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Objective@#Serum hemoglobin (Hb) level affects the viscosity of blood. Several studies have reported that Hb level is associated with adverse cardiovascular outcome. However, there is a paucity of evidence on the association between serum Hb level and the risk of subclinical atherosclerosis. Thus, the objective of this study was to investigate the relationship between Hb level and risk of carotid plaque in a health checkup cohort. @*Methods@#This retrospective study analyzed a total of 3,805 individuals without history of cardiovascular disease (CVD) who underwent carotid ultrasonography (USG) between January 2016 and June 2018. Participants were divided into 4 groups based on Hb quartiles in each of male and female. Carotid plaque score was calculated based on USG reports.Multivariable logistic regression analysis was performed for each index of quartile groups regarding the risk of carotid plaque. @*Results@#Of 3,805 individuals (mean age, 52.62±10.25 years; 2,674 [70.28%] males), mean Hb level was 15.11±0.75 g/dL in male and 13.35±0.74 g/dL in female. When the Q1 group was compared to the Q4, increasing quartile of Hb was associated with the presence of significant carotid plaque (plaque score ≥3) in male (adjusted odds ratio [OR], 1.538; 95% confidence interval [CI], 1.182–2.001; p=0.001) and female (adjusted OR, 1.749; 95% CI, 1.058–2.676; p=0.01). @*Conclusion@#A high Hb level is associated with an increased risk of carotid plaques in individuals without history of CVD. This finding may support the need for early screening of CVD in individuals with high Hb levels.
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Prosthodontic treatment is being performed for morphology and functional restoration due to damage and loss of teeth. As the aesthetic demands of patients increase, interest in ceramic materials with shades and translucency similar to natural teeth has increased.Recently, the manufacturing and processing technology of ceramic materials has greatly improved, and the market for dental ceramic materials is growing rapidly. The purpose of this literature review and evaluation is to provide information on the classification and properties of dental ceramic materials with excellent aesthetics and fracture resistance. In this article, it is classified as follows: I) Dental porcelain; II) Sinterable all-ceramic; III) Glass-ceramic for casting; IV) Glass-infiltrated alumina ceramic; V) Glass-ceramic ingots for heat-pressing technique; Vl) Blocks for CAD/CAM; Vll) Ceramic for CAD/3D printing. Dental ceramic materials and their restoration manufacturing methods have evolved significantly over the past decade. As a result, the manufacturing method of restorations has progressed from the layered firing technique of powdered materials or heat-pressing technique to the cutting and processing of single and multi-layer blocks using CAD/CAM technology, leading to the introduction of CAD/3D printing technology. In this manuscript, we will review the types of ceramic materials used in the fabrication of dental restorations and their advantages and disadvantages.
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The extremely low frequency-electromagnetic field (ELF-EMF) refers to the frequency range of 0-300 Hz. It has been reported that it causes biological effects on cell survival, growth, and function. Structural changes were observed in the cell membranes of bacteria exposed to a certain intensity of ELF-EMF, indicating that exposure of bacteria to ELF-EMF can directly affect the cell membrane and affect the survival and growth of bacteria. The purpose of this study was to investigate the effect of the application of low frequency square wave positive voltages on Aggregatibactor actinomycetemcomitans (A. actinomycetemcomitans), a putative pathogen of periodontal disease. A square wave positive voltage output of 20 V or less at low frequency (0-300 Hz) was applied to A. actinomycetemcomitans in a range of 60 minutes. Changes in the population of bacteria were observed by absorbance measurement, colony forming unit (CFU/ml) evaluation, and high-resolution field-emission scanning electron microscopy (HR FE-SEM). The results show that the most effective offset and frequency in inhibiting bacterial growth are 0.7V and 7.83 Hz (Schumann resonance). As the applied time increased and the voltage increased, it was effective in inhibiting bacterial growth. These results led to the conclusion that bacterial growth can be inhibited even at low frequencies below 10 Hz, and it was experimentally proven that the frequency, voltage setting, and exposure time of ELF-EMF have a significant effect on reducing the growth of A. actinomycetemcomitans.
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Titanium mesh is commonly employed to reinforce missing alveolar ridges and promote bone regeneration around implants. However, the bioinertness of titanium mesh must be improved. This study evaluated the effect of improving bioactivity and bone regeneration by loading a calcium phosphate coating layer and ibandronate onto a titanium mesh with a nanotube-structured TiO2 layer. The surface treatment of titanium mesh was divided into four groups: (1) No treatment; (2) Formation of nanotube TiO2 layer; (3) Cyclic calcification pretreatment (calcium phosphate coating layer) after the formation of a nanotube TiO2 layer; (4) Calcium phosphate coating and ibandronate loading after the formation of a nanotube TiO2 layer. The release amount of ibandronate was analyzed using a UV spectrophotometer, and bioactivity was assessed through XRD, EDS, and HR FE-SEM to observe changes in the surface layer after immersion in simulated body fluid (SBF). Hydroxyapatite was uniformly distributed on the surface of the (4) group immersed in SBF, and calcium and phosphorus content also increased over time. This result supported that bioactivity was improved. The continuous release of ibandronate over 10 days may contribute to realizing a mechanism that improves osseointegration between bone and titanium mesh. These results showed that bioactivity was improved as calcium phosphate precipitated on the surface of the nanostructured titanium mesh. Additionally, it is believed that combined ibandronate can effectively increase the stability of titanium mesh and promote bone regeneration.
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The purpose of this study was to observe the surface morphology and roughness of micro-hybrid and nano-filled resin composites and compare wear resistance by conducting a toothbrushing wear test with toothpastes with different abrasive ingredients. Two types of resin composites containing micro-hybrid fillers (Z100 Restorative, Filtek Z250) and one type of resin composite containing nanofillers (Filtek Z350 XT) were used. For the toothbrushing wear test, 90 resin composite samples with a diameter of 10 mm and a thickness of 1 mm were prepared. A force of 2 N and 100,000 cycles of brushing were performed using a pin-on-disk wear tester. The toothpastes used in the test were classified into 4 groups according to the abrasive ingredients (hydroxyapatite, calcium carbonate, sodium bicarbonate, and zeolite-M). After the toothbrushing wear test, the surface morphology of the samples was observed using an optical microscope and a scanning electron microscope (SEM), and the surface roughness was measured using atomic force microscopy (AFM). Relatively large filler particles (micro size) protruded from the surface of the micro-hybrid resin composite groups, and small crater-shaped defects were observed. The surface roughness values of the groups that performed the wear test with toothpaste containing zeolite-M were significantly higher than the other groups (P<0.05). The surface roughness value was significantly (P<0.05) highest in the group where the nanofilled resin composite was wear-tested with toothpaste containing zeolite-M. However, regardless of the type of toothpaste, the surface roughness showed low values of less than 0.1 μm. The surface appeared uniform and smooth compared to the surface of micro-hybrid resin composites. Finally, the nano-filled resin composite showed relatively higher wear resistance than the micro-hybrid resin composite. This means that wear resistance during brushing may indicate the durability of the material in the clinic.
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Background@#During the coronavirus disease 2019 (COVID-19) pandemic, there was a shortage of medical resources and the need for proper treatment guidelines for brain tumor patients became more pressing. Thus, the Korean Society for Neuro-Oncology (KSNO), a multidisciplinary academic society, has undertaken efforts to develop a guideline that is tailored to the domestic situation and that can be used in similar crisis situations in the future. As part II of the guideline, this consensus survey is to suggest management options in specific clinical scenarios during the crisis period. @*Methods@#The KSNO Guideline Working Group consisted of 22 multidisciplinary experts on neuro-oncology in Korea. In order to confirm a consensus reached by the experts, opinions on 5 specific clinical scenarios about the management of brain tumor patients during the crisis period were devised and asked. To build-up the consensus process, Delphi method was employed. @*Results@#The summary of the final consensus from each scenario are as follows. For patients with newly diagnosed astrocytoma with isocitrate dehydrogenase (IDH)-mutant and oligodendroglioma with IDH-mutant/1p19q codeleted, observation was preferred for patients with low-risk, World Health Organization (WHO) grade 2, and Karnofsky Performance Scale (KPS) ≥60, while adjuvant radiotherapy alone was preferred for patients with high-risk, WHO grade 2, and KPS ≥60. For newly diagnosed patients with glioblastoma, the most preferred adjuvant treatment strategy after surgery was radiotherapy plus temozolomide except for patients aged ≥70 years with KPS of 60 and unmethylated MGMT promoters. In patients with symptomatic brain metastasis, the preferred treatment differed according to the number of brain metastasis and performance status. For patients with newly diagnosed atypical meningioma, adjuvant radiation was deferred in patients with older age, poor performance status, complete resection, or low mitotic count. @*Conclusion@#It is imperative that proper medical care for brain tumor patients be sustained and provided, even during the crisis period. The findings of this consensus survey will be a useful reference in determining appropriate treatment options for brain tumor patients in the specific clinical scenarios covered by the survey during the future crisis.
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Background@#During the coronavirus disease 2019 (COVID-19) pandemic, the need for appropriate treatment guidelines for patients with brain tumors was indispensable due to the lack and limitations of medical resources. Thus, the Korean Society for Neuro-Oncology (KSNO), a multidisciplinary academic society, has undertaken efforts to develop a guideline that is tailored to the domestic situation and that can be used in similar crisis situations in the future. @*Methods@#The KSNO Guideline Working Group was composed of 22 multidisciplinary experts on neuro-oncology in Korea. In order to reach consensus among the experts, the Delphi method was used to build up the final recommendations. @*Results@#All participating experts completed the series of surveys, and the results of final survey were used to draft the current consensus recommendations. Priority levels of surgery and radiotherapy during crises were proposed using appropriate time window-based criteria for management outcome. The highest priority for surgery is assigned to patients who are life-threatening or have a risk of significant impact on a patient’s prognosis unless immediate intervention is given within 24–48 hours. As for the radiotherapy, patients who are at risk of compromising their overall survival or neurological status within 4–6 weeks are assigned to the highest priority. Curative-intent chemotherapy has the highest priority, followed by neoadjuvant/adjuvant and palliative chemotherapy during a crisis period. Telemedicine should be actively considered as a management tool for brain tumor patients during the mass infection crises such as the COVID-19 pandemic. @*Conclusion@#It is crucial that adequate medical care for patients with brain tumors is maintained and provided, even during times of crisis. This guideline will serve as a valuable resource, assisting in the delivery of treatment to brain tumor patients in the event of any future crisis.
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A 44-year-old female patient who had been diagnosed with breast cancer visited our oncology department. She had developed right-side weakness and mild dysarthria, and MRI revealed a 4-cm cysticenhancing lesion in her left frontal lobe. Her surgery was postponed 48 hours after receiving 5-aminolevulinic acid (5-ALA), because a problem with thyroid function that had not been noticed before was discovered. The main lesion was enhanced on navigation and appeared to be a gross tumor; its 5-ALA uptake was very high. Specimens obtained from this location were histologically confirmed to contain tumor cells. The operation was completed, and removal of all enhancing lesions was confirmed by MRI within 24 hours postoperatively. The pathology report confirmed metastatic ductal carcinoma. The clinical efficacy of 5-ALA was confirmed even 48 hours after administration into a metastatic brain tumor from breast cancer.
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Objective@#: Chronic subdural hematoma (CSDH) patients using antithrombotic agents (AT) at high risk for cardiovascular disease are increasing. The authors aimed to analyze the factors influencing outcome by targeting patients using AT and to establish a desirable treatment strategy. @*Methods@#: A retrospective analysis was performed on data from 462 patients who underwent burr hole trephination (BHT) surgery for CSDH at five hospitals from March 2010 to June 2021. Outcomes included incidence of postoperative acute bleeding, recurrence rate, and morbidity or mortality rate. Patients were divided into the following four groups based on their history of AT use : no AT. Only antiplatelet agents (AP), only anticoagulants (AC), both of AP and AC. In addition, a concurrent literature review was conducted alongside our cohort study. @*Results@#: Of 462 patients, 119 (119/462, 25.76%) were using AT. AP prescription did not significantly delay surgery (p=0.318), but AC prescription led to a significant increase in the time interval from admission to operation (p=0.048). After BHT, AP or AC intake significantly increased the period required for an in-dwelling drain (p=0.026 and p=0.037). The use of AC was significantly related to acute bleeding (p=0.044), while the use of AP was not (p=0.808). Use of AP or AC had no significant effect on CSDH recurrence (p=0.517 and p=1.000) or reoperation (p=0.924 and p=1.000). Morbidity was not statistically correlated with use of either AP or AC (p=0.795 and p=0.557, respectively), and there was no significant correlation with mortality for use of these medications (p=0.470 and p=1.000). @*Conclusion@#: Elderly CSDH patients may benefit from maintenance of AT therapy during BHT due to reduced thromboembolic risk. However, the use of AC necessitates individualized due to potential postoperative bleeding. Careful post-operative monitoring could mitigate prognosis and recurrence impacts.
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Objective@#: Due to the implementation of vaccinations and the development of therapeutic agents, the coronavirus disease 2019 (COVID-19) pandemic that started at the end of 2019 has entered a new phase. As a result, neurosurgeons should reconsider the way they treat their patients. As the COVID-19 situation prolongs, the change in neurosurgical emergency patients according to the number of confirmed cases is no longer clear. Outpatient treatment by telephone was permitted according to government policy. In addition, visits to caregivers in the intensive care unit were limited. @*Methods@#: The electronic medical records of patients who had been treated over the phone for a month (during April 2020, while the hospital was closing) were reviewed. Meanwhile, according to the limited visits to the intensive care unit, a video meeting was held with the caregivers. After the video meeting, satisfaction was evaluated using a questionnaire. @*Results@#: During April 2020, 1021 patients received non-face-to-face care over the telephone. Among the patients, no critical medical problem occurred due to non-face-to-face care. From July 2021 to December 2021, 321 patients were admitted to the neurosurgical intensive care unit and 107 patients (33.3%) including their caregivers agreed to video visits. Twice a week, advance notice was given that access would be made through a mobile device and the nurse explained to caregivers how to use the mobile device. The time for the video meeting was approximately 20 minutes per patient. Based on the questionnaire, 81 respondents (75.7%) answered that they agreed, and 26 respondents (24.3%) answered that they strongly agreed that was easy to communicate through video meetings. Fifty-two (48.6%) agreed and 55 (51.4%) strongly agreed that they were easy to understand the doctor’s explanation. For overall satisfaction with this video meeting, three respondents (2.8%) gave 4/5 points and 95 respondents (88.8%) gave 5/5 points, and nine (8.4%) gave 3/5 points. Their reason was that there was not enough time. @*Conclusion@#: In situations where patient visits are limited, video meetings through a mobile device can provide sufficient satisfaction to caregivers. Telemedicine will likely become common in the near future. Health care professionals should prepare and respond to these needs and changes. Therefore, establishing a system with institutional support is necessary.
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Objective@#: COVID-19 has spread worldwide since the first case was reported in Wuhan, China, in December 2019. Our institution is a regional trauma and emergency center in the northern Gyeonggi Province. The changing trend of patient care in the emergency room of this hospital likely reflects the overall trend of patients in the area. In the present study, whether changes in the surrounding social environment following the outbreak of COVID-19 changed the incidence of neurosurgical emergency patients and whether differences in practice existed were investigated. @*Methods@#: The overall trend was analyzed from January 2020 which is before the outbreak of COVID-19 to September 2020. To remove bias due to seasonal variation, the previous 2 year's records during the same period were reviewed and compared. Confirmed COVID-19 patients in the northern Gyeonggi Province were identified using data released by the government. And patients who came to the emergency department with head trauma and stroke were identified. @*Results@#: Based on the present study results, the total number of neurosurgery emergency patients decreased over the study period. In the trauma patient group, the number of patients not involved in traffic accidents significantly decreased compared with patients involved in traffic accidents. Among the stroke cases, the rate of ischemic stroke was lower than hemorrhagic stroke, although a statistically significant difference was not observed. Meanwhile, an increase in the risk of mortality associated with trauma or stroke cases was not observed during the COVID-19 outbreak compared with the same time period in the previous year. @*Conclusion@#: Due to the occurrence of COVID-19, non-essential activities have decreased and trauma cases not associated with traffic accidents appeared to decrease. Due to the decrease in overall activity, the number of stroke patients has also decreased. This trend is expected to continue even in the post-COVID-19 era, and accordingly, the results from the present study are relevant especially if the current situation continues.
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With the recent rapid increase in obesity worldwide, metabolic syndrome (MetS) has gained significant importance. MetS is a cluster of obesity-related cardiovascular risk factors including abdominal obesity, atherogenic dyslipidemia, high blood pressure and impaired glucose tolerance. MetS is highly prevalent and strongly associated with an increased risk of developing diabetes and cardiovascular disease, putting a great burden on human society. Therefore, it is very important to reduce MetS risk, which can improve patients’cardiovascular prognosis. The primary and most effective strategy to control each component of MetS is lifestyle change such as losing body weight, keeping regular exercise, adopting a healthy diet, quitting smoking and alcohol drinking in moderation. Many studies have shown that lifestyle modification has improved all components of MetS, and reduces the incidence of diabetes and cardiovascular disease. Here, the Korean Society of CardioMetabolic Syndrome has summarized specific and practical methods of lifestyle modification in the management of MetS in the healthcare field.
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Gelatin methacryloyl 3d mesh mimics the natural extracellular matrix which allow loading as promising drug delivery systems.However, insufficient mechanical and degradation properties remain the biggest obstacle for this material application. In this study, a modified hydrogel with natural phytochemical was developed to improve the antibacterial effect by the addition of ginger extract, a natural spicy used in traditional medicine. GelMA hydrogels with ginger extract were fabricated and their chemical and morphological characteristics were analyzed by Fourier transformer infrared spectroscopy and scanning electron microscopy, structural characteristic were evaluated by compressive test and surface wettability analysis. S. mutans, S. aureus and P. gingivalis were used to confirm the antibacterial effect of the modified hydrogels. The FT-IR spectra of the hydrogels modified with ginger presented an increase in intensity of some peaks in comparison with the 10% GelMA hydrogel. The pores of ginger-modified hydrogels decreased it size which affected the hydrogels physical properties, decreasing the compressive modulus and increasing the durability, swelling ratio and, hydrophobicity of the surface. The ginger-modified hydrogels exhibited excellent antibacterial properties against S. mutans and S. aureus at high concentrations of ginger extract, while P. gingivalis presented a higher sensitivity at all tested concentrations. Hence, this study concludes that ginger-modified GelMA hydrogels presented better antibacterial effect, durability over time and, swelling stability.
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Objective@#This study evaluated the effect of cyclic pre-calcification treatment on the improvement of bioactivity and osseointegration of Ti-6Al-4V miniscrews. @*Methods@#The experimental groups were: an untreated group (UT), an anodized and heat-treated group (AH), and an anodized treatment followed by cyclic pre-calcification treatment group (ASPH). A bioactive material with calcium phosphate was coated on the mini-screws, and its effects on bioactivity and osseointegration were evaluated in in vitro and in vivo tests of following implantation in the rat tibia. @*Results@#As a result of immersing the ASPH group in simulated body fluid for 2 days, protrusions appearing in the initial stage of hydroxyapatite precipitation were observed. On the 3rd day, the protrusions became denser, other protrusions overlapped and grew on it, and the calcium and phosphorus concentrations increased. The removal torque values increased significantly in the following order: UT group (2.08 ± 0.67 N·cm), AH group (4.10 ± 0.72 N·cm), and ASPH group (6.58 ± 0.66 N·cm) with the ASPH group showing the highest value (p < 0.05). In the ASPH group, new bone was observed that was connected to the threads, and it was confirmed that a bony bridge connected to the adjacent bone was formed. @*Conclusions@#In conclusion, it was found that the surface treatment method used in the ASPH group improved the bioactivity and osseointegration of Ti-6Al-4V orthodontic miniscrews.
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Chronic subdural hematoma (CSDH), which generally occurs in elderly patients, is a frequently diagnosed condition in neurosurgical departments. Computed tomography (CT) and magnetic resonance imaging (MRI) are the most preferred diagnostic modalities for CSDH assessment. With early diagnosis and adequate management, CSDH may show favorable prognosis in majority of the patients; however, recurrence after surgery can occur in a significant number of patients. The recently increasing number of CSDH studies could reveal the prognostic factors affecting CSDH recurrence. Particularly, radiological characteristics regarding the internal architecture of CSDH are considered closely associated with recurrence in surgically treated CSDH patients. In this literature review, we evaluated the various diagnostic modalities of CSDH and its radiological characteristics on CT and MRI. Furthermore, we summarized the prognostic factors of recurrence for the hematoma type based on the radiological findings.
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The Neurotrauma Clinical Practice Guidelines Committee of the Korean Neurotraumatology Society (KNTS-NCPGC) is developing clinical guidelines for neurotrauma in line with the capabilities of the Korean Neurotraumatology Society, which is leading pioneering development in the field of neurosurgery. From the mid-1990s, the KNTS-NCPGC has been working to develop guidelines and disseminate evidence-based medicine, including the development of Korean guidelines for the management of severe head injuries and active participation in the Clinical Practice Guidelines Committee of the Korean Academy of Medical Sciences. The KNTS-NCPGC strives to write and inherit the will of the society through the development of clinical practice guidelines, which are one of the outcomes representing professionalism and public interest and can be expressed in terms of “trust” and “best.” In this review, the history and achievements of KNTS-NCPGC, the status of the ongoing development of guidelines, and the perspectives of the committee are covered.
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A lesion in the medial longitudinal fasciculus (MLF) causes internuclear ophthalmoplegia (INO). Many intracranial lesions, such as multiple sclerosis or vascular disorders may be associated with INO; however, INO is a rare complication of minor head injury. The mechanism underlying injury to the MLF may be shear force on the brain stem during head trauma. The shear force can tear or stretch the fibers of the MLF and can also lead to compromise or rupture of the perforating branches of the basilar artery. We present an unusual case of unilateral INO after minor head injury in a patient with a small site of hemorrhage in the midline of the pontomesencephalic junction, confirmed by brain magnetic resonance imaging using susceptibility-weighted imaging.
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Objective@#Emergency cricothyroidotomy is an infrequently performed procedure and post-procedural complications may result from attempting to pass a device with a large external diameter through the cricothyroid membrane. This study aimed to determine the maximum height of the cricothyroid membrane according to the patient’ s sex and age based on cervical-spine computed tomography (C-spine CT) in the emergency department (ED) and determine the appropriate endotracheal tube (ETT) size. @*Methods@#A retrospective analysis of patients was conducted from May 2014 to April 2020 in the ED. The data were obtained from medical records. Electronic calipers were used to measure the maximum height of the cricothyroid membrane in C-spine CT by an emergency physician and an emergency medicine resident. @*Results@#Six hundred and sixty-four patients were included in the study. The mean height of the cricothyroid membrane was 10.11±2.24 mm in males (n=351) and 8.90±1.84 mm in females (n=313) (P<0.001). In males, the cricothyroid membrane height showed significant variance between the ≥75-year-old and the 25-34-year-old groups (9.26±2.40 mm vs. 11.80±2.36 mm) (P<0.001). The tube size of the cricothyroidotomy equipment was suitable for more than 72.1% of patients when applied with an ETT (internal diameter ≤6.0 mm). @*Conclusion@#This study showed that the height of the cricothyroid membrane differed according to sex and also age in males. It may thus be necessary to consider anatomical differences according to sex and age when selecting the appropriate tube size to reduce complications during emergency cricothyroidotomy.
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The objective of the present study was to investigate the effects of heat treatment (HT) time on the optical properties, mechanical properties, and microstructure of lithium disilicate (Li 2 Si 2 O 5) glass-ceramic blocks. Samples were prepared by cutting lithium disilicate glass-ceramic blocks – Amber® Mill Prototype (AMP) and IPS e.max CAD (IEC) – into a disc shape (diameter of 12 mm and thickness of 1.2 mm) and evenly polishing the surface. Each sample was heat treated according to the manufacturer’s manual and HT holding time was set to 15, 30, 45, and 60 minutes according to different groups. The samples were tested by color difference analysis using a spectrophotometer. X-ray diffraction analysis, HR FE-SEM observation, Vickers hardness test, fracture toughness test, and biaxial flexural strength test were carried out. The acicular crystals of lithium disilicate became coarser and less transparent with increasing HT time. The results for color difference (ΔE * ) compared to VITA A2 standard shade showed that the difference was significantly higher in the AMP groups than the IEC groups (P<0.05). Translucency parameter (TP) values were significantly higher in the AMP groups than the IEC groups (P<0.05). The AMP30 group showed the highest TP value, while all other experimental groups showed the tendency of decrease in TP value with increase in HT time. Moreover, increase in TP value was associated with decrease in contrast ratio. When fracture toughness was measured by indentation fracture method, both AMP and IEC groups showed similar results with 1.77 MPa·m 1/2 after HT for 15 minutes. However, as HT time increased, the IEC groups showed significantly higher values than the AMP groups (P<0.05). X-ray diffraction analysis results showed that quartz (SiO 2) and cristobalite (SiO 2) peaks were observed together with the lithium disilicate (Li 2Si 2O 5) peak in the AMP groups, whereas a lithium phosphate (Li 3PO 4) peak was observed together with the lithium disilicate (Li 2Si 2O 5) peak in the IEC groups. With respect to biaxial flexural strength in the AMP groups, the AMP15 group (HT for 15 minutes) showed the highest value of (524.09±89.95) MPa, whereas the AMP60 group (HT for 60 minutes) showed the lowest value of (446.56±76.75) MPa, with a significant difference between the two groups (P<0.05). In the IEC groups, IEC30 group showed the highest value of (668.51±158.57) MPa and the IEC45 group showed the lowest value of (517.37±129.52) MPa, with a significant difference between the two groups (P<0.05). Within the limitations of the present study, it is concluded that if increased strength is required when fabricating restorations using lithium disilicate glass-ceramic, then changing the HT time could be considered as long as such change does not significantly alter the color tone.
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Objective@#: Chronic subdural hematoma (CSDH) is a common disease in neurosurgical departments, but optimal perioperative management guidelines have not yet been established. We aimed to assess the current clinical management and outcomes for CSDH patients and identify prognostic factors for CSDH recurrence. @*Methods@#: We enrolled a total of 293 consecutive patients with CSDH who underwent burr hole craniostomy at seven institutions in 2018. Clinical and surgery-related characteristics and surgical outcomes were analyzed. The cohort included 208 men and 85 women. @*Results@#: The median patient age was 75 years. Antithrombotic agents were prescribed to 105 patients. History of head trauma was identified in 59% of patients. Two hundred twenty-seven of 293 patients (77.5%) had unilateral hematoma and 46.1% had a homogenous hematoma type. About 70% of patients underwent surgery under general anesthesia, and 74.7% underwent a single burr hole craniostomy surgery. Recurrence requiring surgery was observed in 17 of 293 patients (5.8%), with a median of 32 days to recurrence. The postoperative complication rate was 4.1%. In multivariate analysis, factors associated with CSDH recurrence were separated hematoma type (odds ratio, 3.906; p=0.017) and patient who underwent surgery under general anesthesia had less recurrence (odds ratio, 0.277; p=0.017). @*Conclusion@#: This is the first retrospective multicenter generalized cohort pilot study in the Republic of Korea as a first step towards the development of Korean clinical practice guidelines for CSDH. The type of hematoma and anesthesia was associated with CSDH recurrence. Although the detailed surgical method differs depending on the institution, the surgical treatment of CSDH was effective. Further studies may establish appropriate management guidelines to minimize CSDH recurrence.