3-year results after XEN-45- stent implantation

3-year results after XEN-45- stent implantation | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article 3-year results after XEN-45- stent implantation Christian Karl Brinkmann, Ulrike Holland, Ranny Abou Assaf This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8618195/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose Currently, few studies are available on long-term outcomes after XEN microstent implantation beyond three years. This article is to collect 3-year outcomes regarding the efficacy and safety of the XEN-45 stent. Methods Data were collected from 149 eyes undergoing XEN(Abbvie, Germany) implantation at our hospital from December 2013 to November 2018. As criteria for efficacy, we use intraocular pressure (IOP), number of pressure-lowering medications, and need for reoperation. As criteria for safety, we list intraoperative complications. Results The mean patient age at surgery was 72.44 ± 7.99 years (range 54 to 85 years, n=149). 56% of the patients were female. 15% of these 149 eyes (n=23) required further glaucoma surgery. Forty eyes of 37 patients came to the clinic for follow-up at recall. The median follow-up time was 45.92 months (3.77 years). Approximately 92% (n=37) of eyes without follow-up surgery (n=40) achieved an IOP of ≤ 21 mmHg with or without additional medications, approximately 85% (n=34) achieved an IOP of ≤ 18 mmHg, and approximately 72% (n=29) achieved an IOP of ≤ 15 mmHg. Intraoperative complications occurred in 20% of eyes (n=149). The majority of these were minor intracameral hemorrhages at 13%. More severe bleeding occurred in only 3 (2%) eyes No postoperative hemorrhage requiring anterior chamber irrigation occurred in any eye. Conclusion The XEN microstent achieves a sufficient pressure-lowering effect over 3 years and is characterized by high intraoperative safety. The study is registered in the German Register of Clinical Studies (DRKS00023619; 19th November 2020). glaucoma surgery microstent Intraocular pressure drop therapy Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Background Since December 2013, the XEN45 microstent has been used in surgical glaucoma treatment at the Department of Ophthalmology of the Dietrich-Bonhoeffer-Klinikum Neubrandenburg. So far, follow-up data after XEN microstent implantation up to 2 years have been published [ 1 , 2 , 3 ]. Long-term data beyond this are currently being increasingly published [ 4 ]. The purpose of this study is to collect long-term outcomes after XEN microstent implantation beyond 3 years. The long-term results are of considerable importance for the evaluation and positioning of the XEN stent procedure in surgical glaucoma therapy. The aim of this study is to collect data after an average of 3 years. It will be investigated to what extent the study results of multicenter studies can be transferred to a monoclinical setting. The question is to determine the effect of XEN microstent implantation on intraocular pressure (IOP) and the number of necessary antiglaucomatous therapies as well as the safety of the procedure based on the occurred intra- and postoperative complications. Patients and Method All patients after implantation of a XEN microstent in at least one eye from December 2013 until the end of 2018 were scheduled for potential participation in the study. Patients of whom we already had the long-term data because they had been in the eye clinic for an examination in the meantime anyway were not revisited. The data were taken from the existing medical record and analyzed. The indication for surgery arose in all patients during the glaucoma consultation at the eye clinic. Patients with a history of suprachoroidal CyPass stent implantation and an indication for follow-up XEN stent implantation were included. Excluded were eyes in which, apart from suprachoroidal CyPass stent implantation, a fistulous glaucoma surgery such as trabeculectomy or goniotrepanation was performed prior to XEN stent implantation. 149 eyes were eligible for the study, of which 23 eyes had already undergone a second glaucoma pressure-lowering procedure at the time of the study. We defined these as treatment failures and did not invite them for follow-up. Primary endpoints were to determine the effect of XEN 45 microstent implantation on intraocular pressure, on the number of necessary antiglaucomatous agents applied, progression of glaucoma in terms of visual field deterioration and progression of glaucomatous optic disc changes, and loss of endothelial cells. Secondary endpoints were the safety of the procedure based on the intraoperative and postoperative complications encountered, the development of the stent-associated subconjunctival oozing cushion, and the clinical identification of stent failures. The analyzed data presented below are from 40 of 126 eyes (excluding failures). 86 eyes (74 patients) could not participate in the study for various reasons. The statistical evaluation of the collected data was carried out with the program STATISTICA, version 13 (StatSoft, Hamburg, Germany) with T-Test, Wilcoxon and Mann Whitney U analysis. Results At the time of the final examination, 23 eyes had already been defined as treatment failures (15%, n = 149 eyes). The other patients were recalled to the clinic to participate in the study. 86 eyes did not participate in the study (58%, n = 149 eyes). Of these, 28 (18%) patients/eyes had declined study participation, 24 (16%) patients had already died, 5 (4%) patients had moved too far, 17 patients were not transportable because of illness (11%), and 12 (8%) patients could not be reached. Of a total of 149 patient eyes invited for examination, 40 eyes of 37 patients [ Tab.] were followed up (27%, n = 149 eyes). Table 1 Demographic data of 40 patients Demography n = 40 Mean (SD); Range Age at surgery (years) 71.58 (7.14); 54–84 Age at follow-up (years) 75.63 (7.09); 48–90 Follow-up duration (years) 4.05 (1.33) 2.91–3.98 Median 3.77 Gender Male /Female 18 (45%)/ 22 (55%) Eye OD / OS 22 (55%) / 18 (45%) Intraocular pressure regulation Preoperative intraocular pressure averaged 21.65 ± 8.93 mmHg (median = 20.0 mmHg; range 11–54 mmHg; n = 40). During follow-up, intraocular pressure was 15.15 ± 4.61 mmHg (median = 15.0 mmHg; range 8–25 mmHg; n = 19; missing data: n = 21), 15.06 ± 4.45 mmHg (median = 15.0 mmHg; range 7–25 mmHg; n = 17; missing data n = 23), 12.05 ± 2.76 mmHg (median = 12.0 mmHg; range 8–19 mmHg; n = 20; missing data: n = 20), and 13.00 ± 2.40 mmHg (median = 13.0 mmHg; range 10–18 mmHg; n = 18; missing data: n = 22), respectively. Figure 1 Boxplot representation of the course of intraocular pressure postoperatively. The baseline median intraocular pressure is 20 mmHg with a postoperative decrease in the first year and relatively stable course over 3 years At the final examination, intraocular pressure averaged 14.40 ± 4.96 mmHg (median = 14.0 mmHg; range 7–35 Fig 2. Percentage representation of the achieved pressure thresholds over the course of the 3 years independent of the supplementary medication mmHg; n = 40). The mean pressure reduction compared with baseline pressure was 7.18 ± 10.29 mmHg (range of pressure difference from baseline pressure − 17 to + 40 mmHg, n = 40 [Fig. 3 ]). The reduction in pressure at final examination, or the difference between baseline pressure and final findings is statistically significant (T-test; difference = 7.18 mmHg; p < 0.001; n = 40) (Wilcoxon test; p < 0.001; n = 40). 37 eyes (92%) achieved an IOP of ≤ 21 mmHg after 3 years with or without additional drug pressure reduction, of which 21 eyes were drug-free. An intraocular pressure of ≤ 18 mmHg was achieved by 34 eyes (85%), of which 19 eyes were not using medication. An intraocular pressure of ≤ 15 mmHg was reached by 29 eyes (72%), of which 16 eyes were without pressure-lowering medication (Figs. 2 and 3 ). The correlation between the number of preoperative pressure-lowering medication and the intraocular pressure at the final examination is statistically significant (Spearman; R=-0.321; p = 0.044; n = 40). The correlation between patient age at surgery and intraocular pressure at final examination is not statistically correlated (Spearman; R=-0.2297, p = 0.154; n = 40). The naïve eyes showed no significant difference in intraocular pressure at the final examination compared to the CyPass-preoperated eyes (naïve vs. preoperated: Mann-Whitney U (MWU) Test; Z=-1.021; p = 0.307; n = 40 [20 preoperated; 20 naive]). Drug Therapy The mean number of pressure-lowering agents preoperatively was 1.83 ± 1.22 agents (median = 2.0; range 0–4 agents, n = 40). At 3, 6, 12, and 24 months, the mean was 0.26 ± 0.78 (median = 0.0; range 0–3, n = 19; missing data: n = 21), 0.29 ± 0.96 (median = 0.0; range 0–4, n = 17; missing data: n = 23), 0.35 ± 0.85 (median = 0.0; range 0–3, n = 20; missing data: n = 20), and 0.61 ± 1.21 (median = 0.0; range 0–4, n = 18; missing data: n = 22). At the final examination, the mean number of pressure-lowering medications was 1.03 ± 1.33 (median = 0.0; range 0–4, n = 40 [Fig. 4 ]). Here, the difference from baseline findings is highly statistically significant. (T-test; p < 0.001; n = 40) (Wilcoxon test; p = 0.002; n = 40). Course of visual acuity Visual acuity was documented and evaluated as a decimal number. Mean baseline visual acuity was 0.72 ± 0.27 (median = 0.8; range 0.10–1.00; n = 40). At 3, 6, 12, and 24 months, the mean was 0.76 ± 0.22 (median = 0.8; range 0.20–1.00; n = 19; missing data: n = 21), 0.79 ± 0.19 (median = 0.7; range 0.40–1.00; n = 17; missing data: n = 23), 0.79 ± 0.25 (median = 0.79; range 0.10–1.00; n = 20; missing data: n = 20), and 0.68 ± 0.25 (median = 0.8; range 0.10–1.00; n = 18; missing data: n = 22). At the final examination, the mean value was 0.68 (M = 0.67) with a range of 0.10–1.25; n = 40. Visual acuity at the final examination was not significantly different from preoperative visual acuity (Wilcoxon test; p = 0.322; n = 40) (T-test; p = 0.328; n = 40). Visual field Preoperatively, mean deviation averaged − 11.19 ± 7.70 dB (median=-10.30; range − 30.27 to + 2.61 dB; n = 40). At 3, 6, 12, and 24 months, the MD averaged − 12.69 ± 5.54 dB (median=-11.53; range − 20.26 to -2.45 dB; n = 10; missing data: n = 30), -8.05 ± 6.84 dB (median=-6.14; range − 20.17 to + 0.67 dB; n = 14; missing data: n = 26), -10.40 ± 8.02 dB (median=-8.17; range − 26.69 to + 0.31 dB; n = 12; missing data: n = 28), and − 12.55 ± 8.28 dB (median=-12.06; range − 30.24 to + 0.44 dB; n = 13; missing data: n = 27). At the final examination, MD averaged − 13.27 ± 9.04 dB (median=-11.96; range − 30.24 to + 1.31 dB; n = 36; missing data: n = 4). Visual field testing with the Humphrey device was not possible in four patients. The difference between the preoperative MD and the MD at the final examination was on average − 1.85 ± 6.44 dB. This difference is statistically significant (T-test; p = 0.0318; n = 35) (Wilcoxon test; p = 0.004; n = 35). Thirteen of 35 follow-up eyes (37%) showed MD reduction of more than 3 dB after an average of 3.77 years. A progression of more than 5 dB could be detected in only 7 eyes (20%) (n = 35, missing data: n = 5). On average, there was a change in MD of -1.68 ± 4.38 dB/year in the eyes examined postoperatively (range − 12.95 to + 12.55 dB; n = 35). The number of visual field points in the central 5-degree visual field with a sensitivity ≤ 10 dB averaged 0.56 ± 1.01 points preoperatively (range, 0–4 points; n = 40). At 3, 6, 12, and 24 months, this number averaged 0.50 ± 0.92 points (range 0–3 points; n = 10; missing data: n = 30), 0.29 ± 0.59 points (range 0–2 points; n = 14; missing data: n = 26), 0.83 ± 1.28 points (range 0–4 points; n = 12; missing data: n = 28), and 0.62 ± 1.15 points (range 0–4 points; n = 13; missing data: n = 27), respectively. At the final examination, this number averaged 0.89 ± 1.25 points (range, 0–4 points; n = 35; missing data: n = 5). At five patients, visual field testing with the Humphrey device was not possible due to limited visual acuity or poor cooperation. The reduction in the number of central visual field defects was not statistically significant compared to baseline findings in the T-test (T-test; p = 0.216; n = 35). In contrast, the Wilcoxon test showed significance (Wilcoxon test; p = 0.012; n = 35). The pattern standard deviation (PSD) averaged 6.14 ± 3.41 dB preoperatively (M = 5.88; range 1.47–14.30 dB; n = 40). At 3, 6, 12, and 24 months, this value was 7.58 ± 2.60 dB (M = 8.04; range, 2.38–10.59 dB; n = 10; missing data: n = 30), 5.95 ± 3.73 dB (M = 4.21; range, 1.33–1.89 dB; n = 14; missing data: n = 26), 6.35 ± 2.91 dB (M = 6.41; range, 1.49–1.75 dB; n = 12; missing data: n = 28), and 6.19 ± 3.46 dB (M = 6.49; range, 1.44–13.00 dB; n = 38; missing data: n = 37) and 5.79 ± 4.03 dB (range, 1.39–15.90 dB; n = 14; missing data: n = 26). At the final examination, the PSD value averaged 6.86 ± 3.69 dB (M = 6.91; range, 1.40–14.26 dB; n = 35; missing data: n = 5). Optic disc morphology HRT II (Heidelberg Retinal Tomography) The average rim area preoperatively was 1.12 ± 0.43 mm² (range 0.35–1.98 mm²; M = 1.10 mm²; n = 39; missing data: n = 1). After 3, 6, 12, and 24 months, the rim area averaged 1.12 ± 0.10 mm² (range 0.99–1.23 mm²; M = 1.13 mm²; n = 4; missing data; n = 36), 1.07 ± 0.40 mm² (range 0.39, − 1.92 mm²; M = 1.14 mm²; n = 12; missing data: n = 28), 1.00 ± 0.33 mm² (span 0.45–1.56 mm²; M = 1.02 mm²; n = 13; missing data: n = 7), and 1.20 ± 0.65 mm² (span 0.12–2.47 mm²; M = 1.10 mm²; n = 13; missing data: n = 27). At the final examination, the rim area averaged 1.15 ± 0.55 mm² (range 0.05–2.47 mm²; M = 1.05mm²; n = 37; missing data: n = 3 eyes). In three patients no HRT measurement was possible due to lack of cooperation of patients. The difference between the preoperative findings and the findings at the final examination was not statistically significant (T-test: p = 0.774; Wilcoxon test; p = 0.968; n = 37). Optic disc morphology by nerve fiber OCT Nerve fiber evaluation is performed by the number of damaged segments and the extent of damage of each segment. There are 12 segments to be evaluated in each measurement. The healthy segments (shown in green) are classified as 0 points, the moderately damaged segments (shown in yellow) are classified as 1 point, and the markedly damaged segments in red are classified as 2 points. The total number of points is summed The mean score of optic disc morphology by RNFL-OCT was 8.70 ± 6.16 preoperatively (range, 0–22; M = 8.50; n = 30; missing data: n = 10). At the final examination, this value was 8.56 ± 4.49 (range 0–16; M = 10.00; n = 27; missing data: n = 13). This difference tends to show an improvement and excludes a worsening of findings on nerve fiber OCT. The difference between baseline and final findings is not statistically significant (T-test; p = 0.263; n = 27) (Wilcoxon test; p = 0.177; n = 27). Filtering blebs morphology Three months postoperatively, all eyes showed a slightly prominent filtering bleb (100%; n = 10; missing data = 30). At 6, 12, and 24 months, a filtering bleb was presentable in 13 (93%; n = 14; missing data = 26), 17 (100%, n = 17, missing data = 23), and 12 (86%; n = 14; missing data = 26), respectively. At the final examination, 36 of 40 eyes examined had a filtering bleb (90%; n = 40;), and the filtering bleb was still prominent in 7 of these 36 eyes. Intraoperative complications In 119 (80%) of 149 eyes, no intraoperative complications were documented based on the surgical reports. In 19 eyes (13%) minor bleeding (reflux hemorrhage) occurred. In three surgical reports (2%) severe intraoperative bleeding was described, which required further measures. In each case, the anterior chamber was filled with viscoelastic until hemostasis occurred. The blood was aspirated together with the viscoelastic at the end of the operation without any problems. In two operations, increased resistance occurred during implantation of the stent, which could be overcome with a second approach. In one surgery, intraoperative iris contact, complication of unstable guidewire, pain, and shallow anterior chamber occurred. In one eye, conjunctival perforation occurred through the tip of the implant. The conjunctival perforation site was re-injected with xylocitin so that it closed completely, the implant remained subconjunctival without the need for suturing. An only mild anterior chamber hemorrhage during aspiration of the healon could be completely removed from the anterior chamber (Fig. 5 ). [32 of 149 eyes were operated combined with phacoemulsification and posterior chamber lens implantation. 2 eyes showed hemorrhages in the anterior chamber, in one eye the stent had to be repositioned. Within the first week, cells were documented for 4 eyes and blood cells for 7 eyes. Four eyes developed fibrin in the anterior chamber] Early postoperative complications While the patient was still in hospital, the anterior segment of the eye was examined clinically every day for 3 to 4 days and any abnormalities were documented. 78 (52%) of 149 eyes showed no complications within the first 4 days. 12 (8%) of 149 eyes showed anterior chamber cells in the early postoperative course, 41 eyes (27.5%) showed blood cells, and 8 eyes (5.5%) showed fibrin reactions (of these, five eyes had been operated on combined with phacoemulsification and posterior chamber lens implantation; the fibrin reaction here cannot be clearly attributed to the stent implantation). Transient hyposphagma was seen in 11 eyes (7.5%). For four eyes (2.7%) a hyphema up to max 2 mm was documented, which also regressed until discharge. Two eyes (1.4%) reacted with temporary corneal opacity, one of them with stromal edema (0.7%). In also 5 eyes (3.5%) a choroidal amotio occurred, which also regressed in all cases after one day. Anterior chamber hemorrhage, iris contact, and an under-average anterior chamber were documented for 2 eyes each (1.4%). Three eyes (2%) showed single blood stains on the endothelium. In one eye each (0.7%), the following complications were recorded: Blood clot in the immediate vicinity of the stent, lower eyelid hematoma, the stent protruding too far into the anterior chamber (another surgical procedure was necessary for adequate placement in the chamber angle), conjunctival chemosis, endothelial obstruction. Postoperative complications At the final examination, only 3 of 40 eyes (7.5%) showed adherence of the iris to the XEN stent. In 2 of these eyes, the lumen was partially covered by iris tissue but still open. In the third eye, posterior synechiae had also been described preoperatively. These had no contact with the implant even at the final examination. No eye showed corneal opacities. The mean endothelial cell count was 1838.10 ± 546.28 cells/mm2 (M = 1932.0; range 666 to 2863; n = 40). All eyes were already pseudophakic. The mean cell number of the naive XEN group. Discussion In 2013, we performed the first XEN stent implantations as part of surgical glaucoma treatment at the Eye Clinic Neubrandenburg. These were patients in whom trabeculectomy was otherwise indicated. Since then, the procedure has become an established part of clinical routine in our hospital because of its high safety and good pressure-lowering effect. was 1951.15 ± 530.36 cells/mm2 (M = 1968.0; range, 736 to 2863; n = 20). In the group of patients with previous CyPass implantation, the cell number was lower, averaging 1725.05 ± 565.73 cells/mm2 (M = 1928.0; range, 662 to 2522; n = 20). However, the difference is not statistically significant (MWU test: p = 0.304; n = 20/20). In 3 eyes (7.5%) ptosis was documented postoperatively. In 5 eyes (12.5%) a posterior cataract developed over time. Three eyes (7.5%) showed mild blepharitis, two eyes (5%) showed sicca problems. Intraocular lens calcification, iridodonesis with lentodonesis, lower lid ectropion, pigmentary deposits on the lens, epiretinal gliosis, and vitreous opacities were documented for one eye each (2.5%). For 23 of 149 eyes (15%), the target pressure could not be achieved in the long term, requiring further surgical intervention. Because not much long-term data beyond 2 years is available to date [ 1 , 2 , 3 ], we designed the "investigator-initiated" study to collect our long-term data. To arrive at an average of 3 to 4 years of follow-up, we included only those patients who had undergone glaucoma surgery with XEN stenting by the end of 2018. The study population comprises 149 eyes. Of these, 23 (15%) had undergone repeat pressure-lowering surgery for glaucoma at the time of study enrollment. We defined these as treatment failures and did not invite them to participate in the study. We then had 126 eyes that were eligible and invited to participate in the study. Of these, 37 patients with 40 study eyes participated in the study. Of the remaining 86 eyes, 28 patients declined study participation, 24 had passed away, 5 had moved far away, 17 were too ill or unable to be transported, and we were unable to reach 12 patients. The data studied so far are from the 40 eyes with XEN stent implantation followed up, a total of 37 patients, with. Preoperatively, the mean number of drugs was 1.8 agents with a median of 2 agents and a range of 0 to 4 agents. At the 6-month follow-up, data were available from 17 eyes. Here, the number of pressure-lowering medications decreased to an average of 0.29 (median: 0) with a range of 0 to 4 agents. 15 eyes (88%) were drug-free at 6 months. At the 12-month follow-up, 17 eyes participated again. There was a mean medication count of 0.18 (median: 0 agents) and a range of 0 to 3 agents. Of these, 6 (95%) were drug-free. After 2 years, 18 eyes showed an average medication number of 0.61 agents (median: 0 agents) and a range of 0 to 4 agents. Here, 14 eyes were still drug-free. At the final examination after an average of 3.77 years, we determined an average number of 1.03 pressure-lowering agents in 40 follow-up eyes, a median value of 0 agents, and a range of 0 to 4 agents. There were still 23 eyes (58%) pressure-regulated without medication. (Fig. 1) The mean preoperative intraocular pressure (IOP) with therapy was 21.65 ± 8.81 mmHg with a median value of 20 mmHg and a range of 11 to 54 mmHg. IOP shows a significant decrease in the first 6 months to an average of 15.16 mmHg. The median value is 15 mmHg with a range of 8 to 25 mmHg. After 1 year, the average intraocular pressure is 15.06 ± 4.45 mmHg with the median value still being 15 mmHg with a range of 7 to 25 mmHg. After 2 years, we have an average intraocular pressure of 13.00 ± 2.40 mmHg and a median value of 13 mmHg with a range of 10 to 18 mmHg. After an average of 3 years, the final examination showed a mean intraocular pressure of 14.40 ± 4.96 mmHg and a median value of 13.5 mmHg and a range of 7 to 35 mmHg. (Fig. 2) 37 eyes (92%) achieved an intraocular pressure of ≤ 21 mmHg after 3 years with or without additional drug pressure reduction, of which 21 eyes were drug-free. An intraocular pressure of ≤ 18 mmHg is achieved by 34 eyes (85%), of which 19 eyes do not use medication. An intraocular pressure of ≤ 15 mmHg is achieved by 29 eyes (72%), of which 16 eyes are without pressure-lowering medication. (Fig. 3 ) The results of our survey underline the results of multicenter APEX study [ 5 ] and show the transferability of surgical results to individual others - in this case our clinic. In our survey there were no combined XEN implantations with cataract surgery (phacoemulsification). In 20 eyes (50%) of our survey, a suprachoroidal CyPass stent had already been inserted before XEN- implantation. The mean measured endothelial cell count in this group was 1725.05 ± 565.73 cells/m2 (range 662 to 2522; M = 1932) at the time of final follow-up. In the naïve XEN group (n = 20), the endothelial cell number at the final control averaged 1951.15 ± 530.36 cells/m2 (range, 736 to 2863; M = 1968). The difference is not statistically significant compared to the CyPass-XEN group (MWU test: p = 0.304; n = 20/20). Only in 3 XEN stent implantations did severe bleeding occur intraoperatively, but this was resolved at the end of surgery. No patient required postoperative anterior chamber irrigation. In each of the other operations, there was intraoperatively a severed vitreous cord, iris contact, complication due to unstable guidewire, pain, and a flat anterior chamber. In one eye, there was a perforated conjunctiva. Here, the tip of the implant had penetrated the conjunctiva. The implant protruded externally. Therefore, the conjunctiva was elevated in this area and injected with xylocitin so that the implant could completely retract subconjunctivally. The conjunctival perforation site was again injected with xylocitin so that it closed completely without the need for suturing. In the anterior chamber, there was only mild bleeding from the puncture site. Subconjunctivally, only a slight hemorrhage could also be completely removed from the anterior chamber when the healon was aspirated. (Fig. 4 ) Within 3.77 years, the XEN stent has a treatment failure rate of 15% in whom a repeat surgical glaucoma procedure was necessary. The most commonly used target pressure of maximum 18 mmHg is reached after 3 years in about three quarters of the reexamined eyes, with or without pressure-lowering medication. In our study, we explicitly included patients who had not yet received filtration procedures to ensure that an effect due to reactivation of the filtration function or a scarring tendency in the area of the filter pad could not occur. Nevertheless, there is evidence in the literature that XEN implantation may be beneficial after previous filtration surgery [ 6 ]. Considering the low intraoperative complication risks and the standardized handling of the procedure, the XEN stent achieves with these results a significant pressure-lowering effect over 3 years and confirms in our center its therapeutic potential in the context of microinvasive glaucoma surgery. In a national context, similar results as in our studies were registered and published by an Italian group [ 7 ]. For future developments of the XEN stent, further registration efforts should be made in a national or European context. Declarations Acknowledgements We thank AbbVie Deutschland GmbH & Co. KG for financial support for the study and the Dietrich Bonhoeffer Klinikum for the possibility to perform this Study. We thank the team of the Department of Ophthalmology, especially the participating investigators for examining the patients and the data science teamfor collecting data and providing and caring for study patients. Funding and Competing interests We mention there are no conflicts of interest associated with this publication, and there has been no signifact financial support for this work that could have influenced ist outcome This study was funded by AbbVie Deutschland GmbH & Co. KG No funding was received to assist with the preparation of this manuscript. The authors have no relevant financial or non-financial interests to disclose. All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest or non-financial interest in the subject matter or materials discussed in this manuscript. All procedures performed in studies involving human participants were in accordance with the ethical standards of the national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The study was approved (Date: 29th MAY2019; Reg. Nr: BB071/19) by the Ethics Committee of the Medical University of Greifswald [DE/EKMV22]. The study is registered in the German Register of Clinical Studies (DRKS00023619). Informed consent was obtained from all individual participants included in the study. Patients signed informed consent regarding publishing their data, too. Disclosures and declarations All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Ulrike Holland. The first draft of the manuscript was written by Christian Karl Brinkmann, Ulrike Holland and Ranny Abou Assaf and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. References Scheres LMJ, Kujovic-Aleksov S, Ramdas WD et al (2021) XEN® Gel Stent compared to PRESERFLO™ MicroShunt implantation for primary open-angle glaucoma: two-year results. Acta Ophthalmol. 99(3):e433-e440. 10.1111/aos.14602 . Epub 2020 Sep 10. PMID: 32909682 Gillmann K, Bravetti GE, Mermoud A et al (2019) XEN Gel Stent in Pseudoexfoliative Glaucoma: 2-Year Results of a Prospective Evaluation. J Glaucoma. 28(8):676–684. 10.1097/IJG.0000000000001295 . PMID: 31162174 Kalina AG, Kalina PH, Brown MM (2019) XEN® Gel Stent in Medically Refractory Open-Angle Glaucoma: Results and Observations After One Year of Use in the United States. Ophthalmol Ther. 8(3):435–446. 10.1007/s40123-019-0192-8 . Epub 2019 Jun 13. PMID: 31197608 Marcos-Parra MT, Mendoza-Moreira AL, Moreno-Castro L et al (2022) 3-Year Outcomes of XEN Implant Compared With Trabeculectomy, With or Without Phacoemulsification for Open Angle Glaucoma Journal of Glaucoma, Volume 31, Number 10, pp. 826–833(8) Reitsamer H, Vera V, Ruben S et al (2022) Three-year effectiveness and safety of the XEN gel stent as a solo procedure or in combination with phacoemulsification in open-angle glaucoma: a multicentre study. Acta Ophthalmol 100(1):e233–e245. 10.1111/aos.14886 Epub 2021 May 10 Bormann C, Schmidt M, Busch C et al (2022) Die XEN-Microstent-Implantation nach erfolgloser Trabekulektomie: eine sinnvolle Behandlungsoption? Klin Monbl Augenheilkd 239(01):86–93 Oddone F, Roberti G, Giammaria S et al (2023) Effectiveness and safety of XEN45 implant over 12 months of follow-up: data from the XEN-Glaucoma Treatment RegistryEye (Lond). 10.1038/s41433-023-02642-5 Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8618195","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":578698346,"identity":"a1828aed-78b0-4530-bb4b-64da618718e4","order_by":0,"name":"Christian Karl Brinkmann","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3klEQVRIiWNgGAWjYBACewbGBsYGEIv98AFphgMMCQwghA8YNsC08KQlEKfF4AADA0SLhI4BkbbMPtz2cGaOXZ65BM/H2wVn7uQxsCcfwO8XvsR2w43bkostZ/Butp5x41kxA88z/NYY9jC2ST7cxpy44QbvNmmeD4cTGyRyDPD75QxYSz1QC88zqJb8D4S1bNx2GKhFh02a5wbYFrw6IA6bue144oYzacbWM84cLmbjeYbfYfY87M8ke7dVJ244fvjh7YJjh/P42ZMf4LcGA7CRqH4UjIJRMApGARYAAPiiUfrehw2UAAAAAElFTkSuQmCC","orcid":"","institution":"Dietrich Bonhoeffer Klinikum","correspondingAuthor":true,"prefix":"","firstName":"Christian","middleName":"Karl","lastName":"Brinkmann","suffix":""},{"id":578698347,"identity":"378a0a34-faf1-4d82-bc6e-23882eb6106e","order_by":1,"name":"Ulrike Holland","email":"","orcid":"","institution":"Dietrich Bonhoeffer Klinikum","correspondingAuthor":false,"prefix":"","firstName":"Ulrike","middleName":"","lastName":"Holland","suffix":""},{"id":578698348,"identity":"1f4b05c7-ac11-4563-87c6-c32ffcae37f1","order_by":2,"name":"Ranny Abou Assaf","email":"","orcid":"","institution":"Dietrich Bonhoeffer Klinikum","correspondingAuthor":false,"prefix":"","firstName":"Ranny","middleName":"Abou","lastName":"Assaf","suffix":""}],"badges":[],"createdAt":"2026-01-16 11:28:26","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8618195/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8618195/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":103049527,"identity":"dd25b1d1-b957-410b-881c-937060249aff","added_by":"auto","created_at":"2026-02-20 07:42:11","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":36146,"visible":true,"origin":"","legend":"\u003cp\u003eBoxplot representation of the course of intraocular pressure postoperatively. The baseline median intraocular pressure is 20 mmHg with a postoperative decrease in the first year and relatively stable course over 3 years\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8618195/v1/e35ec147b73784d460699a61.png"},{"id":102963982,"identity":"3a8ed714-c1fb-4834-bec6-3aa94220ee0d","added_by":"auto","created_at":"2026-02-19 04:21:04","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":16217,"visible":true,"origin":"","legend":"\u003cp\u003ePercentage representation of the achieved pressure thresholds over the course of the 3 years independent of the supplementary medication\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8618195/v1/a4fff5ac459d9a6b13ed1cfa.png"},{"id":102964360,"identity":"ca9e4750-ecf3-4f84-a27f-02e30cf5320b","added_by":"auto","created_at":"2026-02-19 04:22:07","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":24809,"visible":true,"origin":"","legend":"\u003cp\u003eNumber of patients who reached a certain pressure value after 3 years\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-8618195/v1/5f8d82c9f93602ca3cbcbc90.png"},{"id":102939736,"identity":"bb538e93-da7d-4065-8560-efd4bc5ede68","added_by":"auto","created_at":"2026-02-18 16:57:33","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":21067,"visible":true,"origin":"","legend":"\u003cp\u003ePercentage plot of the applied agents in the course\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-8618195/v1/6767725649e92932a5bcae02.png"},{"id":102964472,"identity":"7fadca7f-4a4c-4a01-8b4e-aabae535f4ca","added_by":"auto","created_at":"2026-02-19 04:22:24","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":38337,"visible":true,"origin":"","legend":"\u003cp\u003eRepresentation of intraoperative complications\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-8618195/v1/f851ccfdb3e0c20fd4effb77.png"},{"id":104399570,"identity":"55a2b8b4-db80-4945-b11c-dcc7a84c0d9f","added_by":"auto","created_at":"2026-03-11 12:06:40","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":562455,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8618195/v1/382bb20c-58a0-4ce2-bd79-5bb6d3affea1.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"3-year results after XEN-45- stent implantation","fulltext":[{"header":"Background","content":"\u003cp\u003eSince December 2013, the XEN45 microstent has been used in surgical glaucoma treatment at the Department of Ophthalmology of the Dietrich-Bonhoeffer-Klinikum Neubrandenburg. So far, follow-up data after XEN microstent implantation up to 2 years have been published [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Long-term data beyond this are currently being increasingly published [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe purpose of this study is to collect long-term outcomes after XEN microstent implantation beyond 3 years. The long-term results are of considerable importance for the evaluation and positioning of the XEN stent procedure in surgical glaucoma therapy. The aim of this study is to collect data after an average of 3 years. It will be investigated to what extent the study results of multicenter studies can be transferred to a monoclinical setting.\u003c/p\u003e \u003cp\u003eThe question is to determine the effect of XEN microstent implantation on intraocular pressure (IOP) and the number of necessary antiglaucomatous therapies as well as the safety of the procedure based on the occurred intra- and postoperative complications.\u003c/p\u003e"},{"header":"Patients and Method","content":"\u003cp\u003eAll patients after implantation of a XEN microstent in at least one eye from December 2013 until the end of 2018 were scheduled for potential participation in the study. Patients of whom we already had the long-term data because they had been in the eye clinic for an examination in the meantime anyway were not revisited. The data were taken from the existing medical record and analyzed. The indication for surgery arose in all patients during the glaucoma consultation at the eye clinic. Patients with a history of suprachoroidal CyPass stent implantation and an indication for follow-up XEN stent implantation were included.\u003c/p\u003e \u003cp\u003eExcluded were eyes in which, apart from suprachoroidal CyPass stent implantation, a fistulous glaucoma surgery such as trabeculectomy or goniotrepanation was performed prior to XEN stent implantation.\u003c/p\u003e \u003cp\u003e 149 eyes were eligible for the study, of which 23 eyes had already undergone a second glaucoma pressure-lowering procedure at the time of the study. We defined these as treatment failures and did not invite them for follow-up.\u003c/p\u003e \u003cp\u003ePrimary endpoints were to determine the effect of XEN 45 microstent implantation on intraocular pressure, on the number of necessary antiglaucomatous agents applied, progression of glaucoma in terms of visual field deterioration and progression of glaucomatous optic disc changes, and loss of endothelial cells.\u003c/p\u003e \u003cp\u003eSecondary endpoints were the safety of the procedure based on the intraoperative and postoperative complications encountered, the development of the stent-associated subconjunctival oozing cushion, and the clinical identification of stent failures.\u003c/p\u003e \u003cp\u003eThe analyzed data presented below are from 40 of 126 eyes (excluding failures). 86 eyes (74 patients) could not participate in the study for various reasons.\u003c/p\u003e \u003cp\u003eThe statistical evaluation of the collected data was carried out with the program STATISTICA, version 13 (StatSoft, Hamburg, Germany) with T-Test, Wilcoxon and Mann Whitney U analysis.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eAt the time of the final examination, 23 eyes had already been defined as treatment failures (15%, n\u0026thinsp;=\u0026thinsp;149 eyes). The other patients were recalled to the clinic to participate in the study. 86 eyes did not participate in the study (58%, n\u0026thinsp;=\u0026thinsp;149 eyes). Of these, 28 (18%) patients/eyes had declined study participation, 24 (16%) patients had already died, 5 (4%) patients had moved too far, 17 patients were not transportable because of illness (11%), and 12 (8%) patients could not be reached. Of a total of 149 patient eyes invited for examination, 40 eyes of 37 patients [\u0026nbsp;Tab.] were followed up (27%, n\u0026thinsp;=\u0026thinsp;149 eyes).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDemographic data of 40 patients\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDemography n\u0026thinsp;=\u0026thinsp;40\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean (SD); Range\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge at surgery (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e71.58 (7.14); 54\u0026ndash;84\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge at follow-up (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e75.63 (7.09); 48\u0026ndash;90\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFollow-up duration (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.05 (1.33) 2.91\u0026ndash;3.98\u003c/p\u003e \u003cp\u003eMedian 3.77\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eGender\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eMale /Female\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18 (45%)/ 22 (55%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eEye\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eOD / OS\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22 (55%) / 18 (45%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e\n\u003ch3\u003eIntraocular pressure regulation\u003c/h3\u003e\n\u003cp\u003ePreoperative intraocular pressure averaged 21.65\u0026thinsp;\u0026plusmn;\u0026thinsp;8.93 mmHg (median\u0026thinsp;=\u0026thinsp;20.0 mmHg; range 11\u0026ndash;54 mmHg; n\u0026thinsp;=\u0026thinsp;40). During follow-up, intraocular pressure was 15.15\u0026thinsp;\u0026plusmn;\u0026thinsp;4.61 mmHg (median\u0026thinsp;=\u0026thinsp;15.0 mmHg; range 8\u0026ndash;25 mmHg; n\u0026thinsp;=\u0026thinsp;19; missing data: n\u0026thinsp;=\u0026thinsp;21), 15.06\u0026thinsp;\u0026plusmn;\u0026thinsp;4.45 mmHg (median\u0026thinsp;=\u0026thinsp;15.0 mmHg; range 7\u0026ndash;25 mmHg; n\u0026thinsp;=\u0026thinsp;17; missing data n\u0026thinsp;=\u0026thinsp;23), 12.05\u0026thinsp;\u0026plusmn;\u0026thinsp;2.76 mmHg (median\u0026thinsp;=\u0026thinsp;12.0 mmHg; range 8\u0026ndash;19 mmHg; n\u0026thinsp;=\u0026thinsp;20; missing data: n\u0026thinsp;=\u0026thinsp;20), and 13.00\u0026thinsp;\u0026plusmn;\u0026thinsp;2.40 mmHg (median\u0026thinsp;=\u0026thinsp;13.0 mmHg; range 10\u0026ndash;18 mmHg; n\u0026thinsp;=\u0026thinsp;18; missing data: n\u0026thinsp;=\u0026thinsp;22), respectively.\u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;1 Boxplot representation of the course of intraocular pressure postoperatively. The baseline median intraocular pressure is 20 mmHg with a postoperative decrease in the first year and relatively stable course over 3 years\u003c/p\u003e \u003cp\u003eAt the final examination, intraocular pressure averaged 14.40\u0026thinsp;\u0026plusmn;\u0026thinsp;4.96 mmHg (median\u0026thinsp;=\u0026thinsp;14.0 mmHg; range 7\u0026ndash;35\u003c/p\u003e \u003cp\u003e Fig 2. Percentage representation of the achieved pressure thresholds over the course of the 3 years independent of the supplementary medication\u003c/p\u003e \u003cp\u003emmHg; n\u0026thinsp;=\u0026thinsp;40). The mean pressure reduction compared with baseline pressure was 7.18\u0026thinsp;\u0026plusmn;\u0026thinsp;10.29 mmHg (range of pressure difference from baseline pressure\u0026thinsp;\u0026minus;\u0026thinsp;17 to +\u0026thinsp;40 mmHg, n\u0026thinsp;=\u0026thinsp;40 [Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e3\u003c/span\u003e]). The reduction in pressure at final examination, or the difference between baseline pressure and final findings is statistically significant (T-test; difference\u0026thinsp;=\u0026thinsp;7.18 mmHg; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; n\u0026thinsp;=\u0026thinsp;40) (Wilcoxon test; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; n\u0026thinsp;=\u0026thinsp;40).\u003c/p\u003e \u003cp\u003e37 eyes (92%) achieved an IOP of \u0026le;\u0026thinsp;21 mmHg after 3 years with or without additional drug pressure reduction, of which 21 eyes were drug-free. An intraocular pressure of \u0026le;\u0026thinsp;18 mmHg was achieved by 34 eyes (85%), of which 19 eyes were not using medication. An intraocular pressure of \u0026le;\u0026thinsp;15 mmHg was reached by 29 eyes (72%), of which 16 eyes were without pressure-lowering medication (Figs.\u0026nbsp;2 and \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe correlation between the number of preoperative pressure-lowering medication and the intraocular pressure at the final examination is statistically significant (Spearman; R=-0.321; p\u0026thinsp;=\u0026thinsp;0.044; n\u0026thinsp;=\u0026thinsp;40). The correlation between patient age at surgery and intraocular pressure at final examination is not statistically correlated (Spearman; R=-0.2297, p\u0026thinsp;=\u0026thinsp;0.154; n\u0026thinsp;=\u0026thinsp;40). The na\u0026iuml;ve eyes showed no significant difference in intraocular pressure at the final examination compared to the CyPass-preoperated eyes (na\u0026iuml;ve vs. preoperated: Mann-Whitney U (MWU) Test; Z=-1.021; p\u0026thinsp;=\u0026thinsp;0.307; n\u0026thinsp;=\u0026thinsp;40 [20 preoperated; 20 naive]).\u003c/p\u003e\n\u003ch3\u003eDrug Therapy\u003c/h3\u003e\n\u003cp\u003eThe mean number of pressure-lowering agents preoperatively was 1.83\u0026thinsp;\u0026plusmn;\u0026thinsp;1.22 agents (median\u0026thinsp;=\u0026thinsp;2.0; range 0\u0026ndash;4 agents, n\u0026thinsp;=\u0026thinsp;40). At 3, 6, 12, and 24 months, the mean was 0.26\u0026thinsp;\u0026plusmn;\u0026thinsp;0.78 (median\u0026thinsp;=\u0026thinsp;0.0; range 0\u0026ndash;3, n\u0026thinsp;=\u0026thinsp;19; missing data: n\u0026thinsp;=\u0026thinsp;21), 0.29\u0026thinsp;\u0026plusmn;\u0026thinsp;0.96 (median\u0026thinsp;=\u0026thinsp;0.0; range 0\u0026ndash;4, n\u0026thinsp;=\u0026thinsp;17; missing data: n\u0026thinsp;=\u0026thinsp;23), 0.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.85 (median\u0026thinsp;=\u0026thinsp;0.0; range 0\u0026ndash;3, n\u0026thinsp;=\u0026thinsp;20; missing data: n\u0026thinsp;=\u0026thinsp;20), and 0.61\u0026thinsp;\u0026plusmn;\u0026thinsp;1.21 (median\u0026thinsp;=\u0026thinsp;0.0; range 0\u0026ndash;4, n\u0026thinsp;=\u0026thinsp;18; missing data: n\u0026thinsp;=\u0026thinsp;22). At the final examination, the mean number of pressure-lowering medications was 1.03\u0026thinsp;\u0026plusmn;\u0026thinsp;1.33 (median\u0026thinsp;=\u0026thinsp;0.0; range 0\u0026ndash;4, n\u0026thinsp;=\u0026thinsp;40 [Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e4\u003c/span\u003e]).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eHere, the difference from baseline findings is highly statistically significant. (T-test; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; n\u0026thinsp;=\u0026thinsp;40) (Wilcoxon test; p\u0026thinsp;=\u0026thinsp;0.002; n\u0026thinsp;=\u0026thinsp;40).\u003c/p\u003e\n\u003ch3\u003eCourse of visual acuity\u003c/h3\u003e\n\u003cp\u003eVisual acuity was documented and evaluated as a decimal number. Mean baseline visual acuity was 0.72\u0026thinsp;\u0026plusmn;\u0026thinsp;0.27 (median\u0026thinsp;=\u0026thinsp;0.8; range 0.10\u0026ndash;1.00; n\u0026thinsp;=\u0026thinsp;40). At 3, 6, 12, and 24 months, the mean was 0.76\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22 (median\u0026thinsp;=\u0026thinsp;0.8; range 0.20\u0026ndash;1.00; n\u0026thinsp;=\u0026thinsp;19; missing data: n\u0026thinsp;=\u0026thinsp;21), 0.79\u0026thinsp;\u0026plusmn;\u0026thinsp;0.19 (median\u0026thinsp;=\u0026thinsp;0.7; range 0.40\u0026ndash;1.00; n\u0026thinsp;=\u0026thinsp;17; missing data: n\u0026thinsp;=\u0026thinsp;23), 0.79\u0026thinsp;\u0026plusmn;\u0026thinsp;0.25 (median\u0026thinsp;=\u0026thinsp;0.79; range 0.10\u0026ndash;1.00; n\u0026thinsp;=\u0026thinsp;20; missing data: n\u0026thinsp;=\u0026thinsp;20), and 0.68\u0026thinsp;\u0026plusmn;\u0026thinsp;0.25 (median\u0026thinsp;=\u0026thinsp;0.8; range 0.10\u0026ndash;1.00; n\u0026thinsp;=\u0026thinsp;18; missing data: n\u0026thinsp;=\u0026thinsp;22). At the final examination, the mean value was 0.68 (M\u0026thinsp;=\u0026thinsp;0.67) with a range of 0.10\u0026ndash;1.25; n\u0026thinsp;=\u0026thinsp;40. Visual acuity at the final examination was not significantly different from preoperative visual acuity (Wilcoxon test; p\u0026thinsp;=\u0026thinsp;0.322; n\u0026thinsp;=\u0026thinsp;40) (T-test; p\u0026thinsp;=\u0026thinsp;0.328; n\u0026thinsp;=\u0026thinsp;40).\u003c/p\u003e\n\u003ch3\u003eVisual field\u003c/h3\u003e\n\u003cp\u003ePreoperatively, mean deviation averaged\u0026thinsp;\u0026minus;\u0026thinsp;11.19\u0026thinsp;\u0026plusmn;\u0026thinsp;7.70 dB (median=-10.30; range\u0026thinsp;\u0026minus;\u0026thinsp;30.27 to +\u0026thinsp;2.61 dB; n\u0026thinsp;=\u0026thinsp;40). At 3, 6, 12, and 24 months, the MD averaged\u0026thinsp;\u0026minus;\u0026thinsp;12.69\u0026thinsp;\u0026plusmn;\u0026thinsp;5.54 dB (median=-11.53; range\u0026thinsp;\u0026minus;\u0026thinsp;20.26 to -2.45 dB; n\u0026thinsp;=\u0026thinsp;10; missing data: n\u0026thinsp;=\u0026thinsp;30), -8.05\u0026thinsp;\u0026plusmn;\u0026thinsp;6.84 dB (median=-6.14; range\u0026thinsp;\u0026minus;\u0026thinsp;20.17 to +\u0026thinsp;0.67 dB; n\u0026thinsp;=\u0026thinsp;14; missing data:\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003en\u0026thinsp;=\u0026thinsp;26), -10.40\u0026thinsp;\u0026plusmn;\u0026thinsp;8.02 dB (median=-8.17; range\u0026thinsp;\u0026minus;\u0026thinsp;26.69 to +\u0026thinsp;0.31 dB; n\u0026thinsp;=\u0026thinsp;12; missing data: n\u0026thinsp;=\u0026thinsp;28), and \u0026minus;\u0026thinsp;12.55\u0026thinsp;\u0026plusmn;\u0026thinsp;8.28 dB (median=-12.06; range\u0026thinsp;\u0026minus;\u0026thinsp;30.24 to +\u0026thinsp;0.44 dB; n\u0026thinsp;=\u0026thinsp;13; missing data: n\u0026thinsp;=\u0026thinsp;27).\u003c/p\u003e \u003cp\u003eAt the final examination, MD averaged\u0026thinsp;\u0026minus;\u0026thinsp;13.27\u0026thinsp;\u0026plusmn;\u0026thinsp;9.04 dB (median=-11.96; range\u0026thinsp;\u0026minus;\u0026thinsp;30.24 to +\u0026thinsp;1.31 dB; n\u0026thinsp;=\u0026thinsp;36; missing data: n\u0026thinsp;=\u0026thinsp;4). Visual field testing with the Humphrey device was not possible in four patients.\u003c/p\u003e \u003cp\u003eThe difference between the preoperative MD and the MD at the final examination was on average\u0026thinsp;\u0026minus;\u0026thinsp;1.85\u0026thinsp;\u0026plusmn;\u0026thinsp;6.44 dB. This difference is statistically significant (T-test; p\u0026thinsp;=\u0026thinsp;0.0318; n\u0026thinsp;=\u0026thinsp;35) (Wilcoxon test; p\u0026thinsp;=\u0026thinsp;0.004; n\u0026thinsp;=\u0026thinsp;35). Thirteen of 35 follow-up eyes (37%) showed MD reduction of more than 3 dB after an average of 3.77 years. A progression of more than 5 dB could be detected in only 7 eyes (20%) (n\u0026thinsp;=\u0026thinsp;35, missing data: n\u0026thinsp;=\u0026thinsp;5). On average, there was a change in MD of -1.68\u0026thinsp;\u0026plusmn;\u0026thinsp;4.38 dB/year in the eyes examined postoperatively (range\u0026thinsp;\u0026minus;\u0026thinsp;12.95 to +\u0026thinsp;12.55 dB; n\u0026thinsp;=\u0026thinsp;35).\u003c/p\u003e \u003cp\u003eThe number of visual field points in the central 5-degree visual field with a sensitivity\u0026thinsp;\u0026le;\u0026thinsp;10 dB averaged 0.56\u0026thinsp;\u0026plusmn;\u0026thinsp;1.01 points preoperatively (range, 0\u0026ndash;4 points; n\u0026thinsp;=\u0026thinsp;40). At 3, 6, 12, and 24 months, this number averaged 0.50\u0026thinsp;\u0026plusmn;\u0026thinsp;0.92 points (range 0\u0026ndash;3 points; n\u0026thinsp;=\u0026thinsp;10; missing data: n\u0026thinsp;=\u0026thinsp;30), 0.29\u0026thinsp;\u0026plusmn;\u0026thinsp;0.59 points (range 0\u0026ndash;2 points; n\u0026thinsp;=\u0026thinsp;14; missing data: n\u0026thinsp;=\u0026thinsp;26), 0.83\u0026thinsp;\u0026plusmn;\u0026thinsp;1.28 points (range 0\u0026ndash;4 points; n\u0026thinsp;=\u0026thinsp;12; missing data: n\u0026thinsp;=\u0026thinsp;28), and 0.62\u0026thinsp;\u0026plusmn;\u0026thinsp;1.15 points (range 0\u0026ndash;4 points; n\u0026thinsp;=\u0026thinsp;13; missing data: n\u0026thinsp;=\u0026thinsp;27), respectively. At the final examination, this number averaged 0.89\u0026thinsp;\u0026plusmn;\u0026thinsp;1.25 points (range, 0\u0026ndash;4 points; n\u0026thinsp;=\u0026thinsp;35; missing data: n\u0026thinsp;=\u0026thinsp;5). At five patients, visual field testing with the Humphrey device was not possible due to limited visual acuity or poor cooperation.\u003c/p\u003e \u003cp\u003eThe reduction in the number of central visual field defects was not statistically significant compared to baseline findings in the T-test (T-test; p\u0026thinsp;=\u0026thinsp;0.216; n\u0026thinsp;=\u0026thinsp;35). In contrast, the Wilcoxon test showed significance (Wilcoxon test; p\u0026thinsp;=\u0026thinsp;0.012; n\u0026thinsp;=\u0026thinsp;35).\u003c/p\u003e \u003cp\u003eThe pattern standard deviation (PSD) averaged 6.14\u0026thinsp;\u0026plusmn;\u0026thinsp;3.41 dB preoperatively (M\u0026thinsp;=\u0026thinsp;5.88; range 1.47\u0026ndash;14.30 dB; n\u0026thinsp;=\u0026thinsp;40). At 3, 6, 12, and 24 months, this value was 7.58\u0026thinsp;\u0026plusmn;\u0026thinsp;2.60 dB (M\u0026thinsp;=\u0026thinsp;8.04; range, 2.38\u0026ndash;10.59 dB; n\u0026thinsp;=\u0026thinsp;10; missing data: n\u0026thinsp;=\u0026thinsp;30), 5.95\u0026thinsp;\u0026plusmn;\u0026thinsp;3.73 dB (M\u0026thinsp;=\u0026thinsp;4.21; range, 1.33\u0026ndash;1.89 dB; n\u0026thinsp;=\u0026thinsp;14; missing data: n\u0026thinsp;=\u0026thinsp;26), 6.35\u0026thinsp;\u0026plusmn;\u0026thinsp;2.91 dB (M\u0026thinsp;=\u0026thinsp;6.41; range, 1.49\u0026ndash;1.75 dB; n\u0026thinsp;=\u0026thinsp;12; missing data: n\u0026thinsp;=\u0026thinsp;28), and 6.19\u0026thinsp;\u0026plusmn;\u0026thinsp;3.46 dB (M\u0026thinsp;=\u0026thinsp;6.49; range, 1.44\u0026ndash;13.00 dB; n\u0026thinsp;=\u0026thinsp;38; missing data: n\u0026thinsp;=\u0026thinsp;37) and 5.79\u0026thinsp;\u0026plusmn;\u0026thinsp;4.03 dB (range, 1.39\u0026ndash;15.90 dB; n\u0026thinsp;=\u0026thinsp;14; missing data: n\u0026thinsp;=\u0026thinsp;26). At the final examination, the PSD value averaged 6.86\u0026thinsp;\u0026plusmn;\u0026thinsp;3.69 dB (M\u0026thinsp;=\u0026thinsp;6.91; range, 1.40\u0026ndash;14.26 dB; n\u0026thinsp;=\u0026thinsp;35; missing data: n\u0026thinsp;=\u0026thinsp;5).\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eOptic disc morphology HRT II\u003c/h2\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003e(Heidelberg Retinal Tomography)\u003c/h2\u003e \u003cp\u003eThe average rim area preoperatively was 1.12\u0026thinsp;\u0026plusmn;\u0026thinsp;0.43 mm\u0026sup2; (range 0.35\u0026ndash;1.98 mm\u0026sup2;; M\u0026thinsp;=\u0026thinsp;1.10 mm\u0026sup2;; n\u0026thinsp;=\u0026thinsp;39; missing data: n\u0026thinsp;=\u0026thinsp;1). After 3, 6, 12, and 24 months, the rim area averaged 1.12\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10 mm\u0026sup2; (range 0.99\u0026ndash;1.23 mm\u0026sup2;; M\u0026thinsp;=\u0026thinsp;1.13 mm\u0026sup2;; n\u0026thinsp;=\u0026thinsp;4; missing data; n\u0026thinsp;=\u0026thinsp;36), 1.07\u0026thinsp;\u0026plusmn;\u0026thinsp;0.40 mm\u0026sup2; (range 0.39, \u0026minus;\u0026thinsp;1.92 mm\u0026sup2;; M\u0026thinsp;=\u0026thinsp;1.14 mm\u0026sup2;; n\u0026thinsp;=\u0026thinsp;12; missing data: n\u0026thinsp;=\u0026thinsp;28), 1.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.33 mm\u0026sup2; (span 0.45\u0026ndash;1.56 mm\u0026sup2;; M\u0026thinsp;=\u0026thinsp;1.02 mm\u0026sup2;; n\u0026thinsp;=\u0026thinsp;13; missing data: n\u0026thinsp;=\u0026thinsp;7), and 1.20\u0026thinsp;\u0026plusmn;\u0026thinsp;0.65 mm\u0026sup2; (span 0.12\u0026ndash;2.47 mm\u0026sup2;; M\u0026thinsp;=\u0026thinsp;1.10 mm\u0026sup2;; n\u0026thinsp;=\u0026thinsp;13; missing data: n\u0026thinsp;=\u0026thinsp;27). At the final examination, the rim area averaged 1.15\u0026thinsp;\u0026plusmn;\u0026thinsp;0.55 mm\u0026sup2; (range 0.05\u0026ndash;2.47 mm\u0026sup2;; M\u0026thinsp;=\u0026thinsp;1.05mm\u0026sup2;; n\u0026thinsp;=\u0026thinsp;37; missing data: n\u0026thinsp;=\u0026thinsp;3 eyes). In three patients no HRT measurement was possible due to lack of cooperation of patients.\u003c/p\u003e \u003cp\u003eThe difference between the preoperative findings and the findings at the final examination was not statistically significant (T-test: p\u0026thinsp;=\u0026thinsp;0.774; Wilcoxon test; p\u0026thinsp;=\u0026thinsp;0.968; n\u0026thinsp;=\u0026thinsp;37).\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e\n\u003ch3\u003eOptic disc morphology by nerve fiber OCT\u003c/h3\u003e\n\u003cp\u003eNerve fiber evaluation is performed by the number of damaged segments and the extent of damage of each segment. There are 12 segments to be evaluated in each measurement. The healthy segments (shown in green) are classified as 0 points, the moderately damaged segments (shown in yellow) are classified as 1 point, and the markedly damaged segments in red are classified as 2 points. The total number of points is summed The mean score of optic disc morphology by RNFL-OCT was 8.70\u0026thinsp;\u0026plusmn;\u0026thinsp;6.16 preoperatively (range, 0\u0026ndash;22; M\u0026thinsp;=\u0026thinsp;8.50; n\u0026thinsp;=\u0026thinsp;30; missing data: n\u0026thinsp;=\u0026thinsp;10). At the final examination, this value was 8.56\u0026thinsp;\u0026plusmn;\u0026thinsp;4.49 (range 0\u0026ndash;16; M\u0026thinsp;=\u0026thinsp;10.00; n\u0026thinsp;=\u0026thinsp;27; missing data: n\u0026thinsp;=\u0026thinsp;13). This difference tends to show an improvement and excludes a worsening of findings on nerve fiber OCT. The difference between baseline and final findings is not statistically significant (T-test; p\u0026thinsp;=\u0026thinsp;0.263; n\u0026thinsp;=\u0026thinsp;27) (Wilcoxon test; p\u0026thinsp;=\u0026thinsp;0.177; n\u0026thinsp;=\u0026thinsp;27).\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eFiltering blebs morphology\u003c/h2\u003e \u003cp\u003eThree months postoperatively, all eyes showed a slightly prominent filtering bleb (100%; n\u0026thinsp;=\u0026thinsp;10; missing data\u0026thinsp;=\u0026thinsp;30). At 6, 12, and 24 months, a filtering bleb was presentable in 13 (93%; n\u0026thinsp;=\u0026thinsp;14; missing data\u0026thinsp;=\u0026thinsp;26), 17 (100%, n\u0026thinsp;=\u0026thinsp;17, missing data\u0026thinsp;=\u0026thinsp;23), and 12 (86%; n\u0026thinsp;=\u0026thinsp;14; missing data\u0026thinsp;=\u0026thinsp;26), respectively. At the final examination, 36 of 40 eyes examined had a filtering bleb (90%; n\u0026thinsp;=\u0026thinsp;40;), and the filtering bleb was still prominent in 7 of these 36 eyes.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eIntraoperative complications\u003c/h2\u003e \u003cp\u003eIn 119 (80%) of 149 eyes, no intraoperative complications were documented based on the surgical reports. In 19 eyes (13%) minor bleeding (reflux hemorrhage) occurred. In three surgical reports (2%) severe intraoperative bleeding was described, which required further measures. In each case, the anterior chamber was filled with viscoelastic until hemostasis occurred. The blood was aspirated together with the viscoelastic at the end of the operation without any problems.\u003c/p\u003e \u003cp\u003eIn two operations, increased resistance occurred during implantation of the stent, which could be overcome with a second approach. In one surgery, intraoperative iris contact, complication of unstable guidewire, pain, and shallow anterior chamber occurred. In one eye, conjunctival perforation occurred through the tip of the implant. The conjunctival perforation site was re-injected with xylocitin so that it closed completely, the implant remained subconjunctival without the need for suturing. An only mild anterior chamber hemorrhage during aspiration of the healon could be completely removed from the anterior chamber (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e[32 of 149 eyes were operated combined with phacoemulsification and posterior chamber lens implantation. 2 eyes showed hemorrhages in the anterior chamber, in one eye the stent had to be repositioned. Within the first week, cells were documented for 4 eyes and blood cells for 7 eyes. Four eyes developed fibrin in the anterior chamber]\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eEarly postoperative complications\u003c/h2\u003e \u003cp\u003eWhile the patient was still in hospital, the anterior segment of the eye was examined clinically every day for 3 to 4 days and any abnormalities were documented. 78 (52%) of 149 eyes showed no complications within the first 4 days. 12 (8%) of 149 eyes showed anterior chamber cells in the early postoperative course, 41 eyes (27.5%) showed blood cells, and 8 eyes (5.5%) showed fibrin reactions (of these, five eyes had been operated on combined with phacoemulsification and posterior chamber lens implantation; the fibrin reaction here cannot be clearly attributed to the stent implantation). Transient hyposphagma was seen in 11 eyes (7.5%). For four eyes (2.7%) a hyphema up to max 2 mm was documented, which also regressed until discharge. Two eyes (1.4%) reacted with temporary corneal opacity, one of them with stromal edema (0.7%). In also 5 eyes (3.5%) a choroidal amotio occurred, which also regressed in all cases after one day. Anterior chamber hemorrhage, iris contact, and an under-average anterior chamber were documented for 2 eyes each (1.4%). Three eyes (2%) showed single blood stains on the endothelium.\u003c/p\u003e \u003cp\u003eIn one eye each (0.7%), the following complications were recorded: Blood clot in the immediate vicinity of the stent, lower eyelid hematoma, the stent protruding too far into the anterior chamber (another surgical procedure was necessary for adequate placement in the chamber angle), conjunctival chemosis, endothelial obstruction.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003ePostoperative complications\u003c/h2\u003e \u003cp\u003eAt the final examination, only 3 of 40 eyes (7.5%) showed adherence of the iris to the XEN stent. In 2 of these eyes, the lumen was partially covered by iris tissue but still open. In the third eye, posterior synechiae had also been described preoperatively. These had no contact with the implant even at the final examination. No eye showed corneal opacities. The mean endothelial cell count was 1838.10\u0026thinsp;\u0026plusmn;\u0026thinsp;546.28 cells/mm2 (M\u0026thinsp;=\u0026thinsp;1932.0; range 666 to 2863; n\u0026thinsp;=\u0026thinsp;40). All eyes were already pseudophakic. The mean cell number of the naive XEN group.\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn 2013, we performed the first XEN stent implantations as part of surgical glaucoma treatment at the Eye Clinic Neubrandenburg. These were patients in whom trabeculectomy was otherwise indicated. Since then, the procedure has become an established part of clinical routine in our hospital because of its high safety and good pressure-lowering effect. was 1951.15\u0026thinsp;\u0026plusmn;\u0026thinsp;530.36 cells/mm2 (M\u0026thinsp;=\u0026thinsp;1968.0; range, 736 to 2863; n\u0026thinsp;=\u0026thinsp;20). In the group of patients with previous CyPass implantation, the cell number was lower, averaging 1725.05\u0026thinsp;\u0026plusmn;\u0026thinsp;565.73 cells/mm2 (M\u0026thinsp;=\u0026thinsp;1928.0; range, 662 to 2522; n\u0026thinsp;=\u0026thinsp;20). However, the difference is not statistically significant (MWU test: p\u0026thinsp;=\u0026thinsp;0.304; n\u0026thinsp;=\u0026thinsp;20/20).\u003c/p\u003e \u003cp\u003eIn 3 eyes (7.5%) ptosis was documented postoperatively. In 5 eyes (12.5%) a posterior cataract developed over time. Three eyes (7.5%) showed mild blepharitis, two eyes (5%) showed sicca problems. Intraocular lens calcification, iridodonesis with lentodonesis, lower lid ectropion, pigmentary deposits on the lens, epiretinal gliosis, and vitreous opacities were documented for one eye each (2.5%).\u003c/p\u003e \u003cp\u003eFor 23 of 149 eyes (15%), the target pressure could not be achieved in the long term, requiring further surgical intervention.\u003c/p\u003e \u003cp\u003eBecause not much long-term data beyond 2 years is available to date [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], we designed the \"investigator-initiated\" study to collect our long-term data. To arrive at an average of 3 to 4 years of follow-up, we included only those patients who had undergone glaucoma surgery with XEN stenting by the end of 2018.\u003c/p\u003e \u003cp\u003eThe study population comprises 149 eyes. Of these, 23 (15%) had undergone repeat pressure-lowering surgery for glaucoma at the time of study enrollment. We defined these as treatment failures and did not invite them to participate in the study. We then had 126 eyes that were eligible and invited to participate in the study. Of these, 37 patients with 40 study eyes participated in the study.\u003c/p\u003e \u003cp\u003eOf the remaining 86 eyes, 28 patients declined study participation, 24 had passed away, 5 had moved far away, 17 were too ill or unable to be transported, and we were unable to reach 12 patients.\u003c/p\u003e \u003cp\u003e The data studied so far are from the 40 eyes with XEN stent implantation followed up, a total of 37 patients, with.\u003c/p\u003e \u003cp\u003ePreoperatively, the mean number of drugs was 1.8 agents with a median of 2 agents and a range of 0 to 4 agents. At the 6-month follow-up, data were available from 17 eyes. Here, the number of pressure-lowering medications decreased to an average of 0.29 (median: 0) with a range of 0 to 4 agents. 15 eyes (88%) were drug-free at 6 months. At the 12-month follow-up, 17 eyes participated again. There was a mean medication count of 0.18 (median: 0 agents) and a range of 0 to 3 agents. Of these, 6 (95%) were drug-free.\u003c/p\u003e \u003cp\u003eAfter 2 years, 18 eyes showed an average medication number of 0.61 agents (median: 0 agents) and a range of 0 to 4 agents. Here, 14 eyes were still drug-free.\u003c/p\u003e \u003cp\u003eAt the final examination after an average of 3.77 years, we determined an average number of 1.03 pressure-lowering agents in 40 follow-up eyes, a median value of 0 agents, and a range of 0 to 4 agents. There were still 23 eyes (58%) pressure-regulated without medication. (Fig.\u0026nbsp;1)\u003c/p\u003e \u003cp\u003eThe mean preoperative intraocular pressure (IOP) with therapy was 21.65\u0026thinsp;\u0026plusmn;\u0026thinsp;8.81 mmHg with a median value of 20 mmHg and a range of 11 to 54 mmHg. IOP shows a significant decrease in the first 6 months to an average of 15.16 mmHg. The median value is 15 mmHg with a range of 8 to 25 mmHg.\u003c/p\u003e \u003cp\u003eAfter 1 year, the average intraocular pressure is 15.06\u0026thinsp;\u0026plusmn;\u0026thinsp;4.45 mmHg with the median value still being 15 mmHg with a range of 7 to 25 mmHg. After 2 years, we have an average intraocular pressure of 13.00\u0026thinsp;\u0026plusmn;\u0026thinsp;2.40 mmHg and a median value of 13 mmHg with a range of 10 to 18 mmHg.\u003c/p\u003e \u003cp\u003eAfter an average of 3 years, the final examination showed a mean intraocular pressure of 14.40\u0026thinsp;\u0026plusmn;\u0026thinsp;4.96 mmHg and a median value of 13.5 mmHg and a range of 7 to 35 mmHg. (Fig.\u0026nbsp;2)\u003c/p\u003e \u003cp\u003e37 eyes (92%) achieved an intraocular pressure of \u0026le;\u0026thinsp;21 mmHg after 3 years with or without additional drug pressure reduction, of which 21 eyes were drug-free. An intraocular pressure of \u0026le;\u0026thinsp;18 mmHg is achieved by 34 eyes (85%), of which 19 eyes do not use medication. An intraocular pressure of \u0026le;\u0026thinsp;15 mmHg is achieved by 29 eyes (72%), of which 16 eyes are without pressure-lowering medication. (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e3\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eThe results of our survey underline the results of multicenter APEX study [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] and show the transferability of surgical results to individual others - in this case our clinic. In our survey there were no combined XEN implantations with cataract surgery (phacoemulsification).\u003c/p\u003e \u003cp\u003eIn 20 eyes (50%) of our survey, a suprachoroidal CyPass stent had already been inserted before XEN- implantation. The mean measured endothelial cell count in this group was 1725.05\u0026thinsp;\u0026plusmn;\u0026thinsp;565.73 cells/m2 (range 662 to 2522; M\u0026thinsp;=\u0026thinsp;1932) at the time of final follow-up. In the na\u0026iuml;ve XEN group (n\u0026thinsp;=\u0026thinsp;20), the endothelial cell number at the final control averaged 1951.15\u0026thinsp;\u0026plusmn;\u0026thinsp;530.36 cells/m2 (range, 736 to 2863; M\u0026thinsp;=\u0026thinsp;1968). The difference is not statistically significant compared to the CyPass-XEN group (MWU test: p\u0026thinsp;=\u0026thinsp;0.304; n\u0026thinsp;=\u0026thinsp;20/20).\u003c/p\u003e \u003cp\u003eOnly in 3 XEN stent implantations did severe bleeding occur intraoperatively, but this was resolved at the end of surgery. No patient required postoperative anterior chamber irrigation. In each of the other operations, there was intraoperatively a severed vitreous cord, iris contact, complication due to unstable guidewire, pain, and a flat anterior chamber. In one eye, there was a perforated conjunctiva. Here, the tip of the implant had penetrated the conjunctiva. The implant protruded externally. Therefore, the conjunctiva was elevated in this area and injected with xylocitin so that the implant could completely retract subconjunctivally. The conjunctival perforation site was again injected with xylocitin so that it closed completely without the need for suturing. In the anterior chamber, there was only mild bleeding from the puncture site. Subconjunctivally, only a slight hemorrhage could also be completely removed from the anterior chamber when the healon was aspirated. (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e4\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eWithin 3.77 years, the XEN stent has a treatment failure rate of 15% in whom a repeat surgical glaucoma procedure was necessary. The most commonly used target pressure of maximum 18 mmHg is reached after 3 years in about three quarters of the reexamined eyes, with or without pressure-lowering medication.\u003c/p\u003e \u003cp\u003eIn our study, we explicitly included patients who had not yet received filtration procedures to ensure that an effect due to reactivation of the filtration function or a scarring tendency in the area of the filter pad could not occur. Nevertheless, there is evidence in the literature that XEN implantation may be beneficial after previous filtration surgery [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eConsidering the low intraoperative complication risks and the standardized handling of the procedure, the XEN stent achieves with these results a significant pressure-lowering effect over 3 years and confirms in our center its therapeutic potential in the context of microinvasive glaucoma surgery.\u003c/p\u003e \u003cp\u003eIn a national context, similar results as in our studies were registered and published by an Italian group [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. For future developments of the XEN stent, further registration efforts should be made in a national or European context.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cem\u003eAcknowledgements\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eWe thank AbbVie Deutschland GmbH \u0026amp; Co. KG \u0026nbsp;for financial support for the study and the Dietrich Bonhoeffer Klinikum for the possibility to perform this Study. We thank the team of the Department of Ophthalmology, especially the participating investigators for examining the patients and the data science teamfor collecting data and providing and caring for study patients.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eFunding and Competing interests\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eWe mention there are no conflicts of interest associated with this publication, and there has been no signifact financial support for this work that could have influenced ist outcome\u003c/p\u003e\n\u003cp\u003eThis study was funded by AbbVie Deutschland GmbH \u0026amp; Co. KG \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNo funding was received to assist with the preparation of this manuscript. The authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003cp\u003eAll authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest or non-financial interest in the subject matter or materials discussed in this manuscript.\u003c/p\u003e\n\u003cp\u003eAll procedures performed in studies involving human participants were in accordance with the ethical standards of the national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The study was approved (Date: 29th MAY2019; Reg. Nr: BB071/19) by the Ethics Committee of the Medical University of Greifswald [DE/EKMV22]. The study is registered in the German Register of Clinical Studies (DRKS00023619).\u003c/p\u003e\n\u003cp\u003eInformed consent was obtained from all individual participants included in the study. Patients signed informed consent regarding publishing their data, too.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eDisclosures and declarations\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Ulrike Holland. The first draft of the manuscript was written by Christian Karl Brinkmann, Ulrike Holland and Ranny Abou Assaf and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eScheres LMJ, Kujovic-Aleksov S, Ramdas WD et al (2021) XEN\u0026reg; Gel Stent compared to PRESERFLO\u0026trade; MicroShunt implantation for primary open-angle glaucoma: two-year results. Acta Ophthalmol. 99(3):e433-e440. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/aos.14602\u003c/span\u003e\u003cspan address=\"10.1111/aos.14602\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2020 Sep 10. PMID: 32909682\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGillmann K, Bravetti GE, Mermoud A et al (2019) XEN Gel Stent in Pseudoexfoliative Glaucoma: 2-Year Results of a Prospective Evaluation. J Glaucoma. 28(8):676\u0026ndash;684. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/IJG.0000000000001295\u003c/span\u003e\u003cspan address=\"10.1097/IJG.0000000000001295\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 31162174\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKalina AG, Kalina PH, Brown MM (2019) XEN\u0026reg; Gel Stent in Medically Refractory Open-Angle Glaucoma: Results and Observations After One Year of Use in the United States. Ophthalmol Ther. 8(3):435\u0026ndash;446. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s40123-019-0192-8\u003c/span\u003e\u003cspan address=\"10.1007/s40123-019-0192-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2019 Jun 13. PMID: 31197608\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMarcos-Parra MT, Mendoza-Moreira AL, Moreno-Castro L et al (2022) 3-Year Outcomes of XEN Implant Compared With Trabeculectomy, With or Without Phacoemulsification for Open Angle Glaucoma Journal of Glaucoma, Volume 31, Number 10, pp. 826\u0026ndash;833(8)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eReitsamer H, Vera V, Ruben S et al (2022) Three-year effectiveness and safety of the XEN gel stent as a solo procedure or in combination with phacoemulsification in open-angle glaucoma: a multicentre study. Acta Ophthalmol 100(1):e233\u0026ndash;e245. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/aos.14886\u003c/span\u003e\u003cspan address=\"10.1111/aos.14886\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003eEpub 2021 May 10\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBormann C, Schmidt M, Busch C et al (2022) Die XEN-Microstent-Implantation nach erfolgloser Trabekulektomie: eine sinnvolle Behandlungsoption? Klin Monbl Augenheilkd 239(01):86\u0026ndash;93\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOddone F, Roberti G, Giammaria S et al (2023) Effectiveness and safety of XEN45 implant over 12 months of follow-up: data from the XEN-Glaucoma Treatment RegistryEye (Lond). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1038/s41433-023-02642-5\u003c/span\u003e\u003cspan address=\"10.1038/s41433-023-02642-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"glaucoma surgery, microstent, Intraocular pressure, drop therapy","lastPublishedDoi":"10.21203/rs.3.rs-8618195/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8618195/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCurrently, few studies are available on long-term outcomes after XEN microstent implantation beyond three years. This article is to collect 3-year outcomes regarding the efficacy and safety of the XEN-45 stent.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData were collected from 149 eyes undergoing XEN(Abbvie, Germany) implantation at our hospital from December 2013 to November 2018.\u003c/p\u003e\n\u003cp\u003eAs criteria for efficacy, we use intraocular pressure (IOP), number of pressure-lowering medications, and need for reoperation. As criteria for safety, we list intraoperative complications.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe mean patient age at surgery was 72.44 ± 7.99 years (range 54 to 85 years, n=149). 56% of the patients were female. 15% of these 149 eyes (n=23) required further glaucoma surgery. Forty eyes of 37 patients came to the clinic for follow-up at recall. The median follow-up time was 45.92 months (3.77 years).\u003c/p\u003e\n\u003cp\u003eApproximately 92% (n=37) of eyes without \u0026nbsp;follow-up surgery (n=40) achieved an IOP of ≤ 21 mmHg with or without additional medications, approximately 85% (n=34) achieved an IOP of ≤ 18 mmHg, and approximately 72% (n=29) achieved an IOP of ≤ 15 mmHg.\u003c/p\u003e\n\u003cp\u003eIntraoperative complications occurred in 20% of eyes (n=149). The majority of these were minor intracameral hemorrhages at 13%. More severe bleeding occurred in only 3 (2%) eyes No postoperative hemorrhage requiring anterior chamber irrigation occurred in any eye.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe XEN microstent achieves a sufficient pressure-lowering effect over 3 years and is characterized by high intraoperative safety. The study is registered in the German Register of Clinical Studies (DRKS00023619; 19th November 2020).\u003c/p\u003e","manuscriptTitle":"3-year results after XEN-45- stent implantation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-18 16:57:28","doi":"10.21203/rs.3.rs-8618195/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"cba6514b-1f02-445d-b73a-538469d15820","owner":[],"postedDate":"February 18th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-02-28T07:25:13+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-18 16:57:28","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8618195","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8618195","identity":"rs-8618195","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}