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BACKGROUND: Surgical revascularization decreases the long-term risk of stroke in children with moyamoya arteriopathy but can be associated with an increased risk of stroke during the perioperative period. Evidence-based approaches to optimize perioperative management are limited and practice varies widely. Using a modified Delphi process, we sought to establish expert consensus on key components of the perioperative care of children with moyamoya undergoing indirect revascularization surgery and identify areas of equipoise to define future research priorities. METHODS: Thirty neurologists, neurosurgeons, and intensivists practicing in North America with expertise in the management of pediatric moyamoya were invited to participate in a three-round, modified Delphi process consisting of a 138-item practice patterns survey, anonymous electronic evaluation of 88 consensus statements on a 5-point Likert scale, and a virtual group meeting during which statements were discussed, revised, and reassessed. Consensus was defined as ≥ 80% agreement or disagreement. RESULTS: Thirty-nine statements regarding perioperative pediatric moyamoya care for indirect revascularization surgery reached consensus. Salient areas of consensus included the following: (1) children at a high risk for stroke and those with sickle cell disease should be preadmitted prior to indirect revascularization; (2) intravenous isotonic fluids should be administered in all patients for at least 4 h before and 24 h after surgery; (3) aspirin should not be discontinued in the immediate preoperative and postoperative periods; (4) arterial lines for blood pressure monitoring should be continued for at least 24 h after surgery and until active interventions to achieve blood pressure goals are not needed; (5) postoperative care should include hourly vital signs for at least 24 h, hourly neurologic assessments for at least 12 h, adequate pain control, maintaining normoxia and normothermia, and avoiding hypotension; and (6) intravenous fluid bolus administration should be considered the first-line intervention for new focal neurologic deficits following indirect revascularization surgery. CONCLUSIONS: In the absence of data supporting specific care practices before and after indirect revascularization surgery in children with moyamoya, this Delphi process defined areas of consensus among neurosurgeons, neurologists, and intensivists with moyamoya expertise. Research priorities identified include determining the role of continuous electroencephalography in postoperative moyamoya care, optimal perioperative blood pressure and hemoglobin targets, and the role of supplemental oxygen for treatment of suspected postoperative ischemia.

The effects of RNF213, which leads to moyamoya disease susceptibility, on radiation-induced moyamoya syndrome (MMS) remain unknown. We report a case of MMS after proton beam therapy (PBT) was deployed to treat a brain tumor in a patient with an RNF213 polymorphism. An 8-year-old boy underwent whole ventricular and local PBT for a pineal germ cell tumor and was diagnosed with radiation-induced MMS 9 months later. He underwent right and left revascularization surgeries for cerebral hemodynamic compromise at 17- and 18-years of age, respectively. Genetic analysis revealed a heterozygous germline polymorphism RNF213 p.R4810K. This is the first report to suggest an association between RNF213 polymorphism and radiation-induced MMS. [ABSTRACT FROM AUTHOR]

The study is devoted to the hemodynamics during cerebral vascular bypass surgery for the treatment of cerebral aneurysms in two patients. The location, morphological characteristics and treatment approaches of the patients were similar, but different outcomes were observed as a result of the performed microsurgical procedures. Computational approach was used to analyze the hemodynamic differences of aneurysms, treated via extra-intra cranial (EC-IC) cerebral bypass shunt. The paper presents a new criterion based on the energy parameters of healthy compartment of cerebral circulation. The applied approach demonstrates a new effective method of preoperative risk modelling for medical decision-making. [ABSTRACT FROM AUTHOR]

Cerebral hyperperfusion syndrome (CHS) is a serious complication after bypass surgery in Moyamoya disease (MMD), with autoregulatory dysfunction being a major pathogenesis. This study investigated the change of perioperative autoregulation and preoperative prognostic potentials in MMD with postoperative CHS. Among 26 hemispheres in 24 patients with adult MMD undergoing combined bypass, 13 hemispheres experienced postoperative CHS. Arterial blood pressure and cerebral blood flow velocity were perioperatively measured with transcranial Doppler ultrasound during resting and the Valsalva maneuver (VM). Autoregulation profiles were discovered in both the CHS and non-CHS groups using mean flow index (Mxa), VM Autoregulatory Index (VMAI), and a new metric termed VM Overshooting Index (VMOI). The CHS group had inferior autoregulation than the non-CHS group as indicated by VMOI on preoperative day 1 and postoperative 3rd day. Deteriorated autoregulation was observed via Mxa in the CHS group than in the non-CHS group on the postoperative 3rd and discharge days. Postoperative longitudinal autoregulation recovery in the CHS group was found in a logistic regression model with diminished group differences over the time course. This work represents a step forward in utilizing autoregulation indices derived from physiological signals, to predict the postoperative CHS in adult MMD. [ABSTRACT FROM AUTHOR]

Cerebral revascularization for the treatment of atherosclerotic steno-occlusive disease (ASOD) was found to have no benefit compared with medical treatment. However, there is also criticism that with sufficiently long-term follow-up, a crossover might emerge demonstrating the advantages of surgery. Therefore, we examined the long-term outcome of cerebral revascularization performed on patients with carefully selected ASOD at our center. Patients undergoing bypass surgery for non-moyamoya ischemic disease were retrospectively identified. The inclusion criteria were symptomatic ASOD with hemodynamic insufficiency, follow-up of more than 5 years, and stroke or surgical complications during follow-up. The clinical course and radiological findings were investigated. Poor outcomes were predicted using machine learning (ML) models, and Shapley additive explanation (SHAP) values and feature importance of each model were analyzed. A total of 109 patients were included from 2007 to 2018. The 30-day risk of any stroke or death was 6.4% (7/109). The risk of ipsilateral ischemic stroke during median follow-up of 116 months was 7.3% (8/109). The SHAP values showed that previously and empirically known stroke risk factors exert a relatively consistent effect on the prediction of models. The number of lesions with stenosis > 50% (odds ratio [OR] 5.77), age (OR 1.13), and coronary artery disease (OR 5.73) were consistent risk factors for poor outcome. We demonstrated an acceptable long-term outcome of cerebral revascularization surgery for patients with hemodynamically insufficient and symptomatic ASOD. Multicenter studies are encouraged to predict poor outcomes and suitable patients with large numbers of quantitative and qualitative data. [ABSTRACT FROM AUTHOR]

Purpose: This technical note introduces the novel faucet technique, which enables neurosurgeons to evaluate the patency of a bypass during superficial temporal artery–middle cerebral artery bypass surgery. The technique is particularly useful when there is a lack of equipment such as micro-Doppler or indocyanine green in the operating rooms. This is often the case in Central Asian countries. Methods: The faucet technique involves carefully examining the graft by gently opening a valve, comparable to a faucet, to observe the blood flow through the bypassed vessel. Overall, 36 procedures underwent the faucet technique for assessing the superficial temporal artery–middle cerebral artery bypass patency. Results: The results indicate that the bypass remained patent in all cases, as confirmed through the intraoperative faucet technique, postoperative magnetic resonance angiography, or cerebral angiography. Conclusion: By visually inspecting the blood flow through the faucet technique, surgeons can confirm the effectiveness of the graft and ensure that the bypass remains unobstructed during the surgery. [ABSTRACT FROM AUTHOR]

To create a reusable and inexpensive training model with technological tools that simulates cerebral bypass surgery and a sensor system that provides tactile feedback to the surgeon. Furthermore, we aimed to evaluate the anastomotic stability and contribution to the surgeon's learning curve. We created a superficial temporal artery–middle cerebral artery bypass simulation model using chicken and turkey brachial arteries. A cranium model was printed with a three-dimensional printer for craniotomy and cerebral parenchyma was created by pouring silicone into the cranial mold. A blood flow simulation system was also prepared. Pressure-sensitive sensors were placed on parenchyma and tactile conditioning was performed via audible warning from the sensors. Twenty-four anastomosis were performed with different sutures and hand tools. Anastomosis completion times and durability and the number of touches and pressures applied to the parenchyma were recorded. The stability of the anastomoses was evaluated by increasing the pressure in the blood flow simulation system, so usefulness of the training model was evaluated. The time required for anastomosis completion decreased as the number of practices increased (P < 0.05). As the number of practices increased, the number of parenchymal touches decreased (P < 0.05). With practice, the time required for anastomosis completion and number of parenchymal touches decreased. Thus, the model is useful, inexpensive, reusable, easily accessible, and contributes to the surgeon's learning curve. Our model with pressure-sensitive sensors can be used for microsurgery practice, enabling the surgeons to gain tactile conditioning and evaluate anastomotic stability and leakage. [ABSTRACT FROM AUTHOR]

Background: Systemic immune-inflammatory markers combine various individual inflammatory cell parameters to comprehensively explore their relationship with the development and long-term outcomes of cardiovascular, cerebrovascular, and oncological disorders. The systemic immune-inflammatory marker index has not been extensively studied in terms of its impact on the long-term prognosis following cerebral revascularization in MMD patients. Our research aims to address this gap and improve the prediction of long-term outcomes for these patients. Methods: We included 851 patients with Moyamoya disease who underwent cerebral revascularization at our medical center from 2009 to 2021. Systemic immune-inflammatory markers were calculated based on routine blood test results at admission, and follow-up was conducted for over 6 months after surgery. During monitoring and upon release, we evaluated patient neurological condition by utilizing the modified Rankin Scale (mRS). We examined the correlation between alterations in mRS ratings and systemic immuneinflammatory markers. Results: Comparing the unfavorable long-term prognosis group to the favorable long-term prognosis group, it was found that the NLR level was markedly higher (p = 0.037), while the LMR was lower in the unfavorable long-term prognosis group (p = 0.004). Results from logistic regression analysis revealed that the high-level LMR group had a lower risk of unfavorable long-term prognosis compared to the low-level group (T3: OR = 0.433, 95% CI [0.204-0.859], p = 0.026). The AUC of the model was 0.750 (95% CI [0.693-0.806]). Conclusion: Lymphocyte-to-monocyte ratio levels are independently linked to an increased risk of unfavorable long-term prognosis, highlighting LMR as a new and effective predictor for postoperative Moyamoya patients. [ABSTRACT FROM AUTHOR]

Training in anastomosis is fundamental in neurosurgery due to the precision and dexterity required. Biological models, although realistic, present limitations such as availability, ethical concerns, and the risk of biological contamination. Synthetic models, on the other hand, offer durability and standardized conditions, although they sometimes lack anatomical realism. This study aims to evaluate and compare the efficiency of anastomosis training models in the intra-extracranial cerebral bypass procedure, identifying those characteristics that enhance optimal microsurgical skill development and participant experience. A neurosurgery workshop was held from March 2024 to June 2024 with 5 vascular techniques and the participation of 22 surgeons. The models tested were the human placenta, the Wistar rat, the chicken wing artery, the nasogastric feeding tube, and the UpSurgeOn Mycro simulator. The scales used to measure these models were the Main Characteristics Score and the Evaluation Score. These scores allowed us to measure, qualitatively and quantitatively, durability, anatomical similarity, variety of simulation scenarios, risk of biological contamination, ethical considerations and disadvantages with specific infrastructure. The human placenta model, Wistar rat model, and UpSurgeOn model were identified as the most effective for training. The human placenta and Wistar rat models were highly regarded for anatomical realism, while the UpSurgeOn model excelled in durability and advanced simulation scenarios. Ethical and cost implications were also considered. The study identifies the human placenta and UpSurgeOn models as optimal for training in intra-extracranial bypass procedures, emphasizing the need for diverse and effective training models in neurosurgery. [ABSTRACT FROM AUTHOR]

Microanastomosis presents a challenge in neurosurgical procedures, requiring specialized skills. Regular practice outside the operating room is crucial. This study aims to provide a detailed description of the side-to-side anastomosis technique and analyze its advantages in preventing failures compared with other variations. We examined the technique, characteristics, and outcomes of side-to-side bypass procedures for complex aneurysms in the anterior cerebral artery territory at our institution over the past decade. We compared our technique with those described in the literature by other groups. The Far East Neurosurgical Institute (FENI) technique was used in 15 patients, with 17 side-to-side anastomoses performed. The average anastomosis time was 27.5 minutes, with 100% patency in follow-up. Our technique demonstrated safety and effectiveness in treating intracranial aneurysms, yielding satisfactory short- and long-term functionality outcomes. We highlight the importance of maintaining a curvilinear arteriotomy shape, at least 3 times the diameter of the artery, and utilizing an interrupted suturing technique on the anterior wall. This paper presents the first comprehensive description of the side-to-side anastomosis technique, supported with images and videos for training and replicability. Our technique enhances flow dynamics and reduces the risk of acute thrombus formation. Training in simulators and microsurgery practice centers outside the operating room is essential for acquiring and refining microsurgical skills. [ABSTRACT FROM AUTHOR]

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Recent cohort studies on hemorrhagic and asymptomatic moyamoya disease have revealed that choroidal anastomosis, a type of fragile periventricular collateral pathway (periventricular anastomosis) typical of the disease, is an independent predictor of hemorrhagic stroke. However, treatment strategies for less-symptomatic nonhemorrhagic patients with choroidal anastomosis remain unclear. The Moyamoya Periventricular Choroidal Collateral (P-ChoC) Registry is an ongoing multicentered observational study that will test the hypothesis that extracranial-intracranial bypass prevents de novo hemorrhagic stroke in less symptomatic, nonhemorrhagic patients with choroidal anastomosis and may thus contribute to improving the prognosis of moyamoya disease. In this study, we report the study protocol of the moyamoya P-ChoC Registry and review the literature on choroidal anastomosis as a fragile collateral pathway.

Objective To explore the efficacy and advantages of intracranial-intracranial bypass for the treatment of complex intracranial aneurysms. Methods A total of 9 patients with complex intracranial aneurysms who underwent intracranial-intracranial bypass in Xiangya Hospital of Central South University from February 2014 to May 2020 were included, and were treated with grafts bypass or reimplantation of recipient arteries. All cases underwent CTA or DSA to detect the patent of grafts, whether aneurysms were completely clipped or resected and aneurysms recurrence occurred during the follow-up. Modified Rankin Scale (mRS) was used to evaluate the neurological prognosis at discharge and during the follow - up. Results Radial artery (RA) or great saphenous vein (GSV) was used for interposition in 4 cases, and recipient arteries were used for reimplantation in 5 cases. Of 4 cases of interposition, the cavernous sinus seoment of internal carotid artery (ICA)-GSV-ICA bypass was adopted in one case, middle cerebral artery (MCA) M2-RA-M2 bypass in one case, anterior cerebral artery (ACA) A3-GSV-A3 bypass in one case, posterior cerebral artery (PCA) P2 -RA -P2 bypass in one case. Of 5 cases of reimplantation, MCA M2 inferior trunk was reimplanted to M2 superior trunk in one case, ACA A3 was reimplanted to contralateral A3 in 2 cases, the posterior inferior cerebellar artery (PICA) was reimplanted to the anterior inferior cerebellar artery (AICA) in 2 cases. CTA in 3 d postoperatively showed all cases grafts were patent and aneurysms disappeared. After 3 months of discharge, 2 were lost to follow-up. The other 7 cases kept the patency of grafts and no new aneurysms, and were constantly followed up, with an average follow-up time of 30.71 months, and mRS score was 1 or lower. Conclusions Intracranial - intracranial bypass can be applied for complex intracranial aneurysms that are difficult for conventional surgical treatment to solve. Compared with extracranial - intracranial bypass, its grafts are shorter and its hemodynamics features are more in line with physiological conditions.

Cerebral revascularization is constantly being updated and iterated, but there are still many challenges: how to regulate the bypass flow quantitatively, how to reconstruct cerebral artery perforator vessels with diameter less than 0.5 mm, etc.. This paper reviews the birth of revascularization and the development of cerebral revascularization, focusing on the basic principle and innovative technology of cerebral revascularization, application and effect of cerebral revascularization in the treatment of complex intracranial aneurysms, current situation and development trend of cerebral revascularization iteration. The aim is to promote the iteration of cerebral revascularization and its application in the treatment of complex intracranial aneurysms.

Cerebral vascular bypass is a key method for the treatment of complex intracranial aneurysms. After nearly 60 years of exploration, its application range now covers the whole cerebral vascular region. With the advent of detachable coils and the mature application of related assistance techniques, endovascular intervention treatment is highly favored in the treatment of routine intracranial aneurysms due to its minimally invasive and rapid characteristics. The introduction of flow diverter (FD) has further ushered in a new era in the treatment of intracranial aneurysms. This article reviews the history and development of cerebral vascular bypass in the treatment of intracranial aneurysms, elaborates on the application and promotion of flow diverter, and discusses the limitations of endovascular intervention treatment in the flow diversion era. It also explores the application and prospects of a comprehensive cerebral vascular bypass system, reaffirming the application value of the whole - region cerebral vascular bypass technique.

Objective To explore the surgical procedures and indications of intracranial - intracranial bypass for the treatment of complex aneurysms in the basilar artery (BA). Methods and Results A retrospective analysis was conducted on the clinical data and treatment process of 6 patients with complex BA aneurysms who underwent intracranial-intracranial bypass from April 2017 to April 2023 in Tianjin Huanhu Hospital. Among the 6 aneurysms, 3 were vertebro basilar dolichoectasia aneurysms, one was an aneurysm in the upper segment of BA combined with severe stenosis at the proximal of the aneurysm, and 2 were giant dissecting aneurysms of the BA. Among them, 5 were ruptured aneurysms, with one case of Hunt-Hess grade Ⅴ, one case of grade Ⅳ, 2 cases of grade Ⅲ, and one case of grade Ⅱ, while the remaining one case was an unruptured aneurysm. One patient underwent petrous segment of internal carotid artery (ICA) - radial artery (RA) - posterior cerebral artery (PCA) bypass combined with aneurysm clipping, 4 patients underwent V3 segment of vertebral artery (VA) - RA - PCA bypass combined with aneurysm trapping, and one patient underwent middle cerebral artery (MCA)-RA-PCA bypass combined with aneurysm trapping. Four patients had good prognosis, with modified Rankin Scale (mRS) 0 to 3, one case scored 4 and one case died one week after surgery. Conclusions For complex aneurysms of the BA that cannot be treated with conventional methods, intracranial-intracranial bypass provides a good option. It is necessary to select the appropriate surgical procedure based on the actual situation in clinical practice.

Objective To explore the long-term outcome of intracranial-intracranial side-to-side bypass for complex intracranial aneurysms. Methods Five patients with complex intracranial aneurysms underwent intracranial-intracranial side-to-side bypass performed by the same surgeon at The First Hospital of China Medical University from January 2015 to December 2023 were included. Two cases involved the A2 segment of anterior cerebral artery (ACA) and 3 cases involved the M2 segment of middle cerebral artery (MCA). Indocyanine green angiography (ICGA) was used intraoperatively, and CTA or DSA was used postoperatively to evaluate aneurysm occlusion and blood flow reconstruction. The modified Rankin Scale (mRS) was used to evaluate the neurological prognosis at one week, 3 months and the last follow-up. CT/ MRI examination was completed on the first day, one week and 3 months after operation to evaluate whether hemorrhagic or ischemic complications occurred. Results Five cases of complex intracranial aneurysms were all occluded accurately. Two cases underwent A3-A3 side-to-side anastomosis, and 3 cases underwent M2-M2 side-to-side anastomosis, among which one case added M1-radial artery (RA)-M2 intracranialintracranial bypass with RA as graft on the basis of M2-M2 side-to-side anastomosis. During the operation, ICGA confirmed that the side-to-side anastomosis and M1-RA-M2 bypass were unobstructed in 5 cases. The postoperative follow - up time was 23 (14, 71) months. No aneurysm was found in cerebrovascular imaging examination one week and 3 months after operation in 5 patients, and 9 to 12 months after operation in 3 patients. Five side - to - side anastomosis stomas and one M1 - RA - M2 graft were all unobstructed. At one week after operation, the mRS increased by 0-3 score compared with that before operation (4 score maintained unchanged before and after operation in one case, 2 score increased in one case, and 3 score increased in one case). In 2 unruptured cases, the mRS score was 1 score at one week after operation, and there was no change from that before operation. At 3 months after operation, the mRS scores of 5 cases were decreased (2 cases with 0 score, one case with 2 score, and 2 cases with 3 score); one case was lost at the last follow-up, and the mRS scores of other 4 cases decreased further (2 cases with 0 score, one case with 1 score, and one case with 2 score). No cerebral hemorrhage or cerebral ischemia occurred in the follow-up. Conclusions Intracranial-intracranial side-to-side bypass has good short-term and long-term patency and stable long-term clinical effect. It is a reliable technique for surgical treatment of complex intracranial aneurysms.

Intracranial-intracranial bypass is a crucial treatment for complex intracranial aneurysms, as it not only achieves aneurysm eradication but also ensures perfusion to the bypassed vascular territory. To ensure bypass vessels patency and postoperative neurological recovery in patients with aneurysm, it is necessary to consider multiple characteristics of the aneurysm, donor artery and recipient artery. This comprehensive evaluation enables the selection of appropriate surgical decisions and bypass techniques. In recent years, with the advancement of intracranial-intracranial bypass, several new options including donor artery and recipient artery, anastomosis techniques, graft vessels, and auxiliary techniques have been added for neurosurgeons to choose from. This review aims to introduce the technical advances, surgical experience of intracranial - intracranial bypass for complex intracranial aneurysms, with the intention of facilitating clinical application of intracranial-intracranial bypass.

Objective To explore the efficacy and safety of intracranial-intracranial bypass for the treatment of complex intracranial aneurysms. Methods and Results A total of 32 patients with complex intracranial aneurysms who were hospitalized for treatment at Huashan Hospital, Fudan University from January 2015 to December 2023 were included. Surgical methods included in-situ bypass, reimplantation, reanastomosis and bypass with interposition graft. For middle cerebral artery (MCA) aneurysms (n = 16), there were 5 cases of in-situ bypass, one case of reimplantation, 3 cases of reanastomosis, and 7 cases of bypass with interposition graft. For anterior cerebral artery (ACA) aneurysms (n = 8), there were 5 cases of in-situ bypass and 3 cases of reimplantation. For anterior communicating artery (ACoA) aneurysms (n = 2), both cases were in-situ bypass. For posterior circulation aneurysms (n = 6), there were 3 cases of in-situ bypass, 2 cases of reanastomosis, and one case of bypass with interposition graft. The intraoperative graft vessels patency rate was 100%. Among the 23 patients who participated in follow-up imaging for more than 6 months postoperatively, no obvious recurrence was indicated by imaging. Among the 28 patients who participated in modified Rankin Scale (mRS) follow-up, there was one case of 5, 5 cases of 3, 2 cases of 2, one case of 1, and 19 cases of 0. Postoperative hemorrhagic complications occurred in 3 cases (9.37%), and ischemic complications occurred in 10 cases (31.25%), with no patients requiring unplanned secondary surgery for complication treatment. Conclusions Intracranial-intracranial bypass has good efficacy and safety for the treatment of complex intracranial aneurysms and has unique advantages in the microsurgical treatment of complex intracranial aneurysms.

The iteration of cerebral revascularization has been accompanied by the evolution of the concept of complex intracranial aneurysms. Cerebral revascularization has gradually changed the treatment strategy of intracranial aneurysms. This article focuses on the treatment principles and common microsurgical techniques of intracranial aneurysms, the conceptual changes and treatment difficulties of complex intracranial aneurysms, the development trend of cerebral revascularization and its application in the treatment of complex intracranial aneurysms, and the prospect of cerebral revascularization in the treatment of complex intracranial aneurysms. It aims to promote the high-quality application of cerebral revascularization in the treatment of intracranial aneurysms.

Background Complex intracranial aneurysms are one of the most difficult cerebrovascular diseases to treat, and even experienced cerebrovascular surgeons face great challenges. Intracranial - intracranial bypass with interposition graft has its unique surgical indications and technical points, but there is a lack of research reports in the literature at home and abroad. Methods Six patients with complex intracranial aneurysms who were cured by intracranial-intracranial bypass with interposition graft from January 2015 to December 2023 in The First Medical Center of PLA General Hospital were enrolled, DSA was used to evaluate the patency of postoperative grafts and aneurysm development, modified Rankin Scale (mRS) was used to evaluate the neurological prognosis, and the procedure - related complications such as cerebral infarction, intracranial hemorrhage, scalp nonunion, and forearm nerve dysfunction were recorded. Results All 6 patients successfully completed intracranial-intracranial bypass with interposition graft, with superficial temporal artery (STA) in 5 cases and radial artery (RA) in one case. The grafts were embedded between the proximal and distal parent arteries in 2 cases, and the grafts were bridged between the distal donor and proximal donor in 2 cases, one case was reconstructed in a "Y" shape between the artery and the recipient artery, one case was reconnected proximally to the donor artery, and the distal end was anastomosed with the branch end - to - end. Postoperative DSA showed all aneurysms disappeared and the grafts were unobstructed. The average postoperative follow-up was 23.67 months, and there was no recurrence of aneurysms and grafts occlusion, and the mean mRS score was 0.33 at the last follow - up. There were no surgery - related complications after surgery. Conclusions Intracranial -intracranial bypass with interposition graft is an effective method for the treatment of complex intracranial aneurysms, which has the technical advantages of strong flexibility, abundant variants and wide range of indications, and can provide more abundant, safe and effective individualized treatment strategies for cerebrovascular surgeons.

Abstract The frontal branch of middle meningeal artery (MMA) can easily be damaged during revascularization surgery. To precise locate it and minimize its injury, we propose a set of modified craniotomy procedures combined with simple virtual reality (VR) technology based on three-dimensional (3D) Slicer simply, economically, and efficiently. Patients with Moyamoya disease (MMD) and internal carotid artery occlusion (ICAO) who received revascularization from January 2015 to December 2022 were divided into two groups based on the methods used to locate the MMA: traditional methods and precise MMA locating with VR technology. Patient demographics and clinical characteristics were analyzed to compare the preservation rates of MMA. The distances between this artery and bony anatomical landmarks were also measured to better understand its localization. There was no significant difference in baseline characteristics between the two groups. The precise MMA locating group exhibited a significantly higher preservation rate of the frontal branch of MMA (p = 0.037, 91.7% vs. 68.2%). Over 77% of patients had their frontal branch of MMA partially or completely surrounded by bony structures to varying degrees. Therefore, the combination of modified craniotomy procedures, 3D Slicer, and simple VR technology represents an economical, efficient, and operationally simple strategy.

Background: Cerebral Revascularization (CR) remained an indispensable arm in the neurosurgical arsenal, especially managing symptomatic hemisphere with misery perfusion (SHMP). Method: We described an a mid-aged gentleman diagnosed with progressive middle cerebral steno-occlusion following carotid endarterectomy by employing individualized arterial reconstruction with tentative clamping method (TCM) under supervision of intraoperative monitoring. An operative video was also accompanied to demonstrate further details. Conclusion: The optimal treatment strategy for SHMP should be tailored by individuals. The risk of postoperative adverse sequel can be minimized and improved neuro-cognitive status was accomplished with an aid of TCM for such prophylactic procedure. Clinical trial registration: NA. [ABSTRACT FROM AUTHOR]

PurposesMethodsResultsConclusionsTo determine the relationship between carotid artery stenosis (CAS) and the development of open-angle glaucoma (OAG) in the Taiwanese population.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.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).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. [ABSTRACT FROM AUTHOR]

Purpose: Posterior circulation cerebral bypasses often show higher risks and lower patency. Only few reports discussed occipital artery (OA)-vertebral artery (VA) bypasses. We present our illustrative cases to address current gaps in the literature on OA-VA bypass. Methods: A single-center retrospective review was conducted to include all institutional cases of OA-VA bypass, discussing the technique and outcomes. Results: Four institutional cases undergoing a total of 5 bypasses were evaluated, including 3 males and 1 female, with median age of 65 years (range, 62–73). All patients had vertebrobasilar insufficiency (VBI) with recurrent strokes/TIAs due to intracranial atherosclerosis, leading to unilateral VA stenosis with contralateral occlusion (1, 25%), bilateral VA stenosis (1, 25%) or occlusion (1, 25%). Medical management included aspirin for all cases (100%), with clopidogrel in 3 (75%). Surgery was performed through a far lateral approach, connecting the OA to the VA-3 segment, with no inter-positional graft. One patient underwent contralateral OA-VA bypass 6 months after the prior surgery due to worsening of the contralateral VA stenosis. Bypass patency was confirmed in all cases with post-operative angiography. All patients had clinical improvement, with one case of wound dehiscence managed conservatively. All patients were alive at last follow-up (median 7.0 months; range: 1.5–18). Conclusion: OA-VA bypass is a challenging yet effective strategy in selected patients with VBI. Current literature lacks unique definitions of surgical indications and techniques, which we addressed in our series. Surgical education should focus on expanding the microsurgery anatomy knowledge. [ABSTRACT FROM AUTHOR]

Revascularization surgery for the symptomatic hemisphere with hemodynamic impairment is effective for Moyamoya vasculopathy patients. However, careful patient selection is crucial and ideally supported by advanced quantitative hemodynamic imaging. Recently, blood oxygenation level-dependent cerebrovascular reactivity (BOLD-CVR) and quantitative magnetic resonance angiography with non-invasive optimal vessel analysis (qMRA-NOVA) have gained prominence in assessing these patients. This study aims to present the results of BOLD-CVR and qMRA-NOVA imaging along with the changes in cerebral hemodynamics and flow status following flow augmentation with superficial temporal artery–middle cerebral artery (STA-MCA) bypass in our Moyamoya vasculopathy patient cohort. Symptomatic patients with Moyamoya vasculopathy treated at the Clinical Neuroscience Center of the University Hospital Zurich who underwent hemodynamic and flow imaging (BOLD-CVR and qMRA-NOVA) before and after bypass were included in the analysis. Reduced hemispheric volume flow rates, as well as impaired BOLD-CVR, were measured in all 12 patients with Moyamoya vasculopathy before STA-MCA bypass surgery. Following the surgical procedure, post-operative BOLD-CVR demonstrated a non-significant increase in BOLD-CVR values within the revascularized, symptomatic middle cerebral artery territory and cerebral hemisphere. The results of the statistical tests should be viewed as indicative due to the small sample size. Additionally, post-operative qMRA-NOVA revealed a significant improvement in the hemispheric volume flow rate of the affected hemisphere due to the additional bypass flow rate. Our findings affirm the presence of hemodynamic and flow impairments in the symptomatic hemisphere of the Moyamoya vasculopathy patients. Bypass surgery proves effective in improving both BOLD-CVR impairment and the hemispheric volume flow rate in our patient cohort. [ABSTRACT FROM AUTHOR]

Objective To explore the efficacy and advantages of intracranial-intracranial bypass for the treatment of complex intracranial aneurysms. Methods A total of 9 patients with complex intracranial aneurysms who underwent intracranial-intracranial bypass in Xiangya Hospital of Central South University from February 2014 to May 2020 were included, and were treated with grafts bypass or reimplantation of recipient arteries. All cases underwent CTA or DSA to detect the patent of grafts, whether aneurysms were completely clipped or resected and aneurysms recurrence occurred during the follow-up. Modified Rankin Scale (mRS) was used to evaluate the neurological prognosis at discharge and during the follow - up. Results Radial artery (RA) or great saphenous vein (GSV) was used for interposition in 4 cases, and recipient arteries were used for reimplantation in 5 cases. Of 4 cases of interposition, the cavernous sinus seoment of internal carotid artery (ICA)-GSV-ICA bypass was adopted in one case, middle cerebral artery (MCA) M2-RA-M2 bypass in one case, anterior cerebral artery (ACA) A3-GSV-A3 bypass in one case, posterior cerebral artery (PCA) P2 - RA - P2 bypass in one case. Of 5 cases of reimplantation, MCA M2 inferior trunk was reimplanted to M2 superior trunk in one case, ACA A3 was reimplanted to contralateral A3 in 2 cases, the posterior inferior cerebellar artery (PICA) was reimplanted to the anterior inferior cerebellar artery (AICA) in 2 cases. CTA in 3 d postoperatively showed all cases grafts were patent and aneurysms disappeared. After 3 months of discharge, 2 were lost to follow-up. The other 7 cases kept the patency of grafts and no new aneurysms, and were constantly followed up, with an average follow-up time of 30.71 months, and mRS score was 1 or lower. Conclusions Intracranial-intracranial bypass can be applied for complex intracranial aneurysms that are difficult for conventional surgical treatment to solve. Compared with extracranial - intracranial bypass, its grafts are shorter and its hemodynamics features are more in line with physiological conditions. [ABSTRACT FROM AUTHOR]

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Intracranial-intracranial bypass is a crucial treatment for complex intracranial aneurysms, as it not only achieves aneurysm eradication but also ensures perfusion to the bypassed vascular territory. To ensure bypass vessels patency and postoperative neurological recovery in patients with aneurysm, it is necessary to consider multiple characteristics of the aneurysm, donor artery and recipient artery. This comprehensive evaluation enables the selection of appropriate surgical decisions and bypass techniques. In recent years, with the advancement of intracranial-intracranial bypass, several new options including donor artery and recipient artery, anastomosis techniques, graft vessels, and auxiliary techniques have been added for neurosurgeons to choose from. This review aims to introduce the technical advances, surgical experience of intracranial-intracranial bypass for complex intracranial aneurysms, with the intention of facilitating clinical application of intracranial-intracranial bypass. [ABSTRACT FROM AUTHOR]

Introduction: Conventionally, one branch of the superficial temporal artery (STA) is utilized to revascularize the middle cerebral artery (MCA). However, there is the possibility of utilizing both branches of the STA when performing the bypass, characterizing the double-barrel (DB) STA-MCA bypass. Notably, a lack of studies evaluating this technique led the authors to conduct a systematic review and single-arm meta-analysis. Methods: PubMed, Embase and Web of Science were searched systematically for publications of DB-STA-MCA bypass on November 1st, 2023. The findings were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Case reports were not included for statistical analysis purposes. Results: The review included 408 patients and 534 bypasses from 34 studies. The main etiology was Moyamoya disease (64.6%), followed by cerebral ischemia (22.2%) and aneurysms (12.5%). The median of the mean follow-ups of each study was 12.8 months (range 1.5–87.9). The postoperative patency was 100%. The follow-up patency was 98% (95% CI: 96%-100%; I2 = 0%). The procedure-related mortality was 0% (95% CI: 0%-1%; I2 = 0%). Aneurysms obtained 87% (95% CI: 72%-100%; I2 = 4%) of good clinical outcomes, while Moyamoya disease yielded a rate of 70% (95% CI: 10%—100%; I2 = 97%). Ischemic complications occurred at a rate of 6% (95% CI: 2%—11%; I2 = 36%), while hemorrhagic occurred at 6% (95% CI: 1%—11%; I2 = 56%). Hyperperfusion syndrome rate was calculated as 18% (7%—30%; I2 = 55%) for Moyamoya disease. Conclusions: The procedure appears to be safe, with excellent patency rates. The clinical efficacy for ischemic and Moyamoya diseases warrants further standardized robust investigation with a broader number of patients, and aneurysm studies are required to enhance sample sizes. The main complication for the Moyamoya subgroup is hyperperfusion syndrome. [ABSTRACT FROM AUTHOR]

Introduction: At our institution, revascularization after indirect moyamoya surgery is routinely evaluated using magnetic resonance angiography (MRA) rather than catheter angiography. In this paper, we review how revascularization can be visualized on axial MRA and compare its visualization on MRA to that on catheter angiography. We also compare clinical outcomes of patients followed with routine postoperative MRA with outcomes of patients followed with routine catheter angiography. Methods: We retrospectively reviewed the records of all patients treated at our institution who underwent unilateral encephaloduroarteriosynangiosis (EDAS) and/or pial synangiosis between the ages of 1 and 21 years and between December 31, 2003, and May 1, 2021. We included patients who underwent EDAS/pial synangiosis at other hospitals as long as they met all inclusion criteria. Inclusion criteria included having a preoperative MRA within 18 months of surgery and a postoperative MRA 3−30 months after surgery. Clinical outcomes included development of postoperative stroke and transient ischemic attacks (TIAs) and changes in symptoms (improved, unchanged, or worsened), including seizures, balance issues, and headaches. Clinical outcomes were compared between patients who had routine postoperative MRA only versus those who had routine postoperative angiograms, with or without routine MRA. For each surgery, we determined the ratios of the diameters and areas of the donor vessel and the contralateral corresponding vessel, as well as the relative signal intensities of these two vessels, on preoperative and 3- to 30-month postoperative MRA. We did the same for the middle meningeal artery (MMA) ipsilateral to the donor artery and the contralateral MMA. We assessed changes from pre- to post-operation in diameter ratios, area ratios, relative signal intensity, ivy sign, and in brain perfusion on arterial spin labeled (ASL) imaging. MRI and MRA measures of revascularization and flow were compared to Matsushima grades in patients who had postoperative catheter angiograms. Results: Fifty-one operations for 42 unique patients were included. There were no significant differences in the rates of postoperative strokes, postoperative TIAs, changes in symptoms, or new symptoms after surgeries evaluated by routine postoperative MRA versus catheter angiogram (p = 0.282, 1, 0.664, and 0.727, respectively). There were significant associations between greater collateralization on postoperative MRA and greater median increases in preoperative-to-postoperative ratios of donor-vessel-over-contralateral-vessel diameter (p = 0.0461), ipsilateral-MMA-over-contralateral-MMA diameter (p = 0.0135), and the summed donor and ipsilateral MMA diameters over the summed contralateral vessel diameters (p < 0.001). The median increase in the ratio of the donor vessel and contralateral corresponding vessel diameters was significantly higher for Matsushima grade A versus B (p = 0.036). The median increase in the ratio of the sum of donor and ipsilateral MMA diameters over the sum of the contralateral vessel diameters was significantly higher for improved-versus-unchanged perfusion on ASL imaging (p = 0.0074). There was a nonsignificant association between greater postoperative collateralization on MRA and Matsushima grade (p = 0.1160). Conclusion: Cerebral revascularization after EDAS and pial synangiosis can be evaluated on axial MRA by comparing the diameter and/or signal intensity of the donor vessel and corresponding contralateral vessel, as well as the ipsilateral and contralateral MMA, on postoperative-versus-preoperative MRA. The use of routine postoperative MRA rather than catheter angiography does not appear to negatively affect outcomes. [ABSTRACT FROM AUTHOR]

Superficial temporal artery (STA) to middle cerebral artery (MCA) bypass surgery for internal carotid artery (ICA) occlusive disease necessarily requires sufficient external carotid artery (ECA) blood flow. Surgical bypass is therefore precluded if there is common carotid artery (CCA) occlusion. Here we present two such cases: one patient had a CCA occlusion and the other had an ICA occlusion and ECA stenosis. Both had failed medical management, and were therefore treated with angioplasty and stenting of the ECA, followed by STA-MCA bypass. We describe the clinical and radiologic outcomes of these cases, and remark on the potential pitfalls associated with this novel approach. [ABSTRACT FROM AUTHOR]

Complex intracranial aneurysms (CIAs) comprise a subset of lesions with defiant vascular architecture, difficult access, and prior treatment. Surgical management of CIAs is often challenging and demands an assessment on a case-by-case basis. The generational evolution of bypass surgery has offered a long-standing potential for effective cerebral revascularization. Herein, we aim to illustrate a single-center experience treating CIAs. The authors conducted a retrospective analysis of clinical records of patients treated with cerebral revascularization techniques at Hospital Nacional Dos de Mayo, Lima, Peru, during 2018–2022. Relevant data were collected, including patient history, aneurysm features on imaging, preoperative complications, the intraoperative course, aneurysm occlusion rates, bypass patency, neurological function, and postoperative complications. Seventeen patients (70.59% female; median age: 53 years) with 17 CIAs (64.7% saccular; 76.5% ruptured) were included. The most common clinical presentation included loss of consciousness (70.6%) and headaches (58.8%). Microsurgical treatment included first-, second-, and third-generation bypass. In 47.1% of cases, an anastomosis between the superficial temporal artery and the M3 segment was predominantly used, followed by an A3-A3 bypass (29.4%), a superficial temporal artery-M2 bypass (17.6%), and an external carotid artery to M2 bypass (5.9%). The intraoperative aneurysm rupture rate was 11.8%. Postoperative complications included ischemia (40%), cerebrospinal fluid fistulas (26.7%), and pneumonia (20%). At hospital discharge, the median Glasgow Coma Scale score was 14 (range: 10–15). At the 6-month follow-up, 82.4% of patients had a modified Rankin Scale score ≤2, bypass patency was present in all cases, and the morbidity rate was 17.6%. CIAs represent a spectrum of defiant vascular lesions with a poor natural history. Bypass surgery offers the potential for definitive treatment. Our case series illustrated the predominant role of cerebral revascularization of CIAs with a critical case-by-case approach to provide optimal outcomes in a limited-resource setting. [ABSTRACT FROM AUTHOR]

Objective: Cerebral hyperperfusion syndrome (CHS) manifests as a collection of symptoms brought on by heightened focal cerebral blood flow (CBF), afflicting nearly 30% of patients who have undergone superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis. The aim of this study was to investigate whether the amalgamation of magnetic resonance imaging (MRI) fluid-attenuated inversion recovery (FLAIR) and apparent diffusion coefficient (ADC) imaging via MRI can discern cerebral hyperemia after STA-MCA anastomosis surgery. Methods: A retrospective study was performed of patients who underwent STA-MCA anastomosis due to Moyamoya disease or atherosclerotic steno-occlusive disease. A protocol aimed at preventing CHS was instituted, leveraging the use of MRI FLAIR. Patients underwent MRI diffusion with FLAIR imaging 24 hours after STA-MCA anastomosis. A high signal on FLAIR images signified the presence of hyperemia at the bypass site, triggering a protocol of hyperemia care. All patients underwent hemodynamic evaluations, including perfusion MRI, single-photon emission computed tomography (SPECT), and digital subtraction angiography, both before and after the surgery. If a high signal intensity is observed on MRI FLAIR within 24 hours of the surgery, a repeat MRI is performed to confirm the presence of hyperemia. Patients with confirmed hyperemia are managed according to a protocol aimed at preventing further progression. Results: Out of a total of 162 patients, 24 individuals (comprising 16 women and 8 men) exhibited hyperemia on their MRI FLAIR scans following the procedure. SPECT was conducted on 23 patients, and 11 of them yielded positive results. All 24 patients underwent perfusion MRI, but nine of them showed no significant findings. Among the patients, 10 displayed elevations in both CBF and cerebral blood volume (CBV), three only showed elevation in CBF, and two only showed elevation in CBV. Follow-up MRI FLAIR scans conducted 6 months later on these patients revealed complete normalization of the previously observed high signal intensity, with no evidence of ischemic injury. Conclusion: The study determined that the use of MRI FLAIR and ADC mapping is a competent means of early detection of hyperemia after STA-MCA anastomosis surgery. The protocol established can be adopted by other neurosurgical institutions to enhance patient outcomes and mitigate the hazard of permanent cerebral injury caused by cerebral hyperemia. [ABSTRACT FROM AUTHOR]

Purpose: Vessel-encoded arterial spin labeling (VE-ASL) is able to provide noninvasive information about the contribution of individual arteries to the cerebral perfusion. The aim of this study was to compare VE-ASL to the diagnostic standard digital subtraction angiography (DSA) with respect to its ability to visualize vascular territories. Methods: In total, 20 VE-ASL and DSA data sets of 17 patients with Moyamoya angiopathy with and without revascularization surgery were retrospectively analyzed. Two neuroradiologists independently assessed the agreement between VE-ASL and DSA using a 4-point Likert scale (no- very high agreement). Additionally, grading of the vascular supply of subterritories (A1-A2, M1-M6) on the VE-ASL images and angiograms was performed. The intermodal agreement was calculated for all subterritories in total and for the subdivision into without and after revascularization (direct or indirect bypass). Results: There was a very high agreement between the VE-ASL and the DSA data sets (median = 1, modus = 1) with a substantial inter-rater agreement (kw = 0.762 (95% CI 0.561–0.963)). The inter-modality agreement between VE-ASL and DSA in vascular subterritories was almost perfect for all subterritories (k = 0.899 (0.865–0.945)), in the subgroup of direct revascularized subterritories (k = 0.827 (0.738–0.915)), in the subgroup of indirect revascularized subterritories (k = 0.843 (0.683–1.003)), and in the subgroup of never revascularized subterritories (k = 0.958 (0.899–1.017)). Conclusion: Vessel-encoded ASL seems to be a promising non-invasive method to depict the contributions of individual arteries to the cerebral perfusion before and after revascularization surgery. [ABSTRACT FROM AUTHOR]

Significance: Cerebral hyperperfusion syndrome (CHS), characterized by neurologic deficits due to postoperative high cerebral perfusion, is a serious complication of superficial temporal artery-middle cerebral artery (STA-MCA) surgery for moyamoya disease (MMD). Aim: We aim to clarify the importance of assessing pre-anastomosis cerebral microcirculation levels by linking the onset of CHS to pre- and post-anastomosis hemodynamics. Approach: Intraoperative laser speckle contrast imaging (LSCI) measured changes in regional cerebral blood flow (rCBF) and regional blood flow structuring (rBFS) within the cerebral cortical microcirculation of 48 adults with MMD. Results: Following anastomosis, all MMD patients exhibited a significant increase in rCBF (279.60% x 120.00%, p < 0.001). Changes in rCBF and rBFS showed a negative correlation with their respective baseline levels (rCBF, p < 0.001; rBFS, p = 0.005). Baseline rCBF differed significantly between CHS and non-CHS groups (p = 0.0049). The areas under the receiver operating characteristic (ROC) curve for baseline rCBF was 0.753. Hemorrhagic MMD patients showed higher baseline rCBF than ischemic patients (p = 0.036), with a marked correlation between pre- and post-anastomosis rCBF in hemorrhagic cases (p = 0.003), whereas ischemic MMD patients did not. Conclusion: Patients with low levels of pre-anastomosis baseline CBF induce a dramatic increase in post-anastomosis and show a high risk of postoperative CHS. [ABSTRACT FROM AUTHOR]

Purpose: Superficial temporal artery to middle cerebral artery (STA-MCA) direct bypass surgery is the most common surgical procedure to treat moyamoya disease (MMD). Here, we aim to compare the performance of the 3D exoscope in bypass surgery with the gold standard operative microscope. Methods: All direct STA-MCA bypass procedures performed at a single university hospital for MMD between 2015 and 2023 were considered for inclusion. Data were retrospectively collected from patient files and surgical video material. From 2020 onwards, bypass procedures were exclusively performed using a digital three-dimensional exoscope as visualization device. Results were compared with a microsurgical bypass control group (2015–2019). The primary endpoint was defined as total duration of surgery, duration of completing the vascular anastomosis (ischemia time), bypass patency, number of stiches to perform the anastomosis, added stiches after leakage testing of the anastomosis and the Glasgow outcome scale (GOS) at last follow-up as secondary outcome parameter. Results: A total of 16 consecutive moyamoya patients underwent 21 STA-MCA bypass procedures. Thereof, six patients were operated using a microscope and ten patients using an exoscope (ORBEYE® n = 1; AEOS® n = 9). Total duration of surgery was comparable between devices (microscope: 313 min. ± 116 vs. exoscope: 279 min. ± 42; p = 0.647). Ischemia time also proved similar between groups (microscope: 43 min. ± 19 vs. exoscope: 41 min. ± 7; p = 0.701). No differences were noted in bypass patency rates. The number of stiches per anastomosis was similar between visualization devices (microscope: 17 ± 4 vs. exoscope: 17 ± 2; p = 0.887). In contrast, more additional stiches were needed in microscopic anastomoses after leakage testing the bypass (p = 0.035). Conclusion: Taking into account the small sample size, end-to-side bypass surgery for moyamoya disease using a foot switch-operated 3D exoscope was not associated with more complications and led to comparable clinical and radiological results as microscopic bypass surgery. [ABSTRACT FROM AUTHOR]

Superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery has been widely adopted in treating moyamoya disease (MMD). Geometric variations including high tortuosity and stenosis exist in many cases, but the hemodynamic effects have not been comprehensively evaluated. We aim to evaluate the hemodynamic effects of bypass geometry variations based on patient-specific data. In total, 17 patients with MMD who underwent STA-MCA bypass surgery with highly tortuous bypass geometry were included. For each patient, the original 3-dimensional structure of STA-MCA bypass was reconstructed from clinical imaging data. The bypass structure was virtually improved by removing the tortuosity and stenosis. Computational fluid dynamics simulation was performed on both bypass structures under identical patient-specific condition. The simulated hemodynamic parameters of the bypass and its distal branches were compared between the original and virtually improved bypass geometries in all cases using paired t -test or Wilcoxon signed-rank test. The changes of hemodynamic parameters were compared between the cases with and without mild-to-moderate stenosis (44.0–70.3% in diameter) in the bypass using t -test or Mann-Whitney U test. The virtual improvement of bypass geometry significantly increased the flow rate of the bypass and its distal branches (P < 0.05) and decreased the transcranial flow resistance (P < 0.05). The hemodynamic changes in cases with stenosis removal were significantly greater than those without stenosis (P < 0.05). High tortuosity and stenosis can significantly change the hemodynamics of STA-MCA bypass, and the optimization of bypass geometry deserves further consideration. [ABSTRACT FROM AUTHOR]

Introduction The aim of this article was to assess the flow capacity of end-to-side arterial anastomosis depending on the method of its implementation. Materials and Methods The study was conducted on 30 live Wistar rats in vivo, which were randomly divided into three groups. In each group of animals, an end-to-side microanastamosis was performed using three methods of donor artery preparation: 45 degrees (group A), 90 degrees (group B), and arteriotomy according to the "fish mouth" type (group C). The determination of flow capacity of anastomosis by measuring the blood volume flow with transonic flowmeter was performed. Results The obtained average values after the anastomosis were, respectively, 7.335 mL/s (standard deviation [SD]: 2.0771; min: 4.05; max: 10.85), 7.36 mL/s (SD: 0.836 mi: 6.15; max: 8.75), and 6.37 mL/s (SD: 1.247; min: 5.05; max: 9.05). No statistically significant difference in the blood volume flow velocity between all types of anastomoses was obtained (p = 0.251). Conclusion The flow capacity of end-to-side arterial anastomosis does not depend on the chosen method of anastomosis. [ABSTRACT FROM AUTHOR]

A twig-like middle cerebral artery (MCA) is an uncommon lesion in which a plexiform network of small vessels replaces the M1 segment of the MCA. Currently, we have insufficient information for twig-like MCAs. Therefore, a review of the literature using PubMed was conducted. In this review of twig-like MCAs, the following were discussed: the definition, pathogenesis, hemodynamics, associated aneurysm, clinical manifestations, imaging examinations, therapeutic strategies, therapeutic complications and prognosis. In addition, we proposed a reasonable grading system for twig-like MCAs, which is significant. For a twig-like MCA, the pathogenesis is unclear, and congenital and acquired factors can be involved. A twig-like MCA disturbed cerebral hemodynamics. An associated aneurysm can occur in patients with twig-like MCAs. Twig-like MCAs can present subclinically and without clinical symptoms, hemorrhage, or ischemic strokes. Of all the available imaging examinations, digital subtracted angiography is the gold standard. When treating a twig-like MCA, it is feasible to target the associated aneurysm, and extracranial-intracranial bypass can be effective in reducing the risk of strokes, but more evidence is needed. Now, the decision to perform surgery for twig-like MCAs should be made on a case-by-case basis. [ABSTRACT FROM AUTHOR]

Purpose: The first-pass effect (FPE), defined as complete revascularization after a single thrombectomy pass in large vessel occlusion, is a predictor of good prognosis in patients with acute ischemic stroke (AIS) receiving mechanical thrombectomy (MT). We aimed to evaluate obesity-related indicators if possible be predictors of FPE. Methods: We consecutively enrolled patients with AIS who were treated with MT between January 2019 and December 2021 at our institution. Baseline characteristics, procedure-related data, and laboratory test results were retrospectively analyzed. A multivariable logistic regression analysis was performed to evaluate the independent predictors of FPE. Results: A total of 151 patients were included in this study, of whom 47 (31.1%) had FPE. After adjusting for confounding factors, the independent predictors of achieving FPE were low levels of body mass index (BMI) (OR 0.85, 95% CI 0.748 to 0.971), non-intracranial atherosclerotic stenosis (OR 4.038, 95% CI 1.46 to 11.14), and non-internal carotid artery occlusion (OR 13.14, 95% CI 2.394 to 72.11). Patients with lower total cholesterol (TC) (< 3.11 mmol/L) were more likely to develop FPE than those with higher TC (≥ 4.63 mmol/L) (OR 4.280; 95% CI 1.24 to 14.74) Conclusion: Lower BMI, non-intracranial atherosclerotic stenosis, non-internal carotid artery occlusion, and lower TC levels were independently associated with increased rates of FPE in patients with AIS who received MT therapy. FPE was correlated with better clinical outcomes after MT. [ABSTRACT FROM AUTHOR]

Isolated middle cerebral artery dissection (MCAD) is rare but increasingly recognized as a significant clinical entity, particularly in younger adults. Ischemic stroke is the most common manifestation in symptomatic cases but symptoms can vary in severity from headaches to severe neurologic deficits. Due to its rarity and unpredictable clinical course, there is no established treatment strategy for isolated MCAD. Through two case reports, we reviewed the post-operative clinical course of MCAD under different treatment modalities. Case 1 was a 21-year-old woman who presented to the emergency department with headaches and left-side hemiparesis. Isolated MCAD was diagnosed and she was successfully treated with the placement of a self-expandable stent and subsequent chemical angioplasty for post-stent vasospasm. Case 2 was a 35-year-old woman who presented to the emergency department with left-side hemiparesis and dysarthria. Isolated MCAD was diagnosed and she was successfully treated with superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis. [ABSTRACT FROM AUTHOR]

Dissecting posterior inferior cerebellar artery (PICA) aneurysms are uncommon lesions. Their anatomy and the location of the dissection are variable, however, they usually occurs at the origin of the PICA. Dissecting PICA aneurysms generally have non-vascular morphology involving an entire segment of the artery and cannot be cut. Nevertheless, the detection of these vascular lesions has increased latterly, so it is necessary to recognize it and take the appropriate management modalities for these injuries. In this report, we describe a case of a 73-year-old male patient, who presented a history of severe headache, associated with neck stiffness, nausea, vomiting, dizziness, hypoactivity, mental confusion, and walking difficulty. Radiographic investigation with brain computed tomography (CT) showed mild bleeding in a pre-medullary and pre-pontine cistern, and cerebral angiogram showed a dissecting PICA aneurysm. Despite being a challenging treatment, microsurgery management was the chosen modality. It was performed an end-to-end anastomosis between the p2/p3 segments, showing to be effective with good clinical and radiographic outcomes. We discussed an unusual case, reviewing the current literature on clinical presentations, the angiographic characteristics of the dissecting aneurysms of PICA, and evaluating the clinical and angiographic results of patients undergoing microsurgical treatment. [ABSTRACT FROM AUTHOR]

Peripheral artery disease (PAD) is the lower limb manifestation of systemic atherosclerotic disease. PAD may initially present with symptoms of intermittent claudication, whilst chronic limb-threatening ischaemia (CLTI), the end stage of PAD, presents with rest pain and/or tissue loss. PAD is an age-related condition present in over 10% of those aged ≥65 in high-income countries. Guidelines regarding definition, diagnosis and staging of PAD and CLTI have been updated to reflect the changing patterns and presentations of disease given the increasing prevalence of diabetes. Recent research has changed guidelines on optimal medical therapy, with low-dose anticoagulant plus aspirin recommended in some patients. Recently published randomised trials highlight where bypass-first or endovascular-first approaches may be optimal in infra-inguinal disease. New techniques in endovascular surgery have increased minimally invasive options for ever more complex disease. Increasing recognition has been given to the complexity of patients with CLTI where a high prevalence of both frailty and cognitive impairment are present and a significant burden of multi-morbidity and polypharmacy. Despite advances in minimally invasive revascularisation techniques and reduction in amputation incidence, survival remains poor for many with CLTI. Shared decision-making is essential, and conservative management is often appropriate for older patients. There is emerging evidence of the benefit of specialist geriatric team input in the perioperative management of older patients undergoing surgery for CLTI. Recent UK guidelines now recommend screening for frailty, cognitive impairment and delirium in older vascular surgery patients as well as recommending all vascular surgery services have support and input from specialist geriatrics teams. [ABSTRACT FROM AUTHOR]

How brain functions in the distorted ischemic state before and after reperfusion is unclear. It is also uncertain whether there are any indicators within ischemic brain that could predict surgical outcomes. To alleviate these issues, we applied individual brain connectome in chronic steno‐occlusive vasculopathy (CSOV) to map both ischemic symptoms and their postbypass changes. A total of 499 bypasses in 455 CSOV patients were collected and followed up for 47.8 ± 20.5 months. Using multimodal parcellation with connectivity‐based and pathological distortion‐independent approach, areal MR features of brain connectome were generated with three measurements of functional connectivity (FC), structural connectivity, and PageRank centrality at the single‐subject level. Thirty‐three machine‐learning models were then trained with clinical and areal MR features to obtain acceptable classifiers for both ischemic symptoms and their postbypass changes, among which, 11 were deemed acceptable (AUC > 0.7). Notably, the FC feature‐based model for long‐term neurological outcomes performed very well (AUC > 0.8). Finally, a Shapley additive explanations plot was adopted to extract important individual features in acceptable models to generate "fingerprints" of brain connectome. This study not only establishes brain connectomic fingerprint databases for brain ischemia with distortion, but also provides informative insights for how brain functions before and after reperfusion. [ABSTRACT FROM AUTHOR]

Abstract Moyamoya disease (MMD) is a rare stenoocclusive cerebral vasculopathy often treated by neurosurgical revascularization using extracranial-intracranial bypasses to prevent ischemic or hemorrhagic events. Little is known about the vascular risk profile of adult MMD patients compared to the general population. We therefore analyzed 133 adult MMD patients and compared them with data from more than 22,000 patients from the German Health Update database. Patients with MMD showed an age- and sex-adjusted increased prevalence of arterial hypertension, especially in women between 30 and 44 years and in patients of both sexes between 45 and 64 years. Diabetes mellitus was diagnosed significantly more frequently in MMD patients with increasing age, whereas the vascular risk profile in terms of obesity, nicotine and alcohol consumption was similar to that of the general population. Antihypertensive medication was changed one year after surgical revascularization in 67.5% of patients with a tendency towards dose reduction in 43.2% of all patients. After revascularization, physicians need to be aware of a high likelihood of changes in arterial hypertension and should adjust all other modifiable systemic vascular risk factors to achieve the best treatment possible.

The use of the maxillary artery (MA) as a donor has increasingly become an alternative method for cerebral revascularization. Localization difficulties emerge due to rich infratemporal anatomical variations and the complicated relationships of the MA with neuromuscular structures. We propose an alternative localization method via the interforaminal route along the middle fossa floor. Five silicone-injected adult cadaver heads (10 sides) were dissected. Safe and effective localization of the MA was evaluated. The MA displayed anatomical variations in relation to the lateral pterygoid muscle (LPM) and the mandibular nerve branches. The proposed L-shaped perpendicular 2-step drilling technique revealed a long MA segment that allowed generous rotation to the intracranial area for an end-to-end anastomosis. The first step of drilling involved medial-to-lateral expansion of foramen ovale up to the lateral border of the superior head of the LPM. The second step of drilling extended at an angle approximately 90° to the initial path and reached anteriorly to the foramen rotundum. The MA was localized by gently retracting the upper head of the LPM medially in a posterior-to-anterior direction. Considering all anatomical variations, the L-shaped perpendicular 2-step drilling technique through the interforaminal space is an attainable method to release an adequate length of MA. The advantages of this technique include the early identification of precise landmarks for the areas to be drilled, preserving all mandibular nerve branches, the deep temporal arteries, and maintaining the continuity of the LPM. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to investigate the microsurgical anatomy of the superficial temporal artery (STA), explore the relationship between STA length and lumen diameter, and develop a reliable radiologic method for selecting STA segments for bypass surgery. Methods: This study used 10 cadaveric dissections (20 STAs, both sides) and 20 retrospective radiological examinations (40 STAs, both sides), employing curved multiplanar reformation and flow color lookup table (CLUT) DICOM processing. Measurements included vessel lumen diameters and luminal cross-sectional thicknesses 3 mm proximal to the STA bifurcation, 3 mm distal to the frontal branch, 5 cm distal to the frontal branch, 3 mm distal to the parietal branch, and 5 cm distal to the parietal branch. The distance between the STA bifurcation and the superior zygomatic border (SZB) was also measured. In our analysis, descriptive statistics encompassed mean, standard deviation (SD), standard error, minimum and maximum values, and distributions. Comparative statistics were performed using Student's t-test, with statistical significance set at p < 0.05. Results: There were no statistically significant differences between STA measurements of bifurcation distances (p = 0.88) and lumen diameters (p = 0.46) between cadavers and radiological measures. However, lumen thicknesses were larger in frontal branches than parietal branches at the seventh and eighth centimeter (p = 0.012, p = 0.039). Branches became thinner distally from the zygoma in both cadavers and radiological image measurements. Conclusion: The CLUT DICOM processing radiological measures provided the high-precision required to enable pre-surgical vessel selection for extracranial-intracranial bypass. The results show that STA vessel luminal diameters are sufficient (> 1 mm) for bypass surgery in the first 9 cm but gradually decrease after that. Also shown is that the choice of frontal versus parietal branches depends on individual anatomical features; therefore, careful preoperative radiological examination is critical. [ABSTRACT FROM AUTHOR]