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T. Ratanapakorn, P.A. A. Mello–Filho, R. Tano, N.R. F. Beeley, D. Guven, J. Wang, M. La Fontaine, E. de Juan, Jr, S.E. Varner; Helical Intravitreal Triamcinolone Implant: An Explantation Survival Study . Invest. Ophthalmol. Vis. Sci. 2005;46(13):484.
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Purpose: To evaluate outcomes of an explantation procedure for the helical intravitreal implant in rabbit eye. Methods: Thirteen rabbits received a helical intravitreal drug delivery implant OD. Eleven rabbits were followed for 6 weeks and 2 were followed for 6 months after implant. The implants were then removed and rabbits were followed clinically for 6 weeks. For explantation, a small conjunctival incision was made over the implant cap; the implant was grasped with surgical forceps or a custom surgical instrument and upward pressure was applied. Two wound closure techniques were used: 6 eyes were closed with a single scleral suture, while the scleral wound was left open in the remaining 7 eyes. All eyes received a conjunctival suture. Ocular examination, fundus photography, and ERG were performed before and after explantation. At the conclusion of the study, the globes were prepared for histologic study. Results: IOP and ERG after explantation were comparable between the 2 groups. Complete conjunctival healing was observed after both wound closure techniques. After explantation, vitreous hemorrhage was found in 6 rabbits, 2/6 (33.33%) from scleral sutured group and 4/7 (57.14%) from non–sutured group. In 2 rabbits of the non–sutured group, the vitreous hemorrhage obscured the view of the fundus. IOP dropped slightly post explantation in both groups. Average IOP before and 1 week after explantation were 17.33 and 13.61 mmHg in sutured group and 15.71 and 12.90 mmHg in non–sutured group, respectively. There were no signs of endophthalmitis, other infection or retinal detachment in the operated eyes. Preliminary histologic study showed established scleral wound healing in both groups by 6 weeks. Conclusions: Both wound closure techniques prevented infection and resulted in wound healing. In no case did implant removal result in retinal detachment. Immediate hypotony resulting from the removal of an implanted device may contribute to post operative vitreous hemorrhage. Suturing the wound with a single suture may reduce the rate of hemorrhage.
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