Biomechanical comparison of bone staple fixation methods with suture material for median sternotomy closure using 3D-printed bone models.

AIM: To compare the biomechanical properties of three different sternal closure techniques in a 3D-printed bone model of a sternum from a 30-kg dog. METHODS: Median sternotomy was performed on a total of 90 three-dimensional (3D) copies of a polycarbonate (PC) model of a sternum, generated from the CT images of the sternum of a 30-kg German Shepherd dog. Three different methods were used to repair the sternotomies: polydioxanone suture (group PDS, n = 30), stainless steel bone staples (group SS, n = 30), and nitinol bone staples (group NS, n = 30). Each repair method was tested by applying tensile force in one of three ways (longitudinally, laterally, or torsionally) resulting in a sample size of n = 10 for each repair method-loading combination. In all experiments, the loads at 1-mm and 2-mm gap formation, failure, and the displacement at the failure point were measured. RESULTS: In lateral distraction and longitudinal shear tests, NS and SS staple repairs required application of significantly greater force than PDS across all displacement criteria (1 and 2 mm). NS exhibited significantly greater failure load than PDS. In torsion tests, NS required significantly greater application of force compared to SS or PDS at all displacement criteria (1 and 2 mm) and exhibited a greater failure load than PDS. In terms of displacement at failure point, PDS suture showed more displacement than SS or NS across all experiments (laterally, longitudinally, torsionally). CONCLUSIONS: In this study, bone staples were mechanically superior to PDS suture in median sternotomy closure using 3D-printed bone model in terms of 1-mm, 2-mm displacement loads, and displacement at failure. NS had a higher failure load than PDS under lateral, longitudinal, and torsional distraction. CLINICAL RELEVANCE: These study results imply that bone staples can be considered as an alternative surgical method for median sternotomy closure in dogs.

Parkinson's disease and skin cancer risk: a nationwide population-based cohort study in Korea.

BACKGROUND: Previous studies have reported that patients with Parkinson's disease (PD) have a significantly lower risk of cancer. Studies reporting prevalence of skin cancers in Parkinson's disease mostly involve Caucasians. OBJECTIVE: A nationwide population-based study was conducted to determine the risk of skin cancer in patients diagnosed with PD in Korea. METHODS: Data obtained from National Health Insurance Claims records were used to retrieve information about 70 780 patients with newly diagnosed PD between January 2010 and December 2015. The control group included 353 900 sex- and age-matched patients without PD. In this nationwide population-based cohort study, we investigated the association between PD and skin cancer. RESULTS: The overall hazard ratio (HR) of skin cancers in patients with PD was 1.169 (95% CI, 1.005-1.359) compared with non-PD group. Among patients with PD, males aged above 65 had a 2.8-fold increase in the risk for melanoma development than the non-PD group (HR, 2.825; 95% CI, 1.395-5.721). In addition, female PD patients aged above 65 years showed a 1.3-fold increase in non-melanoma skin cancer risk than the non-PD group (HR, 1.305; 95% 1.073-1.589). CONCLUSION: Compared with the general population, Korean patients diagnosed with PD had a greater risk of skin cancer. Especially, male patients aged 65 years and above, and diagnosed with PD had a significant risk of melanoma development compared with control.

Association between smoking and Behçet's disease: a nationwide population-based study in Korea.

BACKGROUND: There have been conflicting results about the association between Behçet's disease and smoking. Smoking has been reported to be a protective factor for Behçet's disease, whereas smoking may have a role in triggering Behçet's disease. OBJECTIVES: The aim of this study was to investigate the incidence of Behçet's disease in Korea according to smoking status using nationwide population data. METHODS: We analysed clinical data from individuals 20 years of age and older who received a health examination arranged by the Korean national insurance programme between 2009 and 2012. The incidence of Behçet's disease was analysed according to smoking status reported by individuals during their health examination. Newly diagnosed cases of Behçet's disease were identified using claims data from baseline to the date of diagnosis or until 31 December 2016. RESULTS: The risk of Behçet's disease was lower in current smokers compared with never-smokers regardless of the amount and duration of smoking. The decreased risk of Behçet's disease in current smoker persisted after adjusting for age, sex, regular exercise, drinking status, BMI, diabetes mellitus, hypertension, and dyslipidaemia, history of stroke and/or history of ischaemic heart diseases. LIMITATIONS: Genetic susceptibility or family history of Behçet's disease was not considered. CONCLUSIONS: This study found a decreased incidence of Behçet's disease in current smokers compared with never-smokers. Further investigation of the pathophysiology responsible for the negative association between smoking and Behçet's disease is needed.

Incidence, prevalence, and mortality of Adamantiades-Behçet's disease in Korea: a nationwide, population-based study (2006-2015).

BACKGROUND: The epidemiology of Adamantiades-Behçet's disease varies among ethnic populations worldwide. Trends in the incidence of Adamantiades-Behçet's disease have not been investigated based on the Korean National Health Insurance database. OBJECTIVES: This study investigated the incidence and mortality of Adamantiades-Behçet's disease by age using nationwide population data in Korea. METHODS: A nationwide population-based cohort study was performed using the Korean National Health Insurance Claims Database from 2006 to 2015. The incidence of Adamantiades-Behçet's disease was calculated by age, sex, calendar year and habitat. And comorbid metabolic diseases were also analysed in patients with Adamantiades-Behçet's disease. RESULTS: The annual incidence of Adamantiades-Behçet's disease per 100 000 person-years was 3.976 (2.587 for males and 5.373 for females) from 2006 to 2015. The incidence of Adamantiades-Behçet's disease peaked among people in their 40s (6.561 per 100 000 person-years). Incidence was significantly higher in subjects with comorbid metabolic conditions, such as diabetes mellitus, hypertension and dyslipidemia. The mortality rate per 1000 person-years increased with age in patients with Adamantiades-Behçet's disease. CONCLUSIONS: This study showed the incidence, prevalence and mortality of Adamantiades-Behçet's disease. Metabolic conditions increased the risk of Adamantiades-Behçet's disease among Koreans.

Prevalence of tinnitus according to temporomandibular joint disorders and dental pain: The Korean National Population-based Study.

Some studies have reported that temporomandibular joint disorder (TMD) is related to tinnitus. However, there is no study of the relationship and prevalence of dental pain and tinnitus. We evaluated the associations between the prevalence of tinnitus and TMD and dental pain by analysing the Korean national health survey. We analysed totally 11 745 participants. The presence of tinnitus, TMD symptoms and dental pain was surveyed by self-assessment questionnaires from all the participants. Multivariable regression analysis was applied to acquire odds ratios (OR) and 95% confidence intervals (CI). The prevalence of tinnitus was higher in the subjects with dental pain (21.1%), TMD (22.5%) and both symptoms (31.2%) than subjects without those symptoms (19.6%). After adjusting for all covariates, subjects with TMD had tinnitus 1.6 times more than subjects without TMD. In the subanalysis, age group more than 65 years, women, and obese subjects had tinnitus more than men, age group <65, and non-obese subjects, respectively. TMD alone and both dental pain and TMD were associated with tinnitus (OR = 1.389 and 95% CI 1.054-1.832 and 2.206 and 1.637-2.974, respectively). Subjects with TMD had more tinnitus than subjects without TMD. Moreover, subjects with dental pain in addition to TMD had increased prevalence of tinnitus than TMD alone.

Single-stage cell-based cartilage repair in a rabbit model: cell tracking and in vivo chondrogenesis of human umbilical cord blood-derived mesenchymal stem cells and hyaluronic acid hydrogel composite.

OBJECTIVE: Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) have gained popularity as a promising cell source for regenerative medicine, but limited in vivo studies have reported cartilage repair. In addition, the roles of MSCs in cartilage repair are not well-understood. The purpose of this study was to investigate the feasibility of transplanting hUCB-MSCs and hyaluronic acid (HA) hydrogel composite to repair articular cartilage defects in a rabbit model and determine whether the transplanted cells persisted or disappeared from the defect site. DESIGN: Osteochondral defects were created in the trochlear grooves of the knees. The hUCB-MSCs and HA composite was transplanted into the defect of experimental knees. Control knees were transplanted by HA or left untreated. Animals were sacrificed at 8 and 16 weeks post-transplantation and additionally at 2 and 4 weeks to evaluate the fate of transplanted cells. The repair tissues were evaluated by gross, histological and immunohistochemical analysis. RESULTS: Transplanting hUCB-MSCs and HA composite resulted in overall superior cartilage repair tissue with better quality than HA alone or no treatment. Cellular architecture and collagen arrangement at 16 weeks were similar to those of surrounding normal articular cartilage tissue. Histological scores also revealed that cartilage repair in experimental knees was better than that in control knees. Immunohistochemical analysis with anti-human nuclear antibody confirmed that the transplanted MSCs disappeared gradually over time. CONCLUSION: Transplanting hUCB-MSCs and HA composite promote cartilage repair and interactions between hUCB-MSCs and host cells initiated by paracrine action may play an important role in cartilage repair.

Atopic dermatitis is inversely associated with hepatitis B antigen positivity: a population-based cohort study.

BACKGROUND: No clear association between hepatitis B virus (HBV) infection and atopic dermatitis (AD) has been established. Some studies have reported that subjects with HBV had an increased risk of atopy; other studies reported an inverse association between HBV seropositivity and allergic diseases. OBJECTIVE: We evaluated the association between AD and hepatitis B antigen (HBsAg) positivity using Korean National Health and Nutrition Examination Survey data. METHODS: In total, 14 776 participants aged >19 years were included in the analysis. Multiple logistic regression analyses were used to evaluate the odds ratio of HBsAg positivity in association with AD and asthma. RESULTS: The prevalence of HBsAg positivity was lower in individuals with AD than in those without AD (mean [SE], 0.7% [0.4] vs. 3.7% [0.2]; P < 0.001). However, HBsAg positivity was not significantly associated with asthma (3.7% [0.2] vs. 2.8% [0.8]; P < 0.001). HBsAg positivity decreased the risk of AD significantly (OR = 0.223; 95% CI = 0.069-0.72). CONCLUSIONS: This study demonstrates an inverse association between AD and HBsAg positivity using a nationwide, population-based, cross-sectional health examination and survey.

The cutoff value of ossification of posterior longitudinal ligament (OPLL) for early diagnosis of myelopathy using somatosensory evoked potential in cervical OPLL patients.

STUDY DESIGN: Retrospective study. OBJECTIVES: The objective of this study was to find out whether ossification of posterior longitudinal ligament (OPLL) characteristics, including size, shape and subtype, can be used to diagnose myelopathy using somatosensory evoked potential (SEP) in cervical OPLL patients. SETTING: Yonsei University College of Medicine, Seoul, Korea. METHODS: We retrospectively reviewed the medical records of 153 cervical OPLL patients who underwent SEP study. OPLL anterior-posterior (AP) diameter, area and involved longitudinal vertebral level were measured. OPLL was classified into subtypes according to longitudinal continuity and shape. Correlation analysis and receiver operating curve were used. RESULTS: Tibial SEP latency was significantly correlated with OPLL AP diameter (P=0.001), diameter occupying ratio (P=0.019), area (P=0.007), area occupying ratio (P=0.008), involved longitudinal vertebral level (P=0.028) and space available for the spinal cord (P=0.019). The cutoff values that were diagnostic for SEP prolongation suggesting myelopathy were 4.91 mm for OPLL AP diameter, 6.02 mm for space available for the spinal cord, 44.5% for diameter occupying ratio, 63.4 mm2 for area, 36.1% for area occupying ratio and level 2 for the involved longitudinal vertebral level. CONCLUSIONS: Our results revealed that tibial SEP latency was significantly correlated with OPLL size and suggested cutoff values of OPLL diameter (4.91 mm, 44.5%) and area (63.4 mm2, 36.1%) for early diagnosis of myelopathy. These results can help to establish treatment plans.

Association of lipid parameters and insulin resistance with bone health in South Korean adolescents.

UNLABELLED: This study investigated the association between lipid profiles and insulin resistance and bone mineral content (BMC) in Korean adolescents and found that BMC was inversely associated with triglyceride (TG) and homeostasis model assessment of insulin resistance (HOMA-IR). This association did not differ according to obesity status in either boys or girls. INTRODUCTION: To prevent future osteoporosis, it is important to identify factors that affect bone health in adolescents as well as adults. This study aimed to examine the association between lipid profiles and insulin resistance and BMC in Korean adolescents. METHODS: Data from 706 boys and 621 girls, who participated in the Korea National Health and Nutrition Examination Survey from 2008 to 2011, were analyzed. Lipid profiles were measured, and HOMA-IR was calculated to assess insulin resistance. BMC was measured for the total femur, femur neck, and lumbar spine by using whole-body dual-energy X-ray absorptiometry (DXA). RESULTS: TG level and HOMA-IR were negatively correlated with BMC at all three sites in boys. In girls, TG level showed a negative correlation with BMC at the femur neck and lumbar spine, and HOMA-IR was negatively associated with BMC at the femur neck only. These inverse associations did not differ according to obesity status in either sex. Adjusted means of BMC at the three sites in boys tended to decrease in the higher tertile groups of TG and HOMA-IR, and the adjusted means of BMC for the total femur in girls tended to decrease in the higher tertile groups of TG and HOMA-IR. CONCLUSIONS: BMC was inversely associated with TG and HOMA-IR in Korean adolescents, and this association was more pronounced in boys. This association did not differ according to obesity status in either sex.

Association between dental pain and depression in Korean adults using the Korean National Health and Nutrition Examination Survey.

The purpose of this study was to evaluate the relationships between the prevalence of depression and dental pain using a well characterised, nationally representative, population-based study. This study analysed data from the 2012 Korea National Health and Nutrition Examination Survey (n = 4886). Oral health status was assessed using the oral health questionnaire, and oral examination was performed by trained dentists. Depression was defined as the participant having been diagnosed as depression during the previous year. Logistic regression was applied to estimate adjusted odds ratios (AOR) and 95% confidence intervals (CI), controlling for a range of covariates. Results demonstrated that participants included in 'root canal treatment is necessary' showed higher prevalence of self-reported dental pain; in particular, participants with depression presented more dental pain than those without depression. After adjusting for sociodemographic factors, self-reported dental pain increased in participants with depression. The AOR (95% CI) for having self-reported dental pain was 1·58 (1·08-2·33) in dentists' diagnosis of no dental pain/depression group, 1·62 (1·32-1·98) in dentists' diagnosis of dental pain/no depression group and 2·84 (1·10-7·37) in dentists' diagnosis of dental pain/depression group. It was concluded that depression was associated with dental pain after adjustment for potential confounders in Korean adults. Thus, dentists should consider the possible presence of psychopathology when treating patients with dental pain.

Microbiological and clinical characteristics of bacteraemia caused by the hypermucoviscosity phenotype of Klebsiella pneumoniae in Korea.

Hypermucoviscous (HV) isolates of Klebsiella pneumoniae have been linked to virulence potential in experimental infections. We examined 33 isolates of K. pneumoniae from patients with bacteraemia for the HV phenotype on agar culture, and determined their virulence potential by screening for capsular (K) serotype by polymerase chain reaction and the presence of seven virulence factor genes. Fourteen (42·4%) isolates expressed the HV phenotype and 11 of these were serotype K1 or K2; these serotypes were not identified in HV-negative isolates. The genes rmpA, rmpA2, aerobactin, wabG and allS were significantly more frequent in HV than non-HV isolates. Multilocus sequence typing identified 21 sequence types (ST), eight of which were found in HV-positive isolates and the clonal relatedness of isolates of the most frequent types (ST23 and ST11) from different hospitals was confirmed by pulsed-field gel electrophoresis. The HV phenotype was more associated with community-acquired infection with a lower frequency of fatal underlying illness, but with significantly more focal infections, notably liver abscesses. Clinicians should be aware of such clinical impacts of the HV phenotype.

Diagnostic value of CA125 as a predictor of recurrence in advanced ovarian cancer.

PURPOSE: The aim of this study was to establish the guidelines for detecting early recurrences of advanced epithelial ovarian cancer by use of the CA-125 level. MATERIALS AND METHODS: Eighty-five of the patients who met the inclusion criteria were enrolled in this study. The authors examined 25 incremental changes of CA125 from one to 25 IU/ml, and compared the CA-125 value with other prognostic factors. Increases in the CA-125 level from the nadir level were expressed as CA-125- increments. RESULTS: Among the 25 increments, a CA-125-8 (eight IU/ml) was selected as the predictor that was the most efficient and time-effective. CA-125-8 had a sensitivity of 91.5%, a specificity of 84.6%, a positive predictive value of 93.1%, a negative predictive value of 81.5%, an efficiency of 89.4%. and a median lead-time of 68.5 days (p <0.0001). CONCLUSION: The authors suggest the incremented CA-125-8 as a predictor of recurrent advanced ovarian cancer.

Effects of self-ligating brackets on the surfaces of stainless steel wires following clinical use: AFM investigation.

In orthodontic treatment, the frictional force between the archwire and bracket reduces the effectiveness of orthodontic treatment. The frictional force is affected not only by the geometry of the self-ligating brackets but also by physical changes between the bracket slots and archwire surfaces during sliding movement. This study examined quantitatively the effect of self-ligating treatments on the surfaces of stainless steel (SS) archwires during tooth movement in vivo by atomic force microscopy. Orthodontic 0.019″ × 0.025″ SS archwires after clinical use with the first bicuspid-extraction treatment were employed using the Damon 3MX(®) SS self-ligating brackets, Clippy-C(®) ceramic self-ligating brackets, and Kosaka(®) SS brackets. Intact SS archwires were used as the control group. All SS archwires after clinical use showed severe scratches and significantly higher roughness caused by frictional interactions between the brackets and archwires (p < 0.0001 vs. control). The descending order of surface roughness was the SS archwires treated, with ceramic self-ligating brackets, with conventional SS brackets, and with SS self-ligating brackets (p < 0.001). These findings suggest that an orthodontic treatment with SS self-ligating brackets may require smaller orthodontic forces than that with ceramic self-ligating brackets or conventional SS brackets.

Potential effects of tooth-brushing on human dentin wear following exposure to acidic soft drinks.

This study used scanning electron microscopy and atomic force microscopy to examine the short-term potential effects of brushing time and the start-time of tooth-brushing after demineralization on primary dentin wear in vitro. Thirty-six noncarious primary central incisors were assigned to 12 experimental groups. Exposure to cola drinks was used to initiate the demineralization process. Three brushing times (5, 15 and 30 s) and four start-times of brushing (0, 30, 60 and 120 min) after an erosive attack were used for the abrasion process. Tooth-brushing the softened dentin surface led to increases in the open tubular fraction and microstructural changes on the dentin surface. Brushing immediately after exposure to cola resulted in the greatest irreversible dentin loss, whereas brushing 60 or 120 min after pretreatment resulted in the least irreversible dentin loss. However, brushing time had no effect on the irreversible loss of dentin wear. Based on these experimental results, tooth-brushing should be performed at least 60 min after consuming a cola drink to achieve the desired tooth cleaning and avoid the introduction of surface lesions on dentin.

Characteristics of stroke mechanisms in patients with medullary infarction.

BACKGROUND: Few studies have focused on the mechanisms underlying medullary infarctions. Our aim in this study was to investigate stroke mechanisms in patients with medullary infarctions and to determine the clinical, radiological and laboratory characteristics of these patients with different underlying stroke etiologies. METHODS: Consecutive patients with medullary infarction were analysed. Stroke mechanisms were classified as large artery disease (LAD), cardiogenic embolism (CE), small vessel disease (SVD), arterial dissection or undetermined etiology. Clinical, radiological and laboratory factors were analysed according to the location of the lesion and stroke mechanisms. RESULTS: A total of 77 patients were enrolled in this study. Amongst them, 53 (68.8%) patients had lateral medullary infarction (LMI), 22 (28.6%) had medial medullary infarction (MMI), and the remaining 2 (2.6%) had hemimedullary infarction. In both LMI and MMI patients, LAD was the most frequently encountered stroke mechanism. Arterial dissection was the second most common cause followed by SVD and CE in patients with LMI, whereas SVD was more frequently observed (P < 0.001) and dissection and CE were less prevalent (P < 0.001 and P = 0.024, respectively) in MMI than in LMI. Regarding differences amongst stroke etiologies, patients with dissection were younger and had a significantly lower incidence of metabolic syndrome (P = 0.002 and P = 0.009, respectively) than patients with LAD and SVD. Patients in the LAD (19/34, 60%) and dissection groups (12/14, 75%) had abnormal perfusion-weighted MRI (PWI) findings, whereas all patients with SVD (9/9) had normal PWI findings (P < 0.001). CONCLUSIONS: Stroke mechanisms in medullary infarction differ between LMI and MMI. Clinical and radiological characteristics, especially PWI features, are helpful in discriminating the etiologies of stroke in these patients.

Validation of a Korean version of the quality-of-life profile for spine deformities (QLPSD) in patients with adolescent idiopathic scoliosis.

OBJECTIVE: We aimed to evaluate the reliability and validity of the adapted Korean version of the Quality-of-Life Profile for Spine Deformities (QLPSD) questionnaire. PATIENTS AND METHODS: English version of QLPSD was translated into Korean according to previously published guidelines. The Korean version of the QLPSD questionnaire and the Korean version of the SRS-22 was sent to 120 consecutive idiopathic scoliosis patients wearing braces recruited from the outpatient clinic. Reliability assessment and construct validity were evaluated. RESULTS: The intraobserver reliability of all items in the questionnaire had a kappa statistic of agreement greater than 0.6. The QLPSD showed good test/re-test reliability (ICC = 0.815). The internal consistency of Cronbach's α was found to be very good (α = 0.918). The Korean version of QLPSD showed a significant correlation with the SRS-22 total score (p<0.001, r=-0.811) and single SRS-22 domains scores. CONCLUSIONS: The adapted Korean version of the QLPSD was successfully translated and showed good measurement properties. As such, it is considered suitable for outcome assessments in Korean-speaking patients with idiopathic scoliosis.

Peripheral compressing artifacts in brain tissue from stereotactic biopsy with sidecutting biopsy needle: a pitfall for adequate glioma grading.

AIMS: The stereotactic brain biopsy is an essential diagnostic procedure in modern neurologic patient management. A side-cutting biopsy needle is one of the most widely used needle types. Recently we found a characteristic tissue artifact named "peripheral compressing artifact" in the brain tissues biopsied using a side-cutting needle of Leksell's system. We investigate prevalence, possible cause and its clinical implication of this type of artifact. MATERIALS AND METHODS: We examined the biopsies from 80 patients (44 cases of gliomas, 13 lymphomas, 7 germ cell tumors, 2 other tumors, 1 metastatic carcinoma, 4 non-tumorous conditions such as demyelinating disease and 8 non-diagnostic) in the stereotactic biopsy group with a suspected brain tumor, who underwent a stereotactic brain biopsy using side-cutting needle of Leksell's system. We also evaluated 16 cases of open brain biopsies without Leksell's system as a control group. RESULTS: The artifact is a semi-circular or band-like tissue compression in the periphery of the biopsied tissue. This artifact was found in 30 (37.5%) out of 80 cases and 57 (11.9%) out of 477 biopsied pieces. It might be produced during rotating of the inner cannula of the biopsy needle. Histologically, it might be misinterpreted as "hypercellular", "spindle", "well circumscribed", or rarely as "pseudopalisading" especially in glioma. CONCLUSIONS: Awareness of this artifact would help making the appropriate pathological diagnosis for glioma.