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Effect of Modic Changes in Cervical Degenerative Disease
강경탁,손동욱,권오익,이수헌,황종욱,김동하,이준석,송근성 대한척추신경외과학회 2017 Neurospine Vol.14 No.2
Objective: Modic changes are signal intensity changes in adjacent vertebral bone marrow on magnetic resonance imaging. Few studies have investigated these changes with regard to the cervical spine. In this study, we investigated the associations between cervical degenerative disease and Modic changes. Methods: We conducted a retrospective collection of radiological data in patients with neck pain at Pusan National University Yangsan Hospital from January 2010 to December 2014. A total of 169 patients were included in this study. Disc herniation grade, disc space height and global cervical lordosis (C2-C7 Cobb angle) were measured and analyzed. If Modic changes were present, we recorded the Modic change type based on the literature, vertebral level, age, sex, and surgical requirement. Results: Sixty-six patients exhibited Modic changes in the cervical spine. Out of these 66 patients, Modic change type II (56 patients, 84.8%) and C5-6 vertebral level (23 patients, 34.8%) were the most predominant categories. Patients with Modic change showed worse outcomes in regard to disc herniation grade, disc space height and global cervical lordosis than patients without (p<0.01). Among 169 patients, 18 patients had undergone anterior cervical discectomy with fusion (ACDF). Patients with Modic changes (10 of 66 patients, 15.1%) had a greater probability of undergoing ACDF than those without (8 of 103 patients, 7.8%; p<0.01). Conclusion: Modic changes refer cervical degenerative changes, and incidence of ACDF is higher when the Modic changes are occurred.
강경탁,김성환,손주현,이영한,전흥재 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.
In this paper, we present a new validation method for subject-specific finite element (FE) modeling of the knee joint based on in vivo computed tomography (CT) and magnetic resonance imaging (MRI) data. Previously, several FE models have been developed for estimating the mechanical response of joint structures, where direct or indirect in vivo measurement is difficult or impossible. More recently, studies using MRI have provided clear visualization of the motion and deformation of the articular cartilage within the tibiofemoral (TF) joint space. Two methods have been introduced to validate in vivo subject-specific models: alignment of supine MRI with X-ray images and weight-bearing MRI. The size of the contact area between the femur and tibia was determined by computing the area of femoral cartilage that intersected the tibial cartilage. The result showed good agreement between non-weight bearing image aligned with X-ray and weight-bearing MRI images. This study may help to better define the relative importance of modeling validations for the development of subject-specific models.
Gait Cycle Comparions of Cruciate Sacrifice for Total Knee Design.-Explicit Finite Element
강경탁,전흥재,박준희,이광일,심영복,장주웅 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.
Joint kinematics and contact mechanics dictate the success of current total knee replacement (TKR) devices. Computational contact prediction is a feasible way of evaluating new TKR designs prior to physical testing and implementation. Previous finite element (FE)knee models have generally been used to predict stresses on contact areas and/or areas subjected to static or quasi-static loading. Explicit dynamic FE analyses have recently been used to effectively predict TKR kinematics and contact mechanics during dynamic loading conditions. In this study, we compared the functional load transmission and kinematic performance of two posterior-stabilized designs, standard and post-cam TKR versions, over a standardized loading cycle using three-dimensional contact finite element analysis. Our objective was to develop and experimentally validate an explicit FE TKR model that incorporates femoral-bearing articulations. Finite element-based computational contact pressure predictions were applied to gait cycles using both force-controlled and displacement-controlled inputs. A standard prosthesis showed a reduction in contact pressure compared with post-cam prosthesis components, as it redistributed the knee motion to two articulating interfaces with more linear motions at each interface. In this FE analysis, the wear of TKR bearings was dependent on kinematics at the articulating surfaces and on prosthesis design.
강경탁,손동욱,이수헌,송근성,성순기,이상원 대한척추신경외과학회 2017 Neurospine Vol.14 No.3
Objective: Serum C-reactive protein (CRP) concentrations and white blood cell (WBC) count are commonly used to identify postoperative wound infections. We investigated whether changes in serum CRP levels and WBC counts actually differed between patients undergoing revision spinal fusion surgery and those undergoing a primary fusion. Methods: Patients who underwent posterolateral fusion (PLF) surgery at Pusan National University Yangsan Hospital between October 2013 and April 2015 were considered for this study. Sixty-seven patients with primary lumbar PLF (pPLF) and 21 with revision PLF (rPLF) were enrolled. A retrospective assessment of preoperative and postoperative CRP levels and WBC count was undertaken. Also, we gathered peak CRP day, and CRP normalization days. Comorbidity data were also obtained to evaluate any effects on the course of CRP and WBC count postoperatively. Results: CRP levels peaked at 3 days after surgery. The maximum CRP values recorded for each group: 4.17 (standard deviation [SD], 4.18) mg/dL and 4.88 (SD, 3.03) mg/dL for pPLF and rPLF. This difference was not statistically significant (p=0.24). A rapid fall in CRP within 5-9 days was observed for both groups. Conclusion: Out of our expectation, changes in CRP levels after spinal fusion surgery follow the same course regardless of whether it is a revision operation or not. Because of this result, both the primary PLF surgery and revision PLF surgery should be monitored using CRP in the similar way and the antibiotic administration should be determined.