Eyeworld

EW RETINA 46 by Matt Young and Gloria D. Gamat EyeWorld Contributing Writers Such promising results are just the beginning of many validation studies before this potentially new application of the da Vinci robot can be utilized in clinical practice. "We are in the process of con- ducting a study to better evaluate the success rate for performing sub- retinal injections with a convention- ally configured da Vinci system," Dr. Foster said. In addition, Dr. Foster empha- sized that his group doesn't have a patent on the method or the robot, and so he would welcome "competi- tors" to help move this idea forward. "We already have all kinds of lasers and instrumentation to perform most eye surgeries. I see the da Vinci robot as primarily allow- ing physicians to safely administer subretinal injections to patients [i.e., injections of viral vectors, stem cell derived cells, or cells that release a drug or growth hormone]. When we validate this procedure, surgeons can immediately utilize the robot [off-label] for this application," he concluded. EW Editors' note: The physicians have no financial interests related to this article. Contact information Eun: daniel.eun@tuhs.temple.edu Foster: william.foster@temple.edu Its 10:1 stepdown affords increased accuracy of the surgeon's move- ments, which reduces complications related to human tremor and yields increased precision." The team used a Thornton fixation ring to stabilize the globe, and the da Vinci camera was used to directly visualize the retina. Subretinal injection of ICG dye was administered and visualized directly with the ICG filters on the da Vinci system. "The injection was made using a repurposed butterfly needle, which was grasped and maneuvered by the needle driver tool of the da Vinci system. The injection itself was performed by hand using a 10 cc syringe attached to the tube of the butterfly needle," the team explained. Testing in porcine models, Dr. Foster and colleagues demonstrated that transscleral, subretinal injection using the da Vinci robot is possible, although appropriate modification of the instrument is necessary. "Our results suggest that ro- botically assisted, transchoroidal delivery of viral vectors for gene therapy may be effective in reducing the incidence of retinal detachment and other adverse outcomes," they reported. There are 2 ways to place some- thing into the subretinal space, Dr. Foster said: either perform a vitrec- tomy, go through the middle of the "eyeball" and make a hole in the retina at the back of the eye (trans- vitreal), or insert the needle through the eye wall until it is just under the retina (transscleral). "While some retina surgeons routinely drain or remove fluid from under the retina in a transscleral manner, approaching attached retina in this manner requires very controlled movements that are com- pletely without a tremor," Dr. Foster explained. Further, ophthalmologists and other scientists have been increas- ingly making great strides in the area of gene therapy, and the need to deliver genes directly to the retina is thus increasing. "These treatments often benefit children more than adults. Perform- ing a vitrectomy and making a hole in the retina in a child is problem- atic; it more commonly leads to a retinal detachment and blindness," Dr. Foster said. "I realized that a robot, which is otherwise quite slow for many eye surgeries, is ideal for this application." Meanwhile, at the Department of Urology at Temple University, Daniel Eun, MD, chief of robotic surgery, director of minimally inva- sive robotic urological oncology, and associate professor of urology, has a reputation for novel uses of the da Vinci robot. "He has a laboratory with 6 da Vinci robots where robotic surgery is taught using a porcine model. I vis- ited Dr. Eun in his operating room and we struck up a collaboration," Dr. Foster said. Promising preliminary results The collaboration has led to testing techniques that would make retinal injections possible without creating a hole in the retina. "But transchoroidal, subretinal injections, which avoid making a retinal hole, also require extremely precise positioning of the needle," the team reported at the 2015 ARVO annual meeting. "Therefore, we have attempted to reproduce this procedure using the da Vinci robot. Robot spearheaded in other fields comes to ophthalmology in a precise way A t the dawn of a new millennium, the da Vinci Surgical System (Intuitive Surgical, Sunnyvale, Ca- lif.) broke robotic surgery history when it became the first robotic surgical system approved by the U.S. Food and Drug Administra- tion (FDA) for minimally invasive general surgery. Since the year 2000, minimally invasive surgery using the da Vinci robot has made the rounds of appli- cations in various medical special- ties. The da Vinci robot is increas- ingly becoming standard equipment in many operating rooms, and that may soon include more ophthalmic operating rooms. At the 2015 Association for Research in Vision and Ophthalmol- ogy (ARVO) annual meeting, a team of experts from Temple University presented the potential use of the da Vinci robot in transscleral, subreti- nal injections. Development of the "robot idea" The group, led by William J. Foster, MD, PhD, professor of ophthalmol- ogy and bioengineering, Temple University, Philadelphia, thought that because robots are expensive, a robot already being used for one purpose in a given hospital is more likely to be practically applied to another purpose, rather than asking the hospital to purchase a special- purpose robot for a rare use. "One of my primary goals was to involve medical students in a fun research project that may later impact my patients," Dr. Foster said. "Besides, the da Vinci systems are usually utilized in a fairly low resolu- tion mode, where they reduce the surgeons' movements by only about 4:1. By inexpensively modifying the da Vinci software, it should be possi- ble to improve the capability of the robot for this application, and such a software upgrade is more likely to be accepted by hospital administra- tion than purchase of an entirely new system." Transscleral and subretinal injections, the da Vinci robot way Dr. Eun using the da Vinci system Source: Daniel Eun, MD February 2016

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