External ventricular drainage (EVD) is a common procedure performed in neurosurgical field. The purpose of this study was to introduce the linear intracranial calcification formed along EVD tract and to investigate its incidence, predisposing factors, and clinical impact. A total of 59 patients who underwent EVD insertion over a 1-year period were included in this study. The clinical factors and radiographic features between the occurrence and the non-occurrence groups were analyzed to investigate the predisposing factors and clinical impact related to the linear intracranial calcification in EVD tract. The linear intracranial calcification following EVD insertion occurred in 7 patients (11.9%). Among various risk factors assessed, only usage of bone dust (p =0.003) had contributed to linear intracranial calcification with statistical significance in univariate logistic regression analysis. Housefield unit (HU) scale was different between calcification (872.57 ± 46.15 HU) and EVD catheter (169.00 ± 61.35 HU). This study indicates that using bone dust for sealing a burr hole is the only predisposing factor for linear intracranial calcification formed in EVD tract.
Catheters ; Causality* ; Drainage* ; Dust ; Humans ; Incidence ; Logistic Models ; Risk Factors

To evaluate the predisposing factors and characteristics of the steinstrasse after ESWL and to suggest the proper management of it, we analyzed 1,144 urolithiasis patients who were managed by ESWL with the second generation lithotripter, Siemens Lithostar, at Seoul National University Hospital from March 1989 to October 1995. Steinstrasse developed in 72 patients with the incidence of 6.3% after ESWL. As the risk factor for developing steinstrasse after ESWL, stone size and volume significantly influenced the development of steinstrasse (p<0.01, by student t-test), and multiple stones induced steinstrasse more frequently than single stones (p<0.05, by chi-square test). Stones located at renal pelvis induced more steinstrasse after ESWL than calyceal stones or ureter stones t<0.05, by chi-square test). Clinically, 61.1% of the patients who developed steinstrasse didn't have any symptoms or upper tract changes. Nineteen steinstrasse (26.4%) were resolved spontaneously without any intervention, with the median duration of 12 days after detection of the steinstrasse. In 51 steinstrasse which was not resolved spontaneously or with severe symptoms, ESWL was performed resulting in successful resolution in 94.1% of the patients. These results suggest that expectancy could be the first line strategy of the management of steinstrasse, and repeated ESWL could be recommended for patients refractory to expectancy and patients with severe symptoms.
Causality ; Humans ; Incidence ; Kidney Pelvis ; Risk Factors ; Seoul ; Ureter ; Urolithiasis

We expirenced multiple hepatocellular adenomatosis, which was proved by pathology, in 38 years old man who had no prior history of predisposing factors. The radiologic findings were different by the size of tumor mass and intratumoral hemorrhage. Ultrasound demonstrated inhomogeneous hyperechoic large mass in segment 5 of right lobe and hyperechoic or isoechoic multiple small nodules in right lobe. Computed tomography demonstrated low density mass without contrast enhacement. Central high density is noted in hemorrhagic portion. Magnetic resonance T1-weighted image demonstrated high signal intensity in mass and hemorrhagic portion. T2-weighted image demonstrated slightly high signal intensity in mass portion, high signal intensity in hemorrhagic portionand double-layered peripheral rim. Gradient echo image well demonstrated inhomogenesity of mass.
Causality ; Hemorrhage ; Pathology ; Ultrasonography

Diarrhea ; Cities ; Epidemiologic Causality

BACKGROUND: Spontaneous pneumomediastinum is an uncommon, benign, self-limited disorders that usually occurs in young adults without any apparent precipitating factors or disease. The purpose of this study was to review our experience in dealing with this entity and describe a reasonable course of assessment and management. MATERIAL AND METHOD: A retrospective case series was conducted to identify adults patients with SPM who were diagnosed and treated in a single institution between 2001 and 2005. RESULT: Fifteen patients were identified who included 14 men and 1 women with a mean age of 26 years. Presenting symptoms were chest pain in 12 patients (80%), dyspnea in 5 patients (33%), and throat discomfort in 4 patients (26%). Two cases were associated with use of inhalational drugs and 3 cases were associated with exercise. The predisposing factors were asthma, excessive exercise, and vomiting in spontaneous pneumomediastinum. The physical findings were subcutaneous emphysema in 10 patients (77%). Chest radiography and computerized tomography were the diagnostic methods in all cases with CT scan revealing six cases with associated pulmonary abnormalities. Esophagogram and flexible bronchoscopy were selectively used. Fifteen patients (100%) were admitted to the hospital. Their mean hospital stay was 3 days. All patients were conservatively treated. In a follow-up of 3 years no complications or recurrences were observed. CONCLUSION: Most simple spontaneous pneumomediastinum cases were benign diseases and most of them (77%) had shown typical chest pain, dyspnea and subcutaneous emphysema. Inhalational drug use was not a major cause of SPM; however, increased use of bronchoinhalers was a suspicious cause of SPM.
Adult ; Asthma ; Bronchoscopy ; Causality ; Chest Pain ; Dyspnea ; Female ; Follow-Up Studies ; Humans ; Length of Stay ; Male ; Mediastinal Emphysema* ; Mediastinum ; Pharynx ; Precipitating Factors ; Radiography ; Recurrence ; Retrospective Studies ; Subcutaneous Emphysema ; Thorax ; Tomography, X-Ray Computed ; Vomiting ; Young Adult

No abstract available.
Arthritis, Rheumatoid* ; Causality* ; Humans ; Methotrexate*

No abstract available.
Causality* ; Humans ; Infant, Newborn* ; Pneumothorax*

Estimating the actual real-world effectiveness of the vaccine is an essential part of the post-marketing evaluation. This regression discontinuity design (RDD) using observational data is designed to quantify the effect of an intervention when eligibility for the intervention is based on a defined cutoff as age, making it suited to estimate vaccine effects. This approach can avoid the high cost and ethical issues; overcome difficulties in the organization and practice process in randomized controlled trials, which leads to a higher level of causal inference evidence and more realistic results. Here, we describe key features of RDD in general, and then specific scenarios, with examples, to illustrate that RDD are an essential tool for advancing our understanding of vaccine effects.
Causality ; Humans ; Vaccine Efficacy ; Vaccines

PURPOSE: To investigate the risk factors and the factors affecting surgical and visual outcomes of rhegmatogenous retinal detachment in patients under 40 years of age. METHODS: This retrospective study included 88 patients (96 eyes) diagnosed with rhegmatogenous retinal detachment that were followed up for more than 3 months postoperatively. Patients were categorized into 3 groups according to age. The etiologic risk factors and the primary anatomical and functional success rates were analyzed. Preoperative factors that could affect postoperative visual acuity and primary anatomical outcome, such as subretinal strands and proliferative vitreoretinopathy (grade C or worse), were analyzed. RESULTS: Myopia more severe than -4.0 diopters was the most common predisposing factor in all 3 groups. Anatomical success rates and functional success rates were not significantly different among the groups. Prevalence of macular detachment and proliferative vitreoretinopathy were highest in group 1. The presence of subretinal strands was highest in group 2 and proliferative vitreoretinopathy was highest in group 1. Patients with preoperative subretinal strands showed a lower primary anatomical success rate in group 1 and poor postoperative visual acuity in groups 1 and 2. Patients with proliferative vitreoretinopathy had poor postoperative visual acuity however there was no significant difference in primary anatomical success rate among the groups. CONCLUSIONS: Proliferative vitreoretinopathy did not affect the anatomical success rate but did affect visual outcome in rhegmatogenous retinal detachment in patients under age 40. Subretinal strands contributed to a lower anatomical success rate and poorer visual outcome in such patients that were under age 18.
Causality ; Humans ; Myopia ; Prevalence ; Retinal Detachment* ; Retrospective Studies ; Risk Factors ; Visual Acuity ; Vitreoretinopathy, Proliferative ; Vitreous Detachment

PURPOSE: To investigate the risk factors and the factors affecting surgical and visual outcomes of rhegmatogenous retinal detachment in patients under 40 years of age. METHODS: This retrospective study included 88 patients (96 eyes) diagnosed with rhegmatogenous retinal detachment that were followed up for more than 3 months postoperatively. Patients were categorized into 3 groups according to age. The etiologic risk factors and the primary anatomical and functional success rates were analyzed. Preoperative factors that could affect postoperative visual acuity and primary anatomical outcome, such as subretinal strands and proliferative vitreoretinopathy (grade C or worse), were analyzed. RESULTS: Myopia more severe than -4.0 diopters was the most common predisposing factor in all 3 groups. Anatomical success rates and functional success rates were not significantly different among the groups. Prevalence of macular detachment and proliferative vitreoretinopathy were highest in group 1. The presence of subretinal strands was highest in group 2 and proliferative vitreoretinopathy was highest in group 1. Patients with preoperative subretinal strands showed a lower primary anatomical success rate in group 1 and poor postoperative visual acuity in groups 1 and 2. Patients with proliferative vitreoretinopathy had poor postoperative visual acuity however there was no significant difference in primary anatomical success rate among the groups. CONCLUSIONS: Proliferative vitreoretinopathy did not affect the anatomical success rate but did affect visual outcome in rhegmatogenous retinal detachment in patients under age 40. Subretinal strands contributed to a lower anatomical success rate and poorer visual outcome in such patients that were under age 18.
Causality ; Humans ; Myopia ; Prevalence ; Retinal Detachment* ; Retrospective Studies ; Risk Factors ; Visual Acuity ; Vitreoretinopathy, Proliferative ; Vitreous Detachment