Review of Temporary Arterial Clipping in Intracranial Aneurysm Surgery: Historical Insights, Current Techniques, and Future Directions

The intra-operative rupture of intracranial aneurysms (IA) occurs in 5–30% of cases as reported in the literature. This event is frequently associated with an increase in mortality and morbidity. The aim of this study was to evaluate the prognostic importance of temporary clipping in intracranial aneurysm surgery. A series of 304 cases of IA treated surgically were selected by excluding giant or Hunt-Hess grade >3 aneurysms. Two groups of patients were compared: one of 157 cases that had temporary clipping (TC) during surgery and the other of 147 patients who did not have TC. The neuroprotective measures used were the infusion of Thiopental and maintenance of adequate blood pressure by use of Bitartrate Metaraminol and Ephedrine. The surgical complications, chiefly intra-operative rupture of the sac and consequences of malpositioning the clip with associated clinical complications, were considered. The two groups were compared using χ2 that showed a statistically significant reduction of the surgical complications in those patients who had TC. The associated poor clinical outcome was reduced from 7.5% to 2.5%. The main prognostic factor in determining the ischemic damage was the occlusion time of the local arterial circulation. The mean occlusion time in these patients was limited to four minutes and in only 12 cases reached 15–16 minutes without ischemic complications. Temporary clipping reduces the risk of intra-operative rupture of aneurysm and permits a better dissection of the sac with an adequate positioning of the definitive clip. In cases of small aneurysm with an easily accessible neck (that predict a temporary occlusion of the local arterial circulation) we consider the maintenance of optimal blood pressure very important. However we do not consider it essential to use electrophysiologic monitoring or other particular techniques of neuroprotection (which are vital in the surgery of giant or complex aneurysms).

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

It is important to prevent intraoperative aneurysm rupture in patients with ruptured cerebral aneurysms, because intraoperative bleeding can have catastrophic consequences. It is very useful for aneurysm surgeons trying to prevent this complication to know the incidence of intraoperative ruptures, the clinical grades and the location of aneurysms in which they occur and, when during operations intraoperative ruptures occur most frequently. We evaluated 905 of our patients with ruptured cerebral aneurysms and discussed the prevention of intraoperative rupture.Intraoperative aneurysm rupture was noted in 117 cases (13%). That rate was significantly higher in cases with middel cerebral artery aneurysms, anterior communicating artery aneurysms and anterior cerebral artery aneurysms than in those with internal cerebral artery aneurysms and vertebrobasilar artery aneurysms. The incidence was significantly higher in cases undergoing surgery on Day 0 to 3 and 8 to 14 than on Day 4 to 7 and after Day 15. The intraoperative bleeding rate was also significantly higher in cases with Hunt and Kosnik Grade III to V than in those with I to II. The rate of intraoperative hemorrhage was significantly lower in cases enduring temporary occlusion to prevent intraoperative bleeding than in those without temporary clipping. Over 90%of the intraoperative rupture occurred at the timing of aneurysm dissection and application of clips.Temporary clipping effectively prevents intraoperative bleeding. That should be followed by aneurysmal dissection with sharp microsurgical technique, when the intraoperative rupture may most likely occur due to the aneurysm tightly adhering to the surrounding tissues and its thinned and reddened wall. Especially, temporary clips should be used in clinical grade III to V patients with aneurysms in the anterior communicating artery, the distal anterior cerebral artery or the middle cerebral artery, who undergo surgery on Day 0 to 3 or Day 8 to 14.To avoid aneurysm rupture when retracting the frontal lobe, methods to decrease the retractor pressure should be devised. And the brain spatula should be pulled in the proper direction according to the position of aneurysms, involving the direction of aneurysmal domes, the location of blebs, and these possible adherence to the surrounding tissue. As insufficient dissection of the neck causes bleeding in clip application, it should be remembered that the aneurysmal neck must be sufficiently dissected from the surrounding tissue with temporary clipping. A wrapping aneurysm clip should be applied for a blister-like aneurysm in the anterior wall of the internal cerebral artery.

The aim was to analyze the risk factors for intraoperative rupture (IR) of cerebral aneurysm and for temporary clips (TC) use, as well as their influence on the final postoperative outcome. Retrospective study was done 72 IR patients, and on 75 TC patients. For patients with or without IR, as well as for the patients with or without TK, outcome of the treatment, aneurysm size and localization, preoperative clinical state and operative timing was analyzed, and statistical significance of obtained differences was tested. IR occurred in 40% of anterior cerebral artery aneurysms and in 16.7% of internal carotid artery aneurysms (p > 0.05), while TCs were used in 52% of middle cerebral artery aneurysms and 34.8% of internal carotid artery aneurysms (p > 0.05). Average size was 17.3 mm for aneurysms with IR and 11.7 mm for those without IR (p > 0.05). Aneurysms were significantly larger in patients with TCs, than in patients without TCs (16.7 mm and 9.4 mm respectively, p < 0.05). Preoperative period was 10.2 days for patients with IR, and 16.8 days for patients without IR (p < 0.05). Favorable outcome was observed in 71.4% of patients with IR and in 70.6% of those without IR, as well as in 76.4% of patients who required TC and in 75.6% of cases without TC (p > 0.05). Average duration of temporary occlusion was 5.8 min for patients with favorable outcome and 15 min for patients with poor outcome (p < 0.05). Incidence of IR mostly depended on the duration of preoperative interval, while the frequency of TC use depended mostly on aneurysm size. IR did not influence the surgical outcome, as well as TC use, if the occlusion was shorter than 8-10 min.

OBJECTIVE The purpose of this study was to analyze the impact of adenosine-induced cardiac arrest (AiCA) on temporary clipping (TC) and the postoperative cerebral infarction rate among patients undergoing intracranial aneurysm surgery. METHODS In this retrospective matched-cohort study, 65 patients who received adenosine for decompression of aneurysms during microsurgical clipping were identified (Group A) and randomly matched with 65 selected patients who underwent clipping but did not receive adenosine during surgery (Group B). The matching criteria included age, Fisher grade, aneurysm size, rupture status, and location of aneurysms. The primary outcomes were TC time and the postoperative infarction rate. The secondary outcome was the incidence of intraoperative aneurysm rupture (IAR). RESULTS In Group A, 40 patients underwent clipping with AiCA alone and 25 patients (38%) received AiCA combined with TC, and in Group B, 60 patients (92%) underwent aneurysm clipping under the protection of TC (OR 0.052; 95% CI 0.018-0.147; p < 0.001). Group A required less TC time (2.04 minutes vs 4.46 minutes; p < 0.001). The incidence of postoperative lacunar infarction was equal in both groups (6.2%). There was an insignificant between-group difference in the incidence of IAR (1.5% in Group A vs 6.1% in Group B; OR 0.238; 95% CI 0.026-2.192; p = 0.171). CONCLUSIONS AiCA is a useful technique for microneurosurgical treatment of cerebral aneurysms. AiCA can minimize the use of TC and does not increase the risk of IAR and postoperative infarction.

BackgroundDistal intracranial aneurysms are often located deep in the lateral or longitudinal fissure pool or brain parenchyma, lacking a fixed anatomical location. Precise intraoperative localization of distal intracranial aneurysms is a problem that plagues neurosurgeons. Studies have shown that neuronavigation and Computed Tomography (CT) three-dimensional angiography can significantly improve the accuracy of intracranial aneurysm surgery. However, their values in the distal intracranial aneurysm surgery remain unknown. The objective of this study was to explore the application value of neuronavigation combined with CT three-dimensional angiography in distal intracranial aneurysm surgery.Methods112 patients admitted to our hospital for intracranial distal aneurysm surgery were retrospectively collected and divided into an observation group (n=51) and a control group (n=61) according to the surgical method received by the patients. The observation group underwent clipping treatment based on neuronavigation combined with CT three-dimensional angiography, and the control group received clipping treatment under the guidance of CT angiography. Both groups were observed for the accuracy of localization and approach design, duration of surgery, intraoperative bleeding volume, Glasgow Outcome Scale (GOS), National Institute of Health Stroke Scale (NIHSS), length of hospital stay, and complications.ResultsCompared with the control group, the localization accuracy of patients in the observation group was significantly increased (94.12% vs. 78.69%, P=0.020), and the accuracy of approach design was markedly improved (90.20% vs. 72.13%, P=0.017). Furthermore, the length of hospital stay in the observation group was notably reduced compared with the control group (8.12±2.12 vs. 8.99±1.87 d, P=0.023). There was no statistical difference in the NIHSS scores between the two groups before treatment and at 3 days after treatment (P>0.05). However, compared with the control group, the NIHSS score was significantly reduced in the observation group at 28 days after surgery (4.10±2.48 vs. 6.30±3.20, P=0.000). There were no statistically significant postoperative complications in either group (P>0.05).ConclusionsNeuronavigation combined with CT three-dimensional angiography can enhance the accuracy of localization and approach design in intracranial distal aneurysm surgery, improve patient nerve function, and is worth promoting.

Temporary Artery Occlusion in Aneurysm Surgery: Patients with Subarachnoid Hemorrhage

Background: Neurosurgery's challenging area involves addressing intracranial aneurysms, given the high morbidity and mortality rates associated with them. Safe clipping, a technique that involves the intraoperative temporary occlusion of the arterial supply, is generally used. However, a focused review on the evolution of temporary clipping in intracranial aneurysms hasn't been previously carried out. Methods: We performed a comprehensive literature search on PubMed Medline and Google Scholar, using the combination of terms: [Temporary clip* AND (Cerebral OR Intracranial) Aneurysm]. Results: From an initial pool of 579 results, we excluded unrelated papers, narrowing it down to 25 relevant studies. These ranged from retrospective and prospective studies on the outcome favorability or radiological evidence, to analyses on potential independent prognostic factors, and articles related to the history and evolution of temporary clipping. Conclusion: Temporary arterial occlusion in aneurysm surgery has evolved significantly since its inception in the early 20th century, marked by innovations in instruments and temporary clips. Despite these advancements, the utility and safety of temporary clips continue to be topics of discussion, particularly due to concerns regarding possible complications and their influence on long-term results.

BackgroundTemporary artery occlusion is an important technique during the microsurgical repair of cerebral aneurysms. Parent vessel temporary clipping facilitates safe aneurysm dissection and easier mobilization, and may soften the aneurysm...

Introduction Intraoperative rupture (IOR) is the most anticipated yet dreaded complication during intracranial aneurysmal surgery, leading to severe adverse outcomes. This study aims to analyze various risk factors contributing to IOR. MethodsIt was an analytical study of 46 cases of intracranial aneurysms treated at Department of Neurosurgery, Bir Hospital including both ruptured (n=43) and unruptured (n=3) aneurysms. Incidence of IOR, demographic data, preoperative grading scales, aneurysm morphology, phases and severity of IOR along with postoperative complications and outcomes were assessed. ResultsIOR occurred in 28.26% (13/46) cases of intracranial aneurysms. Most common aneurysm was anterior communicating artery aneurysm (43.5%, 20/46) with majority of IOR (65.1%).Younger patients and males had higher rates of IOR, and early surgical intervention (within 72 hours) was associated with increased incidence (69.2%,9/13). Although preoperative factors showed no direct correlation with IOR, aneurysm size and morphology-dome width and height ratio (W/H) and irregular shapes of aneurysm emerged as critical risk factors (p&lt;0.05). Temporary clipping during surgery appeared to reduce IOR, mostly mild (13.04%, 6/13) and occurred in second phase (17.39%; 8/13, during microdissection and neck preparation). However, IOR did not have adverse effects on postoperative complications and Glasgow Outcome Scale Extended (GOSE) at discharge. ConclusionIncidence of IOR was 28.65%. Younger age, males, higher Fisher score, early timing of surgery of aneurysms and larger size increased the risk, while use of temporary clip reduced the risk. Dome H/W ratio and irregular shapes of aneurysm were important factors predicting IOR in this study.

Factors associated with blood transfusion during intracranial aneurysm surgery

Background: Few studies have evaluated the adenosine dose that induces cardiac arrest during intracranial aneurysm surgery. We present our experiences with adenosine-induced transient asystole (AiTA) during intracranial aneurysm surgery and dosage recommendations.Methods: We retrospectively reviewed the medical records of all patients who underwent intracranial aneurysm surgery between July 2016 and December 2018. Patients who experienced AiTA during intracranial aneurysm surgery were included in the study.Results: Our study included nine intracranial aneurysm surgeries performed in eight patients. Thirteen episodes of AiTA were reported. Five of these were performed to facilitate bleeding control due to intraoperative aneurysm rupture (IAR), and adenosine doses were 9 mg (0.20 mg/kg), 12 mg (0.25 mg/kg), 12 mg (0.26 mg/kg), 18 mg (0.34 mg/kg), and 18 mg (0.39 mg/kg), resulted in transient asystole for 12, 14, 9, 44, and 18 s, respectively. For episodes without IAR, adenosine doses ranging from 6 to 18 mg (0.11–0.39 mg/kg) caused asystole for 8–33 s. In five episodes without IAR, low-dose adenosine (lower than 0.2 mg/kg) was used and caused asystole ranging from 8 to 12 s. Postoperatively, two patients had elevated cardiac troponin T levels but normal electrocardiograms.Conclusion: AiTA can facilitate the clipping of intracranial aneurysms at low-risk of serious cardiac complications. An adenosine dose of 0.2–0.4 mg/kg is safe and effective in both IAR and non IAR situations. In non IAR cases, we propose that low-dose AiTA is an option to facilitate aneurysm clipping. A starting dose of 6 mg or 0.1–0.2 mg/kg can adequately induce brief asystole by softening the aneurysmal sac during clip application.

Single photon emission computed tomography with technetium-99m-d, l-hexamethylpropyleneamineoxime was used to assess variations in regional cerebral blood flow during temporary clipping in the course of intracranial aneurysm surgery and during the postoperative period in 20 patients, 14 of whom underwent temporary clipping. Of these 14 patients (Group A), 9 had aneurysms of the anterior communicating artery, 2 had aneurysms of the middle cerebral artery, and 3 had aneurysms of the carotid siphon. Temporary clips were applied, according to the site of the lesion, on A1, on the trunk of the middle cerebral artery, or on the trunk of the internal carotid artery. The occlusion time ranged from 2 to 31 minutes. The six patients who did not undergo temporary clipping served as controls (Group B), as follows: three had aneurysms of the posterior communicating artery, one of the anterior communicating artery, one of the middle cerebral artery, and one of the internal carotid artery. All patients were investigated with cerebral single photon emission computed tomography preoperatively, perioperatively, and postoperatively. In all the patients of Group A, the preliminary results of the study show a sharp fall in the perfusion of the territories of the temporarily clipped parent vessel and practically a complete recovery within 2 to 7 days of surgery, with no significant neurological symptoms. No similar disturbance of perfusion was found in the patients of Group B.

SINGLE PHOTON EMISSION computed tomography with technetium-99m-d, l-hexamethylpropyleneamineoxime was used to assess variations in regional cerebral blood flow during temporary clipping in the course of intracranial aneurysm surgery and during the postoperative period in 20 patients, 14 of whom underwent temporary clipping. Of these 14 patients (Group A), 9 had aneurysms of the anterior communicating artery, 2 had aneurysms of the middle cerebral artery, and 3 had aneurysms of the carotid siphon. Temporary clips were applied, according to the site of the lesion, on A1, on the trunk of the middle cerebral artery, or on the trunk of the internal carotid artery. The occlusion time ranged from 2 to 31 minutes. The six patients who did not undergo temporary clipping served as controls (Group B), as follows: three had aneurysms of the posterior communicating artery, one of the anterior communicating artery, one of the middle cerebral artery, and one of the internal carotid artery. All patients were investigated with cerebral single photon emission computed tomography preoperatively, perioperatively, and postoperatively. In all the patients of Group A, the preliminary results of the study show a sharp fall in the perfusion of the territories of the temporarily clipped parent vessel and practically a complete recovery within 2 to 7 days of surgery, with no significant neurological symptoms. No similar disturbance of perfusion was found in the patients of Group B.

Temporary vessel occlusion is an effective technique used by microvascular surgeons to facilitate dissection and permanent clipping of cerebral aneurysms. Prolonged temporary occlusion carries the risk of infarction in the territory distal to the point of occlusion. The risk of infarction can be reduced by reducing the oxygen requirements of the brain and by maintaining collateral circulation by means of blood pressure control. We studied the effects in 90 patients of etomidate + mannitol or thiopental + mannitol usage during temporary clipping in aneurysm surgery on SjVO2. group 1 received thiopental + mannitol and group 2 received etomidate + mannitol for protection before temporary clipping. After normalization of blood pressure (mild hypertension, mean arterial pressure 90-110 mm Hg) a temporary clip was used. Blood samples were taken from the jugular venous bulb catheter to assess SjVO2 at intervals during the procedure. Postoperative radiologic and clinical ischemia were evaluated with a CT scan and neurologic examination. In group 1, 6 patients were given inotropic agent infusion to maintain mean arterial pressure. However, in group 2, the inotropic agent was not required. SjVO2 values increased more than 80% in 1 patient in group 1 and in 2 patients in group 2. A new radiographic stroke was observed in 2 patients in group 2. When etomidate + mannitol was used for protection before temporary clipping, cerebral infaction appeared to be permanent as a result of the prolonged occlusion time. The results of this clinical study need further investigation.