Application of three-dimensional models constructed using virtual simulation technique in the vertebral metastatic tumor

中国组织工程研究第 18 卷第 48 期 2014 11 26 出版 Chinese Journal of Tissue Engineering Research November 26, 2014 Vol.18, No.48 Application of three-dimensional models constructed using virtual simulation technique in the vertebral metastatic tumor Liu Deng-jun 1, He Xiao-bing 1, Wang Ming-gui 1, Li Zheng-yan 1, Li Qi 2, Lin Li-jun 2 1 Department of Orthopedics, Chongqing Fuling Central Hospital, Chongqing 408000, China; 2 Department of Orthopedics, Zhujiang Hospital of Southern Medical University, Guangzhou 510282, Guangdong Province, China Abstract BACKGROUND: Vertebral metastatic tumor often damages vertebral body and the appendix, and causes severe pain in patients and high incidence of complications, such as paraplegia and spinal kyphosis. The principle of metastatic tumor treatment is early diagnosis, complete surgical resection, and postoperative chemotherapy. Imaging techniques such as CT can detect spinal metastases and accurately position the tumor before surgery. Currently visualized simulation and virtual reality techniques have been increasingly used in the field of orthopedics. OBJECTIVE: To find an anterior-posterior approach for the treatment of vertebral metastases using visual reality technique. METHODS: Based on the 64-layer spiral CT two-dimensional images of lumbar vertebra, we reconstructed the structure of normal vertebrae, affected vertebrae, abdominal aorta and bilateral kidney three-dimensionally using Mimics software. Then anterior debridement, titanium bone cement supporting, and posterior pedicle screw fixation were performed on three-dimensional models. RESULTS AND CONCLUSION: Three-dimensionally reconstructed models were clearly visible in Dicom format, and can reproduce the structure of affected vertebrae and adjacent organs. The virtual stimulation operation provided clarity with strong relief perception. Virtual simulation surgery accurately visualize three-dimensional structure of malignant tumor and adjacent structure, position the lesion site, and reconstruct spinal sequence via the posterior approach. This method provides an objective evidence for individualized treatment programs. Liu Deng-jun, Attending physician, Department of Orthopedics, Chongqing Fuling Central Hospital, Chongqing 408000, China Corresponding author: Liu Deng-jun, Department of Orthopedics, Chongqing Fuling Central Hospital, Chongqing 408000, China doi:10.3969/j.issn.2095-4344. 2014.48.024 [http://www.crter.org] Accepted: 2014-09-09 Subject headings: tissue engineering; lumbar vertebrae; malignant tumor; vertebral column Liu DJ, He XB, Wang MG, Li ZY, Li Q, Lin LJ. Proliferation ability of bone mesenchymal stem cells in corticosteroid-induced osteonecrosis of femoral head. Zhongguo Zuzhi Gongcheng Yanjiu. 2014;18(48):7844-7848. INTRODUCTION Vertebral metastases often destruct the vertebral body and attachments, and patients with vertebral metastases suffer from severe pain, moreover, they are often regarded as having complicated disease with a high risk of recurrence and severe complications, for instance paraplegina and kyphosis [1-2]. The general therapeutic principles include early diagnosis, complete removal of tumor, and postoperative chemotherapy. Accurate preoperative localization of metastases based on radiographic information are important in the surgical treatment [3-5]. Visible simulation surgery has been applied in surgical fields, especially for orthopedics and neurologic surgery. The purpose of this study was to determine the best surgical plan to treat lumbar metastatic malignant tumor by three-dimensional reconstruction based on 64-slice helical computed tomography (CT) and a simulated operative process. SUBJECTS AND METHODS Design An imaging experiment. Time and setting Experiments were performed in Department of Orthopedics, Chongqing Fuling Central Hospital in China from January to August in 2013. Subjects An 8-year-old male patient with vertebral metastases who were hospitalized in Department of Orthopedics, Chongqing Fuling Central Hospital in China was included in this study. This patient was diagnosed L 4 lumbar metastatic poorly differentiated adenocarcinoma with the biopsy guided by CT. The present study was approved by the Ethical Committee of Chongqing Fuling Central Hospital. 7844 P.O. Box 10002, Shenyang 110180

Methods Clinical material and CT scanning Radiographic data were collected by 64-slice helical CT (Philips Brilliance 64; Philips Mecial Systems, Eindhoven, The Netherlands; Figure 1A). The CT technique involved scanner settings of 300 ma and 120 kv, thickness 5 mm, interval 5 mm, 0.984 pitch, and rotation speed 0.5 s/cycle. Three-dimensional reconstruction of the vertebrae and adjacent organs The involved patient was scanned with Philip 64-layer CT at the internal of 0.5 mm and matrix of 1 024 1 024. Totally 374 pictures were acquired, and primitive data of CT picture were stored in Dicom format and input to Mimics 12.1 software (Materialise, Leuven, Belgium). Each deck contour line was extracted automatically after defining bone tissue threshold. Every layer of picture would be processed by parting edge, editing selectively, repairing the hole and removing the redundant data, then we got the mask of skeleton three-dimensional, the mask of adjacent organs would be acquired by region growing and dynamic region growing. These masks were carried out three-dimensional calculation (Figure 1B). After smoothing with the free-form modeling system, its structure became clearer. Visible simulation surgery for vertebral metastases We finished visible simulation surgery in the MedCAD menu of Mimic software. Firstly, vertebral metastases was complete removed via the anterior approach (Figure 2A), according to the measured three-dimensional distance (Figure 2B), we chose suitable titanium mesh filled with PMMA to reset intervertebral space (Figure 2C). Secondly, based on anatomical parameter, the posterior pedicle screw fixations provided spinal stability by reinforcing the posterior tension band pedicle screw (Figure 2D). Finally, the simulated operation helped us predict the difficulties that may be encountered in the real operation process and what precautions to take, which contribute to determine the optimal operation planning. Main outcome measures Three-dimensional reconstruction images in Dicom format were observed. RESULTS Quantitative analysis of subjects A male patient was involved in the final analysis. Three-dimensional reconstruction of the vertebrae and adjacent organs Three-dimensional reconstruction images of the vertebrae and adjacent organs were acquired from all directions and multiple angles (Figure 3A, B). After smoothing with the free-form modeling system, its structure became clearer; and all of the structures, including normal vertebrea, vertebral metastases (L 4), abdominal aorta and kidneys were reconstructed in three dimensions. The three-dimensional of vertebral metastases could be amplified, rotated, and hyalinized to clarify the anatomic character of structure with omnidirectional, multiple-angle, and multilevel views. After we localized the vertebral metastases, an optimal surgical option was chosen. We obtained morphometric measurements of the apex and the axis of the pedicles of lumbal vertebrae L 4 to L 5, the tilt angle, chose suitable insert point of the screw, the depth and the diameter of the screw (Figure 3C, D). DISCUSSION Thoracic vertebra and lumbar vertebra are the common area for spinal tumor, especially thoracic vertebra, tumor destroy most part of the front column. The most frequent presentation is axial spinal pain [6]. Management is guided by three key issues: neurologic compromise, spinal instability, and individual patient factors. In the management of spinal metastases bringing about neurological symptoms and signs, palliative surgical treatment plays an important role. The goals of surgery are preservation of neurological function especially that of the mobility, pain relief and local tumor control. No treatment has been proven to increase the life expectancy of patients with spinal metastasis [5-6]. The goals of therapy are pain control and functional preservation. The main goal in the management of spinal metastatic deposits is always palliative rather than curative, with the primary aim being pain relief and improved. In our study, lower back pain of patient last for more than a month, without neurologic presentation. Recently, with the development of spinal surgery, surgical intervention includes excision of tumor by anterior approach, transpedicle fixation by posterior approach. During transpedicle fixation, correct implantation of the screws without perforation of the pedicle is difficult and requires detailed anatomic knowledge and good surgical skills [7-10]. The identification of the correct entry point for the pedicle screw and the angle of inclination in the sagittal and transverse planes are crucial [11-12]. In the past, we got the medical information from X-ray, CT and MRI, which is not actual or intact [13]. With the rapid development of computer technology, virtual reality technology plays an important role in medicine. In clinical practice, in order to avoid direct human surgical strategy, the best solution is to set up a virtual simulation system [14-15]. Using virtual simulation system based on three-dimensional medical visual model, we can get all the anatomic parameter of tumor and pedicle, with these help, transpedicle screw implantation was accurate. Moreover, according to the three-dimensional measurement, distance between abdominal aorta and tumour is 21.87 mm, so we must be careful to disposal lumbar artery during removal of the tumor by anterior approach [16-18]. In a word, utilizing virtual imaging technology with the aid of Mimics which generates virtual images, a three-dimensional model was produced with the CT images. A preoperative planning for excision of vertebral ISSN 2095-4344 CN 21-1581/R CODEN: ZLKHAH 7845

A B C D Figure 2 Three-dimensional measurement of titanium mesh diameter and length using Mimics 10.0 software, measurement of L 3 and L 5 pedicle transverse and sagittal diameters in patients of vertebral metastases, and determination of pedicle inclined angle and horizontal angle Note: A: Removal of metastases. B: Three-dimensional measurement. C: Titanium mesh filled with PMMA. D: Trans-pedicle internal fixation. A B C D Figure 3 Three-dimensional reconstruction images in patients of vertebral metastases based on Dicom format Note: A: Three-dimensional of abdominal region. B: Three-dimensional of abdominal region (hyalinized). C: Simulation surgery (hyalinized). D: Simulation surgery (lateral). These pictures re-visualize the structure of affected vertebrae and adjacent organs. The virtual simulation operation is very direct and accurate to reconstruct three-dimensional structure of affected vertebrae and adjacent organs, to define the range of affected lesions, and is conductive to spinal reconstruction via the posterior approach. A Figure 1 Radiographic findings of a patient with vertebral metastases Note: A is CT scanning image; B is three-dimensional image using Mimics 12.1 software. metastases, spinal reconstruction planning with minimally invasive was made. Virtual reality has brought new proportions in three-dimensional planning and management of various complex problems that are faced during various operations. Integration of three-dimensional imaging with virtual reality makes understanding the complex anatomy easier and helps improve decision making in patient management [19-45]. Virtual simulation surgery of vertebral metastases provides surgeon more objective information, to help them adopt the individual strategy for every patient. 7846 B REFERENCES [1] Borani S, Weinstein JN, Biagini R. Primary bone tumor of thespine. Spine. 1997;22(9):1036-1044. [2] Boriani S, Bandiera S, Biagini R, et al. Staging and treatment of primary tumors of the spine. Current Opinion in Orthopedics. 1999;10(2):93-100. [3] Doh JW, Halliday AL, Baldwin NG, et al. Spinal stabilization by using crossed-screw anterior-posterior fixation after multisegmental total Spondylectomy for thoracic chondrosarcoma: case report. J Neurosury. 2001;94(Suppl): 279-283. [4] Tomita K, Kawahara N, Kobayashi T, et al. Surgical strategy for spinal metastases. Spine. 2001;26:298-306. [5] Abe E, Kobayashi T, Murai H, et al. Total spondylectomy for primary malignant, aggressive benign, and solitary metastatic bone tumor of the thoracolumbar spine. J Spine Disorder. 2001;14:237-246. [6] Wang Q, Song Y, Zhuang H, et al. Robotic stereotactic irradiation and reirradiation for spinal metastases: safety and efficacy assessment. Chin Med J (Engl). 2014;127(2): 232-238. [7] Bohinski RJ, Rhines L. Principles and techniques of enblocvertebrectomy for bone tumors of the thoracolumbar spine: an overview. Neurosurg Focus. 2003;15(5):1-6. [8] Amiot LP, Lang K, Putzier M, et al. Comparative results between conventional and computer-assisted pedicle screw installation in the thoracic, lumbar and sacral spine. Spine. 2000;25:606-614. P.O. Box 10002, Shenyang 110180

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[44] Zinser MJ, Mischkowski RA, Dreiseidler T, et al. Computer-assisted orthognathic surgery: waferless maxillary positioning, versatility, and accuracy of an image-guided visualisation display. Br J Oral Maxillofac Surg. 2013;51(8):827-833. [45] Dores AR, Almeida I, Barbosa F, et al. Effects of emotional valence and three-dimensionality of visual stimuli on brain activation: an fmri study. NeuroRehabilitation. 2013;33(4):505-512. 虚拟仿真技术构建三维模型在腰椎转移性肿瘤中的应用 刘登均 1, 贺小兵 1, 王明贵 1, 李争艳 1, 李奇 2, 林荔军 2 ( 1 重庆市涪陵中心医院骨科, 重庆市 408000; 2 南方医科大学珠江医院骨科中心, 广东省广州市 510282) 刘登均,1983 年生, 男, 重庆市人, 2010 年南方医科大学毕业, 主治医师, 主要从事关节外科与数字医学的研究 通讯作者 : 刘登均, 重庆市涪陵中心医院骨科, 重庆市 408000 文章亮点 : 1 虚拟现实技术集成了计算机图形技术 计算机仿真技术 人工智能 传感技术 显示技术 网络并行处理等技术的最新发展成果, 是一种由计算机技术辅助生成的高技术模拟系统, 是人们通过计算机对复杂数据进行可视化操作与交互的一种全新方式, 与传统的人机界面以及流行的视窗操作相比, 虚拟现实在技术思想上有了质的飞跃 实验通过此方法来寻找一种实行经前后路联合治疗腰椎转移性肿瘤的途径 2 文章通过 Mimics 软件三维重建技术 三维测量功能为最后手术入路的选择 脊柱的重建 手术方案的制定提供一客观而科学的评估方法 文章在三维重建的可视化模型进行虚拟仿真手术操作, 为最后植入支撑钛网选择 后路腰椎序列稳定的重建提供了有效的数字化准备 文章进一步指导了临床手术操作, 为缩短手术时间, 减少手术创伤提供了一条便捷的途径 关键词 : 植入物 ; 数字化骨科 ; 脊柱转移瘤 ; 腰椎 ; Mimics 软件 ; 腹主动脉 ; 肾脏 ; 仿真手术 ; 虚拟现实技术 ; 三维重建主题词 : 组织工程 ; 腰椎 ; 恶性肿瘤 ; 脊柱摘要背景 : 脊柱转移瘤往往破坏椎体和附件, 患者会患有严重的疼痛, 并发症发生率较高, 例如截瘫和脊柱后凸畸形等 脊 柱转移瘤治疗原则是早期诊断, 手术完全切除, 术后化疗 影像学技术如 CT 可判断脊柱转移瘤的转移情况, 进行准确的术前定位 目前可视化仿真手术及虚拟现实技术已经逐渐应用于整形外科领域 目的 : 通过探索虚拟现实技术来寻找一种实行经前后路联合治疗腰椎转移性肿瘤的途径 方法 : 基于腰椎的 64 排螺旋 CT 连续薄层二维图像,Mimics 软件分别重建正常腰椎 破坏病椎 腹主动脉及双侧肾脏的三维可视化结构, 在三维模型拟行经前路病灶清除 钛网骨水泥支撑 后路椎弓根螺钉内固定 结果与结论 : 基于 Dicom 格式数据进行三维重建图像结构清晰, 可真实再现腰椎病椎和邻近脏器的结构, 整个虚拟仿真手术真实直观 虚拟仿真手术准确重建腰椎恶性肿瘤及邻近结构的三维立体结构, 明确病椎清除范围, 经后路重建脊柱序列, 此方法可为个体化的治疗方案提供了客观的依据 作者贡献 : 第一 二 三作者构思设计本实验, 第四作者完成实验, 第一作者起草, 第五 六作者校审, 第一作者对本文负责 利益冲突 : 文章不涉及任何利益冲突 伦理要求 : 根据中华人民共和国国务院颁发的 医疗机构管理条例, 在实验前将实验方案和风险告知对方, 并签署知情同意书 学术术语 : 虚拟现实技术 - 虚拟现实虚拟现实技术, 涉及计算机图形学 人机交互技术 传感技术 人工智能等领域, 它用计算机生成逼真的三维视 听 嗅觉 等感觉, 使人作为参与者通过适当装置, 自然地对虚拟世界进行体验和交互作用 使用者进行位置移动时, 电脑可以立即进行复杂的运算, 将精确的 3D 世界影像传回产生临场感 该技术集成了计算机图形 (CG) 技术 计算机仿真技术 人工智能 传感技术 显示技术 网络并行处理等技术的最新发展成果, 是一种由计算机技术辅助生成的高技术模拟系统, 是人们通过计算机对复杂数据进行可视化操作与交互的一种全新方式, 与传统的人机界面以及流行的视窗操作相比, 虚拟现实在技术思想上有了质的飞跃 虚拟现实中的 现实 是泛指在物理意义上或功能意义上存在于世界上的任何事物或环境, 它可以是实际上可实现的, 也可以是实际上难以实现的或根本无法实现的, 而 虚拟 是指用计算机生成的意思 因此, 虚拟现实是指用计算机生成的一种特殊环境, 人可以通过使用各种特殊装置将自己 投射 到这个环境中, 并操作 控制环境, 实现特殊的目的, 即人是这种环境的主宰 作者声明 : 文章为原创作品, 内容真实, 文责自负 ; 数据准确, 文章内容不涉及泄密, 已由单位审核 ; 无一稿两投, 无抄袭, 无内容剽窃, 无作者署名争议, 无与他人课题以及专利技术的争执 中图分类号 : R318 文献标识码 : B 文章编号 : 2095-4344(2014)48-07844-05 刘登均, 贺小兵, 王明贵, 李争艳, 李奇, 林荔军. 虚拟仿真技术构建三维模型在腰椎转移性肿瘤中的应用 [J]. 中国组织工程研究, 2014,18(48):7844-7848. (Edited by Wang J, Yang Y) 7848 P.O. Box 10002, Shenyang 110180