Superficial Temporal Artery To Middle Cerebral Artery Bypass Research Articles

One-Stage Combined Open and Endovascular Treatment Using a Hybrid Operating Room is Safe and Effective for Distal Middle Cerebral Artery Aneurysms

BackgroundAneurysms located in the distal middle cerebral artery (MCA) are relatively rare and lack an established treatment strategy. For distal MCA (DMCA) aneurysms, we performed a one-stage combined procedure of endovascular parent artery occlusion (PAO) with coils and superficial temporal artery to middle cerebral artery (STA-MCA) bypass in a hybrid operating room (HOR). The aim of this study was to evaluate the safety and efficacy of this procedure. MethodsCases of unruptured DMCA aneurysms treated with the one-stage combined PAO and STA-MCA bypass in HOR were retrospectively examined, and patients’ and aneurysmal backgrounds, surgical procedures, and treatment outcomes were analyzed. ResultsSix patients were included in the study. The average maximum diameter of the aneurysms was 14.4 mm. One aneurysm was located at M2 and five at M3. All aneurysms had a fusiform shape. No cases were associated with infection, trauma, or malignant tumors. In all six cases, the combined PAO and STA-MCA bypass was successfully completed. No postoperative hemorrhagic complications occurred. A symptomatic ischemic complication occurred in one case whose symptom disappeared in a week. Three months after surgery, complete obliteration of the aneurysm and patency of the bypass were confirmed in all cases. ConclusionsThe one-stage combined PAO and STA-MCA bypass in the HOR is safe and effective for DMCA aneurysms, potentially serving as a treatment option for this complex aneurysm.

The clinical outcome of emergency superficial temporal artery-to-middle cerebral artery bypass in acute ischemic stroke with large vessel occlusion

The role of superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass in acute ischemic stroke (AIS) is contentious, with no evidence in patients with AIS and large vessel occlusion (AIS-LVO). We conducted a cohort study to assess emergency STA-MCA outcomes in AIS-LVO and a meta-analysis to evaluate STA-MCA outcomes in early AIS treatment. From January 2018 to March 2021, we consecutively recruited newly diagnosed AIS-LVO patients, dividing them into STA-MCA and non-STA-MCA groups. To evaluate the neurological status and outcomes, we employed the National Institutes of Health Stroke Scale (NIHSS) during the acute phase and the modified Rankin Scale (mRS) during the follow-up period. Additionally, we conducted a meta-analysis encompassing all available clinical studies to assess the impact of STA-MCA on patients with AIS. In the cohort study (56 patients), we observed more significant neurological improvement in the STA-MCA group at two weeks (p = 0.030). However, there was no difference in the clinical outcomes between the two groups. Multivariable logistic regression identified the NIHSS at two weeks (OR: 0.840; 95% CI: 0.754–0.936, p = 0.002) as the most critical predictor of a good outcome. Our meta-analysis of seven studies indicated a 67% rate for achieving a good outcome (mRS < 3) at follow-up points (95% CI: 57%–77%, I2 = 44.1%). In summary, while the meta-analysis suggested the potential role of STA-MCA bypass in mild to moderate AIS, our single-center cohort study indicated that STA-MCA bypass does not seem to improve the prognosis of patients who suffer from AIS-LVO.

STA – MCA bypass surgery

Cerebral bypass surgery, such as the STA-MCA (superficial temporal artery to middle cerebral artery) bypass, is a critical procedure aimed at restoring blood flow to oxygen-deprived areas of the brain. This surgery involves rerouting blood from a donor vessel, typically the superficial temporal artery, to a recipient vessel within the brain, bypassing blockages or damaged arteries. Indications for this surgery include Moyamoya disease, aneurysms, skull base tumors, and arterial stenosis. Pre-operative imaging helps in planning the surgery, while post-operative care involves monitoring for complications like stroke and graft occlusion. Although bypass surgery improves blood supply, it does not cure underlying vascular diseases. Thus, patients are advised to adhere to medication regimens and adopt a healthy lifestyle for optimal long-term outcomes. Bypass surgery offers a vital intervention in managing cerebrovascular conditions, emphasizing the importance of multidisciplinary care and patient education.

Novel Method of Calculation of Magnetic Resonance Imaging Perfusion and Comparison of Single versus Double Barrel Superficial Temporal Artery-Middle Cerebral Artery Bypass for Revascularisation in Moya Moya Disease

IntroductionMoyamoya disease (MMD) is characterised by supraclinoid internal carotid artery (ICA) narrowing causing cerebral parenchyma to starve. Direct and indirect revascularisation techniques are the treatment norm. We provide a clinicoradiological comparison of single and double barrel superficial temporal artery to middle cerebral artery (STA-MCA) bypass for MMD. The perfusion in cerebral hemispheres and vessel density in DSA have been evaluated using novel algorithms. MethodsDSA, ASL MR imaging methods and Suzuki, Matsushima, Angiographic Outcome Score (AOS) scales were used to quantify perfusion parameters; modified Rankin score (mRS) was used for clinical evaluation. A novel image processing algorithm was designed to perform analysis of ASL sequences and compare perfusion. Vessel density was calculated using connected component analysis on thresholded DSA images. Results54 hemispheres with MMD underwent STA-MCA bypass 42(77.8%) single barrel and 12 (22.2%) double barrel. Clinical outcome - mRS was significant with p<0.001 in single barrel and p=0.001 in double barrel groups. The overall AOS showed improvement post-operatively (p=0.032).Perfusion analysis was performed in 20 hemispheres (13 single barrel; 7 double barrel). MCA territories showed significant improvement in single barrel (2.72%, p=0.0294) and double barrel groups (12.89%, p=0.025). Vessel density calculated in MCA territory, showed an overall post-op improvement (p=1.75 x 10-8). ConclusionDouble barrel STA-MCA bypass clinically as well as radiologically improves perfusion in the ACA as well as MCA territories in MMD. The novel image processing algorithm is an accurate, objective tool to evaluate perfusion in MR images and vessel density in DSA images of MMD.

Revisiting flow augmentation bypass for cerebrovascular atherosclerotic vaso-occlusive disease: Single-surgeon series and review of the literature.

Despite advances in the nonsurgical management of cerebrovascular atherosclerotic steno-occlusive disease, approximately 15-20% of patients remain at high risk for recurrent ischemia. The benefit of revascularization with flow augmentation bypass has been demonstrated in studies of Moyamoya vasculopathy. Unfortunately, there are mixed results for the use of flow augmentation in atherosclerotic cerebrovascular disease. We conducted a study to examine the efficacy and long term outcomes of superficial temporal artery to middle cerebral artery (STA-MCA) bypass in patients with recurrent ischemia despite optimal medical management. A single-institution retrospective review of patients receiving flow augmentation bypass from 2013-2021 was conducted. Patients with non-Moyamoya vaso-occlusive disease (VOD) who had continued ischemic symptoms or strokes despite best medical management were included. The primary outcome was time to post-operative stroke. Time from cerebrovascular accident to surgery, complications, imaging results, and modified Rankin Scale (mRS) scores were aggregated. Twenty patients met inclusion criteria. The median time from cerebrovascular accident to surgery was 87 (28-105.0) days. Only one patient (5%) had a stroke at 66 days post-op. One (5%) patient had a post-operative scalp infection, while 3 (15%) developed post-operative seizures. All 20 (100%) bypasses remained patent at follow-up. The median mRS score at follow up was significantly improved from presentation from 2.5 (1-3) to 1 (0-2), P = .013. For patients with high-risk non-Moyamoya VOD who have failed optimal medical therapy, contemporary approaches to flow augmentation with STA-MCA bypass may prevent future ischemic events with a low complication rate.

Application of protective superficial temporal artery to middle cerebral artery bypass through the lateral supraorbital approach: Technical note

ObjectiveThe lateral supraorbital (LSO) approach is a minimally invasive craniotomy widely used in the surgical treatment of intracranial aneurysms (IAs). A protective bypass is considered a safety measure in high-risk and complex clipping procedures to maintain distal cerebral flow. However, the protective bypass has so far only been applied through a pterional or larger craniotomy. We aimed to describe the characteristics of the superficial temporal artery to middle cerebral artery (STA-MCA) bypass through the LSO craniotomy to treat complex IAs. MethodsWe retrospectively identified six patients with complex IAs who underwent clipping and a protective STA-MCA bypass through the LSO approach between January 2016 and December 2020. The STA donor artery was harvested through the same curvilinear skin incision with a small extension, and it was anastomosed to the opercular segment of the MCA. Subsequently, aneurysm clipping followed standardized steps. ResultsAnastomosis was successful in all patients. Despite requiring temporary occlusion of the parent artery, all aneurysms were successfully clipped without any neurological deterioration. ConclusionsA protective STA-MCA bypass is feasible through the LSO approach with certain technical modifications. This technique helps protect distal cerebral flow for safe clip placement in the treatment of complex IAs with the associated benefits of a less invasive craniotomy.

Effects of superficial temporal artery to middle cerebral artery bypass on postoperative infarction rates among young children (≤ 5 years old) with moyamoya disease

Revascularization surgery for young children with moyamoya disease (MMD) is challenging. Although indirect revascularization is preferred because of the technical difficulty in direct anastomosis, higher risks of postoperative infarction remain a problem. We aimed to investigate the effect of superficial temporal artery to middle cerebral artery (STA-MCA) bypass on postoperative outcomes during the acute postoperative period in young children ≤ 5years old with MMD. This retrospective study included consecutive young children with MMD who underwent surgical revascularization of the anterior cerebral circulation. Groups were determined according to the procedures performed, namely, the combined (STA-MCA bypass with indirect revascularization) and the indirect revascularization groups. The incidences of radiological or symptomatic infarction, transient neurological events, and new neurological deficits that remained at discharge were compared between groups. Of 38 surgical procedures, there were 23 combined and 15 indirect revascularizations. The median age of the patients was 3.0years, which was significantly different between groups (P < .01). When comparing the postoperative outcomes between groups, the incidences of radiological and symptomatic infarction and new neurological deficits that remained at discharge were significantly lower in the combined revascularization group (P < .05). Logistic regression analysis adjusted for potential confounders found that surgical modality was a statistically significant independent risk factor associated with radiological and symptomatic infarctions (indirect/combined, odds ratio: 10.2; 95% confidence interval: 1.30-79.7; P < .05). STA-MCA bypass combined with indirect revascularization can reduce the incidence of postoperative infarction in young children with MMD and might lead to better neurological outcomes.

Combined direct and indirect superficial temporal artery-to-middle cerebral artery bypass with a hinged bone flap: how I do it.

Superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass is a critical treatment for moyamoya disease and steno-occlusive cerebrovascular disease. Combined bypass (direct + indirect) optimizes the chance of durable flow augmentation but can complicate wound closure from tissue disruption. We describe our technique for combined direct and indirect (encephaloduromyosynangiosis; EDAMS) STA-MCA bypass using a hinged bone flap. In addition to a direct bypass, EDAMS provides multiple sources for indirect revascularization. The hinged bone flap gently approximates the muscle and pia for secondary vascular ingrowth. Combined STA-MCA bypass with a hinged bone flap safely maximizes revascularization potential.

Early Restoration of Hypoperfusion Confirmed by Perfusion Magnetic Resonance Image after Emergency Superficial Temporal Artery to Middle Cerebral Artery Anastomosis.

Emergency superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis in patients with large vessel occlusion who fails mechanical thrombectomy or does not become an indication due to over the time window can be done as an alternative for blood flow restoration. The authors planned this study to quantitatively measure the degree of improvement in cerebral perfusion flow using perfusion magnetic resonance imaging (MRI) after bypass surgery and to find out what factors are related to the outcome of the bypass surgery. For a total of 107 patients who underwent emergent STA-MCA bypass surgery with large vessel occlusion, the National Institute of Health stroke scale (NIHSS), modified Rankin score (mRS), infarction volume, and hypoperfusion area volume was calculated, the duration between symptom onset and reperfusion time, occlusion site and infarction type were analyzed. After emergency STA-MCA bypass, hypoperfusion area volume at post-operative 7 days was calculated and analyzed compared with pre-operative hypoperfusion area volume. The factors affecting the improvement of mRS were analyzed. The clinical status of patients who underwent emergency bypass was investigated by mRS and NIHSS before and after surgery, and changes in infarct volume, extent, degree of collateral circulation, and hypoperfusion area volume were measured using MRI and digital subtraction angiography (DSA). The preoperative infarction volume was median 10 mL and the hypoperfusion area volume was median 101 mL. NIHSS was a median of 8 points, and the last normal to operation time was a median of 60.7 hours. STA patency was fair in 97.1% of patients at 6 months follow-up DSA and recanalization of the occluded vessel was confirmed at 26.5% of patients. Infarction volume significantly influenced the improvement of mRS (p=0.010) but preoperative hypoperfusion volume was not significantly influenced (p=0.192), and the infarction type showed marginal significance (p=0.0508). Preoperative NIHSS, initial mRS, occlusion vessel type, and last normal to operation time did not influence the improvement of mRS (p=0.272, 0.941, 0.354, and 0.391). In a patient who had an acute cerebral infarction due to large vessel occlusion with large ischemic penumbra but was unable to perform mechanical thrombectomy, STA-MCA bypass could be performed. By using time-to-peak images of perfusion MRI, it is possible to quickly and easily confirm that the brain tissue at risk is preserved and that the ischemic penumbra is recovered to a normal blood flow state.

Evidence of STA-MCA Bypass-History and Overseas Articles

The superficial temporal artery to middle cerebral artery(STA-MCA)bypass technique developed by M. Gazi Yaşargil and Raymond M. P. Donaghy in the 1960s was rapidly adopted throughout the world as a procedure for surgical flow augmentation for ischemic cerebrovascular disease(CVD). However, the effectiveness of STA-MCA bypass for atherosclerotic occlusive CVD has not been proven in the extracranial-intracranial(EC-IC)bypass and carotid occlusion surgery studies(COSS), both conducted in the United States. Subsequently, the number of STA-MCA bypasses performed for atherosclerotic CVD decreased globally. In contrast, the Japanese EC-IC Bypass Trial demonstrated the efficacy of STA-MCA bypass for occlusive CVD. The number of research articles reassessing bypass surgery with appropriate indications and high quality of care has recently increased, and carotid and middle cerebral artery occlusion surgery studies designed with careful consideration for several criticisms against COSS are now being conducted in China. This article reviews foreign papers related to STA-MCA bypass for atherosclerotic CVD and describes the current consensus regarding both surgical and medical treatment.

Effects of Aspirin Therapy on Bypass Efficacy and Survival of Patients Receiving Direct Cerebral Revascularization.

Background: Both patency maintenance and neoangiogenesis contribute to cerebrovascular bypass efficacy. However, the combined impact of the aforementioned two indicators on postoperative revascularization following superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass has been less well elucidated. Meanwhile, there is a paucity of evidence with conflicting results about postoperative aspirin therapy. Objective: The objective of the study was to investigate the correlation between aspirin use and STA-MCA bypass efficacy, including patency, postoperative neoangiogenesis, and follow-up outcomes. Methods: A total of 181 MMD patients (201 procedures) undergoing STA-MCA bypass at our institution (2017–2019) were retrospectively reviewed. The bypass efficacy level and postoperative complications were compared between aspirin and non-aspirin groups. Results: Among 95 PS-matched pairs, the aspirin group presented a significantly more favorable bypass efficacy than the non-aspirin group [odds ratio (OR) 2.23, 95% confidence interval (CI) 1.11–4.61; p = 0.026]. Multivariate logistic regression analysis confirmed the profound impact of aspirin as an independent predictor of bypass efficacy [adjusted OR 2.91, 95% CI 1.34–6.68; p = 0.009]. A remarkable negative correlation was found between bypass efficacy and the rate of ischemic complications (Phi = −0.521). Postoperative aspirin therapy was associated with a non-significant trend toward a lower incidence of ischemic events [OR 0.73, 95% CI 0.23–2.19; p = 0.580]. No significant difference in bleeding rates was observed between aspirin and control groups [OR 1.00, 95% CI 0.12–8.48; p = 1.000]. Conclusion: Among patients undergoing STA-MCA bypass procedures, bypass efficacy is a good predictor of follow-up outcomes. Postoperative aspirin therapy can improve patency, neoangiogenesis, and overall bypass efficacy, thereby protecting against postoperative ischemic complications. Clinical Trial Registration: http://www.chictr.org.cn/, identifier CTR2100046178.

Superficial temporal artery to middle cerebral artery bypass for flow augmentation

In the lecture to follow, we provide an in-depth review of superficial temporal artery to middle cerebral artery (STA-MCA) bypass for flow augmentation. We begin with a brief review of the two broad categories of cerebral bypasses as well and the relevant pathologies treated. We then discuss some important landmark trials on the subject of STA-MCA bypass. Next, we focus on patient selection with an emphasis on hemodynamic assessment using non-invasive quantitative imaging methods. Revascularization technique is then described with a corresponding case example and a subsequent discussion on complications and future directions.

Can Evoked Potential Changes during the Superficial Temporal Artery-Middle Cerebral Artery Bypass Surgery Predict Postoperative Improvement of Cerebral Perfusion and Functional Status?

Background: We investigated evoked potential (EP) changes during superficial temporal artery to middle cerebral artery (STA-MCA) bypass surgery and their correlations with imaging and clinical findings postoperatively. Methods: This retrospective study included patients who underwent STA-MCA bypass surgery due to ischemic stroke with large artery occlusion (MB group). Patients who underwent unruptured MCA aneurysm clipping were enrolled in the control group (MC group). Median and tibial somatosensory evoked potentials (SSEP), and motor evoked potentials recorded from the abductor pollicis brevis (APB-MEP) and abductor hallucis (AH-MEP) were measured intraoperatively. Modified Rankin scale (mRS) and perfusion-weighted imaging (PWI) related variables, i.e., mean transit time (MTT) and time to peak (TTP), were assessed. Results: Δmedian SSEP, ΔAPB-MEP, and ΔAH-MEP were significantly higher in the MB group than in the MC group (p = 0.027, p = 0.006, and p = 0.015, respectively). APB-MEP and AH-MEP amplitudes were significantly increased at the final measurement (p = 0.010 and p < 0.001, respectively). The ΔTTP asymmetry index was moderately correlated with ΔAPB-MEP (r = 0.573, p = 0.005) and ΔAH-MEP (r = 0.617, p = 0.002). ΔAPB-MEP was moderately correlated with ΔMTT (r = 0.429, p = 0.047) and ΔmRS at 1 month (r = 0.514, p = 0.015). Conclusions: MEP improvement during STA-MCA bypass surgery was partially correlated with PWI and mRS and could reflect the recovery in cerebral perfusion.

Superficial Temporal Artery to Middle Cerebral Artery Cranial Bypass for Nonmoyamoya Steno-Occlusive Disease in Patients Who Failed Optimal Medical Treatment: A Case Series.

In the post-Carotid Occlusion Surgery Study (COSS) era, multiple reviews suggested subset groups of patients as potential candidates for superficial temporal artery to middle cerebral artery (STA-MCA) bypass. Among them are patients with recurrent strokes despite optimal medical therapy. There is a paucity of data on the outcome of bypass in these specific patients. To examine the safety and efficacy of direct STA-MCA bypass in patients with nonmoyamoya, symptomatic steno-occlusive disease with impaired distal perfusion, who failed optimal medical management or endovascular treatment. A retrospective review was performed to identify patients with cerebrovascular steno-occlusive disease who underwent bypass after symptomatic recurrent or rapidly progressive strokes, despite optimal conservative or endovascular treatment. A total of 8 patients (mean age 60±6 yr) underwent direct or combined direct/indirect STA-MCA bypass between 2016 and 2019. All anastomoses were patent. One bypass carried slow flow. There were no procedure-related permanent deficits. One patient developed seizures which were controlled by medications. A total of 7 out of 8 patients were stable or improved clinically at last follow-up (mean 27.3±13.8 mo) without recurrent strokes. One patient did not recover from their presenting stroke, experienced severe bilateral strokes 4 mo postoperatively, and subsequently expired. Modified Rankin Scale (mRS) improved in 6 patients (75%), remained stable in 1 patient (12.5%), and deteriorated in 1 (12.5%). Good long-term functional outcome was achieved in 5 patients (63%, mRS≤2). Patients with symptomatic, hypoperfused steno-occlusive disease who fail optimal medical or endovascular treatment may benefit from cerebral revascularization. Direct or combined STA-MCA bypass was safe and provided favorable outcomes in this small series.

Efficacy and Safety of Timely Urgent Superficial Temporal Artery-to-Middle Cerebral Artery Bypass Surgery in Patients with Acute Ischemic Stroke: A Single-Institutional Prospective Study and a Pooled Analysis

Background: Clinical outcome in patients with acute ischemic stroke (AIS) caused by large vessel occlusion (LVO) is not satisfactory if reperfusion treatment fails or is not tried. Aims: We aimed to assess the efficacy and safety of urgent superficial temporal-to-middle cerebral artery (STA-MCA) bypass surgery in selected patients. Methods: Patients who were diagnosed with LVO-induced AIS in the anterior circulation but had a failed intra-arterial thrombectomy (IAT) or were not tried due to IAT contraindications were prospectively enrolled. Timely urgent STA-MCA bypass surgery was performed if they showed perfusion-diffusion mismatch or symptom-diffusion mismatch in the acute phase of disease. Clinical and radiological data of these patients were assessed to demonstrate the safety and efficacy of urgent bypass procedures. A pooled analysis of published data on urgent bypass surgery in acute stroke patients was conducted and analyzed. Results: In 18 patients who underwent timely bypass, the National Institutes of Health Stroke Scale (NIHSS) score improved from 12.11 ± 4.84 to 9.89 ± 6.52, 1 week after surgery. Three-month and long-term (9.72 ± 5.00 months) favorable outcomes (modified Rankin Scale [mRS] scores 0–2) were achieved in 50 and 75% of the patients, respectively. The pooled analysis (117 patients from 10 articles, including ours) identified favorable mRS scores in 71.79% patients at 3 months. A significant NIHSS score improvement from 11.51 ± 4.89 to 7.59 ± 5.50 was observed after surgery with significance. Major complications occurred in 3 patients (2.6%, 3/117) without mortality. Conclusions: Urgent STA-MCA bypass surgery can be regarded as a safe optional treatment to prevent cerebral infarct expansion and to improve clinical and radiological outcomes in highly selected patients.

Color Doppler ultrasonography for predicting the patency of anastomosis after superficial temporal to middle cerebral artery bypass surgery

Color Doppler ultrasonography (CDUS) is used to evaluate the surgical success and postoperative hemodynamic changes of patients who receive superficial temporal to middle cerebral artery (STA-MCA) bypass surgery. Previous studies enrolled small populations, and difficulties interpreting the results have limited their use in clinical settings. We attempted to determine the feasibility of using CDUS to evaluate STA hemodynamics and identify the most reliable parameter as a new clinical implication for determining bypass patency. Twenty-six patients who underwent STA-MCA bypass surgery were prospectively enrolled. Four times CDUS and two times digital subtraction angiography (DSA) were performed. The CDUS parameters were compensated using the ratio of the operated to the non-operated sides (R1) and compared before and after surgery (R2). The CDUS parameters are then compared with the patency on DSA by statistical analyses. Increased CDUS parameters of the mean flow rate (MFR) and cross-sectional diameter (CSD) showed significant correlations with good patency on DSA. The R2 at 1 month was identified as the most reliable parameter for predicting the patency in both MFR and CSD. Their cutoff values were 1.475 and 1.15, respectively. CDUS can be utilized for predicting the patency after STA-MCA bypass surgery; if the postoperative (compensated and compared) CDUS parameters increased by more than 47.5% in the MFR or 15% in the CSD, the patency of the anastomosis on DSA would be good.

Surgical Tips for STA-MCA Bypass from Misato Central General Hospital

Superficial temporal artery to middle cerebral artery (STA-MCA) bypass is an essential technique, not just for treating cerebral ischemia but also for assisting aneurysm clipping and compensating for unexpected vascular injuries during surgery.Although it is becoming a more fundamental surgery technique because of the provision of off-the-job training, there are several points that should be considered to achieve successful anastomosis. In this article, we describe important points and tips to consider during STA-MCA bypass.To perform a successful anastomosis, it is important to ensure the following: (1) creation of an operative view without blood and cerebrospinal fluid, (2) selection of a suitable recipient artery, and (3) prevention of anastomosis occlusion.A recipient artery that runs downward from right to left (when the operator is right-handed) is considered suitable because of easier needle handling while suturing. Suturing the backside and inversion of the anastomosis should be avoided to prevent anastomosis occlusion. To avoid suturing the backside, we perform an oval arteriotomy on the recipient artery instead of a linear incision. Furthermore, difficult anastomosis is prioritized, and stay sutures and bilateral sutures are performed by the marked pin method and T-junction bypass when anastomosing in part with a large-diameter branch. To avoid inversion, we require the stitch interval of the donor and recipient arteries to be at a ratio of 6:4. We also tie a knot by pulling the thread from the donor side, which ensures that the inner membranes are attached together.Anastomosis is the most important procedure because the ultimate goal of this operation is to prevent cerebral ischemia by achieving long-term patency. The technique should be unified and simplified so that it is available for even young neurosurgeons.The techniques we have introduced are not difficult or complicated, although they can only be put into practice after acquiring the basic skills. Therefore, young neurosurgeons must continue training and preparing for surgeries.

A Survey of Microsurgical Technique for Extracranial-to-Intracranial Bypass

Extracranial-to-intracranial bypass surgery is a well-established technique that has been practiced for over 50 years. Since then, numerous technical variants have developed nationally and internationally. Based on a survey, to collect information on cerebrovascular bypass surgeons and their background, surgical volume, and technical steps of extracranial-to-intracranial bypasses with focus on superficial temporal artery to middle cerebral artery (STA-MCA) bypass. An electronic survey was distributed among bypass neurosurgeons. Responses were analyzed for national-international variations of STA-MCA bypass surgery techniques. The survey focused on the technical aspects of the surgery itself rather than patient selection or perioperative management. Survey responses were collected from 51 neurosurgeons performing cerebrovascular bypass, from 11 different countries across North America, Europe, and Asia. The largest age block was early-to mid-career (66.7% aged 36-50 years). Most participating surgeons (80.40%) performed less than 20 bypasses annually, whereas a select few surgeons (3) performed more than 50 annually. The most common bypass was STA-M4 MCA bypass with a linear incision (34%) over the parietal branch (44%) and choosing an MCA recipient based on diameter (61.2%). The interrupted anastomosis technique was most common (74%). The results of this electronic survey will help to identify common patterns in STA-MCA bypass surgery and will serve as a guide to other neurosurgeons to modify and improve their technique. Cerebrovascular bypass is still widely practiced, including by young neurosurgeons, who are actively learning from established masters who share their experience.

Quantitative analysis of revascularization in ischemic moyamoya disease via whole-brain computed tomography perfusion: A retrospective single-center study.

Ischemic moyamoya disease (MMD) can be treated with the revascularization of superficial temporal artery to middle cerebral artery (STA-MCA) bypass combined with encephalo-duro-arterio-myo-synangiosis (EDAMS) effectively. The purpose of the present study was to quantify the revascularization of STA-MCA bypass combined with EDAMS via whole-brain computed tomography perfusion (WB-CTP).Seventy-nine consecutive patients with ischemic MMD who admitted to our hospital from August 2012 to October 2018 were carried out STA-MCA bypass combined with EDAMS. WB-CTP was performed at 24 hours prior to operation and 3 months following bypass with a follow-up WB-CTP, respectively. Both automatic analysis of WB-CTP (MIStar, Apollo Medical imaging Technology, Melbourne, Australia) for analyzing values of brain volume in delayed time (DT) >3 seconds and DT > 6 seconds, relative cerebral blood flow (γCBF) < 30% and its mismatch ratio or percentage and diffusion-weighted imaging of magnetic resonance imaging in the ischemic penumbra and the infarct core at the 2 time points were studied for verifying the effectiveness of the combined revascularization. Changes in DT values at MCA-terminal territory after revascularization had been investigated. The dynamic data were with reference to the individual cerebellar arteries.All patients with ischemic MMD underwent STA-MCA bypass combined with EDAMS successfully. The preoperative brain volume in DT > 3 seconds in MCA-terminal territory was significantly larger than that of postoperative one (P < .05) in the ischemic penumbra in ischemic MMD. The mismatch ratio in brain volume of 24 hours prior to revascularization in MCA-terminal territory was significantly lower than that of 3 months (P < .05) following combined revascularization. The percentage of mismatch in brain volume of 24 hours prior to revascularization vs that of 3 months and the value of γCBF < 30% were similar to the above mismatch ratio (P < .05). The ratio of postoperative brain volume in DT > 3 seconds vs DT > 6 seconds indicated no significant differences compared with that of preoperative one (P > .05).The WB-CTP can be regarded as a choice for quantifying the combined revascularization in the ischemic penumbra and the infarct core in ischemic MMD. As proposed methods, brain volume in DT > 3 seconds, the value of γCBF < 30% and mismatch ratio in brain volume in MCA-terminal territory should be paid more attention in assessing the validity of STA-MCA bypass combined with EDAMS in ischemic MMD.

Double-Barrel Extracranial-Intracranial Bypass and Trapping of Dolichoectatic Middle Cerebral Artery Aneurysms: 3-Dimensional Operative Video.

A dolichoectatic intracranial vessel with multiple fusiform aneurysms on the same vessel segment is rare, and usually managed with a bypass with aneurysm trapping. This video demonstrates trapping and a double-barrel superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass to treat two fusiform aneurysms in a left dolichoectatic superior MCA trunk. A 46-year-old man with AIDS presented with aphasia and hemiparesis. IRB approval and patient consent were obtained. Both STA branches (frontal and parietal) were harvested. After widely splitting the sylvian fissure from its proximal portion to the angular gyrus, the two fusiform aneurysms on the superior MCA trunk were identified in the insular recess and the circular sulcus. The outflow artery from each aneurysm was identified and prepared for the bypass. The STA was transected, and both limbs were brought down into the fissure. After trapping the distal aneurysm, an end-to-end anastomosis of the parietal STA branch to the M2 MCA was performed. Thereafter, a second bypass was performed in an end-to-side fashion to an M2 branch from the base of the first aneurysm. The second aneurysm was then trapped. Indocyanine green angiography confirmed the patency of both bypasses. Complete aneurysm occlusion and bypass patency were also confirmed with postoperative angiography. The patient recovered from his pre-operative neurological deficits. This case demonstrates the efficacy of double-barrel STA-MCA bypass in combination with aneurysm trapping in a patient with a complex dolichoectatic superior MCA trunk aneurysm. It also highlights the advantage of using end-to-end anastomosis for deep recipients with limited access.