Fetal lower urinary tract obstruction (LUTO) is a congenital condition in which the bladder fails to excrete urine through the urethra. The primary goal of prenatal treatment for LUTO is the prevention of renal impairment and pulmonary hypoplasia. Vesico-amniotic shunt (VAS) has been the fetal intervention of choice; however, VAS has some limitations, including excretion of urine through an unphysiologic bypass and the need for postnatal corrective reoperation. In this study, we present a novel fetal intervention, a “retro-cystoscopic urethral approach,” performed on a male fetus at 20 weeks gestation diagnosed with enlarged bladder and bilateral hydronephrosis. This approach aims to dilate the narrowed urethra by inserting a urinary catheter using guidewire through a fetal cysto scope. The whole procedure was monitored under real-time ultrasonographic guidance. Despite prenatal intervention, the fetus required multiple cystocenteses, and the bladder dilation persisted.Postnatally, he was diagnosed with megacystis microcolon intestinal hypoperistalsis syndrome, a non-obstructive condition which is relatively rare in male infants. Our case emphasizes the compl exity of diagnosing LUTO during the prenatal period. Further studies exploring novel prenatal interven tions should pay more attention to candidate selection. Additionally, a thorough evaluation of organ systems beyond the urinary tract is necessary.

Background: The incidence of epistaxis during nasotracheal intubation via the left nostril is more frequent than that during intubation via the right nostril. This study evaluated the effect of the reverse bevel and tip direction of the nasotracheal tube on the incidence of epistaxis during nasotracheal intubation via the left nostril. Methods: Patients undergoing right-sided maxillofacial surgery requiring left nasotracheal intubation were randomly allocated to the control (tracheal tube in the conventional direction) or reverse (a 180˚ reverse direction, with the tube bevel facing the nasal septum and the leading edge (i.e., the tip) of the bevel pointing away from the nasal septum) groups (n = 37 for both). The primary outcome was the incidence of epistaxis evaluated using videolaryngoscopy. Results: The incidence of epistaxis in the reverse group was significantly lower than that in the control group (9 [24.3%] vs. 20 [54.1%], P = 0.009; relative risk: 0.45, 95% CI [0.24, 0.85], absolute risk reduction: 29.8%, number needed to treat: 3). The severity of epistaxis was significantly lower in the reverse group (P = 0.002). The first attempt nasal passage (P = 0.027) was significantly higher in the reverse group. Postoperative nasal pain was lower (P < 0.001), and patient satisfaction was higher (P < 0.001) in the reverse group. Nasotracheal tube-related complications did not occur in either group. Conclusions The reverse bevel and tip direction of the nasotracheal tube reduced the incidence and severity of epistaxis and increased patient satisfaction among patients undergoing left nasotracheal intubation.

Fetal lower urinary tract obstruction (LUTO) is a congenital condition in which the bladder fails to excrete urine through the urethra. The primary goal of prenatal treatment for LUTO is the prevention of renal impairment and pulmonary hypoplasia. Vesico-amniotic shunt (VAS) has been the fetal intervention of choice; however, VAS has some limitations, including excretion of urine through an unphysiologic bypass and the need for postnatal corrective reoperation. In this study, we present a novel fetal intervention, a “retro-cystoscopic urethral approach,” performed on a male fetus at 20 weeks gestation diagnosed with enlarged bladder and bilateral hydronephrosis. This approach aims to dilate the narrowed urethra by inserting a urinary catheter using guidewire through a fetal cysto scope. The whole procedure was monitored under real-time ultrasonographic guidance. Despite prenatal intervention, the fetus required multiple cystocenteses, and the bladder dilation persisted.Postnatally, he was diagnosed with megacystis microcolon intestinal hypoperistalsis syndrome, a non-obstructive condition which is relatively rare in male infants. Our case emphasizes the compl exity of diagnosing LUTO during the prenatal period. Further studies exploring novel prenatal interven tions should pay more attention to candidate selection. Additionally, a thorough evaluation of organ systems beyond the urinary tract is necessary.

Fetal lower urinary tract obstruction (LUTO) is a congenital condition in which the bladder fails to excrete urine through the urethra. The primary goal of prenatal treatment for LUTO is the prevention of renal impairment and pulmonary hypoplasia. Vesico-amniotic shunt (VAS) has been the fetal intervention of choice; however, VAS has some limitations, including excretion of urine through an unphysiologic bypass and the need for postnatal corrective reoperation. In this study, we present a novel fetal intervention, a “retro-cystoscopic urethral approach,” performed on a male fetus at 20 weeks gestation diagnosed with enlarged bladder and bilateral hydronephrosis. This approach aims to dilate the narrowed urethra by inserting a urinary catheter using guidewire through a fetal cysto scope. The whole procedure was monitored under real-time ultrasonographic guidance. Despite prenatal intervention, the fetus required multiple cystocenteses, and the bladder dilation persisted.Postnatally, he was diagnosed with megacystis microcolon intestinal hypoperistalsis syndrome, a non-obstructive condition which is relatively rare in male infants. Our case emphasizes the compl exity of diagnosing LUTO during the prenatal period. Further studies exploring novel prenatal interven tions should pay more attention to candidate selection. Additionally, a thorough evaluation of organ systems beyond the urinary tract is necessary.

Background: The incidence of epistaxis during nasotracheal intubation via the left nostril is more frequent than that during intubation via the right nostril. This study evaluated the effect of the reverse bevel and tip direction of the nasotracheal tube on the incidence of epistaxis during nasotracheal intubation via the left nostril. Methods: Patients undergoing right-sided maxillofacial surgery requiring left nasotracheal intubation were randomly allocated to the control (tracheal tube in the conventional direction) or reverse (a 180˚ reverse direction, with the tube bevel facing the nasal septum and the leading edge (i.e., the tip) of the bevel pointing away from the nasal septum) groups (n = 37 for both). The primary outcome was the incidence of epistaxis evaluated using videolaryngoscopy. Results: The incidence of epistaxis in the reverse group was significantly lower than that in the control group (9 [24.3%] vs. 20 [54.1%], P = 0.009; relative risk: 0.45, 95% CI [0.24, 0.85], absolute risk reduction: 29.8%, number needed to treat: 3). The severity of epistaxis was significantly lower in the reverse group (P = 0.002). The first attempt nasal passage (P = 0.027) was significantly higher in the reverse group. Postoperative nasal pain was lower (P < 0.001), and patient satisfaction was higher (P < 0.001) in the reverse group. Nasotracheal tube-related complications did not occur in either group. Conclusions The reverse bevel and tip direction of the nasotracheal tube reduced the incidence and severity of epistaxis and increased patient satisfaction among patients undergoing left nasotracheal intubation.

Background: The incidence of epistaxis during nasotracheal intubation via the left nostril is more frequent than that during intubation via the right nostril. This study evaluated the effect of the reverse bevel and tip direction of the nasotracheal tube on the incidence of epistaxis during nasotracheal intubation via the left nostril. Methods: Patients undergoing right-sided maxillofacial surgery requiring left nasotracheal intubation were randomly allocated to the control (tracheal tube in the conventional direction) or reverse (a 180˚ reverse direction, with the tube bevel facing the nasal septum and the leading edge (i.e., the tip) of the bevel pointing away from the nasal septum) groups (n = 37 for both). The primary outcome was the incidence of epistaxis evaluated using videolaryngoscopy. Results: The incidence of epistaxis in the reverse group was significantly lower than that in the control group (9 [24.3%] vs. 20 [54.1%], P = 0.009; relative risk: 0.45, 95% CI [0.24, 0.85], absolute risk reduction: 29.8%, number needed to treat: 3). The severity of epistaxis was significantly lower in the reverse group (P = 0.002). The first attempt nasal passage (P = 0.027) was significantly higher in the reverse group. Postoperative nasal pain was lower (P < 0.001), and patient satisfaction was higher (P < 0.001) in the reverse group. Nasotracheal tube-related complications did not occur in either group. Conclusions The reverse bevel and tip direction of the nasotracheal tube reduced the incidence and severity of epistaxis and increased patient satisfaction among patients undergoing left nasotracheal intubation.

Fetal lower urinary tract obstruction (LUTO) is a congenital condition in which the bladder fails to excrete urine through the urethra. The primary goal of prenatal treatment for LUTO is the prevention of renal impairment and pulmonary hypoplasia. Vesico-amniotic shunt (VAS) has been the fetal intervention of choice; however, VAS has some limitations, including excretion of urine through an unphysiologic bypass and the need for postnatal corrective reoperation. In this study, we present a novel fetal intervention, a “retro-cystoscopic urethral approach,” performed on a male fetus at 20 weeks gestation diagnosed with enlarged bladder and bilateral hydronephrosis. This approach aims to dilate the narrowed urethra by inserting a urinary catheter using guidewire through a fetal cysto scope. The whole procedure was monitored under real-time ultrasonographic guidance. Despite prenatal intervention, the fetus required multiple cystocenteses, and the bladder dilation persisted.Postnatally, he was diagnosed with megacystis microcolon intestinal hypoperistalsis syndrome, a non-obstructive condition which is relatively rare in male infants. Our case emphasizes the compl exity of diagnosing LUTO during the prenatal period. Further studies exploring novel prenatal interven tions should pay more attention to candidate selection. Additionally, a thorough evaluation of organ systems beyond the urinary tract is necessary.

Background: The incidence of epistaxis during nasotracheal intubation via the left nostril is more frequent than that during intubation via the right nostril. This study evaluated the effect of the reverse bevel and tip direction of the nasotracheal tube on the incidence of epistaxis during nasotracheal intubation via the left nostril. Methods: Patients undergoing right-sided maxillofacial surgery requiring left nasotracheal intubation were randomly allocated to the control (tracheal tube in the conventional direction) or reverse (a 180˚ reverse direction, with the tube bevel facing the nasal septum and the leading edge (i.e., the tip) of the bevel pointing away from the nasal septum) groups (n = 37 for both). The primary outcome was the incidence of epistaxis evaluated using videolaryngoscopy. Results: The incidence of epistaxis in the reverse group was significantly lower than that in the control group (9 [24.3%] vs. 20 [54.1%], P = 0.009; relative risk: 0.45, 95% CI [0.24, 0.85], absolute risk reduction: 29.8%, number needed to treat: 3). The severity of epistaxis was significantly lower in the reverse group (P = 0.002). The first attempt nasal passage (P = 0.027) was significantly higher in the reverse group. Postoperative nasal pain was lower (P < 0.001), and patient satisfaction was higher (P < 0.001) in the reverse group. Nasotracheal tube-related complications did not occur in either group. Conclusions The reverse bevel and tip direction of the nasotracheal tube reduced the incidence and severity of epistaxis and increased patient satisfaction among patients undergoing left nasotracheal intubation.

Fetal lower urinary tract obstruction (LUTO) is a congenital condition in which the bladder fails to excrete urine through the urethra. The primary goal of prenatal treatment for LUTO is the prevention of renal impairment and pulmonary hypoplasia. Vesico-amniotic shunt (VAS) has been the fetal intervention of choice; however, VAS has some limitations, including excretion of urine through an unphysiologic bypass and the need for postnatal corrective reoperation. In this study, we present a novel fetal intervention, a “retro-cystoscopic urethral approach,” performed on a male fetus at 20 weeks gestation diagnosed with enlarged bladder and bilateral hydronephrosis. This approach aims to dilate the narrowed urethra by inserting a urinary catheter using guidewire through a fetal cysto scope. The whole procedure was monitored under real-time ultrasonographic guidance. Despite prenatal intervention, the fetus required multiple cystocenteses, and the bladder dilation persisted.Postnatally, he was diagnosed with megacystis microcolon intestinal hypoperistalsis syndrome, a non-obstructive condition which is relatively rare in male infants. Our case emphasizes the compl exity of diagnosing LUTO during the prenatal period. Further studies exploring novel prenatal interven tions should pay more attention to candidate selection. Additionally, a thorough evaluation of organ systems beyond the urinary tract is necessary.

During the coronavirus disease 2019 (COVID-19) pandemic, conclusively evaluating possible associations between COVID-19 vaccines and potential adverse events was of critical importance. The National Academy of Medicine of Korea established the COVID-19 Vaccine Safety Research Center (CoVaSC) with support from the Korea Disease Control and Prevention Agency to investigate the scientific relationship between COVID-19 vaccines and suspected adverse events. Although determining whether the COVID-19 vaccine was responsible for any suspected adverse event necessitated a systematic approach, traditional causal inference theories, such as Hill's criteria, encountered certain limitations and criticisms. To facilitate a systematic and evidence-based evaluation, the United States Institute of Medicine, at the request of the Centers for Disease Control and Prevention, offered a detailed causality assessment framework in 2012, which was updated in the recent report by the National Academies of Sciences, Engineering, and Medicine (NASEM) in 2024.This framework, based on a weight-of-evidence approach, allows the independent evaluation of both epidemiological and mechanistic evidence, culminating in a comprehensive conclusion about causality. Epidemiological evidence derived from population studies is categorized into four levels—high, moderate, limited, or insufficient—while mechanistic evidence, primarily from biological and clinical studies in animals and individuals, is classified as strong, intermediate, weak, or lacking. The committee then synthesizes these two types of evidence to draw a conclusion about the causal relationship, which can be described as “convincingly supports” (“evidence established” in the 2024 NASEM report), “favors acceptance,” “favors rejection,” or “inadequate to accept or reject.” The CoVaSC has established an independent committee to conduct causality assessments using the weightof-evidence framework, specifically for evaluating the causality of adverse events associated with COVID-19 vaccines. The aim of this study is to provide an overview of the weight-ofevidence framework and to detail the considerations involved in its practical application in the CoVaSC.