• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.187-188
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• 2006

A 3-D finite element model of human thoracolumbar spine (T12-L2) was reconstructed from CT images. Various anterior and posterior instrumentation techniques were performed with long cage after corpectomy. Six loading cases were applied up to 10 Nm, espectively. The rotations of T12 with respect to L2 were measured and the stiffnesses were calculated as the applied forces divided by the segmental rotations. The posterior fixation technique increased the stiffness of the spine the most. The addition of anterior rod from 1 to 2 increased the stiffness significantly without posterior fixation, but no effect was found with posterior fixation. We found that different fixation techniques changed the stiffness of the spine.

• Journal of Korean Neurosurgical Society
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• 제29권2호
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• pp.203-209
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• 2000

Objective : The authors retrospectively analysed the factors affecting the favorable outcomes in the treatment of the Failed Back Surgery Syndrome(FBSS) or six years. Method : From March 1991 to December 1996, seventy-five patients were diagnosed as FBSS and its incidence was 3.4% of admitted patients with back pain in our department. We analysed the demographic data, etiologies, clinical menifestations, outcomes according to methods of operation, numbers of previous surgery, and time intervals between initial operation and final operation. Result : The most common etiology and previous surgical method of FBSS were insufficient surgery(54.7%) and partial laminectomy(53.3%). Patients were managed as followings ; Total laminectomy and spinal fusion with instrument in 41 cases(54.7%), total laminectomy without fusion in 23 cases(30.7%), and only partial laminectomy in 11 cases(14.7%). The overall treatment outcome was satisfactory in 48 cases(64%). Satisfactory results were observed in those patients who were treated by spinal fusion after complete laminectomy(34 cases), who had underwent only one operation previously(45 cases), and when the time interval between the initial operation and reoperation is shorter than 12 months(43 cases). Conclusion : The treatment outcome in FBSS was favorable in cases of the complete total laminectomy and spinal fusion with instrument, only one previous back surgery, and short time interval between initial and final operations.

• International Journal of Control, Automation, and Systems
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• 제4권1호
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• pp.30-41
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• 2006

The goal of this work is to develop and test a robot-assisted surgery system for spinal fusion. The system is composed of a robot, a surgical planning system, and a navigation system. It plays the role of assisting surgeons for inserting a pedicle screw in the spinal fusion procedure. Compared to conventional methods for spinal fusion, the proposed surgical procedure ensures minimum invasion and better accuracy by using robot and image information. The robot plays the role of positioning and guiding needles, drills, and other surgical instruments or conducts automatic boring and screwing. Pre-operative CT images intra-operative fluoroscopic images are integrated to provide the surgeon with information for surgical planning. Some experiments employing the developed robotic surgery system are conducted. The experimental results confirm that the system is not only able to guide the surgical tools by accurately pointing and orienting the specified location, but also successfully compensate the movement of the patient due to respiration.

• Journal of Korean Neurosurgical Society
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• 제41권3호
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• pp.157-160
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• 2007

Objective : The purpose of this study was to evaluate the efficacy and safety of the surgical treatment for lumbar spinal stenosis in elderly patients. Methods : The authors reviewed the medical records of 49 patients older than 65 years of age with lumbar spinal stenosis who underwent surgical treatment from January 2002 to December 2004 in our institute. Results : Average age of patients was 70 years old [32 women, 17 men]. Twenty-four patients had chronic medical disorders. All patients were operated under the general anesthesia of these, 29 patients underwent decompressive laminectomy and decompressive laminectomy with instrumentation and fusion in 20 patients. The mean operation time was 193.5 minutes, mean estimated blood loss was 378cc and mean postoperative hospital stay length was 15.3 days. The mean follow-up duration was 11.9 months. The evaluation of outcome was assessed by Macnab classification. At first month after operation, the outcome showed excellent in 7 [14.3%]. good in 35 [71.4%], fair in 5 [10.2%], and poor in 2 [4.1%]. And at 6 months after operation, 17 patients were lost in follow-up, the outcome showed excellent in 4 [12.5%], good in 25 [78.1%], fair in 3 [9.4%], and no poor cases. There was no significant difference between outcome of laminectomy alone and that of laminectomy with fusion. Six patients [12.2%] experienced postoperative complications which included wound infection [3], nerve root injury [1], disc herniation [1], and reoperation due to insufficient decompression [1]. There were no deaths related to operation. Conclusion : We conclude that the surgical treatment for lumbar spinal stenosis in elderly patients can provide good results with acceptable morbidity when carefully selected. In addition, decision on lumbar spinal fusion should not be against solely on advanced age.

• Asian Spine Journal
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• 제12권6호
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• pp.1060-1068
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• 2018

Study Design: Retrospective study. Purpose: Lumbar intervertebral disc degeneration is an important cause of low back pain. Overview of Literature: Spinal fusion is often reported to have a good course for adolescent idiopathic scoliosis (AIS). However, many studies have reported that adjacent segment degeneration is accelerated after lumbar spinal fusion. Radiography is a simple method used to evaluate the orientation of the vertebral column. magnetic resonance imaging (MRI) is the method most often used to specifically evaluate intervertebral disc degeneration. The Pfirrmann classification is a well-known method used to evaluate degenerative lumbar disease. After spinal fusion, an increase in stress, excess mobility, increased intra-disc pressure, and posterior displacement of the axis of motion have been observed in the adjacent segments. Methods: we retrospectively secured and analyzed the data of 15 patients (four boys and 11 girls) with AIS who underwent a spinal fusion surgery. We studied the full-length view of the spine (anterior-posterior and lateral) from the X-ray and MRI obtained from all patients before surgery. Postoperatively, another full-length spine X-ray and lumbosacral MRI were obtained from all participants. Then, pelvic tilt, sacral slope, curve correction, and fused and free segments before and after surgery were calculated based on X-ray studies. MRI images were used to estimate the degree to which intervertebral discs were degenerated using Pfirrmann grading system. Pfirrmann grade before and after surgery were compared with Wilcoxon signed rank test. While analyzing the contribution of potential risk factors for the post-spinal fusion Pfirrmann grade of disc degeneration, we used generalized linear models with robust standard error estimates to account for intraclass correlation that may have been present between discs of the same patient. Results: The mean age of the participant was 14 years, and the mean curvature before and after surgery were 67.8 and 23.8, respectively (p<0.05). During the median follow-up of 5 years, the mean degree of the disc degeneration significantly increased in all patients after surgery (p<0.05) with a Pfirrmann grade of 1 and 2.8 in the L2-L3 before and after surgery, respectively. The corresponding figures at L3-L4, L4-L5, and L5-S1 levels were 1.28 and 2.43, 1.07 and 2.35, and 1 and 2.33, respectively. The lower was the number of free discs below the fusion level, the higher was the Pfirrmann grade of degeneration (p<0.001). Conversely, the higher was the number of the discs fused together, the higher was the Pfirrmann grade. Conclusions: we observed that the disc degeneration aggravated after spinal fusion for scoliosis. While the degree of degeneration as measured by Pfirrmann grade was directly correlated by the number of fused segments, it was negatively correlated with the number of discs that remained free below the lowermost level of the fusion.

• Journal of Korean Neurosurgical Society
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• 제37권5호
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• pp.364-369
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• 2005

Objective: Spinal instrumentation without fusion often fails due to biological failure of intervertebral joints (spontaneous fusion, degeneration, etc). The purpose of this study is to investigate the influence of fixation rigidity on viability of intervertebral joints. Methods: Twenty pigs in growing period were subjected to posterior segmental fixation. Twelve were fixed with a rigid fixation system(RF) while eight were fixed with a flexible unconstrained implant(FF). At the time of the surgery, a scoliosis was created to monitor fixation adequacy. The pigs were subjected to periodic radiological examinations and 12pigs (six in RF, six in FF) were euthanized at 12-18months postoperatively for analysis. Results: The initial scoliotic curve was reduced from $31{\pm}5^{\circ}$ to $27{\pm}8^{\circ}$ in RF group (p=0.37) and from $19{\pm}4^{\circ}$ to $17{\pm}5^{\circ}$ in FF group (p=0.21). Although severe disc degeneration and spontaneous fusion of facet joints were observed in RF group, disc heights of FF group were well maintained without major signs of degeneration. Conclusion: The viability of the intervertebral joints depends on motion spinal fixation. Systems allowing intervertebral micromotion may preserve the viability of intervertebral discs and the facet joint articular cartilages while maintaining a reasonably stable fixation.

• Journal of Korean Neurosurgical Society
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• 제60권2호
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• pp.174-180
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• 2017

Objective : Proximal junctional kyphosis (PJK) is radiologic finding, and is defined as kyphosis of >$10^{\circ}$ at the proximal end of a construct. The aim of this study is to identify factors associated with PJK after segmental spinal instrumented fusion in adults with spinal deformity with a minimum follow-up of 2 years. Methods : A total of 49 cases of adult spinal deformity treated by segmental spinal instrumented fusion at two university hospitals from 2004 to 2011 were enrolled in this study. All enrolled cases included at least 4 or more levels from L5 or the sacral level. The patients were divided into two groups based on the presence of PJK during follow-up, and these two groups were compared to identify factors related to PJK. Results : PJK was observed in 16 of the 49 cases. Age, sex and mean follow-up duration were not statistically different between two groups. However, mean bone marrow density (BMD) and mean back muscle volume at the T10 to L2 level was significantly lower in the PJK group. Preoperatively, the distance between the C7 plumb line and uppermost instrumented vertebra (UIV) were no different in the two groups, but at final follow-up a significant intergroup difference was observed. Interestingly, spinal instrumentation factors, such as, receipt of a revision operation, the use of a cross-link, and screw fracture were no different in the two groups at final follow-up. Conclusion : Preoperative BMD, sagittal imbalance at UIV, and thoracolumbar muscle volume were found to be strongly associated with the presence of PJK.

• Journal of Korean Neurosurgical Society
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• 제38권3호
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• pp.206-210
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• 2005

Objective : Our aim is to evaluate the early changes of biologic markers such as white blood cell[WBC] count, erythrocyte sedimentation rate[ESR] and C-reactive protein[CRP] in early diagnosis of postoperative infection and to differentiate infection from inflammatory reaction in lumbar spine surgery. Methods : We reviewed 330patients who had undergone spinal operations between May 1999 and October 2001. For this study, the patients were classified into two groups, which include a group that underwent spinal decompressive surgery without instrumentation[SD], and the other group that underwent fusion surgery with spinal instrumentation[SI]. And each group was also subdivided into two groups respectively, one with infection and the other without infection. We retrospectively analyzed the WBC count, ESR and CRP preoperatively and postoperatively, according to their operation type and postoperative infection history. Results : Inflammatory indices were physiologically affected by instrumentation itself. But ESR and CRP elevations were more prolonged and sustained under infection. In SD patients without infection, ESR and CRP were stabilized 5 days after surgery. In SI patients without infection, CRP was stabilized about 7days after surgery, but ESR showed sustained and variously elevated. In both SD and SI groups, the stabilization of CRP was the most reliable behavior of surgery without infection. Conclusion : C-reactive protein is most sensitive parameter for postoperative spine infection. The knowledge of the inflammatory indices and their relatively uniform patterns with or without infection offers surgeons the ability to infer the state of surgical wound.

• Journal of Trauma and Injury
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• 제30권4호
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• pp.212-215
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• 2017

The choice of the most appropriate treatment for thoracolumbar or lumbar spine burst fracture remains controversial from conservative treatment to fusion through a posterior or anterior approach. There are many cases where ligamentotaxis is used to reduce the burst fracture. However, indirect reduction using ligamentotaxis is often limited in the magnitude of the reduction that it can achieve. In our patient with severe burst fracture, we were able to restore an almost normal level of vertebral height and secure spinal canal widening by using only ligamentotaxis by posterior instrumentation. Before the operation, the patient had more than 95% encroachment of the spinal canal. This was reduced to less than 10% after treatment.

• Journal of Yeungnam Medical Science
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• 제13권2호
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• pp.234-242
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• 1996

영남대학교 의과대학 부속병원 신경외과에서 1994년 l월부터 1994년 12월까지 1년간 흉요추접합부 파열골절로 입원한 환자중 전측방경유법으로 10례를 수술로 치료경험 하였던 바, 척추골절이 척수원추 상부이면서 전방의 골편에 의해 척수신경이 압박되고 있는 불안정 파열골절시는 전방도달술에 의한 늑골 골융합 및 Kaneda기기내고정술로 좋은 결과를 기대할 수 있겠고, 척수 후주의 심한 손상이나 또는 3 column을 전체가 손상된 불안정 파열골절의 경우에는 후방접근법이나 후측방접근법으로 신경감압 및 내고정술 시행하는 것이 좋은 치료법이라 할 수 있겠다.