Investigation of Surgical Techniques for Optimization of Long-Term Outcomes of LCP-Based Retinal Prosthesis Implantation

Abstract

PurposeTo investigate reproducible surgical techniques to optimize the long-term safety of liquid crystal polymer (LCP)-based retinal prosthesis implantation.MethodsAn LCP-based retinal prosthesis is fabricated monolithically on a single-body LCP substrate with all components, including the package and electrode array. We implanted the electrode array into the suprachoroidal space and anchored the package and transition part to the sclera in rabbits (n = 11). The safety profile was assessed upon the completion of the surgery and postoperatively.ResultsThe surgical procedures for implantation of the entire system were easily performed in nine eyes (81.8%) without any intraoperative complications. In the other two eyes (18.2%), surgical complications related to electrode insertion, including optic nerve damage and retinal tear, arose. In 10 eyes (90.9%), the devices were well tolerated for at least 3 months. However, in most eyes (nine; 81.8%), two complications began to appear after 3 months, postoperatively, including conjunctival erosion or dehiscence over the package or transition part. The electrode arrays were maintained safely in the suprachoroidal space after surgery without any complications, regardless of the status of the extraocular components in all cases except two intraoperative complications.ConclusionsWe established safe and reproducible surgical techniques for implantation of our LCP-based retinal prosthesis into the suprachoroidal space. Although issues related to surgical technique or device configuration were identified, further technical solutions would improve the long-term safety of device implantation.Translational RelevanceThis study presents successful implantation of LCP-based retinal prosthesis. The technical solutions will permit an optimization of surgical techniques.

Emerging Encapsulation Technologies for Long-Term Reliability of Microfabricated Implantable Devices

“…The thermoplasticity of LCP can be utilized to create a non-planar structure for conformation to target tissues by a simple thermoforming process, and to rapidly form a multilayered structure by stacking independently prepared LCP layers and thermally pressing them to bond together. The potential of LCP has been demonstrated in wide range of applications in neural engineering such as a miniaturized all-LCP retinal implant with an eye-conformable structure [125] as well as various shapes of neural electrode arrays for cortical [126,127], cochlear [128,129], intraocular [130,131,132], and peripheral applications [133,134,135].…”