Fornix-based versus limbus-based conjunctival flap in trabeculectomy: a quantitative evaluation of the evidence

Comparison of Aurolab Aqueous Drainage Implant with Ahmed Glaucoma Valve for Refractory Glaucoma: A Meta-Analysis

BACKGROUND

Ahmed glaucoma valve (AGV) is a common surgical method for the treatment of refractory glaucoma.Aurolab aqueous drainage implant (AADI) is a novel surgical method which has been applied in clinical practice in recent years.

OBJECTIVE

The purpose of this study was to compare the efficacy and safety of the AADI and the AGV for the treatment of refractory glaucoma.

METHODS

We comprehensively searched four databases, including PubMed, Embase, Web of Science, and the Cochrane Library databases, selecting the relevant studies. The continuous variables, namely, intraocular pressure reduction (IOPR) and a reduction in antiglaucoma medication (AGMR), were pooled by the weighted mean differences (WMDs), and the dichotomous outcomes, including success rates and complications, were pooled by the odds ratio (OR).

RESULTS

A total of 825 eyes from 820 patients from six studies were included. The WMDs of the IOPR between the AADI and the AGV implant were 0.58 (95% CI: 0.07-1.09) at 3 months, 0.44 (95% CI: 0.11-0.77) at 6 months, 2.20 (95% CI: 0.63-3.77) at 12 months, and 3.24 (95% CI: 1.73-4.75) at follow-up endpoint. Significant difference was detected between the two groups at any point in time. The WMDs of the AGMR between the AADI and the AGV implant were 0.87 (95% CI: 0.61-1.13) at 6 months, 1.04 (95% CI: 0.66-1.42) at 12 months, and 0.93 (95% CI: 0.52-1.34) at the follow-up endpoint; the differences reached statistical significance at any point in time. The pooled ORs comparing the AADI with the AGV were 3.64 (95% CI: 2.44-5.45) for the complete success rate and 1.72 (95% CI: 1.24-2.39) for qualified success rate; significant difference was detected between the two groups. There were no significant differences between the AADI and the AGV implant on the rates of adverse events.

CONCLUSIONS

The AADI is more effective in both its surgical success rate and reducing IOP and AGM. And the two implants may have comparable incidences of adverse events.

The Tenons' Layer Reposition Approach of Trabeculectomy: A Longitudinal Case Series of a Mixed Group of Glaucoma Patients

SYNOPSIS

This 1-year prospective study demonstrated that the Tenon's layer reposition approach of trabeculectomy could achieve zero leakage rate, minimal rate of transient hypotony without compromising the surgical outcome.

PURPOSE

The purpose of this study was to investigate the effectiveness and safety of a Tenon's layer reposition approach of trabeculectomy.

METHODS

A prospective, noncomparative case series of 30 eyes of 30 Chinese patients with mixed types of glaucoma who underwent fornix-based trabeculectomy combined with intraoperative mitomycin C application. During the conjunctival flap closure, the Tenons' layer was identified, separated, and anchored on to the sclera surface with 8/0 vicryl, followed by conjunctival closure with 10/0 nylon as a separate layer. All patients were followed up for 1 year. Assessment including intraocular pressure (IOP), vertical cup-disc ratio measurement, best-corrected visual acuity, and visual field examination were performed before and after the operation. Qualified and complete success was defined as IOP of ≤21 mm Hg in 2 consecutive visits with or without medication, respectively. Outcomes were evaluated using scattered plot and Kaplan-Meier survival curve.

RESULTS

Twenty-one eyes (70%) and 28 eyes (93.3%) achieved complete and partial success at 1 year, respectively. There was a significant reduction of IOP (28.5±9.6 to 15.5±2.6 mm Hg, P<0.001) and medication use (4.4±0.9 to 0.8±1.2 bottles/eye, P<0.001). There were no significant changes in best-corrected visual acuity, vertical cup-disc ratio, and visual field indices. No wound leak was identified throughout the study. The procedure did not induce significant astigmatic change. Other postoperative complications, including 2 eyes (6.7%) with transient hypotony and 1 eye (3.3%) required cataract surgery, were of relatively low rate.

CONCLUSION

The Tenon's layer reposition approach of performing trabeculectomy is a safe and efficacious procedure for Chinese subjects with different types of glaucoma.

Suture Removal After Trabeculectomy With Fornix-based Conjunctival Flap Leads to Faster Visual Recovery but Not Reduced Astigmatism

PRéCIS:: The closing limbal suture after trabeculectomy with a fornix-based conjunctival flap plays no critical role in the development of corneal astigmatism and intraocular pressure (IOP). A standard removal is not recommended.

PURPOSE

To investigate the effect of removal of the conjunctival suture after trabeculectomy with fornix-based conjunctival flap on corneal astigmatism, visual acuity, and IOP.

METHODS

Eighty-seven cases of trabeculectomy with mitomycin C with a fornix-based conjunctival flap performed in the eyes of 82 patients (5 patients underwent bilateral trabeculectomy) were enrolled in a prospective randomized study. All surgeries were conducted by the same surgeon (J.W.) in the Ophthalmology Department of the University Medical Center of Mainz, Germany. All eyes received a corneal-conjunctival, continuous, mattress, interlocked suture for closing the conjunctiva at the limbus. After randomization, in 46 cases the suture was removed 6 weeks postoperatively; in 41 patients, the suture was left in place. All patients were examined preoperatively, and at 6 weeks, 3 months, 6 months, and 12 months after surgery. Astigmatism was measured using objective refraction and corneal topography, IOP and visual acuity were also assessed. Results were compared using a Wilcoxon test or Mann-Whitney U test for single time-points.

RESULTS

During follow-up, no significant differences between the 2 study groups regarding refractive or topographic values were found. Patients in the suture removal group had a significantly higher visual acuity than controls at 3 months, 6 months, and 1 year after surgery. IOP was similar in both groups throughout the study.

CONCLUSIONS

Removal of the conjunctival suture in trabeculectomy with a fornix-based conjunctival flap leads to a faster rehabilitation of visual acuity but does not significantly affect corneal astigmatism or IOP.

The impact of conjunctival flap method and drainage cannula diameter on bleb survival in the rabbit model

PURPOSE

To examine the effect of cannula diameter and conjunctival flap method on bleb survival in rabbits undergoing cannula-based glaucoma filtration surgery (GFS).

METHODS

Twelve New Zealand White rabbits underwent GFS in both eyes. The twenty-four eyes were divided into four groups. Two of the four groups (N = 12) received limbus-based conjunctival flaps (LBCF), and the other two (N = 12) received fornix-based conjunctival flaps (FBCF). Six FBCF rabbit eyes were implanted with 22-gauge drainage tubes, and the other six were implanted with 26-gauge tubes. Likewise, six LBCF rabbits received 22-gauge drainage tubes and six received 26-gauge tubes. Filtration blebs were evaluated every three days by a masked observer. Bleb failure was defined as the primary endpoint in this study and was recorded after two consecutive flat bleb evaluations.

RESULTS

Group 1 (LBCF, 22- gauge cannula) had a mean bleb survival time (Mean ± SD) of 18.7 ± 2.9 days. Group 2 (LBCF, 26-gauge cannula) also had a mean bleb survival time of 18.7 ± 2.9 days. Group 3 (FBCF, 22-gauge cannula) had a mean bleb survival time of 19.2 ± 3.8 days. Group 4 (FBCF, 26-gauge cannula) had a mean bleb survival time of 19.7 ± 4.1 days. A 2-way analysis of variance showed that neither surgical approach nor cannula gauge made a statistically significant difference in bleb survival time (P = 0.634 and P = 0.874). Additionally, there was no significant interaction between cannula gauge and conjunctival flap approach (P = 0.874), suggesting that there was not a combination of drainage gauge and conjunctival flap method that produced superior bleb survival.

CONCLUSION

Limbus and fornix-based conjunctival flaps are equally effective in promoting bleb survival using both 22 and 26-gauge cannulas in the rabbit model. The 26-gauge drainage tube may be preferred because its smaller size facilitates the implantation process, reducing the risk of corneal contact.

Clinical Outcomes of Ahmed Glaucoma Valve Implantation With or Without Intravitreal Bevacizumab Pretreatment for Neovascular Glaucoma: A Systematic Review and Meta-Analysis

PURPOSE

To evaluate the efficacy and tolerability of Ahmed glaucoma valve (AGV) implantation with intravitreal bevacizumab injection (IVB) pretreatment in the treatment of neovascular glaucoma (NVG).

METHODS

A comprehensive literature search was performed according to the Cochrane collaboration methodology to identify controlled clinical trials comparing AGV implantation with (IVB group) or without IVB (control group) pretreatment for NVG. The main outcome measures were the weighted mean differences (WMDs) for intraocular pressure reduction, a reduction in glaucoma medications, odds ratio (OR) for complete success rates, and qualified success rates. Tolerability estimates were measured by OR for adverse events.

RESULTS

The WMD of the intraocular pressure reduction when comparing the IVB group with the control group was 3.30 (-1.21 to 7.80). The IVB group was associated with numerically greater but nonsignificant IOP lowering efficacy compared with the control group (P=0.152). Both groups were comparable in the reduction of glaucoma medication, with a WMD of 0.28 (-0.03 to 0.59) at the follow-up endpoint (P=0.077). The IVB group was associated with significant greater complete success rates compared with the control group, with a pooled OR of 3.18 (1.41 to 7.19). However, it did not show a significant difference for the qualified success rate between them, with a pooled OR of 2.00 (0.95 to 4.21). The IVB group was associated with a significantly lower frequency of hyphema than the control group, with a pooled OR of 0.15 (0.07 to 0.32).

CONCLUSION

The use of IVB pretreatment for NVG is a safe and effective additional step during AGV implantation surgery.

The relationship of bleb morphology and the outcome of needle revision with 5-fluorouracil in failing filtering bleb

To investigate the risk factors for failure of needling revision with 5-fluorouracil (5-FU) and to identify the correlation of outcomes of needling revision and the morphological features of dysfunctional filtration blebs using Moorfields bleb grading system.This retrospective, nonrandomized, comparative case-control study included 41 consecutive patients (41 eyes) who underwent 5-FU needling revision for failed or failing filtration blebs between July 2012 and August 2014 in Chang Gung Memorial Hospital, a referral center in Taiwan. The main outcome measures were the bleb survival and the correlation factors of bleb morphology before revision. The secondary outcome measure was the identification of any study factor associated with bleb failure.Forty-one eyes of 41 patients were included in this study. The most frequent glaucoma diagnoses were 10 cases (24%) of neovascular glaucoma and 8 cases (19%) of chronic open-angle glaucoma. Survival of bleb at 6, 12, and 24 months was 42%, 39%, and 23%. Fourteen cases (34%) maintained overall success at the last follow-up, with an average follow-up of 22.7 ± 9.4 months (range: 12-48 months). The central bleb area and height were significantly different between the successful needling group and the failed needling group (P = 0.03 and 0.04, respectively). Further trend test confirmed that smaller central bleb extension and flatter height were associated with a higher chance of failure (P = 0.02 and 0.02, respectively). Time from initial trabeculectomy to needling of less than 4 months and higher intraocular pressure (IOP) in the first postoperative week also led to significantly higher risk for failure (P = 0.01 and 0.03, respectively).A small central area and the flat height of dysfunctional blebs were more likely to fail after the needle revision. Cautious case selections, taking account of the time from the initial filtering surgery and postoperative IOP, may improve the surgical outcome.

The Ahmed shunt versus the Baerveldt shunt for refractory glaucoma: a meta-analysis

Background

The purpose of this study was to compare the efficacy and tolerability of the Ahmed glaucoma valve (AGV) implant and the Baerveldt implant for the treatment of refractory glaucoma.

Methods

We comprehensively searched four databases, including PubMed, EMBASE, Web of Science, and the Cochrane Library databases, selecting the relevant studies. The continuous variables, namely, intraocular pressure reduction (IOPR) and a reduction in glaucoma medication, were pooled by the weighted mean differences (WMDs), and the dichotomous outcomes, including success rates and tolerability estimates, were pooled by the odds ratio (ORs).

Results

A total of 929 patients from six studies were included. The WMDs of the IOPR between the AGV implant and the Baerveldt implant were 1.58 [95 % confidence interval (CI): −2.99 to 6.15] at 6 months, −1.01 (95 % CI: −3.40 to 1.98) at 12 months, −0.54 (95 % CI: −4.89 to 3.82) at 24 months, and −0.47 (95 % CI: −3.29 to 2.35) at 36 months. No significant difference was detected between the two groups at any point in time. The pooled ORs comparing the AGV implant with the Baerveldt implant were 0.51 (95 % CI: 0.33 to 0.80) for the complete success rate and 0.67 (95 % CI: 0.50 to 0.91) for qualified success rate. The Baerveldt implant was associated with a reduction in glaucoma medication at −0.51 (95 % CI: −0.90 to −0.12). There were no significant differences between the AGV implant and the Baerveldt implant on the rates of adverse events.

Conclusions

The Baerveldt implant is more effective in both its surgical success rate and reducing glaucoma medication, but it is comparable to the AGV implant in lowering IOP. Both implants may have comparable incidences of adverse events.

Limbus- versus fornix-based trabeculectomy for open-angle glaucoma eyes with prior ocular surgery: the Collaborative Bleb-Related Infection Incidence and Treatment Study

We compared the surgical successes of limbus- and fornix-based trabeculectomies in open-angle glaucoma (OAG) eyes that had prior ocular surgery in the Collaborative Bleb-Related Infection Incidence and Treatment Study (CBIITS), Japan. From the 1,098 glaucoma eyes in 34 clinical centers in CBIITS, 195 OAG eyes that had undergone previous trabeculectomy and/or lens extraction were included. Limbus- or fornix-based trabeculectomy with mitomycin C were performed. Surgical failure (IOP ≥ 21, 18, or 15 mmHg for criterion A, B or C, respectively; <20% decrease from baseline; reoperation for glaucoma; or loss of light perception vision) was counted. There were 106 and 89 eyes treated with limbus- and fornix-based trabeculectomies, respectively. At 3 years, IOP (mean ± SD) was 12.5 ± 5.9 and 14.1 ± 6.4 mmHg and the cumulative probabilities of failure during 3 years were 30.2% and 50.5% for criterion A, 40.3% and 57.4% for criterion B, and 57.9% and 65.8% for criterion C in the limbus- and the fornix-based group, respectively. Fornix-based incisions were associated with surgical failure in Cox-proportional multivariable analysis for criterion A [relative risk (RR) = 1.96], and B [RR = 1.60]. Limbus-based trabeculectomy had a higher probability of success in OAG eyes with prior ocular surgery.