Risk of Cerebral Aneurysm Rupture After Liver Transplantation: Development and Validation of a Hemorrhagic Stroke Scoring Model.

BACKGROUND: Liver transplantation (LT) patients appear to be more prone to neurological events compared to individuals undergoing other types of solid-organ transplantation. The aims of the present study were to analyze the prevalence of unruptured intracranial aneurysms (UIAs) in patients undergoing liver transplantation (LT) and to examine the perioperative occurrence of subarachnoid hemorrhage (SAH). Also, it intended to systematically identify the risk factors of SAH and hemorrhagic stroke (HS) within a year after LT and to develop a scoring system which involves distinct clinical features of LT patients. METHODS: Patients who underwent LT from January 2012 to March 2022 were analyzed. All included patients underwent neurovascular imaging within 6 months before LT. We conducted an analysis of prevalence and radiological features of UIA and SAH. The clinical factors that may have an impact on HS within one year of LT were also reviewed. RESULTS: Total of 3,487 patients were enrolled in our study after applying inclusion and exclusion criteria. The prevalence of UIA was 5.4%. The incidence of SAH and HS within one year following LT was 0.5% and 1.6%, respectively. We developed a scoring system based on multivariable analysis to predict the HS within 1-year after LT. The variables were a poor admission mental status, the diagnosis of UIA, serum ammonia levels, and Model for End-stage Liver Disease (MELD) scores. Our model showed good discrimination among the development (C index, 0.727; 95% confidence interval [CI], 0.635-0.820) and validation (C index, 0.719; 95% CI, 0.598-0.801) cohorts. CONCLUSION: The incidence of UIA and SAH was very low in LT patients. A poor admission mental status, diagnosis of UIA, serum ammonia levels, and MELD scores were significantly associated with the risk of HS within one year after LT. Our scoring system showed a good discrimination to predict the HS in LT patients.

Superficial temporal artery interposition bypass for the treatment of complex intracranial aneurysms: Flexible and creative options for flow preservation bypass.

PURPOSE: Flow-preservation bypass is a treatment option for complex intracranial aneurysms (IAs) that cannot be managed with microsurgical clipping or endovascular treatment. Various bypass methods are available, including interposition grafts such as the radial artery or saphenous vein. Size discrepancy, invasiveness, and procedure complexity must be considered when using interposition grafts. We describe our experience of treating complex IAs using a superficial temporal artery (STA) interposition bypass. METHODS: We retrospectively reviewed the medical records and operative videos of all patients who were treated for complex IAs at our center from January 2009 to December 2021 using cerebral revascularization. Clinical, radiological, and surgical findings of the cases that underwent STA interposition bypass were investigated. RESULTS: Seventy-six bypass procedures were performed of which seven (9.2%) complex IAs were managed using STA interposition bypass. Of these 5 cases were of anterior cerebral artery, 1 of middle cerebral artery, and 1 of posterior inferior cerebellar artery aneurysm. There were no postoperative ischemic complications. Revision surgery for postoperative pseudomeningocele was performed in one case. The long-term bypass patency rate was 85.7% (6 out of 7) and good long-term aneurysm control was achieved in all cases, with a mean follow-up of 64 months. CONCLUSIONS: When treating complex IAs, creative revascularization strategies are needed in selective cases for favorable outcomes. STA interposition graft bypass which can reduce the size discrepancy between the donor and recipient may be a less invasive, flexible, and practical option for treating complex IAs.

Clipping of Unruptured Anterior Choroidal Artery Aneurysms Together with Small Branches: Safety Confirmation Using Intraoperative Indocyanine Green Video-Angiography and Intraoperative Neurophysiological Monitoring.

BACKGROUND: In treating anterior choroidal artery (AChA) aneurysms, preserving the AChA main trunk is of course necessary to prevent postoperative ischemic complications. However, in practice, complete occlusions are often limited by small branches. OBJECTIVE: We aimed to demonstrate that even in cases where complete occlusion of the AChA aneurysm is complex due to small branches, complete occlusion can be safely achieved using indocyanine green video-angiography and intraoperative neurophysiological monitoring (IONM). METHODS: We performed a retrospective review of all unruptured AChA aneurysms surgically treated at our institution from 2012 to 2021. All available surgical videos were reviewed to find AChA aneurysms clipped with small branches; clinical and radiological data were collected for these cases. RESULTS: Among 391 cases of unruptured AChA aneurysms treated surgically, 25 AChA aneurysms were clipped with small branches. AChA-related ischemic complications occurred in 2 cases (8%) without retrograde indocyanine green filling to the branches. These 2 cases had changes in IONM. There were no ischemic complications in the remaining cases with retrograde indocyanine green filling to the branches and no change in IONM. During an average follow-up of 47 months (12-111 months), a small residual neck was observed in 3 cases (12%) and recurrence or progression of the aneurysm was observed in only 1 case (4%). CONCLUSIONS: The surgical treatment of AChA aneurysms carries the risk of devastating ischemic complications. Even in cases where complete clip ligation seems impossible due to small branches associated with AChA aneurysms, complete occlusion can be safely achieved using indocyanine green video-angiography and IONM.

Efficacy of intraoperative neuromonitoring (IONM) and intraoperative indocyanine green videoangiography (ICG-VA) during unruptured anterior choroidal artery aneurysm clipping surgery.

OBJECTIVE: The aim of this study was to investigate the efficacy of intraoperative indocyanine green videoangiography (ICG-VA) and intraoperative neuromonitoring (IONM) to prevent postoperative ischemic complications during microsurgical clipping of unruptured anterior choroidal artery (AChA) aneurysms. METHODS: We retrospectively reviewed the clinical and radiological records of all patients who had undergone microsurgical clipping for unruptured AChA aneurysms at our institution between April 2001 and December 2019. We compared the postoperative complication rate of the group for which intraoperative ICG-VA and IONM were utilized (group B; n=324) with that of the group for which intraoperative ICG-VA and IONM were not utilized (group A; n=72). RESULTS: There were no statistically significant differences in demographic data between the two groups. Statistically significant differences were observed in the rate of overall complications (p=0.014) and postoperative ischemic complications related to AChA territory (p=0.039). All the cases (n=4) in group B who had postoperative infarctions related to AChA territory showed false-negative results of intraoperative ICG-VA and IONM. CONCLUSIONS: Preserving the patency of the AChA is essential to minimize postoperative complications. Intraoperative monitoring tools including ICG-VA and IONM can greatly contribute to lowering complication rates. However, their pitfalls and false-negative results should always be considered.

Comparison of Visual Outcomes of Ophthalmic Artery Aneurysms Treated with Microsurgical Clipping and Endovascular Coiling.

PURPOSE: Post-treatment visual deficit is a major concern associated with both microsurgical clipping and endovascular coiling for the treatment of ophthalmic artery (OphA) aneurysms of the internal carotid artery. We aimed to compare the safety and effectiveness of the 2 modalities. MATERIALS AND METHODS: We retrospectively reviewed and compared the baseline characteristics and postoperative visual and angiographic outcomes of OphA aneurysms treated by clipping or coiling between January 2010 and August 2018 at our hospital. In addition, the balloon occlusion test was performed to evaluate the safety of OphA occlusion. RESULTS: This study included 56 aneurysms treated by clipping and 82 aneurysms treated by coiling. Both the immediate and follow-up rates of incomplete aneurysm occlusion were comparable between the 2 groups (21.4% vs. 22.0%; 24.4% vs. 23.6%). The incidence of post-treatment visual deficits was higher in the clipping group than in the coiling group (16.1% vs. 2.4%; P=0.010). We observed total ipsilateral OphA occlusion in 6 patients and near occlusion in 3 patients during endovascular coiling; however, only 1 patient with near OphA occlusion showed a post-treatment visual field defect. CONCLUSION: OphA aneurysms treated by endovascular coiling exhibited an aneurysm occlusion rate similar to that of microsurgical clipping with fewer post-treatment visual deficits. The total occlusion of OphA with adequate collaterals did not cause post-treatment visual deficits.

Role of microsurgery for treatment of posterior circulation aneurysms in the endovascular era.

OBJECTIVE: Several studies have reported that the outcomes of endovascular treatment were superior to those of microsurgical treatment for posterior circulation aneurysms. Thus, this study compared outcomes of endovascular and microsurgical treatment for posterior circulation aneurysms and assess the usefulness of microsurgery in these patients. METHODS: Outcomes were retrospectively evaluated after endovascular and microsurgical treatment of 621 posterior circulation aneurysms. The 621 aneurysms included 187 treated by surgical clipping and 434 treated by endovascular coiling. RESULTS: In patients with unruptured aneurysms the rates of residual lesions and retreatment were significantly lower in those who underwent microsurgical than endovascular treatment. However immediate postoperative and 6 month follow-up Glasgow outcome scale (GOS) scores did not differ significantly in the two groups. In patients with ruptured aneurysms, the rates of residual lesions and retreatment were significantly lower in the microsurgery than in the endovascular treatment group. Even so immediate postoperative and 6 month follow-up GOS scores did not differ significantly in the two groups. CONCLUSIONS: Endovascular treatment has increasingly become an alternative modality for microsurgery in posterior circulation aneurysm, whereas the indication for microsurgery is greatly reduced. However, the absolute number of microsurgery is maintained showing that it is a still valuable technique, as advances in endovascular or stent-assisted coiling have not solved many of the challenges inherent in the management of complex aneurysms. Hence, the advantages and limitations of both modalities must be carefully concerned in posterior circulation aneurysm to obtain favorable outcome.

Incidental Microaneurysms During Microvascular Surgery: Incidence, Treatment, and Significance.

BACKGROUND: Although new imaging tools have been developed for the detection of smaller aneurysms, angiographically negative microaneurysms are still encountered during cerebral microsurgery. Currently, only limited information regarding incidence and efficacy of treatment of these microaneurysms is available. METHODS: We investigated the incidence and treatment of incidental microaneurysms (IMAs) in the last 5 years. IMAs are unidentifiable and invisible on preoperative angiography, but are detected during microvascular surgery. The inclusion criteria were aneurysm cases treated with microsurgery via transsylvian approaches, and those undergoing preoperative digital subtraction angiography. RESULTS: This study enrolled 484 surgical cases (248 cases of subarachnoid hemorrhage and 236 cases of unruptured aneurysms) in 460 patients, and 33 tiny aneurysms were found in 31 operative cases (6.4% incidence per operation). The most typical type was located on another branching site of the middle cerebral artery found during neck clipping of the middle cerebral artery bifurcation aneurysm. A patient with multiple aneurysms presented a statistically significant risk (375/78 vs. 15/16; P < 0.001) of IMA identification. IMAs were treated by clipping and wrapping in 18 and 15 cases, respectively, without complications. CONCLUSIONS: This study revealed a 6.4% incidence of IMAs; however, this could be underestimated because of the limited range of inspection. Early detection of an IMA through careful inspection during microvascular surgery could be beneficial, especially in patients with multiple aneurysms.

Life-Threatening Hemothorax Caused by Spontaneous Extracranial Vertebral Aneurysm Rupture in Neurofibromatosis Type 1.

BACKGROUND: Although vascular abnormality is an uncommon comorbidity of neurofibromatosis type 1 (NF1), it is potentially fatal. We present spontaneous hemothorax caused by rupture of a vertebral artery (VA) aneurysm in a patient with NF1. CASE DESCRIPTION: A 36-year-old man with a history of NF1 was transferred to the emergency department with dyspnea. Chest computed tomography scan revealed hemothorax in the left lung field with mediastinal shifting and aneurysmal dilatation of the left VA at the C6 vertebra level. Immediate drainage of the hematoma by chest tube insertion was performed. Diagnostic angiogram showed a 3- to 4-cm fusiform aneurysm of the VA. After the angiogram, cardiopulmonary arrest occurred after a rebleed of the VA aneurysm. The aneurysmal segment of the VA was urgently occluded with detachable coils. Postoperatively, the patient was in intensive care for 1 month because of fulminant pneumonia. After the patient regained consciousness, he was found to have right hemiparesis from a small infarction at the pons. The patient's function improved to near normal after 1 year of recovery. CONCLUSIONS: Hemothorax caused by VA rupture in a patient with NF1 is an extremely rare condition that can be fatal. Careful examination with suspicion for early detection and treatment is required for this urgent condition. Endovascular coiling was safe even for an unstable patient with massive bleeding.

Characteristics of Peri-Internal Carotid Artery Bifurcation Aneurysms According to a New Anatomic Classification: How to Overcome Difficulties in the Microsurgical Treatment of Posteroinferiorly Projecting Carotid-A1 Junctional Aneurysms.

OBJECTIVE: Based on our clinical experience, posteroinferiorly projecting carotid-A1 junctional aneurysms are often difficult to treat microsurgically. Our objective was to classify peri-internal carotid artery (ICA) bifurcation aneurysms according to their location and analyze their characteristics. METHODS: From January 2008 to October 2017, microsurgical or endovascular treatment of 6777 aneurysms were performed at our hospital. We identified 199 peri-ICA bifurcation aneurysms (2.94%) classified into true ICA bifurcation aneurysm, carotid-A1 junctional aneurysm, and carotid-M1 junctional aneurysm according to the anatomic location. Medical records including patient characteristics, aneurysm location, surgical method, any neurologic deficits, clinical outcomes, medical history, and radiologic findings were retrospectively reviewed. The anatomic position of the aneurysm was defined from the virtual surgical, anteroposterior, and lateral views, and the degree of agreement was calculated. RESULTS: There were 103 true ICA bifurcation aneurysms, 92 carotid-A1 junctional aneurysms, and 4 carotid-M1 junctional aneurysms. Carotid-A1 junctional aneurysms tended to be smaller, elongated, and more often posteroinferiorly projecting than true ICA bifurcation aneurysms. Posteroinferiorly projecting carotid-A1 junctional aneurysms tended to require complex aneurysm surgery. The virtual surgical view had an almost perfect degree of agreement with the actual surgical view. CONCLUSIONS: The characteristics of carotid-A1 junctional aneurysms and true ICA bifurcation aneurysms differ. In particular, carotid-A1 junctional aneurysms tend to have a posteroinferior projection and that causes difficulty in surgical treatment. We recommend the virtual surgical view for preoperative planning. Furthermore, an adequate Sylvian fissure opening and a strategic approach using appropriate devices to inspect blind spots should be considered for a successful treatment outcome.

Pediatric Intracranial Aneurysms: Favorable Outcomes Despite Rareness and Complexity.

OBJECTIVE: Pediatric intracranial aneurysms (IAs) are rare and differ from their adult counterparts in terms of their aneurysmal characteristics, presentation, treatment, and outcomes. Their treatment is often more difficult and complex compared with that of adults. However, studies outlining the clinical effect of pediatric IAs remain sparse. METHODS: We retrospectively reviewed the data from patients aged ≤18 years admitted to our hospital from 2000 to 2017 with a diagnosis of IAs. RESULTS: From the sample of 8207 patients with an IA diagnosis, 26 patients with 33 IAs were involved. Our cohort included 17 males and 9 females, with a mean age of 12.5 years. The mean follow-up duration was 4 years and 3 months. Seven patients (26.92%) were assumed to have a traumatic origin for their IAs. Ruptured aneurysms were more common than unruptured ones (61.53% vs. 38.46%). Complex features were observed in 14 aneurysms (42.42%). Initially, microsurgical and endovascular treatment were both performed in 10 patients (38.46%). A good recovery was obtained in 16 patients (61.54%) as determined by the Glasgow outcome scale scores at the 6-month follow-up visits. The complete obliteration of aneurysms was observed in 17 patients (65.38%). Endovascular treatment was the initial treatment in 3 patients with incomplete obliteration. CONCLUSIONS: The treatment of pediatric IAs is challenging and technically demanding owing to their discrete nature compared with adult IAs and the need for greater surgical skills. We found a male predominance, with internal carotid artery bifurcation as the most frequent location of the aneurysms. Despite the greater incidence of ruptured and complex aneurysm cases, many patients had experienced a good recovery at the 6-month follow-up examinations.

Microsurgical treatment strategy for large and giant aneurysms of the internal carotid artery.

OBJECTIVE: We aimed to summarize our microsurgical treatment results for large (10-25 mm) and giant (≥25 mm) intradural internal carotid artery (ICA) aneurysms over a 7-year period at a single institution and to describe our detailed strategy. PATIENTS AND METHODS: We reviewed the records of 68 patients with 69 aneurysms, including large and giant intradural ICA aneurysms, treated using microsurgical techniques from January 2008 to December 2014. We used adenosine-induced cardiac standstill or retrograde suction decompression for some aneurysm clipping cases and performed bypass surgery if needed. RESULTS: Fifty-eight large and giant ICA aneurysms (84%) were treated with direct clipping, including 6 aneurysms (9%) clipped using adenosine-induced cardiac standstill and 10 aneurysms (14%) clipped using suction decompression. Eleven unclippable aneurysms (16%) were trapped with extracranial-intracranial bypass. Good or excellent results (modified Rankin Scale scores 0-2) were obtained in 47 patients with unruptured aneurysms (92%) and in 14 patients with ruptured aneurysms (82%) at the 6-month follow-up. Of 17 patients with visual disturbances before treatment, 11 (65%) had improved vision after surgical treatment. A remnant sac was found in 20 cases (29%) on digital subtraction angiography performed immediately postoperatively. At the median follow-up of 22 months, we encountered 3 recurrent aneurysm cases (5%) among the 58 aneurysms that were followed up. CONCLUSION: Our study demonstrated that microsurgical treatment of large and giant intradural ICA aneurysms remains competitive to flow-diverting treatment, if the surgeon is prepared to perform multifarious surgical methods, including adenosine administration, retrograde suction decompression, and bypass vascular anastomosis.

Intracranial Arterial Tortuosity According to the Characteristics of Intracranial Aneurysms.

OBJECTIVE: Intracranial aneurysm (IA) is the leading cause of subarachnoid hemorrhage. The pathomechanisms of IA are poorly understood but can be related to arterial tortuosity resulting from underlying systemic factors leading to arterial wall weakening. We aimed to analyze the tortuosity of the intracranial artery in a cohort with IA, hypothesizing that the tortuosity of intracranial arteries differs depending on the characteristics of the IA. METHODS: Patients with saccular IA were consecutively enrolled. Clinical factors and vascular tortuosity of the right and left middle cerebral arteries and basilar artery (BA) of all patients with IA were compared according to the characteristics of the IA: 1) ruptured versus unruptured, 2) multiple versus single, and 3) large (>5 cm) versus small (≤5 cm). Unruptured IAs were comparatively analyzed according to aneurysm size and aspect ratio, whereas ruptured IAs were analyzed according to aneurysm size. RESULTS: Two hundred eighty-five patients were enrolled (mean age, 59 years; 71.2% women). The tortuosity of the BA was higher in the large IA group (5.63 ± 6.26; n = 133; P = 0.009), large unruptured IA group (6.64 ± 6.32; n = 53; P = 0.039), and large ruptured IA group (5.50 ± 6.52; n = 80; P = 0.033) compared with the small IA, small unruptured IA, and small ruptured IA group. In multivariate analysis, increased BA tortuosity was significantly associated with large IAs (ß = 1.066; P = 0.008), unruptured large IAs (ß = 1.077; P = 0.033), and ruptured large IAs (ß = 1.086; P = 0.025). CONCLUSIONS: The BA tortuosity was higher in patients with large IAs, which may represent an imaging biomarker of aneurysm growth.

Intraoperative use of transcranial motor/sensory evoked potential monitoring in the clipping of intracranial aneurysms: evaluation of false-positive and false-negative cases.

OBJECTIVE: Somatosensory and motor evoked potentials (SEPs and MEPs) are often used to prevent ischemic complications during aneurysm surgeries. However, surgeons often encounter cases with suspicious false-positive and false-negative results from intraoperative evoked potential (EP) monitoring, but the incidence and possible causes for these results are not well established. The aim of this study was to investigate the efficacy and reliability of EP monitoring in the microsurgical treatment of intracranial aneurysms by evaluating false-positive and false-negative cases. METHODS: From January 2012 to April 2016, 1514 patients underwent surgery for unruptured intracranial aneurysms (UIAs) with EP monitoring at the authors' institution. An EP amplitude decrease of 50% or greater compared with the baseline amplitude was defined as a significant EP change. Correlations between immediate postoperative motor weakness and EP monitoring results were retrospectively reviewed. The authors calculated the sensitivity, specificity, and positive and negative predictive values of intraoperative MEP monitoring, as well as the incidence of false-positive and false-negative results. RESULTS: Eighteen (1.19%) of the 1514 patients had a symptomatic infarction, and 4 (0.26%) had a symptomatic hemorrhage. A total of 15 patients showed motor weakness, with the weakness detected on the immediate postoperative motor function test in 10 of these cases. Fifteen false-positive cases (0.99%) and 8 false-negative cases (0.53%) were reported. Therefore, MEP during UIA surgery resulted in a sensitivity of 0.10, specificity of 0.94, positive predictive value of 0.01, and negative predictive value of 0.99. CONCLUSIONS: Intraoperative EP monitoring has high specificity and negative predictive value. Both false-positive and false-negative findings were present. However, it is likely that a more meticulously designed protocol will make EP monitoring a better surrogate indicator of possible ischemic neurological deficits.

Intracranial Aneurysm Is Associated with High Intracranial Artery Tortuosity.

BACKGROUND: Although intracranial aneurysms (IAs) are focal bulges of arterial walls, an uncharacterized predisposing factor that affects cerebral arteries may increase tortuosity of intracranial arteries in patients with IAs. METHODS: Subjects who underwent routine health examinations and magnetic resonance angiography at a university hospital health promotion center were enrolled. Age- and sex-matched control subjects were selected from among individuals who did not have IAs. Tortuosity of right and left middle cerebral arteries and basilar artery (BA) was measured. Distant factor [(arc/chord ratio × 100) - 100] was used to estimate tortuosity. Vascular risk factors and intracranial arterial tortuosities were compared between subjects with IAs and control subjects. Independent factors associated with intracranial artery tortuosity were also investigated. RESULTS: Of 18,954 (1.9%) subjects, 367 exhibited IAs. The prevalence of hypertension (P = 0.01) and current smoking (P = 0.01) were higher in subjects with IAs than in control subjects. The BA tortuosity was greater in subjects with IAs compared with control subjects (9.0 ± 8.1 vs. 5.5 ± 7.2; P < 0.001). In addition to hypertension, smoking, and absence of coronary artery disease, BA tortuosity (P < 0.001) was independently associated with presence of IAs. The presence of IA (P < 0.001) and absence of coronary artery disease (P = 0.002) were independently associated with high BA tortuosity. CONCLUSIONS: Patients with IAs exhibit a more tortuous BA. A predisposing factor weakening the cerebrovasculature in patients with IAs may exist and may manifest as high tortuosity of intracranial arteries.

Neurologic Deterioration in Patients with Moyamoya Disease during Pregnancy, Delivery, and Puerperium.

BACKGROUND: We reviewed our clinical experience of patients with moyamoya disease (MMD) who gave birth and assessed characteristics of those experiencing neurologic deterioration. METHODS: The patients were classified into patients diagnosed with MMD during pregnancy and puerperium (group 1) and those diagnosed before pregnancy (group 2). We retrospectively reviewed patient characteristics, MMD treatment, neurologic symptoms before and during pregnancy and/after puerperium, obstetrical history, and delivery type in groups 1 and 2. RESULTS: Group 1 included 2 patients with deterioration of pre-existing transient ischemic attacks (TIAs) and acute cerebral infarction and 1 patient with seizures and newly developed TIAs during pregnancy and/or puerperium. Group 2 included 20 patients with 23 pregnancies. In group 2, 4 patients had deterioration of TIAs during pregnancy and puerperium. There were significant differences between the cases without neurologic deterioration and with deterioration in group 2 (TIAs ≥10 before pregnancy, 0% vs. 75%, P = 0.002; severely reduced regional cerebrovascular reserve on single-photon emission computed tomography, 10.5% vs. 100%, P = 0.002; and surgical revascularization before pregnancy, 75% vs. 15.8%, P = 0.04). In groups 1 and 2, 6 of the 7 cases in which TIAs occurred or worsened during pregnancy or puerperium recovered to prepregnancy TIA levels after puerperium. CONCLUSIONS: Patients with severely reduced regional cerebrovascular reserve on single-photon emission computed tomography and frequent TIAs before pregnancy may experience neurologic deterioration during pregnancy, delivery, and puerperium. Surgical revascularization before pregnancy may decrease neurologic deterioration during these periods.

Surgical Revascularization for the Treatment of Complex Anterior Cerebral Artery Aneurysms: Experience and Illustrative Review.

BACKGROUND: Many methods for treating complex anterior cerebral artery (ACA) aneurysms are available; however, there is substantial variation among methods because of various aneurysm locations, the relationship of the aneurysm to arterial branches, aneurysm size and other morphologic characteristics, and the diameters of the parent or branching arteries. METHODS: We reviewed complex ACA aneurysms based on both our own experience and the available literature. Each unique case is analyzed in terms of the characteristics of the aneurysm, along with analysis and classification of the revascularization method used. Computer tablet-drawn illustrations of each unique technique are provided for comprehension and application in various situations. RESULTS: Over 6 years, we treated 5 cases of complex ACA aneurysms (1 precommunicating, 1 communicating, 1 postcommunicating, and 2 precallosal-supracallosal segment) with revascularization. Side-to-side anastomoses included pericallosal ACA segment-pericallosal ACA segment in 3 cases, supracallosal ACA segment-supracallosal ACA segment in 1 case, and ipsilateral callosomarginal artery-pericallosal artery in 1 case. Final modified Rankin scale score was 0 in 4 of 5 cases and 3 in 1 case. Six treatment strategies were used for the precommunicating aneurysm, 8 for the communicating aneurysm, 7 for the postcommunicating aneurysm, and 9 for the 2 precallosal-supracallosal segment aneurysms. CONCLUSIONS: Treatment of complex ACA aneurysms should be tailored according to the location and nature of the aneurysm and collateral circulation. Viable and feasible treatment strategies must be established by the neurovascular surgeon.

Intraprocedural Rupture of Unruptured Cerebral Aneurysms During Coil Embolization: A Single-Center Experience.

OBJECTIVE: Incidence of intraprocedural rupture (IPR) during endovascular coiling is reported to be 2%-5%. We reviewed a single-center experience of IPR during coil embolization of unruptured intracranial aneurysms. METHODS: Between January 2011 and April 2016, 849 patients were treated with endovascular therapy for unruptured intracranial aneurysm. IPR was documented in 10 (1.18%) of these patients. We reviewed medical records to evaluate characteristics of the aneurysms, angiographic findings related to rupture, management, and outcomes. RESULTS: Among the 10 patients, there were 4 internal carotid artery aneurysms, 3 anterior communicating artery aneurysms, 2 basilar tip aneurysms, and 1 middle cerebral artery aneurysm. The probable mechanism of IPR in 7 patients was focal coil mass distention. Two patients underwent rupture owing to injury by a microcatheter tip that was related to device-device interaction. In 1 patient who had no other clear etiology, increased intra-arterial pressure induced by contrast injection was suspected as a cause of rupture. In all cases, rapid occlusion at the point of suspected leakage was performed, and final angiography showed complete obliteration of the aneurysm. After the procedure, neurologic deterioration was demonstrated in 2 patients. The modified Rankin Scale score at 6-month follow-up was 0 in 7 of the patients. CONCLUSIONS: Incidence of IPR during endovascular coiling of unruptured aneurysms is relatively low. Early detection followed by rapid occlusion of the aneurysm can lead to a benign clinical course in most cases.

Treatment of Large and Giant Middle Cerebral Artery Aneurysms: Risk Factors for Unfavorable Outcomes.

OBJECTIVE: This study aimed to assess the clinical and radiologic outcomes after neurosurgical treatment of large and giant aneurysms of the middle cerebral artery (MCA). In addition, we aimed to identify risk factors for unfavorable outcomes. METHODS: This retrospective study included 105 patients with 106 large or giant MCA aneurysms treated with neurosurgical methods, including microsurgery and endovascular treatment, over a 15-year period. RESULTS: The mean aneurysm size was 15.3 ± 7.1 mm. Ten (9.4%) were giant aneurysms. The MCA bifurcation was the most common aneurysm site, followed by the MCA trunk and distal MCA. Aneurysm clipping was the most common treatment method, followed by clipping or trapping with bypass surgery and endovascular treatment. However, acute cerebral infarction was the most common complication (16.0%), poor outcomes (modified Rankin Scale score, 3-6) developed in 12.3% of aneurysms after treatment, and 6.6% of treated aneurysms needed retreatment. Multivariate analysis showed that independent risk factors for acute cerebral infarction after treatment were aneurysms located on the MCA trunk and 2 or more underlying diseases. Initial presentation with subarachnoid hemorrhage and complications during treatment were independent risk factors for poor outcomes. In addition, endosaccular coiling was an independent risk factor for retreatment. CONCLUSIONS: Neurosurgical management should be considered a priority for large and giant MCA aneurysms because of the high rupture rate and clinical symptoms. However, treatment outcomes remain unsatisfactory. Therefore, tailored management with consideration of risk factors for unfavorable outcomes should be implemented.

Treatment Strategy Based on Experience of Treating Intracranial Infectious Aneurysms.

OBJECTIVE: Intracranial infectious aneurysms (IIAs) are a rare but unique subtype of potentially life-threatening vascular lesion. However, there is no widely accepted standard protocol for their management. We reviewed our treatment experiences of IIAs from 2001 to 2015 and proposed a treatment strategy for future use. METHODS: We retrospectively reviewed 25 patients with 33 IIAs. All patients had predisposing infectious disease for which the causative organism had been identified. RESULTS: There were 12 patients with ruptured IIAs and 13 with unruptured IIAs. Of these patients, 17 (68%) had infective endocarditis, and viridans group streptococci (40%) were the most common causative organisms. All patients underwent antibiotic therapy, and 17 IIAs in 13 patients resolved with intravenous antibiotic therapy. However, 16 IIAs in 12 patients required neurosurgical treatment, including parent artery occlusion with glue or coils, endosaccular coiling, or microsurgery. The mean size of IIAs that responded to intravenous antibiotics (4.1 ± 2.2 mm) was smaller than that for IIAs with no response (7.5 ± 3.1 mm) (P = 0.01). Two patients had treatment-related complications: an acute cerebral infarction after parent artery occlusion and a rupture of the IIA during antibiotic therapy. There was no recurrence or mortality. CONCLUSIONS: All patients with IIAs should undergo appropriate antibiotic therapy. In cases with unruptured IIA, patients can be managed using medical therapy with antibiotics alone for 4-6 weeks. However, neurosurgical treatment should be considered in cases of ruptured IIA or unruptured IIA that do not respond to antibiotic therapy.