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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., (Copyright © 2017 by the Congress of Neurological Surgeons)

Background: It is essential to identify and be aware of the anatomy of the posterior condylar emissary vein (PCEV) for achieving an adequate operative field for the transcondylar fossa approach (TCFA)., Objective: To describe the variations in the drainage patterns of PCEVs and the technical issues encountered in such cases., Methods: This was a retrospective analysis of the anatomy of PCEVs in 104 sides in 52 cases treated by the TCFA. Preoperative findings of multidetector-row computed tomography (CT) and CT venography (CTV) were compared with the intraoperative findings. The drainage patterns were classified as 5 types: the sigmoid sinus (SS), jugular bulb (JB), occipital sinus (OS), anterior condylar emissary vein (ACEV), and marginal sinus (MS)., Results: The SS, JB, ACEV, and OS types were observed in 33 (31.7%), 42 (40.3%), 8 (7.7%), and 1 (1.0%) side(s), respectively. One side (1.0%) each had combined drainage from MS and JB, and ACEV and JB, respectively. In 17 sides (16.3%), the PCEVs and posterior condylar canals could not be identified on CT and CTV., Conclusions: Preoperative CT and CTV findings correlated well with the intraoperative findings. To make a sufficient operative field for TCFA, PCEVs should be appropriately dealt with based on the preoperative knowledge of their running course, pattern, and origin., (Copyright © 2017 by the Congress of Neurological Surgeons)

Background: The application of bypass procedures to the posterior cerebral artery (PCA) in combination with proximal clipping or trapping is a useful option for the treatment of complex posterior circulation aneurysms, especially those of the PCA. Because of its course around the midbrain through various cisterns, different approaches are required to access the PCA., Objective: The presented study analyzes a retrospective case series of bypass procedures to the PCA to investigate the relevant treatment strategies and their outcomes., Methods: Seven patients with bypass procedures to the PCA bypass were analyzed. The location of the aneurysms, approaches, site of anastomosis, bypass patency, pre- and postoperative modified Rankin Scale scores, and transient and permanent morbidity were assessed., Results: Analyzed patients were treated for intracranial aneurysm located on the P2 (n = 3) or P3 (n = 2) of the PCA, bilateral vertebral artery dissecting aneurysm (n = 1) or internal carotid artery-posterior communicating artery aneurysm (n = 1). The following approaches were used: anterior temporal approach (n = 2), anterior temporal approach combined with subtemporal approach (n = 2), combined transpetrosal approach (n = 1), posterior interhemispheric approach (n = 1), and posterior interhemispheric approach with subtemporal approach (n = 1). All bypasses were patent. Permanent morbidity occurred in 2 patients via cognitive dysfunction (n = 1) and hemiparesis (n = 1)., Conclusions: Bypass revascularization of the PCA territory is effective for the treatment of complex vascular lesions affecting the posterior circulation. To address the various surgical segments of the PCA, different approaches are required. Combined approaches allow access to the PCA proximal and distal from the lesion., (Copyright © 2016 Elsevier Inc. All rights reserved.)

OBJECT The revascularization technique, including bypass created using the external carotid artery (ECA), radial artery (RA), and M2 portion of middle cerebral artery (MCA), has remained indispensable for treatment of complex aneurysms. To date, it remains unknown whether diameters of the RA, superficial temporal artery (STA), and C2 portion of the internal carotid artery (ICA) and intraoperative MCA blood pressure have influences on the outcome and the symptomatic watershed infarction (WI). The aim of the present study was to evaluate the factors for the symptomatic WI and neurological worsening in patients treated by ECA-RA-M2 bypass for complex ICA aneurysm with therapeutic ICA occlusion. METHODS The authors measured the sizes of vessels (RA, C2, M2, and STA) and intraoperative MCA blood pressure (initial, after ICA occlusion, and after releasing the RA graft bypass) in 37 patients. Symptomatic WI was defined as presence of the following: postoperative new neurological deficits, WI on postoperative diffusion-weighted imaging, and ipsilateral cerebral blood flow reduction on SPECT. Neurological worsening was defined as the increase in 1 or more modified Rankin Scale scores. First, the authors performed receiver operating characteristic curve analysis for continuous variables and the binary end point of the symptomatic WI. The clinical, radiological, and physiological characteristics of patients with and without the symptomatic WI were compared using the log-rank test. Then, the authors compared the variables between patients with and without neurological worsening at discharge and at the 12-month follow-up examination or last hospital visit. RESULTS Symptomatic WI was observed in 2 (5.4%) patients. The mean MCA pressure after releasing the RA graft (< 55 mm Hg; p = 0.017), mean (MCA pressure after releasing the RA graft)/(initial MCA pressure) (< 0.70 mm Hg; p = 0.032), and mean cross-sectional area ratio ([RA/C2 diameter](2) < 0.40 mm [p < 0.0001] and [STA/C2 diameter](2) < 0.044 mm [p < 0.0001]) were related to the symptomatic WI. All preoperatively independent patients remained independent (modified Rankin Scale score < 3). After adjusting for age and sex, left operative side (p = 0.0090 and 0.038) and perforating artery ischemia (p = 0.0050 and 0.022) were related to neurological worsening at discharge (11 [29%] patients) and at the 12-month follow-up or last hospital visit (8 [22%] patients). CONCLUSIONS Results of the present study showed that the vessel diameter and intraoperative MCA pressure had impacts on the symptomatic WI and that operative side and perforating artery ischemia were related to neurological worsening in patients with complex ICA aneurysms treated by ECA-RA-M2 bypass.

Objective: Extracranial to intracranial (EC-IC) high-flow bypass using radial artery or saphenous vein (SV) graft has remained vital for complex aneurysms. If an Allen test is positive, the radial artery cannot be harvested because of poor palmer collateral circulation. The valves are thought to be one of causes of SV graft failure. Herein we illustrate the "valveless SV graft technique" as bypass conduits., Methods: Between August 2014 and December 2014 at the Department of Neurosurgery at Teishinkai Hospital, 4 patients whose Allen test was positive underwent EC-IC bypass with the valveless SV graft for complex internal carotid artery (ICA) aneurysm. After SV harvesting, we identified the SV valve, cut it, and performed an end-to-end anastomosis using the fish mouth trimming technique. Graft patency was confirmed by computed tomography angiography., Results: We have not encountered any problems related to graft failure, and all valveless SV grafts were patent during the follow-up period (median, 210 days; interquartile range, 93-287 days)., Conclusions: The valveless SV graft technique is a useful technique in patients with complex ICA aneurysms who undergo EC-IC high-flow bypass with therapeutic ICA occlusion and whose Allen tests are positive., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Objective: Giant, or complex, aneurysms of the anterior cerebral artery (ACA) are rare, but their surgical treatment is important. The authors describe their experiences with bypasses for complex ACA aneurysms and discuss the new classification of ACA bypasses, the concept of using bypasses for insurance during the approach to the aneurysm, and simplifying the surgical algorithms for these complex ACA aneurysms., Methods: Over a 19-year period, 7 cases of complex ACA aneurysm were treated with bypasses and reviewed retrospectively. The bypasses were classified into 4 groups according to donor blood flow: internal carotid artery-ACA, external carotid artery-ACA, communicating bypass, and reconstruction bypass of the ipsilateral postcommunicating ACA., Results: The cases included 1 precommunicating aneurysm, 3 communicating aneurysms, 2 postcommunicating aneurysms, and 1 double aneurysm (communicating and postcommunicating). The types of bypass included 1 internal carotid artery-ACA, 6 communicating bypasses, 3 external carotid artery-ACAs, and 2 reconstruction bypass of the postcommunicating ACA. Postoperative modified Rankin Scale scores were 0 (6 cases) and 3 (1 case of a communicating aneurysm with complicated memory disturbance because of infarction). One case revealed asymptomatic infarction., Conclusions: Surgical treatment of complex ACA aneurysms requires knowledge of a variety of bypass techniques. Although the type of bypass should be selected according to patient-specific anatomy and the neurosurgeon's preference, the new classification of bypass-specified ACA aneurysms may alter the way surgeons think about ACA bypasses, and in combination with the concept of the protective bypass, can be used to establish a comprehensive algorithm for each type of complex ACA aneurysm., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background: The revascularization technique has remained indispensable for complex aneurysms. However, risk factors for low-flow related ischemic complications (LRICs) and neurologic worsening (NW) have been less well documented. We evaluated the risk factors for LRICs and NW in 67 patients treated with extracranial to intracranial bypass graft using radial artery or saphenous vein graft for complex internal carotid artery (ICA) aneurysm with ICA occlusion., Methods: Intraoperative middle cerebral artery pressure (MCAP) by backup superficial temporal artery to middle cerebral artery bypass was measured. The MCAP ratio was the ratio of the MCAP after release of the graft bypass to the initial MCAP. LRICs were defined as new neurologic deficits and ipsilateral cerebral blood flow reduction in single-photon emission computed tomography. Early and late NW were defined as an increase in 1 or more modified Rankin Scale at discharge and at the 12-month follow-up examination., Results: During a median follow-up period of 13.3 months, LRICs were observed in 7 patients (10%). The Cox proportional hazards model showed that an MCAP ratio ≤0.80 was significantly related to LRICs. Multivariate logistic regression analysis revealed that perforating artery ischemia was significantly associated with early NW (n = 13, 19%) and late NW (n = 7, 13%). It also showed that LRICs were also significantly related to late NW., Conclusions: The present study showed that regardless of the graft type, the MCAP ratio was associated with LRICs, which were related to late NW in patients with complex ICA aneurysms treated by extracranial to intracranial high-flow bypass graft., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Objective Advanced age is known to be a significant risk factor for the rupture of intracranial aneurysms. The impact of age on outcomes of surgically treated patients with unruptured intracranial aneurysms (UIAs) is less clear. Methods A total of 663 consecutive patients with 823 surgically treated UIAs were evaluated. UIAs, which need bypass surgery including low-flow or high-flow bypass, were defined as complex aneurysms. Aneurysm size was categorized as small (<15 mm), large (15–24 mm), and giant (≥25 mm). In patients without symptoms, a poor outcome is defined as a modified Rankin Scale (mRS) score of 2–6. In those with mRS score higher than 1 as a result of UIA-related symptoms or other comorbidities, a poor outcome is defined as an increase of 1 or more on the mRS. Outcomes were evaluated at the 6-month and 12-month follow-up examinations. Results The mean age was 62 ± 12 years and 650 UIAs (78%) were observed in women. Previously treated aneurysm ( P = 0.009), posterior circulation aneurysm ( P < 0.0001), complex aneurysm ( P < 0.0001), a larger size ( P = 0.011), and perforator territory infarction ( P < 0.0001) were related to poor outcome at 6 months, and posterior circulation aneurysm ( P < 0.0001), complex aneurysm ( P < 0.0001), a larger size ( P = 0.035), and perforator territory infarction ( P = 0.013) were related to poor outcome at 12 months. Age was not associated with poor outcome in patients with UIAs who undertook direct surgery. Conclusions Although risks and benefits of aneurysm treatment in older patients should be carefully considered, surgical treatment of UIAs in the elderly should be considered positively. [ABSTRACT FROM AUTHOR]