Feasibility study on retinal vascular bypass surgery in isolated arterially perfused caprine eye model

Abstract

Purpose To investigate the feasibility of bypassing occluded segments of retinal venous main vessels in isolated, arterially perfused caprine eyes via the closed-sky vitrectomy approach using keratoprosthesis. Methods Isolated caprine eyes were used in this study. For each eye, the retinal vessel was perfused by Krebs solution via ophthalmic artery, and pars plana vitrectomy was performed using temporary keratoprosthesis. All retinal micro-vascular maneuvers were performed in a closed-sky eyeball. The main retinal vein was blocked by endodiathermy at the site of the vessel's first branching. Two openings, several millimeters apart, were created by vascular punctures in both the main vein and its branch vein wall straddling the induced occluded segment. Catheterization was achieved using a flexible polyimide tube, with each end inserted into the vessel wall opening. A sealed connection between the vessel and the tube was obtained by endodiathermy. Bypass of the occluded retinal vein segment was thus achieved, and the patency of this vascular bypass was confirmed by intravascular staining. Results Puncturing, catheterization, and endodiathermy were viable by closed-sky approach using keratoprosthesis. Bypassing of the occluded retinal main vein segment was accomplished with the combination of these maneuvers. Good results were obtained in 23 of 38 (60%) caprine eyes. Conclusions This study demonstrated that bypassing the occluded segment of retinal main vein can be successfully performed in a closedsky eyeball model of isolated, arterially perfused caprine eye. This early work indicated that the more advanced retinal vascular bypass surgery in in vivo eye may be feasible in the future.

Feasibility study on robot‐assisted retinal vascular bypass surgery in an ex vivo porcine model

“…, ; Chen et al. ), is emerging as an exciting area of microsurgical intervention that attempts to re‐establish retinal venous outflow. Additional clinical trials will likely substantiate the utility of these approaches.…”

“…Retinal vascular surgery, including sheathotomy (Yamane et al 2014), endovascular injection (Kadonosono et al 2011;Pournaras et al 2012;van Overdam et al 2015) and vascular bypass (Shen et al 2009(Shen et al , 2016Chen et al 2011), is emerging as an exciting area of microsurgical intervention that attempts to re-establish retinal venous outflow. Additional clinical trials will likely substantiate the utility of these approaches.…”

“…Additional clinical trials will likely substantiate the utility of these approaches. In our previous studies (Shen et al 2009(Shen et al , 2016Chen et al 2011), retinal vein bypass manipulation was accomplished using polyimide tubes (50.8-mm internal diameter and 7.6-mm wall thickness) as artificial vascular grafts. Graft patency was achieved in isolated, arterially perfused caprine eyes and living porcine eyes.…”

“…, ; Chen et al. ), retinal vein bypass manipulation was accomplished using polyimide tubes (50.8‐mm internal diameter and 7.6‐mm wall thickness) as artificial vascular grafts. Graft patency was achieved in isolated, arterially perfused caprine eyes and living porcine eyes.…”

Real-time three-dimensional Fourier-domain optical coherence tomography video image guided microsurgeries

“…Each of these vascular isolation techniques are broadly applicable across the field of microsurgery and may become increasingly useful in the field of retinal surgery as ultra-microsurgical techniques become increasingly refined and perfected. 48 …”