| Glaucoma is a group of eye disorders associated with intraocular pressure (IOP) that can result in progressive optic nerve atrophy and visual field damage. Multicenter study showed that decreasing the IOP is the only effective treatment for glaucoma in current clinical practice. There are many ways to decrease the IOP at present, such as anti-glaucoma medicines, laser, physical therapy and surgery. These methods can be used alone or in combination according to different types of glaucoma and different situations of patients. Although increasing evidence suggested that medicines can decreasing the IOP efficaciously for glaucoma at the early stage but they are not effective for assisting the majority of patients with reaching the "target IOP" because their glaucoma have already developed to the middle or late stage when they come to hospitals for treatments due to the strong occultness of glaucoma. Therefore, the surgery is still an important treatment for glaucoma, especially in developing countries. Although trabeculectomy is still the most common surgery used in current clinical practice and both its effectiveness and safety have been improved consistently after more than 40 years, this surgery still has several disadvantages including high requirements of surgery skills, large intervention in eyeball, and more complications, etc. Faced with these disadvantages, new types of surgery are developed and considered, like the implantation of Ex-PRESS glaucoma drainage device. It was developed and introduced recently with innovation in its design and comparative advantage in clinical practice, however, it has not been widely used in China yet.Both the mechanism of decreasing IOP and patients’postoperative appearance of Ex-PRESS glaucoma drainage device implantation are similar to those of trabeculectomy, but the implantation has the following different characteristics compared with trabeculectomy. (1) Trabeculectomy needs to remove part of the trabecular tissue and corresponding parts of the iris root tissue. Both iris blood supply and iris nerve are so rich that can lead to bleeding, pulling pain, etc. If the root cutting hole or palpebral fissure of patients is too large that eyelid cannot cover, it is easy to appear double vision, and then causing monocular diplopia in patients. The Ex-PRESS glaucoma drainage device implantation does not need to remove iris and trabecular tissue, thus, the risk of intraoperative bleeding and postoperative infection will be greatly reduced. In conclusion, The Ex-PRESS glaucoma drainage device implantation is more suitable for the patient with coagulation defects, poor resistance or large palpebral fissure. (2) Because the surgical technique about Ex-PRESS glaucoma drainage device implantation is more simple and fast with less wound and no damage to intraocular tissues, the anterior chamber can maintain well during operation. Thus it is more suitable for glaucoma patients who have combination with intraocular hemorrhage, the risk of retinal detachment or large injury in ocular surface tissue after the operation. (3) Foreign researches suggested that Ex-PRESS glaucoma drainage device implantation and trabeculectomy provided similar IOP control, but Ex-PRESS was more likely to have less effect on the vision and less complications. Long term follow-up studies showed that the Ex-PRESS glaucoma drainage device implantation can reducing dependency on anti-glaucoma medicines after surgery compared with trabeculectomy. (4) Different models of Ex-PRESS glaucoma drainage device have different internal axial lumen that can limit the aqueous humor outside flow rate differently, therefore it can help patients to achieve personalized "target IOP" eventually. Based on these advantages, the Ex-PRESS glaucoma drainage device implantation will play an increasingly important role on treatment for open-angle glaucoma in China.Currently, there are 3 different models of the Ex-PRESS miniature glaucoma drainage device are commercially available:the P-50, R-50 and P-200. Type of P-50 and P-200 are formally applied in China from March,2012. The outer diameter of both these two models is 0.4 mm, equivalent to a 26-G needle. The main difference of these two models is that the P-200 model has an internal axial lumen of 200μm, whereas the P-50 model is 50μm. Both the P-50 and P-200 models are 2.64 mm in length. According to the Stephan Estermann’s report, when the pressure was at 5,10, 15,20,and 25 mmHg the flow rate of P-50 models were (97 ± 4.3), (186 ± 10.8), (274 ± 6.8), (327 ± 32.8) and (410 ±26.1) μL/min respectively, whereas the flow rate of P-200 models were (664 ± 25.2), (1180 ± 24.7), (1575 ± 21.6), (1928±28.0) and (2241 ± 27.5) μL/min respectively. The resistance values of P-50 models were (0.051 ± 0.002), (0.053 ± 0.003), (0.054 ± 0.001), (0.061 ± 0.007) and (0.060 ± 0.001) mmHg/μL/min respectively, while at the same pressure, the resistance values of P-200 models were (0.007 ± 0.0003), (0.008 ± 0.0001), (0.009 ± 0.0001), (0.010 ± 0.0001) and (0.011 ± 0.0001) mmHg/μL/min respectively. So the P-200 model had a 5-6 times higher flow rate than the P-50 model, but P-50 model showed 6-7 resistance to flow compared with the P-200 model. Because of the difference of flow rate and flow resistance in P-50 and P-200 models, the results of the two surgeries and surgical complications such as hypotony, shallow anterior chamber and choroidal detachment should be different. So far, neither the manufacturers nor the literature reviews has provided any guidelines for the clinical use of the two different models.Patients should choose what type of drainage device in their situations which is related to the efficacy and safety of patients undergoing surgery are need to be solved urgently. In order to provide an evidence for choosing the two models, after completing the preliminary validation of clinical efficacy and safety about Ex-PRESS miniature glaucoma drainage device implantation and trabeculectomy in Chinese patients with open angle glaucoma, a prospective randomized study about effectiveness and safety of P-50 and P-200 models Ex-PRESS glaucoma drainage device implantation for open angle glaucoma was designed. Eighty eyes of 69 patients with various types of open angle glaucoma were included and randomized into 2 groups according to randomized digital table. The P-50 model Ex-PRESS glaucoma drainage device was implanted in 40 eyes in the P-50 group, and the P-200 model was implanted in another 40 eyes in the patients of the P-200 group. Related indicators about early and long term safety and effectiveness of P-50 and P-200 models Ex-PRESS glaucoma drainage device implantation for open angle glaucoma were comparative analyzed. The main research contents and results were summarized as follows.Part One Comparison of therapeutic effect in early stage between Ex-PRESS glaucoma drainage device implantation and trabeculectomy in open angle glaucoma PurposeTo compare the therapeutic effect and security in early stage between Ex-PRESS glaucoma drainage device implantation and trabeculectomy in open angle glaucoma (OAG).MethodsThe medical records of 57 cases with OAG treated with Ex-PRESS (P-50) implantation (29 cases 33 eyes) or trabeculectomy (28 cases 36 eyes) in our hospital during the same period were retrospectively analyzed, and the disease composition, theoretical days of hospitalization, incidences of complications and changes in visual acuity and intraocular pressure between admission and discharge were statistically evaluated by Statistics.ResultsThe rate of males and females in Ex-PRESS and trabeculectomy group were 1.75:1 and 1.77:1 (P>0.05), with an average age of (38.21±21.13) and (41.50± 20.46) years old, (P>0.05). The disease composition of the two groups was significantly different (P<0.05) with less pure primary open angle glaucoma cases in Ex-PRESS group. Theoretical days of hospitalization of Ex-PRESS and trabeculectomy group were (3.12±0.06) and (4.47±0.28) days respectively, showing significant decreases in the Ex-PRESS group, (P<0.05).The rate of incidences of complication was significantly (P<0.05) lower in Ex-PRESS group (9.09%) than that in trabeculectomy group (27.78%). The best corrected visual acuity (BCVA) recovery time in the Ex-PRESS group was (3.43±0.21) days and those in the trabeculectomy group was (5.07±2.19) days, showing significant decreases in the Ex-PRESS group, (P<0.05). Changes in IOP between admission and discharge of the two groups were (22.05±13.20) and (21.11±13.58) mmHg and had no significant difference (P>0.05).ConclusionsAlthough trabeculectomy and Ex-PRESS implantation provided a similar IOP control effect in early stage, but Ex-PRESS implantation showed a lot of advantages over trabeculectomy in this study such as lower rate of complications, shorter theoretical days of hospitalization especially much smaller influence on visual acuity. In addition to pure POAG, Ex-PRESS implantation may be especially suit for almost all kinds of secondary OAG and POAG complicated with relating risk factors.Part Two Early effectiveness of P-50 and P-200 models Ex-PRESS glaucoma drainage device implantation for open angle glaucoma:a prospective randomized controlled studyPurposesThis study was to compare the therapeutic efficacy and security of Ex-PRESS implantation between P-50 and P-200 model of Ex-PRESS glaucoma drainage devices for open angle glaucoma.MethodsA prospective randomized controlled study was designed, and written informed consent was obtained from each patient prior to entering in the cohort. Eighty eyes of 69 patients with various types of open angle glaucoma were included from March 2012 to April 2013 in Wuhan General Hospital of Guangzhou Military Command. The patients were randomized into 2 groups according to randomized digital table. The P-50 model Ex-PRESS glaucoma drainage device was implanted in 40 eyes of 35 patients in the P-50 group, and P-200 model was implanted in 40 eyes of 34 patients in the patients of the P-200 group. The disease composition, best corrected visual acuity recovery time, theoretical hospitalization days, lowing intraocular pressure range and postoperative complications were compared between these two groups.ResultsThe average lowing-IOP ranges of the P-50 group and P-200 group were (21.69±12.50) and (24.20±13.17) mmHg respectively, with insignificant difference between them (t=-1.201, P>0.05). The theoretical hospitalization days and BCVA recovery time in the of P-50 group were (3.24±0.50) and (2.85±0.95) days, and those in the P-200 group were (4.90±0.81) and (3.40±0.96) days, showing significant decreases in the P-50 type group (t=-6.444, P<0.01;t=-2.584,P<0.05). The incidence of postoperative complications were 6.06% and 25.00% in P-50 group and P-200group respectively, with significant difference between the two groups (χ2=9.800, P<0.05).ConclusionsAlthough P-50 and P-200 models Ex-PRESS implantation provide a similar effect in lowing IOP, P-50 model Ex-PRESS implantation can restore BCVA more rapidly and lessen complications in comparison with P-200 model Ex-PRESS implantation.Part Three Effectiveness and safety of P-50 and P-200 models Ex-PRESS glaucoma drainage device implantation for open angle glaucoma:a prospective randomized controlled study, with 2 years followed upObjectiveThis study was to compare the therapeutic efficacy and security of Ex-PRESS implantation between P-50 and P-200 model of Ex-PRESS glaucoma drainage devices for open angle glaucoma with 2 years followed up.MethodsThere were 36 and 34 eyes in P-50 and P-200 group respectively completed 2 years of follow-up respectively. According to the study protocol about early study of P-50 and P-200models Ex-PRESS glaucoma drainage device implantation for open angle glaucoma, the research objects in the two groups were followed up for 2 years. The IOP and numbers of anti-glaucoma medications at postoperative 1 week,1 month,3 months,6 months,12 months,18 months and 2 years; operation success rate at postoperative 3 months,6 months,12 months,18 months and 2 years and the classification filtering bleb morphology at postoperative 1 year and 2 years were compared between these two groups.ResultsThe IOP at postoperative 1 week,1 month,3 months,6 months,12 months,18 months showed no significant difference between the two groups, (P>0.05). However, when followed up to 2 years, the IOP in P-50 group (16.89±3.18) mmHg was significantly higher than P-200 group (14.85±5.26) mmHg, (P<0.05). The numbers of anti-glaucoma medications at postoperative 1 week,1 month,3 months,6 months, 12 months showed no significant difference between the two groups, (P>0.05). However, when followed to postoperative 18 months and 2 years, the numbers of anti-glaucoma medications in P-50 group were significantly higher than P-200 group(P<0.05). Although the numbers of vascularization filtering bleb at various levels and different heights filtering bleb eyes showed no significant difference between the two groups at postoperative 1 year or 2 years (P>0.05), but different range of filtering bleb eyes at postoperative 1 year or 2 years had a significant difference between the two groups with a bigger range filtering bleb in P-200 group than P-50 group (P<0.05).The absolutely success rate at postoperative 1 week,1 month,3 months,6 months,12 months and the total success rate at postoperative 1 week,1 month,3 months,6 months,12 months,18 months and 2 years showed no significant difference between the two groups, (P>0.05). However the absolutely success rate at postoperative 18 months and 2 years had a significant difference between the two groups with a higher in P-200 group (77.14% and 76.47% respectively) than P-50 group (54.05% and 52.78% respectively), (P<0.05).ConclusionsWhen followed up to 2 years, P-200 model Ex-PRESS drainage device implantation is seemed to more ideal IOP contro1,the less used of numbers of anti-glaucoma medications, the bigger range of filtering bleb and the higher of absolutely success rate than P-50 model Ex-PRESS implantation. |
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