Historical aspects of microsurgical treatment of brain aneurysms

BackgroundInitial technical constraints on the treatment of aneurysms in small parent vessels using flow diverters included challenges in navigating the delivery system and catheter size compatibility, as well as unavailability...

The Silk Vista Baby (SVB, BALT) is a first-in-class flow-diverter device delivered using a 0.017" microcatheter, designed for the treatment of intracranial aneurysms, including those in small diameter vessels. This study reports a systematic literature review (SLR) to evaluate the safety and efficacy of using SVB to treat intracranial aneurysms in vessels less than 3.5 mm in diameter. We performed a PRISMA-compliant SLR to evaluate the outcomes of SVB in the treatment of aneurysms in small intracranial vessels. Primary outcomes were occlusion status and major stroke, and secondary outcomes included all-cause mortality, procedure-related neurologic death, and post-operative aneurysm rupture. Data were expressed as descriptive statistics only. A total of four studies, including 163 patients with 173 intracranial aneurysms, were included. The most common aneurysm locations were the anterior cerebral artery (24.9% [43/173]), the middle cerebral artery (24.3% [42/173]), and the anterior communicating artery (23.1% [40/173]). Parent artery diameter ranged from 0.9 mm to 3.6 mm, and 29% were acutely or previously ruptured aneurysms. Overall, complete or near-complete occlusion was 72.1% on early-term follow-up. Mortality rate among the studies was 2.5%, with 3 instances adjudicated as neurologic deaths (1.8%). Major stroke was noted in 1.2% of cases, and branch occlusion or stent thrombus formation in 5.5%. Our review suggests that SVB is a safe and effective treatment for intracranial aneurysms in small vessels. Further prospective and comparative studies with patient outcome data specific to aneurysm location are needed to confirm the safety and efficacy of SVB.

Interventional neuroradiology.

The frequency of multiple intracranial aneurysms seen in patients with or without subarachnoid hemorrhage is high. The advancement of the endovascular technique and devices has ensured that endovascular treatment of intracranial aneurysms is the first choice in most cases, especially in unruptured ones. Different combinations of treatment modalities and techniques can be used in the management of multiple aneurysms. But in selected patients without subarachnoid hemorrhage, treatment of all aneurysms in one or more sessions with endovascular techniques is less traumatic than that with surgery. In the literature, the maximum number of aneurysms in one patient treated endovascularly and/or surgically is seven. In this case report, we present, with a review of the literature, a patient with eight intracranial aneurysms, all of which were treated in two sessions with various endovascular techniques. A 40-year-old female patient was admitted due to headache. Angiography showed eight aneurysms in the posterior circulation and, bilaterally, in the anterior circulation. All aneurysms were treated endovascularly in two sessions. In the treatment of the aneurysms, different endovascular techniques were used including flow diverters stents, stent-assisted coiling, Y-stent-assisted coiling, and coiling alone.

The evolution of endovascular treatment of cerebral aneurysms has logically developed in the direction from non-constructive methods (treatment of aneurysms using detachable balloons, using liquid embolizing agents, occlusion of aneurysms with detachable coils, occlusion of aneurysms with balloon-assisted coils, implantation of various types of intradaccular devises) to reconstruction of the artery segment carrying the aneurysm (occlusion of aneurysms with stent-assisted coils and the use of flow-diverters). The effectiveness of these methods, including in the treatment of patients in the acute period of aneurysm rupture, in the immediate postoperative period has been proven by a variety of randomized studies, at the same time, in the long-term period, there are cases of aneurysm recurrence, including those accompanied by its rupture and the need for repeated surgical treatment. It should be noted that the development and modernization of various devices for the treatment of cerebral aneurysms is aimed at reducing the risk of operational complications and achieving greater radicality not only in the near, but also in the long-term postoperative period. The purpose of this review is to describe the stages of development of endovascular treatment of cerebral aneurysms. In this work, we describe the most well-known non-constructive methods of treatment.

Anterior choroidal artery aneurysms are rare intracranial aneurysms, accounting for 2%-5% of the incidence of all intracranial aneurysms. Because the anterior choroidal artery is a small artery with lacks of effective collateral compensation, it is easy to cause anterior choroidal artery injury and ischemia to lead to anterior choroidal artery syndrome in the treatment of aneurysms. At present, scholars have published a large number of literatures on the surgical and endovascular treatment of anterior choroidal artery aneurysm, but there is still a lack of relevant review articles. This study summarizes the treatment of prechoroidal artery aneurysm related ischemic risk and treatment strategies as follows. Key words: Anterior choroidal artery aneurysm; Anterior choroidal artery syndrome; Endovascular treatment; Postoperative ischemia

President's Opening Remarks.- Fedor Krause Memorial Lecture.- Neurosurgical Standards.- Neurosurgical Standards and Quality Assurance.- The Concept of Neurosurgical Standards from the Clinician's Perspective.- Medical Treatment Standards from a Legal Perspective.- Cerebral Aneurysms.- Endovascular Treatment of Berry Aneurysms by Endosaccular Occlusion.- Strategies of Endovascular Treatment of Large and Giant Intracranial Aneurysms.- Endovascular Treatment of Basilar Bifurcation Aneurysms.- Embolization of Large Aneurysms with Detachable Balloons.- Endovascular Treatment of Internal Carotid Artery Aneurysms.- Possibilities and Limitations of Endovascular Techniques for the Treatment of Craniocerebral Aneurysms.- Technical Possibilities and Aids in Treating Aneurysms in Open Surgery.- Surgical Procedure in Multiple Cerebral Aneurysms.- Circulatory Arrest and Hypothermia in the Treatment of Cerebral Aneurysms: Preliminary Results.- Principles of Aneurysm Surgery in the Acute Stage of Subarachnoid Hemorrhage.- Prognosis of Aneurysmal Subarachnoid Hemorrhage: Prospective Study on 543 Patients.- Early Versus Delayed Aneurysm Surgery in Subarachnoid Hemorrhage in Clinical Grade Hunt-Hess III.- Poor-Grade Patients with Aneurysmal Subarachnoid Hemorrhage: Early or Late Operation?.- Timing and Grading: Problems in Poor-Grade Subarachnoid Hemorrhage.- Early Operation in the Elderly?.- Management Results of a Series of Predominantly Delayed Operations and Ruptured Aneurysms.- Analysis of Relevant Intervals Between Subarachnoid Hemorrhage and Surgery on Patients with Aneurysm and Its Influence on the Decision for Early or Delayed Surgery.- Significance of the History for the Planning of Therapy After Subarachnoid Hemorrhage.- Microsurgical Strategy and Surgical Results in Carotid Ophthalmic Artery Aneurysms.- Surgery in Cases of Subarachnoid Hemorrhage Without Definite Angiographic Evidence of Vascular Malformation.- Differential Diagnostic Problems and Treatment of Thrombosed Giant Intracranial Aneurysms.- Cerebral Artery Aneurysm in Childhood: Surgical Indications and Results.- Multiple Intracranial Aneurysms: Considerations in Planning Surgical Management.- Psychological Stress During Operations of Aneurysms: A Factor in the Surgical Treatment of Aneurysms. Cardiac Output and Blood Pressure of the Surgeon.- Multimodal Monitoring of Evoked Potentials in Subarachnoid Hemorrhage Following a Ruptured Aneurysm.- Necessity of Control Angiography After Aneurysm Surgery.- Magnetic Resonance Angiography of Cerebral Artery Aneurysms: Present Capabilities and Limitations.- Differential Disturbances of Memory and Mood Following Striatum and Basal Forebrain Lesions in Patients with Ruptures of the Anterior Communicating Artery.- Treatment of Cerebral Vasospasm with Hypervolemia and Hypertension.- Value of Transcranial Doppler Sonography in Patients Treated with Nimodipine.- Correlation Between Cerebral Blood Flow Velocity in Basal Cerebral Arteries and Nimodipine Concentration in Serum and Plasma After Acute Subarachnoid Hemorrhage.- Laser Irradiation of Experimental Carotid Aneurysms: Long-term Results and Histological Alterations.- Effects of Intrathecal Thrombolysis on CSF Absorption After Experimental Subarachnoid Hemorrhage.- Malignant Gliomas.- The Neurosurgical Treatment of Malignant Gliomas.- Stereotactic Interstitial Brachycurietherapy (Iridium-192 and Iodine-125) in Nonresectable Low-Grade Gliomas.- Perspectives of Glioma Treatment with Boron Neutron Capture Therapy in Europe.- Clinical Investigations in Boron Neutron Capture Therapy (BNCT): Pharmacokinetic, Biodistribution, and Toxicity of Na2B12H11SH (BSH) in Patients with Malignant Glioma.- Laser-Induced Interstitial Thermotherapy of Malignant Gliomas.- Interstitial Laser-Assisted Thermal Therapy of Central Brain Tumors: Preliminary Report.- Transforming Growth Factors-? in Malignant Glioma: Preliminary Studies on Inhibition by Antisense Oligodeoxynucleotides.- Local Adjuvant Adoptive Immunotherapy of Patients with Malignant Gliomas.- Intratumoral Administration of Interferon-? in Malignant Gliomas.- A Preliminary Study of Superselective Intra-Arterial Cisplatin Infusion in the Treatment of Recurrent Malignant Gliomas.- MTT Assay for In Vitro Chemosensitivity Testing of Malignant Intracranial Tumors.- Radical Resection of Midline Gliomas in Children.- Glioma Surgery Within a General Concept: Ultrasonic Aspiration, Laser Coagulation, Radiotherapy, Relapse Operation, Hyperthermia.- Local Administration of Chemo- and Radiopharmaceuticals.- Combined Radiotherapy of High-Grade Gliomas with Stereotactic Implanted Iodine-125 Seeds and Fractionated Low-Dose Rate Beam Irradiation: Preliminary Results.- Malignant Glioma of the Brain: Not in Every Case a Poor Prognosis?.- Microsurgery of Malignant Gliomas of the Temporal Lobes: Cognitive Deficits Depend on the Extent of Lost Tissue.- Multiple Primary and Multiple Recurrent Gliomas.- Relationship Between the Recurrence of Intracranial Ependymomas and the Grade of Malignancy.- Prognostic and Biological Significance of Gross Residual Tumor Following Extirpation of High-Grade Gliomas: Clinical Study Based on Early Postoperative MR Imaging.- Malignancy-Dependent Formation of Cysteinyl-Leukotrienes in Human Brain Tumor Tissues and Its Detection in Urine.- Immunohistochemical Expression of Epidermal Growth Factor Receptor in Human Gliomas.- Winning Poster and Lecture Presentations.- Pituitary Microcirculation Measured by Laser Doppler Flowmetry: Physiological and Clinical Aspects.- Can Motor Evoked Potentials Contribute to the Indication for Surgery in Cervical Spondylotic Disease?.- Is the Hunt and Hess Scale Outdated?.- Monocyte Killing of Malignant Brain Tumor Cells.- Temporary Middle Cerebral Artery Clipping: Pathophysiological Investigation on the Effect of Mannitol and Nimodipine: A Model for Aneurysm Surgery.- Experimental Peripheral Nerve Regeneration: Interposition of Placenta-Amnion Membrane and Umbilical Cord Versus Autologous Transplantation.- Growth Characteristics and Proliferation Parameters of Invasive Pituitary Adenomas.- Intraoperative Antibiotic Prophylaxis in Neurosurgery: A Prospective Randomized Trial in 840 Patients.

Cerebrovascular neurosurgery is a field where the highs are high and the lows are low. The successful cerebrovascular neurosurgeon gets to save lives and restore neurological function but must also to attend families and patients who are facing stroke and death. Patients generally fall into 2 categories: those who have had hemorrhagic or ischemic strokes, and those who are at risk for stroke but are so far unscathed. Patients in the first group have experienced a catastrophe. The neurosurgeon typically meets the patient and their family in the hospital. Morbidity and mortality within this group is common and can be devastating. The able neurosurgeon must be able to assess the situation and act rapidly to prevent worsening of neurological damage and decide how best to keep the patient from further harm. Those in the second group have often received a diagnosis after medical imaging for an unrelated complaint. While the vascular lesion may be asymptomatic, these patients are fearful and anxious about the possibility of experiencing a stroke. For these patients, neurosurgeons must be able to summarize the available evidence, provide comfort, and recommend the safest treatment option. Sometimes the safest course is not surgery, but instead, reassurance and medical management. Within the following 6 chapters, the authors lay out practical information all physicians should be familiar with. These chapters cover some of the more common diagnoses that we confront and should help to familiarize students with how to analyze, understand, and treat these problems. This is an exciting field and the authors share a passion for doing everything we can to care for our patients and to keep them from harm. It is hoped that these chapters will help to introduce the next generation of physicians to the satisfaction we enjoy when we are able to shepherd patients safely through the risks that they face. Institutional Review Board approval was not necessary for this study. Patient consent for the cases in each chapter was obtained directly from the patients; in instances in which consent could not be obtained, patient information has been anonymized. CHAPTER 1: MICROSURGERY FOR UNRUPTURED INTRACRANIAL ANEURYSMS Case Presentation A female in her mid-fifties without a significant past medical history presented with double vision. Her neurological examination revealed left ptosis, a dilated, nonreactive left pupil, and the inability to adduct and supraduct her left eye. Magnetic resonance imaging (MRI) and computed tomography angiography (CTA) imaging showed a large left internal carotid artery (ICA) aneurysm arising at the origin of the posterior communicating artery (Figure 1). (See discussion at end of chapter.)FIGURE 1.: Axial A, coronal B, and sagittal C CTA revealing a wide-necked, large left posterior communicating artery aneurysm.Questions The relative rupture risk of a posterior communicating artery aneurysm to a cavernous aneurysm is: The same Higher Lower No relationship Of the following aneurysms which has the highest rupture risk (refer to Figure 2): A 12-mm cavernous aneurysm A 12-mm posterior communicating artery aneurysm A 12-mm middle cerebral artery (MCA) bifurcation aneurysm A 12-mm superior hypophyseal artery aneurysm A 12-mm ophthalmic artery aneurysm Which craniotomy is most suitable for clipping a posterior communicating artery bifurcation aneurysm: Far lateral Subtemporal Interhemispheric Pterional Suboccipital A posterior communicating artery aneurysm can cause double vision related to compression of which cranial nerve: 2nd cranial nerve 3rd cranial nerve 5th cranial nerve 7th cranial nerve 8th cranial nerve FIGURE 2.: Location distributions of intracranial aneurysms across the neurovasculature. Abbreviations: Acomm = anterior communicating artery; MCA = middle cerebral artery; Pcomm = posterior communicating artery; PICA = posterior inferior cerebellar artery; SCA = superior cerebellar artery; VB = vertebral/basilar.Epidemiology Approximately 1% of adults have an intracranial aneurysm, most of which are not congenital. Aneurysms are quite rare in children and become more common with age. Perhaps those individuals with aneurysms are born with a weak area in the wall of their vessel and the aneurysm many develop later in life, but it is not fully known. For example, intracranial aneurysms occur in both sexes, but are distinctly more common in females. While most intracranial aneurysms are thought to be sporadic, about 15% run in families. We presume, therefore, there is a genetic basis for this and is inherited, but those genes have not yet been identified. Smoking, hypertension, family history of intracranial aneurysms, polycystic kidney disease, connective tissue diseases, and possibly aortic aneurysms are all correlated with the presence of an intracranial aneurysm; further, these factors also increase the risk of aneurysm rupture. The presence of multiple factors can magnify risk in a synergistic and multiplicative fashion. Patients with familial aneurysms tend to rupture a decade younger than those with sporadic aneurysms. The incidence is higher in families with genetic risk factors, including those with polycystic kidney disease and various connective tissue disorders (ie, Marfan's syndrome, Ehler-Danlos syndrome, etc). In such families where one individual has an aneurysm, the chance of another first-degree family member having an aneurysm may be as high as 30%. It is estimated that 30 000 patients suffer aneurysmal rupture each year. Approximately 50 to 75% of patients who have an aneurysm rupture reach a hospital in time to receive medical care. Of those who attain medical attention, approximately 50% die and another 25% suffer significant complications. Of those patients who receive timely medical care, 25% can have a good outcome. Due to this high mortality rate, it is reasonable to consider treatment in a patient diagnosed with an unruptured intracranial aneurysm. Morphology Ninety percent of intracranial aneurysms are saccular and 10% are fusiform. Most saccular aneurysms occur at bifurcations, but small percentages are sidewall aneurysms. Aneurysms are classified as small (<10 mm), large (10-24 mm), and giant (>24 mm). Infectious aneurysms (also known as mycotic aneurysms) tend to occur on distal intracranial vessels. Saccular aneurysms can have small or wide necks, which can influence treatment difficulty and strategy. As they enlarge, the sac may become filled with thrombosed blood, causing mass effect on surrounding neural tissue. Natural History Several studies have been published that attempted to quantify the risk of rupture of asymptomatic unruptured intracranial aneurysms. It is important that one keep in mind that these studies only address asymptomatic aneurysms. Symptomatic aneurysms almost always necessitate urgent intervention. These studies suffer from relatively short follow-up periods (typically 5 yr or less). These time periods are considered short because for most patients, the question of risk exposure to rupture is one of decades. The most prominent of the natural history studies is the International Study of Unruptured Intracranial Aneurysms (ISUIA) study (Wiebers DO, Whisnant JP, Huston J 3rd, et al. Unruptured intracranial aneurysms: natural history, clinical outcome, and risks of surgical and endovascular treatment. Lancet. 2003 Jul 12;362(9378):103-110). Table 1, which is reproduced from the ISUIA study, shows the relationship between aneurysm location, size, and risk of rupture. The study also showed that larger size, prior history of subarachnoid hemorrhage, and posterior circulation (including posterior communicating artery aneurysms) had a higher risk of rupture. While this suggests low rupture risk for anterior circulation aneurysms <7 mm in diameter, it should be noted that the median size of aneurysm rupture is about 6 mm. Pericallosal and anterior communicating artery aneurysms tend to rupture at smaller sizes than other aneurysms. The median rupture size of this type of an aneurysm is about 3 mm. Certain morphological features have been associated with the risk of rupture, including irregular dome shape and the presence of daughter sacs on the dome. TABLE 1. - Five-Year Annual Cumulative Risk of Aneurysmal Rupture According to Size and Location Within the Intracranial Vasculature (Reproduced from the ISUIA Trial) < 7 mm No Hx of SAH Hx of SAH 7–12 mm 13–24 mm ≥25 mm Cavernous carotid artery 0% 0% 0% 3.0% 6.4% Anterior circulation 0% 1.5% 2.6% 14.5% 40% Posterior circulation 2.5% 3.4% 14.5% 18.4% 50% Hx = history; SAH = subarachnoid hemorrhage. Clinical Presentation Due to the growing utilization of MRI and magnetic resonance angiography (MRA), there is an increasing number of incidentally discovered aneurysms diagnosed when patients are evaluated for unrelated symptoms. Unruptured aneurysms can cause a myriad of symptoms, including cranial neuropathies, seizures, headaches, and cognitive decline due to mass effect. Rarely, an intracranial aneurysm can cause ischemic symptoms due to emboli that result from turbulent flow within an aneurysm. Anatomy and Distribution Figure 2 outlines the location of the most common types of intracranial aneurysms. Eighty percent of aneurysms occur in the anterior circulation and 20% occur in the posterior circulation. Decision Making The decision of whether to treat an aneurysm or not can be complex. Several parameters must be considered, including age, the health of the patient, an assessment of the natural history of the aneurysm, and the technical capabilities of the treating surgeon. One of the most important determinants of the risk of a nonruptured aneurysm is the patient's age and health. Younger age and a longer life expectancy expose the patient to greater cumulative risk than a patient with a more limited life expectancy. Therefore, younger patients have a graver natural history favoring treatment while advanced age accompanied by lower rupture risk favors observation with serial imaging. Despite a growing body of literature on aneurysm behavior and natural history, aneurysm rupture remains unpredictable. Any absolute statements on aneurysm natural history are largely conjecture, and it is important to share this uncertainty with patients. Studies have suggested that outcomes tend to be better at high volume centers. The advent and evolution of endovascular options over the past several decades have increased the neurosurgeon's repertoire of aneurysm treatment modalities. More options may have made decision making more complicated, but it has also allowed a greater number of aneurysms to be treated. Microsurgical and endovascular treatments are associated with inherent benefits and disadvantages. Surgical clipping remains the most definitive way to treat intracranial aneurysms with a proven track record of durability and versatility. Almost all aneurysms can be treated surgically. Endovascular therapies have the advantage of being less invasive and for unruptured aneurysms, patients generally have shorter hospitalizations and recoveries. The disadvantages include risks of the treatment, greater risk of recurrence, and the fact that some aneurysms cannot be treated by current endovascular therapies. Factors that favor clipping as opposed to endovascular treatment include young patient age, wide aneurysm neck, incorporation of outflow branches into the dome, and larger aneurysm size. Surgical Techniques Aneurysm clipping involves exposing the aneurysm along with its inflow and outflow vessels. This technique requires a carefully planned surgical approach that minimizes brain manipulation and takes advantage of the subarachnoid space. With careful planning and positioning, a skilled microsurgeon can navigate atraumatically through the subarachnoid cisterns to first expose the inflow branch to an aneurysm, thus achieving proximal control. Establishing proximal control is an important tenet in aneurysm surgery. The surgeon then carefully exposes outflow vessels, which assures complete control of the circulation related to the aneurysm. This control is important for 3 reasons. First, if the aneurysm leaks during manipulation, flow can be arrested with temporary clips until the aneurysm can be clipped. Flow can be arrested for 20 to 30 min with special anesthetic techniques in most cases, which gives the surgeon time to complete the dissection and clip the aneurysm safely. Second, certain aneurysms with wide necks are best clipped after they are trapped and deflated. Finally, flow arrest may be needed if a bypass is required as part of the aneurysm treatment strategy. During flow arrest, anesthesiologists can give sufficient doses of anesthetic to suppress the electroencephalogram. This is referred to as “burst suppression.” This reduces the metabolic needs of neuronal cells thus increasing the tolerance to temporary flow arrest. Instruments used in aneurysm clipping are shown in Figure 3.FIGURE 3.: A, Various styles of aneurysm clip appliers. B, Different clip styles, both permanent and temporary. C, Clip applier opening a clip.Case Discussion This patient with a cranial nerve III palsy raised concern for an intracranial aneurysm; an awake patient with acute third nerve palsy with pupillary dilation should be assumed to have an aneurysm until proven otherwise. A posterior communicating artery aneurysm is the most likely aneurysm to cause compressive third nerve palsy. Diabetes can also be associated with this deficit and is the most common because of noncompressive third nerve paresis. Diabetes induced third nerve palsy, however, is usually pupil sparring (ie, the pupil is not asymmetrically dilated). In this case, the CTA revealed a wide-necked, large left posterior communicating artery aneurysm (Figure 1). Given the relatively young age of the patient, the mass effect on the third nerve, and the wide neck of the aneurysm, surgical clipping was recommended. At surgery, the wide neck of the aneurysm required trapping and deflation prior to successful clipping. The case is narrated in Video 1. Other clipping cases are discussed in Videos 2 and 3. {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Video 1.","caption":"Trapping and deflation to clip a large Pcomm artery aneurysm. This video can be accessed in the HTML version of the article. Please visit www.operativeneurosurgery-online.com to view this article in HTML and play the video.","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_xpznvs9a"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Video 2.","caption":"Miscrosurgical clipping of paraclinoid aneurysms in 3 patients. This video can be accessed in the HTML version of the article. Please visit www.operativeneurosurgery-online.com to view this article in HTML and play the video.","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_rgt2vrwb"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Video 3.","caption":"Surgical clipping of an unruptured MCA aneurysm. This video can be accessed in the HTML version of the article. Please visit www.operativeneurosurgery-online.com to view this article in HTML and play the video.","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_lfhih4hy"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} Answers to Questions B. The cavernous segment of the ICA is extradural and surrounded by bone and dura. These aneurysms have very low risk of subarachnoid hemorrhage. B. Posterior communicating artery aneurysms have a higher risk of hemorrhage than the other locations listed. D. The pterional or frontotemporal craniotomy is the ideal exposure used for most carotid segment aneurysms. B. The anatomic relationship of the posterior communicating artery to the oculomotor nerve makes this the most common cranial nerve compressed by an enlarging aneurysm at that site. Pearls ✓ Larger aneurysm size, location in posterior circulation (including posterior communicating artery aneurysms), family history of aneurysms, smoking, connective tissue disease, and a history of SAH increase the annual risk of rupture of intracranial aneurysms. ✓ Aneurysm rupture carries significant morbidity and mortality, thus justifying the treatment of many intracranial aneurysms. ✓ Aneurysm clipping is associated with very high rates of durability when compared with endovascular coiling. Patient selection for aneurysm clipping depends on careful analysis of anatomic features, an understanding of the natural history, and an honest appraisal of surgeon expertise. ✓ Endovascular treatment of aneurysms is a less-invasive approach to aneurysm treatment and may be preferable form select patients and select aneurysms. ✓ There are many new techniques arising for diagnosis and treatment of aneurysms, including emerging neurosurgical modalities and technological advancements to care. Care should be individualized and take aneurysm and patient characteristics into account. SUGGESTED READING Murayama Y, Takao H, Ishibashi T, et al. Risk analysis of unruptured intracranial aneurysms: prospective 10-year cohort study. Stroke. 2016;47(2):365-371. Wiebers DO, Whisnant JP, Huston J 3rd, et al. International Study of Unruptured Intracranial Aneurysms Investigators. Unruptured intracranial aneurysms: natural history, clinical outcome, and risks of surgical and endovascular treatment. Lancet. 2003;362(9378):103-110. Juvela S, Porras M, Poussa K. Natural history of unruptured intracranial aneurysms: probability of and risk factors for aneurysm rupture. J Neurosurg. 2000;93(3):379-387. Rhoton AL Jr. Anatomy of saccular aneurysms. Surg Neurol. 1980;14(1):59-66. Samson D, Batjer HH, White J, et al. Intracranial Aneurysm Surgery: Basic Principles and Techniques. New York: Thieme; 2011. Bendok BR, Sattur MG, Welz ME, et al. Patient selection and technical nuances for microsurgical clipping of carotid-ophthalmic aneurysms: 2-dimensional operative video. Oper Neurosurg. 2018;15(2):245. CHAPTER 2: RUPTURED BRAIN ARTERIOVENOUS MALFORMATIONS Case Presentation An otherwise healthy pediatric patient slightly older than the age of 10 presented with sudden onset of severe headache, emesis, and confusion. Initial imaging demonstrated intracerebral hemorrhage (ICH) involving the mesial parietal and occipital lobes with extension into the ventricles (intraventricular hemorrhage [IVH]), and ventriculomegaly (Figure 4). CTA demonstrated an abnormal, periventricular tangle of vessels within the ICH.FIGURE 4.: A, CTA demonstrates an abnormal tangle of blood vessels (white arrow) adjacent to the ICH and IVH (*). B, DSA (lateral view, left vertebral artery). DSA demonstrates a small (1.5 cm), diffuse nidus (arrow), supplied by PCA branches, and arterial feeder has a flow-related aneurysm (arrowhead) proximal to the nidus. Venous drainage is both deep (*) and superficial. The Spetzler–Martin classification is grade II (S1E0V1). C, After embolization, the Onyx cast is demonstrated. D, The portion of the Onyx cast is seen intraoperatively. E, The main draining vein has been cauterized after disconnection of the arterial supply. F, Postoperative DSA demonstrates no residual BAVM.(See discussion at end of chapter.) Questions After stabilizing the patient, initial management would include which of the following: Emergent decompressive craniectomy Evacuation of the ICH Intracranial pressure (ICP) management with external ventricular drain (EVD) placement Diagnostic cerebral angiography After initial management, which of the following would be the next step in Microsurgical of the Diagnostic cerebral angiography would be the grade of this with a 2 diameter, both and deep and II III A brain is a vascular by an abnormal tangle of and known as a nidus. This nidus and vessels that the of blood flow from the arterial to the circulation. can with hemorrhage, seizures, neurological and headache, or as during for other reasons. Patient and anatomic features of help the risk of hemorrhage and risks of treatment. options include microsurgical endovascular embolization, or over management, for unruptured asymptomatic however, treatment with microsurgical or is generally for most with the type of treatment on patient and have a low but are an important cause of The of has been estimated at 50 cases 000 on several the incidence of is case 000 for the incidence is cases 000 year. can patients of age, but most are between 20 and The most common is hemorrhage 50% of by 25% and headache, neurological or which for the The rupture risk of unruptured is to which to 3 to with a history of hemorrhage. have a 2 to risk of hemorrhage year. age, history of hemorrhage, deep brain location, and deep drainage increase the risk of hemorrhage with annual risk of hemorrhage from for patients with of these features to for patients with all The presence of associated aneurysms can risk double the annual risk of hemorrhage. The of size, posterior location, and have not been demonstrated as as prior hemorrhage. is but they have been thought to be a of definitive and as as genetic may to their and and not directly and are by but in of blood between and and the vessels that this tangle of blood vessels are and to rupture. aneurysms can form due to these (ie, proximal and distal flow-related aneurysms), as as within the abnormal (ie, These aneurysms may often be the of hemorrhage. become due to these and and as a result they may develop an or These features may not the risk of hemorrhage, but they are important in treatment planning and as of these will increase pressure and to hemorrhage. In to rupture and the of hemorrhage with brain and increased unruptured the surrounding brain due to and which can to cognitive and and Initial of or SAH are generally diagnosed on computed tomography imaging. CTA is which often demonstrates the and draining it may also associated aneurysms. With the initial special is to IVH or large with of mass brain as as hemorrhage in the posterior because these may treatment with placement or decompressive the patient's examination with these imaging will their management. Patients with are to the neurosurgical care for of their neurological and medical cerebral angiography angiography is to further the DSA will anatomic features that will help management, including the number and location of associated aneurysms and of size and of or of drainage and presence of or ICH from a may or the nidus and flow is typically during of unruptured and can assess the and brain MRI can of prior hemorrhage with imaging to blood and of with increased imaging. with CTA and is also used for planning treatment. are important for the of as as management The most used is the Spetzler–Martin grade The Spetzler–Martin grade is also used The and the are used to risk of treatment from but are less used during the initial management of a TABLE - and grade 2 3 location location Venous drainage only Any deep drainage grade grade yr yr 2 yr 3 history Unruptured of nidus TABLE 3. - of for the Most of Aneurysms Anterior cerebral artery Anterior communicating artery cerebral artery Posterior communicating artery carotid artery TABLE - The and = 2 location History of hemorrhage = = 1. receive to 5 in the Spetzler–Martin on size drainage or and location One is for an aneurysm size 2 for a size 3 to 6 and 3 for a size One is for deep and is for Venous drainage is considered if the into and then to deep drainage through the vein of is anatomic and as internal cerebellar and deep cerebellar This has been into 3 on surgical morbidity and mortality (ie, A, B, and C for and Surgical morbidity and mortality increase with increased such that outcomes occur in of A, of B, and of C patients. The Spetzler–Martin grade was on the observation that age, hemorrhage, and of the nidus also outcomes obtained from age, hemorrhage, and are to the Spetzler–Martin < 20 and yr are 1, and 3 on unruptured carries more surgical risk and has a higher of from than for A diffuse nidus is more likely to have brain within the nidus and is more to than a with a nidus The Spetzler–Martin grade from 2 to and risk of surgical treatment with higher Patients with unruptured are

Aneurysm (AN) treatment appears to differ from country to country and even from centre to centre. Therefore we decided to conduct a survey in order to better understand the "state of the art" in aneurysm treatment in Europe. The primary aim was to understand the roles of clipping and coiling in aneurysm treatment. An interactive form was sent to major European neurosurgical centres. The responses relating to AN location, status (ruptured/unruptured) and treatment modality were divided with regard to the volume of cases and the centre's geographical location. Responses were received from 96 European centres. The main finding was that clipping was used significantly more often in Eastern Europe than in the rest of Europe to treat ruptured ANs of the anterior circulation. Almost all ruptured ANs across all locations are treated actively. The treatment of unruptured aneurysms of the anterior circulation is similar. The median relating to observed unruptured ANs across the Europe was 10 %. Posterior circulation ANs are treated predominantly by coiling, regardless of aneurysm status or geographical location. The average number of coilers versus surgeons per centre was 2.5:3.0 in Western, 1.9:3.6 in Southern, 1.9:4.3 in Eastern and 2.7:3.1 in Northern Europe. The way in which intracranial aneurysms are treated appears to correlate with the economic development of European countries. It is probably also affected by the lack of experienced coilers in Eastern Europe.

The history of aneurysm therapy is rich in parallelisms that exist between the once-fledgling field of aneurysm surgery and the now-growing field of endovascular aneurysm treatment. The treatment of aneurysms has had a cyclic progression. The indirect and safest approach to the treatment of aneurysms was seen in the development and use of Hunterian ligation in the 19th century. During the past few decades, nascent technology and a better understanding of the pathophysiology of aneurysms resulted in a more direct intracranial, extravascular approach to aneurysm therapy, with the focal point being the use of the aneurysm clip to secure an aneurysm at its neck. Interestingly, alternative and, arguably, even more direct approaches to aneurysm therapy developed in the surgical suites. These techniques became the seeds for the birth of direct endovascular aneurysm treatment in particular and endovascular surgery in general. As endovascular technology continues to develop, somewhat more sophisticated, indirect approaches to aneurysm therapy (the use of stents to modify flow, for example) are being investigated. The treatment of intracranial aneurysms has a rich history. First thought to be inoperable lesions, aneurysms have challenged neurosurgeons and their colleagues since they were first recognized in the 18th century. Treatment for these lesions did not begin until the 19th century with the use of Hunterian ligation. This review describes the many milestones in the field of aneurysm surgery and endovascular surgery, tracing the many parallelisms contained within the birth and growth of each field and their respective significance.

Brain aneurysms are rare in the pediatric population. The diagnosis of a brain aneurysm in a child may be difficult because of its infrequency and often subtle or nonspecific clinical presentation. Endovascular therapy and microsurgical treatment are increasingly used approaches in treating children, possibly contributing to favorable outcomes if patients are treated in a timely manner. We were interested in the clinical presentation, symptoms, diagnostics, treatment, and follow-up of pediatric patients with brain aneurysms in Slovenia. This was a retrospective review of medical documentation of children with intracranial aneurysms treated at the University Children's Hospital in Ljubljana, Slovenia, from January 1998 to December 2017. We identified a cohort of eight children (median age: 14.9 years; range: 2.8-17.7). The estimated incidence of pediatric brain aneurysms in Slovenia is 0.12/100,000 children per year. We observed a male predominance (1.7:1). Half of the patients presented with acute onset of neurologic symptoms and three with subarachnoid hemorrhage. One of the patients had a related stroke. The presenting symptoms were tonic-clonic seizures, hemiparesis, paresthesias, speech disturbance, and cranial nerve palsy. The other half of aneurysms were identified incidentally. Five patients had anterior circulation aneurysms; the most prevalent location was the internal carotid artery. One patient was treated with surgical procedures, four patients were treated with endovascular procedures, and three patients were treated conservatively. Outcome was excellent in all patients. Endovascular interventions and microsurgical procedures appear to be safe and effective in the treatment of brain aneurysms in the pediatric population. Asymptomatic patients with brain aneurysms need close follow-up.

Reconstruction of the Basilar Tip with T Stent Configuration for Treatment of a Wide-Neck Aneurysm

The development of three-dimensional (3D) printing technology provides a new method for surgical treatment, but currently there are few reports on its application in the treatment of aneurysm. The aim of the present study was to explore the materials and methods of fabricating 3D printed individual aneurysm model and its value in the treatment of intracranial aneurysm. Twenty-four patients with intracranial aneurysm diagnosed by CTA who had undergone operation in our hospital were analyzed retrospectively. CTA Data collected at the time of surgery was used for reconstruction. Soft Mimics 17.0 was used to reconstruct the thin layer CTA scan data into 3D image and the final data was sent to the 3D printer for fabricating the model. We compared the proposed 3D printed model-based preoperative plan and the actual approach used in the surgery based on CTA data to evaluate the value of the 3D printed model in preoperative planning, and picked out the materials which were more suitable for the clinic. Twenty-four aneurysm models with high degree of reality were fabricated successfully with 3D-printing technology. The patients' blood vessels, skulls and aneurysms were printed into the reality model at a ratio of 1:1. It is reported that the soft material-based, 3D printed vascular and aneurysm model more closely resembled the characteristics of the real blood vessels, thus provides a better simulation compared to the plaster-based model. Compared with the original operation plan, 3D printed model could be used for pre-operative aneurysm clip selection, and provide more intuitive information in selection of operational approach. 3D printed model can be used as an operational physical model to design operative schemes, choose the best operative paths and select suitable aneurysm clips by its high simulation degree and individualized characteristics. The model is helpful for surgical planning, especially for the preoperative plan of treating refractory multiple aneurysms and giant aneurysms.

The authors report their experience using electrolytically detachable coils for the treatment of residual cerebral aneurysms following incomplete surgical clipping. Eight patients were treated for six anterior and two posterior circulation aneurysm remnants. All patients were referred for endovascular treatment by experienced cerebrovascular neurosurgeons at the authors' institution. Patients underwent follow-up angiography immediately after endovascular treatment. In seven of the eight patients, additional follow-up angiographic studies were obtained at periods ranging from 7 weeks to 2 years posttreatment. The latest follow-up angiograms demonstrated that six of the eight aneurysm remnants were 100% occluded, with near-complete occlusion of the other two aneurysm remnants. There was no permanent neurological or non-neurological morbidity or mortality associated with the treatment. There was no incidence of aneurysm hemorrhage during or after treatment. Endovascular treatment of cerebral aneurysm remnants following prior surgical clipping can be accomplished with acceptable morbidity and mortality rates. Endovascular coil occlusion can play an important adjunctive role in the treatment of those aneurysms that have been incompletely obliterated by surgical clipping.

The field of endovascular neurosurgery was paved by the work of a few creative “pioneers” who invented new delivery systems and new embolic agents capable of treating vascular diseases of...