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D. Ivastinovic, G. Langmann, W. Nemetz, R. Hornig, A. Meyer, M. Velikay–Parel; The Pig As An Animal Model For Retinal Chip Implantation . Invest. Ophthalmol. Vis. Sci. 2006;47(13):3164.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate the influence of various procedures in posterior segment surgery for later epiretinal prosthesis implantation.
12 domestic pigs were operated and divided in 4 groups of 3 animals. In group 1 we performed (a) dispase assisted vitrectomy with lensectomy and (b) retinal tack insertion. In group 2 the same procedure was done without lensectomy. In group 3 (a) dispase assisted vitrectomy, (b) 4 mm sclerotomy and (c) retinal tack insertion, and in group 4 (a) dispase assisted vitrectomy, (b) 4 mm sclerotomy with partially intraocular placement of a polyimide film through the wound were performed. Dispase was used to ensure the posterior vitreous detachment. The animals were observed for 4 weeks. In a second series we operated 15 Göttinger minipigs to establish the operation method for the new epiretinal implant. Lensectomy, vitrectomy, tack insertion, scleral pocket and 4 mm sclerotomy were performed and a polyimide strip was inserted through the sclerotomy covered with a sclera flap. The polyimide strip was fixated onto the retina by the nail. The distal end of the strip was attached to the calotte, which was sutured onto the sclera.
Vitrectomy with lensectomy and tack fixation caused membrane formation in the pupillary area and strand formation to the tack, whereas this could not be observed in the group without lensectomy. The placement of the tack caused minor choroidal and retinal bleeding in 10% of our animals. The 4 mm sclerotomy caused local scar tissue. Eyes with the 4 mm sclerotomy with the inserted polyimide strip maintained intraocular pressure; the scar tissue formation was slightly more extended. No retinal detachment could be observed. In the second series the operation procedures was established without retinal damage or excessive bleeding. Wound closure was completed and the eyes maintained the intraocular pressure.
Lens sparing vitrectomy well tolerated in pigs. The tack can be set without prior pexy of the retina. Eyes with a polyimide strip placed through the sclerotomy maintained the intraocular pressure. The first part of the study demonstrates that surgical procedures of that extend is tolerated by pig’s eye in a longer observation period. Further more the second part of the study proved that the new operation procedure is feasible in pigs’ eyes.
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