Surgical Design Considerations for Implantation of Model 1 Retinal Prosthesis

Abstract

Abstract: : Purpose:To describe the surgical technique for implantation of the Second Sight Model 1 Retinal Prosthesis. Methods: All 6 patients included in this study were adults with confirmed retinal degenerative disease. The surgery was performed on the worse–seeing eye, which had no better than light perception vision. The device is comprised of both intraocular and extraocular components. External hardware captures images and transmits them to a receiving device (ICS). From there, the image data is sent via a small wire to the retinal platinum/silicone 16–electrode array. A posterior based U–shaped flap is made behind the ear through skin and subcutaneous tissue down to the level of temporalis fascia. A temporalis muscle flap is then elevated anteriorly and pedicled down toward the zygomatic arch with a self–retaining retractor. This results in exposure of the squamous part of the temporal bone. A metal template is placed on the bone and outlined. Next, a 5mm round ball cutting burr is used to completely remove the lateral cortex of the skull in that region. This creates a well of sufficient depth to accommodate the receiver package without a high device profile. A channel is then created to protect the electrode cable as it tunnels forward. This channel is drilled from the anterior portion of the ICS well underneath the temporalis muscle to the orbital rim. The ICS is secured in place with 2–0 monofilament sutures. The electrode array is introduced through the tunnel into the posterior orbit. Intra–orbital cable wire is passed beneath all four rectus muscles. Following vitrectomy, the electrode array is secured to the epiretinal surface. Results: The intraocular retinal prosthesis was successfully implanted in all 6 cases without complication. At the time of abstract submission, all implanted prostheses were intact and functional. Conclusions: This surgical technique delineates a multidisciplinary approach to biomedical device implantation. It achieves stable device fixation, does not hinder ocular motility, decreases the risk of device damage, avoids patient disfigurement, minimizes discomfort, and allows proper function of the implant.

Keywords: retina • clinical (human) or epidemiologic studies: systems/equipment/techniques • clinical (human) or epidemiologic studies: outcomes/complications