The Relationship Between Carotid Artery Stenosis and the Development of Open-Angle Glaucoma: A Long-term Cohort Study in Taiwan.

PURPOSES: To determine the relationship between carotid artery stenosis (CAS) and the development of open-angle glaucoma (OAG) in the Taiwanese population. METHODS: This retrospective cohort study was conducted using Chang Gung Research Database. Cox-proportional hazards model was applied to calculate the hazard ratio for OAG between CAS and the control cohort. RESULTS: Among 19,590 CAS patients, 17,238 had mild CAS (<50%), 1,895 had moderate CAS (50-69%), and 457 had severe CAS (≥70%). The CAS cohort had a higher proportion of several comorbidities. After adjusting for comorbidities, no significant difference in OAG development was found between CAS and control cohorts. Matching for key comorbidities, no significant differences in OAG incidence were found between matched cohorts (P = .869). Subdividing the matched CAS cohort by stenosis severity: mild (<50%), moderate (50-69%), and severe (≥70%), a statistically significantly lower OAG risk was observed in patients with mild CAS stenosis (HR: 1.12, 95% CI = 1.03-1.21, P = .006). Kaplan-Meier analysis revealed reduced OAG incidence in CAS patients who underwent surgical intervention, compared to the control cohort (P <.001). Subgroup analysis revealed that patients in the mild CAS stenosis group, those who underwent surgical intervention exhibited a reduced OAG risk (HR: 0.29, 95% CI = 0.15-0.58, P = .001). CONCLUSIONS: No statistically significant differences in OAG risk were observed between patients with CAS and the control cohort. The severity of CAS appears to influence OAG risk, with surgical intervention potentially offering protective effects, particularly in patients with mild CAS stenosis (<50%), suggesting that enhanced ocular perfusion post-surgery may act as a protective factor against OAG development.

Comparison of the treatment strategies for symptomatic chronic internal carotid artery occlusion.

OBJECTIVE: The best management of symptomatic chronic internal carotid artery occlusion (CICAO) has been controversial. This systematic review and meta-analysis were to compare the outcomes of different treatment strategies for symptomatic CICAO. METHODS: Two independent researchers conducted a search of articles on the treatment of CICAO published between January 2000 and October 2023 in PubMed, Web of Science, Embase, and The Cochrane Library. Twenty-two articles were eligible for meta-analysis using a random effects model to combine and analyze the data for the pooled rates of stroke and death, and the rates of procedural success and significant restenosis/occlusion. RESULTS: A total of 1193 patients from 22 publications were included in this study. Six of them had bilateral internal carotid artery occlusion. The 30-day stroke and death rates were 1.1% (95% confidence interval [CI], 0%-4.4%) in the best medical treatment (BMT) group, 4.1% (95% CI, 0.7%-9.3%; I2 = 71.4%) in the extracranial-intracranial (EC-IC) bypass group, 4.4% (95% CI, 2.4%-6.8%; I2 = 0%) in the carotid artery stenting (CAS) group, and 1.2% (95% CI, 0%-3.4%; I2 = 0%) in the combined carotid endarterectomy (CEA) and stenting (CEA + CAS) group. During follow-up of 16.5 (±16.3) months, the stroke and death rates were 19.5%, 1.2%, 6.6%, and 2.4% in the BMT, EC-IC, CAS, and CEA + CAS groups respectively. The surgical success rate was 99.7% (95% CI, 98.5%-100%; I2 = 0%) in the EC-IC group, 70.1% (95% CI, 62.3%-77.5%; I2 = 64%) in the CAS group, and 86.4% (95% CI, 78.8%-92.7%; I2 = 60%) in the CEA + CAS group. The rate of post-procedural significant restenosis or occlusion was 3.6% in the EC-IC group, 18.7% in the CAS group, and 5.7% in the CEA + CSA group. The surgical success rate was negatively associated by the length of internal carotid artery (ICA) occlusion. Surgical success rate was significantly higher in the patients with occlusive lesion within C1 to C4 segments, compared with those with occlusion distal to C4 segment (odds ratio, 11.3; 95% CI, 5.0-25.53; P < .001). A proximal stump of ICA is a favorable sign for CAS. The success rate of CAS was significantly higher in the patients with an ICA stump than that in the patients without (odds ratio, 11.36; 95% CI, 4.84-26.64; P < .01). However, the success rate of CEA + CAS was not affected by the proximal ICA stump. CONCLUSIONS: For the management of symptomatic CICAO, BMT alone is associated with the highest risk of mid- and long-term stroke and death. EC-IC bypass surgery and CEA + CAS should be considered as the choice of treatment based on operator's expertise and patient's anatomy. CAS may be employed as an alternative option in high surgical risk patients, especially when proximal ICA stump exists.

[EC-IC bypass for occlusion of the internal carotid artery]. / EC-IC-Bypass bei Verschluss der A. carotis interna.

BACKGROUND: There are barely any alternative treatment options to the drug treatment of hemodynamically caused cerebral ischemia, as in occlusion of the internal carotid artery. OBJECTIVE: For secondary prevention of an ischemic stroke due to carotid occlusion and hemodynamic instability, extracranial-intracranial (EC-IC) bypass surgery can be an important option in selected patients. MATERIAL AND METHODS: The development, study situation, indications and surgical technique for placement of an EC-IC bypass in cases of occlusion of the internal carotid artery are presented. RESULTS: With appropriate expertise and strict selection of patients, the placement of an EC-IC bypass enables stabilization of cerebral perfusion with a low rate of complications. CONCLUSION: The study situation is controversially discussed; nevertheless, surgical treatment in a specialized neurovascular center should at least be considered.

Effect of revascularization surgery on cerebral hemodynamics in adult moyamoya disease.

OBJECTIVE: Few studies have reported local hemodynamic changes after revascularization surgery. This study aimed to identify regional hemodynamic changes after combined revascularization surgery for moyamoya disease using single-photon emission computed tomography with N-isopropyl-p-123I-iodoamphetamine. METHODS: A total of 46 adults with moyamoya disease who underwent combined revascularization surgery from August 2009 to July 2021 at our facility were enrolled. The combined bypass procedure comprised a single direct bypass to the motor area and encephalo-duro-arterio-myo-synangiosis. The preoperative and postoperative cerebral blood flow (CBF) and cerebral vascular reserve (CVR) in the genu; precentral, central, parietal, angular, temporal, and posterior regions; splenium; hippocampus; and cerebellum were measured. To modify the examination variability, the cerebral-to-cerebellar activity ratio (CCR) was calculated by dividing the counts in the region by those in the cerebellum (CBF-CCR and CVR-CCR). RESULTS: Postoperatively, asymptomatic cerebral infarction occurred in three (6.5%) patients. The CBF-CCR and CVR-CCR improved in the precentral, parietal, and temporal regions and in the overall middle cerebral artery (MCA) territory. Sub-analysis of anterior cerebral artery (ACA) and posterior cerebral artery (PCA) territory hemodynamics revealed that patients with normal preoperative hemodynamics showed no changes in the CBF-CCR and CVR-CCR postoperatively, whereas patients with preoperative perfusion impairment exhibited improved CVR-CCR in the ACA territory (0.13-0.3, p=0.019) and CBF-CCR in the PCA territory (0.93-0.96, p=0.0039). CONCLUSION: Combined revascularization surgery with single bypass to the motor area improved hemodynamics in the primary targeted MCA territory and in the ACA and PCA territories among patients with preoperative hemodynamic impairment.

Troubleshooting the bypass: intraoperative management of initially failed anastomosis in direct cerebral revascularization surgery.

OBJECTIVE: Direct cerebral revascularization is considered as one of the most technically challenging operations in neurosurgery. Technical errors are often not identified during the case, but only after the recirculation stage, making management crucial at that time of the procedure. In this study, the authors sought to describe troubleshooting of the technical errors encountered in initially failed bypass cases. METHODS: A retrospective analysis describing a single-surgeon, single-institution experience between 2014 and 2021 was performed, based on operative reports and videos, including a 30-day follow-up period. Initially failed bypass was defined if the bypass was not patent or had a significant leak after recirculation, irrespective of the final result. RESULTS: One hundred thirty-eight bypass cases were reviewed for complex aneurysms (n = 49), moyamoya disease (n = 59), and atherosclerosis (n = 30). Fifty-one initially failed anastomoses were identified; 43 of these were the result of a technical error. Etiologies of these failed anastomoses included a clot (n = 14), vessel kinking (n = 4), spasm (n = 5), suture-related cause (n = 5), inappropriate donor or recipient (n = 3), or lack of demand (n = 8). A major leak was attributed to an uncoagulated side branch (n = 4), vessel injury due to suture/clip placement (n = 1), or inadequate suture line coverage (n = 7). Thirty-seven (86%) of 43 cases were troubleshot successfully, as salvage maneuvers included papaverine vessel massage, donor repositioning, re-anastomosis for occlusion in select cases, local hemostatic agents, and suturing or coagulating side branches in a leak. Thirty-day follow-up revealed similar rates of patency between successfully troubleshot patients (35/37) and the rest of the cases (80/87, p = 0.6). CONCLUSIONS: Three major patterns of a noncompatible bypass were found: a major leak, an acute occlusion, or a delayed occlusion. Based on the authors' experience, salvage strategies proved successful, showing an eventual high patency rate. The authors suggest a gradual, structured algorithm to address this stage in surgery that may contribute specifically to cerebrovascular neurosurgeons at the beginning of their careers.

Extracranial-Intracranial Bypass for Moyamoya Disease: The Influence of Racial and Socioeconomic Disparities on Outcomes - A National Inpatient Sample Analysis.

BACKGROUND: Extracranial-intracranial (EC-IC) bypass is an established therapeutic option for Moyamoya disease (MMD). However, little is known about the effects of racial and ethnic disparities on outcomes. This study assessed trends in EC-IC bypass outcomes among MMD patients stratified by race and ethnicity. METHODS: Utilizing the US National Inpatient Sample, we identified MMD patients undergoing EC-IC bypass between 2002 and 2020. Demographic and hospital-level data were collected. Multivariable analysis was conducted to identify independent factors associated with outcomes. Trend analysis was performed using piecewise joinpoint regression. RESULTS: Out of 14,062 patients with MMD, 1771 underwent EC-IC bypass. Of these, 60.59% were White, 17.56% were Black, 12.36% were Asians, 8.47% were Hispanic, and 1.02% were Native Americans. Nonhome discharge was noted in 21.7% of cases, with a 6.7% death and 3.8% postoperative neurologic complications rates. EC-IC bypass was more commonly performed in Native Americans (23.38%) and Asians (17.76%). Hispanics had the longest mean length of stay (8.4 days) and lower odds of nonhome discharge compared to Whites (odds ratio: 0.64; 95% confidence interval: 0.40-1.03; P = 0.04). Patients with Medicaid, private insurance, self-payers, and insurance paid by other governments had lower odds of nonhome discharge than those with Medicare. CONCLUSION: This study highlights racial and socioeconomic disparities in EC-IC bypass for patients with MMD. Despite these disparities, we did not find any significant difference in the quality of care. Addressing these disparities is essential for optimizing MMD outcomes.

Efficacy and Safety of Extracranial-Intracranial Bypass Surgery for Posterior Circulation Aneurysms: A Systematic Review and Single-Arm Meta-Analysis.

OBJECTIVE: Treating complex posterior circulation aneurysms poses challenges, and extracranial to intracranial (EC-IC) bypass techniques are potential therapeutic options. However, the safety and efficacy of this approach for posterior circulation aneurysms remain unclear. The study's objective was to assess the safety and efficacy of EC-IC bypass in these aneurysms. METHODS: Adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we conducted a systematic review on EC-IC revascularization for posterior circulation aneurysms. Included studies had at least 4 patients and reported data on mortality, patency, complications, or clinical outcomes. Favorable clinical outcomes were defined as modified Rankin Scale below 3 or Glasgow Outcome Scale above 3, and complications were any issues related to the bypass procedure. RESULTS: From 3036 articles reviewed, 22 studies involving 196 patients who underwent 210 EC-IC bypass procedures for posterior circulation aneurysms were selected. The median follow-up period of 14 studies was 31.66 months (6-61 months). Final follow-up indicated a high bypass patency rate of 96% [95% confidence interval [CI]: 91%-100%; I2 = 12%], with a mortality rate of 5% [95% CI: 1%-9%; I2 = 0%]. Additionally, 83% [95% CI: 70%-96%; I2 = 77%] of patients showed good outcomes at the last follow-up. Complications were observed in 40% [95% CI: 26%-55%; I2 = 80%]. Heterogeneity was associated with specific studies. CONCLUSIONS: EC-IC bypass procedures are a viable treatment option for posterior circulation aneurysms, with high bypass patency rates and favorable clinical outcomes. However, complications, especially neurological deficits, exist. Open revascularization remains essential for neurovascular surgeons dealing with complex aneurysms.

Proximal Internal Carotid Artery Occlusion and Extracranial-Intracranial Bypass for Treatment of Fusiform and Giant Internal Carotid Artery Aneurysms.

OBJECTIVE: To discuss the treatment of intracranial fusiform and giant internal carotid artery (ICA) aneurysms via revascularization based on our institutional experience. METHODS: An institutional review board-approved retrospective analysis was performed of patients with unruptured fusiform and giant intracranial ICA aneurysms treated from November 1991 to May 2020. All patients were evaluated for extracranial-intracranial (EC-IC) bypass and ICA occlusion. RESULTS: Thirty-eight patients were identified. Initially, patients failing preoperative balloon test occlusion were treated with superficial temporal artery (STA)-middle cerebral artery (MCA) bypass and concurrent proximal ICA ligation. We then treated them with STA-MCA bypass, followed by staged balloon test occlusion, and, if they passed, endovascular ICA coil occlusion. We treat all surgical medically uncomplicated patients with double-barrel STA-MCA bypass and concurrent proximal ICA ligation. The mean length of follow-up was 99 months. Symptom stability or improvement was noted in 85% of patients. Bypass graft patency was 92.1%, and all surviving patients had patent bypasses at their last angiogram. Aneurysm occlusion was complete in 90.9% of patients completing proximal ICA ligation. Three patients experienced ischemic complications and 4 patients experienced hemorrhagic complications. CONCLUSIONS: Not all fusiform intracranial ICA aneurysms require intervention, except when life-threatening rupture risk is high or symptomatic management is necessary to preserve function and quality of life. EC-IC bypass can augment the safety of proximal ICA occlusion. The rate of complete aneurysm occlusion with this treatment is 90.9%, and long-term bypass graft-related complications are rare. Perioperative stroke is a major risk, and continued evolution of treatment is required.

Comparison Between the Efficacy of a Flow Diverter and Interventional Trapping with Bypass in the Treatment of Unruptured Large- or Giant-Sized ICA Aneurysms.

OBJECTIVE: Management of large- or giant-sized internal carotid artery aneurysms (LICAAs) remains challenging. Whether a flow diverter device (FDD) or interventional trapping with extracranial-intracranial bypass (ITB) is better, remains unclear. METHODS: We conducted a multicenter retrospective analysis of unruptured LICAA patients treated with FDD or ITB at 3 medical centers. Both the effectiveness and safety results of FDD and ITB were compared. RESULTS: In total, 101 aneurysms in 95 patients treated with FDDs and 36 aneurysms in 36 patients managed with ITBs were included (September 2014-June 2021). There was no significant difference between the groups in the complete obliteration rate 1 year after surgery (P = 0.101). There were 2 relapse cases (2.0%) and 4 retreated cases (4.0%) in the FDD group and 1 relapse case (2.8%) and 2 retreated cases (5.6%) in the ITB group. Neither the relapse rates nor retreat rates between groups were significantly different. The neurological morbidity rates were 4.0% (4/101) and 2.8% (1/36) in the FDD group and ITB group, respectively, and were not significantly different. There was 1 mortality case in each group, and the mortality rates were not significantly different (P = 0.443). Both the perioperative and overall (perioperative plus long-term) complication rates in the FDD group were significantly lower than those in the ITB group (P = 0.033, P = 0.039). CONCLUSIONS: FDD had comparable surgical efficacy and a significantly lower postoperative complication rate to traditional ITB. FDD might be preferable to ITB as a treatment modality for LICAA.

Bilateral symptomatic large cavernous carotid artery aneurysms treated by extracranial-intracranial bypass with parent artery occlusion.

Bilateral large cavernous sinus internal carotid aneurysms (CCAs) occur very rarely. While the choice of treatment method is important, the timing of contralateral side treatment is equally important. We herein report the case of a 72-year-old woman who presented with progressive bilateral visual impairment and was treated by two-stage. First, the left CCAs had been treated, and the aneurysm was thrombosed, but her left visual acuity did not recover; the right CCA was becoming larger 2 years later, and her right visual acuity began worsening. The right CCAs was treated by almost same method. Her right visual acuity improved compared with the second preoperative findings. Our case findings suggest the importance of considering the appropriate timing to avoid symptom aggravation in patients with bilateral CCAs.

Extracranial-intracranial bypass surgery for intracranial aneurysm of the anterior cerebral circulation: A systematic review and meta-analysis.

Background: The safety of extracranial-intracranial (EC-IC) bypass in the management of anterior circulation intracranial aneurysms (IAs) remains to be determined. This systematic review aims to summarize the existing evidence and provide guidance for the precise management of IAs. Data source: We constructed search strategies and comprehensively searched Pubmed, Medline, Embase, Web of science, and Cochrane library. Methods: This systematic review was actualized according to the PRISMA statement. We evaluated study quality using the methodological index for non-randomized study (MINORS). Effect sizes were pooled using a random-effects model. Heterogeneity between studies was assessed using the I 2 test. Publication bias was assessed using the Egger's test. The registration number for this systematic review is CRD42023396730. Result: This systematic review included a total of 21 articles, involving 915 patients. Postoperative bypass patency rate was 99% (95% CI 0.98-1.00); short-term follow-up was 98% (95% CI 0.94-1.00); long-term follow-up was 95% (95% CI 0.93-0.97). The long-term follow-up occlusion rate of saphenous vein was higher than that of radial artery (OR 6.10 95% CI 1.04-35.59). Short-term surgery-related mortality was 0.3% (95% CI 0.000-0.012); long-term follow-up was 0.4% (95% CI 0.000-0.013); The proportion of patients with a score of 0-2 on the modified Rankin Scale (mRS) during long-term follow-up was 92% (95% CI 0.86-0.98). The incidence rates of long-term follow-up complications were: ischemic 3% (95% CI 0.01-0.06); hemorrhagic 1% (95% CI 0.00-0.03); neurological deficit 1% (95% CI 0.00-0.03); other 3% (95% CI 0.01-0.06). Limitation: Most of the included studies were retrospective studies. Studies reporting preoperative status were not sufficient to demonstrate postoperative improvement. Lack of sufficient subgroup information such as aneurysm rupture status. Conclusion: EC-IC therapy for anterior circulation IAs has a high safety profile. Higher level of evidence is still needed to support clinical decision. Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023396730, identifier: CRD42023396730.

Maxillary Nerve as Landmark for Exposure of the Internal Maxillary Artery in Extracranial-Intracranial Bypass Surgery.

OBJECTIVE: To establish a new method for fast exposure of the internal maxillary artery (IMA) during extracranial-intracranial bypass surgery. METHODS: To explore the positional relationship between the IMA and the maxillary nerve and pterygomaxillary fissure, 11 formalin-fixed cadaveric specimens were dissected. Three bone windows of the middle fossa were created for further analysis. Then the IMA length that could be pulled up above the middle fossa was measured after different degrees of removal of bony structure. The IMA branches under each bone window were also explored in detail. RESULTS: The top of the pterygomaxillary fissure was located 11.50 mm anterolateral to the foramen rotundum. The IMA could be identified just inferior to the infratemporal segment maxillary nerve in all specimens. After drilling of the first bone window, the IMA length that could be pulled above the middle fossa bone was 6.85 mm. After drilling of the second bone window and further mobilization, the IMA length that could be harvested was significantly longer (9.04 mm vs. 6.85 mm; P < 0.001). Removal of the third bone window did not significantly improve the IMA length that could be harvested. CONCLUSIONS: The maxillary nerve could be used as a reliable landmark for the exposure of the IMA in the pterygopalatine fossa. With our technique, the IMA could be easily exposed and sufficiently dissected without zygomatic osteotomy and extensive middle fossa floor removal.

Understanding the difference between theory and practice: The extracranial-intracranial bypass trials in prevention of ischemic stroke.

BACKGROUND: Patients with atherosclerotic carotid or middle cerebral artery occlusions suffer ischemic events that might theoretically be preventable with a surgical extracranial-intracranial bypass, but theory by itself does not justify surgical interventions. METHODS: We review landmark randomized trials on EC-IC bypass surgery for the treatment of ischemic stroke in patients with atherosclerotic stenoses or occlusions. RESULTS: The initial EC-IC bypass trial from 1985 did not show any clinical benefit from surgery. The carotid occlusion surgery study (COSS) performed more than 20 years later included only patients highly selected to potentially benefit from bypass by using modern perfusion studies. While EC-IC bypasses were successfully created and they did improve cerebral perfusion, the COSS study also failed to show any clinical benefit to the participating patients. CONCLUSION: Neurosurgical interventions must not only work in theory; they must improve patient outcomes in real practice.

Understanding how the primary endpoint impacts the interpretation of trial results: The Japanese Adult Moyamoya bypass trial.

BACKGROUND: The meaning of a clinical trial depends to a large extent on the choice of the primary outcome measure, which can be explanatory or pragmatic. METHODS: We review the Japanese Adult Moyamoya (JAM) trial, that compared surgical extracranial to intracranial (EC-IC) bypass and medical management of hemorrhagic moyamoya disease. We also review some principles which guide the selection of the primary trial endpoint. DISCUSSION: The main component of the primary outcome measure in JAM was rebleeding, a surrogate outcome that allowed investigators to demonstrate that surgical bypass had causal efficacy. However, the number of patients with a poor outcome, defined as those with a modified Rankin score (mRS)>2, would have been a more pragmatic choice. Unfortunately, the trial was too small to show that patients benefited from surgery. CONCLUSION: The JAM trial showed that EC-IC bypass can decrease rebleeding in moyamoya patients, but whether patients have better outcomes with surgery remains uncertain. Hard pragmatic clinical primary outcome measures are necessary to guide surgical care.

Extracranial-intracranial bypass in a neonate with multiple ruptured middle cerebral artery aneurysms: illustrative case.

BACKGROUND: Reports of ruptured neonatal aneurysms are rare in neurosurgical literature. Pediatric aneurysms differ from adult aneurysms, notably in morphology, size, number, and risk of rerupture. Many authors report experience with clipping, citing durability and decreased use of radiation as benefits over endovascular intervention. Few authors report extracranial-to-intracranial bypass because small pediatric vessels make this option challenging. The authors discussed a case of a newborn with multiple ruptured aneurysms, one of the youngest reported cases involving extracranial-intracranial bypass. OBSERVATIONS: A 3-week-old baby presented with hemorrhage from multiple complex middle cerebral artery (MCA) aneurysms. Because of young age, endovascular intervention was not possible; therefore, the patient received craniotomy. Upon exploration, clip reconstruction was impossible; the vessel was trapped, and superficial temporal artery (STA)-MCA bypass was performed. The recipient vessel diameter was 0.3 mm. The postoperative course was complicated by seizures as well as symptomatic vasospasm, which was treated with intraarterial verapamil and ventriculostomy. At last follow-up, the patient was developing normally and was ambulatory with minimal deficit. LESSONS: This case, one of the youngest patients reported, highlighted details of pediatric aneurysm management, such as propensity for multiple/fusiform aneurysms and high risk of re-hemorrhage, with significant mortality. The authors recommended aggressive, early intervention in pediatric aneurysms at centers with surgeons familiar with both endovascular intervention and cerebral bypass.

Flow alteration therapy for impending rupture of intracranial giant aneurysm after flow diverter placement.

Background: Flow diverter (FD) placement is generally effective for intractable internal carotid artery (ICA) aneurysms. However, salvage treatment for the aneurysm enlarging even after FD placement remains to be elucidated. Additional overlapping FD placement is considered the first-line treatment for residual or recurrent aneurysms. However, it is unclear whether overlapping FD is also effective for enlarging giant aneurysms that are considered impending rupture status. Although parent artery occlusion is a promising option, treatment strategy must be optimized, especially when a critical perforating artery is involved. Case Description: A 74-year-old woman experienced rapid symptomatic growth of her giant supraclinoid ICA aneurysm 10 months after FD placement. We assumed that reinforcement of flow diverting effect alone would be less effective for this extremely intractable aneurysm with more aggressive clinical feature so that surgical bailout by parent artery occlusion was planned. Complete ICA obliteration underneath the aneurysm was unavailable due to the presence of anterior choroidal artery. Thus, we took a flow alteration strategy, where we created minimal retrograde flow through the parent artery by a combination of an extracranial-intracranial bypass and targeted endovascular proximal parent artery obliteration, resulting in prevention of aneurysmal rupture and further growth. Conclusion: Impending rupture of the intracranial giant aneurysm after FD placement may be controllable with a tailor-made parent artery occlusion strategy even when a critical perforating artery is involved.

Characteristics and outcomes of stroke hospitalizations in patients with sickle cell disease and moyamoya syndrome.

OBJECTIVES: Stroke is the leading cause of death in patients with Sickle cell disease (SCD). Here, we detail the burden of Moyamoya syndrome (MMS) as a cause of stroke in patients with SCD. MATERIALS AND METHODS: A review of SCD-related hospital discharges was conducted utilizing the National Inpatient Sample. Rates of stroke hospitalization, risk factors, procedures, and outcomes were compared between patients with SCD-MMS and SCD alone. Univariate analyses including T-test, Wilcoxon Rank-Sum test, Chi-square were performed to compare risk factors and outcomes. Multivariable regression was used to identify predictors of stroke unique to each population. RESULTS: Stroke occurred in 9.8% of SCD-MMS hospitalizations versus 0.5% of those involving patients with SCD alone (OR = 20.71, p < 0.001). Patients with SCD-MMS developed stroke at younger ages and with fewer comorbidities compared to those with SCD alone. Stroke hospitalizations in SCD-MMS involved a greater number of procedures (90.5% vs. 79.3%, p = 0.007), but were more likely to result in favorable discharge (58.5% vs. 44.2%, p = 0.005). The presence of anemia during hospitalization was a significant risk factor for stroke in both cohorts. Long-term antiplatelet use was protective against stroke (OR = 0.42, p = 0.008) only in the SCD-MMS cohort. CONCLUSIONS: MMS confers a 20-fold increased risk of stroke among patients with SCD and appears to be an important cause of recurrent stroke in this population. Anemia is one of the most significant risk factors for stroke, while antiplatelet use appears to confer a protective benefit.

Maximal Resection of Tumors Encasing the Internal Carotid Artery and Hindering Internal Carotid Artery Expansion Followed by Revascularization Surgery: A Series of Nine Cases at a Single Tertiary Center.

PURPOSE: Cerebral reconstruction appears to play a diminished role in managing complex skull base tumors involving vital neurovascular structures. MATERIALS AND METHODS: Patients with recurrent or progressive middle cranial fossa tumors treated by radical resection followed by extracranial-to-intracranial (EC-IC) bypass from 2014 to 2019 were included. Balloon test occlusion (BTO) was performed preoperatively. RESULTS: Overall, 9 patients (5 males, 4 females; mean age, 29.9 years) were enrolled. The lesions arose from the parasellar region (3), cavernous sinus (3), petroclival region (2), or orbital apex (1), and all encased the cavernous/petrous portion of the internal carotid artery. Before tumor resection, internal maxillary artery (IMA) bypass was performed for 7 patients, cervical EC-IC bypass was performed for 1 patient, and interposed superficial temporal artery (STA) bypass was performed for 1 patient. BTO failed in 8 patients and was tolerated by one patient. Intraoperative blood flow of the interposed graft was 79.7 ± 37.86 ml/min after IMA bypass, 190.6 ml/min following cervical EC-IC bypass and 75 ml/min after interposed STA bypass. All bypasses were patent on intraoperative indocyanine green angiography. Radical tumor resection was achieved in 5 patients (55.6%), and patency was confirmed postoperatively in 88.8% (8/9) of bypasses. Six patients showed favorable outcomes at discharge. At the 2-year follow-up, 7 patients (77.8%) had favorable outcomes (Karnofsky Performance Scale score>80). At the 1.5-year follow-up, one patient had died due to infarction; at the 3-year follow-up, another patient had developed tumor recurrence despite being asymptomatic. CONCLUSION: Cerebral bypass remains a vital tool for managing select middle cranial fossa tumors that invade or erode the surrounding neurovasculature or hinder carotid artery expansion and are difficult to resect.

Giant Aneurysm Management.

The treatment of giant aneurysms has always been a challenge in the field of neurovascular disease. Giant aneurysms are larger in size and are associated with thrombosis development and the calcification of the aneurysmal wall and neck, which often interfere with direct clipping. Most giant aneurysms have a wide neck with an incomplete thrombus, making complete embolization almost impossible. Giant aneurysms of different sites have entirely different hemodynamic characteristics. Moreover, aneurysms at the same site may exhibit very different hemodynamics among different individuals. Therefore, careful assessment of each case is required before and during treatment to develop and carry out an individualized treatment plan.

Increased cerebrovascular reactivity in selected brain regions after extracranial-intracranial bypass improves the speed and accuracy of visual cancellation in patients with severe steno-occlusive disease: a preliminary study.

The effect of the change in cerebrovascular reactivity (CVR) in each brain area on cognitive function after extracranial-intracranial bypass (EC-IC bypass) was examined. Eighteen patients who underwent EC-IC bypass for severe unilateral steno-occlusive disease were included. Single-photon emission CT (SPECT) for evaluating CVR and the visual cancellation (VC) task were performed before and after surgery. The accuracy of VC was expressed by the arithmetic mean of the age-matched correct answer rate and the accurate answer rate, and the averages of the time (time score) and accuracy (accuracy score) of the four VC subtests were used. The speed of VC tended to be slower, whereas accuracy was maintained before surgery. The EC-IC bypass improved CVR mainly in the cerebral hemisphere on the surgical side. On bivariate analysis, when CVR increased post-operatively, accuracy improved on both surgical sides, but the time score was faster on the left and slower on the right surgical side. Stepwise multiple regression analysis showed that the number of the brain regions associated with the time score was 5 and that associated with the accuracy score was 4. In the hemodynamically ischemic brain, processing speed might be adjusted so that accuracy would be maintained based on the speed-accuracy trade-off mechanism that may become engaged separately in the left and right cerebral hemispheres when performing VC. When considering the treatment for hemodynamic ischemia, the relationship between CVR change and the speed-accuracy trade-off in each brain region should be considered.