Experimental microablation of choroidal tissue for autologous retinal pigment epithelium-choroid translocation with the pulsed electron avalanche knife (PEAK-fc).

Abstract

To test the microablation of excess graft choroidal tissue with the pulsed electron avalanche knife (PEAK-fc) in an in-vitro model of autologous retinal pigment epithelium (RPE)-choroid translocation. Choroidal tissue of porcine RPE-choroid explants was ablated with the PEAK-fc. Tissue morphology was assessed by light microscopy (LM) and scanning electron microscopy (SEM). The amount of ablated choroidal tissue was analysed as a function of three PEAK-fc parameters: (1) amplitude of biphasic voltage (70-100%); (2) distance between choroidal tissue and tip of the PEAK-fc (0-300 μm); and (3) exposure time (2-8 s). LM and SEM showed a smooth plain within the ablation area with well defined cutting edges and preserved adjacent tissue structure. The mean amount of ablated tissue correlated linearly with applied voltage (range 79-120 μm, r=0.34) and distance between choroidal tissue and PEAK-fc tip (range 10-100 μm, r=0.74). The mean amount of ablated tissue increased with exposure time between 2 and 4 s (36-88 μm, r=0.4) and remained constant between 4 and 8 s. The PEAK-fc accurately microablates choroidal tissue in-vitro. The adjacent choroidal tissue structure and Bruch's membrane are preserved. Patient studies are required to test the PEAK-fc in RPE-choroid translocation surgery.