical observation of a SVM was published in 1890, but it was not until 1914 that the first successful surgical treatment of a spinal vascular malformation was reported. Intervention-either by microsurgical or endovascular means-aims to halt or reverse the progressive neurological deterioration by eliminating flow through the abnormal fistulous or nidal connections, and restoring normal spinal cord perfusion and intravascular pressures. In fact, complex spinal arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs) frequently require a multimodality approach that utilizes both microsurgery and endovascular embolization effectively. The goal of this review is to describe the various types of vascular malformations of the spine, their pathophysiology, clinical presentation, treatment strategies, and outcome. For purposes of discussion on the current manuscript, vascular malformations of the spine were divided into arteriovenous fistulas (AVFs) and arteriovenous malformations (AVMs). Spinal cord aneurysms are extremely rare, and the majority of the lesions that come to the neurosurgeon's attention are concomitant to a spinal AVM.

About 1,658,370 new cancer cases are expected to be diagnosed in the United States in 2015, and 589,430 Americans are expected to die of cancer. Despite those dreadful numbers, the 5-year survival rate for all cancers diagnosed in 2004 2010 was 68%, up from 49% in 1975 1977. The steady improvement in survival seen throughout those past 4 decades can be attributed to a combination of early diagnosis and better treatment modalities. Brain metastases occur in 20% 40% of patients with systemic cancer and are the most common type of intracranial tumor, outnumbering primary tumors by 10 to 1. They are multifocal in more than 70% of cases. Notwithstanding the improvements in survival in stage IV (metastatic) patients as a whole, the occurrence of brain metastases is often considered a sign of uncontrolled or treatment resistant disease and carries a dismal prognosis. As a case in point, the median overall survival is 1 2 months with corticosteroids, which can be extended to 6 months with whole brain radiation therapy (WBRT). The treatment algorithm for brain metastases typically involves some combination of surgical resection, radiotherapy, radiosurgery, and corticosteroids. With few exceptions, systemic therapies like chemotherapy are usually not an effective first-line treatment modality. The utility of the surgical management of single brain metastases was described by Patchell et al. in 1990. In this small, double-arm, randomized, prospective trial, 48 patients were randomized to either surgical removal of the brain tumor followed by WBRT (surgical group) or needle biopsy and WBRT (radiation group). Same-site recurrence was less frequent in the surgical group (20% vs. 52%). More importantly, the overall survival was significantly longer in the surgical group (median 40 weeks vs. 15 weeks in the radiation group) and those patients remained functionally independent longer (38 weeks vs. 8 weeks in the radiation group). When death from systemic causes was used as the survival end point, the differences between the surgical and radiation groups were not statistically significant. Twenty-five years after its publication, the first Patchell et al. randomized study remains one of the most cited articles on the theme, with more than 2100 indexed citations. Because most cases of brain metastases are multifocal, surgical resection is limited to only 10% 20% of the patients. In situations where surgical resection is not indicated or of limited benefit, WBRT has historically been the mainstay of treatment. The decision to use WBRT revolves around its impact on 3 interrelated components: 1) overall survival, 2) intracranial control, and 3) neurocognitive sequelae. While a large volume of retrospective reports support the effectiveness of WBRT on the management of brain metastases, there are no high-level

Objective Preoperative embolization may facilitate skull base meningioma resection, but its safety and efficacy in the Onyx era have not been investigated. In this retrospective cohort study, we evaluated the outcomes of preoperative embolization of skull base meningiomas using Onyx as the primary embolysate. Methods We queried an endovascular database for patients with skull base meningiomas who underwent preoperative embolization at our institution in 2007–2017. Patient, tumor, procedure, and outcome data were analyzed. Results Twenty-eight patients (28 meningiomas) underwent successful preoperative meningioma embolization. The mean patient age ± SD was 56 ± 13 years, and 18 patients (64%) were women. The mean tumor size was 49 cm3. There were 1, 2, or 3 arterial pedicles embolized in 21 cases (75%), 6 cases (21%), and 1 case (4%), respectively. The embolized pedicles included branches of the middle meningeal artery in 19 cases (68%), the internal maxillary artery in 8 cases (29%), the ascending pharyngeal artery in 2 cases (7%), and the posterior auricular, ophthalmic, occipital, and anterior cerebral arteries in 1 case each (4%). The embolysates used were Onyx alone in 20 cases (71%), n-butyl cyanoacrylate alone in 3 cases (11%), coils/particles and Onyx/n-butyl cyanoacrylate in 2 cases each (7%), and Onyx and coils in 1 case (4%). The median degree of tumor devascularization was 60%. Significant neurologic morbidity occurred in 1 patient (4%) who developed symptomatic peritumoral edema after Onyx embolization. Conclusions For appropriately selected skull base meningiomas supplied by dura mater–based arterial pedicles without distal cranial nerve supply, preoperative embolization with current embolysate technology affords substantial tumor devascularization with a low complication rate.

Effective treatment of cerebral arteriovenous malformations (AVMs) requires a multidisciplinary approach that appropriately applies the complementary modalities of microsurgical resection, endovascular embolization, and radiosurgery. Embolization is most commonly used as an adjunct to reduce the arterial supply to the AVM before surgery or radiosurgery. Additional indications for embolization include an attempt to achieve complete AVM obliteration, targeted treatment to eliminate high-risk features, and subtotal occlusion to palliate symptoms caused by an otherwise incurable AVM. In all cases, the risks and benefits of treatment must be weighed carefully when formulating a treatment strategy. For optimal management of cerebral AVMs, patients should have access to physicians experienced in open cerebrovascular surgery, endovascular embolization, and radiosurgery.

Over the past two decades, endovascular embolization has become a fundamental part of a multidisciplinary approach for the treatment of intracranial arteriovenous malformations (AVMs). Several embolic agents are now an intrinsic part of the neurointerventional armamentarium. However, none has represented as remarkable an improvement as the introduction of ethylene vinyl alcohol copolymer (EVOH). In conjunction with n-butyl cyanoacrylate (NBCA), EVOH has revolutionized the endovascular management of intracranial AVMs because of its ability to systematically deliver a sufficient volume of the embolic agent to the nidus and pedicles without extension into the venous drainage. The clinical decision to treat an AVM is facilitated by preoperative risk stratification; the first question to be addressed is whether to treat the AVM; and, if so, the second question is how to treat it. Endovascular EVOH embolization is primarily applied as an adjunct treatment to microsurgical resection or radiosurgery. Few cases are amenable to angiographic cure by embolization alone. The goal of this chapter is to describe the pertinent properties, endovascular techniques, and pitfalls for the endovascular management of intracranial AVMs using EVOH.

OBJECTIVEParaclinoid internal carotid artery (ICA) aneurysms frequently require temporary occlusion to facilitate safe clipping. Brisk retrograde flow through the ophthalmic artery and cavernous ICA branches make simple trapping inadequate to soften the aneurysm. The retrograde suction decompression (RSD), or Dallas RSD, technique was described in 1990 in an attempt to overcome some of those treatment limitations. A frequent criticism of the RSD technique is an allegedly high risk of cervical ICA dissection. An endovascular modification was introduced in 1991 (endovascular RSD) but no studies have compared the 2 RSD variations.METHODSThe authors performed a systematic review of MEDLINE/PubMed and Web of Science and identified all studies from 1990–2016 in which either Dallas RSD or endovascular RSD was used for treatment of paraclinoid aneurysms. A pooled analysis of the data was completed to identify important demographic and treatment-specific variables. The primary outcome measure was defined as successful aneurysm obliteration. Secondary outcome variables were divided into overall and RSD-specific morbidity and mortality rates.RESULTSTwenty-six RSD studies met the inclusion criteria (525 patients, 78.9% female). The mean patient age was 53.5 years. Most aneurysms were unruptured (56.6%) and giant (49%). The most common presentations were subarachnoid hemorrhage (43.6%) and vision changes (25.3%). The aneurysm obliteration rate was 95%. The mean temporary occlusion time was 12.7 minutes. Transient or permanent morbidity was seen in 19.9% of the patients. The RSD-specific complication rate was low (1.3%). The overall mortality rate was 4.2%, with 2 deaths (0.4%) attributable to the RSD technique itself. Good or fair outcome were reported in 90.7% of the patients.Aneurysm obliteration rates were similar in the 2 subgroups (Dallas RSD 94.3%, endovascular RSD 96.3%, p = 0.33). Despite a higher frequency of complex (giant or ruptured) aneurysms, Dallas RSD was associated with lower RSD-related morbidity (0.6% vs 2.9%, p = 0.03), compared with the endovascular RSD subgroup. There was a trend toward higher mortality in the endovascular RSD subgroup (6.4% vs 3.1%, p = 0.08). The proportion of patients with poor neurological outcome at last follow-up was significantly higher in the endovascular RSD group (15.4% vs 7.2%, p < 0.01).CONCLUSIONSThe treatment of paraclinoid ICA aneurysms using the RSD technique is associated with high aneurysm obliteration rates, good long-term neurological outcome, and low RSD-related morbidity and mortality. Review of the RSD literature showed no evidence of a higher complication rate associated with the Dallas technique compared with similar endovascular methods. On a subgroup analysis of Dallas RSD and endovascular RSD, both groups achieved similar obliteration rates, but a lower RSD-related morbidity was seen in the Dallas technique subgroup. Twenty-five years after its initial publication, RSD remains a useful neurosurgical technique for the management of large and giant paraclinoid aneurysms.

OBJECTIVELiquid embolic agents have revolutionized endovascular management of arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs). Nonetheless, since 2005, the US FDA has received more than 100 reports of microcatheter breakage or entrapment related to Onyx embolization, including 9 deaths. In 2014, the Apollo detachable-tip microcatheter became the first of its kind available in the US. Since then, few reports on its safety have been published.METHODSThe authors conducted a retrospective review of endovascular cases by searching the patient databases at 2 tertiary cerebrovascular centers (Barrow Neurological Institute and University of Pittsburgh Medical Center). Patients who underwent endovascular embolization of an AVM or AVF using the Apollo microcatheter were identified. Patient demographics and lesion characteristics were collected. The authors analyzed Apollo-specific endovascular variables, such as number of microcatheterizations, sessions, and pedicles embolized; microcatheter tip detachment status; obliteration rate; and endovascular- and microcatheter-related morbidity and mortality.RESULTSFrom July 2014 to October 2016, a total of 177 embolizations using the Apollo microcatheter were performed in 61 patients (mean age 40.3 years). The most frequent presentation was hemorrhage (22/61, 36.1%). Most lesions were AVMs (51/61, 83.6%; mean diameter 30.6 mm). The mean Spetzler-Martin grade was 2.4. Thirty-nine (76.5%) of 51 patients with AVMs underwent resection. Microcatheterization was successful in 172 pedicles. Most patients (50/61, 82%) underwent a single embolization session. The mean number of pedicles per session was 2.5 (range 1–7). Onyx-18 was used in 103 (59.9%), N-butyl cyanoacrylate (NBCA) in 44 (25.6%), and Onyx-34 in 25 (14.5%) of the 172 embolizations. In 45.9% (28/61) of the patients, lesion obliteration of 75% or greater was achieved. Tip detachment occurred in 19.2% (33/172) of microcatheters. Fifty-three (86.9%) of the 61 patients who underwent embolization with the Apollo microcatheter had good functional outcomes (modified Rankin Scale score 0–2). No unintended microcatheter fractures or related morbidity was observed. One patient died of intraprocedural complications unrelated to microcatheter selection. In the univariate analysis, microcatheter tip detachment (p = 0.12), single embolized pedicles (p = 0.12), and smaller AVM nidus diameter (p = 0.17) correlated positively with high obliteration rates (> 90%). In the multivariate analysis, microcatheter tip detachment was the only independent variable associated with high obliteration rates (OR 9.5; p = 0.03).CONCLUSIONSThe use of the Apollo detachable-tip microcatheter for embolization of AVMs and AVFs is associated with high rates of successful catheterization and obliteration and low rates of morbidity and mortality. The microcatheter was retrieved in all cases, even after prolonged injections in distal branch pedicles, often with significant reflux. This study represents the largest case series on the application of the Apollo microcatheter for neurointerventional procedures.

Occlusion of the basilar artery can be treated with endovascular thrombectomy, although the results have not been well studied. Persistent fetal cerebrovascular anatomy can lead to unusual presentation of carotid atherosclerotic disease and can be a barrier to successful mechanical thrombectomy if not recognized. This case presents a rare persistent carotico-basilar anastomosis which resulted in basilar occlusion via the persistent hypoglossal artery and coincident absence of contralateral vertebral arterial access due to a left vertebral artery terminating in the left posterior inferior cerebellar artery. Preoperative recognition of this anatomy afforded by review of cross-sectional imaging was critical to success during this emergent procedure.

Occlusion of the basilar artery can be treated with endovascular thrombectomy, although the results have not been well studied. Persistent fetal cerebrovascular anatomy can lead to unusual presentation of carotid atherosclerotic disease and can be a barrier to successful mechanical thrombectomy if not recognized. This case presents a rare persistent carotico-basilar anastomosis which resulted in basilar occlusion via the persistent hypoglossal artery and coincident absence of contralateral vertebral arterial access due to a left vertebral artery terminating in the left posterior inferior cerebellar artery. Preoperative recognition of this anatomy afforded by review of cross-sectional imaging was critical to success during this emergent procedure.

Infectious intracranial aneurysms (IIAs) account for approximately 15 % of all pediatric intracranial aneurysms. Histologically, they are pseudoaneurysms that develop in response to an inflammatory reaction within the adventitia and muscularis layers, ultimately resulting in disruption of both the internal elastic membrane and the intima. The majority of pediatric IIAs are located within the anterior circulation, and they can be multiple in 15–25 % of cases. The most common presentation for an IIA is intracerebral and/or subarachnoid hemorrhage. In children with a known diagnosis of infective endocarditis who develop new neurological manifestations, it is imperative to exclude the existence of an IIA. The natural history of untreated infectious aneurysms is ominous; they demonstrate a high incidence of spontaneous rupture. High clinical suspicion, prompt diagnosis, and adequate treatment are of paramount importance to prevent devastating neurological consequences. The prompt initiation of intravenous broad-spectrum antibiotics represents the mainstay of treatment. Three questions should guide the management of pediatric patients with IIAs: (a) aneurysm rupture status, (b) the presence of intraparenchymal hemorrhage or elevated intracranial pressure, and (c) relationship of the parent vessel to eloquent brain tissue. Those three questions should orient the treating physician into either antibiotic therapy alone or in combination with microsurgical or endovascular interventions. This review discusses important aspects of the epidemiology, the diagnosis, and the management of IIAs in the pediatric population.

OBJECT Resection of brainstem cavernous malformations (BSCMs) may reduce the risk of stepwise neurological deterioration secondary to hemorrhage, but the morbidity of surgery remains high. Diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) are neuroimaging techniques that may assist in the complex surgical planning necessary for these lesions. The authors evaluate the utility of preoperative DTI and DTT in the surgical management of BSCMs and their correlation with functional outcome. METHODS A retrospective review was conducted to identify patients who underwent resection of a BSCM between 2007 and 2012. All patients had preoperative DTI/DTT studies and a minimum of 6 months of clinical and radiographic follow-up. Five major fiber tracts were evaluated preoperatively using the DTI/DTT protocol: 1) corticospinal tract, 2) medial lemniscus and medial longitudinal fasciculus, 3) inferior cerebellar peduncle, 4) middle cerebellar peduncle, and 5) superior cerebellar peduncle. Scores were applied according to the degree of distortion seen, and the sum of scores was used for analysis. Functional outcomes were measured at hospital admission, discharge, and last clinic visit using modified Rankin Scale (mRS) scores. RESULTS Eleven patients who underwent resection of a BSCM and preoperative DTI were identified. The mean age at presentation was 49 years, with a male-to-female ratio of 1.75:1. Cranial nerve deficit was the most common presenting symptom (81.8%), followed by cerebellar signs or gait/balance difficulties (54.5%) and hemibody anesthesia (27.2%). The majority of the lesions were located within the pons (54.5%). The mean diameter and estimated volume of lesions were 1.21 cm and 1.93 cm3, respectively. Using DTI and DTT, 9 patients (82%) were found to have involvement of 2 or more major fiber tracts; the corticospinal tract and medial lemniscus/medial longitudinal fasciculus were the most commonly affected. In 2 patients with BSCMs without pial presentation, DTI/DTT findings were important in the selection of the surgical approach. In 2 other patients, the results from preoperative DTI/DTT were important for selection of brainstem entry zones. All 11 patients underwent gross-total resection of their BSCMs. After a mean postoperative follow-up duration of 32.04 months, all 11 patients had excellent or good outcome (mRS Score 0–3) at the time of last outpatient clinic evaluation. DTI score did not correlate with long-term outcome. CONCLUSIONS Preoperative DTI and DTT should be considered in the resection of symptomatic BSCMs. These imaging studies may influence the selection of surgical approach or brainstem entry zones, especially in deep-seated lesions without pial or ependymal presentation. DTI/DTT findings may allow for more aggressive management of lesions previously considered surgically inaccessible. Preoperative DTI/DTT changes do not appear to correlate with functional postoperative outcome in long-term follow-up.

Supratentorial arteriovenous malformations in eloquent territories can be difficult to resect. This video presents the treatment of a patient with a symptomatic 3-cm arteriovenous malformation in the left motor strip. At the authors’ institution, per the surgeon’s discretion, preoperative angiography is performed to evaluate the need for preoperative embolization. Multimodality treatment reduced the microsurgical risk by allowing early occlusion of a draining vein, by decreasing overall intraoperative hemorrhage, and by allowing minimal pial dissection in the deep aspect of the arteriovenous malformation that abutted the corticospinal tract. The choice of embolysate was an additional nuance of the embolization.The video can be found here: https://youtu.be/HWZ0RjgPEXg.

Occlusion of the basilar artery can be treated with endovascular thrombectomy, although the results have not been well studied. Persistent fetal cerebrovascular anatomy can lead to unusual presentation of carotid atherosclerotic disease and can be a barrier to successful mechanical thrombectomy if not recognized. This case presents a rare persistent carotico–basilar anastomosis which resulted in basilar occlusion via the persistent hypoglossal artery and coincident absence of contralateral vertebral arterial access due to a left vertebral artery terminating in the left posterior inferior cerebellar artery. Preoperative recognition of this anatomy afforded by review of cross-sectional imaging was critical to success during this emergent procedure.

Introduction Atypical meningiomas (World Health Organization [WHO] grade II) represent a therapeutic challenge given their high recurrence rate and greater mortality compared with WHO grade I meningiomas. Traditionally, treatment has entailed attempts at gross total resection with radiation therapy reserved for residual disease or recurrences. Methods We retrospectively reviewed our patient database of atypical meningioma (AM) patients over the past 10 years to assess surgical and radiotherapeutic treatments administered, treatment-related complications, radiographic-clinical progression after treatment, and mortality. We identified 45 patients with AMs and excluded 2 patients with incomplete hospital records. Results The average age of our patients was 59.7 years. Forty-three AM patients underwent a total of 62 surgeries. Thirty patients underwent one initial surgical resection; 8 patients underwent a second resection for recurrence; 4 patients underwent 3 resections; and 1 patient underwent 4 resections for recurrences. The rate of postoperative complication was 12.9% (8/62). Five patients had postoperative wound infections requiring treatment, and 1 patient had a postoperative hematoma requiring surgical evacuation. There was 1 case of wound breakdown in a patient with a previously irradiated scalp and 1 case of lower-extremity venous thrombosis. Clinical follow-up ranged from 11–120 months with average follow-up of 43 months and median follow-up of 65 months. Nineteen patients (44%) developed clinical-radiographic evidence of recurrence at an average of 32.4 months after surgical resection. Of the recurrences, 12 were treated with repeat surgery and radiation therapy, 3 were treated with radiation therapy alone, and 2 with surgery alone. Radiation therapy included Gamma Knife (GK), CyberKnife (CK), intensity-modulated radiation therapy (IMRT), or some combination of these. There was one case of symptomatic radiation necrosis (1/15 or 6.6%). The survival rate at last follow-up of our patient cohort was 95.3%. Conclusions Given their high rates of recurrence, AMs require close clinical follow-up and an individualized treatment strategy. Reoperation, radiotherapy, or combination therapy can be effective strategies at managing disease progression while minimizing treatment-related morbidity. Treatment planning that attempts to anticipate future therapies in the form of further surgery or radiotherapy may improve clinical outcomes in these patients. Seventeen patients underwent adjuvant radiation therapy: 7 patients with intensity-modulated radiation therapy (IMRT), 4 patients with Gamma Knife (GK), and 2 with CyberKnife (CK). Four patients underwent multiple treatments.

Intracranial or brain arteriovenous malformations (BAVMs) are some of the most interesting and challenging lesions treated by the cerebrovascular neurosurgeon. It is generally believed that the combination of BAVMs and intracranial aneurysms (IAs) is associated with higher hemorrhage rates at presentation and higher rehemorrhage rates and thus with a more aggressive course and natural history. There is wide variation in the literature on the prevalence of BAVM-associated aneurysms (range 2.7%–58%), with 10%–20% being most often cited in the largest case series. The risk of intracranial hemorrhage in patients with unruptured BAVMs and coexisting IAs has been reported to be 7% annually, compared with 2%–4% annually for those with BAVM alone. Several different classification systems have been applied in an attempt to better understand the natural history of this combination of lesions and implications for treatment. Independent of the classification used, it is clear that a few subtypes of aneurysms have a direct hemodynamic correlation with the BAVM itself. This is exemplified by the fact that the presence of a distal flow-related or an intranidal aneurysm appears to be associated with an increased hemorrhage risk, when compared with an aneurysm located on a vessel with no direct supply to the BAVM nidus. Debate still exists regarding the etiology of the association between those two vascular lesions, the subsequent implications for patients’ risk of hemorrhagic stroke, and finally the determination of which patients warrant treatment and when. The ultimate goals of the treatment of a BAVM associated with an IA are to prevent hemorrhage, avoid stepwise neurological deterioration, and eliminate the mortality risk associated with recurrent hemorrhagic events. The treatment is only justifiable if the risks associated with an intervention are lower than or equivalent to the long-term risks of disability or mortality caused by the lesion itself. When faced with this difficult decision, a few questions need to be answered by the treating neu-rosurgeon: What is the mode of presentation? What is the symptomatic lesion? Which one of the lesions bled? What is the relationship between the BAVM and IA? Is it possible to safely treat both BAVM and IA? The objective of this review is to discuss the demographics, natural history, classification, and strategies for management of BAVMs associated with IAs.

BACKGROUND: Specific morphological factors contribute to the hemodynamics of the anterior communicating artery (AComA). No study has examined the role of the A2 segment on AComA aneurysm presence and rupture. OBJECTIVE: To examine the possibility that the ratio between A1 and A2 segments (A1-2 ratio) represents an independent risk factor for presence and rupture of AComA aneurysms (AComAAs). METHODS: A retrospective review of an institutional aneurysm database was performed; patients with ruptured and unruptured AComAAs were identified. Two control groups were selected: group A (posterior circulation aneurysms) and group B (patients without intracranial aneurysms or other vascular malformations). Measurements of A1 and A2 diameters were obtained from digital subtraction angiography (64.1% of 3-D rotational digital subtraction angiography), and the A1-2 ratio calculated. RESULTS: From January 2009 to April 2011, 156 patients were identified (52 AComAAs, 54 control group A, and 50 control group B). Mean age at the time of presentation was 56.09 years. Compared with both control groups, patients with AComAAs had greater A1 diameter (P < .01) and A1-2 ratio (P < .001) and smaller A2 diameter (P < .01). The A1-2 ratio correlated positively with the presence of AComAAs (P < .001). Ruptured AComAAs were smaller than unruptured ones (5.91 mm vs 9.25 mm, P = .02) and associated with a higher A1-2 Ratio (P = .02). The presence of a dominant A1 did not predict AComAA rupture (P = .15). The A1-2 ratio correlated positively with the presence of ruptured AComAAs (P = .04). CONCLUSION: A1-2 ratio correlates positively with the presence and rupture of AComAAs and may facilitate treatment decision in cases of small, unruptured AComAAs.

Cavernous sinus meningiomas (CSMs) are challenging lesions for the skull base neurosurgeon to manage given their close association with cranial nerves II–VI and the internal carotid artery. In the 1980s and early 1990s, with advancements in microsurgical techniques, increasing knowledge of the relevant microsurgical neuroanatomy, and the advent of advanced skull base surgical approaches, the treatment of CSMs involved attempts at gross-total resection (GTR). Initial fervor for a surgical cure waned, however, as skull base neurosurgeons demonstrated the limits of complete resection in this region, the ongoing issue of potential tumor recurrences, and the unacceptably high cranial nerve and vascular morbidity associated with this strategy. The advent of radiosurgery and its documented success for tumor growth control and limited morbidity in cavernous lesions has helped to shift the treatment goals for CSMs from GTR to tumor control and symptom relief while minimizing treatment- and lesion-associated morbidity. The authors review the relevant microanatomy of the cavernous sinus with anatomical and radiographic correlates, as well as the various treatment options. A modernized, multimodality treatment algorithm to guide management of these lesions is proposed.

Foramen magnum meningiomas (FMMs) are slow growing, most often intradural and extramedullary tumors that pose significant challenges to the skull base neurosurgeon. The indolent clinical course of FMMs and their insidious onset of symptoms are important factors that contribute to delayed diagnosis and relative large size at the time of presentation. Symptoms are often produced by compression of surrounding structures (such as the medulla oblongata, upper cervical spinal cord, lower cranial nerves, and vertebral artery) within a critically confined space. Since the initial pathological description of a FMM in 1872, various surgical approaches have been described with the aim of achieving radical tumor resection. The surgical treatment of FMMs has evolved considerably over the last 4 decades due to the progress in microsurgical techniques and development of a multitude of skull base approaches. Posterior and posterolateral FMMs can be safely resected via a standard midline suboccipital approach. However, controversy still exits regarding the optimal management of anterior or anterolateral lesions. Independently of technical variations and the degree of bone removal, all modern surgical approaches to the lower clivus and anterior foramen magnum derive from the posterolateral (or far-lateral) craniotomy originally described by Roberto Heros and Bernard George. This paper is a review of the surgical management of FMMs, with emphasis on the far-lateral approach and its variations. Clinical presentation, imaging findings, important neuroanatomical correlations, recurrence rates, and outcomes are discussed.

Pseudomonas aeruginosa meningitis is an uncommon complication of neurosurgical procedures or head trauma. Here, a case of infectious mid basilar artery aneurysm from Pseudomonas meningitis, and its angiographic remission from timely antibiotic therapy, is reported.