• Journal of Korean Neurosurgical Society
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• 제62권4호
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• pp.432-441
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• 2019

Objective : Few studies have reported direct comparative data of lumbar spine angles between direct lateral interbody fusion (DLIF) and oblique lateral interbody fusion (OLIF). The purpose of this study was to investigate the clinical and radiological outcomes of DLIF and OLIF, and determine influential factors. Methods : The same surgeon performed DLIF from May 2011 to August 2014 (n=201) and OLIF from September 2014 to September 2016 (n=142). Radiological parameters, cage height, cage angle (CA), cage width (CW), and cage location were assessed. We checked the cage location as the distance (mm) from the anterior margin of the disc space to the anterior metallic indicator of the cage in lateral images. Results : There were significant differences in intervertebral foramen height (FH; $22.0{\pm}2.4$ vs. $21.0{\pm}2.1mm$, p<0.001) and sagittal disc angle (SDA; $8.7{\pm}3.3$ vs. $11.3{\pm}3.2^{\circ}$, p<0.001) between the DLIF and OLIF groups at 7 days postoperatively. CA ($9.6{\pm}3.0$ vs. $8.1{\pm}2.9^{\circ}$, p<0.001) and CW ($21.2{\pm}1.6$ vs. $19.2{\pm}1.9mm$, p<0.001) were significantly larger in the OLIF group compared to the DLIF group. The cage location of the OLIF group was significantly more anterior than the DLIF group ($6.7{\pm}3.0$ vs. $9.1{\pm}3.6mm$, p<0.001). Cage subsidence at 1 year postoperatively was significantly worse in the DLIF group compared to the OLIF group ($1.0{\pm}1.5$ vs. $0.4{\pm}1.1mm$, p=0.001). Cage location was significantly correlated with postoperative FH (${\beta}=0.273$, p<0.001) and postoperative SDA (${\beta}=-0.358$, p<0.001). CA was significantly correlated with postoperative FH (${\beta}=-0.139$, p=0.044) and postoperative SDA (${\beta}=0.236$, p=0.001). Cage location (${\beta}=0.293$, p<0.001) and CW (${\beta}=-0.225$, p<0.001) were significantly correlated with cage subsidence. Conclusion : The cage location, CA, and CW seem to be important factors which result in the different-radiological outcomes between DLIF and OLIF.

• Journal of Korean Neurosurgical Society
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• 제37권6호
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• pp.422-426
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• 2005

Objective: Different types of interbody fusion cages are available for use in the surgical treatment of degenerative cervical diseases. The purpose of this study is to assess the technical feasibility, clinical efficacy and radiological results of intervertebral fusion with a carbon composite Osta-Pek frame cage (Co-Ligne AG, Switzerland) following anterior cervical discectomy. Methods: 41 patients (25males and 16females) with minimum 6months follow-up were included in the study. Disc height, cervical lordotic angle, segmental angle, and fusion rate were assessed by lateral radiographs. In this retrospective analysis, clinical outcome was assessed as evaluated according to Odom's criteria. Results: Fifty-four cages were implanted in 30 single-level, 9 two-level, and 2 three-level procedures. The mean disc height, cervical lordosis angle, segmental angle were $4.2{\pm}1.8mm,\;23.5{\pm}7.2^{\circ},\;2.3{\pm}3.3^{\circ}$ pre-operatively and $5.3{\pm}2.1mm,\;24.2{\pm}8.3^{\circ},\;3.8{\pm}3.5^{\circ}$ at 6months after the surgery. Six months after surgery, there was radiographic evidence of fusion in 92.7% (38/41) of the patients. According to Odom's criteria, 37 of 41 (90.2%) patients experienced good to excellent functional recovery. Conclusion: These clinical and radiological results suggest that the carbon composite Osta-Pek frame cages are safe and effective alternative to autologous bone graft after anterior cervical discectomy for treatment of degenerative cervical disease.

• Journal of Korean Neurosurgical Society
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• 제52권2호
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• pp.107-113
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• 2012

Objective : Various procedures have been introduced for anterior interbody fusion in degenerative cervical disc disease including plate systems with autologous iliac bone, carbon cages, and cylindrical cages. However, except for plate systems, the long-term results of other methods have not been established. In the present study, we evaluated radiologic findings for cylindrical cervical cages over long-term follow up periods. Methods : During 4 year period, radiologic findings of 138 patients who underwent anterior cervical fusion with cylindrical cage were evaluated at 6, 12, 24, and 36 postoperative months using plain radiographs. We investigated subsidence, osteophyte formation (anterior and posterior margin), cage direction change, kyphotic angle, and bone fusion on each radiograph. Results : Among the 138 patients, a minimum of 36 month follow-up was achieved in 99 patients (mean follow-up : 38.61 months) with 115 levels. Mean disc height was 7.32 mm for preoperative evaluations, 9.00 for immediate postoperative evaluations, and 4.87 more than 36 months after surgery. Osteophytes were observed in 107 levels (93%) of the anterior portion and 48 levels (41%) of the posterior margin. The mean kyphotic angle was $9.87^{\circ}$ in 35 levels showing cage directional change. There were several significant findings : 1) related subsidence [T-score (p=0.039) and anterior osteophyte (p=0.009)], 2) accompanying posterior osteophyte and outcome (p=0.05). Conclusion : Cage subsidence and osteophyte formation were radiologically observed in most cases. Low T-scores may have led to subsidence and kyphosis during bone fusion although severe neurologic aggravation was not found, and therefore cylindrical cages should be used in selected cases.

• 대한정형외과학회지
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• 제54권3호
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• pp.203-210
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• 2019

최소 침습적 외측 요추체간 유합술의 최신 지견에 대하여 알아보고자 하였다. 아직 도입된 지 얼마 되지 않았으나 근래에 각광받고 있는 최소 침습적 외측 요추체간 유합술에 대한 적응증 및 임상 결과와 유합률, 그리고 합병증에 대하여 문헌 고찰을 하였다. 외측 요추간 유합술의 적응증은 퇴행성 요추부 질환에서 고식적인 전방, 후방 추체간 유합술의 적응증과 거의 유사하다. 특히 척추관 협착증 및 퇴행성 척추 전방 전위증, 퇴행성 척추 변형, 퇴행성 추간판 질환, 인접 분절 퇴행성 질환에서 최소 침습적 수술로서 효과적이다. 또한 고식적 요추부 유합술과 비교하여 임상적 결과 및 유합률이 대등한 것으로 보고되고 있다. 하지만 수술 접근 및 과정에서 발생하는 수술 후 고관절 굴곡근 약화 및 신경 손상, 혈관 손상, 장기 손상, 케이지 침강, 위탈장 등의 비특이적 합병증들이 보고되고 있다. 외측 추체간 유합술은 고식적인 전방 또는 후방 추체간 유합술의 장점을 취합하고 단점을 보완한 수술이며 그 임상 결과나 유합률에도 큰 차이가 없어 퇴행성 요추부 질환의 치료에 최소 침습 수술로서 유용한 치료법이다. 하지만 수술 과정에서 발생하는 비특이적 합병증들을 개선해야 하는 것이 향후 과제이다.

• 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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.526-529
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• 2005

The purpose of this study is to investigate a loosening process of screws through a fatigue test. Therefore, it is attempted to perform an interbody fusion on porsine lumbar spine using cage and screws. From the results, it is found that the combining force in both of the cylinder and the taper type screws located on the upper-left first start to decrease and then the combination between a rod and screw loosens. In addition, it is investigated that the life of taper type screw increases 5.5% and this fact is coincident with the previous results.

• 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.

• Journal of Korean Neurosurgical Society
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• 제65권1호
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• pp.74-83
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• 2022

Objective : Oblique lumbar interbody fusion (OLIF) is a surgical technique that utilizes a large interbody cage to indirectly decompress neural elements. The position of the cage relative to the vertebral body could affect the degree of foraminal decompression. Previous studies determined the position of the cage using plain radiographs, with conflicting results regarding the influence of the position of the cage to the degree of neural foramen decompression. Because of the cage obliquity, computed tomography (CT) has better accuracy than plain radiograph for the measurement of the obliquely inserted cage. The objective of this study is to find the correlation between the position of the OLIF cage with the degree of indirect decompression of foraminal stenosis using CT and magnetic resonance imaging (MRI). Methods : We review imaging of 46 patients who underwent OLIF from L2-L5 for 68 levels. Segmental lordosis (SL) was measured in a plain radiograph. The positions of the cage were measured in CT. Spinal canal cross-sectional area (SCSA), and foraminal crosssectional area (FSCA) measurements using MRI were taken into consideration. Results : Patients' mean age was 69.7 years. SL increases 3.0±5.1 degrees. Significant increases in SCSA (33.3%), FCSA (43.7% on the left and 45.0% on the right foramen) were found (p<0.001). Multiple linear regression analysis shows putting the cage in the more posterior position correlated with more increase of FSCA and decreases SL correction. The position of the cage does not affect the degree of the central spinal canal decompression. Obliquity of the cage does not result in different degrees of foraminal decompression between right and left side neural foramen. Conclusion : Cage position near the posterior part of the vertebral body increases the decompression effect of the neural foramen while putting the cage in the more anterior position correlated with increases SL.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.971-972
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• 2013

• 대한정형외과학회지
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• 제54권3호
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• pp.237-243
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• 2019

목적: 경추간공 요추 추체간 유합술 후 단일 케이지의 후방이동의 위험인자들에 대해 알아보고자 한다. 대상 및 방법: 2015년 1월에서 2017년 1월까지 경추간공 요추간 유합술 시행한 환자들 중 1년 추시 가능한 48명(60개 추간판)의 환자들을 대상으로 후향적 연구를 시행하였다. 케이지의 후방이동이 있는 16명(17개 추간판)을 1군, 후방이동이 없는 32명(43개 추간판)을 2군으로 분류하였고, 의무기록과 방사선적 평가를 통해 인구학적 특징, 추간판 모양, 케이지 삽입된 요추 병변, 술 후 추간판 높이 변화, 추간판 내 케이지 삽입 위치 등을 분석하였다. 결과: 인구학적 인자 및 케이지 삽입된 요추 병변에 따른 각 군(1군 16명, 2군 32명) 간의 유의한 차이가 없었다. 1군에서 배(pear) 모양 추간판인 경우 9명으로 유의하게 더 많았고, 술 전, 후 추간판 높이 변화는 1.8 mm로 유의하게 낮았으며, 전후방 및 측면 사진상 케이지 위치가 각각 비 중앙(9명) 및 중앙(15명)인 경우 유의하게 더 많았다. 결론: 배모양 추간판, 적은 술 후 추간판 높이 변화, 전후방 및 측면 사진상 비중앙 부위 비전방 부위 케이지 삽입의 경우 후방이동의 발생 가능성이 높았다. 이를 토대로 술기에 참고하면 케이지 후방이동을 예방하는 데 도움이 될 것으로 생각된다.