Under recognized yet a clinically relevant impact of aneurysm location in Distal Anterior Cerebral Artery (DACA) aneurysms: insights from a contemporary surgical experience.

Aneurysms of the distal anterior cerebral artery (DACA) are rare but surgically challenging. Despite a known therapeutic implication of the aneurysm location on the DACA territory, the literature is unclear about its clinical and prognostic significance. Our surgical experience over the last 5 years was reviewed to compare the clinical, operative, and outcome characteristics between aneurysms located below the mid portion of the genu of the corpus callosum (called proximal aneurysms) to those distal to this point (called distal aneurysms). A prognostic factor analysis was done using uni and multivariable analysis. A total of 34 patients were treated (M: F = 1:2.3). The distal group had a higher frequency of poor clinical grade at presentation (n = 9, 47.4%) in contrast to (n = 2, 13.3%) proximal aneurysms (p = 0.039). Despite an overall tendency for a delayed functional improvement in these patients, the results were mainly due to favorable outcomes in the proximal group (favourable functional outcomes at discharge and at last follow-up being 80% and 86.7% respectively). On the multivariable analysis, only WFNS grade (> 2) at presentation (OR = 13.75; 95CI = 1.2-157.7) (p = 0.035) and application of temporary clips (AOR = 34.32; 95CI = 2.59-454.1) (p = 0.007), both of which were more in the distal group, independently predicted a poor long term functional outcome. Thus, the aneurysm location impacts the preoperative clinical grade, the intraoperative aneurysm rupture risk rate as well as the temporary clipping requirement. A combination of these factors leads to worse short and long-term functional outcomes in the distal DACA aneurysms.

Pediatric Lumbosacral Spondylolisthesis: Overcoming the Disability!

BACKGROUND: Congenital spondylolisthesis is characterized by dysplasia of the facet joint or congenital defect in the pars. OBJECTIVE: Our study highlights the clinical and radiological profile, various treatment options, and outcomes in patients with pediatric congenital lumbar and lumbosacral spondylolisthesis. METHODS: A retrospective analysis and follow-up of 22 patients were conducted presented with radiological diagnosis of congenital lumbar/lumbosacral spondylolisthesis (2018-2021). RESULTS: Twenty patients (91%) had L5-S1 listhesis and two patients (9%) had L4-L5 listhesis. Six (27.3%) patients had low-grade listhesis (grades 1-2), 16 (72.7%) had high-grade listhesis (grades 3-5). Seventeen (77.3%) had S1, three (13.6%) had L5, and two (9%) had both L4-L5 radiculopathy. All patients had neurogenic claudication. One had an associated spina bifida occulta. Six (27.3%) patients underwent two-level fixation, and 16 (72.7%) underwent three-level fixation. Minimally Invasive Transforaminal Lumbar Interbody Fusion (MIS TLIF) was done in two patients. Revision of at least one screw was done in three patients. After one year of follow-up, all the patients had 75-100% relief in radicular pain and neurogenic claudication. The Oswestry Disability Index (ODI) score in preop for all patients was 41-60% and postoperatively they showed an improvement in ODI score (0-20). The postoperative low back pain score on the Numeric Rating Scale was 0-1 for all patients. CONCLUSION: Congenital lumbar spondylolisthesis usually presents with high-grade listhesis. Management of such cases is a surgical challenge but posterior decompression resulted in relief of pain in all patients. However, in situ fixation without reduction is also effective in selective cases where attempts to reduce the listhesis result in a decline in intraoperative neuromonitoring parameters.

Potential and Pitfalls of Postoperative Volumetric Assessment of Extent of Resection in High-Grade Glioma in Resource-Constrained Settings.

BACKGROUND: While literature suggests the need for routine postoperative volumetric estimation of the EOR and residual tumour volume (RTV) in all cases of gliomas, the utility and feasibility of this protocol in resource-constrained centers remain underinvestigated. OBJECTIVES: Our objective was to study the feasibility of volumetric EOR in routine neurosurgical practice and determine correlation with surgeons' intraoperative estimation of EOR. The secondary objective was to determine the survival impact of EOR and RTV on survival. METHODS AND MATERIALS: A prospective study of pathologically proven high-grade gliomas (WHO grades 3 and 4) in adults was conducted at a tertiary care center. Pre- and postoperative magnetic resonance imaging (MRI) was obtained for volumetric analysis using OsiriX software and manual segmentation. Overall survival and predictors were studied using Kaplan-Meier and Cox regression analysis. RESULTS: Postoperative volumetry was feasible in 31% patients (n = 25) of study eligible patients (n = 84). The median EOR, CE-PTV, and CE-RTV were 79.1%, 69.8 cm3, and 8.7 cm3, respectively. There was a poor correlation of surgeons' intraoperative impression and volumetric data (P = 0.359). Interestingly, the EOR was not significantly associated with the survival time (P = 0.920), while tumor grade, molecular profile, Ki 67 score, and postoperative functional status showed statistically significant impact. CONCLUSION: Logistic difficulties impede routine implementation of this protocol in developing countries. MRI volumetry is clearly more accurate than surgeons' intraoperative estimation of EOR. Notwithstanding the role of EOR in survival, our study reveals a perhaps bigger impact of tumor biology and postoperative functional status in this equation.

Outcomes following surgical clipping of re-ruptured previously untreated intracranial aneurysms.

Re-rupture of untreated intracranial aneurysm is a potentially life-threatening condition. Despite tremendous advances in the diagnosis and treatment of intracranial aneurysms, such events are not rare and continue to pose a management dilemma. In this study, we examined the clinical, radiological and treatment details of patients who underwent microsurgical clipping for re-rupture of previously untreated intracranial aneurysms. Re ruptures were categorized as early and late re ruptures (< or > 7 days of inter ictus interval respectively). Modified Rankin Score (mRS) was used for functional outcome assessment and logistic regression analysis was used to test the predictors of long-term outcome. Re-ruptured intracranial aneurysms comprised 5% (n = 32/637) of the aneurysm clippings done at our center in this time span. The mean mRS score at discharge and at last follow-up were 3 and 3.04 respectively. Twenty-four (75%) patients were alive at a mean follow-up of 36 months. Early re-ruptures were associated with worse mean mRS scores at discharge (3.9 vs 2.5, p = 0.03) including the perioperative deaths (n = 4, 12.5%). The functional status at discharge and a poor preoperative clinical grade predicted a poor long-term outcome. Therefore, the long-term outcomes are primarily dependent on the short-term outcomes and to a lesser extent, the clinical grade at presentation. Those presenting with poor preoperative clinical grade, especially in the setting of an early re rupture, have a very poor prognosis and do not benefit from surgery.

Anterior Communicating Artery Aneurysms: Surgical Strategy and Outcome based on Proposed Newer Classification.

BACKGROUND: The ruptured anterior communicating artery aneurysm is the most frequent intra-cranial aneurysm treated at any neurosurgical department. These aneurysms arise from either the A1-A2-Acom artery junction or Acom artery. The surgical outcome depends on the age of the patient, time duration between ictus and surgery, and Hunt and Hess grade at admission. In this article, we intend to analyze the surgical outcome based on our proposed classification with our overall experience of Acom aneurysm. METHODS: A retrospective review of our surgical database with 250 patients of ruptured Acom was done, and the location, morphology, and direction of aneurysm, along with other clinical parameters including the demographic profile, radiological findings, and intra-operative details, were studied. We classified the Acom based on both site of origin and morphology (Type I, junctional on the dominant side; Type II, fusiform with an ill-defined neck and branching pattern; Type III, saccular true Acom A) and secondarily as described in the literature on the basis of the direction of fundus (Type A-E). The clinical parameters were compared among the above groups using Fischer-exact and one-way analysis of variance test. RESULTS: A total of 250 patients (M: F =113:137) were included (mean age 52.1 ± 11.5 standard deviation years). 55.2% patients had left A1 dominance. Type I Acom A was commonly found on the left dominant circulation (P = 0.00). The difference in aspect ratio of Type I (2.0 ± 0.8) and Type II (1.8 ± 0.52) aneurysms was insignificant (P = 0.28). However, a significant difference in post-operative vasospasm among different types of aneurysms was found (P < 0.05). The Type I Acom A were anteriorly directed, while Type II and III were posteriorly directed (P = 0.001). The mean follow-up of the study was 44.4 ± 25.7 months, with age (P = 0.007) and Hunt and Hess grade (P = 0.001) at admission correlating with surgical outcome. CONCLUSION: Classifying the Acom A pre-operatively based on site and morphology, location, and direction of fundus helps in surgical planning and prognosis. The junctional 'Type IA aneurysms' are most common and possess a high intra-operative rupture rate. The anteriorly directed aneurysms have a better prognosis, and visual complaints are usually associated with anterior-inferiorly directed aneurysms.

Trans-temporal trans-choroidal resection of thalamic and thalamopeduncular tumors: how I do it.

BACKGROUND:  Surgical resection is the cornerstone of treatment for low-grade tumors, albeit total excision is beneficial. As the thalamus is surrounded by vital neurovascular system, lesions here present a surgical challenge. METHOD: This article aims to demonstrate the trans-temporal, trans-choroidal fissure approach's effective surgical therapy on patients with thalamic lesions. With this approach, we were able to remove the tumor completely in three patients and almost completely in six more. Here we discuss a few technical details and potential hazards of the procedure with an operative video. CONCLUSION: This approach  provides excellent access to the deep areas of brain.

Optimum Surgical Strategies for Medial Sphenoid Wing Meningiomas: A Comprehensive Evaluation of Resection Extent, Visual Outcomes, and Vascular Injury.

BACKGROUND/OBJECTIVE: Visual impairment affects 55%-80% of medial sphenoid wing meningiomas (mSWMs) patients, making optic nerve decompression a critical surgical goal. Complete resection often leads to better visual outcomes. However, involvement of critical neurovascular structures increases postoperative morbidity and mortality, with vascular injury reported in 18%-20% of cases. This study aims to evaluate the relationship between the extent of resection (EOR), visual outcomes, and the incidence of vascular injury, seeking to identify the optimal surgical approach for mSWMs. METHODS: We retrospectively analyzed data from patients undergoing surgery for mSWM at our tertiary care center from January 2001 to December 2021. Inclusion criteria included histopathologically confirmed globoid mSWMs (N = 89). Patients with recurrent tumors (n = 14) or lost to follow-up (n = 9) were excluded. We classified patients into 2 groups based on EOR using Simpson's grade: Group 1 (good-resection,Simpson Grade-I/II,n = 51) and Group 2 (poor-resection,Simpson Grade III/IV, n = 15). RESULTS: Among 66 (=N) patients, visual impairment was the most common symptom (81.8%), followed by headaches (77.3%) and seizures (27%). T2-hyperintensity on magnetic resonance imaging [(OR:5.4, 95%CI:1.5-18.6) (P-value<0.01)] and cavernous sinus-extension [(OR:3.9, 95%CI:1.1-13.1) (p-value-0.02)] were independent significant predictors of poor resection. Visual status was preserved in 90.3% of Group-1 and 86.6% of Group-2, with no significant difference based on EOR. Vascular involvement was noted in 87.9%, higher than the vessel encasement (>1800) (57.6%, P = 0.04). Vessel injury occurred in 7.8% of Group-1 and 6.6% of Group-2, with no significant impact on EOR. CONCLUSIONS: Cavernous sinus-extension and T2-hyperintensity predict poor resection rates in mSWMs. While visual outcomes are not directly affected by EOR, long-term visual status may decline due to tumor recurrence and radiotherapy. Vascular injury incidence is not associated with EOR. Thus, the "maximal safe resection" of mSWMs involves a surgical strategy balancing targeted aggressive and conservative resection for maximal cytoreduction and functional preservation.

Clipping of Kissing Distal Anterior Cerebral Artery Aneurysms: The Importance of Microsurgical Techniques to Enlarge the Surgical Corridor and Prevent a Premature Aneurysm Rupture.

Intracranial kissing aneurysms, arising either from the same artery or from 2 adjacent arteries at similar locations, are rare.1,2 The internal carotid artery is most frequently involved; kissing aneurysms rarely affect the distal anterior cerebral artery (DACA). By dint of the close proximity of the aneurysm fundus, these aneurysms can pose unique operative challenges.3,4 A highly fragile aneurysm dome with a high intraoperative rupture rate is a unique management challenge in DACA aneurysms.5 The stakes are higher when there is an aneurysm rupture in the setting of kissing DACA aneurysms requiring an anterior interhemispheric approach. The negotiation of a tight interhemispheric fissure in between the bridging veins and prevention of a premature aneurysm rupture at a narrow space become vital in these situations. Video 1 highlights the surgical steps of clipping bilateral kissing DACA aneurysms in a 60-year-old woman. This surgical video highlights the microneurosurgical nuances of opening a tense interhemispheric fissure and maneuvers for prevention of a premature aneurysm rupture. These nuances are quintessential in the successful surgical clipping of kissing DACA aneurysms. The patient in Video 1 presented with an acute subarachnoid hemorrhage with severe headache of sudden onset and nuchal rigidity (World Federation of Neurological Surgeons grade II). Both aneurysms were located at the A3-A4 junction and successfully clipped through a right-sided anterior interhemispheric approach. She made a satisfactory postoperative recovery (modified Rankin Scale score of 1 at 6-week follow-up and 0 at 6-month follow-up) with an excellent angiographic outcome.

Anterior clinoidectomy in low lying internal carotid artery-posterior communicating artery aneurysm.

BACKGROUND: At times, a regulation internal carotid artery-posterior communicating artery junction (ICA-P-Comm) aneurysm becomes a surgical hurdle owing to its close proximity to the anterior clinoid process, an immovable ICA and a concealed dominant P-Comm artery arising from the aneurysm neck. METHOD: A 70 year old patient with a low lying ICA-P-Comm aneurysm underwent a "tailored" intradural clinoidectomy for aneurysm clipping. CONCLUSION: A tailored anterior clinoidectomy to expose "just enough" allows a proximal ICA control in a suitable area, mobility of an atherosclerotic ICA and exposes the P-Comm artery origin which are essential in safe clipping of these aneurysms.

Occipital encephalocele: a retrospective analysis and assessment of post-surgical neurodevelopmental outcome.

BACKGROUND: Encephalocele represent a group of disorders which is characterised by extracranial herniation of the leptomeninges, brain, and CSF through a structural defect in the cranium. They are usually associated with other intracranial anomalies which may impact the neurological development. AIM: This study aimed to assess the predictors of neurological development of patients undergone surgical excision of occipital encephalocele. METHODS: All patients with occipital encephaloceles operated over the last decade (2012-2022). The sac size, presence of hydrocephalous, and associated anomalies were noted. The biopsy of these patients were reviewed and categorised as those which contains mature neural tissue and those without. The neurological outcomes were assessed by social, language, cognitive, and motor milestone and has been stratified into no delay, mild (1 of 4), moderate (2 or 3 of 4), and severe development delay (4 of 4). RESULTS: Total of 35 patients were included with median age of 10 months (IQR = 5-20 months). Fifteen (42.9%) patients had sac size of ≥ 5 cm, and 23 (65.7%) patients had mature neural tissues on biopsy. The median follow-up period was 6.4 years (IQR = 4.38-10.65) years. Seventeen (49.6%) patients had moderate to severe developmental delay. The sac size of ≥ 5 cm (AOR = 33.5; 95%CI = 3.35-334.8) (p = 0.003) and presence of mature neural content in the sac (AOR = 13.32; 95%CI = 1.1-160.36) (p = 0.041) were associated with significant neurodevelopmental delay. CONCLUSION: The presence of a large sac of ≥ 5 cm and the presence of mature neural tissues on histopathological specimen of patients with encephalocele point towards the possibility of poor neurological development.

An institutional study on accuracy of freehand cervical C1 C2 screws placement by knock and drill technique in craniovertebral anomalous bony anatomy: An evaluation of more than 600 screws based on SGPGI screw accuracy criteria.

Purpose: To assess the accuracy of freehand cervical C1 C2 screws placement by knock and drill (K and D) technique in craniovertebral anomalous bony anatomy. Materials and Methods: From January 2017 to December 2022, 682 consecutive C1 C2 screws in 215 patients with craniovertebral junction (CVJ) anomalies were enrolled. All patients underwent posterior fixation with K and D technique without any fluoroscopic guidance. The patient's demographic details, clinical details, radiological details, major intraoperative events, and postoperative complications were noted. The screws malposition grades and direction on CT images in the axial and sagittal plane were defined as new per proposed "SGPGI accuracy criteria." All patients had a clinical evaluation at 3-month follow-up. Results: Total 682 C1, C2 screws were placed in 215 patients for CVJ anomalies using K and D technique. The accuracy of screws placement by freehand technique was 84.46% (576/682). So with technique explained the rate of malplacement in simple (16.35%) and complex (15.19%) groups were almost comparable and comparison difference was not significant (P = 0.7005). Conclusion: The freehand technique, as described, is effective in cases of anomalous bony anatomy, and it is mandatory in complex CVJ anomalies. The accuracy of screw placement and VA injury is comparable with major studies. This technique is supposedly cost-effective and less hazardous to both health-care workers and patients.

Endoscopic MIS-TLIF with Destandau's system: leveraging endoscopy with conventional instruments.

This presentation showcases an endoscopic minimally invasive spine surgery (MISS) technique for lumbar interbody fusion. Significantly expanding the scope of Destandau's system within MISS, it serves as a pivotal link to unilateral biportal endoscopy (UBE) for endofusion. The method involves minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) using a 4-mm rigid endoscope through Destandau's system. With the widespread familiarity with Destandau's system and the absence of specialized instrument requirements, this approach is easily adoptable, particularly in resource-limited centers. The favorable clinical and radiological outcomes underscore the effectiveness of this technique, propelling the role of endoscopy in MISS, particularly in endofusion. The video can be found here: https://stream.cadmore.media/r10.3171/2024.1.FOCVID23216.

Comparative analysis of supra-orbital keyhole approach and pterional approach for surgical clipping of intracranial anterior circulation aneurysms in patients with favorable Hunt and Hess grades.

INTRODUCTION: Traditional large craniotomies have been the standard for aneurysm surgery. However, minimally invasive "keyhole" approaches have gained popularity for aneurysm clipping in recent years. This study focuses on Supra-Orbital Keyhole Approach (SOKHA),its use in clipping of aneurysms of the anterior Circle of Willis. Here we share the experiences of a tertiary care center regarding aneurysm clipping using SOKHA. MATERIALS AND METHODS: We retrospectively reviewed 166 cases involving aneurysm clipping, with 62 patients undergoing SOKHA and 104 patients undergoing the pterional approach. Factors evaluated included patient demographics, aneurysm characteristics, incidence of intraoperative complications, temporary-clipping usage, and postoperative clinical outcomes. Glasgow Outcome Scale scores were utilized to assess clinical outcomes. RESULTS: The study found that both the SOKHA and pterional approaches were similar in terms of age distribution, Hunt and Hess grades, and the incidence of hydrocephalus. The majority of aneurysms in both groups were anterior communicating artery aneurysms.Hydrocephalus was observed in 14.5 % of SOKHA cases and 13.5 % of pterional cases. Intraoperative aneurysm rupture occurred in 8.1 % of SOKHA cases and 7.7 % of pterional cases. There were no mortalities in the SOKHA group, while the pterional group had 1.92 % mortality rate. At the last follow-up, 77.4 % of SOKHA cases and 75.9 % of pterional cases had a favorable outcome (Glasgow Outcome Scale IV and V), with no significant difference. CONCLUSION: SOKHA offers the advantage of potential cosmetic benefit with neurological outcomes comparable to those of the traditional pterional approach, in properly selected patients.

Stereotactic biopsy for brain lesions: Doing more with less.

Objectives: Stereotactic biopsy (STB) is a potential diagnostic tool considering its minimal invasiveness, high diagnostic yield, and minimal associated complications. Over the years, various frame-based instrument systems and frameless stereotactic biopsy systems have emerged to be employed in clinical use. With this study, we intend to get more by doing less in the form of STB for the patients of doubtful intracranial lesions treated over the past 5 years. We also want to highlight the technique of performing the procedure under scalp block, which can be used as a versatile tool in many clinical scenarios. Stereotactic biopsies may be planned even in rural district-level health facilities. One-time investment to procure instruments and avail existing imaging can lead to establishing definitive diagnoses in many doubtful cases. This will result in lesser cost and early establishment of treatment. Independent risk factors determining the outcome, such as deep-seated lesions, associated edema, and intraoperative hypertension, were studied. Establishing the diagnosis helped in prognosticating the disease, explaining the natural progression of symptoms, and starting adjuvant therapy. This tissue biopsy would also help secure samples for research and molecular analysis. Materials and Methods: Twenty patients underwent STBs at our institution between January 2018 and December 2022. We retrospectively analyzed patient characteristics, tumor pathology, surgical procedures, and outcomes, including the diagnostic value and surgery-related complications. These patients were followed up, and their progression-free and overall survival were analyzed. The need for adjuvant treatment was noted and analyzed. All procedures were performed using Cosman Roberts Wells® stereotactic frame. Pre-procedure magnetic resonance scans were performed at the time of admission. Contrast-enhanced computerized tomography (CT) scan after frame application was performed to identify targets and calculate the coordinates. A post-procedure CT scan was done to confirm the accessibility of the targeted lesion. Results: The most common location of the tumor was a deep-seated thalamic lesion. A definitive diagnosis was established in 19 patients (95%) at the first STB. The diagnoses were glioma in 55% of cases, primary central nervous system lymphoma, tuberculosis, and demyelinating disorders in 10% of each, and a metastatic brain tumor in 1 (5%). The post-operative complications were all transient except in one patient with deterioration of motor weakness. The follow-up was noted, and modes of adjuvant treatment needed in these patients were recorded. Conclusion: Stereotactic biopsy is a useful and effective method for achieving a definitive diagnosis and aiding in treating multifocal or small deep-seated lesions in or around eloquent regions.

Clip Reconstruction of Fusiform A1 Segment Aneurysm Using Lateral Supraorbital Approach.

Fusiform aneurysms of the anterior cerebral artery are a surgical rarity encountered only occasionally by a neurosurgeon.1,2 Seen most commonly in the vertebrobasilar territory, these aneurysms differ in pathophysiology and clinical presentation from their saccular counterparts. Arterial dissections and atherosclerosis are the leading causes of these aneurysms in young and elderly patients, respectively.3 Patients can present with symptoms related to mass effect/compression of adjacent structures or with ischemic symptoms apart from aneurysm rupture. Management of these aneurysms remains challenging owing to the lack of a distinct neck. Surgical options include clip reconstruction, parent vessel occlusion, or aneurysm trapping with4 and without1 bypass using a branch of the superficial temporal artery. Clipping techniques used for these aneurysms include the use of fenestrated clips, vessel wall reconstruction, and wrapping.5,6 However, due to enormous variations in aneurysm morphology, each case presents a unique challenge; hence neurosurgeons need to be aware of this important entity. Endovascular techniques including parent vessel occlusion or vessel-preserving techniques using coil or flow diverters have also been described,3 but clipping remains the preferred choice for most surgeons worldwide. In Video 1, we present a case of fusiform A1 segment aneurysm in a 34-year-old gentleman and demonstrate how the aneurysm was clipped using a lateral supraorbital approach. He made an uneventful recovery with subtle right lower limb weakness. This video shows the technique and utility of a minimally invasive skull base approach for dealing with a fusiform anterior circulation aneurysm.

Contribution of Deep Cerebral Venous Anomaly to the Emergence of Nonaneurysmal Subarachnoid Hemorrhage as Opposed to Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND: The exact reason of nonaneurysmal subarachnoid hemorrhage (SAH) is an enigma. The aim of this study is to identify if type III deep cerebral venous drainage is exclusively prevalent in patients with nonaneurysmal SAH and to enumerate the predictors of poorer outcome in these patients. METHODS: All patients of age >18 years, presented at our centre with spontaneous SAH on noncontrast computed tomography head and were divided into 2 groups, aneurysmal and nonaneurysmal SAH after 4-vessel DSA. Based on the deep venous drainage pattern on both sides, basal venous drainage was found and classified into 3 types: type I, type II, and type III. The 3 groups were pitted against one another. Regression analysis were performed to predict the occurrence of nonaneurysmal-SAH with different types of basal vein. RESULTS: There were 100 nonaneurysmal SAH cases and 103 aneurysmal SAH cases. The mean age of presentation was 47.8 ± 13.55 years with slight male predominance (52%). The patients with type III venous drainage have 2 times more risk of developing nonaneurysmal SAH (95% confidence interval = 1.21-4.31) as compared to those with aneurysmal SAH. On multivariate analysis, type III basal venous drainage, worse Hunt and Hess grade at presentation, extensive bleeding were predictors of an adverse outcome. CONCLUSIONS: The presence of type III venous distribution is associated with a 2-fold increase in the probability of having nonaneurysmal SAH, as well as a 3-fold increase in the risk of developing poorer neurological sequelae.