• Journal of Korean Neurosurgical Society
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• v.29 no.4
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• pp.574-579
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• 2000

Chordomas are rare central nervous system tumors that are found predominantly in the sacrococcygeal(50%) and basiosphenoidal region(35%). Most of the remainder are related to the vertebral bodies and only 1 to 2% of them are known to occur in the thoracic vertebrae. A 15-year-old girl was admitted because of paraparesis. Three months prior to admission, she underwent a lumbar laminectomy at other hospital for the treatment of herniated lumbar disc but paraparesis became rather aggravated after the operation. At admission, MRI showed a low signal T1WI, high signal T2WI mass compressing the cord at T2 vertebral body. The tumor was subtotally removed via costotransversectomy but as the tumor was proven to be a chordoma, a second stage operation via anterior route was followed. At second operation, T2 corpectomy and T1-T3 plate fixation with autogeneous ileac bone graft was performed. Shortly after the operation, preoperative paraparesis disappeared completely and no evidence of tumor recurrence was noticed both clinically and radiologically for next 2 years. Spine surgery at cervicothoracic junction may be technically demanding due to anatomical complexity and hindering large vessels. The authers reviewed this case with special emphasis on the surgical procedure in this region.

• Journal of Korean Neurosurgical Society
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• v.41 no.6
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• pp.382-386
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• 2007

Objective : Various techniques of cervical laminoplasty have been developed to decompress the spinal canal in patients with multilevel cervical spondylotic myelopathy. This study compared the early surgical outcomes between unilateral open-door laminoplasty and midline splitting cervical laminoplasty. Materials and Methods : From March 2004 to August 2005, we performed cervical laminoplasty in 34 patients with cervical myelopathy. Of these patients, 24 were treated by unilateral open-door laminoplasty [open-door group] and 10 by midline splitting cervical laminoplasty [splitting group]. The mean duration of follow up was 9.2 months in the open-door group and 15.8 months in the splitting group. We retrospectively analyzed neurological outcomes using the Japanese Orthopedic Association [JOA] score, and compared the radiological changes between the two groups. Results : Postoperative JOA score and recovery rate were $13.29{\pm}4.01$ and $56.28{\pm}44.91%$ in the open-door group and $15.75{\pm}0.88$ and $72.69{\pm}19.99%$ in the splitting group. There was no statistical difference between the two groups [p>0.05]. Regarding the radiological assessment, the increase of postoperative axial canal area was $63.23{\pm}23.24%$ in the open-door group and $42.30{\pm}14.96%$ in the splitting group [p<0,05]. Conclusion : There was no statistical difference in the neurological outcome when the early surgical outcomes of the open-door group and the splitting group were compared. However, the open-door group showed wider cervical spinal canal areas than the splitting group.

• Journal of Korean Neurosurgical Society
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• v.60 no.4
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• pp.465-470
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• 2017

Objective : Magnetic resonance imaging (MRI) grading systems using sagittal images are useful for evaluation of lumbar foraminal stenosis. We evaluated whether such a grading system is useful as a diagnostic tool for surgery. Methods : Between July 2014 and June 2015, 99 consecutive patients underwent unilateral lumbar foraminotomy for lumbar foraminal stenosis. Surgically confirmed foraminal stenosis and the contralateral, asymptomatic neuroforamen were assessed based on a 4-point MRI grading system. Two experienced researchers independently evaluated the MR sagittal images. Interobserver agreement and intraobserver agreement were analyzed using ${\kappa}$ statistics. Results : The mean age of patients (54 women, 45 men) was 62.5 years. A total of 101 levels (202 neuroforamens) were evaluated. MRI grades for operated neuroforamens were as follows : Grade 0 in 0.99%, Grade 1 in 5.28%, Grade 2 in 14.85%, and Grade 3 in 78.88%. Interobserver agreement was moderate for operated neuroforamens (${\kappa}=0.511$) and good for asymptomatic neuroforamens (${\kappa}=0.696$). Intraobserver agreement by reader 1 for operated neuroforamens was good (${\kappa}=0.776$) and that for asymptomatic neuroforamens was very good (${\kappa}=0.831$). In terms of lumbar level, interobserver agreement for L5-S1 (${\kappa}=0.313$, fair) was relatively lower than the other level (${\kappa}=0.804$, very good). Conclusion : MRI grading system for lumbar foraminal stenosis is thought to be useful as a diagnostic tool for surgery in the lumbar spine; however, it is less reliable for symptomatic L5-S1 foraminal stenosis than for other levels. Thus, various clinical factors as well as the MRI grading system are required for surgical decision-making.

• Journal of Korean Neurosurgical Society
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• v.60 no.5
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• pp.567-576
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• 2017

Objective : Preoperative parameters including the T1 slope (T1S) and C2-C7 sagittal vertical axis (SVA) have been recognized as predictors of kyphosis after laminoplasty, which is accompanied by posterior neck muscle damage. The importance of preoperative parameters has been under-estimated in anterior cervical discectomy and fusion (ACDF) because there is no posterior neck muscle damage. We aimed to determine whether postoperative subsidence and pseudarthrosis could be predicted according to specific parameters on preoperative plain radiographs. Methods : We retrospectively analyzed 41 consecutive patients (male : female, 22 : 19; mean age, $51.15{\pm}9.25years$) who underwent ACDF with a stand-alone polyether-ether-ketone (PEEK) cage (>1 year follow-up). Parameters including SVA, T1S, segmental angle and range of motion (ROM), C2-C7 cervical angle and ROM, and segmental inter-spinous distance were measured on preoperative plain radiographs. Risk factors of subsidence and pseudarthrosis were determined using multivariate logistic regression. Results : Fifty-five segments (27 single-segment and 14 two-segment fusions) were included. The subsidence and pseudarthrosis rates based on the number of segments were 36.4% and 29.1%, respectively. Demographic data and fusion level were unrelated to subsidence. A greater T1S was associated with a lower risk of subsidence (p=0.017, odds ratio=0.206). A cutoff value of T1S<$28^{\circ}$ significantly predicted subsidence (sensitivity : 70%, specificity : 68.6%). There were no preoperative predictors of pseudarthrosis except old age. Conclusion : A lower T1S (T1S<$28^{\circ}$) could be a risk factor of subsidence following ACDF. Surgeons need to be aware of this risk factor and should consider various supportive procedures to reduce the subsidence rates for such cases.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.6
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• pp.995-999
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• 2004

Effects of liquefied calcium supplement on bone mineral density (BMD) and bone health index (osteocalcin, deoxypyridinoline) were investigated in 12 middle aged women. Middle aged women were arranged into 3 groups such as control, Ca500 and Ca750 by liquefied calcium supplement level. BMD was measured at the spine (vertebrae L2-L4). After 6 month, BMD of control group dropped but that of Ca750 were increased from 0.850 to 0.865. The increase in serum calcium and osteocalcin level, and the decrease in urine deoxypyridinoline level were observed in by calcium supplement groups. The bone health index of serum was changed as much as level of calcium supplement. The serum osteocalcin level of Ca750 significantly increased to 7.93 ng/mL after 6 months of calcium supplement. Although we didn't get any significant difference in BMD, we found that the liquefied calcium had no side effect and led effective change in bone health index. Hereafter, we suppose that the liquefied calcium will be available to develop healthy products for preventing osteoporosis.

• Korean Journal of Metals and Materials
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• v.49 no.12
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• pp.983-988
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• 2011

Failure analyses of the screws in spinal fixation devices were carried out. The fractured screws were retrieved from a patient who had spinal surgery in the thoracic vertebrae from number 10 to 15. The failure occurred one month after the removal of the braces. Microstructures and fracture surfaces were examined by optical and scanning electron microscopy. The microstructures of the screws corresponded to annealed Ti-6Al-4V bar. However, in the vicinity of the screw surface, there was an insufficient number of fine precipitates. Fracture surfaces showed typical fatigue failure modes. Regarding the fact that no machining defects were detected, fatigue crack initiation might have been caused by the lack of precipitates near the screw surfaces. Only the fourth of five fixed screws was severely stress-concentrated by the action of the spinal bones, while the stress of the 4th screw was decreased to half of its acceptable level when the screw was supplemented by one more, which might have been fixed in the 6th vertebra under the 5th position by the switching of its position. The stress simulation was conducted by ANSYS with 3D CAD of PRO/E in order to understand the stress concentration behavior and to provide an effective spinal surgery guide.

• Journal of Korean Medicine Rehabilitation
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• v.29 no.4
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• pp.89-100
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• 2019

Objectives We are going to analyze patient's medical and Korean medicine use trends after lumbar surgery, and examine the percentage of use of Korean medicine after surgery and its relevance to the medical care outcome after lumbar surgery. Methods Using 3% patients' sample data of the Health Insurance Review and Assessment Service, two groups were compared the treatment progress of the Korean Medicine treatment group and the untreated group after lumbar surgery by hierarchical logistic regression analysis. After hierarchical logistic regression analysis(including propensity scores), two groups were compared after lumbar surgery, the Korean Medicine treatment group within 50days and untreated group within 50days. Results Lumbar surgery was performed in 2750 patients in 2015. It was 3.72 that the risk(odds ratio) of finished treatment of patients treated without Korean Medicine, compared to patients with Korean Medicine. It was 0.12 that the risk of continuing treatment(odds ratio) of patients treated with Korean Medicine within 50 days, compared to patients treatment more than 50 days. Conclusions The ratio of Korean Medicine treatment after lumbar surgery was 14.8%. The group that did not have Korean Medicine showed a higher possibility of treatment termination than the group who did not. Among the groups treated with Korean Medicine, the early treatment group was more likely to end treatment than the late treatment group. Considering various situations in the medical environment, further studies such as prospective studies and long-term data analysis are considered to be necessary.

• Animal Systematics, Evolution and Diversity
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• v.8 no.2
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• pp.231-242
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• 1992

Samples of two species of genus Ratts(black rat, Rattus rasttus Linnaeus; common rat, Rattus norvegicus Berkenhaut) in Korea were trapped and their 31 morphometric charcters were analyzed statistically in order to determine the range of geographic variation within each species and the interspecific differences. In addition, chromosomal G-bands and C-bands were compared and the fragment patterns of mtDNA resulted from the digestion with restriction enzymes were also analyzed. Samples of black rats from six localities in Korea were similar with one another in their morphometric characters: in head and body length, length of tail vertebrae, conventional karyotype and C-bands, they are comparable to Rattus rattus tanezumi in Japan. Specimens of common rats from seven localities in Korea were similar with one another in their morphometric characters: in conventional karyotype, they are comparable to Rattus norvegicus caraco in eastern Asia. Common rats differ from black rats in their morphometric characteris, chromosomal karyotypes and mtDNA. It is confirmed that correct species name of black rat in Korea is Rattus rattus tanezumi Tempminck: species name of common rat in Korea is Rattus norvegicus caraco Pallas: the common rat is a species, which is distinct from the black rat.

• Journal of Korean Neurosurgical Society
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• v.64 no.6
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• pp.901-912
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• 2021

Objective : In the cervical spine, many surgical procedures have been developed to achieve optimal results for various disorders, including degenerative diseases, traumatic injury, and tumor. In this study, we report our experience and follow-up results with a new surgical technique for cervical spine entitled posterior floating laminotomy (PFL) in comparison with conventional laminectomy and fusion (LF). Methods : Data for 85 patients who underwent conventional LF (n=66) or PFL (n=19) for cervical spine disorders between 2012 and 2019 were analyzed. Radiological parameters, including cervical lordosis (CL), T1 slope (T1S), segmental lordosis (SL), and C2-7 sagittal vertical axis (SVA), were measured with lateral spine X-rays. Functional outcomes, comprising the modified Japanese Orthopaedic Association (mJOA), neck disability index (NDI), and visual analog scale (VAS) scores, were also measured. For the patients who underwent PFL, postoperative magnetic resonance image (MRI) was performed in a month after the surgery, and the degree of decompression was evaluated at the T2-weighted axial image, and postoperative computed tomography (CT) was conducted immediately and 1 year after the operation to evaluate the gutter fusion. Results : There was no difference in CL, T1S, SL, and C2-7 SVA between the groups but there was a difference in the preoperative and postoperative SL angles. The mean difference in the preoperative SL angle compared with that at the last follow-up was -0.3° after conventional LF and 4.7° after PFL (p=0.04), respectively. mJOA, NDI, and VAS scores showed significant improvements (p<0.05) during follow-up in both groups. In the PFL group, postoperative MRI showed sufficient decompression and postoperative CT revealed gutter fusion at 1 year after the operation. Conclusion : PFL is a safe surgical method which can preserve postoperative CL and achieve good clinical outcomes.

• Asian Spine Journal
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• v.12 no.6
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• pp.1078-1084
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• 2018

Study Design: Prospective observational study. Purpose: This prospective analysis aimed to evaluate the efficacy and bone-bonding rate of hybrid hydroxyapatite (HA) spacers in expansive laminoplasty. Overview of Literature: Various types of spacers or plates have been developed for expansive laminoplasty. Methods: Expansive open-door laminoplasty was performed in 146 patients with cervical myelopathy; 450 hybrid HA spacers and 41 autogenous bone spacers harvested from the spinous processes were grafted into the opened side of each lamina. The patients were followed up using computed tomography (CT), and their bone-bonding rates for hybrid HA and autogenous spacers, bone-fusion rates of the hinges of the laminae, and complications associated with the implants were then examined. Results: Clinical symptoms significantly improved in all patients, and no major complications related to the procedure were noted. The hybrid HA spacers exhibited sufficient bone bonding on postoperative CT. The hinges completely fused in over 95% patients within 1 year of the procedure. Only 4 spacers (0.9%) developed lamina sinking, and most expanded laminae maintained their positions without sinking or floating throughout the follow-up period. Conclusions: Hybrid HA spacers contributed to high bone-fusion rates of the spacers and hinges of the laminae, and no complications were associated with their use. Cervical laminoplasty with these spacers is safe and simple, and it yields sufficient fixation strength while ensuring sufficient bone bonding during the immediate postoperative period.