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


METHODS
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).


RESULTS
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.


CONCLUSIONS
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.
Department of Ophthalmology, University Medical Center Schleswig-Holstein, Arnold-Heller Strasse 3, Kiel, Germany. ftreumer@auge.uni-kiel.de
Felix
F
Treumer
Benjamin
B
Sattler
Arnd
A
Bunse
Alexa
A
Klettner
Jost
J
Hillenkamp
Johann
J
Roider
D055011:Ablation Techniques / Q000295:instrumentation*; D000818:Animals; D002829:Choroid / Q000637:transplantation*; D008855:Microscopy, Electron, Scanning; D055213:Retinal Pigment Epithelium / Q000637:transplantation*; D013552:Swine; D014182:Transplantation, Autologous