Purpose: This study was conducted to develop a convolutional neural network (CNN) algorithm that can diagnose cervical foraminal stenosis using oblique radiographs and evaluate its accuracy. Materials and Methods: A total of 997 patients who underwent cervical MRI and cervical oblique radiographs within a 3-month interval were included. Oblique radiographs were labeled as “foraminal stenosis” or “no foraminal stenosis” according to whether foraminal stenosis was present in the C2–T1 levels based on MRI evaluation as ground truth. The CNN model involved data augmentation, image preprocessing, and transfer learning using DenseNet161. Visualization of the location of the CNN model was performed using gradient-weight class activation mapping (Grad-CAM). Results: The area under the curve (AUC) of the receiver operating characteristic curve based on DenseNet161 was 0.889 (95% confidence interval, 0.851–0.927). The F1 score, accuracy, precision, and recall were 88.5%, 84.6%, 88.1%, and 88.5%, respectively.The accuracy of the proposed CNN model was significantly higher than that of two orthopedic surgeons (64.0%, p<0.001; 58.0%, p<0.001). Grad-CAM analysis demonstrated that the CNN model most frequently focused on the foramen location for the determination of foraminal stenosis, although disc space was also frequently taken into consideration. Conclusion A CNN algorithm that can detect neural foraminal stenosis in cervical oblique radiographs was developed. The AUC, F1 score, and accuracy were 0.889, 88.5%, and 84.6%, respectively. With the current CNN model, cervical oblique radiography could be a more effective screening tool for neural foraminal stenosis.

Apolipoprotein E (apoE) plays a role in various physiological functions including lipid transport, synaptic plasticity, and immune modulation.Epidemiological studies suggest that the apoE4 allele increases the risk of post-traumatic sequelae. This study was performed to investigate regionspecific effects of the apoE4 isoform on post-traumatic neurodegeneration. Two focal brain injuries were introduced separately in the motor cortex and hippocampus of apoE4 knock-in, apoE3 knock-in, apoE knockout, and wild-type (WT) mice. Western blotting showed that the expression levels of pre-synaptic and post-synaptic markers at the recovery stage were lower in the hippocampal injury core in apoE4 mice, compared with apoE3 and WT mice. Fast glial activation (determined by immunohistochemistry with glial fibrillary acidic protein, ionized calcium binding adaptor molecule 1, and cluster of differentiation 45 antibodies) was characteristic of apoE4 mice with hippocampal injury penumbra. apoE4-specific changes were not observed after cortical injury. The intensity of microglial activation in the hippocampus was inversely correlated with the volume of injury reduction on sequential magnetic resonance imaging examinations, when validated using matched samples. These findings indicate that the effects of the interaction between apoE4 and focal brain damage are specific to the hippocampus. Manipulation of inflammatory cell responses could be beneficial for reducing post-traumatic hippocampal neurodegeneration in apoE4 carriers.

Background/Aims: Several prediction models for evaluating the prognosis of nonmetastatic resected pancreatic ductal adenocarcinoma (PDAC) have been developed, and their performances were reported to be superior to that of the 8th edition of the American Joint Committee on Cancer (AJCC) staging system. We developed a prediction model to evaluate the prognosis of resected PDAC and externally validated it with data from a nationwide Korean database. Methods: Data from the Surveillance, Epidemiology and End Results (SEER) database were utilized for model development, and data from the Korea Tumor Registry System-Biliary Pancreas (KOTUS-BP) database were used for external validation. Potential candidate variables for model development were age, sex, histologic differentiation, tumor location, adjuvant chemotherapy, and the AJCC 8th staging system T and N stages. For external validation, the concordance index (C-index) and time-dependent area under the receiver operating characteristic curve (AUC) were evaluated. Results: Between 2004 and 2016, data from 9,624 patients were utilized for model development, and data from 3,282 patients were used for external validation. In the multivariate Cox proportional hazard model, age, sex, tumor location, T and N stages, histologic differentiation, and adjuvant chemotherapy were independent prognostic factors for resected PDAC. After an exhaustive search and 10-fold cross validation, the best model was finally developed, which included all prognostic variables. The C-index, 1-year, 2-year, 3-year, and 5-year time-dependent AUCs were 0.628, 0.650, 0.665, 0.675, and 0.686, respectively. Conclusions The survival prediction model for resected PDAC could provide quantitative survival probabilities with reliable performance. External validation studies with other nationwide databases are needed to evaluate the performance of this model.

General anesthesia is associated with a risk for postoperative pulmonary complications. The risk is even higher in patients with chronic respiratory failure, and postoperative mortality rates are high. Proper perioperative anesthetic management is important in such patients. Therefore, it is essential to optimize the patient’s physical status before anesthesia and to determine the optimal anesthesia technique based on the pre-anesthesia evaluation of the patient’s pulmonary function. We successfully performed abdominal surgery under spinal anesthesia in a patient with severe chronic respiratory failure.

Apolipoprotein E (apoE) plays a role in various physiological functions including lipid transport, synaptic plasticity, and immune modulation.Epidemiological studies suggest that the apoE4 allele increases the risk of post-traumatic sequelae. This study was performed to investigate regionspecific effects of the apoE4 isoform on post-traumatic neurodegeneration. Two focal brain injuries were introduced separately in the motor cortex and hippocampus of apoE4 knock-in, apoE3 knock-in, apoE knockout, and wild-type (WT) mice. Western blotting showed that the expression levels of pre-synaptic and post-synaptic markers at the recovery stage were lower in the hippocampal injury core in apoE4 mice, compared with apoE3 and WT mice. Fast glial activation (determined by immunohistochemistry with glial fibrillary acidic protein, ionized calcium binding adaptor molecule 1, and cluster of differentiation 45 antibodies) was characteristic of apoE4 mice with hippocampal injury penumbra. apoE4-specific changes were not observed after cortical injury. The intensity of microglial activation in the hippocampus was inversely correlated with the volume of injury reduction on sequential magnetic resonance imaging examinations, when validated using matched samples. These findings indicate that the effects of the interaction between apoE4 and focal brain damage are specific to the hippocampus. Manipulation of inflammatory cell responses could be beneficial for reducing post-traumatic hippocampal neurodegeneration in apoE4 carriers.

BACKGROUND: We aimed to confirm the long-term effect of patellar nonresurfacing (patellar decompression) in preventing anterior knee pain after total knee arthroplasty (TKA) and to investigate the possible complications. METHODS: Among patients who underwent primary TKA after being diagnosed as having advanced osteoarthritis (Kellgren-Lawrence grade 4) at our institution from January 2004 to December 2010, 121 patients who were followed up for more than 7 years were included in this study. Patients who underwent TKA with and without patellar decompression were classified as the study group and control group, respectively. A clinical knee rating score was used to compare the postoperative clinical outcomes between groups. To identify complications after patellar decompression, simple radiographs (weight-bearing anteroposterior and lateral views, patella in 30° and 45° axial views, and whole scanogram) were taken during follow-up. RESULTS: There were no complications such as patellar fracture, osteonecrosis, and subluxation. At 2 years after surgery, the prevalence of anterior knee pain was 12.7% and 18.0% in the study group and control group, respectively (p = 0.42), and the number of patients with patellofemoral osteoarthritis grade II or over was lower in the study group (p = 0.03). At 7 years after surgery, the prevalence of anterior knee pain was 18.3% and 24.0% in the study group and control group, respectively (p = 0.45), and there was no statistically significant intergroup difference in the number of patients with patellofemoral osteoarthritis grade II or over (p = 0.11). CONCLUSIONS Patellar nonresurfacing TKA reduces anterior knee pain in the early postoperative period. The procedure can be considered a relatively safe option with fewer complications; however, its effectiveness appears to decrease over time.

PURPOSE: To evaluate the clinical outcomes of small incision lenticule extraction (SMILE) for the treatment of myopia with corneal opacity. METHODS: Thirteen eyes of 13 patients with corneal opacities who underwent SMILE were retrospectively studied. Uncorrected distance visual acuity, spherical equivalence, efficacy index, and safety index were noted at 3 months after the procedure. The density and area of the corneal opacities were measured and compared preoperatively and 3 months postoperatively. RESULTS: All eyes had preoperative corneal opacities within the lenticule formation areas. The mean area and density of corneal opacities were 0.72 ± 0.33 mm2 and 52.46 ± 15.74, respectively. All procedures were uneventful and no intraoperative complications were observed. At 3 months after the procedure, the efficacy and safety indices were 1.01 ± 0.15, and 1.05 ± 0.10, respectively, and the mean densities and areas of corneal opacities were 46.85 ± 14.56 (p = 0.038) and 0.70 ± 0.36 mm2 (p = 0.776), respectively. CONCLUSIONS: The SMILE procedure was effective and safe for the correction of myopic patients with corneal opacities.
Corneal Opacity ; Humans ; Intraoperative Complications ; Myopia ; Retrospective Studies ; Visual Acuity

PURPOSE: To evaluate non-alcoholic fatty pancreas disease severity on ultrasound (US-determined NAFPD) as a risk factor for coronary heart disease (CHD) and to evaluate its predictive value for intermediate/high CHD risk compared with US-determined non-alcoholic fatty liver disease (US-determined NAFLD) severity. MATERIALS AND METHODS: A retrospective analysis of 544 young adults, aged 18–40 years, was performed. NAFPD and NAFLD were classified as absent, mild, moderate, and severe. CHD risk was calculated using the Framingham Risk Score (FRS). Correlation, multivariate logistic regression, and receiver operating characteristic curve analyses were used to compare the predictive performance. RESULTS: FRS increased with increasing US-determined NAFPD severity (r = 0.624, p < 0.001), with a concomitant increase in the odds ratio for intermediate/high CHD risk. There was no difference between the predictive performance of US-determined NAFLD and NAFPD severities for intermediate/high CHD risk (p = 0.17). The combination of US-determined NAFPD and NAFLD severities significantly improved the differentiation between intermediate and high CHD risk (predictive value, 0.807; p < 0.001). CONCLUSION US-determined NAFPD severity was well-correlated with FRS and associated with the prevalence of intermediate/high CHD risk. The combination of US-determined NAFPD and NAFLD severities may be useful for predicting CHD risk.

BACKGROUND: Substantial variation exists in the reported rates of postoperative venous thromboembolism (VTE) following total knee arthroplasty (TKA) in the Asian population. This retrospective study aimed to compare the early postoperative VTE incidence between patients managed with epidural anesthesia and those managed by general anesthesia at the time of TKA. METHODS: We reviewed 589 cases of unilateral primary TKA performed between January 2011 and June 2014. We selected epidural versus general anesthesia groups as the main anesthetic choices, with postoperative patient-controlled analgesia. All the patients underwent deep vein thrombosis (DVT) computed tomography angiography on postoperative day 7. The incidence of DVT and pulmonary thromboembolism (PTE) was evaluated and compared between epidural and general anesthesia. RESULTS: The overall incidence of VTE was 8.0% in the two groups together. The incidence did not differ between the groups. The odds ratio in the generalized estimation equations analysis showed a higher incidence of DVT and PTE in the epidural group; however, this result was not statistically significant. Although, the odds ratio for age showed that the risk of developing DVT and PTE increased 1.12 times per year. CONCLUSIONS: Total VTE incidence was not significantly different between patients who underwent general anesthesia and those who underwent epidural anesthesia for TKA. A prospective multicenter study is required to evaluate the nature of the Korean VTE status in major orthopedic surgeries, and to prepare guidelines and protocols for medical prophylaxis for DVT and PTE in Korea.
Analgesia, Patient-Controlled ; Anesthesia, Epidural ; Anesthesia, General* ; Angiography ; Arthroplasty, Replacement, Knee* ; Asian Continental Ancestry Group ; Humans ; Incidence* ; Korea ; Odds Ratio ; Orthopedics ; Prospective Studies ; Pulmonary Embolism ; Retrospective Studies* ; Venous Thromboembolism* ; Venous Thrombosis

PURPOSE: To compare the clinical outcome of combined small incision lenticule extraction and collagen cross-linking (SMILE Xtra) with SMILE. METHODS: This study included 30 eyes from 15 patients who had undergone SMILE Xtra and a random sample of 30 eyes from 15 patients receiving SMILE alone during the same period. We obtained the following parameters from all patients: uncorrected (UDVA) and corrected distance visual acuity (CDVA), spherical equivalent (SE), efficacy and safety index, and corneal high-order aberrations. RESULTS: The SMILE Xtra group had higher preoperative SE and thinner central corneal and residual stromal bed thickness and optic zone diameter compared to the control group (p < 0.001). At 6 months, there was no significant difference in UDVA or CDVA between the two groups. The efficacy indices were 0.97 ± 0.16 and 1.05 ± 0.17 in the SMILE Xtra and control groups, respectively (p = 0.044), and there was no significant difference in safety index between the two groups during the follow-up period. Total corneal high-order aberrations numbered 2.59 ± 0.56 and 2.02 ± 0.41 in the SMILE Xtra and control groups, respectively (p < 0.001), and there was significant increase in spherical aberration and horizontal corneal aberration in both groups compared to preoperative results. Corneal haze was observed in 20% of eyes in the SMILE Xtra group, and no complication such as corneal ectasia was observed during the follow-up period. CONCLUSIONS: SMILE Xtra had good early clinical outcome compared to SMILE alone. It appears that SMILE Xtra can be a good modality when the cornea is thin or SE is high. However, postoperative corneal haze should be considered.
Collagen* ; Cornea ; Dilatation, Pathologic ; Follow-Up Studies ; Humans ; Visual Acuity