Results from the first trial of robotic retina surgery in humans are in, and researchers at the at the University of Oxford in England have reported that membrane dissection takes about four times longer with the robotic device than manual surgery, and that the difference in the amounts of microtrauma between the two approaches were statistically insignificant, but the robot showed the potential to deliver other benefits in retinal microsurgery.1 They reported their results in Nature Biomedical Engineering.

The trial utilized the robotic surgery platform that Preceyes BV of Eindhoven, the Netherlands, has been developing in collaboration with Oxford researchers. The researchers performed the trial at Oxford’s John Radcliffe Hospital, involving six patients randomly assigned to robot-assisted surgery and six to standard manual surgery to dissect epiretinal membrane or inner limiting membrane.

In the second phase of the trial, the team used the robot to inject recombinant tissue plasminogen activator subretinally to displace hemorrhage under local anesthesia. In the ILM peels, all holes were closed; in the ERM dissections, all membranes were removed. All study subjects experienced an improvement in their vision as a result.

 
Robert MacLaren, MB, ChB, DPhil, at the console of the retina surgical robot. (Photo Courtesy University of Oxford)
Breaking Down the Operation
‘This is a huge leap forward for delicate and technically difficult surgery, which in time should significantly improve the quality and safety of this kind of operation,” says Robert MacLaren, MB, ChB, DPhil, professor of ophthalmology at Oxford. “The trial also showed that the robot has great potential for extending the boundaries of what we can currently achieve.”

While draping and installing the surgical robot did not disrupt the normal surgical work flow, the average time of the operation—between inserting the first trocar to injecting the subconjunctival antibiotic prior to removing the lid speculum—was 31 minutes for the manual group and 44 minutes for the robot group (p<0.0001).

Specific steps of the operation also took longer with the robot. Moving a pick from the anterior vitreous cavity to a position over the macula where it’s safely poised to engage the membrane took 2 minutes, 22 seconds vs. 12 seconds (p=0.002). Raising the flap of either the ILM or ERM with the pick took 4 minutes, 55 seconds vs. 1 minute, 20 seconds.

The study showed the robot can overcome involuntary movements of the surgeon’s hand. The authors noted, “For instance, while the surgeon routinely needs to engage a needle tip or pair of forceps within the thin (<20 μm) inner limiting membrane of the retina without damaging deeper structures, human physiological tremor is present in the order of 100 μm when transmitted to the instrument tip.” Eliminating those micromovements as a factor could enable new intraocular procedures that require “supra-human levels of precision,” the study authors noted.

Report Due at AAO
Matteo Cereda, MD, a retinal surgeon at Sacco Hospital Eye Clinic in Milan, will report on the robotic platform at the American Academy of Ophthalmology next month in Chicago. Dr. Cereda conducted a feasibility study of the robot’s integrated distance sensor.

Preceyes is also investigating the use of a virtual-reality simulator with the surgical robot as a training tool, and next year the Oxford investigators expect to start a trial using the robotic platform to deliver gene therapy to the retina with a higher degree of precision and less trauma than manual surgery.

Reference
1. Edwards TL. Xie K, Meenink HCM, et al. First-in-human study of the safety and viability of intraocular robotic surgery. Nat Biomed Engin. 2018. Published online June 18.