• Journal of Korean Neurosurgical Society
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• 제66권6호
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• pp.703-715
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• 2023

Objective : This retrospective study investigated the factors that affect cage obliquity angle despite orthogonal maneuvers performed during oblique lateral interbody fusion (OLIF) and assessed the relationship between cage obliquity angle and radiological outcomes post-surgery. Methods : Twenty-nine males who underwent L4-L5 OLIF for lumbar degenerative disease between 2019 and 2021 with a followup duration greater than 12 months were analyzed. Radiological parameters were measured including psoas muscle volume, total psoas area index (total psoas muscle area [cm²]/height squared [m²]), distance from the iliac artery to the origin of the psoas muscle (DIAPM), angle between the origin of the psoas muscle and the center of the vertebral disc (APCVD), iliac crest height, disc height, lumbar flexibility (lumbar flexion angle minus extension angle), cage location ratio, cage-induced segmental lumbar lordosis (LL) (postoperative index level segmental LL minus used cage angle), foraminal height changes, fusion grade. Results : DIAPM, APCVD, iliac crest height, postoperative index level segmental LL, and cage-induced segmental LL were significantly correlated with OLIF cage obliquity angle. However, other radiological parameters did not correlate with cage obliquity. Based on multiple regression analysis, the predictive equation for the OLIF cage obliquity angle was 13.062-0.318×DIAPM+0.325×1APCVD+0.174×iliac crest height. The greater the cage obliquity, the smaller the segmental LL compared to the cage angle used. Conclusion : At the L4-L5 level, OLIF cage obliquity was affected by DIAPM, APCVD, and iliac crest height, and as the cage obliquity angle increases, LL agnle achievable by the used cage could not be obtained.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.517-518
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• 2006

In this study, a commercial fixation device, BioFlex, which was designed with shape memory alloy(SMA) for dynamic stabilization of spine was biomechanically evaluated. The finite element model of intact lumbar spine from L1 to S was developed using CT images. Also, low FE models of 2-level(L4-L5-S) and 3-level(L3-L4-L5-S) posteriori fixation using titanium(Ti) rod and BioFlex(SMA) rod. The rotations of bone segments in the intact model and four models were predicted. Although the rotations of the BioFlex fixation model were smaller than those of the intact model, they were relatively larger than those of Ti fixation. The present can be applied for not only evaluation of the stability of interbody fixator, but also development of new implant.

• Journal of Korean Neurosurgical Society
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• 제60권6호
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• pp.691-700
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• 2017

Objective : The authors prospectively analyzed the effect of one-level or two-level anterior cervical discectomy and fusion (ACDF), comparing stand-alone cages and cage-with-plate fixation constructs with respect to clinical outcomes and radiologic changes. Methods : A total of 84 patients who underwent one-level (n=52) or two-level ACDF (n=32) for cervical disc disease and who completed 2 years of follow-up were included in this study. The patients were divided by cervical level and grouped into ACDF-Cage-only and ACDF-Cage-with-plate groups. The following parameters were assessed using radiographs : subsidence, C2-C7 lordosis angle, fusion segment angle, adjacent disc space narrowing, and fusion status. Clinical outcomes were assessed using the neck disability index (NDI) and visual analog scale scores for arm pain. Results : In the comparison of one-level ACDF-cage-only and ACDF-cage-with-plate groups, the NDI score was better in the cage-only group at the 3-, 12-, and 24-month follow-ups : however, no significant difference in clinical outcomes was observed. In the comparison of two-level ACDF-cage-only and ACDF-cage-with-plate groups, no difference in any clinical outcome was observed between the two groups. At the 24-month follow-up, subsidence was observed in 45.8% of patients in the one-level cage-only group and 32.1% of patients in the one-level cage-with-plate fixation group. There was no statistically significant difference in the incidence rate between the two groups (p=0.312). Subsidence in the two-level cage-only group (66.6%) was significantly more frequent than in the two-level cage-with-plate fixation group (30%; p=0.049). The fusion rate for patients in the one-level cage-only group was not significantly different from that in the one-level cage-with-plate fixation group (cage-only, 87.5%; cage-with-plate fixation, 92.9%; p=0.425) ; fusion rate in the two-level patients were also similar between groups (cage-only, 83.3%; cage-with-plate fixation, 95%; p=0.31). Conclusion : Our clinical results showed that for single-level cases, plate fixation had no additional benefit versus cage-only; for two-level ACDF cases, the fusion rate and clinical outcomes were similar, although the cage-with-plate fixation group had a lower incidence of cage subsidence than did the cage-only group. We conclude that physicians should be aware of this possible disadvantage associated with using cervical plates in one-level ACDF. However, in two-level ACDF, subsidence is more likely to occur without plate fixation, and thus the addition of plate fixation should be considered.

• Journal of Korean Neurosurgical Society
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• 제62권4호
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• pp.422-431
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• 2019

Objective : In an aging society, the number of patients with symptomatic degenerative spondylolisthesis (DS) is increasing and there is an emerging need for fusion surgery. However, few studies have compared transforaminal lumbar interbody fusion (TLIF) and lateral lumbar interbody fusion (LLIF) for the treatment of patients with DS. The purpose of this study was to investigate the clinical and radiological outcomes between TLIF and LLIF in DS. Methods : We enrolled patients with symptomatic DS at L4-5 who underwent TLIF with open pedicle screw fixation (TLIF group, n=41) or minimally invasive LLIF with percutaneous pedicle screw fixation (LLIF group, n=39) and were followed-up for more than one year. Clinical (visual analog scale and Oswestry disability index) and radiological outcomes (spondylolisthesis rate, segmental sagittal angle [SSA], mean disc height [MDH], intervertebral foramen height [FH], cage subsidence, and fusion rate) were assessed. And we assessed the changes in radiological parameters between the postoperative and the last follow-up periods. Results : Preoperative radiological parameters were not significantly different between the two groups. LLIF was significantly superior to TLIF in immediate postoperative radiological results, including reduction of spondylolisthesis rate (3.8% and 7.2%), increase in MDH (13.9 mm and 10.3 mm) and FH (21.9 mm and 19.4 mm), and correction of SSA ($18.9^{\circ}$ and $15.6^{\circ}$) (p<0.01), and the changes were more stable from the postoperative period to the last follow-up (p<0.01). Cage subsidence was observed significantly less in LLIF (n=6) than TLIF (n=21). Fusion rate was not different between the two groups. The clinical outcomes did not differ significantly at any time point between the two groups. Complications were not statistically significant. However, TLIF showed chronic mechanical problems with screw loosening in four patients and LLIF showed temporary symptoms associated with the surgical approach, such as psoas and ileus muscle symptoms in three and two cases, respectively. Conclusion : LLIF was more effective than TLIF for spondylolisthesis reduction, likely due to the higher profile cage and ligamentotactic effect. In addition, LLIF showed mechanical stability of the reduction level by using a cage with a larger footprint. Therefore, LLIF should be considered a surgical option before TLIF for patients with unstable DS.

• Journal of Korean Neurosurgical Society
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• 제40권2호
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• pp.90-94
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• 2006

Objective : Acute vertebral burst fractures warrant extensive fixation and fusion on the spine. Osteoplasty [vertebroplasty with high density resin without vertebral expansion] has been used to treat osteoporotic vertebral compression fractures. We report our experiences with osteoplasty in acute vertebral burst fractures. Methods : Twenty-eight cases of acute vertebral burst fracture were operated with osteoplasty. Eighteen patients had osteoporosis concurrently. Preoperative MRI was performed in all cases to find fracture level and to evaluate the severity of injury. Preoperative CT revealed burst fracture in the series. The patients with severe ligament injury or spinal canal compromise were excluded from indication. Osteoplasty was performed under local anesthesia and high density polymethylmethacrylate[PMMA] was injected carefully avoiding cement leakage into spinal canal. The procedure was performed unilaterally in 21 cases and bilaterally in 7 cases. The patients were allowed to ambulate right after surgery. Most patients discharged within 5 days and followed up at least 6 months. Results : There were 12 men and 16 women with average age of 45.3[28-82]. Five patients had 2 level fractures and 2 patients had 3 level fractures. The average injection volume was 5.6cc per level Average VAS [Visual Analogue Scale] improved 26mm after surgery. The immediate postoperative X-ray showed 2 cases of filler spillage into spinal canal and 4 cases of leakage into the retroperitoneal space. One patient with intraspinal leakage was underwent the laminectomy to remove the resin. Conclusion : Osteoplasty is a safe and new treatment option in the burst fractures. Osteoplasty with minimally invasive technique reduced the hospital stay and recovery time in vertebral fracture patients.

• Journal of Korean Neurosurgical Society
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• 제50권3호
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• pp.224-230
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• 2011

Objective : This study aimed to show the possibility of neural canal enlargement and restoration of bony fragments through laminectomy and minimal facetectomy without pediculectomy or an anterior approach, and also to prove the adequacy of posterior stabilization of vertebral deformities after thoracolumbar bursting fracture. Methods : From January 2003 to June 2009, we experienced 45 patients with thoracolumbar burst fractures. All patients enrolled were presented with either a neural canal compromise of more than 40% with a Benzel-Larson Grade of VI, or more than 30% compromise with less than a Benzel-Larson Grade of V. Most important characteristic of our surgical procedure was repositioning retropulsed bone fragments using custom-designed instruments via laminectomy and minimal facetectomy without removing the fractured bone fragments. Beneath the dural sac, these custom-designed instruments could push the retropulsed bone fragments within the neural canal after the decompression and bone fragment repositioning. Results : The mean kyphotic deformities measured preoperatively and at follow-up within 12 months were 17.7 degrees (${\pm}6.4$ degrees) and 9.6 degrees (${\pm}5.2$ degrees), respectively. The mean midsagittal diameter improved from 8.8 mm (${\pm}2.8$ mm) before surgery to 14.2 mm (${\pm}1.6$ mm) at follow-up. The mean traumatic vertebral body height before surgery was 41.3% (${\pm}12.6%$). At follow-up assessment within 12 months, this score showed a statistically significant increase to 68.3% (${\pm}12.8%$). Neurological improvement occurred in all patients. Conclusion : Though controversy exists in the treatment of severe thoracolumbar burst fracture, we achieved effective radiological and clinical results in the cases of burst fractures causing severe canal compromise and spinal deformity by using this novel custom-designed instruments, via posterior approach alone.

• Journal of Korean Neurosurgical Society
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• 제67권1호
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• pp.6-13
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• 2024

The integrity of the high cervical spine, the transition zone from the brainstem to the spinal cord, is crucial for survival and daily life. The region protects the enclosed neurovascular structure and allows a substantial portion of the head motion. Injuries of the high cervical spine are frequent, and the fractures of the C2 vertebra account for approximately 17-25% of acute cervical fractures. We review the two major types of C2 vertebral fractures, odontoid fracture and Hangman's fracture. For both types of fractures, favorable outcomes could be obtained if the delicately selected conservative treatment is performed. In odontoid fractures, as the most common fracture on the C2 vertebrae, anterior screw fixation is considered first for type II fractures, and C1-2 fusion is suggested when nonunion is a concern or occurs. Hangman's fractures are the second most common fracture. Many stable extension type I and II fractures can be treated with external immobilization, whereas the predominant flexion type IIA and III fractures require surgical stabilization. No result proves that either anterior or posterior surgery is superior, and the surgeon should decide on the surgical method after careful consideration according to each clinical situation. This review will briefly describe the basic principles and current treatment concepts of C2 fractures.

• Journal of Korean Neurosurgical Society
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• 제60권6호
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• pp.611-619
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• 2017

Objective : In addition to bone bridging inside a cage or graft (intragraft bone bridging, InGBB), extragraft bone bridging (ExGBB) is commonly observed after anterior cervical discectomy and fusion (ACDF) with a stand-alone cage. However, solid bony fusion without the formation of ExGBB might be a desirable condition. We hypothesized that an insufficient contact area for InGBB might be a causative factor for ExGBB. The objective was to determine the minimal area of InGBB by finite element analysis. Methods : A validated 3-dimensional, nonlinear ligamentous cervical segment (C3-7) finite element model was used. This study simulated a single-level ACDF at C5-6 with a cylindroid interbody graft. The variables were the properties of the incorporated interbody graft (cancellous bone [Young's modulus of 100 or 300 MPa] to cortical bone [10000 MPa]) and the contact area between the vertebra and interbody graft (Graft-area, from 10 to $200mm^2$). Interspinous motion between the flexion and extension models of less than 2 mm was considered solid fusion. Results : The minimal Graft-areas for solid fusion were $190mm^2$, $140mm^2$, and $100mm^2$ with graft properties of 100, 300, and 10000 MPa, respectively. The minimal Graft-areas were generally unobtainable with only the formation of InGBB after the use of a commercial stand-alone cage. Conclusion : ExGBB may be formed to compensate for insufficient InGBB. Although various factors may be involved, solid fusion with less formation of ExGBB may be achieved with refinements in biomaterials, such as the use of osteoinductive cage materials; changes in cage design, such as increasing the area of polyetheretherketone or the inside cage area for bone grafts; or surgical techniques, such as the use of plate/screw systems.

• 폴리머
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• 제34권5호
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• pp.398-404
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• 2010

본 연구팀은 DBP를 함침시킨 물성이 서로 다른 스폰지와 PLGA 지지체를 제작한 후 세포 부착, 증식 및 형태 유지를 알아보기 위한 실험을 수행하였다. WST 분석법과 SEM 관찰을 통하여 스폰지에 비해서 PLGA 지지체에서의 세포의 증식이 활발한 것을 확인하였고, RT-PCR을 통해 디스크세포에서 특이적으로 발현하는 제 2형 콜라겐과 어그리칸의 발현을 확인하였다. WST 결과, 세포 증식률은 DBP/PLGA 지지체가 DBP를 함침시킨 스폰지보다 세포 증식률이 높음을 확인하였다. 본 연구팀은 스폰지보다 PLGA 지지체가 인간디스크의 표현형 유지 및 증식에 있어서 긍정적인 영향을 미치는 것을 확인하였다.

• Journal of Korean Neurosurgical Society
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• 제40권1호
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• pp.22-27
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• 2006

Objective : The purpose of this study is to investigate the clinical results of anterior and posterior stabilization by one stage posterolateral approach for the unstable fracture of thoracolumbar and lumbar spine. Methods : By posterolateral approach with curved skin incision, unilateral facet and pedicle were removed. Through this route, corpectomy was performed, and then this space was replaced with mesh cage filled up with autologous bone graft. Both side pedicle screw fixation was followed to upper and lower levels. Results : Six of seven patients of this study showed neurological improvement. The other one patient showed no neurological change. One patient had postoperative infection, another patient had postoperative kyphosis. The other patient had epidural hematoma on operation site after surgery. And all patinets on this study made to have spinal stability except one patient happened postoperative kyphosis. Conclusion : In the unstable fracture of thoracolumbar and lumbar spine, one stage anterior and posterior stabilization and fusion by posterolateral approach seems to be an effective procedure, if we have more care and supplementation.