脊椎椎體椎籠(Vertebral Body Cages)常用於治療脊椎椎體病症，然而，其在臨床應用時會有下陷或滑脫問題，先前的研究已針對脊椎椎籠介面鬆脫問題進行探討，但僅考慮椎籠單一鬆脫失效方向，而脊椎可有不同方位的運動，例如：屈曲、伸展、側彎、扭轉，故椎籠可能會朝不同方向發生鬆脫。因此，本研究的目的為設計一個椎體椎籠，其在任一方向均能提供良好的介面咬合強度。
本研究建立三維非線性有限元素模型，探討椎體椎籠於不同鬆脫方向之介面咬合強度，為減少最佳化過程的時間，以類神經網路建立椎體椎籠介面咬合強度之預測方程式，以取代原有的有限元素模型，最後，使用遺傳演算法搜尋最佳的椎體椎籠設計。本研究將針對有骨融合人工椎體椎籠及無骨融合人工椎體椎籠兩種情況進行討論。最後進行生物力學測試以驗證數值分析的結果。
在數值分析的結果，有骨融合與無骨融合最佳化設計的情況相同，人工椎體椎籠最佳化的端面齒型高度為2mm，齒型寬度為1mm，齒型傾斜程度為0，齒排數為16及人工椎籠內徑為10mm。而在生物力學測試的結果，從有限元素模型求得的總反力與生物力學測試的拉出強度擁有密切的相關性，其相關係數為0.90。
本研究透過類神經網路及遺傳演算法，可準確及有效的搜尋椎體椎籠於不同情況之最佳化設計。最佳化設計結果可供工程人員作為新型設計之參考，並給予醫師選擇合適的手術植入物之依據。

Vertebral body cages (VBCs) have been applied to different vertebral morbidities. However, interface loosening and subsidence of a VBC are the complications after a surgical operation. Generally, the interface pullout strength of VBCs was discussed by exerting a single direction (normally forward and backward) loading. However, the VBC would take the loading from different directions, such as flexion, extension, lateral bending, and axial rotation. Therefore, the purpose of this study was to search the VBC design with excellent interface pullout strength under different situations.
Three-dimensional nonlinear finite element model was developed to simulate the interface pullout strength of VBCs. To decrease the computational time, the artificial neuron network (ANN) was used to substitute the finite element model. The optimum VBC design would be obtained by using genetic algorithms (GAs). Two kinds of the situations are discussed including a VBC with bone fusion and a VBC without bone fusion. The biomechanical tests were done to validate the results of the numerical study.
In the results of the numerical study, the optimal VBC design for the situation of bone fusion was the same as that for the situation without bone fusion. The result of the optimal VBC design was a spike height of 2 mm, a spike width of 1 mm, a spike oblique of 0, 16 spike rows, and an inner diameter of 10 mm. In the results of the biomechanical tests, the total reaction force obtained from the finite element models was closely related to the pullout force obtained from the experiments with a high correlation coefficient of 0.9.
In this study, ANNs and GAs could accurately and effectively predict the interface pullout strength of VBCs under different conditions. The optimum design might be useful information to engineers to develop a new VBC. In addition, this can help surgeons to select a suitable VBC to their patients.

[1] Eck, K. R., K. H. Bridwell, F. F. Ungacta, M. A. Lapp, L. G. Lenke, and K. D. Riew, "Analysis of titanium mesh cages in adults with minimum two-year follow-up," Spine (Phila Pa 1976), vol. 25, pp. 2407-15, Sep 15 2000.
[2] Lolge, S., "Isolated Solitary Vertebral Body Tuberculosis—Study of Seven Cases," Clinical Radiology, vol. 58, pp. 545-550, 2003.
[3] Liljenqvist, U., T. Lerner, V. Bullmann, L. Hackenberg, H. Halm, and W. Winkelmann, "Titanium cages in the surgical treatment of severe vertebral osteomyelitis," European Spine Journal, vol. 12, pp. 606-612, 2003.
[4] Zhu, Y., H. Zhao, G. X. Qiu, J. G. Zhang, Y. Tian, S. G. Li, and S. M. Yuan, "Single-stage posterior spondylectomy, circumferential decompression and reconstruction using mesh cage for spinal tumors," Chinese Medical Sciences Journal, vol. 24, pp. 172-7, Sep 2009.
[5] Eleraky, M. A., H. T. Duong, E. Esp, and K. D. Kim, "Expandable Versus Nonexpandable Cages for Thoracolumbar Burst Fracture," World Neurosurgery, vol. 75, pp. 149-154, 2011.
[6] Albers, P., D. Melchior, and S. C. Muller, "Surgery in Metastatic Testicular Cancer," European Urology, vol. 44, pp. 233-244, 2003.
[7] Ramirez, J. J., E. Chiquete, J. J. Ramirez Jr, E. Gomez-Limon, and J. M. Ramirez, "An Expandable Prosthesis with Dual Cage-and-Plate Function in a Single Device for Vertebral Body Replacement: Clinical Experience on 14 Cases with Vertebral Tumors," Archives of Medical Research, vol. 41, pp. 478-482, 2010.
[8] Acosta, F. L., Jr., H. E. Aryan, D. Chou, and C. P. Ames, "Long-term biomechanical stability and clinical improvement after extended multilevel corpectomy and circumferential reconstruction of the cervical spine using titanium mesh cages," Journal of Spinal Disorders & Techniques, vol. 21, pp. 165-74, May 2008.
[9] Choi, J. Y. and K. H. Sung, "Subsidence after anterior lumbar interbody fusion using paired stand-alone rectangular cages," European Spine Journal, vol. 15, pp. 16-22, 2005.
[10] Fayazi, A., "Preliminary results of staged anterior debridement and reconstruction using titanium mesh cages in the treatment of thoracolumbar vertebral osteomyelitis," The Spine Journal, vol. 4, pp. 388-395, 2004.
[11] Gercek, E., V. Arlet, J. Delisle, and D. Marchesi, "Subsidence of stand-alone cervical cages in anterior interbody fusion: warning," European Spine Journal, vol. 12, pp. 513-516, 2003.
[12] Kast, E., S. Derakhshani, M. Bothmann, and J. Oberle, "Subsidence after anterior cervical inter-body fusion. A randomized prospective clinical trial," Neurosurgical Review, vol. 32, pp. 207-214, 2008.
[13] Diacinti, D., D. Pisani, F. Barone-Adesi, R. Del Fiacco, S. Minisola, V. David, G. Aliberti, and G. F. Mazzuoli, "A new predictive index for vertebral fractures: The sum of the anterior vertebral body heights," Bone, vol. 46, pp. 768-773, 2010.
[14] Wilke, H. J., K. Wenger, and L. Claes, "Testing criteria for spinal implants: recommendations for the standardization of in vitro stability testing of spinal implants," European Spine Journal, vol. 7, pp. 148-54, 1998.
[15] 游祥明、宋晏仁、古宏海、傅毓秀、林光華, 解剖學 華杏出版股份有限公司, 2005.
[16] Approach, D. V. S. F. A. http://www.youtube.com/watch?v=SYwPyoDIEfM&feature=related.
[17] Vahldiek, M. J. and M. M. Panjabi, "Stability Potential of Spinal Instrumentations in Tumor Vertebral Body Replacement Surgery," SPINE, vol. 23, pp. 543-550, 1998.
[18] Grob, D., S. Daehn, and A. F. Mannion, "Titanium mesh cages (TMC) in spine surgery," European Spine Journal, vol. 14, pp. 211-21, Apr 2005.
[19] Chuang, H., D. Cho, C. Chang, W. Lee, C. Jungchung, H. Lee, and C. Chen, "Efficacy and safety of the use of titanium mesh cages and anterior cervical plates for interbody fusion after anterior cervical corpectomy," Surgical Neurology, vol. 65, pp. 464-471, 2006.
[20] Lange, U., S. Edeling, C. Knop, L. Bastian, M. Oeser, C. Krettek, and M. Blauth, "Anterior vertebral body replacement with a titanium implant of adjustable height: a prospective clinical study," European Spine Journal, vol. 16, pp. 161-172, 2006.
[21] Tan, J. S., C. S. Bailey, M. F. Dvorak, C. G. Fisher, and T. R. Oxland, "Interbody device shape and size are important to strengthen the vertebra-implant interface," Spine (Phila Pa 1976), vol. 30, pp. 638-44, Mar 15 2005.
[22] Rohlmann, A., T. Zander, and G. Bergmann, "Effects of fusion-bone stiffness on the mechanical behavior of the lumbar spine after vertebral body replacement," Clinical Biomechanics, vol. 21, pp. 221-227, 2006.
[23] Akamaru, T., N. Kawahara, J. Sakamoto, A. Yoshida, H. Murakami, T. Hato, S. Awamori, J. Oda, and K. Tomita, "The transmission of stress to grafted bone inside a titanium mesh cage used in anterior column reconstruction after total spondylectomy: a finite-element analysis," Spine (Phila Pa 1976), vol. 30, pp. 2783-7, Dec 15 2005.
[24] Reinhold, M., W. Schmoelz, F. Canto, D. Krappinger, M. Blauth, and C. Knop, "A new distractable implant for vertebral body replacement: biomechanical testing of four implants for the thoracolumbar spine," Archives of Orthopaedic and Trauma Surgery, vol. 129, pp. 1375-1382, 2009.
[25] Hsu, W.-H., C.-K. Chao, H.-C. Hsu, J. Lin, and C.-C. Hsu, "Parametric study on the interface pullout strength of the vertebral body replacement cage using FEM-based Taguchi methods," Medical Engineering & Physics, vol. 31, pp. 287-294, 2009.
[26] 李錟鋒, 電腦輔助工程應用-有限元素分析 新科技書局, 1992.
[27] 張斐章、張麗秋, 類神經網路 東華書局, 2006.
[28] 林昇甫、徐永吉, 遺傳演算法及其應用 五南圖書出版股份有限公司, 2009.
[29] Sawbones. http://www.sawbones.com/.
[30] 楊惠齡、林明德, 生物統計學(第七版) 新文京開發出版股份有限公司, 2009.
[31] 蔣力, "人工椎體椎籠之介面拉出強度之最佳化設計：考慮不同滑脫方向," 國立台灣科技大學機械工程系碩士論文, 2010.