Preoperative collateralization depending on posterior components in the prediction of transient neurological events in moyamoya disease.

Changes in local cerebral blood flow (CBF) are a major cause of transient neurological events (TNEs) after revascularization for moyamoya disease (MMD); however, the influence of preoperative collateral pathway development on TNEs has not yet been investigated. This study included 28 hemispheres from 28 consecutive patients with MMD who underwent surgical revascularization, including a superficial temporal artery (STA) to middle cerebral artery (MCA) bypass, between January 2014 and March 2022. The collateralization pathways included the anterior communicating artery (AcomA) collaterals, posterior communicating artery (PcomA) collaterals, transdural collaterals, posterior pericallosal anastomosis, lenticulostriate anastomosis, thalamic anastomosis, and choroidal anastomosis. These collateral pathways were analyzed to identify predictive factors significantly associated with TNEs. TNEs were observed in 11 (39.3%) hemispheres. The development of posterior pericallosal anastomosis and choroidal anastomosis was a significant independent predictor of the occurrence of TNEs after bypass surgery for MMD (P = 0.01, OR 26.9, 95% CI 1.50-480.0; P = 0.002, OR 47.6, 95% CI 2.65-856.6). The development of choroidal and posterior pericallosal anastomosis could be reliable preoperative predictors of TNEs after bypass surgery for MMD. Our results provide useful information for future studies aimed at clarifying the mechanisms underlying TNEs.

"Navigating moyamoya: bridging gaps in neurocognitive outcomes through STA-ACA bypass".

With its bimodal age distribution, higher prevalence in Far East Asian populations, and significant risk of ischemic stroke, Moyamoya disease (MMD) poses a distinctive clinical challenge. In a recently published study by Sho Tsunoda et al., the neurocognitive results of patients with MMD undergoing revascularization surgery were assessed, highlighting the potential advantages of superficial temporal artery to anterior cerebral artery (STA-ACA) direct bypass in ameliorating neuropsychological impairment. Despite its propitious findings, the study's limitations-including a small sample size, single-center design, and lack of long-term follow-up-underscore the need for further research. Future multicenter, prospective trials with larger patient cohorts and comprehensive neurocognitive assessments are essential to validate these results and enhance the generalizability of the findings. This letter emphasizes the importance of robust study designs in advancing our understanding of MMD treatment and ensuring better patient outcomes.

A novel intraoperative "Faucet" technique for assessing patency of superficial temporal artery to middle cerebral artery bypass and for prevention of microemboli.

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.

Application of surgical revascularization technique in giant aneurysm of the extracranial internal carotid artery: technical report.

PURPOSE: The purpose of this study is to illustrate the diagnostic and therapeutic value and clinical significance of surgical revascularization in giant aneurysms of the extracranial internal carotid artery. METHODS: The research team screened a group of cases of giant aneurysms of the extracranial internal carotid artery and analyzed the detailed information of the enrolled patients in terms of their basic clinical characteristics, surgical approaches and clinical prognosis. RESULTS: All patients had a good prognosis, except for one patient who was left with only mild facial nerve palsy (grade II facial paralysis). The results demonstrate that surgical revascularization is effective and safe in the treatment of giant aneurysms of the extracranial internal carotid artery. CONCLUSION: The significant conclusion of this study is to provide an ideal alternative treatment for the treatment of giant aneurysms of the extracranial internal carotid artery. The surgical revascularization technique is a powerful tool for vascular neurosurgeons in the management of complex cerebrovascular diseases when traditional surgical clipping or endovascular interventions encounter bottlenecks.

Exploring the Impact of Hemoglobin on Cerebral Blood Flow in Arterial Territories and Surgical Outcomes: Potential Implications for Moyamoya Disease Treatment.

BACKGROUND: Changes in levels of hemoglobin would result in alterations of cerebral blood flow (CBF). However, the impact of hemoglobin on CBF in moyamoya disease (MMD) remains largely unknown. This study sought to determine whether CBF would be influenced by hemoglobin before surgical revascularization and to analyze the relationships between hemoglobin and CBF with clinical outcome after surgery in patients with MMD. METHODS AND RESULTS: We prospectively enrolled adult patients with MMD undergoing surgical revascularization between June 2020 and December 2022. Preoperative CBF was measured in the territories of anterior, middle, and posterior cerebral arteries (ACA, MCA, and PCA, respectively) using 3-dimensional pseudo-continuous arterial spin labeling magnetic resonance imaging. Clinical outcome at 1 year after surgery was evaluated using the modified Rankin Scale. A total of 60 patients with MMD were included, with 25% (n=15) experiencing unfavorable outcomes. Patients with MMD exhibited lower CBF (ACA: P=0.007; MCA: P<0.001; PCA: P=0.014), compared with healthy controls (n=40). Hemoglobin was negatively and significantly associated with CBF (ACA: ß=-0.45, P<0.001; MCA: ß=-0.38, P<0.001; PCA: ß=-0.54, P<0.001). CBF rather than hemoglobin was significantly related with clinical outcome (ACA: P<0.001; MCA: P<0.001; PCA: P=0.001), and CBF showed high discrimination in predicting clinical outcome (ACA: area under the curve, 0.84; MCA: area under the curve, 0.84; PCA: area under the curve, 0.80). CONCLUSIONS: Our findings demonstrate that hemoglobin significantly influences CBF, and CBF has a high predictive value for clinical outcome in MMD. The optimal hemoglobin level before surgical revascularization should be further investigated.

The impact of hypertension on clinical outcomes in moyamoya disease: a multicenter, propensity score-matched analysis.

BACKGROUND: Moyamoya disease (MMD) is a rare cerebrovascular disorder characterized by progressive steno-occlusive changes in the internal carotid arteries, leading to an abnormal vascular network. Hypertension is prevalent among MMD patients, raising concerns about its impact on disease outcomes. This study aims to compare the clinical characteristics and outcomes of MMD patients with and without hypertension. METHODS: We conducted a multicenter, retrospective study involving 598 MMD patients who underwent surgical revascularization across 13 academic institutions in North America. Patients were categorized into hypertensive (n=292) and non-hypertensive (n=306) cohorts. Propensity score matching (PSM) was performed to adjust for baseline differences. RESULTS: The mean age was higher in the hypertension group (46 years vs. 36.8 years, p < 0.001). Hypertensive patients had higher rates of diabetes mellitus (45.2% vs. 10.7%, p < 0.001) and smoking (48.8% vs. 27.1%, p < 0.001). Symptomatic stroke rates were higher in the hypertension group (16% vs. 7.1%; OR: 2.48; 95% CI: 1.39-4.40, p = 0.002) before matching. After PSM, there were no significant differences in symptomatic stroke rates (11.1% vs. 7.7%; OR: 1.5; CI: 0.64-3.47, p = 0.34), perioperative strokes (6.2% vs. 2.1%; OR 3.13; 95% CI: 0.83-11.82, p = 0.09), or good functional outcomes at discharge (93% vs. 92.3%; OR 1.1; 95% CI: 0.45-2.69, p = 0.82). CONCLUSION: No significant differences in symptomatic stroke rates, perioperative strokes, or functional outcomes were observed between hypertensive and non-hypertensive Moyamoya patients. Appropriate management can lead to similar outcomes in both groups. Further prospective studies are required to validate these findings.

Moyamoya Periventricular Choroidal Collateral Registry-A Multicenter Cohort Study of Moyamoya Disease with Choroidal Anastomosis: Study Protocol.

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.

Intracranial bypass for giant aneurysms treatment assessed by computational fluid dynamics (CFD) analysis.

Unruptured giant intracranial aneurysms (GIA) are those with diameters of 25 mm or greater. As aneurysm size is correlated with rupture risk, GIA natural history is poor. Parent artery occlusion or trapping plus bypass revascularization should be considered to encourage intra-aneurysmal thrombosis when other treatment options are contraindicated. The mechanistic background of these methods is poorly studied. Thus, we assessed the potential of computational fluid dynamics (CFD) and fluid-structure interaction (FSI) analyses for clinical use in the preoperative stage. A CFD investigation in three patient-specific flexible models of whole arterial brain circulation was performed. A C6 ICA segment GIA model was created based on CT angiography. Two models were then constructed that simulated a virtual bypass in combination with proximal GIA occlusion, but with differing middle cerebral artery (MCA) recipient vessels for the anastomosis. FSI and CFD investigations were performed in three models to assess changes in flow pattern and haemodynamic parameters alternations (wall shear stress (WSS), oscillatory shear index (OSI), maximal time averaged WSS (TAWSS), and pressure). General flow splitting across the entire domain was affected by virtual bypass procedures, and any deficiency was partially compensated by a specific configuration of the circle of Willis. Following the implementation of bypass procedures, a reduction in haemodynamic parameters was observed within the aneurysm in both cases under analysis. In the case of the temporal MCA branch bypass, the decreases in the studied parameters were slightly greater than in the frontal MCA branch bypass. The reduction in the magnitude of the chosen area-averaged parameters (averaged over the aneurysm wall surface) was as follows: WSS 35.7%, OSI 19.0%, TAWSS 94.7%, and pressure 24.2%. FSI CFD investigation based on patient-specific anatomy models with subsequent stimulation of virtual proximal aneurysm occlusion in conjunction with bypass showed that this method creates a pro-thrombotic favourable environment whilst reducing intra-aneurysmal pressure leading to shrinking. MCA branch recipient selection for optimum haemodynamic conditions should be evaluated individually in the preoperative stage.

Indications, operative techniques, and outcomes of occipital artery-vertebral artery bypass: an institutional series.

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.

Ultrasonographic Predictors for Post-operative Ischemic Events After Indirect Revascularization Surgeries in Patients with Moyamoya Disease.

OBJECTIVE: Recurrent stroke after revascularization surgeries predicts poor outcome in patients with moyamoya disease (MMD). Early identification of patients with stroke risk paves the way for rescue intervention. This study aimed to investigate the role of ultrasound in identifying patients at risk of post-operative ischemic events (PIEs). METHODS: This prospective study enrolled patients with symptomatic MMD who underwent indirect revascularization surgeries. Ultrasound examinations were performed preoperatively and at 3 mo post-operatively to evaluate the hemodynamic changes in extracranial and intracranial arteries on the operated side. PIE was defined as ischemic stroke or transient ischemic attack in the operated hemisphere within 1 y. The areas under receiver operating characteristic curves were compared between models for prediction of PIE. RESULTS: A total of 56 operated hemispheres from 36 patients (mean age, 23.0 ± 18.5 y) were enrolled in this study, and 27% developed PIE. In multivariate logistic regression models, PIE was associated with lower end-diastolic velocity and flow volume (FV) of the ipsilateral external carotid artery (ECA), and lower FV of ipsilateral superficial temporal artery and occipital artery at 3 mo post-operatively (all p < 0.05). Moreover, the post-operative FV of the ipsilateral ECA was the only one factor that significantly increased the areas under receiver operating characteristic curves from 0.727 to 0.932 when adding to a clinical-angiographic model for prediction of PIE (p = 0.017). This parameter was significantly lower in hemispheres with PIE, both in adult and pediatric patients. CONCLUSION: After indirect revascularization, surgeries in patients with symptomatic MMD, FV of ipsilateral ECA at 3 mo helps clinicians to identify patients at risk of PIE.

How i do it: individualized bypass strategy with tentative clamping method.

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.

Influence of an improvement in frontal lobe hemodynamics on neurocognitive function in adult patients with moyamoya disease.

BACKGROUND: In adults, moyamoya disease (MMD) often presents with slight neurocognitive impairment, which may result from frontal lobe hemodynamic insufficiency. METHODS: In this study, we performed revascularization surgery by superficial temporal artery-anterior cerebral artery (ACA) direct bypass in 20 adults with MMD with poor anterograde ACA flow (Group M). The pre- and postoperative neurocognitive test results of these patients were retrospectively analyzed. The comparative group (Group C) included 23 patients with unruptured aneurysms or brain tumors who underwent craniotomy, as well as the same neurocognitive tests as Group M. We calculated the compositive frontal lobe function index (CFFI) based on the results of seven neurocognitive tests for each patient, and the difference between the pre- and postoperative CFFI values (CFFI Post - Pre) was compared between the two groups. RESULTS: Frontal perfusion improved postoperatively in all patients in Group M. The CFFI Post - Pre was significantly higher in Group M than in Group C (0.23 ± 0.44 vs. - 0.20 ± 0.32; p < 0.001). After adjusting for postoperative age, sex, preoperative non-verbal intelligence quotient, and preoperative period of stress, Group M had a significantly higher CFFI Post - Pre than Group C in the multiple regression analysis (t value = 4.01; p < 0.001). CONCLUSION: Improving frontal lobe hemodynamics might be the key for improving neurocognitive dysfunction in adults with MMD. The surgical indication and method should be considered from the perspective of both stroke prevention and neurocognitive improvement or protection.

Indications for cerebral revascularization for moyamoya syndrome in pediatric sickle cell disease determined by Delphi methodology.

OBJECTIVE: Cerebral revascularization surgery (CRS) has been used to prevent stroke in children with sickle cell disease (SCD) and cerebral vasculopathy (e.g., moyamoya syndrome). While results suggest that it may be an effective treatment, surgical indications have not been well defined. This study sought to determine indications for offering revascularization surgery in centers with established sickle cell programs in the US. METHODS: Three sequential surveys utilizing the Delphi methodology were administered to neurosurgeons participating in the Stroke in Sickle Cell Revascularization Surgery study. Respondents were presented with clinical scenarios of patients with SCD and varying degrees of ischemic presentation and vasculopathy, and the group's agreement to offer surgical revascularization was measured. Consensus was defined as ≥ 75% similar responses. RESULTS: The response rate to all 3 surveys was 100%. Seventeen neurosurgeons from 16 different centers participated. The presence of moyamoya collaterals (MMCs) and arterial stenosis matching an ischemic distribution yielded the strongest recommendations to offer surgery. There was consensus to offer revascularization in the presence of MMCs and at least 50% arterial stenosis matching an ischemic distribution. In contrast, there was no consensus to offer revascularization with 50%-70% stenosis not matching an ischemic presentation in the absence of MMCs. The presence of the ivy sign in the distribution of the stenotic artery also contributed to the consensus to offer surgery in certain scenarios. CONCLUSIONS: There were several clinical scenarios that attained consensus to offer surgery; the strongest was moderate to severe arterial stenosis that matched the distribution of ischemic presentation in the presence of MMCs. Radiological findings of decreased cerebral flow or perfusion also facilitated attaining consensus to offer surgery. The findings of this study reflect expert opinion about questions that deserve prospective clinical research. Determination of indications for CRS can guide clinical practice and aid the design of prospective studies.

Advancing Neurosurgical Skills: A Comparative Study of Training Models for Intra-Extracranial Cerebral Bypass.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

[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.

STA-MCA Double-Barrel Bypass: A Systematic Review of Technique and Single-Arm Meta-Analysis of Outcomes.

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.

The impact of an anomalous third segment of the vertebral artery on bypass surgery: a case report and literature review.

The horizontal part of the third segment (V3) of the vertebral artery (VA) is a critical anastomotic site for bypass procedures involving either donor or recipient vessels. It is rare for the V3 segment to deviate from its typical course of passing through the atlanto-transverse foramen. V3 anomaly encountered in occipital artery (OA)-V3 bypass surgery has not been previously reported. Here, we present a case involving a patient undergoing bypass surgery due to recurrent post-stent occlusion at the first segment (V1) of the left VA. During the operation, it was noted that the V3 horizontal segment could not be identified within the left VA groove, leading to initial suspicion of left V3 disuse atrophy attributed to prolonged chronic ischaemia. Consequently, there was a need to modify the operative method and to transition from an OA-V3 bypass to an OA-posterior inferior cerebellar artery bypass. Post-operative computed tomography angiography confirmed that indeed, the left V3 did not traverse through the transverse foramen of the atlas and instead entered the dural membrane between the first cervical vertebra (C1) and the second cervical vertebra (C2).

Analysis of rescue strategies for acute thrombosis during STA-MCA bypass surgery and the literature review.

BACKGROUND AND OBJECTIVES: STA-MCA bypass surgery is mainly used for Moyamoya disease, giant intracranial aneurysms, and resection of intracranial tumors requiring sacrifice of blood vessels. The intraoperative patency of the reconstructive vessels is critical to the efficacy of the procedure. This study aimed to evaluate the efficacy of intra-arterially infused tirofiban for the treatment of acute thrombosis during STA-MCA bypass surgery and countermeasures for acute thrombosis. METHODS: This study involved 209 patients (272 hemispheres) who underwent STA-MCA surgery between November 2020 and December 2023. Intraoperative acute thrombosis occurred in eight patients (3.83%,8 hemispheres). We retrospectively reviewed the clinical and imaging data, surgical procedure, and follow-up outcomes of eight patients. We implemented the different thrombolytic methods to evaluate the optimal thrombosis management during the bypass surgery. After three months, we assessed neurological functions using the modified Rankin Scale (mRS) and conducted a literature review using PubMed. RESULTS: Eight patients (four male patients and four female patients) developed acute thrombosis during the bypass surgery. Of the eight patients, two underwent re-anastomosis after thrombus removal, three received local injections of tirofiban into the anastomosis or the branches of the superficial temporal artery, and three underwent superselective intra-arterial tirofiban infusion using a microcatheter. Thrombosis were resolved, and arteries were recanalized in all patients. The mRS score was 0 in all patients. No major ischemic or hemorrhagic complications occurred. CONCLUSION: Our treatment methods were efficacious in the management of acute thrombosis. Intra-arterial tirofiban administration seems to be a simple and effective treatment option for acute thrombosis during STA-MCA bypass surgery.