• Structural Engineering and Mechanics
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• v.27 no.1
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• pp.33-48
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• 2007

An Articulated tower is one of the compliant offshore structures connected to the sea-bed through a universal joint which is the most vulnerable location of the tower that sustains the randomly fluctuating shear stresses. The time history response of the bottom hinge shear is obtained and presented in the spectral form. The fatigue and fracture reliability assessment of the tower joint against randomly varying shear stresses have been carried out. Non-linear limit state functions are derived in terms of important random variables using S-N curve and fracture mechanics approaches. Advanced First Order Reliability Method is used for reliability assessment. Sensitivity analysis shows the influence of various variables on the hinge safety. Fatigue life estimation has been made using probabilistic approach.

• Investigative Magnetic Resonance Imaging
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• v.21 no.3
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• pp.154-161
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• 2017

Purpose: To evaluate the diagnostic performance of diffusion-weighted steady-state free precession (DW-SSFP) in comparison to diffusion-weighted echo-planar imaging (DW-EPI) for differentiating the neoplastic and benign osteoporotic vertebral compression fractures. Materials and Methods: The subjects were 40 patients with recent vertebral compression fractures but no history of vertebroplasty, spine operation, or chemotherapy. They had received 3-Tesla (T) spine magnetic resonance imaging (MRI), including both DW-SSFP and DW-EPI sequences. The 40 patients included 20 with neoplastic vertebral fracture and 20 with benign osteoporotic vertebral fracture. In each fracture lesion, we obtained the signal intensity normalized by the signal intensity of normal bone marrow (SI norm) on DW-SSFP and the apparent diffusion coefficient (ADC) on DW-EPI. The correlation between the SI norm and the ADC in each lesion was analyzed using linear regression. The optimal cut-off values for the diagnosis of neoplastic fracture were determined in each sequence using Youden's J statistics and receiver operating characteristic curve analyses. Results: In the neoplastic fracture, the median SI norm on DW-SSFP was higher and the median ADC on DW-EPI was lower than the benign osteoporotic fracture (5.24 vs. 1.30, P = 0.032, and 0.86 vs. 1.48, P = 0.041, respectively). Inverse linear correlations were evident between SI norm and ADC in both neoplastic and benign osteoporotic fractures (r = -0.45 and -0.61, respectively). The optimal cut-off values for diagnosis of neoplastic fracture were SI norm of 3.0 in DW-SSFP with the sensitivity and specificity of 90.4% (95% confidence interval [CI]: 81.0-99.0) and 95.3% (95% CI: 90.0-100.0), respectively, and ADC of 1.3 in DW-EPI with the sensitivity and specificity of 90.5% (95% CI: 80.0-100.0) and 70.4% (95% CI: 60.0-80.0), respectively. Conclusion: In 3-T MRI, DW-SSFP has comparable sensitivity and specificity to DW-EPI in differentiating the neoplastic vertebral fracture from the benign osteoporotic vertebral fracture.

• Journal of Acupuncture Research
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• v.35 no.4
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• pp.219-225
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• 2018

Background: The purpose of this study was to review whether Korean medicine treatment was effective to maintain the spinal stability and to relieve spinal symptom by reviewing medical records of 18 vertebral compression fracture patients. Methods: The subjects were 18 thoracolumbar compression fracture patients who were taken more than two lateral view x-rays of fractured vertebra from Jan, 2010 to June, 2018. They were divided into two groups: the time admitted into Department of Acupuncture & Moxibustion Medicine, Pohang Korean Medical Hospital of Daegu Hanny University from onset (Research 1) and whether or not they have a past history of osteoporosis (Research 2). Then, they were follow-up observed and compared by compression ratio and numerical rating scale (NRS) and so on. Results: The amount of weekly compression rate increase of 18 patients was 1.76% per week. According to the result of Research 1, the patients group (14 patients) who were admitted into the hospital within 1-2 weeks from getting injury was 1.88% per week whereas the patients group(4 patients) who were admitted into the hospital within 3-4 weeks from getting injury was 1.22% per week. By Research 2 result, the patients group (7 patients) who had been diagnosed as an osteoporosis patient was 2.19% per week, and those (11 patients) who had not was 1.49% per week. There was a statistical significance in the change of the amount of compression rate increase in the case of Research 1, but there was not in the case of Research 2. NRS was decreased without significant difference regardless of the time admitted into the hospital and whether or not the patients had the past history of osteoporosis. Conclusion: Considering that there were more amount of compression rate increase at 1-4 weeks from onset, it is necessary to offer treatment more actively on early time from onset. Further research is needed into the increase of compression rate by the patients' having a past history of osteoporosis or not. Given that NRS decreased without significant difference, it is assumed that Korean medicine treatment has a meaningful effect on relieving subjective symptom of patients who are diagnosed as vertebral compression fractures.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.557-562
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• 2003

The responses of the floor system of a railway bridge are investigated for fatigue life prediction of damaged members using fracture mechanics approach. Numerical analysis of the structure is performed in order to see the influence of track-structure interaction and continuity of the truss connection on the response of the bridge members. Fatigue crack growth analysis is carried through equivalent stress obtained from time-history analysis. The results of time-history analysis agree with measured responses. The fatigue propagation life increases as the curvature in the coped stringer increases.

• Clinics in Shoulder and Elbow
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• v.9 no.1
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• pp.14-19
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• 2006

The patient with a posttraumatic stiffness frequently has a history of prolonged immobilization after a traumatic event. Adhesions in the extraarticular humeroscapular motion interface may be present independently or in combination with intraarticular capsular contractures. A through history and physical examination usually reveal the cause and anatomic location of stiffness. Passive stretching exercise program is effective as a first line treatment, but manipulation under anesthesia is usually not effective because of potential complication such as fracture, tendon rupture and neurologic injury. The humeroscapular motion interface adhesion can be released either open or arthroscopically. The combined technique coupled with an aggressive rehabilitation program can provide more effective motion restoration and pain relief.

• International Journal of Railway
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• v.3 no.2
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• pp.73-82
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• 2010

Global and local behaviors of a lightly RC shear walls are investigated in this paper. For the sake of cyclic behaviors, nominal ground accelerations of 0.15 g, 0.40 g and 0.55 g which associated with natural periods of the walls are applied as listed in French CAMUS-2000 shake table test. Modified Kent & Park model, Drucker-Prager model for concrete material and $Giufr\acute{e}$-Menegotto-Pinto model for rebar are used for time history analyses using fiber/solids elements respectively. Alternatively, Eulerian beam analysis are discussed by imposing inelastic hinges at the most possible plastic hinge location using modified Takeda's trilinear model with stiffness reduction. Relative displacements, base shears, bending moments of 5-story shear building with 36-tons of mass under bi-lateral seismic excitation are extracted and compared with EC-8, PS-92 and KBC-09 provisions. Multi-scaled degradation process; material damage, elemental fracture and structural failure in turn is discussed in the view of numerical accuracy, efficiency and limitation depending on three different model-based analyses.

• Restorative Dentistry and Endodontics
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• v.39 no.1
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• pp.56-62
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• 2014

A tooth with primary endodontic disease that demonstrates a periodontal defect might be extracted because of misdiagnosis as severe periodontal disease or a vertical root fracture. The aim of this case report was to demonstrate the long-term survival of endodontically treated teeth, which had been initially considered unsavable. With meticulous evaluation including the patient's dental history, clinical and radiographic examinations, teeth with primary endodontic lesions could be differentiated and saved after proper root canal treatment. Pain history, vitality test, and radiographic examinations, as well as a general periodontal condition check with periodontal probing on an affected tooth, might be the key methods to differentiate endodontic pathosis from that of periodontal disease.

• Journal of Korean Neurosurgical Society
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• v.58 no.4
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• pp.346-349
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• 2015

Objective : To investigate the value of lumbar bone mineral density (BMD) in fracture risk assessment (FRAX) tool. Methods : One hundred and ten patients aged over 60 years were enrolled and divided into 2 groups as non-osteoporotic vertebral fracture (OVF) and OVF groups. The 10-year-risk of major osteoporotic vertebral fracture of each group was calculated by FRAX tool with femoral and lumbar spine BMDs to compare the usefulness of lumbar spine BMD in prediction of OVF. The blood level of osteocalcin and C-terminal telopeptide (CTX) as markers of activities of osteoblast and osteoclast, respectively were analyzed using the institutional database. Results : In the OVF group, the ratio of patients with previous fracture history or use of glucocorticoid was higher than those in non-OVF group (p=0.000 and 0.030, respectively). The levels of T-score of femur neck and lumbar spine in OVF group were significantly lower than those in non-OVF group (p=0.001 and 0.000, respectively). The risk of OVF in FRAX using femur BMD in non-OVF and OVF groups was $6.7{\pm}6.13$ and $11.4{\pm}10.06$, respectively (p=0.007). The risk of using lumbar BMD in the 2 groups was $6.9{\pm}8.91$ and $15.1{\pm}15.08$, respectively (p=0.002). The areas under the receiver operator characteristic curve in the FRAX risk with lumbar and femur neck BMD were 0.726 and 0.684, respectively. The comparison of osteocalcin and CTX was not significant (p=0.162 and 0.369, respectively). Conclusion : In our study, the 10-year risk of major osteoporotic fracture in the OVF group of our study was lower than the recommended threshold of intervention for osteoporosis. Hence, a lower threshold for the treatment of osteoporosis may be set for the Korean population to prevent OVF. In the prediction of symptomatic OVF, FRAX tool using lumbar spine BMD may be more useful than that using femur neck BMD.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.7 no.2
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• pp.98-104
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• 2014

Purpose: To evaluate the incidence of deep vein thrombosis (DVT) before hip fracture by duplex color Doppler ultrasonography. Materials and Methods: From June 2013 to May 2014, 27 patients who had agreed to perform color Doppler ultrasonography before hip fracture surgery were evaluated for the incidence of DVT. Patients who had history of DVT were excluded. Five patients were men and 19 patients were women. The mean age was 74.3 years old (41-87). There were 15 cases of femoral neck fracture, 11 cases of intertrochanteric fractures and one case of acetabular fracture. Surgical intervention underwent within 48 hours from admission and duplex color Doppler ultrasonography was carried out at the day of admission. Results: DVT occurred in six cases (22.2%). Four cases (14.8%) occurred in proximal deep vein and two cases (7.4%) occurred in distal deep vein. The mean period of immobilization was longer in patients who had DVT. But there was no significant difference. The mean age was 79 years old (75-87) in patients who had DVT and 72 years old (65-86) in patients who had not. There was significant difference (p=0.038). Conclusion: The incidence of DVT which was diagnosed by duplex color Doppler ultrasonography before hip fracture surgery was relatively high (22.2%). So it is necessary to undergo duplex color Doppler ultrasonography more aggressively to rule out DVT before hip fracture surgery.

• Korean Journal of Bronchoesophagology
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• v.9 no.1
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• pp.96-100
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• 2003

Retrophayngeal hematomas frequently develop in patients who had cervical vertebra fracture. The hematoma develops in the space between buccopharyngeal fascia and prevertebral fascia. But it rarely causes severe airway obstruction. We recently treated a patient who had dyspnea and dysphagia due to a retropharyngeal hematoma without any significant trauma history. First, tracheostomy was performed to maintain the airway. Then, incision and drainage was done under suspension laryngoscope. This case shows the fact that a retropharyngeal hematoma can result in severe airway obstruction even after a minor trauma.