• Journal of Korean Neurosurgical Society
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• v.40 no.1
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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.

• Journal of the Korean Orthopaedic Association
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• v.54 no.3
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• pp.237-243
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• 2019

Purpose: To analyze the risk factors for posterior migration of a single cage after transforminal lumbar interbody fusion (TLIF). Materials and Methods: This study was conducted retrospectively on 48 patients (60 discs) who were followed-up for 1 year after TLIF from January 2015 to January 2017. The patients were divided into two groups: group 1 containing 16 patients (17 discs) with cage migration and group 2 containing 32 patients (43 discs) without it. Information related to cage migration, such as the demographic factors, shape of disc, level and location of the cage inserted, and disc height change, was acquired from the medical records and radiologic images, and the possibility for generating posterior migration of cage was evaluated statistically. Results: The demographic factors and cage-inserted level were similar in the two groups (16 patients in group 1, 32 patients in group 2). In the migration group, number of patients with a pear-type disc, 9 patients, was significantly larger; the disc height change, 1.8 mm, was significantly smaller; and the cage was located frequently on non-center in the anteriorposterior view and center in the lateral view in 9 and 15 out of 16 patients, respectively. Conclusion: A pear-type disc shape, small disc height change, cage with non-center on the anteriorposterior view and non-anterior on the lateral view are the risk factors for posterior migration. These factors are important for preventing posterior migration of the cage.

• Journal of Korean Neurosurgical Society
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• v.65 no.1
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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.

• Journal of Korean Neurosurgical Society
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• v.60 no.6
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• pp.755-762
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• 2017

Objective : The purpose of this study is to describe the detailed surgical technique and short-term clinical and radiological outcomes of lateral lumbar interbody fusion (LLIF) and in situ lateral screw fixation using a conventional minimally invasive screw fixation system (MISF) for revision surgery to treat rostral lumbar adjacent segment disease. Methods : The medical and radiological records were retrospectively reviewed. The surgery was indicated in 10 consecutive patients with rostral adjacent segment stenosis and instability. After the insertion of the interbody cage, lateral screws were inserted into the cranial and caudal vertebra using the MISF through the same LLIF trajectory. The radiological and clinical outcomes were assessed preoperatively and at 1, 3, 6, and 12 months postoperatively. Results : The median follow-up period was 13 months (range, 3-48 months). Transient sensory changes in the left anterior thigh occurred in 3 patients, and 1 patient experienced subjective weakness; however, these symptoms normalized within 1 week. Back and leg pain were significantly improved (p<0.05). In the radiological analysis, both the segmental angle at the operated segment and anterior disc height were significantly increased. At 6 months postoperatively, solid bony fusion was confirmed in 7 patients. Subsidence and mechanical failure did not occur in any patients. Conclusion : This study demonstrates that LLIF and in situ lateral screw fixation may be an alternative surgical option for rostral lumbar adjacent segment disease.

• Journal of Korean Neurosurgical Society
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• v.55 no.3
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• pp.142-147
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• 2014

Objective : A thoracolumbar burst fracture is usually unstable and can cause neurological deficits and angular deformity. Patients with unstable thoracolumbar burst fracture usually need surgery for decompression of the spinal canal, correction of the angular deformity, and stabilization of the spinal column. We compared two struts, titanium mesh cages (TMCs) and expandable cages. Methods : 33 patients, who underwent anterior thoracolumbar reconstruction using either TMCs (n=16) or expandable cages (n=17) between June 2000 and September 2011 were included in this study. Clinical outcome was measured by visual analogue scale (VAS), American Spinal Injury Association (ASIA) scale and Low Back Outcome Score (LBOS) for functional neurological evaluation. The Cobb angle, body height of the fractured vertebra, the operation time and amount of intra-operative bleeding were measured in both groups. Results : In the expandable cage group, operation time and amount of intraoperative blood loss were lower than that in the TMC group. The mean VAS scores and LBOS in both groups were improved, but no significant difference. Cobb angle was corrected higher than that in expandable cage group from postoperative to the last follow-up. The change in Cobb angles between preoperative, postoperative, and the last follow-up did not show any significant difference. There was no difference in the subsidence of anterior body height between both groups. Conclusion : There was no significant difference in the change in Cobb angles with an inter-group comparison, the expandable cage group showed better results in loss of kyphosis correction, operation time, and amount of intraoperative blood loss.

• Journal of Biomedical Engineering Research
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• v.38 no.1
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• pp.9-15
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• 2017

Recently, flexible cages have been introduced in an attempt to absorb and reduce the abnormal load transfer along the anterior parts of the spine. They are designed to be used with the pedicle screw systems to allow some mobility at the index level while containing ROM at the adjacent level. In this study, a finite element (FE) study was performed to assess biomechanical efficacies of the flexible cage when combined with pedicle screws with flexible rods. The post-operated models were constructed by modifying the L4-5 of a previously-validated 3-D FE model of the intact lumbar spine (L2-S1): (1) Type 1, flexible cage only; (2) Type 2, pedicle screws with flexible rods; (3) Type 3, interbody fusion cage plus pedicle screws with rigid rods; (4) Type 4, interbody fusion cage plus Type 2; (5) Type 5, Type 1 plus Type 2. Flexion/extension of 10 Nm with a compressive follower load of 400N was applied. As compared to the Type 3 (62~65%) and Type 4 (59~62%), Type 5 (53~55%) was able to limit the motion at the operated level effectively, despite moderate reduction at the adjacent level. It was also able to shift the load back to the anterior portions of the spine thus relieving excessively high posterior load transfer and to reduce stress on the endplate by absorbing the load with its flexible shape design features. The likelihood of component failure of flexble cage remained less than 30% regardless of loading conditions when combined with pedicle screws with flexible rods. Our study demonstrated that flexible cages when combined with posterior dynamic system may help reduce subsidence of cage and degeneration process at the adjacent levels while effectively providing stability at the operated level.

• Journal of the Korean Orthopaedic Association
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• v.54 no.3
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• pp.203-210
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• 2019

The aim of this review was to evaluate minimally invasive lateral lumbar interbody fusion on the latest update. Lumbar interbody fusion was introduced recently. This study performed, a literature review of the indications, clinical outcomes, fusion rate, and complications regarding recently highlighted minimally invasive lateral lumbar interbody fusion. The indications of lateral lumbar interbody fusion are similar to the conventional anterior and posterior interbody fusion in degenerative lumbar diseases. In particular, lateral lumbar interbody fusion is an effective minimally invasive surgery in spinal stenosis, degenerative spondylolisthesis, degenerative adult deformity, degenerative disc disease and adjacent segment disease. In addition, the clinical outcomes and fusion rates of lateral lumbar interbody fusion are similar compared to conventional lumbar fusion. On the other hand, non-specific complications including hip flexor weakness, nerve injury, vascular injury, visceral injury, cage subsidence and pseudohernia have been reported. Lateral lumbar interbody fusion is a very useful minimally invasive surgery because it has advantages over conventional anterior and posterior interbody fusion without many of the disadvantages. Nevertheless, nonspecific complications during lateral lumbar interbody fusion procedure remain a challenge to be improved.

• Journal of Korean Neurosurgical Society
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• v.65 no.1
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• pp.96-106
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• 2022

Objective : The most common complication of anterior cervical discectomy and fusion (ACDF) is cage subsidence and maintenance of disc height affects postoperative clinical outcomes. We considered cage subsidence as an inappropriate indicator for evaluating preservation of disc height. Thus, this study aimed to consider patients with complications such as reduced total disc height compared to that before surgery and evaluate the relevance of several factors before ACDF. Methods : We retrospectively reviewed the medical records of 40 patients who underwent stand-alone single-level ACDF using a polyetheretherketone (PEEK) cage at our institution between January 2012 and December 2018. Our study population comprised 19 male and 21 female patients aged 24-70 years. The minimum follow-up period was 1 year. Twenty-seven patients had preoperative bone mineral density (BMD) data on dual-energy X-ray absorptiometry. Clinical parameters included sex, age, body mass index, smoking history, and prior medical history. Radiologic parameters included the C2-7 cobb angle, segmental angle, sagittal vertical axis, disc height, and total intervertebral height (TIH) at the preoperative and postoperative periods. Cage decrement was defined as the reduction in TIH at the 6-month follow-up compared to preoperative TIH. To evaluate the bone quality, Hounsfield unit (HU) value was calculated in the axial and sagittal images of conventional computed tomography. Results : Lumbar BMD values and cervical HU values were significantly correlated (r=0.733, p<0.001). We divided the patients into two groups based on cage decrement, and 47.5% of the total patients were regarded as cage decrement. There were statistically significant differences in the parameters of measuring the HU value of the vertebra and intraoperative distraction between the two groups. Using these identified factors, we performed a receiver operating characteristic (ROC) curve analysis. Based on the ROC curve, the cut-off point was 530 at the HU value of the upper cortical and cancellous vertebrae (p=0.014; area under the curve [AUC], 0.727; sensitivity, 94.7%; specificity, 42.9%) and 22.41 at intraoperative distraction (p=0.017; AUC, 0.722; sensitivity, 85.7%; specificity, 57.9%). Using this value, we converted these parameters into a bifurcated variable and assessed the multinomial regression analysis to evaluate the risk factors for cage decrement in ACDF. Intraoperative distraction and HU value of the upper vertebral body were independent factors of postoperative subsidence. Conclusion : Insufficient intraoperative distraction and low HU value showed a strong relationship with postoperative intervertebral height reduction following single stand-alone PEEK cage ACDF.

• Journal of Korean Neurosurgical Society
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• v.42 no.4
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• pp.317-325
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• 2007

Objective : The purpose of the study was to determine the clinical effects of anterior radical debridement on a series of patients with spontaneous spinal infection. Methods : We retrospectively analyzed the clinical characteristics of 32 patients who underwent surgical treatment from January 2000 to December 2005 in our department. The average follow-up Period was 33.4 months (range, 6 to 87 months). Thirty-two patients presented with the following : 23 cases with pyogenic spondylitis, eight with tuberculous spondylitis and one with fungal spondylitis. The indications for surgery were intractable pain, failure of medical management, neurological impairment with or without an associated abscess, vertebral destruction causing spinal instability and/or segmental kyphosis. Results : The study included 15 (46.9%) males and 17 (53.1%) females ranging in age from 26 to 75 years (mean, 53.1 years). Diabetes mellitus (DM) and pulmonary Tbc were the most common predisposing factors for pyogenic spondylitis and tuberculous spondylitis. Staphylococcus aureus (13%) was the main organism isolated. The most prevalent location was the lumbar spine (75%). Changes in the pain score, Frankel's classification, and laboratory parameters demonstrated a significant clinical improvement in all patients. However, there were recurrent infections in two patients with tuberculous spondylitis and inappropriate debridement and intolerance of medication and noncompliance. Autologous rib, iliac bone and allograft(fibular) were performed in most patients. However, 10 patients were grafted using a titanium mesh cage after anterior radical debridement. There were no recurrent infections in the 10 cases using the mesh cage with radical debridement. Conclusion : The findings of this study indicate that surgery based on appropriate surgical indications is effective for the control of spinal infection and prevention of recurrence with anterior radical debridement, proper drug use and abscess drainage.

• Journal of Korean Neurosurgical Society
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• v.64 no.3
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• pp.447-459
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• 2021

Objective : Oblique lateral interbody fusion (OLIF) is becoming the preferred treatment for degenerative lumbar diseases. As beginners, we performed 143 surgeries over 19 months. In these consecutive cases, we analyzed the learning curve and reviewed the complications in our experience. Methods : This was a retrospective study; however, complications that were well known in the previous literature were strictly recorded prospectively. We followed up the changes in estimated blood loss (EBL), operation time, and transient psoas paresis according to case accumulation to analyze the learning curve. Results : Complication-free patients accounted for 43.6% (12.9%, early stage 70 patients and 74.3%, late stage 70 patients). The most common complication was transient psoas paresis (n=52). Most of these complications occurred in the early stages of learning. C-reactive protein normalization was delayed in seven patients (4.89%). The operation time showed a decreasing trend with the cases; however, EBL did not show any significant change. Notable operation-induced complications were cage malposition, vertebral body fracture, injury to the ureter, and injury to the lumbar vein. Conclusion : According to the learning curve, the operation time and psoas paresis decreased. It is important to select an appropriately sized cage along with clear dissection of the anterior border of the psoas muscle to prevent OLIF-specific complications.