Fox Kate, Meffin Hamish, Burns Owen, Abbott Carla J, Allen Penelope J, Opie Nicholas L, McGowan Ceara, Yeoh Jonathan, Ahnood Arman, Luu Chi D, Cicione Rosemary, Saunders Alexia L, McPhedran Michelle, Cardamone Lisa, Villalobos Joel, Garrett David J, Nayagam David A X, Apollo Nicholas V, Ganesan Kumaravelu, Shivdasani Mohit N, Stacey Alastair, Escudie Mathilde, Lichter Samantha, Shepherd Robert K, Prawer Steven
School of Physics, University of Melbourne, Melbourne, Victoria, Australia.
School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Melbourne, Victoria, Australia.
Artif Organs. 2016 Mar;40(3):E12-24. doi: 10.1111/aor.12582. Epub 2015 Sep 29.
Successful visual prostheses require stable, long-term attachment. Epiretinal prostheses, in particular, require attachment methods to fix the prosthesis onto the retina. The most common method is fixation with a retinal tack; however, tacks cause retinal trauma, and surgical proficiency is important to ensure optimal placement of the prosthesis near the macula. Accordingly, alternate attachment methods are required. In this study, we detail a novel method of magnetic attachment for an epiretinal prosthesis using two prostheses components positioned on opposing sides of the retina. The magnetic attachment technique was piloted in a feline animal model (chronic, nonrecovery implantation). We also detail a new method to reliably control the magnet coupling force using heat. It was found that the force exerted upon the tissue that separates the two components could be minimized as the measured force is proportionately smaller at the working distance. We thus detail, for the first time, a surgical method using customized magnets to position and affix an epiretinal prosthesis on the retina. The position of the epiretinal prosthesis is reliable, and its location on the retina is accurately controlled by the placement of a secondary magnet in the suprachoroidal location. The electrode position above the retina is less than 50 microns at the center of the device, although there were pressure points seen at the two edges due to curvature misalignment. The degree of retinal compression found in this study was unacceptably high; nevertheless, the normal structure of the retina remained intact under the electrodes.
成功的视觉假体需要稳定、长期的附着。尤其是视网膜外假体，需要附着方法将假体固定在视网膜上。最常见的方法是用视网膜钉固定；然而，视网膜钉会造成视网膜创伤，手术熟练程度对于确保假体在黄斑附近的最佳放置很重要。因此，需要其他附着方法。在本研究中，我们详细介绍了一种用于视网膜外假体的新型磁性附着方法，该方法使用位于视网膜相对两侧的两个假体组件。磁性附着技术在猫动物模型（慢性、不可恢复植入）中进行了试点。我们还详细介绍了一种使用热量可靠控制磁耦合力的新方法。结果发现，随着在工作距离处测得的力成比例地减小，作用在分隔两个组件的组织上的力可以最小化。因此，我们首次详细介绍了一种使用定制磁体将视网膜外假体定位并固定在视网膜上的手术方法。视网膜外假体的位置可靠，其在视网膜上的位置通过在脉络膜上腔位置放置辅助磁体来精确控制。在装置中心，视网膜上方的电极位置小于50微米，不过由于曲率不对准，在两个边缘处可见压力点。本研究中发现的视网膜压缩程度高得令人无法接受；然而，在电极下视网膜的正常结构保持完整。
