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OBJECTIVE Morphological and angioarchitectural features of cerebral arteriovenous malformations (AVMs) have been widely described and associated with outcomes; however, few studies have conducted a quantitative analysis of AVM flow. The authors examined brain AVM flow and transit time on angiograms using direct visual analysis and a computer-based method and correlated these factors with the obliteration response after Gamma Knife radiosurgery. METHODS A retrospective analysis was conducted at a single institution using a prospective registry of patients managed from January 2013 to December 2019: 71 patients were analyzed using a visual method of flow determination and 38 were analyzed using a computer-based method. After comparison and validation of the two methods, obliteration response was correlated to flow analysis, demographic, angioarchitectural, and dosimetric data. RESULTS The mean AVM volume was 3.84 cm3 (range 0.64–19.8 cm3), 32 AVMs (45%) were in critical functional locations, and the mean margin radiosurgical dose was 18.8 Gy (range 16–22 Gy). Twenty-seven AVMs (38%) were classified as high flow, 37 (52%) as moderate flow, and 7 (10%) as low flow. Complete obliteration was achieved in 44 patients (62%) at the time of the study; the mean time to obliteration was 28 months for low-flow, 34 months for moderate-flow, and 47 months for high-flow AVMs. Univariate and multivariate analyses of factors predicting obliteration included AVM nidus volume, age, and flow. Adverse radiation effects were identified in 5 patients (7%), and 67 patients (94%) remained free of any functional deterioration during follow-up. CONCLUSIONS AVM flow analysis and categorization in terms of transit time are useful predictors of the probability of and the time to obliteration. The authors believe that a more quantitative understanding of flow can help to guide stereotactic radiosurgery treatment and set accurate outcome expectations.

Purpose After developing a protocol for evaluating, diagnosing, and treating postoperative endocrinopathy both during the hospitalization and during the immediate discharge period following resection of pituitary adenomas, we sought to assess the impact of this protocol on quality outcomes. Methods An IRB-exempt, quality improvement initiated, Health Insurance Portability and Accountability Act (HIPAA)-compliant retrospective comparison of a pre-and-post-protocol cohort of all patients undergoing endoscopic endonasal resection of pituitary adenomas at NYU Langone Medical Center from January 2013 to December 2018. Demographic characteristics of the patients and their tumors with their postoperative outcomes were recorded. Quality outcomes regarding number of laboratory studies sent, rate of diabetes insipidus, length of stay, and readmission rate were also recorded. Statistical analysis was performed between the pre- and post-protocol groups. Results There was a significant reduction in laboratory studies sent per patient (55.66 vs. 18.82, p Conclusion Implementation of a postoperative management protocol results in a more efficient diagnosis and management of endocrinopathy after pituitary adenoma surgery which translates to decreased cost.

Background Postoperative prophylactic antibiotic usage for endoscopic skull base surgery varies based on the institution as evidence-based guidelines are lacking. The purpose of this study is to determine whether discontinuing postoperative prophylactic antibiotics in endoscopic endonasal cases led to a difference in central nervous system (CNS) infections, multi-drug resistant organism (MDRO) infections, or other postoperative infections. Methods This quality improvement study compared outcomes between a retrospective cohort (from September 2013 to March 2019) and a prospective cohort (April 2019 to June 2019) after adopting a protocol to discontinue prophylactic postoperative antibiotics in patients who underwent endoscopic endonasal approaches (EEAs). Our primary end points of the study included the presence of postoperative CNS infection, Clostridium difficile (C. diff), and MDRO infections. Results A total of 388 patients were analyzed, 313 in the pre-protocol group and 75 in the post-protocol group. There were similar rates of intraoperative cerebrospinal fluid leak (56.9 vs. 61.3%, p = 0.946). There was a statistically significant decrease in the proportion of patients receiving IV antibiotics during their postoperative course (p = 0.001) and those discharged on antibiotics (p = 0.001). There was no significant increase in the rate of CNS infections in the post-protocol group despite the discontinuation of postoperative antibiotics (3.5 vs. 2.7%, p = 0.714). There was no statistically significant difference in postoperative C. diff (0 vs. 0%, p = 0.488) or development of MDRO infections (0.3 vs 0%, p = 0.624). Conclusion Discontinuation of postoperative antibiotics after EEA at our institution did not change the frequency of CNS infections. It appears that discontinuation of antibiotics after EEA is safe.

Objective: The purpose of this report is to review intracranial arteriovenous malformations, present strategies for the evaluation and selection of optimal treatment modalities, and to discuss factors important to formulating a successful treatment plan. Methods: The authors performed a critical literature review in order to highlight recent and classic studies about intracranial arteriovenous malformations. Results: Recent advances in diagnostic techniques, microsurgery, endovascular therapy, and stereotactic radiosurgery have significantly improved the treatment outcome of vascularmalformations of the central nervous system. In patients who are minimally symptomatic, in normal neurologic condition, or whose treatment risk is high, not recommending any treatment can be an excellent viable option. For the others, microsurgery, endovascular embolization, and stereotacticradiosurgery offer complementary advantages and improve the chances of a lifetime cure. Conclusion: A thorough knowledge of the natural history ofintracranial arteriovenous malformations is fundamental to the treatment decision making process. A multidisciplinary team approach with the neurosurgeon taking a leading role is as well essential for a successful intracranial arteriovenous malformation management.

There is a consensus that most unruptured intracranial aneurysms can be treated with acceptably low morbidity and mortality. However, some studies recently reported postoperative cognitive impairment, suggesting that it could be attributableto neurosurgical clipping. The goal of this report is to review and discuss aspects referring to cognitive function and neurosurgical repair in patients with unruptured intracranial aneurysms.

Background Neurovascular training models include animal models, synthetics, or computer simulation. In vivo models are expensive and require significant resources. Synthetic/computer models do not reflect the elasticity of fresh vessels. We describe an endovascular and microsurgical training model using a chicken thigh/leg. Methods A total of 20 chicken thigh/leg models were obtained. Angiography was used to understand the anatomy. Proximal cannulation with a 5-French catheter was achieved and connected to a hemostatic valve with a pump to simulate pulsatile flow. Aneurysms were created at the thigh-leg junction. For clipping training, 3 types of aneurysms were created to reproduce anatomy seen in middle cerebral, anterior communicating, and posterior communicating aneurysms. Results The average cost per specimen was $1.70 ± $0.30. The diameter of the proximal femoral artery was 2.4 mm ± 0.2 mm. The length from the proximal femoral artery to the aneurysm was 9.5 cm ± 0.7 cm. Distal catheterization was successful in all cases (n = 6). Successful deployment of coils and a stent was achieved under fluoroscopic guidance. Gross oversizing of coils and other mistakes led to aneurysm rupture. Each examiner performed an exploration of the pulsatile aneurysm, application and reapplication of a variety of clips, and then the final inspection of branching vessels to confirm patency. Conclusions The chicken thigh/leg model provides training opportunities in microsurgical suturing, endovascular techniques for aneurysm obliteration, and microsurgical reconstruction of aneurysms. It combines affordability, time efficiency, and reproducibility. Further studies measuring improvement in technical aneurysm management and comparison with other training models are warranted.

The incidence of concomitant carotid artery stenosis and unruptured intracranial aneurysms (UIAs) has been reported at between 0.5% and 5%. In these patients, treatment strategies must balance the risk of ischemic stroke with the risk of aneurysmal rupture. Several studies have addressed the natural course of UIAs in the setting of carotid revascularization; however, the final recommendations are not uniform. The purpose of this study was to review our institutional experience with concomitant UIAs and carotid artery stenosis.We performed a retrospective review of all patients with carotid artery stenosis who underwent carotid artery endarterectomy (CEA) or carotid artery stenting (CAS) at our institution between 2003 and 2010. Only patients with preoperative imaging demonstrating intracranial circulation were included. Charts were reviewed for patients' demographic and clinical data, duration of follow-up, and aneurysm size and location. Patients were stratified into 2 groups: carotid artery stenosis with unruptured intracranial aneurysm (CS/UIA) and carotid artery stenosis without intracranial aneurysm (CS).Three hundred five patients met the inclusion criteria and had a total of 316 carotid procedures (CAS or CEA) performed. Eleven patients were found to have UIAs (3.61%) prior to carotid revascularization. Male and female prevalence was 2.59% and 5.26% (P = 0.22), respectively. Patients' demographics did not differ significantly between the 2 groups. The average aneurysm size was 3.25 ± 2.13 mm, and the most common location was the cavernous segment of the internal carotid artery. No patient in the study had aneurysm rupture, and the mean follow-up time was 26.5 months for the CS/UIA group.Concomitant carotid artery stenosis and UIAs is a rare entity. Carotid revascularization does not appear to increase the risk of rupture for small aneurysms (10 mm) in the midterm. Although not statistically significant, there was a higher incidence of aneurysms found in females in our patient population.

Background Giant intracranial artery aneurysms (GIAAs) are often not amenable to neurosurgical clipping or endovascular coiling. Extracranial-intracranial (EC-IC) bypass, a procedure that has been essentially abandoned for the treatment of intracranial ischemic disease, followed by parent vessel occlusion, is often successful in treating these aneurysms. Vascular surgeons should be familiar with this operation, especially in centers with neurosurgical capability. Methods A retrospective review of patients treated from 1990 to 2010 at New York University Medical Center was performed. Office and hospital records of all patients identified were reviewed with attention to the age and sex of the patient, presenting symptoms, preoperative testing, procedure performed, type of bypass conduit, graft patency, intraoperative and postoperative complications, length of follow-up, and overall outcome. EC-IC bypass was performed using a graft of great saphenous vein (GSV) or radial artery (RA). The vascular surgeon harvested the vascular conduit, tunneled the graft, and performed the extracranial anastomosis, and the intracranial anastomosis was performed by the neurosurgeon. Results A total of 36 patients (14 men, 22 women) underwent 37 EC-IC bypasses with 34 GSV and three RA grafts. The median age was 57 years (interquartile range, 49-66 years), and the median follow-up was 53 months (interquartile range, 29-77 months). Aneurysm location was the internal carotid artery in 30 patients, the basilar artery in three, and the middle cerebral artery in four. All 37 aneurysms were excluded from the cerebral circulation, with 33 grafts remaining patent at follow-up, as determined by serial cerebral or magnetic resonance angiogram. At follow-up, 33 of 34 of the GSV grafts (88%) and three of three (100%) of the RA grafts were patent. There were two deaths (5.6%), despite patent grafts. Postoperative graft occlusion led to homonymous hemianopsia in one patient and temporary hemiparesis in another (5.6%). Graft occlusions were asymptomatic in two patients. Conclusions EC-IC bypass is a safe and effective treatment for GIAAs, with acceptable rates of morbidity (5.6%), mortality (5.6%), and graft patency (89.2%). We suggest that the technique described in this report should be routinely used for treatment of GIAAs in centers where neurosurgery and vascular surgery services are available and should be considered a standard procedure in the armamentarium of the vascular surgeon.

Background Stereotactic radiosurgery is an effective treatment modality for small arteriovenous malformations (AVMs) of the brain. For larger AVMs, the treatment dose is often lowered to reduce potential complications, but this decreases the likelihood of cure. One strategy is to divide large AVMs into smaller anatomic volumes and treat each volume separately. Objective To prospectively assess the long-term efficacy and complications associated with staged-volume radiosurgical treatment of large, symptomatic AVMs. Methods Eighteen patients with AVMs larger than 15 mL underwent prospective staged-volume radiosurgery over a 13-year period. The median AVM volume was 22.9 mL (range, 15.7-50 mL). Separate anatomic volumes were irradiated at 3- to 9-month intervals (median volume, 10.9 mL; range, 5.3-13.4 mL; median marginal dose, 15 Gy; range, 15-17 Gy). The AVM was divided into 2 volumes in 10 patients, 3 volumes in 5 patients, and 4 volumes in 3 patients. Seven patients underwent retreatment for residual disease. Results Actuarial rates of complete angiographic occlusion were 29% and 89% at 5 and 10 years. Five patients (27.8%) had a hemorrhage after radiosurgery. Kaplan-Meier analysis of cumulative hemorrhage rates after treatment were 12%, 18%, 31%, and 31% at 2, 3, 5, and 10 years, respectively. One patient died after a hemorrhage (5.6%). Conclusion Staged-volume radiosurgery for AVMs larger than 15 mL is a viable treatment strategy. The long-term occlusion rate is high, whereas the radiation-related complication rate is low. Hemorrhage during the lag period remains the greatest source of morbidity and mortality.

Object. The goal of this study was to determine the relationship between aneurysm size and the volume of subarachnoid hemorrhage (SAH). Methods. One hundred consecutive patients who presented with acute SAH, which was diagnosed on the basis of a computerized tomography (CT) scan within 24 hours postictus and, subsequently, confirmed to be aneurysmal in origin by catheter angiography, were included in this study. The data were collected prospectively in 32 patients and retrospectively in 68. The volume of SAH on the admission CT scan was scored in a semiquantitative manner from 0 to 30, according to a previously published method. The mean aneurysm size was 8.3 mm (range 1–25 mm). The mean SAH volume score was 15 (range 0–30). Regression analysis revealed that a smaller aneurysm size correlated with a more extensive SAH (r2 = 0.23, p < 0.0001). Other variables including patient sex and age, intraparenchymal or intraventricular hemorrhage, multiple aneurysms, history of hypertension, and aneurysm location were not statistically associated with a larger volume of SAH. Conclusions. Smaller cerebral aneurysm size is associated with a larger volume of SAH. The pathophysiological basis for this correlation remains speculative.

OBJECTIVE: To minimize the risks associated with treating cortical cerebral arteriovenous malformations (AVMs), we developed a technique combining functional imaging and cerebral angiography. The functional loci obtained by performing magnetoencephalography (MEG) are projected onto stereoscopic pairs of a stereotactically derived digital subtraction angiogram. The result is a simultaneous three-dimensional perspective of the angioarchitecture of an AVM and its relationship to the sensorimotor cortex. METHODS: Eight patients underwent multimodality brain imaging, including magnetic resonance imaging, functional mapping via MEG, and stereotactic angiography using a modified Compass fiducial system (Compass International, Rochester, MN). The coordinates derived by performing MEG were superimposed onto stereotactic, stereoscopic, angiographic pairs using custom-made distortion correction and coordinate transfer software. RESULTS: The magnetoencephalographic angiogram allowed simultaneous viewing of the angioarchitecture of the AVM nidus, the feeding vessels, and the draining veins and their relationship to the normal cerebral vasculature and functional cortex. This imaging technique was particularly valuable in identifying en passant vessels that supplied functional cortex and was used during the treatment of these lesions. CONCLUSION: The techniques of MEG and cerebral angiography were combined to provide simultaneous viewing of both modalities in a three-dimensional perspective. This technique can aid in risk stratification in the management of patients with cerebral AVMs. In addition, this technique can facilitate the selective targeting of vessels, thus potentially reducing the risks associated with embolization of these formidable lesions.

Background and Purpose— Although there is generally thought to be a 2% to 4% per annum rupture risk for brain arteriovenous malformations (bAVMs), there is no way to estimate risk for an individual patient. Methods— In this retrospective study, patients were eligible who had nidiform bAVMs and underwent detailed pretreatment diagnostic cerebral angiography at our medical center from 1996 to 2006. All patients had superselective microcatheter angiography, and films were reviewed for the purpose of this project. Patient demographics, clinical presentation, and angioarchitectural characteristics were analyzed. A univariate analysis was performed, and angioarchitectural features with potential physiological significance that showed at least a trend toward significance were added to a multivariate logistic regression model. Results— One hundred twenty-two bAVMs met criteria for study entry. bAVMs with single venous drainage anatomy were more likely to present with hemorrhage. In addition, patients with multiple draining veins and a venous stenosis reverted to a risk similar to those with 1 draining vein, whereas those with multiple draining veins and without stenosis had diminished association with hemorrhage presentation. Those bAVMs with associated aneurysms were more likely to present with hemorrhage. These findings were robust in both univariate and multivariate models. Conclusions— The results of this article lead to the first physiological, internally consistent model of individual bAVM hemorrhage risk, where 1 draining vein, venous stenosis, and associated aneurysms increase risk.

BACKGROUND Hearing loss after intracranial and spinal procedures involving cerebrospinal fluid loss is rarely reported in the literature. We report a patient who suffered from delayed hearing loss after cerebrospinal fluid shunting that improved after revising the shunt to a higher-pressure valve. CASE DESCRIPTION A 32-year-old woman presented with bilateral hearing loss 4 years after ventriculoperitoneal shunting for communicating hydrocephalus. Her otologic work-up revealed sensorineural hearing loss. In an attempt to improve her hearing, 6 years after the hearing loss began (10 years after the shunt was placed), she underwent a shunt revision in which her valve was changed to a higher-pressure device. After the procedure, she had a significant improvement in her speech discrimination and a mild improvement in her pure tone recognition. These changes were documented with serial audiograms. CONCLUSION Hearing loss after cerebrospinal shunting procedures is not always limited to the immediate postoperative period. It may be a late complication of cerebrospinal fluid diversion. Chronic hearing loss after ventriculoperitoneal shunting may be treatable by changing the valve to a higher-pressure device. The etiology of hearing loss from intracranial hypotension is briefly discussed.

BACKGROUND Familial arteriovenous malformations (AVMs) of the brain are rare. We present two sisters with the same parents who harbored AVMs that were successfully treated. METHODS The elder sister presented with a unilateral migrainous type of headache overlying the right parietal area. The younger one suffered from exercise-induced headaches. Both were neurologically intact. Magnetic resonance imaging scans of the brain and cerebral angiography delineated the lesions. Both sisters underwent endovascular embolization followed by surgical resection. RESULTS Postoperatively, aside from a left inferior quadrantanopsia in the elder sister, both were neurologically intact. CONCLUSIONS We report the rare occurrence of familial AVMs in two siblings and review the literature of 14 reports. No genetic predisposition was found.

Carotid cavernous aneurysms are distinct entities. The anatomy of the cavernous sinus region has been well defined, and most spontaneous aneurysms of the cavernous sinus region carry a benign prognosis. Progressively symptomatic, traumatic, or infectious aneurysms require treatment. This can be accomplished by carotid occlusion, extra cranial to intracranial bypass, or direct surgery.

OBJECTIVE AND IMPORTANCE: We present a patient who experienced a subarachnoid hemorrhage secondary to a dissecting aneurysm of the right posteroinferior cerebellar artery (PICA). The use of an encircling clip in treating the aneurysm while preserving supply to brain stem perforators originating near the dissecting segment and the distal PICA territory was key in the operative management. CLINICAL PRESENTATION: A 48-year-old patient with a history of hypertension presented with subarachnoid hemorrhage confirmed by computed tomography of the brain. Successive cerebral angiography revealed a dynamic change in the configuration of the dissection, with expansion of the associated focal ectasia. OPERATIVE MANAGEMENT: At surgery, three brain stem perforators adjacent to the aneurysm were visualized. The dissecting segment was reconstructed with an encircling Sundt clip and muslin wrap, which preserved the flow through the PICA and brain stem perforators. CONCLUSION: A patient suffering from a dissecting PICA aneurysm and subarachnoid hemorrhage was successfully treated with direct surgical reconstruction of the parent artery, sparing the perforators to the medulla.

We present the case of a traumatic posterior cerebral artery aneurysm from a self-inflicted pneumatic nail-gun missile injury through the roof of the mouth. The patient presented to us in a coma with subarachanoid and intraventricular hemorrhage. Cerebral angiography revealed an aneurysm of the left posterior cerebral artery with no distal filling. The patient died 6 days after admission. At autopsy, a pseudoaneurysm of the posterior cerebral artery was seen. This aneurysm resulted from direct disruption of the arterial wall by the intracranial nail.

The majority of intracranial arteriovenous malformations (AVMs) do not require acute surgical intervention. Some patients, however, require emergent surgical treatment because of a profound neurological deterioration from a mass effect. We report 10 patients who underwent emergency AVM surgery after experiencing neurological deterioration from an intracranial hemorrhage. Two patients bled spontaneously, whereas eight had an intracranial hemorrhage secondary to an embolization procedure. When the patients demonstrated neurological deterioration, they were intubated, hyperventilated, and underwent osmotic diuresis. Barbiturate anesthesia was initiated, and surgery was performed within 30 minutes in most cases. The hematomas were evacuated, and an attempt was made to excise the AVMs at the same time. Postoperatively, intracranial pressure was monitored, and barbiturate coma was maintained until the intracranial pressure returned to normal. Cerebral perfusion pressure was maintained above 55 mm Hg. The operation was confined to evacuating the hematoma in two patients with inoperable AVMs. The other eight patients underwent concomitant total AVM resection. Because of the severity of neurological deterioration, one patient who bled spontaneously underwent surgery based only on a computed tomographic scan of the brain. Nine patients made a good-to-excellent recovery. One patient with a large motor-strip AVM remained hemiplegic. We conclude that in patients presenting with profound neurological deterioration after a spontaneous intracranial hemorrhage or one associated with an embolization procedure, prompt hematoma evacuation with simultaneous AVM excision as well as perioperative intracranial pressure control with mannitol and barbiturates can yield a good-to-excellent outcome.

✓ In 15% of patients with spontaneous subarachnoid hemorrhage (SAH), the source of bleeding cannot be determined despite repeated cerebral angiography. However, some patients diagnosed as having “SAH of unknown cause” actually harbor undetected aneurysms. The authors report six patients with SAH who, despite multiple negative cerebral angiograms, underwent exploratory surgery due to a high clinical and radiographic suspicion for the presence of an aneurysm. Brain computerized tomography (CT) scans revealed blood located mainly in the basal frontal interhemispheric fissure in four patients, in the sylvian fissure in one patient, and in the interpeduncular cistern in one patient. The patients were evaluated as Hunt and Hess Grades I to III, and had undergone at least two high-quality cerebral angiograms that did not reveal an aneurysm. Vasospasm was visualized in two patients. Three patients rebled while in the hospital. Exploratory surgery was performed at an average of 12 days post-SAH. Five aneurysms were discovered at surgery and were successfully clipped. All four patients with interhemispheric blood were found to have an anterior communicating artery (ACoA) aneurysm. The patient with blood in the sylvian fissure was found to have a middle cerebral artery aneurysm. These aneurysms were partially thrombosed. No aneurysm was detected in the patient with interpeduncular SAH, despite extensive basilar artery exploration. Five patients had an excellent outcome and one patient developed diabetes insipidus. These results show that exploratory aneurysm surgery is warranted, despite repeated negative cerebral angiograms, if the patient manifests the classical signs of SAH with CT scans localizing blood to a specific cerebral blood vessel (particularly the ACoA) and if a second SAH is documented at the same site.

✓ Endovascular therapy of cerebral arteriovenous malformations (AVM's) is an accepted adjunct to surgical therapy. However, the literature has not characterized the benefits or the liabilities of preoperative embolization. This series compares two groups of patients who underwent surgical resection of a cerebral AVM; one group (20 patients) received preoperative transfemoral selective embolization with N-butyl cyanoacrylate (NBCA) and the other group (13 patients) did not. In the group with preoperative embolization, the AVM's were larger (3.9 vs. 2.3 cm) and of a higher Spetzler-Martin grade (3.2 vs. 2.5) as compared to the nonembolized group. The NBCA embolization facilitated surgical resection. Arteries supplying the vascular malformation were readily distinguished from those supplying the normal brain parenchyma. Embolized vessels were compressible and easily cut with microscissors. No bleeding occurred from transected vessels. Operative time and intraoperative blood loss for the two groups were not statistically different, despite the significant differences in lesion size and grade. Endovascular complications included immediate and delayed hemorrhage (15%) and transient ischemia (5%); there were no embolization-related deaths. Postoperative complications for both groups included hemorrhage (15%), residual AVM (6%), and cerebrospinal fluid leak (3%); the mortality rate was 3%. There was no statistically significant difference in surgical complications between the embolized and nonembolized groups. Most patients (91%) in both groups had an excellent or good late neurological outcome, with no significant difference between the groups. This study concludes that preoperative NBCA embolization of AVM's makes lesions of larger size and higher grade the surgical equivalent of lesions of smaller size and lower grade by reducing operative time and intraoperative blood loss, with no statistically significant difference in surgical complications or long-term neurological outcome.

✓ A patient harboring a cerebral arteriovenous malformation (AVM) underwent angiography in an attempt to embolize the AVM. During catheterization (and prior to embolization) he became hemiplegic and aphasia Angiography revealed a complete middle cerebral artery (MCA) occlusion by an embolus. The patient was treated with recombinant tissue plasminogen activator (t-PA), a thrombolytic agent. Restoration of MCA flow was achieved, and the patient recovered. Immediately after MCA embolus, t-PA infusion may lead to thrombolysis and neurological recovery. The decision-making process as well as the risks associated with the use of t-PA are discussed.

OBJECTIVE To describe a frameless stereotactic technique used to resect cerebral arteriovenous malformations (AVMs) and to determine whether frameless stereotaxy during AVM resection could decrease operative times, minimize intraoperative blood losses, reduce postoperative complications, and improve surgical outcomes. METHODS Data for 44 consecutive patients with surgically resected cerebral AVMs were retrospectively reviewed. The first 22 patients underwent resection without stereotaxy (Group 1), whereas the next 22 patients underwent resection with the assistance of a frameless stereotaxy system (Group 2). RESULTS The patient characteristics, AVM morphological features, and percentages of preoperatively embolized cases were statistically similar for the two treatment groups. The mean operative time for Group 1 was 497 minutes, compared with 290 minutes for Group 2 (P = 0.0005). The estimated blood loss for Group 1 was 657 ml, compared with 311 ml for Group 2 (P = 0.0008). Complication rates, residual AVM incidences, and clinical outcomes were similar for the two groups. CONCLUSION Frameless stereotaxy allows surgeons to 1) plan the optimal trajectory to an AVM, 2) minimize the skin incision and craniotomy sizes, and 3) confirm the AVM margins and identify deep vascular components during resection. These benefits of stereotaxy were most apparent for small, deep AVMs that were not visible on the surface of the brain. Frameless stereotaxy reduces the operative time and blood loss during AVM resection.

Background: Epithelioid hemangioendothelioma (EHE) is a rare sarcoma of vascular origin, which is clinically and histologically intermediate between benign hemangioma and angiosarcoma. It is most commonly found in the liver, lung, and bone, however, 46 intracranial cases have been reported in the literature, of which this is the fifth reported suprasellar tumor. Case Description: A 45-year-old woman developed progressive lethargy, somnolence, and memory decline over the course of 6 months. On computed tomography (CT), she was found to have a large hypothalamic mass and underwent subtotal resection via a bifrontal craniotomy. Conclusions: While primary intracranial EHE is an uncommon presentation of a rare tumor, the suprasellar region does not seem to be an unusual location when it does occur. Prognosis is generally good, and may be better for primary intracranial disease than that for EHE originating elsewhere. Surgery is the first line of therapy, with variable benefit from adjuvant chemotherapy or radiation when total resection is not possible. Chemotherapeutic approaches in current use are directed at preventing endothelial proliferation.

Background and Purpose— Genetic factors for brain arteriovenous malformation are unexplored because of the low incidence of familial cases, albeit local and familial clustering. We used a combination of a linkage study and an association study to explore the genetic background. Methods— A genome-wide linkage analysis was performed in 12 patients from 6 unrelated families using the GENEHUNTER program. A genome-wide association analysis of 26 cases and 30 controls was performed using a GeneChip 10K mapping array. Significance levels for linkage and single single-nucleotide polymorphism association analyses were set at P P Results— The linkage analysis revealed 7 candidate regions, with the highest logarithm of odds score of 1.88 ( P =0.002) at chromosome 6q25. A significant association was observed for 4 single-nucleotide polymorphisms and 2 haplotypes, but none of them overlapped with candidate linkage regions. Genotyping of the twins showed no genetic heterogeneity. Conclusions— The present study failed to identify genetic factors for arteriovenous malformation although the low statistical power may have resulted in such evidence being missed.

Background: Open abdominal aortic aneurysm repair has become increasingly less common in the endovascular era. This approach to open aortic aneurysm repair illustrates the usefulness of mobilizing the right colon cranially to aid in exposing the aorta. This approach is particularly helpful in cases of prior left hemicolectomy or in cases that require suprarenal clamping. Technical Description: After a midline laparotomy incision is performed, the cecum and right colon are mobilized along an avascular plane to allow for reflection of the right colon cranially. The duodenum is mobilized to further expose the aorta. The cecum, right colon, and small bowel is packed towards the right upper quadrant to allow for optimal exposure of the aorta. Aortic aneurysm repair is performed in standard fashion. The cecum is returned to the right lower quadrant and the small bowel is returned to its native location and covered with omentum prior to abdominal wall closure.

OBJECTIVE: The purposes of this article are to summarize recent developments and concerns in endovascular aneurysm therapy leading to the adjunctive use of endoluminal devices, to review the published literature on stent-supported coil embolization of cerebral aneurysms, and to describe our experience with this technique in a limited subgroup of problematic complex aneurysms over a medium-term follow-up period. METHODS: Between January 2003 and June 2004, 28 individuals among 157 patients with cerebral aneurysms we evaluated were identified as harboring aneurysms with exceptionally broad necks. Out of these 28 patients, 16 were treated with a combination of stents and detachable coils, preserving the parent artery. Recorded data included patient demographics, the clinical presentation, aneurysm location and characteristics, procedural details, and clinical and angiographic outcome. RESULTS: Over an 18-month period, 16 patients with large cerebral aneurysms additionally characterized by neck sizes between 7 and 14 mm were treated, using combined coil embolization of the aneurysm with stent reconstruction of the aneurysm neck. Thirteen out of the 16 aneurysms were occluded at angiographic reevaluation between 11 and 24 months (mean angiographic follow-up, 17.5 mo). There were no treatment-related deaths or clinically evident neurological complications. Thirteen patients experienced excellent clinical outcomes, with good outcomes in two patients and a poor visual outcome in one patient (mean clinical follow-up, 29 mo). A single technical complication occurred, involving transient nonocclusive stent-associated thrombus, which was treated uneventfully with abciximab. CONCLUSION: Stent-supported coil embolization of large, complex-neck cerebral aneurysms seems to provide superior medium-term anatomic reconstruction of the parent artery compared with historic series of aneurysms treated exclusively with endosaccular coils. In the near future, increasingly sophisticated endoluminal devices offering higher coverage of the neck defect will likely enable more definitive endovascular treatment of complex cerebral aneurysms and further expand our ability to manipulate the vascular biology of the parent artery.

Background The purpose of this study was to report our operative technique and lessons learned using saphenous vein conduits to revascularize the rostral basilar circulation (ie, bypass to the posterior cerebral or superior cerebellar arteries). We also review the evolution of this technique for the treatment of vertebrobasilar insufficiency (VBI) and complex posterior fossa aneurysms. Methods Data were collected retrospectively for 8 consecutive patients undergoing rostral basilar circulation saphenous vein bypass grafts at our institution between 1989 and 2004 for the treatment of VBI or in conjunction with Hunterian ligation of complex posterior circulation aneurysms. The indications for treatment, pre- and postoperative neurologic status, angiographic results, operative complications, and long-term clinical outcomes were analyzed for each patient. Results With clinical and angiographic follow-up ranging from 3 months to 15 years, 7 of 8 bypasses remained patent, 3 of 3 aneurysms remained obliterated, and 4 of 5 patients with VBI experienced resolution of their preoperative symptoms. There were no surgery-related deaths, but 2 patients did experience major neurologic morbidity. The outcomes for the 217 total patients reported in the literature were as follows: 135 excellent (62%), 26 good (12%), 30 poor (14%), and 26 dead (12%). Conclusions Despite the risk of serious neurologic complications with this procedure, when one considers the natural history of untreated patients, saphenous vein revascularization of the rostral basilar circulation remains an acceptable option. Although surgical technique has varied, patient selection criteria, graft patency, and patient outcomes have been relatively constant over the past 25 years.

✓ The authors present the case of a patient who suffered from progressive cranial nerve dysfunction, radiographically documented brainstem compression, and peduncular hallucinosis after undergoing endosaccular coil placement in a giant basilar apex aneurysm. Symptom resolution was achieved following clip ligation of the basilar artery. The pathogenesis of aneurysm mass effect due to coil placement is discussed and the pertinent literature is reviewed.

Objective To review the natural history and determine the rates of intra- and extralesional hemorrhaging of brainstem cavernous malformations (cavernomas) monitored by one neuro-ophthalmology service. Methods A record review of all patients with brainstem cavernomas who were evaluated by a neuroophthalmology service between 1987 and 1999 was performed. We recorded the clinical symptoms and Rankin disability grade at presentation, during the worst clinical episode, and at the last follow-up examination. Magnetic resonance imaging scans were reviewed for evidence of intralesional hemorrhage (a bleeding episode), edema, or venous anomalies, and the cavernoma size was assessed. Results Thirty-seven patients (age range, 6-73 yr; mean age at presentation, 37.5 yr) underwent a mean of 4.9 years of follow-up monitoring. At presentation, there were 27 bleeding events and 8 nonhemorrhagic events; 2 patients did not exhibit symptoms. Patients who were at least 35 years of age exhibited a lower risk of bleeding episodes (odds ratio, 0.15; 95% confidence interval, 0.1-0.4). Cavernomas of at least 10 mm were associated with a higher risk of bleeding episodes (odds ratio, 3.48; 95% confidence interval, 1.3-9.4). Thirty-nine bleeding episodes occurred in 31 patients, yielding a bleeding rate of 2.46%/yr. There were eight rebleeding episodes, yielding a rebleeding rate of 5.1%/yr. Three patients experienced extralesional bleeding episodes; all of these patients experienced rebleeding. Of the 39 follow-up magnetic resonance imaging scans, the cavernoma size was unchanged in 66.7%, smaller in 18%, and larger in 15%. At the last follow-up examination, the mean Rankin grade was 1.0 for all patients, 0.6 for the 25 nonsurgically treated patients, and 1.4 for the 12 surgically treated patients. Conclusion Rebleeding is not more common among patients who first present with bleeding, and it often has little effect on the neurological status of patients. Significant morbidity attributable to a brainstem cavernoma occurred in 8% of patients during follow-up monitoring of medium duration.

Intramedullary spinal cord abscesses are relatively uncommon. We report the first case of an intramedullary spinal cord abscess in a preexisting spinal cord ependymoma. The clinical features and pathogenesis are discussed. Salient features of the management of intramedullary spinal cord abscesses are outlined.

Background Pituitary adenoma may present with neuro-ophthalmic manifestations and, typically, rapid tumor expansion is the result of apoplexy. Herein, we present the first case of an isolated sixth cranial nerve palsy as initial feature of a rapidly expanding ACTH positive silent tumor without apoplexy. Case Presentation A 44 year old female with a history of sarcoidosis presented with an isolated sixth cranial nerve palsy as the initial clinical feature of a rapidly expanding ACTH positive silent pituitary adenoma. The patient underwent emergent transsphenoidal hypophysectomy for this rapidly progressive tumor and subsequently regained complete vision and ocular motility. Despite tumor extension into the cavernous sinus, the other cranial nerves were spared during the initial presentation. Conclusions This case illustrates the need to consider a rapidly growing pituitary tumor as a possibility when presented with a rapidly progressive ophthalmoplegia.

✓ Recently, the benign nature of aneurysms of the cavernous carotid artery has been questioned. In a review of cases evaluated from 1980 to 1990 with this developmental aneurysm, the authors found 70 patients with 79 cavernous carotid artery aneurysms. As expected, the great majority (59 patients) had ophthalmoplegia as the initial problem. Retro-orbital pain (three cases) and a carotid-cavernous fistula (five cases) were infrequently the sole manifestation. Mirror-image asymptomatic aneurysms were found in nine patients and asymptomatic cavernous aneurysms were found in three additional patients. Thirty-four patients not surgically treated were followed for a mean of 2.8 years, and 36 surgical patients were followed for a mean of 4.1 years prior to treatment. Of the 79 aneurysms, one (1.3%) ruptured into the subarachnoid space during this period. Other than optic neuropathy or cranial neuropathy, no patient had a permanent neurological deficit; the 12 asymptomatic aneurysms remained asymptomatic. It is concluded that an aneurysm of the cavernous carotid artery is rarely associated with life-threatening complications, and treatment should be considered principally for patients with intolerable pain or problems related to vision.

Objective and importance Locked-in syndrome is a state of preserved consciousness in the setting of quadriplegia, anarthria, and usually also includes lateral gaze palsy. It is most commonly associated with upper brainstem infarction variably sparing the third cranial nerve nucleus. There are likely many etiologies that contribute to this clinical syndrome. These are incompletely understood, and the syndrome remains a rare but devastating complication that can occur after neurosurgical and neurovascular interventions. Advanced magnetic resonance imaging techniques such as perfusion and diffusion tensor imaging may help to elucidate the mechanism behind locked-in syndrome. To the authors' knowledge, there are no reports in the literature of perfusion and diffusion tensor findings in patients with this syndrome. A postprocedural case of locked-in syndrome is described with abnormalities on perfusion and diffusion tensor imaging in the absence of any changes in conventional magnetic resonance imaging. Clinical presentation A 57-year-old man who presented with acute onset headache, ataxia, and other nonspecific symptoms was found on imaging to have a giant fusiform basilar artery aneurysm. Intervention A saphenous vein graft bypass between the proximal right external carotid artery and P2 segment of the right posterior cerebral artery followed immediately by endovascular embolization of the aneurysm sac and distal left vertebral artery was performed. Conclusion Postprocedural angiography demonstrated patency of the bypass graft, and diffusion weighted imaging showed no evidence for acute brainstem infarction. Nevertheless, despite technically successful procedures and the absence of abnormalities on conventional magnetic resonance imaging, the patient developed quadriplegia and anarthria and remained in a locked-in state until he expired. Abnormalities were, however, seen on both perfusion and diffusion tensor imaging, where hypoperfusion, increased mean diffusivity, and decreased fractional anisotropy were observed in the ventral brainstem. The findings suggested a disruption of pontine white matter tracts. Advanced imaging techniques may allow us to image important microstructural changes that were previously not discernable and assist in the evaluation of patients with complex neurological sequelae such as locked-in syndrome.

OBJECTIVE:Meningiomas, although histologically benign, pose a particular challenge to the neurosurgeon because of their extensive and exuberant vascularity. They often bleed extensively during resection until separated from their blood supply. There are a wide variety of hemostatic agents available to the neurosur-geon. Most of these means of hemostasis involve some sort of chemical, electrical, or compressive action. Although anecdotally known to be useful, the use of hydrogen peroxide as an intracranial hemostatic agent in meningioma surgery has not been formally reported. We report a technique of meningioma resection that uses intratumoral hydrogen peroxide injection, reducing the potential for blood loss and shortening resection times.METHODS:Seventy-five patients underwent resection of a meningioma using the direct intratumoral H2O2 injection technique. The locations of these meningiomas included convexity and cranial-based lesions. None of the patients underwent preoperative endovascular embolization.RESULTS:The use of this technique greatly facilitated the removal of these tumors. No evidence of air embolism occurred during Doppler surveillance and no other significant side effects attributable to H2O2 application were observed. @@CONCLUSION:@@ We demonstrate a previously unreported technique of meningi-oma resection that uses direct intratumoral hydrogen peroxide injection, potentially reducing blood loss, shortening resection times, and obviating the need for preoperative embolization.

OBJECTIVE: The pretemporal approach has gained popularity for the treatment of basilar apex aneurysms. However, it requires the sacrifice of anterior temporal bridging veins to allow posterior temporal lobe retraction and, for patients with dominant pretemporal venous drainage, has the attendant risk of venous hypertension, hemorrhagic venous infarction, or seizures postoperatively. Alternatively, we have found that splitting the sylvian fissure, resecting the uncus, and applying posterolateral retraction to the medial temporal lobe provides a similar exposure to the basilar apex while preserving the anterior temporal bridging veins. To evaluate the transsylvian, trans-uncal approach to the basilar apex, we report our initial clinical results using this exposure in eight consecutive patients. A morphometric cadaveric analysis comparing this approach with the pretemporal approach was also performed. METHODS: For the clinical study, all hospital charts and imaging studies were retrospectively reviewed for patients undergoing the transsylvian, trans-uncal approach for the treatment of an upper basilar trunk aneurysm between July 2000 and July 2002. In the anatomic study, six formalin-fixed cadaver specimens were used. Two sequential exposures of the basilar apex were performed on each specimen side. First, the pretemporal exposure was performed with anteroposterior temporal lobe retraction. Next, after the temporal lobe had been allowed to return to normal anatomic position, the retractor was repositioned on the medial aspect of the temporal lobe superficial to the uncus, and a 10 × 10 × 15-mm volume of uncus was removed. Morphometric measurements were performed for each exposure. RESULTS: Four basilar bifurcation and four superior cerebellar segment aneurysms in eight consecutive patients were successfully clip-ligated by use of the transsylvian, trans-uncal approach. All patients had temporal bridging veins that were preserved, as documented by angiography and operative reports. No patient developed a venous infarction or new postoperative seizures, with a mean follow-up of 9.75 months (range, 0.5–28 mo). The cadaveric analysis revealed that in addition to providing a similar exposure of the upper basilar complex, the transsylvian, trans-uncal approach provided additional exposure of the ipsilateral posterior cerebral and superior cerebellar arteries compared with the pretemporal approach. CONCLUSION: When approaching the basilar bifurcation, the transsylvian, trans-uncal approach provides superior exposure of the ipsilateral superior cerebellar and posterior cerebral arteries compared with the pretemporal approach, while preserving the anterior temporal bridging veins. This approach is most valuable in patients with dominant temporal venous drainage or when additional exposure of the ipsilateral posterior cerebral or superior cerebellar arteries is required.

✓ The objective of this study was to evaluate the effects of mannitol, given over different time periods, on regional cerebral blood flow (rCBF) in patients with intracranial aneurysms. Seven patients with unruptured aneurysms (Group I) and 16 patients with Grade I and II subarachnoid hemorrhage (SAH) (Group II) received 1.5 gm/kg/8 hrs of 20% mannitol intravenously over a 24-hour period. Seven other patients with unruptured aneurysms (Group III) received 1.5 gm/kg of mannitol over 8 hours only. The last seven patients with unruptured aneurysms (Group IV) received the same dose, but as an intravenous bolus. Over a period of 24 hours, the patients underwent serial measurements of rCBF, intracranial pressure (ICP), mean blood pressure (MBP), cardiac output, and cerebral metabolic rate of oxygen consumption (CMRO2). Mannitol, when given as a continuous intravenous infusion, increased rCBF significantly without increasing MBP or decreasing ICP. This increase was more pronounced in SAH patients. The effects of mannitol lasted for 18 hours when given over an 8-hour period only; however, when it was given as a bolus, the increase in rCBF lasted for 24 hours, cardiac output tended to increase, and the effect on CMRO2 was variable.

SUMMARY: Does the world need another ICA classification scheme? We believe so. The purpose of proposed angiography-driven classification is to optimize description of the carotid artery from the endovascular perspective. A review of existing, predominantly surgically-driven classifications is performed, and a new scheme, based on the study of NYU aneurysm angiographic and cross-sectional databases is proposed. Seven segments – cervical, petrous, cavernous, paraophthlamic, posterior communicating, choroidal, and terminus – are named. This nomenclature recognizes intrinsic uncertainty in precise angiographic and cross-sectional localization of aneurysms adjacent to the dural rings, regarding all lesions distal to the cavernous segment as potentially intradural. Rather than subdividing various transitional, ophthalmic, and hypophyseal aneurysm subtypes, as necessitated by their varied surgical approaches and risks, the proposed classification emphasizes their common endovascular treatment features, while recognizing that many complex, trans-segmental, and fusiform aneurysms not readily classifiable into presently available, saccular aneurysm-driven schemes, are being increasingly addressed by endovascular means. We believe this classification may find utility in standardizing nomenclature for outcome tracking, treatment trials and physician communication.