155 research outputs found

    Clinical Effectiveness of Percutaneous Epidural Neuroplasty According to the Type of Single-Level Lumbar Disc Herniation : A 12-Month Follow-Up Study

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    Objective: To determine whether the outcomes of percutaneous epidural neuroplasty (PEN) are influenced by the type of lumbar disc herniation (LDH) and evaluate the effectiveness of PEN in patients with single-level LDH. Methods: This study included 430 consecutive patients with single-level LDH who underwent PEN. Before treatment, the LDH type was categorized as bulging, protrusion, extrusion, and sequestration, while Pfirrmann grades were assigned according to imaging findings. Visual analog scale (VAS) scores for back and leg pain and success rates (Odom's criteria) were assessed at 1, 3, 6, and 12 months after treatment. Results: The mean preoperative VAS scores for back and leg pain were 6.90 and 4.23, respectively; these decreased after PEN as follows : 2.25 and 1.45, respectively, at 1 month; 2.61 and 1.68, respectively, at 3 months; 2.28 and 1.48, respectively, at 6 months; and 2.88 and 1.48, respectively, at 12 months (p70% patients with extrusion or sequestration. Patients with Pfirrmann grades 1-3 (14.0-21.5%) showed a significantly higher rate of subsequent surgery than those with Pfirrmann grade 0 (4.9%; p<0.05). Conclusion: Our findings suggest that PEN is an effective treatment for back and leg pain caused by single-level LDH, with the outcomes remaining unaffected by the LDH type.ope

    Efficacy of a Novel Annular Closure Device After Lumbar Discectomy in Korean Patients : A 24-Month Follow-Up of a Randomized Controlled Trial

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    Objective: Lumbar discectomy is an effective treatment for lumbar disc herniation (LDH); however, up to 2-18% of patients with LDH have experienced recurrent disc herniation. The purpose of this study was to evaluate the efficacy of a novel annular closure device (ACD) for preventing LDH recurrence and re-operation compared with that of conventional lumbar discectomy (CLD). Methods: In this prospective randomized controlled trial, we compared CLD with discectomy utilizing the Barricaidยฎ (Intrinsic Therapeutics, Inc., Woburn, MA, USA) ACD. Primary radiologic outcomes included disc height, percentage of preoperative disc height maintained, and re-herniation rates. Additional clinical outcomes included visual analog scale (VAS) scores for back and leg pain, Oswestry Disability Index (ODI) scores, and 12-item short-form health survey (SF-12) quality of life scores. Outcomes were measured at preoperation and at 1 week, 1, 3, 6, 12, and 24 months postoperation. Results: Sixty patients (30 CLD, 30 ACD) were enrolled in this study. At 24-month follow-up, the disc height in the ACD group was significantly greater than that in the CLD group (11.4ยฑ1.5 vs. 10.2ยฑ1.2 mm, p=0.006). Re-herniation occurred in one patient in the ACD group versus six patients in the CLD group (ฯ‡2=4.04, p=0.044). Back and leg VAS scores, ODI scores, and SF-12 scores improved significantly in both groups compared with preoperative scores in the first 7 days following surgery and remained at significantly improved levels at a 24-month follow-up. However, no statistical difference was found between the two groups. Conclusion: Lumbar discectomy with the Barricaidยฎ (Intrinsic Therapeutics, Inc.) ACD is more effective at maintaining disc height and preventing re-herniation compared with conventional discectomy. Our results suggest that adoption of ACD in lumbar discectomy can help improve the treatment outcome.ope

    ์‹ฌํ์†Œ์ƒ์ˆ ์— ๋Œ€ํ•œ ์ˆ˜ํ•™์  ๋ชจ๋ธ๋ง ๊ธฐ๋ฐ˜์˜ ์ ‘๊ทผ

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    ํ•™์œ„๋…ผ๋ฌธ(๋ฐ•์‚ฌ) -- ์„œ์šธ๋Œ€ํ•™๊ต๋Œ€ํ•™์› : ๊ณต๊ณผ๋Œ€ํ•™ ํ˜‘๋™๊ณผ์ • ๋ฐ”์ด์˜ค์—”์ง€๋‹ˆ์–ด๋ง์ „๊ณต, 2021.8. ์ด์ •์ฐฌ.์‹ฌํ์†Œ์ƒ์ˆ ์˜ ์ƒ๋ฆฌํ•™์  ํ˜„์ƒ์— ๋Œ€ํ•œ ์ดํ•ด๋ฅผ ์œ„ํ•ด ์‹ฌํ์†Œ์ƒ์ˆ ์˜ ๋ฉ”์ปค๋‹ˆ์ฆ˜๊ณผ ์ด๋ฅผ ๊ธฐ๋ฐ˜์œผ๋กœ ํ•œ ์ˆ˜ํ•™์  ๋ชจ๋ธ๋ง์— ๋Œ€ํ•œ ์—ฐ๊ตฌ๋“ค์ด ๋งŽ์ด ์ง„ํ–‰๋˜์–ด์™”๋‹ค. ํ•˜์ง€๋งŒ, ๊ธฐ์กด์˜ ์ˆ˜ํ•™์  ๋ชจ๋ธ์ด ์•„์ง๊นŒ์ง€ ์‹ฌํ์†Œ์ƒ์ˆ  ์ค‘์˜ ํ˜ˆ์—ญํ•™์  ํ˜„์ƒ์„ ์ œ๋Œ€๋กœ ๋ฐ˜์˜ํ•˜์ง€ ๋ชปํ•˜๊ณ  ์žˆ๋Š” ๋ถ€๋ถ„์ด ์žˆ๋‹ค. ๋˜ํ•œ, ์ตœ๊ทผ ์‹ฌํ์†Œ์ƒ์ˆ  ์—ฐ๊ตฌ์˜ ๋ฐฉํ–ฅ์„ฑ์€ ํ™˜์ž ๋งž์ถคํ˜•์œผ๋กœ ๋‚˜์•„๊ฐ€๊ณ  ์žˆ๋‹ค. ํ•˜์ง€๋งŒ, ํ™˜์ž ๋งž์ถคํ˜• ์‹ฌํ์†Œ์ƒ์ˆ ์€ ํ™˜์ž ๊ฐœ์ธ์˜ ์š”์†Œ ๋ฐ ์ฃผ๋ณ€ ํ™˜๊ฒฝ ์š”์†Œ๋“ค์˜ ์˜ํ–ฅ์„ ๋ฐ›๊ธฐ ๋•Œ๋ฌธ์— ์ž„์ƒํ™˜๊ฒฝ์—์„œ ์ ‘๊ทผํ•˜๋Š” ๊ฒƒ์ด ์‰ฝ์ง€ ์•Š๋‹ค. ๋”ฐ๋ผ์„œ, ๋ณธ ์—ฐ๊ตฌ๋Š” ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ธฐ๋ฐ˜์˜ ์ด๋ก ์  ์—ฐ๊ตฌ๋ฅผ ํ†ตํ•ด ์‹ฌํ์†Œ์ƒ์ˆ  ์ค‘์˜ ํ˜ˆ์—ญํ•™์— ๋Œ€ํ•œ ์ดํ•ด์™€ ํ†ต์ฐฐ๋ ฅ์„ ์ œ๊ณตํ•˜๊ณ ์ž 3๊ฐ€์ง€ ๋ชฉํ‘œ๋ฅผ ๊ธฐ๋ฐ˜์œผ๋กœ ์—ฐ๊ตฌ๋ฅผ ์ˆ˜ํ–‰ํ•˜์˜€๋‹ค. ์ฒซ๋ฒˆ์งธ๋Š” ํ˜„์žฌ ์‹ฌํ์†Œ์ƒ์ˆ ์˜ ํ˜ˆ์—ญํ•™์  ํ˜„์ƒ์„ ๋ฐ˜์˜ํ•  ์ˆ˜ ์žˆ๋Š” ๊ฐœ์„ ๋œ ์ผ๋ฐ˜ํ™”๋œ ์‹ฌํ์†Œ์ƒ๋ชจ๋ธ์„ ๊ฐœ๋ฐœํ•˜๋Š” ๊ฒƒ์„ ๋ชฉํ‘œ๋กœ ํ•˜์˜€๋‹ค. ๋ณธ ์—ฐ๊ตฌ์—์„œ ์ œ์•ˆํ•˜๋Š” ๊ฐœ์„ ๋œ ์‹ฌํ์†Œ์ƒ๋ชจ๋ธ์€ ๊ธฐ์กด ๋ชจ๋ธ์— ์ƒ๋Œ€์ •๋งฅ๊ณผ ํ•˜๋Œ€์ •๋งฅ ๊ตฌํš์„ ์ถ”๊ฐ€ํ•˜์˜€๊ณ , โ€œํ•˜์ด๋ธŒ๋ฆฌ๋“œ ํŽŒํ”„โ€ ๋ฉ”์ปค๋‹ˆ์ฆ˜์„ ์ ์šฉํ•˜์˜€๋‹ค. ๊ธฐ์กด ๋ชจ๋ธ๊ณผ ๊ฐœ์„ ๋œ ๋ชจ๋ธ์˜ ํ˜ˆ์—ญํ•™์ ์ธ ํ˜„์ƒ์„ ๋น„๊ตํ•˜๊ธฐ ์œ„ํ•ด ๋‹ค์–‘ํ•œ ๊ธฐ๋ฒ•์— ๋Œ€ํ•œ ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๋ฐ ๋™๋ฌผ ๋ชจ๋ธ๋กœ๋ถ€ํ„ฐ ์–ป์€ ๋ฐ์ดํ„ฐ๋ฅผ ๋น„๊ตํ•˜์˜€๋‹ค. ๋™๋ฌผ ๋ชจ๋ธ๊ณผ ๊ธฐ์กด ๋ชจ๋ธ, ๊ฐœ์„ ํ•œ ๋ชจ๋ธ์˜ ์••๋ ฅ ๊ณก์„  ๋ฐ ๊ด€์ƒ๋™๋งฅ๊ด€๋ฅ˜์•• ๋“ฑ์„ ๋น„๊ตํ•œ ๊ฒฐ๊ณผ, ๋ณธ ์—ฐ๊ตฌ์—์„œ ๊ฐœ์„ ํ•œ ๋ชจ๋ธ์ด ํ˜„์žฌ์˜ ์‹ฌํ์†Œ์ƒ์ˆ  ๋ฉ”์ปค๋‹ˆ์ฆ˜์„ ๋” ์ž˜ ๋ฐ˜์˜ํ•˜๋Š” ์‹ฌํ์†Œ์ƒ๋ชจ๋ธ์ž„์„ ๊ฒ€์ฆํ•˜์˜€๋‹ค. ๋‘ ๋ฒˆ์งธ ๋ชฉํ‘œ๋Š” ๊ฐœ์„ ํ•œ ๋ชจ๋ธ์„ ๊ธฐ๋ฐ˜์œผ๋กœ ํ˜„์žฌ์˜ ์‹ฌํ์†Œ์ƒ์ˆ  ๋ฐฉ๋ฒ•์œผ๋กœ๋ถ€ํ„ฐ ๋ฐœ์ƒํ•˜๋Š” ์ด์Šˆ์ธ ํ‰๊ฐ•์˜ ํƒ„์„ฑ๋ ฅ ๊ฐ์†Œ์— ์˜ํ•œ ๋ถ€์ •์ ์ธ ์˜ํ–ฅ๊ณผ ์ตœ์ ์˜ ์••๋ฐ• ์œ„์น˜์— ๋Œ€ํ•ด ์‹œ๋ฎฌ๋ ˆ์ด์…˜์„ ํ†ตํ•ด ํ˜ˆ์—ญํ•™์ ์ธ ํ•ด์„์„ ์ œ๊ณตํ•˜๊ณ ์ž ํ•˜์˜€๋‹ค. ๊ฒฐ๊ณผ์—์„œ ํ‰๊ฐ•์˜ ํƒ„์„ฑ๋ ฅ์ด ๊ฐ์†Œํ•จ์— ๋”ฐ๋ผ ์••๋ฐ• ์ค‘ ์ตœ๋Œ€ ์••๋ ฅ์ด ๊ฐ์†Œํ•˜๋ฉฐ, ์ •๋งฅ ๋ณต๊ท€ ๋ฐ ํ˜ˆ๋ฅ˜ ์—ญ์‹œ ๊ฐ์†Œํ•˜๋Š” ๊ฒฐ๊ณผ๋ฅผ ๋ณด์˜€๋‹ค. ์••๋ฐ• ์œ„์น˜ ๋ณ€ํ™”๋Š” ์‹ฌ์‹ค๊ณผ ์‹ฌ๋ฐฉ์˜ ์••๋ฐ• ๋น„์œจ์„ ์กฐ์ ˆํ•˜์—ฌ ์‹œ๋ฎฌ๋ ˆ์ด์…˜์„ ์ˆ˜ํ–‰ํ•˜์˜€๋‹ค. ์ด ๊ฒฐ๊ณผ์—์„œ ์‹ฌ์‹ค๋ณด๋‹ค ์‹ฌ๋ฐฉ์ด ๋” ๋งŽ์ด ์••๋ฐ•๋  ๊ฒฝ์šฐ 1ํšŒ ๋ฐ•์ถœ๋Ÿ‰ ๋ฐ ๊ด€์ƒ๋™๋งฅ ๊ด€๋ฅ˜ ์••์ด ๊ฐ์†Œํ•˜๋ฉด์„œ ํ˜ˆ์—ญํ•™์ด ์ œํ•œ๋˜๋Š” ๊ฒฐ๊ณผ๋ฅผ ๋ณด์—ฌ์ฃผ์—ˆ๋‹ค. ๋”ฐ๋ผ์„œ, ์••๋ฐ• ์ค‘ ์ตœ๋Œ€ ์••๋ ฅ ๋ณ€ํ™”์™€ ๊ด€์ƒ๋™๋งฅ๊ด€๋ฅ˜์••์˜ ๋ณ€ํ™”๋Š” ํ‰๊ฐ•์˜ ํƒ„์„ฑ๋ ฅ ๋ณ€ํ™” ์ถ”์ • ๋ฐ ์••๋ฐ• ์œ„์น˜ ๊ฐ€์ด๋“œ๋ฅผ ํ•ด์ค„ ์ˆ˜ ์žˆ๋Š” ์ž ์žฌ๋ ฅ์„ ๊ฐ€์งˆ ์ˆ˜ ์žˆ์Œ์„ ์ž…์ฆํ•˜์˜€๋‹ค. ๋งˆ์ง€๋ง‰์œผ๋กœ ํ™˜์ž ๋งž์ถคํ˜• ์‹ฌํ์†Œ์ƒ์ˆ ๋ชจ๋ธ์˜ ๊ฐ€๋Šฅ์„ฑ์„ ์ œ์‹œํ•˜๊ณ ์ž ํ•˜์˜€๋‹ค. ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ์œ ์ „์ž ์•Œ๊ณ ๋ฆฌ์ฆ˜์„ ํ†ตํ•ด ํ™˜์ž ๊ฐœ๋ณ„์— ๋Œ€ํ•œ ์‹ฌํ˜ˆ๊ด€๊ณ„ ํŒŒ๋ผ๋ฏธํ„ฐ๋ฅผ ์ถ”์ •ํ•˜์˜€๊ณ , ํ™˜์ž๋งˆ๋‹ค ๋‹ค๋ฅธ ์‹ฌํ˜ˆ๊ด€๊ณ„ ํŒŒ๋ผ๋ฏธํ„ฐ ์„ธํŠธ๋ฅผ ๊ฐ€์ง์œผ๋กœ์จ ๋งž์ถคํ˜• ์‹ฌํ˜ˆ๊ด€๊ณ„ ๋ชจ๋ธ์„ ๊ตฌ์„ฑํ•  ์ˆ˜ ์žˆ์Œ์„ ๊ฒ€์ฆํ•˜์˜€๋‹ค. ๋˜ํ•œ, ๋งž์ถคํ˜• ์‹ฌํ˜ˆ๊ด€๊ณ„ ๋ชจ๋ธ์— ์‹ฌํ์†Œ์ƒ๋ชจ๋ธ์„ ์ ์šฉํ•˜์—ฌ ์‹ฌํ˜ˆ๊ด€๊ณ„ ํŒŒ๋ผ๋ฏธํ„ฐ ๊ตฌ์„ฑ์— ๋”ฐ๋ผ ํ‰๋ถ€ ์••๋ฐ• ์‹œ ํ˜ˆ์—ญํ•™์  ์˜ํ–ฅ์ด ๋‹ฌ๋ผ์ง์„ ๊ฒ€์ฆํ•˜์˜€๋‹ค. ์ถ”๊ฐ€์ ์œผ๋กœ ๋ผ์ง€ ๋ชจ๋ธ์—์„œ ๋‹ค์–‘ํ•œ ์••๋ฐ• ์กฐ๊ฑด ๋ณ€ํ™”์— ๋Œ€ํ•œ ํ˜ˆ์—ญํ•™์  ๋ณ€ํ™”๋ฅผ ๋น„๊ตํ•˜์˜€๊ณ , ์ด๋ฅผ ํ†ตํ•ด ๋งž์ถคํ˜• ๋ชจ๋ธ์„ ํ†ตํ•ด ์ตœ์ ์˜ ํ˜ˆ์—ญํ•™์  ํšจ๊ณผ๋ฅผ ๊ฐ–๋Š” ์••๋ฐ• ์กฐ๊ฑด์„ ์ œ์‹œํ•  ์ˆ˜ ์žˆ์Œ์„ ๋ณด์˜€๋‹ค. ๊ฒฐ๋ก ์ ์œผ๋กœ ๋ณธ ์—ฐ๊ตฌ๋ฅผ ํ†ตํ•ด ์ œ์•ˆํ•˜๋Š” ์‹ฌํ์†Œ์ƒ ๋ชจ๋ธ์ด ํ˜„์žฌ ์‹ฌํ์†Œ์ƒ์ˆ ์— ์˜ํ•œ ๋ฉ”์ปค๋‹ˆ์ฆ˜์„ ๋” ์ž˜ ๋ฐ˜์˜ํ•˜๋Š” ์ผ๋ฐ˜ํ™”๋œ ๋ชจ๋ธ์ž„์„ ๋ณด์—ฌ์ฃผ์—ˆ๊ณ , ์ด๋ฅผ ํ†ตํ•ด ํ˜„์žฌ ์‹ฌํ์†Œ์ƒ์ˆ  ๋ฐฉ๋ฒ•์— ์˜ํ•œ ์ด์Šˆ์— ๋Œ€ํ•ด์„œ ํ˜ˆ์—ญํ•™์ ์ธ ํ•ด์„์ด ๊ฐ€๋Šฅํ•จ์„ ์ž…์ฆํ•˜์˜€๋‹ค. ๋˜ํ•œ, ์ด๋ฅผ ๊ธฐ๋ฐ˜์œผ๋กœ ํ™˜์ž ๋งž์ถคํ˜• ์‹ฌํ์†Œ์ƒ ๋ชจ๋ธ์˜ ๊ฐ€๋Šฅ์„ฑ ์ œ์‹œํ•จ์œผ๋กœ์จ ๋งž์ถคํ˜• ์‹ฌํ์†Œ์ƒ ๋ชจ๋ธ๋ง์— ๋Œ€ํ•œ ์—ฐ๊ตฌ์˜ ๊ธฐ๋ฐ˜์ด ๋  ์ˆ˜ ์žˆ์Œ์„ ๋ณด์—ฌ์ฃผ์—ˆ๋‹ค.For a long time, many studies based on mathematical modeling have been conducted to understand cardiopulmonary resuscitation (CPR) physiology. However, some aspects of the existing CPR model do not reflect the current CPR physiology appropriately. If the generalized CPR model does not suitably reflect the hemodynamic phenomena of current CPR, errors may exist in the hemodynamic interpretation. In addition, it is suggested that the one-size-fits-all CPR specified in the guidelines is not suitable, and the direction of recent CPR research is shifting toward personalized CPR. However, in personalized CPR, it is difficult to use preclinical or clinical trial approaches because various factors associated with the patient and environment interact and affect the patient. Therefore, this study was conducted with three goals to provide insight into the hemodynamics during CPR through a simulation-based approach. The first objective was to develop an improved generalized CPR model that can reflect the current CPR physiology. The modified CPR model proposed herein added superior and inferior vena cava compartments in the thoracic cavity of the existing model, as well as a โ€œhybrid pumpโ€ mechanism. To compare the hemodynamic effects of the existing and modified models, various maneuvers such as the active compression-decompression CPR combined with the impedance threshold device, head-up tilt, and head-down tilt were simulated. Additionally, the modified model was compared with an animal model to confirm that it reflects the current CPR physiology more than the existing model does. The comparison showed that the pressure waveform and coronary perfusion pressure (CPP) were more appropriately reflected than in the existing model. Therefore, it was verified that the improved model developed in this study is a generalized CPR model that reflects the current CPR physiology more accurately. The second goal was to verify the hemodynamic effects on the reduced thoracic elasticity and compression positionโ€”which are the current issues of the existing CPR techniqueโ€”through simulation based on the improved model. The reduced elasticity of the thorax was simulated to decrease linearly for 1 min immediately after the start of CPR. The results show that as the elasticity of the thorax decreased, the pressure amplitude of the aorta and vena cava decreased during compression, along with the venous return and blood flow. Furthermore, a simple simulation was performed by adjusting the compression ratio between the ventricle and atrium with the thoracic pump factor to compare the hemodynamic difference according to the compression position. Consequently, when the atrium was compressed more than the ventricle, the stroke volume and CPP decreased, indicating that hemodynamics was limited. Therefore, it was demonstrated that a change in the pressure amplitude and CPP during compression could potentially enable estimation of the change in the elasticity of the thorax and assist in determining the position of compression. Finally, this study attempted to present the possibility of a personalized CPR model. Cardiovascular parameters were estimated for different patients using a genetic algorithm. Additionally, it was confirmed that patient-specific cardiovascular models could be constructed with different sets of parameters for each patient. Furthermore, incorporating the CPR model into the patient-specific cardiovascular model revealed that the hemodynamic effect of chest compression varies according to the cardiovascular parameter configuration. The hemodynamic changes for different compression conditions were compared in a pig model. From the results, it was shown that various hemodynamics occurred depending on the compression condition when using the personalized CPR model. Thus, it is possible to determine the optimal compression condition for the patient-specific from this. In conclusion, this study showed that the modified CPR model is a generalized model that reflects the current CPR physiology more accurately. It also proved that hemodynamic interpretation can address the limitations of the current CPR technique through the modified model. Additionally, by presenting the possibility of a patient-specific CPR model based on this, this study can serve as the basis for research on personalized CPR modeling.Chapter 1. Introduction 1 1.1 Basic understanding of cardiovascular system 2 1.1.1 Cardiac output 2 1.1.2 Venous return and Frank-Starling law 5 1.1.3 Blood circulatory system 7 1.2 Cardiopulmonary resuscitation (CPR) 10 1.2.1 Basic concept for CPR 10 1.2.2 Theories for CPR mechanism 13 1.3 Mathematical modeling for CPR 15 1.3.1 Basic concept of lumped parameter model for cardiovascular system 15 1.3.2 Previous studies on CPR modeling 20 1.4 Motivation and objectives 22 Chapter 2. Materials and Methods 29 2.1 Modified CPR model for general CPR model 30 2.1.1 Modified hybrid CPR model 30 2.1.2 Simulations of various maneuvers for CPR model 35 2.1.2.1 Active compression-decompression CPR with an impedance threshold valve (ACD-CPR+ITV) 35 2.1.2.2 Head-up tilt (HUT) and head-down tilt (HDT) 37 2.1.3 Animal experiments for hemodynamic data acquisition 39 2.1.3.1 Experimental protocol 40 2.1.3.2 Data acquisition 41 2.2 Simulation-based approach to current issues in CPR using modified hybrid CPR model 42 2.2.1 Reduced elasticity of thorax 42 2.2.1 Ventricle-atrium compression ratio (VAR) for compression position 43 2.3 Parameter estimation of simple cardiovascular model for patient-specific CPR model 45 2.3.1 Simple cardiovascular model 45 2.3.2 Genetic algorithm for parameter estimation 47 2.3.3 Application of CPR model to patient-specific cardiovascular model 49 Chapter 3. Results and Discussion 51 3.1 Modified CPR model based on general CPR model 52 3.1.1 Comparison results of animal experiments and simulations 54 3.1.2 Hemodynamic effects on the various maneuvers 58 3.1.2.1 Comparison of CPR techniques 58 3.1.2.2 HUT and HDT 60 3.2 Simulation-based approach to current issues in CPR using modified CPR model 64 3.2.1 Hemodynamic effects on reduced elasticity of thorax 64 3.2.2 Coronary perfusion pressure for various VAR 68 3.3 Parameter estimation of simple cardiovascular model for patient-specific CPR model 72 3.3.1 Verification of parameter estimation using open dataset 74 3.3.2 Application to patient-specific CPR model 88 3.4 Limitations 100 Chapter 4. Conclusion 102 4.1 Dissertation summary 103 4.2 Future works 105 References 107 Abstract in Korean 117 Acknowledgement 119 ๊ฐ์‚ฌ์˜ ๊ธ€ 120๋ฐ•

    The Risk Factors Associated With Delirium After Lumbar Spine Surgery in Elderly Patients

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    Background: To prospectively explore the incidence and risk factors for postoperative delirium in elderly patients following lumbar spine surgery. Methods: This prospective study enrolled 148 consecutive patients over the age of 65 who were scheduled to undergo spine surgery. Patients were screened for delirium using the short Confusion Assessment Method (CAM) postoperatively. Patient demographics and relevant medical information were collected. Logistic regression analysis was used to identify the risk factors associated with postoperative delirium. Results: Eighty-three patients (56.1%) who underwent lumbar spine surgery (not coexisting with cervical or thoracic spine surgery) were enrolled in our study. Post-operative delirium was noted in 14.5% of patients over 65 years old. The presence of preoperative Parkinsonism was significantly higher in the delirium group (41.7% vs. 8.5%, P=0.002), as was a higher preoperative C-reactive protein (CRP) (7.0ยฑ15.2 vs. 1.3ยฑ2.3 mg/L, P=0.017) when compared with the non-delirium group. Of the risk factors, male sex [odds ratio (OR) =0.10, 95% confidence interval (CI): 0.01-0.66, P=0.017], Parkinsonism (OR =5.83, 95% CI: 1.03-32.89, P=0.046), and lower baseline MMSE score (OR =0.71, 95% CI: 0.52-0.97, P=0.032) were independently associated with postoperative delirium in elderly patients undergoing lumbar spine surgery. Conclusions: Post-operative delirium occurred in 14.5% of elderly patients who underwent lumbar spine surgery. Male sex, Parkinsonism, and lower baseline MMSE score were identified as independent risk factors for postoperative delirium in elderly patients following lumbar surgery.ope

    Influence of Diabetes Mellitus on Patients With Lumbar Spinal Stenosis: A Nationwide Population-Based Study

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    Purpose: To evaluate the relationship between comorbidities, medical cost, and surgical outcome in patients with lumbar spinal stenosis (LSS) and diabetes mellitus (DM). Methods: Data on patients with LSS (n = 14,298) were collected from the Korean National Health Insurance Service database from 2005 to 2007. After 8 years of follow-up, a "DM group" (n = 3,478) and a "non-DM group" (n = 10,820) were compared according to outcome measures. Cox proportional hazard regressions were performed to examine the relationship between DM, hypertension (HTN), cardiovascular disease (CVD), chronic kidney disease (CKD), cerebrovascular disease (CbVD), and surgery for LSS. The admission rate and medical cost as well asthe overall survival rate for those who underwent lumbar surgery were also assessed among patients with DM and LSS. Results: Mortality was about 1.35 times higher in the DM group than in the non-DM group. Patients with DM and comorbidities including HTN (hazard ratio [HR], 1.40; 95% confidence interval [CI], 1.25-1.56; p<0.001), CVD (HR, 1.53; 95% CI, 1.36-1.73; p<0.001), CKD (HR, 3.18; 95% CI, 2.7-3.76; p<0.001), and CbVD (HR, 1.69; 95% CI, 1.49-1.91; p<0.001) showed an increased risk of mortality. The mean hospitalization time and average medical cost of patients with DM who underwent lumbar surgery were 60.8 days, and 7,127 USD, respectively. This was 31.3 days longer, and 6,207 USD higher, respectively, than those of patients with DM who underwent conservative treatment for LSS. Within the DM group, the survival rate of surgical management of LSS had a significant tendency for positive prognosis compared with those administered conservative treatment (p = 0.046). Conclusions: In patients with LSS, DM was associated both with poor prognosis (most significantly in those with CKD), and increased medical cost in those who underwent surgery. Nevertheless, surgical treatment for LSS in patients with DM was related to favorable prognosis compared with conservative treatment.ope

    Biomechanical Analysis of Biodegradable Cervical Plates Developed for Anterior Cervical Discectomy and Fusion

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    STUDY DESIGN: In-vitro biomechanical investigation. PURPOSE: To evaluate the biomechanical effects of the degeneration of the biodegradable cervical plates developed for anterior cervical discectomy and fusion (ACDF) on fusion and adjacent levels. OVERVIEW OF LITERATURE: Biodegradable implants have been recently introduced for cervical spine surgery. However, their effectiveness and safety remains unclear. METHODS: A linear three-dimensional finite element (FE) model of the lower cervical spine, comprising the C4-C6 vertebrae was developed using computed tomography images of a 46-year-old woman. The model was validated by comparison with previous reports. Four models of ACDF were analyzed and compared: (1) a titanium plate and bone block (Tita), (2) strong biodegradable plate and bone block (PLA-4G) that represents the early state of the biodegradable plate with full strength, (3) weak biodegradable plate and bone block (PLA-1G) that represents the late state of the biodegradable plate with decreased strength, and (4) stand-alone bone block (Bloc). FE analysis was performed to investigate the relative motion and intervertebral disc stress at the surgical (C5-C6 segment) and adjacent (C4-C5 segment) levels. RESULTS: The Tita and PLA-4G models were superior to the other models in terms of higher segment stiffness, smaller relative motion, and lower bone stress at the surgical level. However, the maximal von Mises stress at the intervertebral disc at the adjacent level was significantly higher in the Tita and PLA-4G models than in the other models. The relative motion at the adjacent level was significantly lower in the PLA-1G and Bloc models than in the other models. CONCLUSIONS: The use of biodegradable plates will enhance spinal fusion in the initial stronger period and prevent adjacent segment degeneration in the later, weaker period.ope

    Biomechanical Comparison of Spinal Fusion Methods Using Interspinous Process Compressor and Pedicle Screw Fixation System Based on Finite Element Method

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    OBJECTIVE: To investigate the biomechanical effects of a newly proposed Interspinous Process Compressor (IPC) and compare with pedicle screw fixation at surgical and adjacent levels of lumbar spine. METHODS: A three dimensional finite element model of intact lumbar spine was constructed and two spinal fusion models using pedicle screw fixation system and a new type of interspinous devices, IPC, were developed. The biomechanical effects such as range of motion (ROM) and facet contact force were analyzed at surgical level (L3/4) and adjacent levels (L2/3, L4/5). In addition, the stress in adjacent intervertebral discs (D2, D4) was investigated. RESULTS: The entire results show biomechanical parameters such as ROM, facet contact force, and stress in adjacent intervertebral discs were similar between PLIF and IPC models in all motions based on the assumption that the implants were perfectly fused with the spine. CONCLUSION: The newly proposed fusion device, IPC, had similar fusion effect at surgical level, and biomechanical effects at adjacent levels were also similar with those of pedicle screw fixation system. However, for clinical applications, real fusion effect between spinous process and hooks, duration of fusion, and influence on spinous process need to be investigated through clinical study.ope

    Intradural extramedullary ependymoma with spinal root attachment: a case report

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    A 36-year-old female patient presented with shoulder pain experienced over a period of one year and progressive weakness in both legs for one month. A magnetic resonance imaging scan revealed an intradural extramedullary (IDEM) fusiform mass about 9.8 cm in length, heterogeneously enhanced at the level of C6-T4 with spinal cord compression. At the time of surgery, the surgeon found an encapsulated IDEM tumor with spinal root attachment. The tumor was completely resected and the histologic diagnosis revealed ependymoma. The patient showed a favorable outcome with no recurrence at the 6-month follow-up. This paper reports a rare case of intradural extramedullary ependymoma with spinal root attachment.ope

    Association between VEGF and eNOS gene polymorphisms and lumbar disc degeneration in a young Korean population

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    Disturbances in blood flow to intervertebral discs (IVD) play an important role in IVD degeneration. Vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS) are extremely important angiogenic factors for vasodilation and neovascularization. We investigated the relationship between single nucleotide polymorphisms (SNPs) of the VEGF and eNOS genes and genetic susceptibility to lumbar IVD degeneration in a young adult Korean population. Two hundred and forty-one participants (aged 18 to 30 years), with or without low back pain, were selected for the study. Magnetic resonance imaging was made of the lumbar spine in all participants. The patient group (N = 102) had low back pain clinically and lumbar IVD degeneration radiographically. The control group (N = 139) included subjects with and without low back pain; all were negative radiographically for lumbar IVD degeneration. Using PCR-RFLP analysis, we analyzed VEGF (-2578C>A, -1154G>A, -634G>C, and 936C>T) and eNOS (-786T>C, 4a4b and 894G>T) SNPs. We made combined analyses of the genes and performed haplotype analyses. There were no significant differences in the genotype distribution of polymorphisms of VEGF and eNOS genes among patients and controls. However, the frequency of VEGF -2578CA +AA/-634CC combined genotypes was significantly higher in patients when compared with controls [odds ratio (OR) = 21.00; 95% confidence interval (CI) = 2.590- 170.240]. The frequencies of the -2578A/-1154A/-634C/936C (OR = 3.831; 95%CI = 1.068-13.742), -2578A/-1154A/-634C (OR = 3.356; 95%CI = 1.198-9.400), and -2578A/-634C/936C (OR = 10.820; 95%CI = 2.811-41.656) haplotypes were also significantly higher in patients than in controls. We conclude that the combined genotype VEGF -2578CA+AA/-634CC is a possible risk factor for IVD degeneration and the VEGF -2578A/-1154A/-634C/936C haplotype may increase the risk for development of IVD degeneration. Furthermore, the VEGF -634C allele appears to be associated with susceptibility to IVD degeneration.ope

    ASIA SPINE: The Past, Present, and Future

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    The sharing of international academic accomplishment and friendship is important; furthermore, to better understand and anticipate the future, we should look back and remember where we started. Regarding ASIA SPINE, the authors aimed to record how the pioneers of Asian spinal surgery started this spine meeting series more than 20 years ago and that later developed into the present state of the conference. The authors will also explore the possible future of this conference. In June 1996, when Professor Hiroshi Nakagawa organized the 11th Annual Meeting of the Japanese Society of Spinal Surgery, spinal neurosurgeons from Korea and Japan including Professor Young Soo Kim, Professor Jung Keun Suh, and Professor Nakagawa discussed the establishment of a multinational conference on spinal surgery via a partnership between the 2 countries. Finally, from September 18 to 20, 1997, the First Biennial Meeting of the Japan-Korea Conference on Spinal Surgery was held in Nagoya, Japan, with Professor Hiroshi Nakagawa as the first organizing President. From then, a biennial meeting was held every other year in Korea or Japan until 2009. In September 2010, the next generation of spinal neurosurgeons decided to organize the first meeting of ASIA SPINE in Incheon, Korea, in order to represent all Asian spine specialists. This meeting has been since held annually around the region including in Taiwan. Remembering the pioneers in the field of spinal surgery is invaluable and extremely important. The authors hope that interest in ASIA SPINE will further expand to other nations in Asia who have advanced philosophies and refined technologies. We wish ASIA SPINE continued success and the ability to promote prolonged international friendship among the Asian countries .ope
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