• Journal of Korean Neurosurgical Society
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• v.48 no.3
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• pp.285-287
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• 2010

Although the spontaneous disappearance or decrease in size of a herniated disc is well known, that of a large extruded disc has rarely been reported. This paper reports a case of a spontaneous regression of a large lumbar disc extrusion. The disc regressed spontaneously with clinical improvement and was documented on a follow up MRI study 6 months later. The literature is reviewed and the possible mechanisms of spontaneous disc regression are discussed.

• The Korean Journal of Pain
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• v.23 no.1
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• pp.51-54
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• 2010

A herniated intervertebral disc is the most common type of soft tissue mass lesion within the lumbar spinal canal. Magnetic resonance imaging (MRI) is a useful tool for the assessment of patients with lower back pain and radiating pain, especially intervertebral disc herniation. MRI findings of intervertebral disc herniation are typical. However, from time to time, despite an apparently classic history and typical MRI findings suggestive of disc herniation, surgical exploration fails to reveal any lesion of an intervertebral disc. Our patient underwent lumbar disc surgery with the preoperative diagnosis of lumbar disc herniation; however, nothing could be found during the surgical procedure, except a swollen nerve root.

• The Korean Journal of Pain
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• v.22 no.1
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• pp.99-103
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• 2009

We studied the historical changes of intervertebral disc displacement using magnetic resonance imaging. The phenomenon of the spontaneous regression of herniated discs is well known. The case of a 40-years-old male presenting with a large disc herniation at L5-S1, experiencing severe sciatic pain, and having the straight leg raising test positive at 25 degrees is presented. The extruded disc was documented by clinical examination. He was treated conservatively with epidural steroid injection (ESI), medication, physical therapy and self-exercise and reevaluated in 10 weeks later, 30 and 1 year. Large extruded disc can be treated successfully by physical therapy with ESI. However, the degeneration and the dehydration of disc result in decrease of disc height. Consequently, the regression of extruded disc might have been due to the resorption and the dehydration.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.796-799
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• 2002

The stress of the rotating disc with several types of hole was investigated in detail in this paper. Maximum circumferential stress of rotating disc by changing hole shape with same area, were studied using FEM. The results obtained were as follows: 1. The disc which rotates at high speed is subjected to circumferential stress remarkably. 2. When the number of circular holes in rotating disc is four, stress reduction effect is maximum. 3. When shape of holes in rotating disc is cylindrical elongated hole, maximum circumferential stress of the rotating disc decreased most.

• Journal of Korean Neurosurgical Society
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• v.38 no.3
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• pp.196-201
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• 2005

Objective : Among upper lumbar disc herniations, L1-2 disc herniations are especially rare. We present the specific clinical features of L1-2 disc herniation and compared results of different surgical options. Methods : The authors undertook a retrospective single institution review of the patients who underwent surgery for L1-2 disc herniation. Thirty patients who underwent surgery for isolated L1-2 disc herniations were included. Results : Buttock pain was more frequent than anterior or anterolateral thigh pain. Standing and/or walking intolerance was more common than sitting intolerance. The straight leg raising test was positive only in 15 patients [50%]. Iliopsoas weakness was more frequent than quadriceps weakness. Percutaneous discectomy group demonstrated worse outcome than laminectomy group or lateral retroperitoneal approach group. Conclusion : Standing and/or walking intolerance, positive femoral nerve stretch test, and iliopsoas weakness can be useful clues to the diagnosis of L1-2 disc herniation. Posterior approach using partial laminectomy and medial facetectomy or minimally invasive lateral retroperitoneal approach seems like a better surgical option for L1-2 disc herniation than percutaneous endoscopic discectomy.

• Korean Journal of Veterinary Research
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• v.59 no.3
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• pp.165-169
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• 2019

A 6-year-old Dachshund was presented with acute, non-localized pain without neurological dysfunction. Radiography revealed multiple calcifications of intervertebral discs and narrowing of disc space in the thoracolumbar region. Computed tomography and magnetic resonance imaging revealed calcified disc-like material entrapped in the left extraforaminal area and showed a displaced nerve root. Fenestration and removal of the extruded disc material were performed in a routine manner. Histopathological examination showed degenerative disc materials with severe calcification both in the nucleus pulposus and around the annulus fibrosis. Based on imaging, surgical, and histopathologic results, the dog was diagnosed with far lateral lumbar disc extrusion.

• Imaging Science in Dentistry
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• v.36 no.2
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• pp.73-79
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• 2006

Purpose : To describe the MRI findings of the antero-superior attachment of the disc in patients with internal derangement. Materials and Methods : One hundred fifty-six MR images from 40 normal subjects and 55 abnormal subjects were classified into three study groups of normal, anterior disc displacement with reduction and anterior disc displacement without reduction. On both closed- and open-mouth proton density sagittal images, the depiction of the antero-superior attachment of the disc and its demarcation from the disc were evaluated in three cuts of lateral, central and medial one thirds of the condyle. Results : The depiction of antero-superior attachment was more frequent by the order of normal, anterior disc displacement with reduction and anterior disc displacement without reduction groups, and the significant differences were found on lateral cut of the closed images and lateral and central cuts of the open images. In study for the demarcation between the antero-superior attachment and the disc the lateral cut of the closed images and all three cuts of the open images showed significant differences. Conclusion : Open images are useful to show the difference in depiction of the antero-superior attachment of the disc among the TMJ groups.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.315-320
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• 2004

Swing check valves are the most common type of check valve in nuclear power plant and need to be operated property to perform their functions and to keep the valve internals stable. However, for a swing check valve disc to remain stable, the opening characteristics should be identified and the upstream flow velocity should be enough to hold the disc fully open and without motion. Thus it is necessary to develop a model for predicting the flow velocity for a given disc opening. In the present study, the disc positions with mean flow velocity were measured for 3 inch and 6 inch swing check valves. Comparison of the measurements with the existing models showed that the models underestimate the mean flow velocity for a given disc position. Therefore, the existing model for predicting swing check valve disc position was improved with the realistic disc impingement area perpendicular to the flow stream and the experimental data. The result showed that the improved model with the best estimate of kb = 0.04 predicts well the disc openings of 6 inch swing check valve, especially in the low velocity region. For better prediction of the disc opening at high flow velocity, however, it is recommended to develop a kb correlation with the disc angle.

• Journal of Korean Neurosurgical Society
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• v.44 no.5
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• pp.327-333
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• 2008

Objective: The purpose of this study is to verify the usefulness of the rabbit model for disc degeneration study. Materials: The L1-L2, L2-L3, L3-L4. or L4-L5 lumbar intervertebral disc (IVD) of 9 mature male New Zealand White rabbits were injured by inserting a 16-gauge needle to a depth of 5 mm in the left anterolateral annulus fibrosus while leaving L5-L6 IVD uninjured. Three other rabbits also received intradiscal injections of rabbit disc cells transfected with adenovirus and bone morphogenetic protein-2 (ad-BMP-2) at L4-L5 in addition to injury by 16-gauge needle at the L1-L2 level. Using digitized radiographs, measurements of IVD height were made and analyzed by using the disc height index (DHI). Magnetic resonance imaging (MRI) scans of the injured discs, injected discs, and uninjured L5-L6 discs were performed at 15 weeks post surgery and compared with preoperative MRI scans. Results: All twelve rabbits showed consistent results of disc degeneration within 15 weeks following annular puncture. DHIs of injured discs were significantly lower than that of the uninjured L5-L6 discs (p<0.05). The mean value of disc degeneration grade of injured discs was significantly higher than that of uninjured discs (p<0.05). The injection of disc cell transfected with ad-BMP-2 did not induce disc regeneration at 15 weeks after injection. Conclusion: This study showed that the injured disc had a significant change in DHI on simple lateral radiograph and disc degeneration grade on MRI scans within 15 weeks in all rabbits. Rabbit annular puncture model can be useful as a disc degeneration model in vivo.

• Journal of Korean Neurosurgical Society
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• v.47 no.1
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• pp.26-29
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• 2010

Objective: Recurrent lumbar disc herniation has been reported to occur in 5% to 15% of surgically treated primary lumbar disc herniation cases. We investigated the molecular biologic characteristics of primary herniated discs and recurrent discs to see whether the recurrent discs has the similar biological features with primary herniated discs. Methods: Primary hemiated disc and recurrent disc cells were obtained by discectomy of lumbar disc patients and cells were isolated and then taken through monolayer cultures. We compared chondrogenic and osteogenic mRNA gene expression, and western blot between the two groups. Results: The mRNA gene expression of recurrent disc cells were increased 1.47* times for aggrecan, 1.38 times for type I collagen, 2.04 times for type II collagen, 1.22 times for both Sox-9 and osteocalcin, and 1.31 times for alkaline phosphatase, respectively, compared with the primary herniated lumbar disc cells (*indicates p < 0.05). Westem blot results for each aggrecan, type I collagen, type II collagen, Sox-9, osteocalcin, and alkaline phosphatase were similar between the primary herniated disc cells and recurrent disc cells. Conclusion: These results indicate that the recurrent disc cells have similar chondrogenic and osteogenic gene expression compared to primary herniated disc cells. Therefore, we assumed that the regeneration of remaining discs could fill the previous discectomy space and also it could be one of the factors for disc recurrence especially in the molecular biologic field.