• Journal of Korean Neurosurgical Society
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• v.60 no.3
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• pp.335-347
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• 2017

Intravenous recombinant tissue plasminogen activator had been the only approved treatment for acute ischemic stroke since its approval in 1995. However, the restrictive time window, numerous contraindications, and its low recanalization rate were all limitations of this modality. Under those circumstances, endovascular stroke therapy went through a great evolution during the past two decades of intravenous thrombolysis. The results of the 2013 randomized trials for endovascular stroke therapy were neutral, although they were limited by insufficient imaging screening at enrollment, early-generation devices with less efficacy, and treatment delays. Huge progress was made in 2015, as there were five randomized clinical trials which all demonstrated the safety and efficacy of endovascular stroke treatment. Despite differences in detail patient enrollment criteria, all 5 trials employed key factors for good functional recovery; (1) screening with non-invasive imaging to identify the proximal occlusion and exclude a large infarct core, (2) using highly effective modern thrombectomy devices mainly with stent retriever, and (3) establishment of a fast workflow to achieve effective reperfusion. The results of those trials indicate that modern thrombectomy devices can allow for faster and more effective reperfusion, which can lead to improved clinical outcomes compared to intravenous thrombolysis alone. These advances in mechanical thrombectomy are promising in the global fight against ischemic stroke-related disability and mortality. Two current mainstreams among such mechanical thrombectomy techniques, "stent retriever thrombectomy" and "direct clot aspiration", are the topic of this review. Stent retriever thrombectomy using Solitaire and Trevo retriever will be firstly discussed. And, the commonalities and the differences between two major clot aspiration thrombectomy techniques; a direct aspiration first pass technique (ADAPT) and forced arterial suction thrombectomy (FAST), will be additionally explained. Finally, details regarding the combination of direct clot aspiration and stent retriever thrombectomy, the switching strategy and the Solumbra technique, will be described.

• Journal of Korean Neurosurgical Society
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• v.58 no.5
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• pp.419-425
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• 2015

Objective : Acute vertebrobasilar artery occlusion (AVBAO) is a devastating disease with a high mortality rate. One of the most important factors affecting favorable clinical outcome is early recanalization. Mechanical thrombectomy is an emerging treatment strategy for achieving a high recanalization rates. However, thrombectomy alone can be insufficient to complete recanalization, especially for acute stroke involving large artery atheromatous disease. The purpose of this study is to investigate the safety and efficacy of mechanical thrombectomy in AVBAO. Methods : Fourteen consecutive patients with AVBAO were treated with mechanical thrombectomy. Additional multimodal treatments were intra-arterial (IA) thrombolysis, balloon angioplasty, or permanent stent placement. Recanalization by thrombectomy alone and multimodal treatments were assessed by the Thrombolysis in Cerebral Infarction (TICI) score. Clinical outcome was determined using the National Institutes of Health Stroke Scale (NIHSS) at 7 days and the modified Rankin Scale (mRS) at 3 months. Results : Thrombectomy alone and multimodal treatments were performed in 10 patients (71.4%) and 4 patients (28.6%), respectively. Successful recanalization (TICI 2b-3) was achieved in 11 (78.6%). Among these 11 patients, 3 (27.3%) underwent multimodal treatment due to underlying atherosclerotic stenosis. Ten (71.4%) of the 14 showed NIHSS score improvement of >10. Overall mortality was 3 (21.4%) of 14. Conclusion : We suggest that mechanical thrombectomy is safe and effective for improving recanalization rates in AVBAO, with low complication rates. Also, in carefully selected patients after the failure of recanalization by thrombectomy alone, additional multimodal treatment such as IA thrombolysis, balloons, or stents can be needed to achieve successful recanalization.

• Journal of Korean Neurosurgical Society
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• v.63 no.4
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• pp.427-432
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• 2020

Three randomized control trials (RCTs), published in 2013, investigated efficacy of mechanical thrombectomy in large vessel occlusions and did not show better results compared to intravenous (IV) recombinant tissue-type plasminogen activator (tPA) alone. However, most clinicians treating stroke consider mechanical thrombectomy as the standard treatment rather than using IV tPA alone. This paradigm shift was based on five RCTs investigating efficacy of mechanical thrombectomy in acute ischemic stroke conducted from 2010 to 2015. They demonstrated that mechanical thrombectomy was effective and safe in acute ischemic stroke with anterior circulation occlusion when performed within 6 hours of stroke onset. There are four reasons underlying the different results observed between the trials conducted in 2013 and 2015. First, the three RCTs of 2013 used low-efficiency thrombectomy devices. Second, the three RCTs used insufficient image selection criteria. Third, following the initial presentation at the hospital, reperfusion treatment required a long time. Fourth, the three RCTs showed a low rate of successful recanalization. Time is the most important factor in the treatment of acute ischemic stroke. However, current trends utilize advanced imaging techniques, such as diffusion-weighted imaging and multi-channel computer tomographic perfusion, to facilitate the detection of core infarction, penumbra, and collateral flows. These efforts demonstrate that patient selection may overcome the barriers of time in specific cases.

• Journal of Korean Neurosurgical Society
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• v.63 no.1
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• pp.14-25
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• 2020

Proximal flow control achieved with a balloon guide catheter (BGC) during endovascular treatment of acute ischemic stroke is reviewed in this article. In clinical practice, BGCs offer a multi-faceted approach for clot retrieval by creating proximal flow arrest, reducing embolic burden, and shortening procedure time. Evaluation of frontline thrombectomy procedures with BGCs revealed advantages of combined use over the conventional guide catheter (CGC), notably in the significant reduction of distal emboli to both the affected and previously unaffected territories. Recently, new measures of early and complete reperfusion at first thrombectomy pass have been identified as independent predictors of improved outcomes, which were consistently demonstrated with use of BGC as a safe and effective option to minimize number of passes during intervention. Prior randomized controlled trials reported the positive correlation between BGC-treated patients and a lower risk of mortality as well as shortened procedure time. While BGC use is more common in stent retriever-mediated mechanical thrombectomy, preliminary data has shown the potential benefit of device application during contact aspiration thrombectomy to achieve successful recanalization. However, the question of which major endovascular strategy reigns superior as a frontline remains to be answered. Along with clinical case assessments, BGC performance during in-vitro simulation was analyzed to further understand mechanisms for optimization of thrombectomy technique.

• Journal of the Korean Society of Radiology
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• v.82 no.2
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• pp.447-454
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• 2021

The authors report a successful thrombectomy using the AngioJet Rheolytic Thrombectomy System (AngioJet) and an embolic protection device in a patient with femorofemoral bypass graft occlusion. Lower extremity CT angiograms showed occlusion in the left-to-right femorofemoral bypass graft. A rheolytic thrombectomy using the AngioJet and balloon angioplasty restored blood flow to the right lower extremity, and distal embolization may be effectively prevented by placing an embolic protection device within the right superficial femoral artery during the procedure.

• Journal of Korean Neurosurgical Society
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• v.59 no.4
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• pp.352-356
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• 2016

Objective : The efficacy and safety of manual aspiration thrombectomy using Penumbra in an acute occlusion of large intracranial arteries has been proven in many previous studies. Our study aimed to retrospectively assess the efficacy and safety of manual aspiration thrombectomy using Penumbra in patients with small vessel occlusions (M2 segment of the MCA). Methods : We conducted a retrospective review of 32 patients who underwent manual aspiration thrombectomy using the Penumbra 4 MAX Reperfusion Catheter for treatment of an M2 occlusion between January 2013 and November 2014. We evaluated immediate angiographic results and clinical outcomes through review of patient electronic medical records. Results : There were slightly more men in this study (M : F=18 : 14) and the median age was 72.5 (age range : 41-90). The rate of successful recanalization (TICI grade ${\geq}2b$) was 84% (27/32). NIHSS at discharge and favorable clinical outcomes at 3 months were significantly improved than baseline. Median initial NIHSS score was 10 (range : 4-25) and was 4 (range : 0-14) at discharge. Favorable clinical outcomes (mRS score ${\leq}2$ at 3 months) were seen in 25 out of 32 patients (78%). There were no procedure-related symptomatic intracerebral hemorrhages. One patient expired after discharge due to a cardiac problem. Conclusion : Manual aspiration thrombectomy might be safe and is capable of achieving a high rate of successful recanalization and favorable clinical outcomes in patients with distal cerebral vessel occlusion (M2).

• Journal of Korean Neurosurgical Society
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• v.67 no.5
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• pp.578-585
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• 2024

Surgical treatment of refractory and extensive cerebral venous sinus thrombosis (CVST) has limited applications. Here, we describe an open, direct sinus thrombectomy in the early phase of extensive CVST. A 49-year-old man with extensive CVST that occurred after the coronavirus disease 2019 (COVID-19) vaccination and affected the drainage of the Labbé vein presented with clinical deterioration and left temporal hemorrhagic infarction. Since the patient had extensive CVST, we determined that systemic anticoagulation and endovascular treatment were not suitable treatment options. Therefore, we decided on an emergency surgical treatment and performed direct surgical thrombectomy. We followed extended suboccipital approach and made multiple incisions on the sinuses, exposing the posterior superior sagittal sinus to the transverse sigmoid junction. Consequently, the clinical condition of the patient dramatically improved, resulting in a favorable outcome with a modified Rankin scale score of 0. Performing emergency open surgical thrombectomy was a technically feasible treatment option that recanalize obstructed sinuses. Importantly, the patient recovered with a good clinical outcome. Early maximal surgical thrombectomy can be an effective and lifesaving method to treat extensive CVST with hemorrhagic infarction.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• v.25 no.3
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• pp.297-305
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• 2023

Objective: The term "weekend effect" refers to an increase in the mortality rate for hospitalizations occurring on weekends versus weekdays. In this study, we investigated whether such an effect exists in patients undergoing mechanical thrombectomy for acute ischemic stroke with large vessel occlusion (currently the standard treatment for this condition) at a single center in Japan. Methods: We surveyed 151 patients who underwent mechanical thrombectomy for acute ischemic stroke with large vessel occlusion (75 and 76 patients were treated during daytime and nighttime, respectively) from January 2019 to June 2021. The items evaluated in this analysis were the rate of modified Rankin Scale ≤2 or prestroke scale, mortality, and procedural treatment time. Results: The rates of modified Rankin Scale ≤2 or prestroke scale and mortality at 90 days after treatment did not differ significantly between daytime and nighttime (41.3% vs. 29.0%, p=0.11; 14.7% vs. 11.8%, p=0.61, respectively). The door-to-groin time tended to be shorter during daytime versus nighttime (57 [IQR: 42.5-70] min vs. 70 [IQR: 55-82]) min, p=0.0507). Conclusions: This study did not reveal differences in treatment outcome between daytime and nighttime in patients undergoing mechanical thrombectomy for acute ischemic stroke with large vessel occlusion. Therefore, the "weekend effect" was not observed in our institution.

• Journal of Korean Neurosurgical Society
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• v.67 no.4
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• pp.477-482
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• 2024

This report introduces a simple method to visualize the captured thrombus in real-time during suction thrombectomy using "contrast-in-stasis technique". It enables visualization of the thrombus captured by a suction catheter as it is being retrieved through the tortuous course of the carotid artery eventually into the guiding catheter. It also offers visual identification of important findings such as fragmentation of thrombus into pieces or loss of thrombus during retrieval, and, therefore, helps clinicians to make further critical decisions during the procedure.

• Journal of Chest Surgery
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• v.54 no.6
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• pp.500-508
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• 2021

Background: The major limitation of arteriovenous graft access is the high incidence of thrombotic occlusion. This study investigated the outcomes of our salvage strategy for thrombosed hemodialysis arteriovenous grafts (including surgical thrombectomy with balloon angioplasty) and evaluated the efficacy of intragraft curettage. Methods: Salvage operations were performed for 290 thrombotic occluded arteriovenous grafts with clinical stenotic lesions from 2010 to 2018. Of these, 117 grafts received surgical thrombectomy and balloon angioplasty from 2010 to 2012 (group A), and 173 grafts received surgical thrombectomy and balloon angioplasty, with an additional salvage procedure using a curette and a graft thrombectomy catheter, from 2013 to 2018 (group B). Outcomes were described in terms of post-intervention primary patency and secondary patency rates. Results: The post-intervention primary patency rates in groups A and B were 44.2% and 66.1% at 6 months and 23.0% and 38.3% at 12 months, respectively (p=0.003). The post-intervention secondary patency rates were 87.6% and 92.6% at 6 months and 79.7% and 85.0% at 12 months, respectively (p=0.623). Multivariate Cox regression analysis demonstrated that intragraft curettage was a positive predictor of post-intervention primary patency (hazard ratio, 0.700; 95% confidence interval, 0.519-0.943; p=0.019). Conclusion: Surgical thrombectomy and balloon angioplasty showed acceptable outcomes concerning post-intervention primary and secondary patency rates. Additionally, intragraft curettage may offer better patency to salvage thrombotic occluded arteriovenous grafts with intragraft stenosis.