State-of-art in surgical treatment of dissecting posterior circulation intracranial aneurysms.

Vertebrobasilar (VB) intracranial dissecting aneurysms (IDAs) pose difficult therapeutic issues and are especially among the most difficult to manage surgically. There are, however, some cases where selective aneurysm obliteration by endovascular approach is impossible or is associated with an unacceptable risk of morbidity. This is particularly true when the aneurysm is dissecting, giant, or has a large neck. In such cases, surgical treatment may be the only alternative. Optimal management of these lesions is therefore challenging and treatment decisions have to be made on a case-by-case basis. Ideal treatment should be a complete surgical excision of the lesion; however, this procedure might only be possible after distal and proximal vessel wall occlusion which might not be tolerated by the patient depending on the location of the aneurysm. Therefore, formulation of recommendations concerning the surgical strategy remains still difficult due to inconsistency of surgical outcomes. The literature describing surgical strategy of VB IDAs is varying in quality and content, and many studies deal with only a few patients. In the presented review, the authors summarize the current knowledge on the incidence, pathogenesis, clinical presentation, and diagnostic procedures with special emphasis on surgical treatment of IDAs in posterior circulation.

Significance of Pupillary Findings in Decision Making and Outcomes of World Federation of Neurological Societies Grade V Subarachnoid Hemorrhage.

BACKGROUND: There is considerable debate regarding the definition of grade V subarachnoid hemorrhage (SAH). Recently, the Glasgow Coma Scale-Pupil (GCS-P) score was advocated for assessing traumatic brain injury. OBJECTIVE: To study the significance of pupillary findings and GCS-P in the management and outcomes of the World Federation of Neurological Societies (WFNS) grade V SAH. METHODS: We analyzed data obtained from a Japanese nationwide prospective registration study on the modified WFNS SAH grading system. Bilateral pupillary dilatation without reactivity was defined as pupil score 2, unilateral pupil dilation without reactivity as score 1, and no pupil dilatation with reactivity as score 0. The GCS-P score was calculated by subtracting the pupil score from the total GCS score. The characteristics and pupillary findings were examined in patients with each GCS score in WFNS grade V. RESULTS: Among 1638 patients, 472 (men/women = 161/311, age 67.0 ± 14.0 years) had a GCS score of ≤6 after initial resuscitation on arrival. Overall, lower GCS scores were associated with poorer neurological outcomes and higher mortality. Aneurysms were treated in 20.5%, 53.9%, and 67.5% of patients with pupil scores of 2, 1, and 0, respectively. Favorable outcomes (modified Rankin Scale 0-2) at 3 months occurred in 4.5%, 10.8%, and 21.4% in patients with pupil scores 2, 1, and 0, respectively ( P < .0001), and in 0%, 0%, 13.6%, 28.6%, 16.7%, and 18.8% of patients with GCS-P scores 1 to 6 ( P < .0001), respectively. CONCLUSION: Our study confirmed the significance of pupillary findings in decision making and outcomes of WFNS grade V SAH.

Different Risk Factors Between Cerebral Infarction and Symptomatic Cerebral Vasospasm in Patients with Aneurysmal Subarachnoid Hemorrhage.

OBJECTIVE: Cerebral infarction due to cerebral vasospasm (IVS) after aneurysmal subarachnoid hemorrhage is associated with poor outcomes and symptomatic cerebral vasospasm (SVS). However, the difference of risk factors between SVS and IVS was unclear to date. In this study, we aimed to elucidate the risk factors for SVS and IVS based on the registry study. METHODS: The modified World Federation of Neurosurgical Societies scale study comprises 1863 cases. Patients with aneurysmal subarachnoid hemorrhage who underwent radical treatment within 72 hours with a premorbid modified Rankin Scale score 0-2 as the inclusion criteria were retrospectively examined. The risk factors for SVS and IVS were analyzed using multivariable logistic regression analysis. RESULTS: Among them, 1090 patients who met the inclusion criteria were divided into 2 groups according to SVS and IVS; 273 (25%) patients with SVS and 92 (8.4%) with IVS. Age was not a risk factor for SVS, but for IVS, and Fisher scale was a risk factor for SVS, but not for IVS. CONCLUSIONS: The prevalence of IVS was not associated with the Fisher scale but with older age, suggesting possible factors other than SVS. Different associated factors between SVS and IVS were confirmed in this study.

Japanese Subarachnoid Aneurysm Trial of Neurosurgical Clipping versus Endovascular Coiling in 1863 Patients with Ruptured Intracranial Aneurysms.

This is a post hoc multivariate analysis of the modified World Federation of Neurosurgical Societies (WFNS) grading project, multicenter prospective observational study including 38 neurosurgical institutions across Japan. Japan Neurosurgical Society WFNS grading committee conducted a modified WFNS grading project as a nationwide prospective registry study. We investigate the clinical outcome of both surgical and endovascular interventions after aneurysmal subarachnoid hemorrhage (SAH) in Japan. A total of 792 patients received surgical intervention and 417 patients received endovascular treatment. Eight hundred patients were female, and 409 patients were male. The mean age was 61.5 ± 13.7 years. At 3 month follow-up, there was no statistically significant difference in good clinical outcome between surgical (68.2%) and endovascular (60.9%) group (odds ratio, 0.89; 95% confidence interval, 0.68-1.16; p = 0.381). Unfavorable outcome rate was 31.8% (238 patients) in the surgical group and 39.1% (154 patients) in the endovascular group. Male, elderly people, modified Rankin scale condition before onset, high-grade modified WFNS clinical grading scale, intracerebral hematoma, posttreatment normal pressure hydrocephalus, and neurological deficit due to symptomatic vasospasm were risk factors for the clinical outcome. Treatment modality was not a statistical factor for clinical outcomes. Surgical clipping has still a major role in the management of SAH in Japan. The present study was not a randomized controlled study, but clinical outcome is not influenced by treatment modalities.

Changes in Short-Term Outcomes After Discharge in Patients with Aneurysmal Subarachnoid Hemorrhage: A Multicenter, Prospective, Observational Study.

OBJECTIVE: The objective of the study was to clarify the prevalence of and factors associated with changes in patients' outcomes between discharge and 3 months after the onset of aneurysmal subarachnoid hemorrhage (aSAH). Additionally, the World Federation of Neurosurgical Societies (WFNS) and modified WFNS (mWFNS) scales were compared. METHODS: The data of curatively treated patients with aSAH, collected prospectively in the mWFNS scale study between January 2010 and December 2012, were analyzed retrospectively. The improvement or decline in the modified Rankin Scale (mRS) scores between discharge and 3 months after onset was determined. A multivariable logistic regression analysis was performed to identify factors, such as age and WFNS and mWFNS grades, associated with changes in the outcome. RESULTS: The mRS scores improved in 28.3% and declined in 2.5% of the patients. WFNS and mWFNS grades Ⅱ-V on admission were significantly associated with improved mRS scores at 3 months after onset. Older age (age: 65-74 years vs. age <65 years, odds ratio: 6.59, 95% confidence interval: 1.28-34.01; age ≥75 years vs. age <65 years, odds ratio: 17.67, 95% confidence interval: 2.11-148.26) and WFNS grade III were significantly associated with a decline in mRS scores at 3 months after onset. CONCLUSIONS: The optimal timing for postdischarge assessment of outcomes may be at 3 months after onset, especially in older patients with aSAH. The mWFNS scale is presumed to more accurately assess the outcomes of patients with aSAH than the WFNS scale, as demonstrated in this study.

Preliminary evaluation of the role of surgical microscope-integrated intraoperative FLOW 800 colored indocyanine fluorescence angiography in arteriovenous malformation surgery.

OBJECTIVE: To discuss the role of FLOW 800 innovative software for analytical color visualization and objective evaluation of fluorescence videos obtained by microscope-integrated intraoperative indocyanine green (ICG) fluorescence angiography in arteriovenous malformations (AVM) surgery. MATERIALS AND METHODS: Microscope-integrated intraoperative FLOW 800 was used and evaluated in three consecutive AVM surgeries over a period of two months. The role of FLOW 800 to distinguish feeding arteries from arterialized veins and other arteries was evaluated. Its advantages and limitations over conventional intraoperative ICG angiography were evaluated. RESULTS: This software was found to be useful in identifying arterial feeders, arterialized veins and other arteries in all the three patients and it gives additional information on the status of AVM before and after clipping suspected feeders which is sometimes difficult to interpret on conventional ICG angiography. CONCLUSION: Flow 800 is a reliable and useful addition to microscope-integrated color ICG video angiography. Although its role is limited in deep-seated AVMs, if properly dissected and exposed it can give useful information which can be easily interpretable and reproducible.

Delayed surgical resections of brain metastases after gamma knife radiosurgery.

Although brain metastases are one of the most frequently diagnosed sequelae of systemic malignancy, their optimal management still is not well defined. In that respect, the different diagnostic and therapeutic approaches of BMs patients is an issue for serious discussions. The treatment options include surgical excision, WBRT, radiosurgery, chemotherapy, immunotherapy, etc. Nowadays, the aforementioned treatment modalities are usually combined in different treatment schemes. More than one option is used for the same patient and combining these treatment modalities gives better results than when separately use them. The value of surgical excision of progressing brain metastases treated with gamma knife surgery (GKS) is not well investigated.With the present study, we aim to investigate the value of surgical excision of symptomatic brain lesions that have been previously treated with GKS.

Treatment of complex intracranial aneurysms of anterior circulation using multiple clips.

OBJECTIVE: To evaluate the efficacy of multiple clip application for the occlusion of complex intracranial aneurysms, analyzing the technique and outcome of big and giant cerebral aneurysms clipped in our institution. METHOD: A total of 259 giant and large intracranial aneurysms (65 ruptured and 193 unruptured) were treated at Fujita Health University Hospital by clipping from January 1975 till December 2008. All patients were treated by multiple clipping according to our multiple clipping technique with reconstruction of the parent vessel. All patients underwent preoperative 3D computed tomography and some patients in addition received digital subtraction angiography. We examined the patients' clinical records and pre- and postoperative case notes, diagnostic and intraoperative images. There were 97 (giant 43, big 54) ICA aneurysms, 105 (giant 45, big 60) MC aneurysms and 32 (giant 7, big 25) AC aneurysms, 25 (giant 14, big 11) VB aneurysms. All patients underwent thorough pre-surgical planning of approach and clipping technique.Surgical technique involved the use of multiple clips with the initial clip securing the deepest neck part and the others successively occluding the rest by remnant clips, occluding along the best plane of neck obliteration. RESULTS: Out of 193 cases, 165 cases were without any complications. Temporary complications were seen in 18 cases and permanent in 10. In our 65 ruptured aneurysms operated on, outcome was in line with standard outcome according to the SAH grade on admission (H&H, WFNS grade). In total, 183 cases had good results (94.8%). CONCLUSIONS: The "multi" clip method for the treatment of complex intracranial aneurysms can be a safe and effective method where a single clip cannot obtain complete neck closure. Proper preoperative understanding of the three-dimensional anatomy of the aneurysm and appropriate preoperative planning and selection of suitable clipping method, using an appropriate combination of clips, definitely can reduce the morbidity and mortality in these patients.

Risk Factor for Poor Outcome in Elderly Patients with Aneurysmal Subarachnoid Hemorrhage Based on Post Hoc Analysis of the Modified WFNS Scale Study.

OBJECTIVE: There is currently no precise guide for the treatment and management of elderly patients with aneurysmal subarachnoid hemorrhage (aSAH). Thus, the aim of this study was to clarify the factors of poor outcome and mortality in elderly patients with aSAH. METHODS: In the modified World Federation of Neurosurgical Societies (mWFNS) scale study, 1124 patients were divided into 2 groups, elderly (age ≥65 years) and non-elderly (age <65 years), with aSAH investigated between October 2010 and March 2013 in Japan. The odds ratio (OR) and 95% confidence interval (CI) of each risk factor was calculated through multivariate logistic regression analysis for poor outcomes, as indicated by the modified Rankin Scale (mRS) score ≥3 and mortality at 3 months after onset in each group. RESULTS: Both groups demonstrated that the mWFNS scale was significant as a grade order risk factor for poor outcomes and mortality associated with disease. In the elderly group, risk factors for poor outcomes at 3 months after onset were older age (OR 1.10, 95% CI 1.06-1.14), male sex (OR 2.03, 95% CI 1.10-3.73), and severe cerebral vasospasm category (OR 10.13, 95% CI 4.30-23.87). Risk factors for mortality at 3 months after onset were older age (OR 1.06, 95% CI 1.01-1.11) and severe vasospasm category (OR 2.17, 95% CI 1.00-4.72). CONCLUSIONS: The mWFNS scale is a useful prognostic predictor for both non-elderly and elderly patients with aSAH. Elderly male patients with aSAH presenting with severe vasospasm should be managed more carefully.

Inhibition of c-Jun N-terminal kinase enhances temozolomide-induced cytotoxicity in human glioma cells.

Previous studies have revealed that p38, a member of the family of stress-activated protein kinases (SAPKs), cooperates with the Chk1-pathway to bring about temozolomide (TMZ)-induced G2 arrest, and that the inhibition of either pathway alone is sufficient to sensitize U87MG glioma cells to TMZ-induced cytotoxicity. c-Jun N-terminal kinase (JNK), another SAPK, has been reported to have several roles of cell survival, oncogenesis, growth, differentiation and cell death. To elucidate the functions of JNK in glioma cells treated with TMZ, we analyzed alterations in JNK and the effect of modification of JNK in U87MG human glioma cells treated with TMZ. We found that JNK was phosphorylated 1-2 days after TMZ treatment and that pretreatment (for 24 h) and post-treatment (for 72 h) with a JNK inhibitor SP600125 at a concentration of 200 nM or higher remarkably reduced clonogenicity in the TMZ-treated cells. The phosphorylation of the JNK target protein c-Jun, but not of ATF-2, was inhibited by this concentration of SP600125. Therefore JNK was proved to have a role of survival in glioma cells treated with TMZ, and c-Jun-related responses were suggested to be more important in the JNK-mediated survival of glioma cells with DNA damage. SP600125 amplified the percentage of senescence-like cells and of mitotic catastrophe cells in TMZ-treated U87MG and U87MG-E6 cells, respectively, suggesting that the enhancement of TMZ-induced cytotoxicity by a JNK inhibitor in glioma cells is induced (at least in part) by the potentiation of cell death pathways induced by TMZ alone. Further investigation based on the present data may provide a viable approach for enhancing TMZ-induced cytotoxicity in human gliomas.

Role of aneurysm projection in "A2" fork orientation for determining the side of surgical approach.

PURPOSE: To determine factors that help decide the side of approach for anterior communicating artery (AComA) aneurysms, based on a prospective study. METHODS: Between January 2004 and January 2006, 93 cases with AComA aneurysms were treated through pterional approach. They were classified as Type I, II (IIa, IIb), III and IV, based on the various projections and size of aneurysm. The principle for the choice of operative side was designed based on the type of aneurysm and the A2 fork orientation (the interrelations between the plane of bilateral A2, AComA, and mid-saggital plane). RESULTS: There were 55 aneurysms of Type I, 10 of Type IIa, 14 of Type IIb, 12 of Type III, and 2 of Type IV. In Types I and IIa, the side posteriorly placed to A2 was chosen for the approach. In Type IIb, the side of the dominant A1 was selected. In Type III, the side anteriorly placed to A2 was chosen. Type IV aneurysms were difficult to handle even if approached from the dominant A1. There were 11 cases treated from the side of non-dominant A1. The overall outcome in the treatment of AComA aneurysms were considered excellent in 90.8% of cases according to the Glasgow Outcome Scale, with complete occlusion of aneurysms and complete patency of parent or perforating arteries. CONCLUSIONS: Applying three-dimensional computed tomography and magnetic resonance angiography, we classified AComA aneurysms as four types and undertook surgical clipping from the chosen side of approach, according to the type of aneurysm and the A2 fork orientation. The selective side of approach on the basis of individual decision-making has led to favourable outcomes.

RNA sequencing analysis revealed the induction of CCL3 expression in human intracranial aneurysms.

Intracranial aneurysm (IA) is a socially important disease as a major cause of subarachnoid hemorrhage. Recent experimental studies mainly using animal models have revealed a crucial role of macrophage-mediated chronic inflammatory responses in its pathogenesis. However, as findings from comprehensive analysis of unruptured human IAs are limited, factors regulating progression and rupture of IAs in humans remain unclear. Using surgically dissected human unruptured IA lesions and control arterial walls, gene expression profiles were obtained by RNA sequence analysis. RNA sequencing analysis was done with read count about 60~100 million which yielded 6~10 billion bases per sample. 79 over-expressed and 329 under-expressed genes in IA lesions were identified. Through Gene Ontology analysis, 'chemokine activity', 'defense response' and 'extracellular region' were picked up as over-represented terms which included CCL3 and CCL4 in common. Among these genes, quantitative RT-PCR analysis using another set of samples reproduced the above result. Finally, increase of CCL3 protein compared with that in control arterial walls was clarified in IA lesions. Findings of the present study again highlight importance of macrophage recruitment via CCL3 in the pathogenesis of IA progression.

Usefulness of a simplified management scheme for paraclinoid aneurysms based on a modified classification.

BACKGROUND: Our objective was to set up a management-oriented classification for paraclinoid aneurysms, and then design and apply a simplified management scheme according to each group defined by this classification. METHODS: Paraclinoid aneurysms were classified as group I (supraophthalmic artery), group II (ophthalmic artery) and group III (infraophthalmic artery) aneurysms intradurally. Between January 2005 and December 2006, 86 cases with 89 paraclinoid aneurysms were treated. There were 35 (40.2%) aneurysms in group I (20 in group Ia, 15 in group Ib), 32 (36.8%) in group II and 20 (23%) in group III. RESULTS: In group I aneurysms, 20 (57.1%) were treated by clipping or/and wrapping, while 15 (42.9%) were managed by coiling. In group II aneurysms, 20 (62.5%) were treated by clipping and 12 (37.5%) by coiling. The contralateral approach was performed for 4 (6%) aneurysms in groups I and II. All 20 group III aneurysms were treated by coiling. The overall rate of permanent complications was 4.6%. The rate of complete occlusion was 92.5% in surgical cases and 55.6% in endovascular ones. The overall outcomes in the treatment of paraclinoid aneurysms were excellent (GOS = 5, 95.4%). CONCLUSION: Based on our modified classification of paraclinoid aneurysms, a simplified management scheme was designed and applied. For group I (supraophthalmic artery) and group II (ophthalmic artery) aneurysms, surgical clipping or/and wrapping should be the first choice of treatment, while for group III (infraophthalmic artery) aneurysms, endovascular coiling should be the best modality. Additionally, individualizing the treatment planning might contribute to better results.

Neuroprotective effect of exogenous microglia in global brain ischemia.

Exogenous microglia pass through the blood-brain barrier and migrate to ischemic hippocampal lesions when injected into the circulation. We investigated the effect of exogenous microglia on ischemic CA1 pyramidal neurons. Microglia were isolated from neonatal mixed brain cultures, labeled with the fluorescent dye PKH26, and injected into the subclavian artery of Mongolian gerbils subjected to ischemia reperfusion neuronal injury. PKH26-labeled microglia migrated to the ischemic hippocampal lesion, resulting in increased numbers of surviving neurons compared with control animals, even when injected 24 h after ischemia. Interferon-gamma stimulation of isolated microglia enhanced the neuroprotective effect. Administration of exogenous microglia resulted in normal performance in a passive avoidance-learning task. Additionally, administration of exogenous microglia increased the expression of brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor in the ischemic hippocampus, and thus might have induced neurotrophin-dependent protective activity in damaged neurons. Peripherally injected microglia exhibited a specific affinity for ischemic brain lesions, and protected against ischemic neuronal injury in vivo. It is possible that administration of exogenous microglia can be developed as a potential candidate therapy for central nervous system repair after transitory global ischemia.

Expression and structure of interleukin 4 receptor (IL-4R) complex in human invasive pituitary adenomas.

Pituitary adenomas are frequently invasive of surrounding tissues, which adversely affects the surgical outcome and the disease-free survival of patients. In the present study, Interleukin 4 receptor (IL-4R) complex has been investigated to figure out whether the three subunits are overexpressed in human invasive pituitary adenomas. Reverse transcription-polymerase chain reaction (RT-PCR) analysis for interleukin 4 receptor alpha (IL-4Ralpha), interleukin 13 receptor alpha1 (IL-13Ralpha1), interleukin 2 receptor gammac (IL-2Rgammac) were performed on total RNA extracted from 10 non-invasive pituitary adenomas, 30 invasive pituitary adenomas, one glioblastoma multiforme, one normal human pituitary tissue sample and one normal human brain tissue sample. Quantitative real-time PCR and in situ immunofluorescence assay were performed in five invasive functioning pituitary adenoma samples and five invasive nonfunctioning pituitary adenoma samples. RT-PCR analysis for IL-4Ralpha, IL-13Ralpha1 and IL-2Rgammac chains were overexpressed in invasive pituitary adenomas. The transcripts for three subunits were not/weakly expressed in normal pituitary tissue and normal brain tissue. The quantitative real-time PCR and in situ immunofluorescence assay confirmed the results of the RT-PCR analysis. Our results indicate that human invasive pituitary adenomas express type III IL-4R complex. These receptors may serve as a novel target for immunotoxin therapy in patients with invasive pituitary adenomas who are not amenable to total surgical resection or for recurrent cases.

Dual-Image Videoangiography During Intracranial Microvascular Surgery.

OBJECTIVE: Indocyanine green videoangiography (ICG-VA) is a valuable tool to assess vessel and aneurysm patency during neurovascular surgical procedures. However, ICG-VA highlights vascular structures, which appear white over a black background. Anatomic relationships are sometimes difficult to understand at first glance. Dual-image videoangiography (DIVA) enables simultaneous visualization of light and near-infrared fluorescence images of ICG-VA. METHODS: The DIVA system was mounted on an OPMI Pentero Flow 800 intraoperative microscope. DIVA was used during microsurgical procedures on 5 patients who were operated for aneurysm clipping and superficial temporal artery-middle cerebral artery bypass. RESULTS: DIVA provides real-time simultaneous visualization of aneurysm and vessels and surrounding structures including brain, nerves, and surgical clips. Although visual contrast between vessels and background is higher with standard black-and-white imaging, DIVA makes it easier to understand anatomic relationships between intracranial structures. DIVA also provides better vision of the depth of field. CONCLUSIONS: DIVA has the potential to become a widely used intraoperative tool to check patency of intracranial vessels. It should be considered as an adjunct to standard ICG-VA for better understanding of vascular anatomy in relation to surrounding structures and can have an impact on decision making during surgery.

State-of-Art Surgical Treatment of Dissecting Anterior Circulation Intracranial Aneurysms.

Intracranial dissecting aneurysms (IDAs) are an important cause of subarachnoid hemorrhage, stroke, or compression of intracranial structures. Since the availability of endovascular treatment and the advantage of intraprocedural anticoagulation, an endovascular strategy has become the mainstay of their therapy. But in some cases selective aneurysm obliteration by the endovascular approach is impossible or associated with an unacceptable risk of morbidity. This is particularly true when the IDA is a blood blister-like aneurysm or when dissection affects peripheral branches of the internal carotid artery. The literature dealing with surgical treatment of IDAs in the anterior circulation is heterogeneous, and formulation of general recommendations concerning the surgical strategy remains difficult. The aim of this study was to conduct a systematic review of the current knowledge on incidence, pathogenesis, clinical presentation, and diagnostic procedures with a special emphasis on the surgical treatment of intracranial dissections of anterior circulation.

CT angiography with electrocardiographically gated reconstruction for visualizing pulsation of intracranial aneurysms: identification of aneurysmal protuberance presumably associated with wall thinning.

Electrocardiographically (ECG) gated multisection helical CT images were obtained in 23 patients with ruptured intracranial aneurysms. 4D-CTA (3D CT angiography plus phase data) images were generated by ECG-gated reconstruction. Four patients showed pulsation of an aneurysmal bleb. Clipping was performed in two of these patients, and the rupture site matched the pulsatile bleb seen in 4D-CTA.

Modified World Federation of Neurosurgical Societies subarachnoid hemorrhage grading system.

OBJECT: A modified World Federation of Neurosurgical Societies scale (m-WFNS scale) for aneurysmal subarachnoid hemorrhage (SAH) recently has been proposed, in which patients with Glasgow Coma Scale (GCS) scores of 14 are assigned to grade II and those with GCS scores of 13 are assigned to grade III regardless of the presence of neurologic deficits. The study objective was to evaluate outcome predictability of the m-WFNS scale in a large cohort. METHODS: This was a multicenter prospective observational study conducted in Japan. A total of 1656 patients with SAH were registered during the 2.5-year study period, and the outcome predictability, using the Glasgow Outcome Scale (GOS) and modified Rankin Scale (mRS) scores at discharge and at 90 days after onset, was evaluated by comparing the m-WFNS with the original WFNS scale. We focused on whether significant differences in these scores were present between the neighboring grades. RESULTS: In the m-WFNS scale, significant difference between any neighboring grades was observed both in the mean GOS and mRS scores at 90 days except between grades III/IV. However, differences were not significant between grades II/III and between grades III/IV in the original WFNS scale. CONCLUSIONS: SAH-induced brain injury may be substantially severer in patients with GCS 13 than those with GCS 14, which may explain why grade III patients faired significantly worse than grade II patients by the modified WFNS scale. Although further validation is necessary, the m-WFNS scale has a potential of providing neurosurgeons with simpler and more reliable prognostication of patients with SAH.