• Journal of Korean Neurosurgical Society
• /
• 제52권5호
• /
• pp.452-458
• /
• 2012

Objective : In the present study, we evaluated the effect, safety and radiological outcomes of cervical hybrid surgery (cervical disc prosthesis replacement at one level, and interbody fusion at the other level) on the multilevel cervical degenerative disc disease (DDD). Methods : Fifty-one patients (mean age 46.7 years) with symptomatic multilevel cervical spondylosis were treated using hybrid surgery (HS). Clinical [neck disability index (NDI) and Visual Analogue Scale (VAS) score] and radiologic outcomes [range of motion (ROM) for cervical spine, adjacent segment and arthroplasty level] were evaluated at routine postoperative intervals of 1, 6, 12, 24 months. Review of other similar studies that examined the HS in multilevel cervical DDD was performed. Results : Out of 51 patients, 41 patients received 2 level hybrid surgery and 10 patients received 3 level hybrid surgery. The NDI and VAS score were significantly decreased during the follow up periods (p<0.05). The cervical ROM was recovered at 6 and 12 month postoperatively and the mean ROM of inferior adjacent segment was significantly larger than that of superior adjacent segments after surgery. The ROM of the arthoplasty level was preserved well during the follow up periods. No surgical and device related complications were observed. Conclusion : Hybrid surgery is a safe and effective alternative to fusion for the management of multilevel cervical spondylosis.

• 한국정보통신학회논문지
• /
• 제9권6호
• /
• pp.1395-1401
• /
• 2005

이동매니퓰레이터란 이동로봇과 작업로봇을 직렬로 결합하여 이동능력과 작업능력을 가지는 로봇이다. 이동매니퓰레이터의 중요한 특징중의 하나는 잉여의 자유도를 가진다는 것이다. 이를 이용하여 이동매니퓰레이터는 여러 가지 모드로 이동이 가능하고 다양한 작업을 수행할 수 있다. 이동매니퓰레이터는 고정베이스 구조의 로봇에 비해 넓은 작업공간과 특이자세 회피 및 장애물 회피에서 더 좋은 성능을 가진다. 두 대의 로봇이 협동하여 작업을 수행할 때 주어진 작업공간에서 여유자유도를 가지고 있는 이점을 이용하여 작업의 성능을 향상시킬 수 있다. 본 논문은 이동매니퓰레이터가 수행되어질 작업을 세분화 시키고 로봇의 작업 성능 지수를 사용하여 로봇이 최적자세로 작업을 수행할 수 있는 연구를 하였다. 제안된 알고리즘을 검증하기위해 이동매니퓰레이터를 제작하였고, 실험에 사용한 이동매니퓰레이터 PURL-II는 3자유도를 가지는 이동로봇과 5자유도를 가지는 작업로봇으로 구성되어 있다.

• 한국운동역학회지
• /
• 제22권1호
• /
• pp.43-53
• /
• 2012

The purpose of this study was to quantitatively examine the biomechanical variables of Fouette turns for expert and beginner ballet dancers and to determine the difference in the variables between the two groups. sixteen female ballet dancers participated in this study. They were divided into an expert group(age, $25.38{\pm}1.92$ years; height, $168.38{\pm}4.66$ cm; mass, $49.63{\pm}4.41$ kg) and a beginner group(age, $20.88{\pm}1.13$ years; height, $161.63{\pm}7.42$ cm; mass, $48.88{\pm}3.64$ kg) depending on their ballet experience. Descriptive data were expressed as mean ${\pm}$ standard deviation (SD) for all variables including the duration, displacement of the center of the body, velocity of the center of the body, angle of the body segments, angular velocity of the body segments, ground reaction force, lower extremity torque, muscle activity, body weight, age, and body mass. An independence t-test was conducted to determine how the following variables differed between the beginners and experts: duration, displacement of the center of the body, velocity of the center of the body, angle of the body segments, angular velocity of the body segments, ground reaction force, lower extremity torque, and muscle activity. All comparisons were made at the p<0.05 significance level. The results show that the experts scored high on the biomechanical variables, although all the variables were not significant. Significant differences were found in the angle of body segments, angular velocity of the body segments, lower extremity torque, and muscle activity(p<0.05). The findings of this study demonstrate that the experts have the required skill to make an improved Fouette turn. The findings may also help ballet dancers to learn and understand the Fouette turn.

• 한국운동역학회지
• /
• 제13권2호
• /
• pp.13-28
• /
• 2003

The purpose of this study was to analyze the kinematic characteristics of Ice hockey slap shot. The subjects of this study were four professional ice hockey players. The reflective markers were attached on the anatomical boundary line of body and the subjects were asked to perform the shot. Ariel Performance Analysis System was used to capture and digitize the shooting image, the data were analyzed by LabView 6i. The results were as fellows. 1. The period of the back swing phase was $0.542{\pm}0.062sec$, the down swing phase was $0.28{\pm}0.056sec$ and the total swing time was $0.825{\pm}0.017sec$ 2. The maximum linear velocity of the stick blade for x direction was shown after 7% of impact, for y, z direction were shown before 2%, 8% of Impact. 3. The maximum velocity of each segment for the left arm was $2.35{\pm}0.05m/s$ in the upper arm, $3.56{\pm}0.34m/s$ in the forearm, $4.75{\pm}0.67m/s$ in the hand. 4. The maximum velocity of each segment for the right arm was $4.67{\pm}0.43m/s$ in the upper arm, $7.22{\pm}0.69m/s$ in the forearm, $9.42{\pm}0.89m/s$ in the hand. 5. The angle of left elbow was generally flexed from the ready stance to the impact and was $82.26{\pm}3.45^{\circ}$ the moment of Impact. 6. The angle of the left shoulder was increased ut the down swing phase and was $78.74{\pm}4.78^{\circ}$ on the moment of impact. 7. The angle of the right shoulder was decreased in the down swing phase and increased before the impact. and the angle was $51.28{\pm}3.54^{\circ}$ on the moment of impact.

• Journal of Korean Neurosurgical Society
• /
• 제53권6호
• /
• pp.331-336
• /
• 2013

Objective : The offset connector can allow medial and lateral variability and facilitate intralaminar screw incorporation into the construct. The aim of this study was to compare the biomechanical characteristics of C7 intralaminar screw constructs with and without offset connector using a three dimensional finite element model of a C6-7 cervical spine segment. Methods : Finite element models representing C7 intralaminar screw constructs with and without the offset connector were developed. Range of motion (ROM) and maximum von Mises stresses in the vertebra for the two techniques were compared under pure moments in flexion, extension, lateral bending and axial rotation. Results : ROM for intralaminar screw construct with offset connector was less than the construct without the offset connector in the three principal directions. The maximum von Misses stress was observed in the C7 vertebra around the pedicle in both constructs. Maximum von Mises stress in the construct without offset connector was found to be 12-30% higher than the corresponding stresses in the construct with offset connector in the three principal directions. Conclusion : This study demonstrated that the intralaminar screw fixation with offset connector is better than the construct without offset connector in terms of biomechanical stability. Construct with the offset connector reduces the ROM of C6-7 segment more significantly compared to the construct without the offset connector and causes lower stresses around the C7 pedicle-vertebral body complex.

• Journal of Korean Neurosurgical Society
• /
• 제60권5호
• /
• pp.567-576
• /
• 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 Korean Neurosurgical Society
• /
• 제30권11호
• /
• pp.1314-1319
• /
• 2001

Objects : Because of the nonspecific nature of symptoms in tuberculous spondylitis, a delay in the diagnosis can result in progressive neurologic deficits. The authors evaluate the clinical and the radiological results of the 10 cases of surgically treated tuberculous spondylitis. Clinical materials & Methods : We retrospectively analyzed the medical records of 10 patients with tuberculous spondylitis who were treated between February 1996 and March 2000. Six patients were female, and four were male. Mean age was 43 years old, and mean follow-up period was 20.5 months. All patients were treated with 12 months of antituberculous medication postoperatively, and were followed by complete blood count, ESR, spine X-ray and MRI. Results : The lumbar spine was involved in 5 patients, the thoracic in 4, and the thoracolumbar in one. The infected vertebral bodies were 2.8 in average. The associated lesions were pulmonary tuberculosis in 3 cases, and renal tuberculosis in one. Five patients were treated by anterior debridement and fusion with bone graft using anterior instrumentation, 2 with anterior debridement and fusion with bone graft(Hong Kong procedure only), 1 with Hong Kong procedure with posterior spinal instrumentation, and 2 were managed with posterior debridement and posterior spinal instrumentation. All patients improved after operation, and the average kyphotic angle decreased postoperatively. Postoperatively, one patient had a fistula at the operative site. Conclusion : The debridement and minimal level fusion of motion segment with instrument fixation is one of surgical option for tuberculous spondyltis to preserve the spine motion segment as much as possible. Spine instability and kyphosis were prevented by anterior and posterior spinal instrumentation. But, large number of cases and longer period follow-up study in future will be needed to confirm the long term results.

• 한국콘텐츠학회논문지
• /
• 제7권4호
• /
• pp.234-240
• /
• 2007

이 연구는 철봉 몸굽혀 휘돌기 동작의 최적 모델을 구축하는 것이다. 연구 대상자는 국가대표 남자체조선수(나이 18세, 신장 153cm, 질량 48kg) 1명을 선정하였고, K대학교 체조장에 기 설치된 Spieth사의 철봉을 이용하여 실험하였다. 먼저 대상자에게 연구의 목적과 주의 사항을 주지시키고 사전 서면동의를 받은 후 실험을 실시하였다. 인체를 2분절로 모형화한 몸 굽혀 휘돌기 동작의 영상분석을 위하여 Qualisys사의 카메라(MCU-240) 6대와 소프트웨어인 QTM(Qualisys Track Mannager)을 사용하였다. 이 동작을 이중진자(HAT/total leg)로 모형화하고 라그랑지 운동방정식의 파라메터에 실험에서 획득한 수치를 입력하여 시뮬레이션하였다. 데이터 처리와 모델(미분 연립 방정식)의 해는 Mathematicas5.0으로 프로그래밍하여 구하였다. 분석변인에 대한 모델치와 실험치의 비교 결과는 첫째, 철봉의 최대변위는 모델치(약 0.18 m)가 실험치(약 0.16 m)보다 약 0.02m 더 크게 나타났다. 둘째, 분절1(HAT)의 각변위 패턴은 모두 증가곡선을 보였으나 변곡점의 차이가 나타났다. 셋째, 분절2(total leg)의 각변위 패턴은 전반적으로 유사하게 나타났으나 최대 각은 약 $4^{\circ}$ 차이를 보였다. 결론적으로 실험치와 일치하는 최적모델을 도출하지는 못하였지만 라그랑지 모델을 통한 시뮬레이션의 가능성을 제시하였다. 향후 제한된 2분절 모형을 3, 4분절 모델로 확장하고 생체물성(근골격계)을 정확하게 표현하는 물리적 도구를 개발하는 연구와 인체시스템을 근골격계와 근신경계을 통합한 모델구축이 이루어져야 하겠다.

• Composites Research
• /
• 제34권3호
• /
• pp.186-191
• /
• 2021

요추에 퇴행이 발생하였을 때 이를 치료하기 위해 요추 유합술이 시행된다. 유합술은 척추체 사이의 추간판을 제거하고 뼈 그래프트 등을 삽입하여 굳혀 하나 이상의 분절을 완전히 고정시켜 척추의 안정성을 복원한다. 둘 이상의 척추체가 단단히 유합될 수 있게끔 척추체를 고정하는 수단으로 척추경 나사못과 연결봉이 환자의 체내에 삽입된다. 본 연구에서는 중증 요추 퇴행성 질환의 치료에 쓰이는 척추 유합술에서 사용하는 척추경 나사못 구조물이 적용된 총 7개의 환자 맞춤형 요추 유한 요소 모델을 생성하였다. 생성한 모델에 각각 티타늄과 CFR-PEEK로 구성된 연결봉을 구성하였다. 척추의 4가지 대표적 거동에 대해 유한요소해석과 통계적 분석을 진행하여 연결봉의 재질이 척추 상태에 미치는 의공학적 영향을 조사하였다. 인접 분절의 추간판 내 압력과 각 분절의 관절 구동 범위가 의공학적 영향을 확인하기 위한 지표로 사용되었다. 연결봉에 CFR-PEEK를 사용한 경우 Ti 연결봉에 비해 인접 분절의 추간판 내 압력은 감소하였고 각 분절의 관절 구동 범위는 증가하였다. 그러나 모든 하중조건에서 통계학적으로 유의미한 경향성 차이는 관찰되지 않았다.

• 한국방사선학회논문지
• /
• 제16권6호
• /
• pp.787-797
• /
• 2022

본 연구는 온열·마사지 자극이 가능한 기계식 침대 적용을 통해 척추를 수직으로 자극하여, 파킨슨병의 통증 감소 및 증상 완화를 확인하고자 하였다. 이를 위해 파킨슨병 환자를 대상으로 의료용 조합자극 침대를 사용함에 따른 척추의 분절운동을 확인한 후 시각아날로그척도, 요통 기능 장애, 보행 능력, 나선형 그리기 검사를 실시하고 해당 변수 간의 관계를 파악하였다. 10일간의 시각아날로그척도, 요통 기능 장애 평가에서 침대 사용 후 평균이 감소하는 경향을 확인하였다. 보행 능력은 이동 시간의 감소와 이동 거리의 증가를 관찰하였다. 나선형 그리기 검사에서 침대 사용 후 검사 시간의 평균이 전보다 유의하게 낮았다. 그 결과, 기계식 온열 및 마사지로 척추 분절운동이 발생함에 따른 파킨슨병 환자의 회복 및 통증 완화를 위한 보조적인 방법으로 사용할 수 있는 가능성을 제시하였다. 그러나 본 연구는 예비적 연구로 피험자수가 적어 향후 피험자수와 상태를 세부적으로 고려한 추가적 연구가 필요하다.