• Journal of Korean Medicine Rehabilitation
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• v.20 no.2
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• pp.1-15
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• 2010

Objectives : This study was performed to evaluate the effects of root of Cibotii rhizoma(CR) ethanol extract on the tissue and neuronal damage of the spinal cord injury(SCI). Methods : SCI was induced by mechanical contusion following laminectomy of 10th thoracic vertebra in Sprague-Dawley rats. CR was orally given once a day for 7 days after SCI. Tissue damage and nerve fiber degeneration were examined with cresyl violet and luxol fast blue(LFS) histochemistry. HSP72(as neuronal damage marker), MAP2(as nerve fiber degeneration marker), c-Fos(immediate early gene), and Bax(pro-apoptotic molecule) expressions were examined using immuno-histochemistry. Individual immuno-positive cells expressing HSP72, MAP2, c-Fos and Bax were observed on the damaged level and the upper thoracic and lower lumbar spinal segments. Results : 1. CR reduced degeneration of nerve fibers and motor neuron shrinkage in the ventral horn of the lower lumbar spinal segment, but generally it did not seem to ameliorate the tissue injury following SCI. 2. CR reduced demyelination in the ventral and lateral funiculus of the lower lumbar spinal segment. 3. CR reduced HSP72 expression on the neurons in the peri-central canal gray matter adjacent to the damaged region. 4. CR strengthened MAP2 expression on the motor neurons in the ventral horn and on nerve fibers in the lateral funiculus of the lower lumbar spinal segment. 5. CR reduced c-Fos positive cells in the peri-lesion and the dorsal horn of the damaged level and in the ventral horn of the lower lumbar spinal segment. 6. CR reduced Bax positive cells in the peri-lesion and the dorsal horn of the damaged level and in the ventral horn of the lower lumbar spinal segment. Conclusions : These results suggest that CR plays an inhibitory role against secondary neuronal damage and nerve fiber degeneration. following SCI.

• Journal of Korean Neurosurgical Society
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• v.44 no.4
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• pp.217-221
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• 2008

Objective : Although anterior cervical discectomy and fusion (ACDF) is the standard treatment for degenerative cervical disc disease, concerns regarding adjacent level degeneration and loss of motion have suggested that arthroplasty may be a better alternative. We have compared clinical and radiological results in patients with cervical disc herniations treated with arthroplasty and ACDF. Methods : We evaluated 53 patients treated for cervical disc herniations with radiculopathy, 21 of whom underwent arthroplasty and 32 of whom underwent ACDF. Clinical results included the Visual Analogue Scale (VAS) score for upper extremity radiculopathy, neck disability index (NDI), duration of hospital stay and convalescence time. All patients were assessed radiologically by measuring cervical lordosis, segmental lordosis and segmental range-of-movement (ROM) of operated and adjacent disc levels. Results : Mean hospital stay (5.62 vs. 6.26 days, p<0.05) and interval between surgery and return to work (1.10 vs 2.92 weeks, p<0.05) were significantly shorter in the arthroplasty than in the fusion group. Mean NDI and extremity VAS score improved after 12 months in both groups. Although it was not significant, segmental ROM of adjacent levels was higher in the fusion group than in the arthroplasty group. And, segmental motion of operated levels in arthroplasty group maintained more than preoperative value at last follow up. Conclusion : Although clinical results were similar in the two groups, postoperative recovery was significantly shorter in the arthroplasty group. Although it was not significant, ROM of adjacent segments was less in the arthroplasty group. Motion of operated levels in arthroplasty group was preserved at last follow up.

• Journal of Korean Neurosurgical Society
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• v.29 no.11
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• pp.1456-1460
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• 2000

Objectives : Transpedicular screw fixation has become an important method for internal fixation in variety of disorders. However, acceleration of degeneration at the adjacent segment in any follow. The goal of this study is to review the change of motion ranges of vertebral joints adjacent to fused level in lumbar spine. Methods : This study consists of 22 patients with degenerative spinal instability. Treatment of spinal instability includes posterior fusion with transpedicular screw fixation or transpedicular screw fixation with posterior lumbar interbody fusion. The flexion-extension angle(FEA) was measured from dynamic views of lumbar spine taken both at preoperative and post operative period. Results : The FEA of upper vertebral joint adjacent(FEA-u) to a fused L4-5 level was increased(p＝0.010). The FEA-u was increased in case of L5-S1 fusion(p＝0.025). The change of FEA-u in case of L5-S1 fusion was greater than that in L4-5 fusion(p＝0.013). Conclusion : After L4-5 fusion, there seems to be more meaningful increase in FEA of L3-4 than that of L5-S1. The reason may be due to the damage of L3-4 facet joints during the operation, the other possible explanation may be the anatomical stability of L5-S1 vertebral joint. The change of FEA-u of L5-S1 fusion is increased more than that of L4-5 fusion. Because there are compensations in the adjacent vertebrae both above and below the fused L4-5, the compensatory motion in FEA-u of L5-S1 fusion was greater than that of the L4-5 fusion.

• Journal of Korean Neurosurgical Society
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• v.58 no.3
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• pp.225-230
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• 2015

Objective : The clinical outcomes according to the radiological results after cervical total disc replacement (TDR) are not well established. Here, the authors reviewed the clinical results according to the asymmetry in radiographs. Methods : This retrospective analysis included patients after TDR ($Mobi-C^{(R)}$ disc) with at least 12 months follow up, and the clinical and radiological data were obtained preoperatively and postoperatively for 12 months. Clinical outcome measures numerical rating scale (NRS) score for neck pain, visual analog scale (VAS) for arm pain, and the Oswestry disability index (ODI) value. The asymmetries of TDRs were evaluated on the anterior-posterior (AP) and the lateral radiographs, and the radiographic adjacent segment degenerations were evaluated for 12 months. Results : A total of 24 patients (one level cervical TDR; 10 male and 14 female; aged $41.50{\pm}8.35years$) were included in this study. The clinical results including NRS for neck pain, VAS for arm pain, and ODIs were similar between the normal and asymmetrized TDRs in AP and lateral radiographs. The radiographic adjacent segment degenerations were significantly increased in deviated TDRs (AP >10 mm asymmetry and lateral>10 mm asymmetry). Conclusion : Asymmetrical location of TDR is not related to the clinical outcomes, but related to the risk of radiographic adjacent disc segment degeneration.

• 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 Korean Neurosurgical Society
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• v.47 no.6
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• pp.446-453
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• 2010

Objective : The purpose of this study was to analyze the biomechanical effects of three different constrained types of an artificial disc on the implanted and adjacent segments in the lumbar spine using a finite element model (FEM). Methods : The created intact model was validated by comparing the flexion-extension response without pre-load with the corresponding results obtained from the published experimental studies. The validated intact lumbar model was tested after implantation of three artificial discs at L4-5. Each implanted model was subjected to a combination of 400 N follower load and 5 Nm of flexion/extension moments. ABAQUS$^{TM}$ version 6.5 (ABAQUS Inc., Providence, RI, USA) and FEMAP version 8.20 (Electronic Data Systems Corp., Plano, TX, USA) were used for meshing and analysis of geometry of the intact and implanted models. Results : Under the flexion load, the intersegmental rotation angles of all the implanted models were similar to that of the intact model, but under the extension load, the values were greater than that of the intact model. The facet contact loads of three implanted models were greater than the loads observed with the intact model. Conclusion : Under the flexion load, three types of the implanted model at the L4-5 level showed the intersegmental rotation angle similar to the one measured with the intact model. Under the extension load, all of the artificial disc implanted models demonstrated an increased extension rotational angle at the operated level (L4-5), resulting in an increase under the facet contact load when compared with the adjacent segments. The increased facet load may lead to facet degeneration.

• Journal of Korean Neurosurgical Society
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• v.49 no.4
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• pp.212-216
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• 2011

Objective : It is well known that plate-to-disc distance (POD) is closely related to adjacent-level ossification following anterior cervical plate placement. The study was undertaken to compare the outcomes of two different anterior cervical plating methods for degenerative cervical condition. Specifically, the new method involves making holes for plate screws first with an air drill and then choosing a plate size. The other method was standard, that is, decide on the plate size first, locate the plate on the anterior vertebral body, and then drilling the screw holes. Our hypothesis was that the new technical tip may increase POD as compared with the standard anterior cervical plating procedure. Methods : We retrospectively reviewed 49 patients who had a solid fusion after anterior cervical arthrodesis with a plate for the treatment of cervical disc degeneration. Twenty-three patients underwent the new anterior cervical plating technique (Group A) and 26 patients underwent the standard technique (Group B). POD and ratios between POD to anterior body heights (ABH) were measured using postoperative lateral radiographs. In addition, operating times and clinical results were reviewed in all cases. Results : The mean durations of follow-up were $16.42{\pm}5.99$ (Group A) and $19.83{\pm}6.71$ (Group B) months, range 12 to 35 months. Of these parameters mentioned above, cephalad POD (5.43 versus 3.46 mm, p=0.005) and cephalad POD/ABH (0.36 versus 0.23, p=0.004) were significantly greater in the Group A, whereas operation time for two segment arthrodesis (141.9 versus 170.6 minutes, p=0.047) was significantly lower in the Group A. There were no significant difference between the two groups in caudal POD (5.92 versus 5.06 mm), caudal POO/ABH (0.37 versus 0.32) and clinical results. Conclusion : The new anterior cervical plating method represents an improvement over the standard method in terms of cephalad plate-to-disc distance and operating time.

• Journal of Korean Neurosurgical Society
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• v.54 no.6
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• pp.496-500
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• 2013

Objective : To evaluate the successful fusion rate in postmenopausal women with single-level anterior cervical discectomy and successful fusion (ACDF) and identify the significant factors related to bone successful fusion in pre- and postmenopausal women. Methods : From July 2004 to December 2010, 108 consecutive patients who underwent single-level ACDF were prospectively selected as candidates. Among these, the charts and radiological data of 39 women were reviewed retrospectively. These 39 women were divided into two groups : a premenopausal group (n=11) and a postmenopausal group (n=28). To evaluate the significant factors affecting the successful fusion rate, the following were analyzed : the presence of successful fusion, successful fusion type, age, operated level, bone mineral density, graft materials, stand-alone cage or plating with autologous iliac bone, subsidence, adjacent segment degeneration, smoking, diabetes mellitus, and renal disease. Results : The successful fusion rates of the pre- and postmenopausal groups were 90.9% and 89.2%, respectively. There was no significant difference in the successful fusion rate or successful fusion type between the two groups. In the postmenopausal group, three patients (10.8%) had successful fusion failure. In the postmenopausal group, age and subsidence significantly affected the successful fusion rate (p=0.016 and 0.011, respectively), and the incidence of subsidence in patients with a cage was higher than that in patients with a plate (p=0.030). Conclusion : Menopausal status did not significantly affect bone successful fusion in patients with single-level ACDF. However, in older women with single-level ACDF, the combination of use of a cage and subsidence may unfavorably affect successful fusion.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.2
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• pp.130-136
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• 2010

For stability analysis of the lumbar spine, the hypothesis presented is that the disc has stress sensors driving feedback mechanism, which could react to the imposed loads by adjusting the contraction of the muscles. Fusion in the motion segment of the lumbar spinal column is believed to alter the stability of the spinal column. To identify this effect finite element (FE) models combined with optimization technique was applied and quantify the role of each muscle and reaction forces in the spinal column with respect to the fusion level. The musculoskeletal FE model was consisted with detailed whole lumbar spine, pelvis, sacrum, coccyx and simplified trunk model. Vertebral body and pelvis were modeled as a rigid body and the rib cage was constructed with rigid truss element for the computational efficiency. Spinal fusion model was applied to L3-L4, L4-L5, L5-S1 (single level) and L3-L5 (two levels) segments. Muscle architecture with 46 local muscles was used as acting directions. Minimization of the nucleus pressure deviation and annulus fiber average axial stress deviation was selected for cost function. As a result, spinal fusion produced reaction changes at each motion segment as well as contribution of each muscle. Longissimus thoracis and psoas major muscle showed dramatic changes for the cases of L5-S1 and L3-L5 level fusion. Muscle force change at each muscle also generated relatively high nucleus pressure not only at the adjacent level but at another level, which can explain disc degeneration pattern observed in clinical study.

• Journal of Korean Neurosurgical Society
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• v.52 no.4
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• pp.359-364
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• 2012

Objective : Transpedicular screw fixation has some disadvantages such as postoperative back pain through wide muscle dissection, long operative time, and cephalad adjacent segmental degeneration (ASD). The purposes of this study are investigation and comparison of radiological and clinical results between interspinous fusion device (IFD) and pedicle screw. Methods : From Jan. 2008 to Aug. 2009, 40 patients underwent spinal fusion with IFD combined with posterior lumbar interbody fusion (PLIF). In same study period, 36 patients underwent spinal fusion with pedicle screw fixation as control group. Dynamic lateral radiographs, visual analogue scale (VAS), and Korean version of the Oswestry disability index (K-ODI) scores were evaluated in both groups. Results : The lumbar spine diseases in the IFD group were as followings; spinal stenosis in 26, degenerative spondylolisthesis in 12, and intervertebral disc herniation in 2. The mean follow up period was 14.24 months (range; 12 to 22 months) in the IFD group and 18.3 months (range; 12 to 28 months) in pedicle screw group. The mean VAS scores was preoperatively $7.16{\pm}2.1$ and $8.03{\pm}2.3$ in the IFD and pedicle screw groups, respectively, and improved postoperatively to $1.3{\pm}2.9$ and $1.2{\pm}3.2$ in 1-year follow ups (p<0.05). The K-ODI was decreased significantly in an equal amount in both groups one year postoperatively (p<0.05). The statistics revealed a higher incidence of ASD in pedicle screw group than the IFD group (p=0.029) Conclusion : Posterior IFD has several advantages over the pedicle screw fixation in terms of skin incision, muscle dissection and short operative time and less intraoperative estimated blood loss. The IFD with PLIF may be a favorable technique to replace the pedicle screw fixation in selective case.