Abstract
Purpose: :
To describe a novel surgical technique and device in an in vivo porcine model for translocating a circular, autologous, Choroid-Bruchs membrane-Retinal pigment epithelium (CBR) graft of into the sub area centralis (subfoveal equivalent) space.
Methods: :
Sequential animal studies in 40 pigs, sus scrofa, were used to document key steps, using high-resolution image capture, endoscopy, and surgical animation to document the technique.The tissue support structure was designed using iterative methodology between a surgeon and mechanical engineers in the setting of technical, ex-vivo, and in vivo surgical sessions. The tissue support structure is made of nitinol foil (25 microns thick) in a hinged double-O-ring configuration. Key surgical steps for the in vivo porcine model include: 1) pars plana vitrectomy, 2) pars plana lensectomy, 3) peripheral retinal detachment induction and excision (autograft donor site), 4) millipulse laser delineation of the CBR donor site, 5) tissue clamping with the device using radiofrequency energy, 6) excision of donor CBR tissue, 7) retinal detachment of the area centralis, 8) insertion of the device with supported, polarized autologous CBR tissue into the sub-area centralis or porcine sub-foveal equivalent.
Results: :
We have successfully performed all steps and stages of this procedure, and refined the methodology in seven pigs. The tissue support structure has the advantages of shape-memory, thin design, tissue compatibility, and potential for graft vascularization. Three pigs were survived, with one animal studied six weeks post-translocation. The animal model combined with a metal device limit functional studies and histopathology of donor tissue respectively.
Conclusions: :
This novel methodology for translocating autologous peripheral CBR tissue into the subfoveal space may address advanced macular degenerative conditions, yet warrants further safety studies in a primate model prior to introduction into human studies.
Keywords: vitreoretinal surgery • age-related macular degeneration • choroid