• Journal of Korean Neurosurgical Society
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• 제46권4호
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• pp.322-327
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• 2009

Objective : Posterior lumbar interbody fusion (PLIF) is considered to have the best theoretical potential in promoting bony fusion of unstable vertebral segments by way of a load sharing effect of the anterior column. This study was undertaken to investigate the efficacy of PLIF with cages in chronic degenerative disc disease with Modic degeneration (changes of vertebral end plate). Methods : A total of 597 patients underwent a PLIF with threaded fusion cages (TFC) from 1993 to 2000. Three-hundred-fifty-one patients, who could be followed for more than 3 years, were enrolled in this study. Patients were grouped into 4 categories according to Modic classification (no degeneration : 259, type 1 : 26, type 2 : 55, type 3 : 11). Clinical and radiographic data were evaluated retrospectively. Results : The clinical success rate according to the Prolo's functional and economic outcome scale was 86% in patients without degeneration and 83% in patients with Modic degeneration. The clinical outcomes in each group were 88% in type 1, 84% in type 2, and 73% in type 3. The bony fusion rate was 97% in patients without degeneration and 83% in patients with Modic degeneration. The bony fusion rate in each group was 81% in type 1, 84% in type 2, and 55% in type 3. The clinical success and fusion rates were significantly lower in patients with type 3 degeneration. Conclusion : The PLIF with TFC has been found to be an effective procedure for lumbar spine fusion. But, the clinical outcome and bony fusion rates were significantly low in the patients with Modic type 3. The authors suggest that PLIF combined with pedicle screw fixation would be the better for them.

• Journal of Korean Neurosurgical Society
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• 제53권1호
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• pp.49-51
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• 2013

A case of traumatic spondyloptosis of the cervical spine at the C6-C7 level is reported. The patient was treated succesfully with a anterior-posterior combined approach and decompression. The patient had good neurological outcome after surgery. A-51-year-old female patient was transported to our hospital's emergency department after a vehicle accident. The patient was quadriparetic (Asia D, MRC power 4/5) with severe neck pain. Plain radiographs, computerize tomography and spinal magnetic resonance imaging (MRI) showed C6-7 spondyloptosis and C5, C6 posterior element fractures. Gardner-Wells skeleton traction was applied. Spinal alignment was reachived by traction and dislocation was decreased to a grade 1 spondylolisthesis. Then the patient was firstly operated by anterior approach. Anterior stabilization and fusion was firstly achieved. Seven days after first operation the patient was operated by a posterior approach. The posterior stabilization and fusion was achieved. Postoperative lateral X-rays and three-dimensional computed tomography showed the physiological realignment and the correct screw placements. The patient's quadriparesis was improved significantly. Subaxial cervical spondyloptosis is a relatively rare clinical entity. In this report we present a summary of the clinical presentation, the surgical technique and outcome of this rarely seen spinal disorder.

• Journal of Communications and Networks
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• 제7권4호
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• pp.438-449
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• 2005

In this paper, we describes the information-theoretic approaches to sensor selection and sensor placement in sensor net­works for target localization and tracking. We have developed a sensor selection heuristic to activate the most informative candidate sensor for collaborative target localization and tracking. The fusion of the observation by the selected sensor with the prior target location distribution yields nearly the greatest reduction of the entropy of the expected posterior target location distribution. Our sensor selection heuristic is computationally less complex and thus more suitable to sensor networks with moderate computing power than the mutual information sensor selection criteria. We have also developed a method to compute the posterior target location distribution with the minimum entropy that could be achieved by the fusion of observations of the sensor network with a given deployment geometry. We have found that the covariance matrix of the posterior target location distribution with the minimum entropy is consistent with the Cramer-Rao lower bound (CRB) of the target location estimate. Using the minimum entropy of the posterior target location distribution, we have characterized the effect of the sensor placement geometry on the localization accuracy.

• Journal of Korean Neurosurgical Society
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• 제30권3호
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• pp.358-365
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• 2001

Objectives : Although posterior lumbar fusion operations had been reported to accelerate spinal degeneration, there have been only a few studies for their biomechanical effects. We have studied the change of motion range at the vertebral joint one level above the fusion(UVJ) in pedicle screw fixation group(PSF)(n=13) where facet capsule was destroyed and in posterior lumbar interbody fusion group(PLIF)(n=8) where it was spared. Patients and Methods : The patients were divided into early(3 to 6 months) and late(over 12 months) according to postoperative follow-up period. The flexion, extension and flexion-extension angles(FA, EA, FEA) were measured at the UVJ with pre-operative, early and late post-operative films. Results : Mean age and male to female ratio were $52.7{\pm}9.3$ and 1 : 3.2. Mean follow-up periods were $144.1{\pm}30.0$ and $528.8{\pm}160.3$ days in early and late groups, respectively. The FEA and FA in the late PSF($11.8{\pm}3.1$, $8.5{\pm}2.9$) were significantly greater than pre-operative angles($7.8{\pm}3.9$, $5.1{\pm}3.7$)(p<0.01, p<0.05). All angles in the PLIF showed no significant changes with time. The FEA and FA in the late PSF($11.8{\pm}3.1$, $8.5{\pm}2.9$) were significantly greater than those of the late PLIF($7.6{\pm}2.3$, $3.4{\pm}2.0$)(p<0.01, p<0.001). All angles at early follow-up period were similar between PSF and PLIF. The EA showed no significant change in relation with follow-up period or fusion method. Conclusion : As a result, the facet capsule injury in pedicle screw fixation seems to be related with increased flexion angle or degeneration of the adjacent joint above the fused vertebra in the late phase.

• Journal of Korean Neurosurgical Society
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• 제48권4호
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• pp.335-341
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• 2010

Objective : Anterior cervical corpectomy with fusion (ACF) or laminoplasty may be associated with substantial number of complications for treating multilevel cervical ossification of the posterior longitudinal ligament (OPLL) with significant cord compression. For more safe decompression and stabilization in multilevel cervical OPLL with prominent cord compression, we propose circumferential cervical surgery (selective ACF and laminoplasty) based on our favorable experience. Methods : Twelve patients with cervical myelopathy underwent circumferential cervical surgery and all patients showed multilevel OPLL with Signal change of the spinal cord on magnetic resonance imaging (MRI). A retrospective review of clinical, radiological. and surgical data was conducted. Results : There were 9 men and 3 women with mean age of 56.7 years and a mean follow up period of 15.6 months. The average corpectomy level was 1.16 and laminoplasty level was 4.58. The average Japanese Orthopedic Association score for recovery was 5.1 points and good clinical results were obtained in 11 patients (92%) (p < 0.05). The average space available for the cord improved from 58.2% to 87.9% and the average Cobb's angle changed from 7.63 to 12.27 at 6 months after operation without failure of fusion (p < 0.05). Average operation time was 8.36 hours, with an estimated blood loss of 760 mL and duration of bed rest of 2.0 days. There were no incidences of significant surgical complications, including wound infection. Conclusion : Although the current study examined a small sample with relatively short-term follow-up periods, our study results demonstrate that circumferential cervical surgery is considered favorable for safety and effectiveness in multilevel OPLL with prominent cord compression.

• Journal of Korean Neurosurgical Society
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• 제48권1호
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• pp.37-45
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• 2010

Objective : Craniovertebral junction (CVJ) consists of the occipital bone that surrounds the foramen magnum, the atlas and the axis vertebrae. The mortality and morbidity is high for irreducible CVJ lesion with cervico-medullary compression. In a clinical retrospective study, the authors reviewed clinical and radiographic results of occipitocervical fusion using a various methods in 32 patients with CVJ instability. Methods : Thirty-two CVJ lesions (18 male and 14 female) were treated in our department for 12 years. Instability resulted from trauma (14 cases), rheumatoid arthritis (8 cases), assimilation of atlas (4 cases), tumor (2 cases), basilar invagination (2 cases) and miscellaneous (2 cases). Thirty-two patients were internally fixed with 7 anterior and posterior decompression with occipitocervical fusion, 15 posterior decompression and occipitocervical fusion with wire-rod, 5 C1-2 transarticular screw fixation, and 5 C1 lateral mass-C2 transpedicular screw. Outcome (mean follow-up period, 38 months) was based on clinical and radiographic review. The clinical outcome was assessed by Japanese Orthopedic Association (JOA) score. Results : Nine neurologically intact patients remained same after surgery. Among 23 patients with cervical myelopathy, clinical improvement was noted in 18 cases (78.3%). One patient died 2 months after the surgery because of pneumonia and sepsis. Fusion was achieved in 27 patients (93%) at last follow-up. No patient developed evidence of new, recurrent, or progressive instability. Conclusion : The authors conclude that early occipitocervical fusion to be recommended in case of reducible CVJ lesion and the appropriate decompression and occipitocervical fusion are recommended in case of irreducible craniovertebral junction lesion.

• Journal of Korean Neurosurgical Society
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• 제42권3호
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• pp.179-183
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• 2007

Objective : Posterior arthrodesis in atlantoaxial instability has been performed using various posterior C1-2 wiring techniques. Recently, transarticular screw fixation (TASF) technique was introduced to achieve significant immediate stability of the C1-2 joint complex. The purpose of this study is to assess the clinical outcomes associated with posterior C1-2 TASF for the patient of atlantoaxial instability. Methods : We retrospectively reviewed data obtained from 17 patients who underwent C1-2 TASF and supplemented Posterior wiring technique (PWT) with graft between 1994 and 2005. There were 8 men and 9 women with a mean age of 43.5 years (range, 12-65 years). An average follow-up was 26 months (range, 15-108 months). Results : Successful fusions were achieved in 16 of 17 (94%). The pain was improved markedly (3 patients) or resolved completely (14 patients). There was no case of neurological deterioration, hypoglossal nerve injury, or vertebral artery injury. Progression of spinal deformity, screw pullout or breakage, and neurological or vascular complications did not occur. Conclusion : The C1-2 TASF with supplemental wiring provided a high fusion rate. Our result demonstrates that C1-2 TASF supplemented by PWT is a safe and effective procedure for atlantoaxial instability. Preoperative evaluation and planning is mandatory for optimal safety.

• Journal of Korean Neurosurgical Society
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• 제29권9호
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• pp.1262-1266
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• 2000

Objective : Flat back syndrome constitutes a syndrome complex characterized by the loss of normal lumbar lordosis. Various techniques of correction for flat back syndrome have been reported. Posterior extension osteotomy has certain drawbacks. Forceful hyperextension of the spine may result in vascular complications such as rupture of the aorta or the inferior vena cava and stretching of superior mesenteric artery, and pseudoarthrosis. We describe a rationale and technique of transvertebral posterior extension osteotomy to avoid complications of posterior extension osteotomy and to achieve an correction of 30 degrees of flat back syndrome. Method : A 63-year-old woman with degenerative lumbar kyphosis presented with low back pain, thigh pain, knee pain and walking difficulty. Transpedicular fixation from L1 vertebra to S1 vertebra was accomplished for lumbar degenerative kyphosis. After 6 months, the patient presented with flat back syndrome. A second operation was performed with transvertebral posterior extension osteotomy. Result : With short segemental fusion, early bone fusion and correction of 30 degrees were achieved. Conclusion : Transvertebral posterior extension osteotomy provide an 30-60 degrees of correction of flat back syndrome. This technique is considered to be good method for the revision of lumbar degenerative kyphosis.

• 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.

• 센서학회지
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• 제28권5호
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• pp.277-283
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• 2019

In this paper, we propose a distributed fusion estimation for sensor networks using a receding horizon strategy. Communication channels were modelled as Markov jump systems, and a posterior probability distribution for communication channel characteristics was calculated and incorporated into the filter to allow distributed fusion estimation to handle path loss observation situations automatically. To implement distributed fusion estimation, a Kalman-Consensus filter was then used to obtain the average consensus, based on the estimates of sensors randomly distributed across sensor networks. The advantages of the proposed algorithms were then verified using a large-scale sensor network example.