Abstract
Abstract: :
Purpose: To minimize the risk for dedifferentiation and subsequent functional impairment atraumatic translocation of peripherally excised autologous RPE patches into the submacular space following CNV excision in AMD is crucial. Clinical application has shown that release of the patch from a transplantation spatula in the subretinal space can be difficult and represents a critical step during the entire procedure. Here we developed and evaluated various novel instrument designs for controlled and safe intraocular translocation of peripherally excised RPE grafts into the submacular space following subfoveal CNV excision. Methods: Four different novel translocation spatulas for intraocular use were developed and evaluated in an in vitro training kit for autologous RPE sheet translocation. RPE/Bruch’s membrane/choroid patches were obtained from human donor eyes. The two critical steps of transient firm adhesion of the patch without deformation on the bended end of the spatulas and subsequent subretinal release of the patch were recorded and compared between the different designs. Results: All spatulas allowed for sufficient transient attachment and movement of the RPE/choroid patches by manually controlled fluid suction via a small opening positioned at the basal transplant side. Release of the patch was achieved either by flushing of BSS through the same opening (#1), through six extra openings at the apical spatula margin and concurrent release of suction at the central hole (#2), a flat slide that could be moved anteriorly on the surface of the spatula to detach the patch from the suction hole (#3) or by irrigation through an anterior slit (#4). Release of the patch was hampered to various degrees using spatula designs with a nonmechanical detachment principle due to trapping of fibrous choroidal tissue components that were sucked into the openings. In contrast design #3 with a movable slide allowed for ready and atraumatic release. Conclusions:Improved designs of transplantation spatulas that combine holding and release function into a single instrument allow for efficient and controlled translocation of peripherally excised autologous RPE patches into the subretinal space. Their use facilitates the surgical procedure, minimizes trauma to the graft and therefore might result in better graft survival with vital RPE to sustain photoreceptor function in eyes following removal of subfoveal CNV.
Keywords: age-related macular degeneration • retinal pigment epithelium • transplantation