The Development of Biodegradable Intrascleral Implant for Slow Releasing of Triamcinolone Acetonide

PURPOSE: In order to treat inflammatory and proliferative disorders of the posterior segment of the eye, the authors evaluated the use of a biodegradable intrascleral implant for slow release of triamcinolone acetonide (TA). METHODS: The intrascleral implant (1 mm thick and 3 mm in diameter) was made of alginic acid and PLA (poly (D, L-lactide)) containing 4 mg of TA. In vitro release of TA was evaluated by HPLC. To evaluate in vivo release of TA, the implant was placed into a scleral pocket in 18 rabbit eyes and the concentrations of TA in the aqueous humor, vitreous, and retina-choroid-sclera were measured by HPLC at 1, 2, 4, 8, and 12 weeks after implantation. The toxicity and biocompatibility of the implant were evaluated by slit lamp examination, IOP, electroretinogram, and light microscopy. RESULTS: In vitro study demonstrated that the implant released TA in controlled manner for at least 8 months. The TA detected in the vitreous after 8 to 12 weeks and was not detected in retina-choroid-sclera at 8 weeks after implantation. The TA was not detected in aqueous humor. No significant toxicity to the retina was observed. CONCLUSIONS: These results suggest that the intrascleral implant of TA could be a promising system for the delivery of steroids to the posterior segment of eye in cases of inflammatory or proliferative disorders of posterior segment.

Clinical Experience with Medpor Implant Through Transconjunctival Incision in Blow-out Fractures

Medpor, the high density porous polyethylene, which permits rapid ingrowth of both soft tissues and vasculatures, is highly stable but somewhat flexible and is also easy to shape. So it has been often used for plastic and reconstructive surgeries including facial bone fractures, as well as orbital wall fractures. The authors investigated sex and age distribution, causes of injury, combined ocular injuries, and fracture sites of 45 blow-out fractures. And 27 orbital reconstructions was performed by using 0. 85mm thickness Medpor within 2 weeks after injury, if possible. During post-operative follow up, the preoperative diplopia was resolved or decreased in all cases, but the enophthalmos was not completely resolved. Much researches will be needed for choice of Medpor`s thickness or operation methods, and long term stability shoud be approved through further follow up.