Eyeworld

EW NEWS & OPINION 26 October 2017 Research highlight by Liz Hillman EyeWorld Staff Writer Bourcier said. Specific instruments for robotic ophthalmic surgery have to be created, an injection system needs to be developed, and in- creased precision to the micrometer level, haptic feedback, backlight, laser, imaging, and safety systems would be beneficial. What's more, set-up time, surgical time, and cost of the system would need to be more efficient. In November 2016, Cambridge Consultants, a product development company in Cambridge, U.K., built Axsis, a robotic system that incorpo- rates several different design ideas to show how one could build a smaller surgical robot for eye surgery. Chris Wagner, PhD, head of ad- vanced surgical systems, Cambridge Consultants, said many current surgical robots are large, requiring a lot of space, take a lot of time to set up, disrupting the normal surgical workflow, and at times pose a safety risk as most have long arms moving around the room. With Axsis, Dr. Wagner said, Cambridge Consultants wanted to show how to design a small surgical robot that could perform surgery in an extremely tiny space. To accomplish this, Axsis uses curved, flexible surgical instruments instead of long, thin, rigid ones typically used in robotic surgery. This, he said, eliminated the issue of large motion occurring around the room. They also employed a parallel architecture, instead of a serial chain manipulator, as a design principle, which allowed the motors, and thus the robot, to become much smaller. In addition to their own innova- tion with the system, commoditiza- tion of components for the various pieces, improvements in machining capabilities, and expense reduction allowed the engineers at Cambridge robotic tool to hold and push at the same time." The human surgeon also con- trolled the da Vinci Xi robot with two telemanipulation handles. Ac- cording to the paper, "master-slave controls replicate the surgeon's hand motions, filtering tremor and offering the possibility of using an adjustable motion-scale ratio." Setting up the robot for sur- gery with the phacoemulsification machine and the wet lab training system took 60 minutes, according to Bourcier et al. The phaco hand- piece was strapped to one of the robot's arms with adhesive tape, and three custom-made instruments—a keratome, cystotome, and manipu- lator—were also attached to robotic arms. The surgery took about 26 minutes, on average, plus or minus 5 minutes per case. The researchers reported that the robotic system created a capsulorhexis of adequate size and shape without radialization, but a perfectly round shape was not achieved because a cystotome was used, not capsulorhexis forceps. The reported main complication of the simulated surgery were two cases of inadvertent enlargement of the main corneal incision by the phaco handpiece. Dr. Bourcier said the learning curve to get acquainted with the da Vinci Xi system for surgery was "rather fast." "Its utilization is quite intui- tive," he said. "Moreover, the prac- tice of microsurgery has been shown to facilitate the learning of robotic surgery. Courses are mandatory to understand and facilitate the contact with this new technology." Despite adequately performing most parts of phacoemulsification cataract surgery in the simulations, improvements are needed, Dr. filtration, automation of movement, better ergonomics, improved patient access to surgeons (telesurgery), and surgical training (telementoring)," said the study's lead author Tristan Bourcier, MD, PhD, professor of ophthalmology, Strasbourg Univer- sity Hospital. "As a result, robotics could improve patient care." Dr. Bourcier and his fellow investigators performed cataract sur- gery using the da Vinci Xi Surgical System and the Whitestar Signature phacoemulsification system (John- son & Johnson Vision, Santa Ana, California) on 25 lens nuclei in a wet lab setting. The robotic system was able to perform the main steps of cataract surgery, making corneal incisions and the capsulorhexis, nuclear disas- sembly and removal, and irrigation/ aspiration. A human surgeon inject- ed ophthalmic viscoelastic device, balanced salt solution, and the intraocular lens by hand because, as Dr. Bourcier put it, "there is no Study and proof-of-concept show feasibility of robotic cataract surgery T he world's first cases of ro- bot-assisted ocular surgery took place in June 2014 at the Strasbourg Univer- sity Hospital, Strasbourg, France, using the da Vinci Xi Surgical System (Intuitive Surgical, Sunnyvale, California). They includ- ed several types of ocular surface surgery such as pterygium surgeries 1 and amniotic membrane transplan- tations. 2 Taking it a step further, a recent study published by the University team in Strasbourg in the Journal of Cataract & Refractive Surgery took a look at the feasibility of robot-assist- ed cataract surgery. 3 "There are many potential ad- vantages of robotics in cataract and eye surgery such as increased pre- cision and maneuverability, tremor The "robolution" is upon us Dr. Amescua views this as a potentially exciting new possibility. "I'm collaborating with the labora- tory of our director of microbiology, Darlene Miller, and the biophysics lab of Jean-Marie Parel, PhD, and we are in the process of trying to start a formal IRB approved prospective study," he said. "The preliminary data so far shows optimistic results." Further study is needed to prove that this is something with staying power that will indeed help patients, he concluded. EW References 1. Amescua G, et al. Rose bengal photody- namic antimicrobial therapy: A novel treatment for resistant Fusarium keratitis. Cornea. 2017;36:1141–1144. 2. Arboleda A, et al. Assessment of rose bengal versus riboflavin photodynamic therapy for inhibition of fungal keratitis isolates. Am J Ophthalmol. 2014;158:64–70. 3. Halili F, et al. Rose bengal- and ribofla- vin-mediated photodynamic therapy to inhibit methicillin-resistant Staphylococcus aureus keratitis isolates. Am J Ophthalmol. 2016;166:194–202. Editors' note: Dr. Amescua has no financial interests related to his comments. Contact information Amescua: gamescua@med.miami.edu New continued from page 24

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