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Michael T. Trese, Tetsu Asami; A Quadraport Needle Gives Better Spread of Drug During Intravitreous Injection. Invest. Ophthalmol. Vis. Sci. 2011;52(14):1703.
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Enzymes (microplasmin and plasmin) to manipulate the vitreoretinal juncture (VRJ) have been shown to be more effective at the site of initial injection. It also has been shown that microplasmin is inactivated by binding to substrate and is autolytic. To try and achieve maximum enzymatic effect we developed a new quadraport needle to hopefully increase the area of initial injection
The tip of this 30 gauge quadraport needle is cecal and has four tiny holes on four sides so that fluid comes out in four directions in an attempt to envelop a larger area than the standard 30 gauge needle. To test its effect on spreading fluid, we injected diluted India ink into rabbit mid-vitreous with the quadraport needle and compared the spreading pattern of the ink with that of the injection with conventional 30 gauge needle. We then tested another group of rabbits by injecting 125µg of microplasmin into the mid-vitreous with the quadraport needle and 30 gauge standard needle. One week after the injection, they were sacrificed and the eyes were fixed and observed by scanning electron microscopy.
The injection of India ink showed that the ink injected with a standard 30 gauge needle just accumulated around the tip of the needle, whereas the ink injected with the quadraport needle spread more quickly and in a wider area than the 30 gauge standard needle. The scanning electron micrographs of microplasmin injected eyes revealed that the surface of the retina injected with the ½-inch quadraport needle showed no residual material on the ILM of the retina when compared to the ½-inch 30 gauge standard needle at as high as 500X magnification.
When microplasmin enzyme is injected using the quadraport needle, it can spread injected material over a wider area and gives a cleaner retinal surface than the conventional 30 gauge needle.
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