• 대한기계학회논문집A
• /
• 제36권1호
• /
• pp.29-35
• /
• 2012

척추관 협착증은 감압술과 융합술 그리고 인공추간판 치환술 등이 있으며, 2000년대 중반부터는 인공추간판 치환술이 널리 시술되고 있다. 인공추간판의 연구는 추간판의 자유도 및 추체의 굴곡-신전, 측굴전, 축회전에 대한 해석이 핵심기술이지만, 시술 후 수년이 경과하여 발생하는 피로파손이 새롭게 큰 문제점으로 대두되고 있다. 따라서 인공추간판 연구는 슬라이딩 코어의 피로특성 및 내구성 향상에 집중되어야 한다. 본 연구에서는 세계적으로 가장 많이 사용되는 인공추간판 제품(SB Charit$\acute{e}$ III)을 기초로 유한요소모델을 제작하고, 슬라이딩 코어의 곡률반경과 마찰계수의 변화가 von-Mises 응력과 접촉압력에 미치는 영향을 평가하였다. 이와 같은 결과를 바탕으로 새로운 인공추간판 모델들 (Model-I, -II, -III)을 제안하고 일정수명 후 발생할 수 있는 슬라이딩 코어의 피로파손 거동에 대해 SB Charit$\acute{e}$ III의 결과와 비교 평가하였다.

• 한국방사선학회논문지
• /
• 제4권2호
• /
• pp.5-11
• /
• 2010

골다공성 폐경 후 여성에서 단일 에너지를 이용한 정량적 전산화 단층촬영술로 골무기질 함량을 측정하여 건강한 여성과 비교분석하였다. 1군은 건강한 폐경전 여성, 2군은 폐경후 건강한 여성, 3군은 골다공증성 폐경후 여성으로 나눈 환자들에게 QCT를 이용하여 측정된 골밀도가 각 군간에 차이가 있는지 알아보고 각 군내 혹은 다른 군간에 척추 부위에 따른 영향이 있는지를 부위별로 비교분석하였고, 골무기질 함량의 측정은 타원형의 region of interest를 이용하여 T12-L4에서 척추의 해면질 부위에서 측정하였다. 연령이 증가함에 따라 골밀도는 감소하였고 건강한 군과 비교하여 골다공증 환자군에서 유의하게 낮은 골밀도를 관할 할 수 있었다. 건강한 폐경전 여성군을 제외한 모든군에서 T12에서 L4로 갈수록 골밀도가 감소하였다. 통계학적으로 모든 척추체에서 골밀도로 1, 2, 3군간 서로를 구분할 수 있으나 2군과 3군은 골밀도로는 서로간의 구분할 수 없는 것으로 분석되었다.

• 대한핵의학회지
• /
• 제36권4호
• /
• pp.255-260
• /
• 2002

목적: SAPHO 증후군은 전흉벽의 골관절에 주로 위치하는 혈청학적 검사상 음성을 보이면서 다양한 피부증상을 동반하는 골관절 질환으로 질병의 특성에 대한 폭넓은 이해를 통하여 조기진단을 함으로써 불필요한 수술이나 장기간의 비효율적인 항생제 치료를 피하는 것이 임상적으로 중요점이라 할 수가 있겠다. 이에 저자들은 SAPHO 증후군으로 진단받은 환자에서 골신티그라피의 소견의 특징을 알아보고 유용성을 알아보고자 하였다. 대상 및 방법: 다발성 관절통과 반복적으로 재발되는 피부증상이 있어 임상적으로 SAPHO 증후군으로 진단 받은 5명의 환자(모두 남자, $22.8{\pm}4.75$세)를 대상으로 하였다. 모든 환자에서 저에너지 고해상도 조준기가 장착된 이중헤드 감마카메라(ECAM, Siemens, Germany)를 이용하여 전신영상을 얻었고, 2명의 환자에서는 척추 관절의 이상 유무를 확인하기 위하여 SPECT 영상을 얻었다. 골신티그라피상 섭취증가를 보이는 관절을 알아보고 호발빈도와 단순 X선과 관절 침범 유무를 진단하는 성능을 비교하였다. 결과: 골신티그라피상 모든 환자에서 이상소견을 보인 관절은 흉쇄골 관절, 천장골 관절, 수부의 소관절이었다. 흉쇄골 관절이상은 양측성이 3/5 (60%)이고 일측성이 2/5 (40%)로 관찰되었다. 천장골 관절에서는 양측성이 4/5 (80%) 이고 일측성이 1/5 (20%)로 관찰되었다. 척추 관절의 이상은 4/5 (80%)에서 관찰되었는데 이 가운데 요추 이상은 4명 모두에서 볼수가 있었고 흉추의 이상은 3명, 경추의 이상은 1명에서 보여 척추에서는 요추의 침범이 가장 많았다. 척추골 SPECT는 2명에서 시행되었는데 추체나 척추경 보다는 후관절에 이상을 초래함을 평면영상에 비하여 보다 상세히 알 수가 있었다. 결론: SAPHO 증후군은 피부증상과 함께 다양한 골관절을 침범하는 질환으로 골신티그라피를 시행함으로써 관절의 이상을 조기에 진단하여 불필요한 수술이나 장기간의 비효율적인 항생제 치료를 피하는데 도움이 될 것으로 사료된다.

• Journal of Korean Neurosurgical Society
• /
• 제60권4호
• /
• pp.448-455
• /
• 2017

Objective : To investigate the magnetic resonance imaging (MRI) findings and the patterns of postoperative spinal infection according to the passage of time. Methods : Institutional review board approval was obtained, and informed consent was not obtained for the retrospective review of patients' medical records. A total of 43 patients (27 men and 16 women; mean age, 64) diagnosed with postoperative spinal infection were included in this study. We retrospectively reviewed the MRI findings and the medical records and categorized the infection sites based on MRI, i.e., anterior, posterior, and both parts. The duration of the clinical onset from surgery was divided, i.e., acute (${\leq}2weeks$), subacute (2-4 weeks), and late (>4 weeks). Results : Postoperative spinal infection was involved in the posterior part in 31 (72%), anterior part in two (4.7%), and both parts in 10 patients (23.3%). Abscess or phlegmon in the back muscles and laminectomy site were the most common MRI findings. The number of patients with acute, subacute, and late clinical onset were 35, two, and six, respectively (mean, 33.4 days; range, 1-730 days). The mean duration of the clinical onset was 12 days in the posterior part, 15.2 days in both parts, and 456.5 days in the anterior part. Conclusion : Postoperative spinal infection usually occurred within four weeks in the posterior part and over time the infection was considered to spread into the anterior part. For the evaluation of postoperative spinal infection, the posterior surgical field was more important than the vertebral body or the disc space on MRI.

• Journal of Korean Neurosurgical Society
• /
• 제60권5호
• /
• pp.577-583
• /
• 2017

Objective : Laminoplasty is an effective surgical method for treating cervical degenerative disease. However, postoperative complications such as kyphosis, restriction of neck motion, and instability are often reported. Despite sufficient preoperative lordosis, this procedure often aggravates the lordotic curve of the cervical spine and straightens cervical alignment. Hence, it is important to examine preoperative risk factors associated with postoperative kyphotic alignment changes. Our study aimed to investigate preoperative radiologic parameters associated with kyphotic deformity post laminoplasty. Methods : We retrospectively reviewed the medical records of 49 patients who underwent open door laminoplasty for cervical spondylotic myelopathy (CSM) or ossification of the posterior longitudinal ligament (OPLL) at Pusan National University Yangsan Hospital between January 2011 and December 2015. Inclusion criteria were as follows : 1) preoperative diagnosis of OPLL or CSM, 2) no previous history of cervical spinal surgery, cervical trauma, tumor, or infection, 3) minimum of one-year follow-up post laminoplasty with proper radiologic examinations performed in outpatient clinics, and 4) cases showing C7 and T1 vertebral body in the preoperative cervical sagittal plane. The radiologic parameters examined included C2-C7 Cobb angles, T1 slope, C2-C7 sagittal vertical axis (SVA), range of motion (ROM) from C2-C7, segmental instability, and T2 signal change observed on magnetic resonance imaging (MRI). Clinical factors examined included preoperative modified Japanese Orthopedic Association scores, disease classification, duration of symptoms, and the range of operation levels. Results : Mean preoperative sagittal alignment was $13.01^{\circ}$ lordotic; $6.94^{\circ}$ lordotic postoperatively. Percentage of postoperative kyphosis was 80%. Patients were subdivided into two groups according to postoperative Cobb angle change; a control group (n=22) and kyphotic group (n=27). The kyphotic group consisted of patients with more than $5^{\circ}$ kyphotic angle change postoperatively. There were no differences in age, sex, C2-C7 Cobb angle, T1 slope, C2-C7 SVA, ROM from C2-C7, segmental instability, or T2 signal change. Multiple regression analysis revealed T1 slope had a strong relationship with postoperative cervical kyphosis. Likewise, correlation analysis revealed there was a statistical significance between T1 slope and postoperative Cobb angle change (p=0.035), and that there was a statistically significant relationship between T1 slope and C2-C7 SVA (p=0.001). Patients with higher preoperative T1 slope demonstrated loss of lordotic curvature postoperatively. Conclusion : Laminoplasty has a high probability of aggravating sagittal balance of the cervical spine. T1 slope is a good predictor of postoperative kyphotic changes of the cervical spine. Similarly, T1 slope is strongly correlated with C2-C7 SVA.

• Journal of Korean Neurosurgical Society
• /
• 제62권4호
• /
• pp.376-381
• /
• 2019

Objective : To define optimal method that calculate the safe direction of cervical pedicle screw placement using computed tomography (CT) image based three dimensional (3D) cortical shell model of human cervical spine. Methods : Cortical shell model of cervical spine from C3 to C6 was made after segmentation of in vivo CT image data of 44 volunteers. Three dimensional Cartesian coordinate of all points constituting surface of whole vertebra, bilateral pedicle and posterior wall were acquired. The ideal trajectory of pedicle screw insertion was defined as viewing direction at which the inner area of pedicle become largest when we see through the biconcave tubular pedicle. The ideal trajectory of 352 pedicles (eight pedicles for each of 44 subjects) were calculated using custom made program and were changed from global coordinate to local coordinate according to the three dimensional position of posterior wall of each vertebral body. The transverse and sagittal angle of trajectory were defined as the angle between ideal trajectory line and perpendicular line of posterior wall in the horizontal and sagittal plane. The averages and standard deviations of all measurements were calculated. Results : The average transverse angles were $50.60^{\circ}{\pm}6.22^{\circ}$ at C3, $51.42^{\circ}{\pm}7.44^{\circ}$ at C4, $47.79^{\circ}{\pm}7.61^{\circ}$ at C5, and $41.24^{\circ}{\pm}7.76^{\circ}$ at C6. The transverse angle becomes more steep from C3 to C6. The mean sagittal angles were $9.72^{\circ}{\pm}6.73^{\circ}$ downward at C3, $5.09^{\circ}{\pm}6.39^{\circ}$ downward at C4, $0.08^{\circ}{\pm}6.06^{\circ}$ downward at C5, and $1.67^{\circ}{\pm}6.06^{\circ}$ upward at C6. The sagittal angle changes from caudad to cephalad from C3 to C6. Conclusion : The absolute values of transverse and sagittal angle in our study were not same but the trend of changes were similar to previous studies. Because we know 3D address of all points constituting cortical shell of cervical vertebrae. we can easily reconstruct 3D model and manage it freely using computer program. More creative measurement of morphological characteristics could be carried out than direct inspection of raw bone. Furthermore this concept of measurement could be used for the computing program of automated robotic screw insertion.

• Journal of Korean Neurosurgical Society
• /
• 제64권4호
• /
• pp.575-584
• /
• 2021

Objective : Cervical expansive laminoplasty is an effective surgical method to address multilevel cervical spinal stenosis. During surgery, the spinous processes of C2 and C7 are usually preserved to keep the insertion points of the cervical musculature and nuchal ligament intact. In this regard, dome-like laminectomy (undercutting of C7 lamina) instead of laminoplasty is performed on C7 in selected cases. However, resection of the lamina can weaken the C7 lamina, and stress fractures may occur, but this complication has not been characterized in the literature. The objective of the present study was to investigate the incidence and risk factors for C7 laminar fracture after C7 dome-like laminectomy and its impact on clinical and radiological outcomes. Methods : Patients who underwent cervical open-door laminoplasty combined with C7 dome-like laminectomy (n=123) were classified according to the presence of C7 laminar fracture. Clinical parameters (neck/arm pain score and neck disability index) and radiologic parameters (C2-7 angle, C2-7 sagittal vertical axis, and C7-T1 angle) were compared between the groups preoperatively and at postoperatively at 3, 6, 12, and 24 months. Risk factors for complications were evaluated, and a formula estimating C7 fracture risk was suggested. Results : C7 lamina fracture occurred in 32/123 (26%) patients and occurred at the bilateral isthmus in 29 patients and at the spinolaminar junction in three patients. All fractures appeared on X-ray within 3 months postoperatively, but patients did not present any neurological deterioration. The fracture spontaneously healed in 27/32 (84%) patients at 1 year and in 29/32 (91%) at 2 years. During follow-up, clinical outcomes were not significantly different between the groups. However, patients with C7 fractures showed a more lordotic C2-7 angle and kyphotic C7-T1 angle than patients without C7 fractures. C7 fracture was significantly associated with the extent of bone removal. By incorporating significant factors, the probability of C7 laminar fracture could be assessed with the formula 'Risk score = 1.08 × depth (%) + 1.03 × length (%, of the posterior height of C7 vertebral body)', and a cut-off value of 167.9% demonstrated a sensitivity of 90.3% and a specificity of 65.1% (area under the curve, 0.81). Conclusion : C7 laminar fracture can occur after C7 dome-like laminectomy when a substantial amount of lamina is resected. Although C7 fractures may not cause deleterious clinical outcomes, they can lead to an unharmonized cervical curvature. The chance of C7 fracture should be discussed in the shared decision-making process.

• 한방재활의학과학회지
• /
• 제32권1호
• /
• pp.51-62
• /
• 2022

Objectives Objective of this study is to investigate the role of paraspinal muscles by examining the correlation between slip percentage (SP) of spondylolisthesis and fatty infiltration of lumbar paraspinal muscle. Methods Retrospective analysis was performed on 45 patients diagnosed with spondylolisthesis based on medical records. Using T2-weighted axial magnetic resonance imaging, cross-sectional areas (CSAs) of psoas major (PM), multifidus (MU) and erector spinae (ES) were calculated and divided by CSA of lower level vertebral body (VB). SP was measured using sagittal T2-weighted images. Correlation of SP with muscle relative cross-sectional area (RCSA) and muscle fatty infiltration by Goutallier classification was respectively analyzed using Spearman correlation. Statistic assessment conducted by Wilcoxon signed rank test and paired t-test using program GraphPad prism 5 (GraphPad Software, Inc., San Diego, CA, USA). Results Spondylolisthesis forward slip percentage by Taillard's method was negatively associated with both side MU RCSAs. No significant correlation was found between PM RCSA, ES RCSA and SP. Forward slippage was significantly correlated with fatty infiltration of lumbar paraspinal muscle measured by Goutallier classification. Conclusions This study is to understand the role of paraspinal muscle affecting spinal instability by investigating correlation between statistical deviation of lumbar muscle characters (RCSA, fatty infiltration of lumbar muscle) and SP. We found that spondylolisthesis SP is positively related to fatty infiltration of lumbar paraspinal muscle. and is negatively associated with both side MU RCSAs.

• Korean Journal of Radiology
• /
• 제22권11호
• /
• pp.1850-1857
• /
• 2021

Objective: The purpose of this study was to assess whether a deep learning (DL) algorithm could enable simultaneous noise reduction and edge sharpening in low-dose lumbar spine CT. Materials and Methods: This retrospective study included 52 patients (26 male and 26 female; median age, 60.5 years) who had undergone CT-guided lumbar bone biopsy between October 2015 and April 2020. Initial 100-mAs survey images and 50-mAs intraprocedural images were reconstructed by filtered back projection. Denoising was performed using a vendor-agnostic DL model (ClariCT.AI^TM, ClariPI) for the 50-mAS images, and the 50-mAs, denoised 50-mAs, and 100-mAs CT images were compared. Noise, signal-to-noise ratio (SNR), and edge rise distance (ERD) for image sharpness were measured. The data were summarized as the mean ± standard deviation for these parameters. Two musculoskeletal radiologists assessed the visibility of the normal anatomical structures. Results: Noise was lower in the denoised 50-mAs images (36.38 ± 7.03 Hounsfield unit [HU]) than the 50-mAs (93.33 ± 25.36 HU) and 100-mAs (63.33 ± 16.09 HU) images (p < 0.001). The SNRs for the images in descending order were as follows: denoised 50-mAs (1.46 ± 0.54), 100-mAs (0.99 ± 0.34), and 50-mAs (0.58 ± 0.18) images (p < 0.001). The denoised 50-mAs images had better edge sharpness than the 100-mAs images at the vertebral body (ERD; 0.94 ± 0.2 mm vs. 1.05 ± 0.24 mm, p = 0.036) and the psoas (ERD; 0.42 ± 0.09 mm vs. 0.50 ± 0.12 mm, p = 0.002). The denoised 50-mAs images significantly improved the visualization of the normal anatomical structures (p < 0.001). Conclusion: DL-based reconstruction may enable simultaneous noise reduction and improvement in image quality with the preservation of edge sharpness on low-dose lumbar spine CT. Investigations on further radiation dose reduction and the clinical applicability of this technique are warranted.

• 대한영상의학회지
• /
• 제82권6호
• /
• pp.1413-1440
• /
• 2021

MRI에서 추간판의 이상 신호와 위, 아래 척추체 종판의 파괴, 종판 주변의 골수부종 등은 감염성 척추염의 전형적인 소견으로 여겨지나 퇴행성 척추질환, acute Schmorl's node, 척추관절병증, synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO)/chronic recurrent multifocal osteomyelitis, 척추신경관절병증, calcium pyrophosphate dehydrate 결절침착질환 등 다양한 비감염성 척추질환에서도 나타날 수 있다. MRI에서 이러한 비감염성 척추질환과 감별되는 감염성 척추염의 영상 소견은 추간판의 고신호와 농양, 척추 연부조직의의 농양, 그리고 T1 강조영상에서 저신호로 보이는 종판의 경계가 불명확해지는 점 등이다. 그러나 이러한 감별점이 항상 적용되는 것은 아니며 감염성, 비감염성 질환의 영상 소견에 유사점이 많기 때문에 정확한 진단을 위해서는 감염성 척추염뿐만 아니라 감염과 감별해야 하는 다양한 질환의 병태생리와 연관된 영상학적 특징을 아는 것이 중요하다.