Topological Surface State Evolution in Bi2Se3 via Surface Etching.

Topological insulators are materials that have an insulating bulk interior while maintaining gapless boundary states against back scattering. Bi2Se3 is a prototypical topological insulator with a Dirac-cone surface state around Γ. Here, we present a controlled methodology to gradually remove Se atoms from the surface Se-Bi-Se-Bi-Se quintuple layers, eventually forming bilayer-Bi on top of the quintuple bulk. Our method allows us to track the topological surface state and confirm its robustness throughout the surface modification. Importantly, we report a relocation of the topological Dirac cone in both real space and momentum space as the top surface layer transitions from quintuple Se-Bi-Se-Bi-Se to bilayer-Bi. Additionally, charge transfer among the different surface layers is identified. Our study provides a precise method to manipulate surface configurations, allowing for the fine-tuning of the topological surface states in Bi2Se3, which represents a significant advancement toward nanoengineering of topological states.

Dominant Charge Density Order in TaTe_{4}.

Electronic orders such as charge density wave (CDW) and superconductivity raise exotic physics and phenomena as evidenced in recently discovered kagome superconductors and transition metal chalcogenides. In most materials, CDW induces a weak, perturbative effect, manifested as shadow bands, minigaps, resistivity kinks, etc. Here we demonstrate a unique example-transition metal tetratellurides TaTe_{4}, in which the CDW order dominates the electronic structure and transport properties. Using angle-resolved photoemission spectroscopy, we found that the band structure of CDW TaTe_{4} is characterized by small, bulk electron pockets. Density functional theory analyses reveal their CDW origin from the folding of the original, large Fermi pockets. Importantly, the CDW induced pockets result in prominent frequencies in the quantum oscillation of the magnetoresistance. Satisfactory agreements are reached between results from photoemission spectroscopy, density functional theory, and quantum oscillation, concerning the shape, size, location, and angle dependence of the CDW pockets. Our results underline transition metal tetratellurides as an outstanding example for exploring the interplay between CDW, pressure induced superconductivity, and potential topological states under strong field.

Effects of Cryopreservation on Microparticles Concentration, Procoagulant Function, Size Distribution, and Morphology.

BACKGROUND Research on microparticles is rapidly evolving and has extended to the field of many diseases. It is unclear whether microparticles can be stored frozen. In this study, our goal was to verify whether cryopreservation had an effect on the properties of the microparticles. MATERIAL AND METHODS We obtained C57BL/6J mouse-derived microparticles by grinding and gradient centrifugation. The specimens were divided into 2 groups: without dimethyl sulfoxide and with dimethyl sulfoxide. The microparticles were then stored at 25°C, 4°C, -20°C, -80°C, and -196°C for 0.5 days, 1 day, 3 days, 5 days, and 7 days. We tested whether the concentration, coagulation function, diameter distribution, and morphology of the microparticles in the 2 groups changed compared to those of a fresh sample. RESULTS We discovered that the concentrations of total microparticles, annexin V-positive microparticles, and brain-derived microparticles changed with freezing. The coagulation function, morphology, and size distribution of the microparticles were also affected by cryopreservation. Finally, there was no difference in the effects of cryopreservation on microparticles between the dimethyl sulfoxide group and the dimethyl sulfoxide-free group. CONCLUSIONS This study suggests that cryopreservation has diverse effects on microparticles within 1 week and that dimethyl sulfoxide has no protective effect on cryopreserved microparticles. Therefore, microparticles should be used fresh for future studies, and they should not be cryopreserved with or without dimethyl sulfoxide.

Meta-analysis of topical vancomycin powder for microbial profile in spinal surgical site infections.

OBJECTIVES: To systematically evaluate the impact of topical vancomycin powder for microbial profile in spinal surgical site infections. METHODS: All available literature regarding the topical use of vancomycin powder to prevent postoperative spinal infections was retrieved from the MEDLINE, EMBASE, and Cochrane databases starting from the creation date and up until September 30, 2018. RESULTS: A total of 21 studies involving 15,548 patients were reviewed. The combined odds ratio showed that topical use of vancomycin powder was effective for reducing the incidence of gram-positive bacterial infections in spinal surgical sites (OR 0.41, P < 0.00001) without affecting its efficacy in the prevention of polymicrobial infections (OR 0.30, P = 0.03). Additionally, it could significantly reduce the infection rate of methicillin-resistant staphylococcus (OR 0.34, P < 0.0001). However, topical vancomycin powder showed no advantage for preventing gram-negative bacterial infections (OR 0.94, P = 0.75). CONCLUSIONS: Topical administration of vancomycin powder may not increase the rates of gram-negative bacterial or polymicrobial infections in spinal surgical sites. On the contrary, it can significantly reduce the infection rates of gram-positive bacteria, methicillin-resistant staphylococcus (MRS) and microorganism. Of course, the topical vancomycin powder cannot change the rates of gram-negative bacterial infections, which may be related to the antimicrobial spectrum of vancomycin. Due to the limited number of articles included in this study, additional large-scale and high-quality studies are needed to provide more reliable clinical evidence.

Histopathological analysis of the wall enhancement of the spinal dural arteriovenous fistulae's draining veins.

OBJECTIVE: The mechanism behind SDAVF is still unclear. We discovered that the vessel wall of the SDAVF-DV occasionally showed enhancement in MRI, and this study assessed the relationship between the enhancement of the draining vein's wall and its histology. METHODS: For histopathologic analysis, 16 draining vein samples from 16 patients with SDAVF were included, 3 normal arteries and 3 normal veins were chosen as comparison. We assessed the imaging and microscopic characteristics of the draining veins in SDAVF patients. The former included the presence of significant enhancement of the wall of the draining vein in MRI, and the latter included the adherence, aggregation, infiltration of pro-inflammatory factors and inflammatory cells. Immuno-histochemical staining was performed using IL-1ß, IL-8, TGF-ß as well as MPO and MMP-9, and positive results were counted. Multiple logistic regression analysis was used to determine whether the infiltration of inflammatory cells was connected to vessel wall enhancement in the SDAVF-DV. RESULTS: Infiltration of inflammatory cells was significantly higher in SDAVF-DV compared to normal vessels, 7 out of 16 patients significantly had enhancement of the vessel wall of SDAVF-DV, and logistic regression analysis showed that samples with more infiltration of inflammatory cells were more likely to show enhancement of the SDAVF-DV walls. CONCLUSION: There was considerable inflammatory cells infiltration in SDAVF-DV, and this may explain why their vessel wall had such a significant enhancement in MRI.

On the topological surface states of the intrinsic magnetic topological insulator Mn-Bi-Te family.

We review recent progress in the electronic structure study of intrinsic magnetic topological insulators (MnBi2Te4) · (Bi2Te3)n ([Formula: see text]) family. Specifically, we focus on the ubiquitously (nearly) gapless behavior of the topological Dirac surface state observed by photoemission spectroscopy, even though a large Dirac gap is expected because of surface ferromagnetic order. The dichotomy between experiment and theory concerning this gap behavior is perhaps the most critical and puzzling question in this frontier. We discuss various proposals accounting for the lack of magnetic effect on the topological Dirac surface state, which are mainly categorized into two pictures, magnetic reconfiguration and topological surface state redistribution. Band engineering towards opening a magnetic gap of topological surface states provides great opportunities to realize quantized topological transport and axion electrodynamics at higher temperatures.

Spinal Lymphatic Dysfunction Aggravates the Recovery Process After Spinal Cord Injury.

We aimed to evaluate the role of the spinal lymphatic system in spinal cord injury and whether it has an impact on recovery after spinal cord injury. Flow cytometry was used to evaluate the changes in the number of microvesicles after spinal cord injury. Evans blue extravasation was used to evaluate the function of the lymphatic system. Evans blue extravasation and immunofluorescence were used to evaluate the permeability of blood spinal cord barrier. The spinal cord edema was evaluated by dry and wet weight.Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay was used to evaluate apoptosis after spinal cord injury. Nuclear factor-kappa B pathway was detected by Western blot. Behavioral tests were used to evaluate limb function. Microvesicles released after spinal cord injury can enter the thoracic duct and then enter the blood through the lymph around the spine. After ligation of the thoracic duct, it can aggravate the neuropathological manifestations and limb function after spinal cord injury. The potential mechanism may involve nuclear factor-kappa B pathway.

Nematic Ising superconductivity with hidden magnetism in few-layer 6R-TaS2.

In van der Waals heterostructures (vdWHs), the manipulation of interlayer stacking/coupling allows for the construction of customizable quantum systems exhibiting exotic physics. An illustrative example is the diverse range of states of matter achieved through varying the proximity coupling between two-dimensional (2D) quantum spin liquid (QSL) and superconductors within the TaS2 family. This study presents a demonstration of the intertwined physics of spontaneous rotational symmetry breaking, hidden magnetism, and Ising superconductivity (SC) in the three-fold rotationally symmetric, non-magnetic natural vdWHs 6R-TaS2. A distinctive phase emerges in 6R-TaS2 below a characteristic temperature (T*) of approximately 30 K, which is characterized by a remarkable set of features, including a giant extrinsic anomalous Hall effect (AHE), Kondo screening, magnetic field-tunable thermal hysteresis, and nematic magneto-resistance. At lower temperatures, a coexistence of nematicity and Kondo screening with Ising superconductivity is observed, providing compelling evidence of hidden magnetism within a superconductor. This research not only sheds light on unexpected emergent physics resulting from the coupling of itinerant electrons and localized/correlated electrons in natural vdWHs but also emphasizes the potential for tailoring exotic quantum states through the manipulation of interlayer interactions.

Bone-to-Bone Ligament Preserving Laminoplasty with Ultrasonic Osteotome Assistance for Intraspinal Tumors: A Technical Note and Clinical Follow-Up.

OBJECTIVE: Laminectomy has been widely used for intraspinal tumor resection. However, the tilted spinous process and narrow lateral laminae of the thoracic spine along with the hypertrophic ligamentum flavum of the lumbar spine pose certain problems for the laminae removal of the traditional laminectomy. We improved the laminectomy method with ultrasonic osteotome to treat thoracolumbar tumors and assessed its safety and superiority. METHODS: A retrospective analysis was performed in 86 patients with thoracolumbar (T4-L5) spinal tumors treated by resection, including 44 with the lamina removed using the traditional method and 42 with the lamina removed using the bone-to-bone ligament preserving (BLP) laminoplasty, which preserves the posterior ligament complex. Age, sex, and tumor size, location, and depth were compared between the two groups. The length of incision and bone window, time to remove the vertebral lamina, and epidural effusion volume were recorded at 2 weeks after surgery in the two groups. Postoperative reexamination by magnetic resonance imaging (MRI) at 2 weeks and 3 months after surgery was compared with preoperative MRI to assess the change in vertebral lamina displacement. RESULTS: There were no statistical differences in age, sex, and tumor size, depth, or location between the two groups. The BLP laminectomy did not increase the risk of dural, spinal cord, or nerve injuries. The difference between the incision and tumor length, as well as the difference between the bone window and tumor length in the BLP laminectomy group, were smaller than those in the traditional laminectomy group, and the BLP laminectomy took less time compared to that of the traditional laminectomy (p < 0.05). There was no significant difference in the volume of epidural effusion between the two groups at 2 weeks postoperatively, or in the displacement of the returned vertebral plate observed in sagittal and axial positions. The same was true for the displacement at 3 months postoperatively in the axial position. However, the sagittal displacement in the BLP laminectomy group was smaller than that in the traditional laminectomy group (p < 0.05). CONCLUSIONS: The BLP laminectomy is safe for the resection of thoracolumbar spinal canal tumors. It is less traumatic and faster, with less displacement of the returned lamina, resulting in a stable repair of the spine.

Maraviroc promotes recovery from traumatic brain injury in mice by suppression of neuroinflammation and activation of neurotoxic reactive astrocytes.

Neuroinflammation and the NACHT, LRR, and PYD domains-containing protein 3 inflammasome play crucial roles in secondary tissue damage following an initial insult in patients with traumatic brain injury (TBI). Maraviroc, a C-C chemokine receptor type 5 antagonist, has been viewed as a new therapeutic strategy for many neuroinflammatory diseases. We studied the effect of maraviroc on TBI-induced neuroinflammation. A moderate-TBI mouse model was subjected to a controlled cortical impact device. Maraviroc or vehicle was injected intraperitoneally 1 hour after TBI and then once per day for 3 consecutive days. Western blot, immunohistochemistry, and TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling) analyses were performed to evaluate the molecular mechanisms of maraviroc at 3 days post-TBI. Our results suggest that maraviroc administration reduced NACHT, LRR, and PYD domains-containing protein 3 inflammasome activation, modulated microglial polarization from M1 to M2, decreased neutrophil and macrophage infiltration, and inhibited the release of inflammatory factors after TBI. Moreover, maraviroc treatment decreased the activation of neurotoxic reactive astrocytes, which, in turn, exacerbated neuronal cell death. Additionally, we confirmed the neuroprotective effect of maraviroc using the modified neurological severity score, rotarod test, Morris water maze test, and lesion volume measurements. In summary, our findings indicate that maraviroc might be a desirable pharmacotherapeutic strategy for TBI, and C-C chemokine receptor type 5 might be a promising pharmacotherapeutic target to improve recovery after TBI.

Hypertrophy of paravertebral muscles after epidural electrical stimulation shifted: A case report.

Epidural electrical stimulation (EES) has been used to improve motor function in patients with chronic spinal cord injury (SCI). The effect of EES on paravertebral muscles in patients with SCI has been unnoticed. We reported a case of paravertebral muscles hypertrophy after the electrode shifted in a patient with spinal cord injury. We also discussed possible mechanistic accounts for this occurs.

Extracellular Mitochondria Activate Microglia and Contribute to Neuroinflammation in Traumatic Brain Injury.

Traumatic brain injury (TBI)-induced neuroinflammation is closely associated with poor outcomes and high mortality in affected patients, with unmet needs for effective clinical interventions. A series of causal and disseminating factors have been identified to cause TBI-induced neuroinflammation. Among these are cellular microvesicles released from injured cerebral cells, endothelial cells, and platelets. In previous studies, we have put forward that cellular microvesicles can be released from injured brains that induce consumptive coagulopathy. Extracellular mitochondria accounted for 55.2% of these microvesicles and induced a redox-dependent platelet procoagulant activity that contributes to traumatic brain injury-induced coagulopathy and inflammation. These lead to the hypothesis that metabolically active extracellular mitochondria contribute to the neuroinflammation in traumatic brain injury, independent of their procoagulant activity. Here, we found that these extracellular mitochondria induced polarization of microglial M1-type pro-inflammatory phenotype, aggravating neuroinflammation, and mediated cerebral edema in a ROS-dependent manner. In addition, the effect of ROS can be alleviated by ROS inhibitor N-ethylmaleimide (NEM) in vitro experiments. These results revealed a novel pro-inflammatory activity of extracellular mitochondria that may contribute to traumatic brain injury-associated neuroinflammation.

Indirect visual guided fracture reduction robot based on external markers.

BACKGROUND: Traditional fracture reduction surgery cannot ensure the accuracy of the reduction while consuming the physical strength of the surgeon. Although monitoring the fracture reduction process through radiography can improve the accuracy of the reduction, it will bring radiation harm to both patients and surgeons. METHODS: We proposed a novel fracture reduction solution that parallel robot is used for fracture reduction surgery. The binocular camera indirectly obtains the position and posture of the fragment wrapped by the tissue by measuring the posture of the external markers. According to the clinical experience of fracture reduction, a path is designed for fracture reduction. Then using position-based visual serving control the robot to fracture reduction surgery. The study is approved by the ethics committee of the Rehabilitation Hospital, National Research Center for Rehabilitation Technical Aids, Beijing, China. RESULTS: Ten virtual cases of fracture were used for fracture reduction experiments. The simulation and model bone experiments are designed respectively. In model bone experiments, the fragments are reduced without collision. The angulation error after the reduction of this method is 3.3° ± 1.8°, and the axial rotation error is 0.8° ± 0.3°, the transverse stagger error and the axial direction error after reduction is 2 ± 0.5 mm and 2.5 ± 1 mm. After the reduction surgery, the external fixator is used to assist the fixing, and the deformity will be completely corrected. CONCLUSIONS: The solution can perform fracture reduction surgery with certain accuracy and effectively reduce the number of radiographic uses during surgery, and the collision between fragments is avoided during surgery.

Momentum-resolved visualization of electronic evolution in doping a Mott insulator.

High temperature superconductivity in cuprates arises from doping a parent Mott insulator by electrons or holes. A central issue is how the Mott gap evolves and the low-energy states emerge with doping. Here we report angle-resolved photoemission spectroscopy measurements on a cuprate parent compound by sequential in situ electron doping. The chemical potential jumps to the bottom of the upper Hubbard band upon a slight electron doping, making it possible to directly visualize the charge transfer band and the full Mott gap region. With increasing doping, the Mott gap rapidly collapses due to the spectral weight transfer from the charge transfer band to the gapped region and the induced low-energy states emerge in a wide energy range inside the Mott gap. These results provide key information on the electronic evolution in doping a Mott insulator and establish a basis for developing microscopic theories for cuprate superconductivity.

Spectroscopic evidence of superconductivity pairing at 83 K in single-layer FeSe/SrTiO3 films.

Single-layer FeSe films grown on the SrTiO3 substrate (FeSe/STO) have attracted much attention because of their possible record-high superconducting critical temperature (Tc) and distinct electronic structures. However, it has been under debate on how high its Tc can really reach due to the inconsistency of the results from different measurements. Here we report spectroscopic evidence of superconductivity pairing at 83 K in single-layer FeSe/STO films. By preparing high-quality single-layer FeSe/STO films, we observe strong superconductivity-induced Bogoliubov back-bending bands that extend to rather high binding energy ~ 100 meV by high-resolution angle-resolved photoemission measurements. They provide a new definitive benchmark of superconductivity pairing that is directly observed up to 83 K. Moreover, we find that the pairing state can be further divided into two temperature regions. These results indicate that either Tc as high as 83 K is achievable, or there is a pseudogap formation from superconductivity fluctuation in single-layer FeSe/STO films.

[Expression of CXCR4 and VEGF in hemangioblastomas of the central nervous system and its relation to tumor angiogenesis].

OBJECTIVE: To evaluate the relationships of CXCR4 (chemokine stromal cell-drived factor-1 receptor) and VEGF (vaseular endothelial growth factor) expression to tumor angiogenesis in hemangioblastomas of the central nervous system. METHODS: The protein expressions of CXCR4 and VEGF were detected by SP immunohistochemical staining in 40 hemangioblastomas. The endothelial cells of blood vessels within the tumor were labeled by CD34, then the microvessel density (MVD) was calculated. RESULTS: Total positive expression rates of CXCR4 and VEGF were 95% (38/40) and 85% (34/40) respectively. The expression rates of CXCR4 and VEGF were found positive obviously in hemangioblastomas compared with the normal cerebellar tissues (P < 0.01). CXCR4 expression was located in the nucleus of tumor stromal cells. VEGF expression was located in the cytoplasm and membrane of tumor stromal cells and some endothelial cells. VEGF has significant positive correlation with the expression level of CXCR4 (r = 0.704, P <0.001). MVD also has significant positive correlation with the expression level of CXCR4 and VEGF (P < 0.001). But there is no significant difference between the cystic and solid tumors, VHL disease and sporadic disease on the expression level of CXCR4, VEGF and MVD (P > 0.05). CONCLUSION: CXCR4 and VEGF may collaborate to induce angiogenesis in hemangioblastomas.

Atorvastatin Combined with Low-Dose Dexamethasone Treatment Protects Endothelial Function Impaired by Chronic Subdural Hematoma via the Transcription Factor KLF-2.

OBJECTIVE: Our previous study showed that the combination therapy with atorvastatin and low-dose dexamethasone protected endothelial cell function in chronic subdural hematoma (CSDH) injury. In this study, we aimed to investigate the mechanism underlying the effects of this combination therapy on CSDH-induced cell dysfunction. METHODS: Monocytes and endothelial cells were cocultured with CSDH patient hematoma samples to mimic the pathological microenvironment of CSDH. Monocytes (THP-1 cells) and endothelial cells (hCMEC/D3 cells) were cocultured in a transwell system for 24 h before stimulation with hematoma samples diluted in endothelial cell medium (ECM) at a 1:1 ratio. Tight junction markers were detected by Western blotting, PCR and immunofluorescence. hCMEC/D3 cells were collected for Western blot and PCR analyses to detect changes in the expression levels of vascular cell adhesion molecule (VCAM-1), intercellular adhesion molecule (ICAM-1), and Kruppel-like factor 2 (KLF-2). The IL-6, IL-10 and VEGF levels in the supernatant were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: KLF-2 expression in endothelial cells was decreased after stimulation with CSDH patient hematoma samples, but combination therapy with atorvastatin and low-dose dexamethasone reversed this trend. KLF-2 protected injured cells by increasing the expression of VE-cadherin and ZO-1; attenuating the expression of VCAM-1, ICAM-1, IL-6 and VEGF; and enhancing the expression of IL-10, all of which play pivotal roles in endothelial inflammation. Moreover, the effect of combination therapy with atorvastatin and low-dose dexamethasone was obviously reduced in endothelial cells with KLF-2 knockdown compared with normal cells. CONCLUSION: Coculture with hematoma samples decreased KLF-2 expression in human cerebral endothelial cells. Combination therapy with atorvastatin and low-dose dexamethasone counteracted hematoma-induced KLF-2 suppression in human cerebral endothelial cells to attenuate robust endothelial inflammation and permeability. KLF-2 plays an important role in drug therapy for CSDH and may become the key factor in treatment and prognosis.

Indirect visual guided fracture reduction robot based on external markers.

BACKGROUND: Traditional fracture reduction surgery cannot ensure the accuracy of the reduction while consuming the physical strength of the surgeon. Although monitoring the fracture reduction process through radiography can improve the accuracy of the reduction, it will bring radiation harm to both patients and surgeons. METHODS: We proposed a novel fracture reduction solution that parallel robot is used for fracture reduction surgery. The binocular camera indirectly obtains the position and posture of the fragment wrapped by the tissue by measuring the posture of the external markers. According to the clinical experience of fracture reduction, a path is designed for fracture reduction. Then using position-based visual serving control the robot to fracture reduction surgery. The study is approved by the Rehabilitation Hospital, National Research Center for Rehabilitation Technical Aids, Beijing , China. RESULTS: 10 virtual cases of fracture were used for fracture reduction experiments. The simulation and model bone experiments are designed respectively. In model bone experiments, the fragments are reduction without collision. The angulation error after the reduction of this method is:3.3°±1.8°, and the axial rotation error is 0.8°±0.3°, the transverse stagger error and the axial direction error after reduction is 2mm±0.5mm and 2.5mm±1mm. After the reduction surgery, the external fixator is used to assist the fixing, and the deformity will be completely corrected. CONCLUSIONS: The solution can perform fracture reduction surgery with certain accuracy and effectively reduce the number of radiographic uses during surgery, and the collision between fragments is avoided during surgery. This article is protected by copyright. All rights reserved.

Detection of Germline Mutations of the SMARCB1 Gene in a Chinese Family with Intraspinal Schwannomatosis.

BACKGROUND: Schwannomatosis is the third subtype of neurofibromatosis. Because the tumor is multiple and prone to recurrence, it often brings challenges to clinical diagnosis and treatment. In the past decade, researchers have come to realize the relationship between the SMARCB1 gene and schwannomatosis, which is expected to improve the current level of diagnosis and treatment. CASE DESCRIPTION: We collected the clinical data of intraspinal schwannomatosis in the same family, which is rare, and carried out the genetic tests on 3 generations of family members (N = 25). We found that 8 family members had germline mutations of the SMARCB1 gene, manifested as mutation at the splice site between SMARCB1 gene exon 8 and 9 (c.1118 + 1G > A). CONCLUSIONS: The structural and functional abnormalities of proteins caused by the mutations of the SMARCB1 gene may be the molecular basis for the pathogenesis of schwannomatosis in this family. This study may provide clues for the study of schwannomatosis in the future.

Meta-Analysis of Prognosis of Different Treatments for Symptomatic Moyamoya Disease.

OBJECTIVE: The purpose of this study was to evaluate the efficacy of surgical revascularization versus conservative treatment and different surgical modalities, in order to provide evidence for the patient with moyamoya disease (MMD) to choose the appropriate treatment. METHODS: We comprehensively searched PubMed, Embase, Web of Science, and the Cochrane Library for articles published regarding MMD treatment. If the I2 value, which evaluated the heterogeneity, was <50%, a fixed-effect model was used; if not, a random effect model was applied. RESULTS: Twenty-seven articles were included in the meta-analysis. The surgery group is more advantageous in reducing the risk of future stroke events than conservative treatment in MMD patients (odds ratio [OR] 0.26, 95% confidence interval [CI] 0.20-0.33, P < 0.001). In addition, the surgical group also had an advantage in terms of increased cerebral perfusion (OR 7.16, 95% CI 3.28-15.64, P < 0.001) and death due to rebleeding (OR 0.27, 95% CI 0.10-0.72, P < 0.01). Direct surgery showed a significant efficacy over indirect surgery (OR 2.03, 95% CI 1.32-3.13, P < 0.01). No obvious difference was found between the direct and indirect bypass subset (OR 0.76, 95% CI 0.51-1.14, P = 0.185). Angiographic results in patients undergoing direct bypass surgery are more pronounced (OR 0.20, 95% CI 0.06-0.67, P < 0.01). CONCLUSIONS: In patients with symptomatic moyamoya disease, bypass surgery is more effective than conservative treatment to prevent future strokes. In surgical patients, direct bypass seems to reduce the risk of stroke more than an indirect bypass.