| Purpose In order to improve the long-term effect of anti-glaucoma filtering operation and keep the filtering pathway to be opened, we designed an "Artificial Trabecular Frame" made of PMMA. It can be implanted under the scleral flap in operation, which can be called "Filtering Pathway Plasty". The purpose of the research is to testify its feasibility, security and effectivity. Material and Method 1. Experimental study of trabeculectomy andfiltering pathway plasty on normal sheep eyes: Sixteen of normal sheep were performed operation. The right or left eyes (random) served as experimental group and were performed trabeculectomy and filtering pathway plasty, an artificial trabecular frame was implanted under the scleral flap; the another eyes served as control group and were performed traditional trabeculectomy. At the 1st, 2nd and 3rd day, 1st, 2nd, 3rd and 4th week, 2nd, 3rd and 6th month after surgery, we measured intraocular pressure (IOP) with Schiotz tonometer and observed morphology of anterior segment with handle slit lamp. We performed UBM examination at 1st week, 1st month and 3rd month. These sheep were killed at the 1st, 2nd and 4th week, 3rd and 6th month after surgery from the last number separately, and the pathological examination of these eyes were performed. 2. Study on the cytotoxicity test, acute toxiciy test,subcutaneous irritant test and subscleral flap test of the PMMA frame. 3. We performed trabeculectomy and filtering pathway plasty on 3 voluntary patients with obstinate, recrudescent glaucoma and made a 2-year follow-up survey. Result 1. From the 1st day after surgery, the decreased range of IOP in3experimental group was larger than that of control group. The most obvious difference occured at the 4th week after surgery, the average of decreased IOP in experimental group was 4.13 mmHg while the value of control group was 0.52mmHg, P=0.000004. After the peak, the difference between two groups became smaller and smaller. The IOP of control group restored to the pre-operation value at the end of 4th week after surgery, but the IOP of experimental group didn't restored until the end of the 3rd month after surgery. The morphology of filtering blebs: The UBM of experimental group shows high filtering bleb and big liquid space at the 1st week after surgery, whereas that of control group is flat. At the end of the 1st month after surgery, UBM of experimental group shows high filtering bleb, strong echo of the frame, the filtering bleb at surface layer tissue of the frame and big liquid space under the frame, but the filtering bleb of control group is low or flat. At the end of the 3rd month after operation, the filtering bleb of experimental groupe still exists, but that of control group closed. The pathological result accords with UBM: The filtering pathway of control group heals in a normal way, the scleral flap adhered loosely at the end of the 1st week after operation and almost fibroblastic proliferation at 4 week after surgery . The healing progress of filtering pathway of experimental group was delayed. The liquid space exists at 4 weeks after surgery, and it lasts until the end of the 3rd month after operation, then disappeared at the end of the 6th month after surgery and the filtering pathway adhered thoroughly. The tissue compliance is good and no exclusion occurred. No toxic or adverse effects were observed in the following year after operatioa 2. The tests were performed under the supervision of China Drugs Administration, and the outcomes of the 4 tests agree to the national criteria. 3. Clinical study on 3 patients showed good IOP decreasing effect. Conclusion This frame provides a space to prevent adhesion of scleral flapafter operation. This article is the research results in vivo on normal sheep eyes, biocompatibility and 2-year follow-up survey on 3 obstinate, recrudescent glaucoma patients after operation. Considering the difference of healing ability between human and animal, the "plastic effect" on human should be good. Moreover, it can be us... |
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