Robotic Assisted Cannulation of Occluded Retinal Veins

Abstract

PurposeTo develop a methodology for cannulating porcine retinal venules using a robotic assistive arm after inducing a retinal vein occlusion using the photosensitizer rose bengal.MethodologyRetinal vein occlusions proximal to the first vascular branch point were induced following intravenous injection of rose bengal by exposure to 532nm laser light delivered by slit-lamp or endolaser probe. Retinal veins were cannulated by positioning a glass catheter tip using a robotically controlled micromanipulator above venules with an outer diameter of 80μm or more and performing a preset piercing maneuver, controlled robotically. The ability of a balanced salt (BSS) solution to remove an occlusion by repeat distention of the retinal vein was also assessed.ResultsCannulation using the preset piercing program was successful in 9 of 9 eyes. Piercing using the micromanipulator under manual control was successful in only 24 of 52 attempts, with several attempts leading to double piercing. The best location for cannulation was directly proximal to the occlusion. Infusion of BSS did not result in the resolution of the occlusion.ConclusionCannulation of venules using a robotic microassistive arm can be achieved with consistency, provided the piercing is robotically driven. The model appears robust enough to allow testing of therapeutic strategies aimed at eliminating a retinal vein thrombus and its evolution over time.

A Subretinal Cell Delivery Method via Suprachoroidal Access in Minipigs: Safety and Surgical Outcomes

“…23 Robotic-assisted surgical solutions may mitigate these challenges by providing high positional stability in all primary directions. 31,32 Positional stability also eliminates the need to proceed quickly with the injection, a requirement of manual procedures that may limit the applicability of any transvitreal injection technique in scarred retina. The association of robotics assistance with smart positioning devices or its combination with optical coherence tomography can further increase the precision of such deliveries in the future.…”

Release of experimental retinal vein occlusions by direct intraluminal injection of ocriplasmin

“…In the presence of an intact posterior hyaloid, it would add an additional level of security as it would limit any haemorrhage to the immediate perivascular area. The robotic arm facilitates the procedure by precisely controlling the advancement of the catheter to the occluded vein with a positional precision of under 10 µm, filtering out tremor, scaling motion, and automating critical steps 10. In the current experiments, a specific piercing protocol insured that the superficial wall of the vein was penetrated while avoiding piercing the outer wall of the vessel.…”

“…The venous occlusions were created and confirmed as previously described 10. Briefly, 10 mg/kg of rose bengal (4,5,6,7-tetrachloro-2′,4′,5′,7’-tetraiodo-fluorescein; Sigma-Aldrich: Diegem, Belgium) was injected intravenously.…”

“…Within 1 hour of causing the occlusion, the animal was positioned and prepared for surgery as previously described 10. In brief, the set-up consisted of a standard operating suite including a M822 F40 Leica ophthalmic surgical microscope (Diegem, Belgium), a DORC Associate ACS2500 Dual vitrectomy unit (DORC bv, Zuidland, the Netherlands) coupled to a prototype robotic arm and its controller (PrecEyes bv, Eindhoven, the Netherlands).…”

“…To this end, rose bengal-induced RVO were generated in young pigs, as the pig retinal vasculature has structural characteristics similar to that of humans. To deliver the enzyme to the site of occlusion, retinal venules were cannulated before the site of occlusion with the assistance of a robotic micromanipulator, which is able to compensate for physiologic tremor while providing needed positional stability required for prolonged infusions 10. Herein we report the results of these initial experiments.…”