Predictor of Visual Impairment Following Paraclinoid Aneurysm Surgery: Special Consideration of Surgical Microanatomy Related to Paraclinoid Structures.

BACKGROUND: Microsurgical clipping with extradural anterior clinoidectomy (EDAC) for paraclinoid aneurysm is an established technique with good angiographic outcomes, although postoperative worsening of visual acuity remains a concern. Multiple reports show visual acuity deteriorating after clipping, yet the cause remains unclear. OBJECTIVE: To analyze results of asymptomatic paraclinoid aneurysm surgeries treated with EDACs, specifically focusing on the microanatomy of paraclinoid structure dissection. This determined the causes of delayed visual impairment and microsurgical indications. METHODS: Results of the treatment with EDAC of 94 patients with cerebral aneurysm and normal preoperative visual acuity but also full visual fields were retrospectively analyzed. RESULTS: The mean aneurysm size was 6.2 (±3.3) mm. Clipping was performed in 87 cases and trapping in 7 cases. Complete angiographic occlusion was observed in 91 patients. In 26 cases, a postoperative visual deficit occurred. A total of 20 cases exhibited partial visual field deficits, including 5 who were asymptomatic. Visual deficits were only detectable by postoperative ophthalmologic testing. Six showed light perception impairment or blinding. Of the 15 patients with symptomatic partial visual field deficits, 5 showed improvement at follow-up. Visual deficits persisted in 22 patients at the last follow-up. Multivariate logistic regression analysis revealed that medial projecting aneurysm (adjusted odds ratio [OR]: 10.43) and the opening of the carotidoculomotor membrane (adjusted OR: 5.19) were significantly related to visual impairment. CONCLUSION: Excess dissection of carotidoculomotor membranes causes postoperative delayed visual worsening. For treating small, asymptomatic paraclinoid aneurysms, carotidoculomotor membranes should not be opened, and microsurgical clipping should not be performed for preoperative asymptomatic medial projecting aneurysms.

Surgical microanatomy of the occipital artery for suboccipital muscle dissection and intracranial artery reconstruction.

BACKGROUND: The occipital artery (OA) is an important donor artery for posterior fossa revascularization. Harvesting the OA is difficult in comparison to the superficial temporal artery because the OA runs between suboccipital muscles. Anatomical knowledge of the suboccipital muscles and OA is essential for harvesting the OA during elevation of the splenius capitis muscle (SPL) for reconstruction of the posterior inferior cerebellar artery. We analyzed the running pattern of the OA and its anatomic variations using preoperative and intraoperative findings. METHODS: From April 2012 to March 2018, we surgically treated 162 patients with suboccipital muscle dissection by OA dissection using the lateral suboccipital approach. The running pattern and relationship between the suboccipital muscles and OA were retrospectively analyzed using the operation video and preoperative enhanced computed tomography (CT) images. The anatomic variation in the running pattern of the OA was classified into two types: lateral type, running lateral to the muscle and medial type, running medial to the longissimus capitis muscle (LNG). RESULTS: The medial pattern was observed in 107 (66%) patients and the lateral pattern in 54 (33.3%); 1 (0.6%) patient had the OA running between the LNGs. CONCLUSION: Preoperative CT is effective in determining the running course of the OA, which is important for safely harvesting the OA during SPL elevation. There is a risk of causing OA injury in patients with the lateral pattern. This is the first report showing that the OA rarely runs in between the LNGs.

Comprehensive analysis of perforator territory infarction on postoperative diffusion-weighted imaging in patients with surgically treated unruptured intracranial saccular aneurysms.

OBJECTIVE: Perforator territory infarction (PTI) is still a major problem needing to be solved to achieve good outcomes in aneurysm surgery. However, details and risk factors of PTI diagnosed on postoperative MRI remain unknown. The authors aimed to investigate the details of PTI on postoperative diffusion-weighted imaging (DWI) in patients with surgically treated unruptured intracranial saccular aneurysms (UISAs). METHODS: The data of 848 patients with 1047 UISAs were retrospectively evaluated. PTI was diagnosed on DWI, which was performed the day after aneurysm surgery. Clinical and radiological characteristics were compared between UISAs with and without PTI. Poor outcome was defined as an increase in 1 or more modified Rankin Scale scores at 12 months after aneurysm surgery. RESULTS: Postoperative DWI was performed in all cases, and it revealed PTI in 56 UISA cases (5.3%). Forty-three PTIs occurred without direct injury and occlusion of perforators (43 of 56, 77%). Poor outcome was more frequently observed in the PTI group (17 of 56, 30%) than the non-PTI group (57 of 1047, 5.4%) (p < 0.0001). Thalamotuberal arteries (p < 0.01), lateral striate arteries (p < 0.01), Heubner's artery (p < 0.01), anterior median commissural artery (p < 0.05), terminal internal carotid artery perforators (p < 0 0.01), and basilar artery perforator (p < 0 0.01) infarctions were related to poor outcome by adjusted residual analysis. On multivariate analysis, statin use (OR 10, 95% CI, 3.3-31; p < 0.0001), specific aneurysm locations (posterior communicating artery [OR 4.1, 95% CI 2.1-8.1; p < 0.0001] and basilar artery [OR 3.1, 95% CI 1.1-8.9; p = 0.031]), larger aneurysm size (OR 1.1, 95% CI 1.1-1.2; p = 0.043), and permanent decrease of motor evoked potential (OR 38, 95% CI 3.1-468; p = 0.0045) were related to PTI. CONCLUSIONS: Despite efforts to avoid PTI, it occurred even without direct injury, occlusion of perforators, or evoked potential abnormality. Therefore, surgical treatment of UISAs, especially with the aforementioned risk factors of PTI, should be more carefully considered. The evaluation of PTI in the territory of the above-mentioned perforators could be useful in helping predict the clinical course in patients after aneurysm surgery.

Thick Clot in the Inferior Limiting Sulcus on Computed Tomography Image as an Indicator of Sylvian Subpial Hematoma in Patients with Aneurysmal Subarachnoid Hemorrhage.

OBJECTIVE: Sylvian subpial hematoma (SSH) is occasionally observed in aneurysm subarachnoid hemorrhage (aSAH) when accompanied with the thick clot in the inferior limiting sulcus (ILS). We aimed to determine whether the thickness of the clot in the ILS (TCILS) was an indicator of SSH. METHODS: Data from 150 consecutive patients with aSAH were retrospectively analyzed. The relationship between TCILS on axial computed tomography (CT) image and intraoperatively confirmed SSH was reviewed. In patients without SSH, the average of the clot thickness in the bilateral ILS was used. The primary outcome was SSH. RESULTS: The median TCILS of the SSH group (n = 18, 12%) was larger than that of the non-SSH group (n = 132, 88%) (21 vs. 2.1 mm, respectively; P < 0.001). The intraclass correlation coefficients for clot thickness in the right and left ILS between 2 observers were 0.97 (P < 0.001) and 0.85 (P < 0.001). The TCILS threshold of ≥6.0 mm was associated with SSH, with a sensitivity of 89% and specificity of 99%. The unadjusted and adjusted odds ratios of the SSH of clot thickness in the affected ILS ≥6 mm relative to clot thickness in the affected ILS <6 mm were 263 (95% confidence interval [CI], 46-5063) and 137 (95% CI, 19-3029), respectively. CONCLUSIONS: The clot thickness in the ILS on CT image was easily measured and could be a marker of SSH. SSH assessment could be useful in helping us predict the clinical course in patients with aSAH.

Preoperative Predictors and Prognosticators After Microsurgical Clipping of Poor-Grade Subarachnoid Hemorrhage: A Retrospective Study.

BACKGROUND: Contrary to expectations, some patients with poor-grade subarachnoid hemorrhage (SAH) show favorable outcomes. However, the factors predictive of good prognosis are unclear. The purposes of this study were to identify factors related to poor-grade SAH and to analyze preoperative prognostic factors. METHODS: We included 186 patients with SAH who underwent surgical clipping or conservative treatment immediately after SAH diagnosis. Physiologic, radiographic, and blood examination data were collected retrospectively. Factors related to poor World Federation of Neurological Societies (WFNS) grade (WFNS IV and V) and poor outcome (modified Rankin Scale scores 3-6) were analyzed. RESULTS: The patients (mean age, 61.6 years) included 134 women (72%). Seventy patients (38.2%) had poor WFNS scores. On multivariate analysis, age ≥70 years (adjusted odds ratio [OR], 3.73), midline shift (OR, 4.89), and the absence of cerebrospinal fluid in the high-convexity cortical sulci (OR, 5.47) and ambient cistern (OR, 4.83) were predictive of poor WFNS scores. Age ≥70 years (OR, 8.36), WFNS grade 5 (OR, 15.35), intracerebral hematoma (OR, 3.32), and Evans index (EI) ≥0.3 (OR, 4.40) were predictive of poor outcome. Body mass index (OR, 0.87), intraventricular hemorrhage (OR, 3.86), glycated hemoglobin level (OR, 2.78), and age ≥70 years (OR, 4.12) were predictive of EI ≥0.3. CONCLUSIONS: Poor outcomes correlated with older age, brain-destructive hemorrhage, and EI ≥0.3. The EI reflects both hydrocephalus and the patient's frailty. Radiographic signs of poor-grade SAH were not correlated with poor outcome, suggesting that early decompressive surgery may improve outcome.

Analysis for risk factors of 12-month neurological worsening in patients with surgically treated small-to-moderate size unruptured intracranial aneurysms.

The risk associated with surgical treatment for small-to-moderate size unruptured intracranial aneurysms (SMUIAs, defined as <15 mm) has not been well characterized. Authors aimed to investigate risk factors for poor outcome in surgical treatment of SMUIAs. The data of prospectively collected 801 consecutive patients harboring 971 surgically treated SMUIAs was evaluated. Neurological worsening (NW) was defined as an increase in 1 or more modified Rankin Scale at 12-month. Clinical and radiological characteristics were compared. Neurological worsening was observed in 45 (4.6%). In multivariate analysis, only perforator territory infarction (PTI) on postoperative diffusion-weighted imaging (odds ratio (OR), 13; 95% confidence interval (CI), 4.9-32, p < 0.0001), and aneurysm locations (paraclinoid (OR, 6.9; 95% CI, 3.1-15, p < 0.0001), basilar artery (OR, 4.5; 95% CI, 1.5-14, p = 0.008), vertebral artery (OR, 11; 95% CI, 3.3-34, p < 0.0001)) were related to neurological worsening. Multivariate analysis showed that statin use (OR, 12; 95% CI, 3.8-39, p < 0.0001) and aneurysm locations (internal carotid artery-posterior communicating artery (OR, 3.9; 95% CI, 1.8-8.2, p < 0.0001) and basilar artery (OR, 6.3; 95% CI, 2.3-17, p = 0.008)), and aneurysm size >10 mm (OR, 5.3; 95% CI, 1.8-15, p = 0.003) were related to PTI. Although all SMUIAs should be carefully considered whether to be treated, those with statins, specific locations, and larger sizes should perhaps be more meticulously contemplated, and neurosurgeons should continue to avoid PTI.

Morphological parameters as factors of 12-month neurological worsening in surgical treatment of patients with unruptured saccular intracranial aneurysms: importance of size ratio.

OBJECTIVE: It is well known that larger aneurysm size is a risk factor for poor outcome after surgical treatment of unruptured saccular intracranial aneurysms (USIAs). However, the authors have occasionally observed poor outcome in the surgical treatment of small USIAs and hypothesized that size ratio has a negative impact on outcome. The aim of this paper was to investigate the influence of size ratio on outcome in the surgical treatment of USIAs. METHODS: Prospectively collected clinical and radiological data of 683 consecutive patients harboring 683 surgically treated USIAs were evaluated. Dome-to-neck ratio was defined as the ratio of the maximum width of the aneurysm to the average neck diameter. The aspect ratio was defined as the ratio of the maximum perpendicular height of the aneurysm to the average neck diameter of the aneurysm. The size ratio was calculated by dividing the maximum aneurysm diameter (height or width, mm) by the average parent artery diameter (mm). Neurological worsening was defined as an increase in modified Rankin Scale score of 1 or more points at 12 months. Clinical and radiological variables were compared between patients with and without neurological worsening. RESULTS: The median patient age was 64 years (IQR 56-71 years), and 528 (77%) patients were female. The median maximum size, dome-to-neck ratio, aspect ratio, and size ratio were 4.7 mm (IQR 3.6-6.7 mm), 1.2 (IQR 1.0-1.4), 1.0 (IQR 0.76-1.3), and 1.9 (IQR 1.4-2.8), respectively. The size ratio was significantly correlated with maximum size (r = 0.83, p < 0.0001), dome-to-neck ratio (r = 0.69, p < 0.0001), and aspect ratio (r = 0.74, p < 0.0001). Multivariate logistic regression analysis showed that the specific USIA location (paraclinoid segment of the internal carotid artery: OR 6.2, 95% CI 2.6-15, p < 0.0001; and basilar artery: OR 8.4, 95% CI 2.8-25, p < 0.0001), size ratio (OR 1.3, 95% CI 1.1-1.6, p = 0.021), and postoperative ischemic lesion (OR 9.4, 95% CI 4.4-19, p < 0.0001) were associated with neurological worsening (n = 52, 7.6%), and other characteristics showed no significant differences. CONCLUSIONS: The present study showed that size ratio, and not other morphological parameters, was a risk factor for 12-month neurological worsening in surgically treated patients with USIAs. The size ratio should be further studied in a large, prospective observational cohort to predict neurological worsening in the surgical treatment of USIAs.

Surgical Treatment of Middle Cerebral Artery Aneurysms: Aneurysm Location and Size Ratio as Risk Factors for Neurologic Worsening and Ischemic Complications.

BACKGROUND: Regardless of acceptable surgical results of middle cerebral artery aneurysms (MCAs), MCA territory infarction (MCATI) remains a major obstacle to achieving a good outcome. We investigated the MCATI in patients with surgically treated MCA aneurysms. METHODS: The data of 286 consecutive patients with 322 MCA aneurysms were evaluated retrospectively. The aneurysm location was classified as early frontal cortical branch (EFCB), early temporal cortical branch (ETCB), bifurcation or trifurcation (M1-2), and distal aneurysms on the insular, opercular, or cortical segments of the MCA (distal MCA). Neurologic worsening was defined as an increase in 1 or more modified Rankin Scale (mRS) scores. RESULTS: Multivariate analysis identified EFCB location as the sole risk factor for MCATI (odds ratio [OR], 3.8; 95% confidence interval [CI], 1.2-12; P = 0.021) and MCATI (OR, 18; 95% CI, 2.8-117; P = 0.002) and a larger size ratio (OR, 1.4; 95% CI, 1.1-1.8; P = 0.019) were related to 12-month neurologic worsening (n = 6; 1.9%). During follow-up (median, 885 days; interquartile range, 485-1229 days), posttreatment rupture and aneurysm recurrence were not observed. CONCLUSIONS: In the present study, compared with M1-2 aneurysms, MCATIs were observed more frequently in EFCB aneurysms, and the presence of MCATI and a larger size ratio were related to 12-month neurologic worsening in patients with surgically treated MCA aneurysms.

Evaluation of Microsurgery for Managing Giant or Complex Cerebral Aneurysms: A Retrospective Study.

OBJECTIVE: Surgical or endovascular treatment for giant or complex aneurysms is challenging. The aims of this study were to evaluate clinical outcomes and factors affecting the prognosis of giant or complex aneurysms and to better establish the role of microsurgery in the management strategy. METHODS: One hundred fifty-nine patients with surgically treated complex aneurysms were included. Thirty-two patients (20.1%) had giant aneurysms (≥25 mm) and 57 (35.8%) had large aneurysms (≥15 mm). Poor outcome was defined as modified Rankin Scale scores of 3-6. RESULTS: The mean aneurysm size was 17.0 mm (range, 1.6-47.5 mm). One hundred and sixteen aneurysms (80.0%) were in the anterior circulation and 43 (27.0%) were in the posterior circulation. One hundred and thirty-eight (86.8%) aneurysms were completely occluded without residual aneurysms. Nineteen (11.9%) had minor aneurysm remnants; 2 (1.3%) had incomplete occlusion. Two patients (1.3%) with giant basilar artery (BA) trunk aneurysms experienced rupture of the treated aneurysm and died. Bypass surgery was combined with microsurgery in 148 patients (93.1%). Perforating artery infarction was observed postoperatively in 42 patients (26.4%), and poor outcome was observed in 29 (18.2%). Male sex (P = 0.016; adjusted odds ratio [OR], 4.524 [1.949-10.500]), perforating artery infarction (P < 0.001; adjusted OR, 13.625 [5.329-34.837]), and BA aneurysm location (P = 0.003; adjusted OR, 56.333 [6.830-464.657]) were significantly related to poor outcome. The aneurysm size (P = 0.017; adjusted OR, 1.064 [1.021-1.107]), C1 aneurysm location (P = 0.042; adjusted OR, 2.591 [0.986-6.811]), and BA aneurysm location (P = 0.033; adjusted OR, 12.956 [3.197-52.505]) were significantly related to perforating artery infarction. CONCLUSIONS: Microsurgery with bypass is effective for many different complex aneurysms, except BA aneurysms.

Impacts of a Size Ratio on Outcome in Patients with Surgically Treated Unruptured Nondissecting Anterior Cerebral Artery Aneurysms.

BACKGROUND: Anterior cerebral artery aneurysms (ACAs) are characterized by higher rupture rate and small size at rupture. It was shown that the aneurysm/vessel size ratio, and not the absolute size, might predict the risk of rupture in small unruptured intracranial aneurysms. The present study aimed to investigate the relationship between a size ratio and outcome in patients with unruptured nondissecting ACA aneurysms (UNDAs). METHODS: A total of 187 consecutive patients with 12 A1 (6.2%), 149 anterior communicating artery (77%), and 33 distal ACA (17%) aneurysms were retrospectively evaluated. The size ratio was defined as (size of aneurysm)/(size of parent artery). Neurologic worsening (NW) was defined as an increase in score of 1 or more on the modified Rankin Scale (mRS). RESULTS: The mean age of the patient population was 63 ± 11 years and 132 UNDAs (68%) were seen in women. Complete, partial neck clipping, and aneurysm trapping were archived in 188 (97%), 2 (1.0%), and 4 (2.1%) UNDAs, respectively. An excellent outcome (mRS score 0) at 12 months was archived in 177 (93%) UNDAs overall and 177 (95%) in UNDAs with preoperative mRS score of 0 (n = 186). Postoperative ischemic lesions (odds ratio, 193; 95% confidence interval, 17-2205; P < 0.0001) and the size ratio >3.0 (odds ratio, 11; 95% confidence interval, 1.2-105; P = 0.031) were related to 12-month NW on multivariate analysis. The aneurysm size was not related to 12-month NW. CONCLUSIONS: The present study showed that the size ratio, and not the absolute size, was related to 12-month NW in surgically treated UNDAs.

Subarachnoid hemorrhage after surgical treatment of unruptured intracranial aneurysms.

OBJECTIVE Only a few previous studies have investigated subarachnoid hemorrhage (SAH) after surgical treatment in patients with unruptured intracranial aneurysms (UIAs). Given the improvement in long-term outcomes of embolization, more extensive data are needed concerning the true rupture rates after microsurgery in order to provide reliable information for treatment decisions. The purpose of this study was to investigate the incidence of and risk factors for postoperative SAH in patients with surgically treated UIAs. METHODS Data from 702 consecutive patients harboring 852 surgically treated UIAs were evaluated. Surgical treatments included neck clipping (complete or incomplete), coating/wrapping, trapping, proximal occlusion, and bypass surgery. Clippable UIAs were defined as UIAs treated by complete neck clipping. The annual incidence of postoperative SAH and risk factors for SAH were studied using Kaplan-Meier survival analysis and Cox proportional hazards regression models. RESULTS The patients' median age was 64 years (interquartile range [IQR] 56-71 years). Of 852 UIAs, 767 were clippable and 85 were not. The mean duration of follow-up was 731 days (SD 380 days). During 1708 aneurysm years, there were 4 episodes of SAH, giving an overall average annual incidence rate of 0.23% (95% CI 0.12%-0.59%) and an average annual incidence rate of 0.065% (95% CI 0.0017%-0.37%) for clippable UIAs (1 episode of SAH, 1552 aneurysm-years). Basilar artery location (adjusted hazard ratio [HR] 23, 95% CI 2.0-255, p = 0.0012) and unclippable UIA status (adjusted HR 15, 95% CI 1.1-215, p = 0.046) were significantly related to postoperative SAH. An excellent outcome (modified Rankin Scale score of 0 or 1) was achieved in 816 (95.7%) of 852 cases overall and in 748 (98%) of 767 clippable UIAs at 12 months. CONCLUSIONS In this large case series, microsurgical treatment of UIAs was found to be safe and effective. Aneurysm location and unclippable morphologies were related to postoperative SAH in patients with surgically treated UIAs.

Posterior Inferior Cerebellar Artery Thrombosed Aneurysm Associated with Persistent Primitive Hypoglossal Artery Successfully Treated with Condylar Fossa Approach.

A 68-year-old woman presented with generalized seizure due to the left internal carotid artery (ICA) aneurysmal compression of the ipsilateral medial temporal lobe. Computed tomography angiography (CTA) revealed multiple aneurysms of the right persistent primitive hypoglossal artery (PPHA), the right ICA, and the right anterior cerebral artery (ACA). The right PPHA originated from the ICA at the level of the C1 and C2 vertebral bodies and passed through the hypoglossal canal (HC). The PPHA aneurysm was large and thrombosed, which was located at the bifurcation of the right PPHA and the right posterior inferior cerebellar artery (PICA), projecting medially to compress the medulla oblongata. Since this patient had no neurological deficits, sequential imaging studies were performed to follow this lesion, which showed gradual growth of the PPHA aneurysm with further compression of the brain stem. Although the patient remained neurologically intact, considering the growing tendency clipping of the aneurysm was performed. Drilling of the condylar fossa was necessary to expose the proximal portion of the PPHA inside the HC. The key of this surgery was the preoperative imaging studies to fully understand the anatomical structures. The PPHA was fully exposed from the dura to the corner its turning inferiorly without damaging the occipital condylar facet. Utilizing this technique, the neck ligation of the aneurysm was safely achieved without any surgical complications.

Preventing Cerebral Vasospasm After Aneurysmal Subarachnoid Hemorrhage with Aggressive Cisternal Clot Removal and Nicardipine.

BACKGROUND: A subarachnoid clot is the strongest predictor of cerebral vasospasm. Our purpose was to analyze the relationship between the number of postoperative cisternal clots and cerebral vasospasm and to assess the efficacy of surgical clot removal. METHODS: The subjects were 158 patients with aneurysmal subarachnoid hemorrhage. All patients underwent clipping with cisternal clot removal. The preoperative and postoperative number of clots was analyzed semiquantitatively using computed tomography, and cerebral vasospasm and its severity were analyzed using magnetic resonance angiography in a blind fashion. Factors related to cerebral vasospasm and poor outcome were analyzed retrospectively. Poor outcome was defined as modified Rankin Scale (mRS) score of 3 or greater. RESULTS: Symptomatic cerebral vasospasm (SCV) was observed in 6 patients (3.8%). Angiographic vasospasm (AVS) was observed in 38 patients (24.1%). One year after the operation, 82.9% of patients had an mRS score of 0-2. The postoperative number of clots was significantly (P < 0.005) related to SCV (adjusted odds ratio [OR], 6.447; 95% confidence interval [CI], 2.063-20.146), AVS (OR, 2.634; 95% CI, 1.467-4.728), and poor outcome (OR, 2.103; 95% CI, 1.104-4.007). Poor outcome was also related to age over 65 (OR, 6.658; 95% CI, 2.389-18.559) and World Federation of Neurosurgical Societies scale grade (OR, 1.732; 95% CI, 1.248-2.403). CONCLUSIONS: Surgically removing as many clots as possible in the acute stage can decrease SCV and reduce AVS severity. Irrigation should be performed on all approachable cisterns.

The Suzuki-Miyaura Coupling of Nitroarenes.

Synthesis of biaryls via the Suzuki-Miyaura coupling (SMC) reaction using nitroarenes as an electrophilic coupling partners is described. Mechanistic studies have revealed that the catalytic cycle of this reaction is initiated by the cleavage of the aryl-nitro (Ar-NO2) bond by palladium, which represents an unprecedented elemental reaction.

Surgical treatment of unruptured distal basilar artery aneurysm: durability and risk factors for neurological worsening.

BACKGROUND: Distal basilar artery aneurysms (DBAs) consist of basilar apex and basilar artery-superior cerebellar artery bifurcation (BA-SCA) aneurysms. The authors aimed to investigate clinical and radiological differences between two locations and to evaluate the 12-month surgical outcome in unruptured DBAs. METHODS: Fifty-six consecutive patients who underwent surgical treatment (37 basilar apex and 19 BA-SCA aneurysms) between April 2012 and February 2016 were retrospectively evaluated. In patients with a preoperative modified Rankin Scale score (mRS) of more than 1, neurological worsening (NW) was defined as an increase in one or more mRS. In patients without symptoms, NW was defined as mRS ≥2. RESULTS: The mean age of the patient population was 64 ± 9.6 years, and 48 (86%) were female. Mean follow-up period was 2.6 ± 0.94 years. An excellent (mRS 0 to 1) outcome was archived in 31 (55%), 45 (82%), and 48 (87%) patients at 30 days, 6 months, and 12 months, respectively. Clinical and radiological characteristics showed no differences between two locations. One early death (1.8%) and one severe morbidity (1.8%) due to rupture were observed. The postoperative annual rupture rate was 1.4% overall (145 patient-years). After adjustment for age and location, large or giant DBA was related to 30-day and 12-month NW [n = 22 (39%) and n = 6 (11%); p = 0.009 and 0.002, respectively], aneurysm localization in the interpeduncular cistern (LIC) and perforator territory infarction were related to 30-day NW (p = 0.002 and 0.002), and DBA that needed bypass surgery and previously treated recurrent DBA were related to NW at 12 months (p = 0.017 and 0.001). Multivariate analysis showed that LIC was significantly related to perforator territory infarction (p = 0.003). CONCLUSIONS: Clinical and radiological characteristics were not different between basilar apex and BA-SCA aneurysms; therefore, they should not be discussed separately. To avoid neurological worsening, results of surgical treatment for unruptured DBAs should be improved.

Surgical Microanatomy of the Posterior Condylar Emissary Vein and its Anatomical Variations for the Transcondylar Fossa Approach.

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.

Impacts of pressure bonding fixation on a bone flap depression and resorption in patients with craniotomy.

Fixation of bone flaps after craniotomy is a routine part of every neurosurgical procedure. Common problems encountered are bone flap depression and resorption. Authors performed the pressure-bonding bone flap fixation (PBFF) using absorbable craniofix (AC) and hydroxyapatite wedge (HW). The aim of the present study is to evaluate the efficacy of PBFF to prevent a bone flap depression and resorption in patients treated with craniotomy. Four-hundred fifty-four patients underwent craniotomies. Authors collected the following data: age, sex, type of craniotomy, what kind of surgery, whether bypass surgery was performed, whether surgery was the initial, whether AC and the HW were used, bone flap depression and resorption at 6-month after the craniotomy. PBFF was defined as a bone flap fixation using both AC and HW to impress a bone flap to forehead. The mean age was 62±13years and 404 (89%) patients were women. PBFF was performed in 71 patients (16%), either AC or HW was used in 141 (31%), only AC was used in 116 (25%), and only HW was used in 25 (5.5%). At 6-month after the surgery, a bone flap depression was seen in 38 patients (8.4%), and a bone flap resorption was seen in 66 (15%). Multivariate analysis showed that only a PBBF showed a negative correlation with bone flap depression (p=0.044) and resorption (p=0.011). The results of the present study showed that PBFF reduced a bone flap depression and resorption and provided excellent postoperative cosmetic results.

A Contralateral Transcondylar Fossa Approach with Bilateral V3 Segment Exposure for Repairing Complex Vertebral Artery Aneurysms.

BACKGROUND AND IMPORTANCE: Microsurgical treatment for vertebral artery aneurysms can be approached through the lateral aspect of the brainstem and cerebellum. A contralateral approach may be selected in complex aneurysms with tortuous running and the intracranial vertebral artery distal to the aneurysm located in the contralateral cerebellopontine angle. When repairing the aneurysm, exposing the V3 segment before craniotomy is advantageous. We describe the detailed surgical procedures of the contralateral transcondylar fossa approach with bilateral V3 segment exposure for the repair of a complex vertebral artery aneurysm. CLINICAL PRESENTATION: A 48-year-old woman presented with a 23-mm unruptured thrombosed fusiform aneurysm in the right vertebral artery. The aneurysm and the V4 segment distal to it deviated to the left, and the aneurysm was compressing the left anterior aspect of the medulla oblongata. We treated the patient with trapping and thrombectomy, using a contralateral transcondylar fossa approach with bilateral V3 exposure. During the procedure, proximal vascular control was achieved by occluding the contralateral V3 segment and distal control was achieved by occluding the V4 segment. The aneurysm was successfully trapped and decompressed. The patient's postoperative course was good and she was discharged with a modified Rankin Scale score of 0. CONCLUSIONS: The contralateral transcondylar fossa approach with bilateral V3 exposure is feasible for the repair of complex vertebral artery aneurysms showing a deviated and difficult to access V4 segment proximal to the aneurysm. Bilateral V3 exposure may also facilitate aneurysm bypass procedures such as those using a V3-V4 anastomosis.

Bypass Revascularization Applied to the Posterior Cerebral Artery.

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.