• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.244-247
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• 2005

Although several artificial disc designs have been developed for the treatment of discogenic low back pain and used clinically, biomechanical change with its implantation seldom studied. To evaluate the effect of artificial disc implantation on the biomechanics of lumbar spinal unit, nonlinear three-dimensional finite element model of L1-L5, S1 was developed and strain and stress of vertebral body and surrounding spinal ligaments were predicted. Intact osteoligamentous L1-L5, S1 model was created with 1-mm CT scan of a volunteer and known material property of each element were applied. This model also includes the effect of local muscles which was modeled with pre-strained spring elements. The intact model was validated with reported biomechanical data. Two models implanted with artificial discs, SB Charite or Prodisc, at L4/5 via anterior approach were also developed. The implanted model predictions were compared with that of intact model. Angular motion of vertebral body, force on spinal ligaments, facet joint contact force with $2\sim12$ Nm flexion-extension moment.

• Journal of Acupuncture Research
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• v.15 no.2
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• pp.301-310
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• 1998

Infrared thermographic imaging visualizes noninvasively various abnormal condition by detecting the skin temperature. As the imaging represents the objective condition by the changes in blood flow under the control of autonomic nervous system, it is used to diagnosis and monitor the lumboscral radiculopathy. And asymmetry is important in the diagnosis of disc herniation. The most common type of disc herniation occurs psoterolaterally. This frequently causes nerve root compression leading to a radiculopathy in the distribution of the involved nerve root, most of which also provoke the asymmetric changes in thermography. Central disc herniation, which accounts for 5% to 35% of disc herniation, is typically associated with low back pain. But radiculopathy is usually abscent unless central disc heriniaton is large enough to cause compression of the cauda equina. To evalute the diagnostic value of the thermographic imaging in the diagnosis of central disc herniation, the imaging of 15 normal subjects and 48 patients with central disc herniation documented by CT scan were analyzed. The patients had either bilateral radiculophathy or no radiculopathy. The imaging of patient group with non rediculopathy did not show any significant thermal difference to control. While bilateral radiculopathy group reveled hypothermic pattern compared twith control. Thermal difference between left and right side did not present any significance in non radiculopathy group but hypothermia in bilateral radiculopathy group. Large herniation group demonstrated hyperthemic pattern while the others showed no significant change. Cranial caudal thermal difference did not show any difference between experiment groups. These results shows that infrared thermographic imaging can be used central disc herniation with bilateral radiculopathy, while it seems to little useful on the diagnosis of non radiculopathic disc herniation.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.562-570
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• 2010

This study was conducted to estimate the number of disc cutter consumption and to predict amount of disc cutters when a shield TBM(Tunnel Boring Machine) of the Han Riverbed Tunnel was applied. In fact, it is almost impossible to change the machine after starting the excavation using the shield TBM method. Therefore, it is important to design an appropriate equipment in the shield method - an efficiency choice of the operation equipment plays a key role in the shield tunnel processing. For the above reason, the disc cutter consumption prediction is quite important so that the detailed analysis is required. A number of disc cutter consumption was predicted by the three methods, viz. KOMATSU, MITSUBISHI and NTNU. In addition, the predicted results were compared with field data. The prediction of disc cutter consumption showed that 237 for KOMATSU, 501 for MITSUBISHI, and 634 for NTNU, respectively. However, a total number of 1,263 disc cutter consumption were investigated during the tunnel construction. It was found that there was a huge difference between the predicted and real values of the disc cutter consumption. The more detailed investigation showed that the disc cutter was worn out bluntly in the northbound tunnel, meanwhile it was worn out sharply in the southbound tunnel. In particular, the disc cutter consumption in the southbound tunnel was increased rapidly because of rear abrasion for remaining mucks in the chamber.

• Journal of Veterinary Clinics
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• v.39 no.6
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• pp.334-341
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• 2022

A decrease in the paraspinal muscle cross-sectional area (CSA) and functional cross-sectional area (FCSA) are associated with low back pain and disc herniation in humans. This study examined whether chronicity or lateralization of disc herniation affects the CSA and FCSA of the paraspinal muscles. The CSA and FCSA of the paraspinal muscles between the 12th and 13th thoracic vertebrae were measured in 31 dogs with intervertebral disc herniation (IVDH). The muscle CSA and FCSA were evaluated by dividing the values of the body weight, spinal disc CSA, and spinal canal CSA to offset the differences in body type between subjects. In the chronic IVDH group, the ratio of the paraspinal muscle CSA divided by the body weight was significantly lower, and fat infiltration in the paraspinal muscle was significantly higher than in the acute group. The lateralization of the disc herniation was significantly related to the changes in the paraspinal muscle CSA. In the right-sided disc herniation group, right epaxial muscle CSA was significantly reduced compared to the left-sided disc herniation group. The change in the paraspinal muscle might be a helpful indicator to localize less obvious disc pathologies and target the search for the pathology responsible for disc-related symptoms in dogs.

• Transactions of the Society of Information Storage Systems
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• v.2 no.3
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• pp.196-200
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• 2006

We are developing a phase change etching technology using an inorganic photoresist of GeSbTe film which is the recording material of the phase change disc. A selective etching phenomenon between amorphous and crystalline states can be utilized with an alkaline etchant. Phase-change pits could be formed using this technique, in which the etching selectivity is strongly dependent on the concentration of the etchant. The degree of etching was investigated by the transmittance between crystalline and amorphous films after the wet-etching. The pits patterned on the disc could be observed by AFM after wet-etching.

• Journal of radiological science and technology
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• v.30 no.4
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• pp.407-417
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• 2007

The purpose of this study is to determine whether change of the lumbar intervertebral disc diameters and size is a risk factor for development of lumbar disc lesion and this changes are associated with aging. The L4-5 and L5-S1 intervertebral disc diameters and size were measured in 50 normal subjects and 50 low back pain patients in the age range $20{\sim}60$ by MRI. The data were analysed with independent t-test to differentiation between normal subjects and low back patients. We also analysed with one-way ANOVA, Pearson correlation and simple linear regression to differentiate between different age ranges. This study has shown that older subjects of both normal and low back pain patients have significantly larger transverse diameters and sizes of the L4-5 and L5-S1 intervertebral disc, compared with those of younger subjects. In addition, low back pain patients's disc sizes were larger than normal subjects but there was statistically no significant difference. The measurement of the intervertebral disc size can be considered as a clinically useful method for diagnosis of the low back pain and aging of the intervertebral disc. However, further study should be conducted to establish normal value of intervertebral disc size on large number of subjects.

• Journal of Korean Medicine Rehabilitation
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• v.28 no.4
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• pp.33-41
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• 2018

Objectives The purpose of this study is to analyze the effects of Korean Medicine treatment on lumbar disc herniation (LDH) and predictive factors associated with disc resorption by magnetic resonance imaging (MRI). Methods A retrospective study was carried out in 79 lumbar disc herniation patients who had visited Haeundae Jaseng Hospital of Korean Medicine. Patients' diagnosis was based on MRI. MRI was performed on two or more occasions and patients were received Korean Medicine treatment within the period. The volume of each herniated disc was measured three-dimensionally and patient characteristics, interval between MRIs, herniated disc level, disc herniation type, disc migration, intactness of posterior longitudinal ligament (PLL), initial volume of herniated disc, modic change, disc resorption rate were statistically analyzed. Results The mean volumes of herniated discs before Korean Medicine treatment and after Korean Medicine treatment were $1,547.81{\pm}598.15mm^3$ and $947.06{\pm}335.28mm^3$, respectively. The mean resorption rate was $35.7{\pm}16.3%$. Disc extent, intactness of PLL and initial volume of herniated discs were significantly correlated with resorption rate (p=0.003, p=0.001 and p=0.024, respectively). Conclusions Korean Medicine treatment is an effective conservative treatment for lumbar disc herniation. Factors such as disc migration, intactness of PLL, initial volume of herniated disc have a significant association with disc resorption rate.

• The Korean Journal of Pain
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• v.34 no.4
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• pp.447-453
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• 2021

Background: Provocative discography (PD) is a test that is useful in diagnosing discogenic pain (DP). In this study, to diagnose DP, we used a posterolateral approach of needle placement and followed pressure criteria laid down by the Spine Intervention Society. The aim was to identify the correlation between magnetic resonance imaging (MRI) findings (desiccation, high intensity zone and change in shape and size of the disc) and the results of PD. Methods: Records of 50 patients who underwent PD for DP were analyzed. A total of 109 PDs were performed, with 54 suspect and 55 control discs. Alternate pain generators were ruled out. Results: A total of 35 suspect discs were positive on PD. The mean disc pressure in the suspect disc was 31.9 ± 7.9 psi (range, 15-44). Of the 50 patients who underwent PD, 35 had positive MRI findings. A significant positive correlation was found only between disc desiccation and discography result (r = 0.6, P < 0.001). Logistic regression analysis revealed that only desiccation successfully predicted the result of discography (OR = 26.5, P < 0.001); a high intensity zone and a disc protrusion/extrusion had an OR 2.3 and 1.24, respectively. Disc desiccation of Pfirmann grade 3 or more had a sensitivity and specificity of 0.93 and 0.64 respectively in identifying painful discs; the positive likelihood ratio was 2.58 while the negative likelihood ratio was 0.11. Conclusions: In patients with DP, disc desiccation is the most useful MRI feature that predicts a painful disc on PD.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.481-487
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• 2011

This paper provides a comparison between finite element analysis results and test data of rupture disc. Rupture disc is safety device of high pressure equipment. Rupture disc of solid rocket motor is a device to control rupture pressure. Rupture discs were made of AISI 316L. By the elastic-plastic analysis, the stress limit of rupture discs were compared to the test results. The results can be used to control the rupture pressure by the change of the disc size.

• The Journal of Korea CHUNA Manual Medicine
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• v.2 no.1
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• pp.85-92
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• 2001

Objectives : To study the cervical lordosis and disc degeneration in neck pain patients with or without low back pain. Subjects. The study was composed of 57 neck pain patients with low back pain(LBP group) and 40 neck pain patients without low back pain(Non-LBP group). Methods : Radiographic measures of spinal lordosis(cervical and lumbar) and disc degeneration were collected, and statistically analyzed. Results: LBP group showed a significant increase in cervical lordotic angle as compared with Non-LBP group, whereas no significant change in cervical disc degeneration. A relationship was found between cervical and lumbar disc degeneration in LBP $group({\gamma}-0.3064)$. Conclusions : The findings from this study suggest that the curvature of the cervical spine is related to the subject's low back pain.