Showing papers on "Cerebral Revascularization published in 2017"

Thromboaspiration technique as first approach for endovascular treatment of acute ischemic stroke: initial experience at nine Italian stroke centers

Abstract: Background and purpose Aspiration thrombectomy of large vessel occlusions has made a comeback among recanalization techniques thanks to recent advances in catheter technology resulting in faster recanalization and promising clinical results when used either alone or as an adjunct to stent retriever. This multicenter retrospective study reports angiographic data, complications, and clinical outcome in patients treated with aspiration thrombectomy as the first-line option. Materials and methods We analysed the clinical and procedural data of patients treated from January 2014 to March 2015. Recanalization was assessed according to the Thrombolysis in Cerebral Infarction score. Clinical outcome was evaluated at discharge and after 3 months. Results Overall, 152 patients (mean age 68 years) were treated. Sites of occlusion were 90.8% anterior circulation (including 16.4% tandem extracranial/ intracranial occlusions) and 9.2% basilar artery. In 79 patients administration of intravenous tissue plasminogen activator was attempted. Recanalization of the target vessel was obtained in 115/152 cases (75.6%) whereas direct aspiration alone was successful in 83/152 cases (54.6%) with an average puncture to revascularization time of 44.67 min. Symptomatic intracranial hemorrhage occurred in 7.8% and embolization to new territories in 1.9%. 77 patients (50.6%) had a good outcome at 90day follow-up: 55/96 in the direct aspiration alone group and 22/56 in the aspiration-stent retriever group. Conclusions Direct aspiration thrombectomy appears a feasible technique with good revascularization results achieved in more than half the patients. In light of the self-reported data, inhomogeneous patient selection, absence of a core imaging laboratory, and a nonstandardized approach, the results should be validated in a larger trial.

Neurocognitive Performance After Cerebral Revascularization in Adult Moyamoya Disease

Abstract: Background and Purpose— Cerebral revascularization using EC-IC bypass is widely used to treat moyamoya disease, but the effects of surgery on cognition are unknown. We compared performance on formal neurocognitive testing in adults with moyamoya disease before and after undergoing direct EC-IC bypass. Methods— We performed a structured battery of 13 neurocognitive tests on 84 adults with moyamoya disease before and 6 months after EC-IC bypass. The results were analyzed using reliable change indices for each test, to minimize test–retest variability and practice effects. Results— Twelve patients (14%) showed significant decline postoperatively, 9 patients (11%) improved, and 63 patients (75%) were unchanged. Similar results were obtained when the analysis was confined to those who underwent unilateral (33) or bilateral (51) revascularization. Conclusions— The majority of patients showed neither significant decline nor improvement in neurocognitive performance after EC-IC bypass surgery. Uncomplicated EC-IC bypass seems not to be a risk factor for cognitive decline in this patient population.

Current status of the treatment of blood blister-like aneurysms of the supraclinoid internal carotid artery: A review.

Abstract: Currently, the treatment of blood blister-like aneurysms (BBAs) of the supraclinoid internal carotid artery (ICA) is challenging and utilizes many therapeutic methods, including direct clipping and suturing, clipping after wrapping, clipping after suturing, coil embolization, stent-assisted coil embolization, multiple overlapping stents, flow-diverting stents, covered stents, and trapping with or without bypass. In these therapeutic approaches, the optimal treatment method for BBAs has not yet been defined based on the current understanding of BBAs of the supraclinoid ICA. Therefore, in this study, we aimed to review the literature from PubMed to discuss and analyze the pros and cons of the above approaches while adding our own viewpoints to the discussion. Among the surgical methods, direct clipping was the easiest method if the compensation of the collateral circulation of the intracranial distal ICA was sufficient or direct clipping did not induce stenosis in the parent artery. In addition, the clipping after wrapping technique should be chosen as the optimal surgical modality to prevent rebleeding from these lesions. Among the endovascular methods, multiple overlapping stents (≥3) with coils may be a feasible alternative for the treatment of ruptured BBAs. In addition, flow-diverting stents appear to have a higher rate of complete occlusion and a lower rate of retreatment and are a promising treatment method. Finally, when all treatments failed or the compensation of the collateral circulation of the intracranial distal ICA was insufficient, the extracranial-intracranial (EC-IC) arterial bypass associated with surgical or endovascular trapping, a complex and highly dangerous method, was used as the treatment of last resort.

Treatment of aneurysms in patients with moyamoya disease: a 10-year single-center experience

Abstract: OBJECTIVE Moyamoya disease (MMD) is occasionally accompanied by intracranial aneurysms. The purpose of this study was to delineate the efficacy of the authors' current surgical strategy in the management of MMD-associated aneurysms of different types. METHODS Between January 2007 and March 2016, a consecutive cohort of 34 patients with 36 MMD-associated aneurysms was enrolled in this prospective single-center cohort study. The lesions were classified as peripheral (17 aneurysms) or main trunk aneurysms (13 in the anterior circulation and 6 in the posterior circulation). For the peripheral aneurysms, revascularization with or without endovascular treatment was suggested. For the main trunk aneurysms, revascularization alone, revascularization with aneurysm clipping, or revascularization with aneurysm embolization were used, depending on the location of the aneurysms. RESULTS Of the peripheral aneurysms, 4 were treated endovascularly with staged revascularization, and 13 were treated solely with cerebral revascularization. Of the 13 main trunk aneurysms in the anterior circulation, 10 were clipped followed by revascularization, and 3 were coiled followed by staged cerebral revascularization. Of the 6 main trunk aneurysms in the posterior circulation, 4 underwent endovascular coiling and 2 were treated solely with revascularization. One patient died of contralateral intracerebral hemorrhage 6 months after the operation. No other patients suffered recurrent intracranial hemorrhage, cerebral ischemia, or aneurysm rupture. An angiographic follow-up study showed that all the bypass grafts were patent. Complete occlusion was achieved in all 21 aneurysms that were clipped or embolized. Of the remaining 15 aneurysms that were not directly treated, 12 of 13 peripheral aneurysms were obliterated during the follow-up, whereas 1 remained stable; 1 of 2 posterior main trunk aneurysms remained stable, and the other became smaller. CONCLUSIONS The authors' current treatment strategy may benefit patients with MMD-associated aneurysms.

Long-term Outcome After Multiple Burr Hole Surgery in Children With Moyamoya Angiopathy: A Single-Center Experience in 108 Hemispheres.

Abstract: Background Multiple burr hole (MBH) surgery is a simple, safe, and effective indirect technique of revascularization in moyamoya angiopathy (MM). However, it is not yet recognized as a first-line treatment. Objective To assess the long-term outcome and perioperative complications in a large single-center cohort of children with MM who underwent burr hole surgery. Methods This study is a retrospective analysis of children who underwent surgery for MM in a national reference center for pediatric stroke between 1999 and 2015. Sixty-four children (108 hemispheres, median age 7 years) were consecutively treated. The indication for revascularization was previous stroke or transient ischemic attack (TIA) or rapidly progressive disease on brain magnetic resonance imaging (MRI) and digital subtraction angiography. Children were followed with clinical examinations, telephone interviews, and MRI with any clinical recurrence of stroke or TIA used as the primary endpoint. Surgical mortality and morbidity were documented. Results Sixty-four patients were operated (bilateral MBH n = 39, unilateral procedure n = 25). At a mean follow-up of 4.2 years and 270.6 patient years, 89.1% of patients had not suffered any recurrent stroke or TIA. A second surgery was required in 5 cases after unilateral revascularization, and in 3 cases after bilateral MBH. Mortality associated with the procedure was 0. Postoperative Matsushima angiographic grading was the only predictive factor of ischemic recurrence ( P = .036). Conclusion In pediatric MM, MBH compares favorably to other indirect or direct revascularization techniques in children in the prevention of stroke or TIA.

Revascularization of tandem occlusions in acute ischemic stroke: review of the literature and illustrative case.

Abstract: OBJECTIVE Tandem occlusions continue to represent a major challenge in patients with acute ischemic stroke (AIS). The anterograde approach with proximal to distal revascularization as well as the retrograde approach with distal to proximal revascularization have been reported without clear consensus or standard guidelines. METHODS The authors performed a comprehensive search of the PubMed database for studies including patients with carotid occlusions and tandem distal occlusions treated with endovascular therapy. They reviewed the type of approach employed for endovascular intervention and clinical outcomes reported with emphasis on the revascularization technique. They also present an illustrative case of AIS and concurrent proximal cervical carotid occlusion and distal middle cerebral artery occlusion from their own experience in order to outline the management dilemma for similar cases. RESULTS A total of 22 studies were identified, with a total of 790 patients with tandem occlusions in AIS. Eleven studies used the anterograde approach, 3 studies used the retrograde approach, 4 studies used both, and in 4 studies the approach was not specified. In the studies that reported Thrombolysis in Cerebral Infarction (TICI) grades, an average of 79% of patients with tandem occlusions were reported to have an outcome of TICI 2b or better. One study found good clinical outcome in 52.5% of the thrombectomy-first group versus 33.3% in the stent-first group, as measured by the modified Rankin Scale (mRS). No study evaluated the difference in time to reperfusion for the anterograde and retrograde approach and its association with clinical outcome. The patient in the illustrative case had AIS and tandem occlusion of the internal carotid and middle cerebral arteries and underwent distal revascularization using a Solitaire stent retrieval device followed by angioplasty and stent treatment of the proximal cervical carotid occlusion. The revascularization was graded as TICI 2b; the postintervention National Institutes of Health Stroke Scale (NIHSS) score was 17, and the discharge NIHSS score was 7. The admitting, postoperative, and 30-day mRS scores were 5, 1, and 1, respectively. CONCLUSIONS In stroke patients with tandem occlusions, distal to proximal revascularization represents a reasonable treatment approach and may offer the advantage of decreased time to reperfusion, which is associated with better functional outcome. Further studies are warranted to determine the best techniques in endovascular therapy to use in this subset of patients in order to improve clinical outcome.

Initial experience with SOFIA as an intermediate catheter in mechanical thrombectomy for acute ischemic stroke.

Abstract: Background The benefits of mechanical thrombectomy for emergent large vessel occlusion (ELVO) have been established Combined mechanical/aspiration (Solumbra) and a direct aspiration as a first pass technique (ADAPT) are valid procedures requiring an intermediate catheter for clot suction Recently, SOFIA (Soft torqueable catheter Optimized For Intracranial Access) was developed as a single lumen flexible catheter with coil and braid reinforcement, but its suitability for mechanical thrombectomy had not been evaluated Objective To describe our initial experience with SOFIA in acute stroke intervention and evaluate its efficacy and safety Methods All patients with ELVO undergoing endovascular stroke intervention with SOFIA were identified Demographic, presentation, treatment, and complication data were recorded Primary outcome was Thrombolysis in Cerebral Infarction (TICI) 2b/3 revascularization rate and the number of passes required Secondary outcomes included complication rates and discharge National Institute of Health Stroke Scale (NIHSS) score Results 33 patients with a mean age of 72 years were treated for ELVO with SOFIA and IV tissue plasminogen activator was administered in 67% Vessel occlusion involved the internal carotid artery (152%), M1 (485%), and M2 (242%) segments, and posterior circulation (121%) Median presentation NIHSS score was 14 (IQR 11–19) and discharge NIHSS 4 (IQR 2–14) The Solumbra technique represented 94% of treatments and ADAPT 3% The TICI 2b/3 revascularization rate was 94%, including 485% TICI 3 with an average of 16 passes The symptomatic reperfusion hemorrhage rate was 6% Procedural complications occurred in four patients, but were unrelated to SOFIA Mortality was 21%, secondary to failed revascularization, hemorrhagic transformation, and baseline medical condition Conclusions Mechanical and aspiration thrombectomy with SOFIA is safe and effective with high revascularization rates Its trackability, stability, and luminal size make SOFIA suitable for stroke intervention

Patient Selection and Clinical Efficacy of Urgent Superficial Temporal Artery-Middle Cerebral Artery Bypass in Acute Ischemic Stroke Using Advanced Magnetic Resonance Imaging Techniques

Abstract: BACKGROUND Selected patients with acute ischemic stroke might benefit from superficial temporal artery-middle cerebral artery (STA-MCA) bypass, but the indications for urgent STA-MCA bypass are unknown. OBJECTIVE To report our experiences of urgent STA-MCA bypass in patients requiring urgent reperfusion who were ineligible for other reperfusion therapies, using advanced magnetic resonance imaging (MRI) techniques. METHODS The inclusion criteria for urgent STA-MCA bypass were as follows: acute infarct volume 0.85. From January 2013 to October 2015, 21 urgent STA-MCA bypass surgeries were performed. The control group included 19 patients who did not undergo bypass surgery mainly due to refusal of surgery or the decision of the neurologist. Clinical and radiological data were compared between the surgery and control group. RESULTS The median age of the control group (70 years, interquartile range [IQR] 58-76) was higher than that of the surgery group (62 years, IQR 49-66), but the median preoperative diffusion and perfusion lesion volumes of the surgery group (13.8 mL, IQR 7.5-26.0 and 120.9 mL, IQR 84.9-176.0, respectively) were higher than those of the control group (5.6 mL, IQR 2.1-9.1 and 69.7 mL, IQR 23.9-125.3, respectively). Sixteen (76.2%) patients in the surgery group and 2 (10.5%) patients in the control group had favorable outcomes ( P < .001). Logistic regression analysis identified bypass surgery as the strongest predictive factor. CONCLUSION STA-MCA bypass can be used as a therapeutic tool for acute ischemic stroke. Advanced MRI techniques are helpful for selecting patients and for decision making.

Measuring Cerebral Blood Flow in Moyamoya Angiopathy by Quantitative Magnetic Resonance Angiography Noninvasive Optimal Vessel Analysis

Abstract: Background Moyamoya disease causes progressive occlusion of the supraclinoidal internal carotid artery, and middle, anterior, and less frequently the posterior cerebral arteries, carrying the risk of stroke. Blood flow is often partially reconstituted by compensatory moyamoya collaterals and sometimes the posterior circulation. Cerebral revascularization can further augment blood flow. These changes to blood flow within the cerebral vessels, however, are not well characterized. Objective To evaluate blood flow changes resulting from the disease process and revascularization surgery using quantitative magnetic resonance angiography with noninvasive optimal vessel analysis (NOVA). Methods We retrospectively analyzed 190 preoperative and postoperative imaging scans in 66 moyamoya patients after revascularization surgery. Images were analyzed for blood flow using NOVA and compared with preoperative angiographic staging and postoperative blood flow. Blood flow rates within superficial temporal artery grafts were compared based on angiographic evidence of patency. Results Diseased vessels had lower blood flow, correlating with angiographic staging. Flow in posterior cererbal and basilar arteries increased with disease severity, particularly when both the anterior and middle cerebral arteries were occluded. Basilar artery flow and ipsilateral internal carotid artery flow decreased after surgery. Flow rates were different between angiographically robust and poor direct bypass grafts, as well as between robust and patent grafts. Conclusion Preoperative changes in cerebral vessel flow as measured by NOVA correlated with angiographic disease progression. NOVA demonstrated that preoperative augmentation of the posterior circulation decreased after surgery. This report is the first to quantify the shift in collateral supply from the posterior circulation to the bypass graft.

Cerebral Revascularization for Aneurysms in the Flow-Diverter Era.

Abstract: BACKGROUND Cerebral bypass has been an important tool in the treatment of complex intracranial aneurysms. The recent advent of flow-diverting stents (FDS) has expanded the capacity for endovascular arterial reconstruction. OBJECTIVE We investigated how the advent of FDS has impacted the application and outcomes of cerebral bypass in the treatment of intracranial aneurysms. METHODS We reviewed a consecutive series of cerebral bypasses during aneurysm surgery over the course of 10 years. FDS were in active use during the last 5 years of this series. We compared the clinical characteristics, surgical technique, and outcomes of patients who required cerebral bypass for aneurysm treatment during the preflow diversion era (PreFD) with those of the postflow diversion era (PostFD). RESULTS We treated 1061 aneurysms in the PreFD era (from July 2005 through June 2010) and 1348 in the PostFD era (from July 2010 through June 2015). Eighty-five PreFD patients (8%) and 45 PostFD patients (3%) were treated with cerebral bypass. PreFD patients had better baseline functional status compared to PostFD patients with average preoperative modified Rankin Scale score of 0.55 in PreFD and 1.18 in PostFD. CONCLUSION After the introduction of FDS, cerebral bypass was performed in a lower proportion of patients with aneurysms. Patients selected for bypass in the flow-diverter era had worse preoperative modified Rankin Scale scores indicating a greater complexity of the patients. Cerebral bypass in well-selected patients and revascularization remains an important technique in vascular neurosurgery. It is also useful as a rescue technique after failed FDS treatment of aneurysms.

Hemodynamic Changes after Unilateral Revascularization for Moyamoya Disease: Serial Assessment by Quantitative Magnetic Resonance Angiography.

Abstract: Background Ultrasonic flow meters and quantitative magnetic resonance angiography quantitatively assess flow during hemodynamic evaluation of cerebral ischemia. Although their reliability and reproducibility have been verified, their clinical impact in moyamoya disease has rarely been reported. Objective To investigate flow measurement outcomes in moyamoya disease patients pre- and postoperatively through a retrospective observational study. Methods We evaluated 41 patients undergoing their first revascularization surgery who were followed ≥6 mo. Hemodynamic parameters were recorded preoperatively, at 1 and 6 mo postoperatively, and at the last follow-up. Demographic factors, Suzuki stage, and stroke development were also analyzed. Results Patients' median age was 37 yr (interquartile range [IQR], 27-43), and 16 (39.0%) patients were men. During follow-up, 9 (22.0%) patients experienced postoperative stroke (4 major strokes). Hemodynamic status was improved in 34 (82.9%) patients at the 6-mo follow-up. Median intraoperative flow was 41 mL/min (IQR, 25-59). Bypass flow peaked at 6 mo (median, 67 mL/min; IQR, 35-99). At the 1- and 6-mo follow-ups, ipsilateral hemispheric flow was significantly increased. The median proportion of posterior circulation at 6 mo was 44.4%, significantly lower than the preoperative proportion (50.1%). Abundant intraoperative bypass flow was associated with hemodynamic improvement, while low contralateral hemispheric flow was related with immediate postoperative ischemic stroke. Conclusion Ipsilateral hemispheric flow was increased during 6-mo follow-up, and posterior circulation flow burden was diminished. Abundant intraoperative bypass flow was associated with postoperative hemodynamic improvement. Low preoperative contralateral hemispheric flow was related with immediate postoperative ischemic stroke.

Editorial: Direct versus indirect bypass for moyamoya disease: ongoing controversy

Abstract: In this issue of the Journal of Neurosurgery, Macyszyn and colleagues present a comparative analysis of direct, indirect, and combined revascularization techniques for moyamoya disease in adults and children based on data culled from the available English-language scientific literature.20 They conclude that outcomes after direct revascularization are significantly inferior compared with outcomes after the other two surgical approaches in both patient populations. The authors should be congratulated for attempting to address the controversy regarding the preferred revascularization procedure for moyamoya disease. In our own experience, direct revascularization for moyamoya disease is a very well-established technique, and a number of authors have described excellent results in both adult and pediatric populations.4,7–9,13,14 The main advantages of direct anastomosis over indirect procedures are the ability to augment flow immediately after surgery, a more consistent and higher extent of angiographic collateralization,2,3,5,10,12 and superiority in restoring post-bypass cerebrovascular reserve capacity.5 Direct anastomoses are also associated with excellent clinical outcomes, including a higher rate of symptomatic improvement, lower risk of recurrent ischemia, and increased stroke-free survival compared with indirect bypass.1,11,12 In their comparative analysis of adult patients, the authors included 6 adult series (one of which was our Stanford series), in which 762 cases had direct bypasses and 1524 had indirect bypasses. The perioperative risks of death, ischemic stroke, and intracranial hemorrhage were very similar between the two groups. However, the long-term risk of ischemic stroke in the indirect bypass group (10.5%) far exceeded that in the direct bypass group (1.4%). Interestingly, the authors stated that meta-regression analysis showed no significant increased rate of stroke or hemorrhage with length of follow-up but did not quantify further with regards to which intervention group they were addressing. Additionally, they stated that “indirect revascularization results in over one-half a QALY more than the direct option during the 4-year follow-up. This difference is highly statistically significant (p < 0.001).” However, in analyzing the authors’ Table 4, the expected QALYs in adults at the 4-year follow-up were 3.502 for the direct bypass group and 3.553 for the indirect bypass group; thus, a difference of a 0.05 QALY was obtained. Although this difference might be statistically significant, whether this translates into clinical significance is doubtful. Therefore, based on the data presented by the authors, we believe that direct bypass is still a better revascularization procedure in adults, especially in view of the lower long-term stroke risk. With regard to the comparative analysis in the pediatric cohort, 34 series, including 1900 cases, were included (1526 indirect bypasses, 258 combined procedures, and 116 direct bypasses). The authors then concluded that combined and indirect approaches are both superior to direct revascularization based on the analysis performed in the pediatric population. However, we would like to reiterate that in combined procedures, patients undergo a direct and an indirect component of the revascularization in the same setting. Therefore, the direct component would provide an immediate increase in cerebral perfusion, while the indirect collateralization would take months to form. This is also the case in most direct procedures, wherein after direct superficial temporal artery to middle cerebral artery bypass, the perivascular cuff forms indirect collateralization as seen on follow-up angiograms. Therefore, in our opinion, a more suitable analysis would have been to include the direct and combined groups as a single group to compare with the indirect group, as reported by other authors.12 While going through the case series selected to perform

Graft Occlusion and Graft Size Changes in Complex Internal Carotid Artery Aneurysm Treated by Extracranial to Intracranial Bypass Using High-Flow Grafts with Therapeutic Internal Carotid Artery Occlusion.

Abstract: BACKGROUND Although the extracranial-to-intracranial high-flow bypass (EC-IC HFB) continues to be indispensable for complex aneurysms, the risk factors for the graft occlusion and whether the graft size changes after the bypass have not been well established. OBJECTIVE To evaluate the risk factors for the graft occlusion and to confirm whether graft diameters changed over time. METHODS The data of 75 patients who suffered from complex internal carotid artery (ICA) aneurysms and were treated by EC-IC HFB using radial artery graft (RAG) or saphenous vein graft (SVG) with therapeutic ICA occlusion were evaluated. Clinical and radiological characteristics were compared in patients with and without the graft occlusion by the log-rank test. Graft diameters measured preoperatively, postoperatively, at 6 months, and at 1 year were compared by paired t-test. RESULTS During a follow-up period (median 26.2 months), graft occlusions were seen in 4 patients (5.3%), and these were the SVGs. Only SVG was related to graft occlusion (P < .001). There was a significant increase with time in RAG diameters (preoperative, 3.1 ± 0.41 mm; postoperative, 3.6 ± 0.65 mm; 6 months, 4.3 ± 1.0 mm; 1 year, 4.4 ± 1.0 mm), while there were no significant diameter changes in SVGs. CONCLUSION The present study showed that the SVG was related to the graft occlusion and RAGs gradually enlarged. Unless Allen test is negative, RAG may be better to be used as a graft in EC-IC HFB if therapeutic ICA occlusion is needed.

Superficial Temporal Artery: Distal Posterior Cerebral Artery Bypass through the Subtemporal Approach: Technical Note and Pilot Surgical Cases.

Abstract: Background Posterior cerebral artery (PCA) aneurysms are rare and the majority are fusiform in shape. Proximal occlusion of PCA represents a treatment option for these lesions. However, this procedure carries a high risk of ischemic complications. Objective To describe the technique of trapping a fusiform PCA aneurysm and revascularization of the distal PCA using a superficial temporal artery (STA) graft through the same microsurgical approach. Methods From September 2012 to October 2014, we retrospectively identified 3 patients harboring a fusiform PCA aneurysm (P2 segment aneurysm) who underwent trapping of the aneurysm and reconstruction of the distal PCA through the same subtemporal approach. We analyzed immediate morbidity, surgical complications, and the patency of the bypass to determine the feasibility of this procedure. Results All 3 patients underwent successful trapping of the fusiform PCA aneurysm and revascularization of the distal PCA. The origin of P3 segment or posterior temporal artery (PTA) served as recipient arteries. In all 3 cases, adequate blood flow was evident after performing the STA-P3/PTA bypass. None of the patients experienced a new permanent neurological deficit. At 1-year follow-up, the STA-PTA/PCA bypasses remained patent. Conclusion The STA-P3/PTA bypass through the subtemporal approach is a feasible option to maintain blood flow in cases of PCA fusiform aneurysms requiring trapping of the P2 segment.

Indocyanine green visualization of middle meningeal artery before craniotomy during surgical revascularization for moyamoya disease.

Abstract: The middle meningeal artery (MMA) is well known to function as an important collateral channel to the territory of the anterior cerebral artery in moyamoya disease. This study was aimed to evaluate whether indocyanine green (ICG) videoangiography could visualize the anterior branch of the MMA before craniotomy during surgical revascularization for moyamoya disease. This study included 19 patients who developed TIA, ischemic stroke or hemorrhagic stroke due to moyamoya disease. Plain CT scan and three-dimensional time-of-flight MR angiography were performed in all patients before surgery. All of them underwent superficial temporal artery to middle temporal artery anastomosis and indirect bypass on 27 sides in total. ICG videoangiography could clearly visualize the anterior branch of the MMA in 10 (37%) of 27 sides. The patients with a “visible” MMA are significantly younger than those without. Radiological analysis revealed that ICG videoangiography could visualize it through the cranium when the diameter of the MMA is >1.3 mm and the sphenoid bone thickness over the MMA is 1.3 mm) and thin sphenoid bone (<3.0 mm). ICG videoangiography is a safe and valuable technique to preserve the anterior branch of the MMA during craniotomy for moyamoya disease.

Color Doppler ultrasonography as an alternative tool for postoperative evaluation of collaterals after indirect revascularization surgery in Moyamoya disease

Abstract: The cerebral hypoperfusion caused by chronic progressive stenosis or occlusion of intracranial arteries in moyamoya disease can be treated by direct bypass or indirect revascularization procedures. The extent of collaterals from the external carotid artery (ECA) after indirect revascularization surgery is the key point of angiographic follow-up, and the invasiveness of angiography impelled us to investigate the role of ultrasonography in the evaluation of collaterals. We hypothesized that the collaterals shown on angiography might produce corresponding hemodynamic changes in color Doppler ultrasonography. We prospectively recruited moyamoya patients who underwent indirect revascularization surgery and received both preoperative and postoperative angiography and color Doppler ultrasound studies. The collaterals on angiography were graded according to Matsushima method. A total of 21 patients (age, 17 ± 10.2 years) with 24 operated hemispheres were enrolled. Patients who showed better collateral establishment by angiography had higher end-diastolic velocity (EDV), lower resistance index (RI), and larger flow volume in the superficial temporal artery (STA) and ECA (all p < 0.05). In STA, increase of EDV greater than 13.5 cm/sec or reduction of RI greater than 0.19 after operation corresponded to 94% of Matsushima grade A+B. In ECA, post-operative EDV greater than 22 cm/sec or increase of EDV greater than 6.4 cm/sec also corresponded to 94% of Matsushima grade A+B. Our findings revealed potential roles of color Doppler ultrasonography in identifying patients with poor collaterals after indirect revascularization procedures.

The V3 segment of the vertebral artery as a robust donor for intracranial-to-intracranial interpositional bypasses: technique and application in 5 patients

Abstract: The V3 segment of the vertebral artery (VA) has been studied in various clinical scenarios, such as in tumors of the craniovertebral junction and dissecting aneurysms. However, its use as a donor artery in cerebral revascularization procedures has not been extensively studied. In this report, the authors summarize their clinical experience in cerebral revascularization procedures using the V3 segment as a donor. A brief anatomical description of the relevant techniques is also provided.

Exposure of the External Carotid Artery Through the Posterior Triangle of the Neck: A Novel Approach to Facilitate Bypass Procedures to the Posterior Cerebral Circulation.

Abstract: Background The external carotid artery (ECA) is the main high-flow donor for extracranial-intracranial revascularization procedures However, anatomic restraints limit the availability of ECA in posterior exposures of the craniocervical junction aimed for bypass to distal vertebral artery segments Objective To examine the feasibility and safety of exposure of the ECA through the posterior triangle of the neck Methods A preliminary feasibility study on the posterior neck exposure of the ECA was performed in 1 cadaveric head (2 sides) followed by a morphometric study on 9 cadaveric heads (18 sides) Through an extension of the muscular stage of the far-lateral approach, the fascial plane between the posterior belly of the digastric muscle and the capsule of the parotid gland was dissected inferior to the C1 Topographic anatomy of the exposed distal segment of the ECA was defined in detail, including bony landmarks and the facial nerve Results ECA was found successfully using the proposed technique in all specimens In 90% of the specimens, ECA was exposed without transgression of the capsule of the parotid gland The facial nerve was not encountered during the surgical exposures Conclusion ECA can be safely and effectively exposed through the posterior triangle of the neck using the proposed approach This method can facilitate extracranial-intracranial bypass procedures to V3/V4 vertebral artery Advantages of this novel approach are shortening the graft length and surgical timing, less invasiveness, and optimizing surgical trajectories for completion of both donor and recipient bypass anastomosis

Unilateral Trans-cerebellomedullary Fissure Approach for Occipital Artery to Posterior Inferior Cerebellar Artery Bypass during Aneurysmal Surgery.

Abstract: Occipital artery (OA) to the posterior inferior cerebellar artery (PICA) bypass is indispensable for the management of complex aneurysms of the PICA that cannot be reconstructed with surgical clipping or coil embolization. Although OA-PICA bypass is a comparatively standard procedure, the bypass is difficult to perform in some cases because of the location and situation of the PICA. We describe the usefulness of the unilateral trans-cerebellomedullary fissure (CMF) approach for OA-PICA bypass. Thirty patients with aneurysms in the vertebral artery (VA) or PICA were treated using OA-PICA bypasses between 2010 and 2015. Among them, the unilateral trans-CMF approach was used for OA-PICA anastomosis in 13 patients. The surgical procedures performed on and the medical records of all the patients were retrospectively reviewed. The unilateral trans-CMF approach was performed for two reasons depending on the PICA location or situation: either because the caudal loop could not be used as a recipient artery because of arterial dissection (3 patients) or because the tonsillo-medullary segment that was located in the upper part of the CMF did not have a caudal loop that was large enough (10 patients). The trans-CMF approach provided a good operative field for the OA-PICA bypass and the anastomosis were successfully performed in all patients. When the recipient artery was located in the upper part of the CMF, the unilateral trans-cerebello-medullary fissure approach provided a sufficient operative field for OA-PICA anastomosis.

Evaluation of Encephaloduroarteriosynangiosis Efficacy Using Probabilistic Independent Component Analysis Applied to Dynamic Susceptibility Contrast Perfusion MRI

Abstract: BACKGROUND AND PURPOSE: Indirect cerebral revascularization has been successfully used for treatment in Moyamoya disease and symptomatic intracranial atherosclerosis. While angiographic neovascularization has been demonstrated after surgery, measurements of local tissue perfusion are scarce and may not reflect the reported successful clinical outcomes. We investigated probabilistic independent component analysis and conventional perfusion parameters from DSC-MR imaging to measure postsurgical changes in tissue perfusion. MATERIALS AND METHODS: In this prospective study, 13 patients underwent unilateral indirect cerebral revascularization and DSC-MR imaging before and after surgery. Conventional perfusion parameters (relative cerebral blood volume, relative cerebral blood flow, and TTP) and probabilistic independent components that reflect the relative contributions of DSC signals consistent with arterial, capillary, and venous hemodynamics were calculated and examined for significant changes after surgery. Results were compared with postsurgical DSA studies to determine whether changes in tissue perfusion were due to postsurgical neovascularization. RESULTS: Before surgery, tissue within the affected hemisphere demonstrated a high probability for hemodynamics consistent with venous flow and a low probability for hemodynamics consistent with arterial flow, whereas the contralateral control hemisphere demonstrated the reverse. Consistent with symptomatic improvement, the probability for venous hemodynamics within the affected hemisphere decreased with time after surgery (P = .002). No other perfusion parameters demonstrated this association. Postsurgical DSA revealed an association between an increased preoperative venous probability in the symptomatic hemisphere and neovascularization after surgery. CONCLUSIONS: Probabilistic independent component analysis yielded sensitive measurements of changes in local tissue perfusion that may be associated with newly formed vasculature after indirect cerebral revascularization surgery.