Clinical outcome of a nonvalved Aurolab aqueous drainage implant in posterior segment versus anterior chamber

Aurolab Aqueous Drainage Implant (AADI): Review of Indications, Mechanism, Surgical Technique, Outcomes, Impact and Limitations

PURPOSE

The purpose of this review is to place together all the knowledge available on aurolab aqueous drainage implant (AADI) in one place for the benefit of all glaucoma specialists who are interested in low-cost implants in developing world with desired results.

METHODS

A comprehensive literature search was done on AADI and its use in glaucoma management. 35 results were obtained from the literature search. Out of these 35, 2 were commentaries, 6 were case reports and rest 27 were studies (prospective and retrospective) discussing the surgical outcomes, modifications and comparison of AADI with other glaucoma drainage devices (GDDs). Out of these, 2 commentaries were excluded and rest 33 articles were included, cited and discussed appropriately in this review.

RESULTS

AADI resulted in a significant reduction in the intra ocular pressure (IOP) and also in the number of antiglaucoma medications. AADI can be implanted alone or combined with cataract surgery. It was found to be beneficial in both pediatric and adult refractory glaucoma. There was no significant difference seen in the pre and post operative visual acuity. But AADI was also associated with various hypotony related and tube related early and late onset complications. Some of these complications were managed conservatively and some needed surgical intervention.

CONCLUSIONS

AADI is a low-cost non-valved GDD with successful results in both adult as well as pediatric refractory glaucomas. Early and late onset complications are common and can be managed with appropriate and timely medical or surgical intervention.

Retinal detachment in eyes treated with Aurolab aqueous drainage implant for refractory glaucoma - Incidence and outcomes

Purpose:

To analyze the incidence of rhegmatogenous retinal detachment (RRD) in patients who have undergone prior Aurolab aqueous drainage implant (AADI) surgery and report outcomes in terms of anatomic, visual acuity, and intraocular pressure (IOP) findings.

Methods:

Case records of all patients who underwent RRD repair after AADI surgery from 2013 to 2019 were retrospectively analyzed. Data collected included patient demographics, ocular examination findings at all visits including IOP and best-corrected visual acuity (BCVA) and clinical findings related to RRD both at baseline and postoperatively.

Results:

Ten eyes of nine patients were included in study. The mean age of patients was 28.2 years (median: 15 years, range: 6–83 years). Mean duration between AADI and RRD was 14 months (median 2.5 months; range 2 days-72 months). All eyes underwent pars plana vitrectomy with silicon oil injection. The preoperative LogMAR BCVA (logarithm of the minimum angle of resolution) was 2.52 ± 0.15 which improved to 2.29 ± 0.58 at final follow-up; however, only one eye had vision ≥ 20/400 largely due to recurrent RRD and advanced glaucomatous disc damage. Postoperatively retina was attached in 6 eyes (60%) and IOP was ≤ 21 mmHg in 5 out of 6 eyes with anatomic success

Conclusion:

The incidence of RRD following AADI was found to be 0.86% in our study. Pars plana vitrectomy (PPV) with silicon oil tamponade was the preferred approach in the management of these eyes with IOP being well controlled post PPV. However, visual acuity outcomes were largely unsatisfactory due to recurrent RRD and preexisting advanced glaucoma.

Pars plana Aurolab aqueous drainage implantation for refractory glaucoma: Outcome of a new modified technique

PURPOSE

To report the outcomes of pars plana insertion of Aurolab aqueous drainage implant (AADI) in adults with refractory glaucoma by the novel technique of making scleral tunnel instead of patch graft to cover the tube to prevent its migration.

METHODS

A retrospective study was done between April 2016 and April 2018 on patients with ≥12 months of follow-up. The main outcome measure was a surgical failure at 12 months. The failure was defined as intraocular pressure (IOP) >18 mmHg or IOP ≤5 mmHg on two consecutive follow-up visits after 3 months, reoperation for glaucoma, loss of light perception vision, or implant explantation. Alternate definitions of failure including IOP >21 and IOP >15 mmHg were also considered.

RESULTS

: The study included 32 eyes of 32 patients. The mean age was 46.2 ± 17.5 years. The most common etiology is traumatic glaucoma (12 eyes, 37.5%). The mean preoperative IOP and anti-glaucoma medications were 43.3 ± 10.3 and 3.4 ± 0.5 mmHg, respectively; both the parameters at the final follow-up were reduced to 15.2 ± 8.1 and 1.6 ± 0.5 mmHg. The Kaplan-Meier survival estimates demonstrated that the cumulative probability of failure was 15.6% (95% CI; 6.8-33.5%) at 3 months, 18.7% (95% CI; 8.9-37.0%) at 6 months, and 25.0% (95% CI; 13.4-43.8%) at 12 months.

CONCLUSION

Pars plana AADI implantation with a newer modification technique is a useful procedure in reducing IOP and the number of anti-glaucoma medications in the eyes with refractory glaucoma. The visual acuity may be stabilized with the concurrent treatment of posterior segment pathology.

Surgical outcomes of the Aurolab aqueous drainage implant (AADI) versus the Ahmed glaucoma valve for refractory paediatric glaucoma in Middle Eastern children

Objective

The Aurolab aqueous drainage implant (AADI) has the potential advantages of less encapsulation and greater cost-effectiveness than the Ahmed glaucoma valve (AGV). The aim of this study was to compare the surgical success and outcomes of the AADI compared to the AGV in Middle-Eastern children.

Methods

A comparative retrospective study of consecutive paediatric patients in a tertiary eye hospital was undertaken. Data collected included demographics, type of glaucoma, intraocular pressure (IOP), number of anti-glaucoma medications (AGMs) and any subsequent complications or further surgeries.

Analysis

The mean IOP, number of AGMs, surgical success and number of reoperations was compared for the two groups. Surgical success at each visit was defined as IOP of ≥6 mm Hg and ≤21 mm Hg or if the reduction of IOP was ≥20% reduced from baseline.

Results

A total of 126 tube surgeries (56 eyes in AADI and 70 eyes in AGV) were performed in patients aged ≤18 years from 2014 to 2019. No difference was observed in the mean IOP between the two groups except at the first month post-operative visit. After six months, the AADI group had a consistently significant lower mean number of AGMs. At last follow-up, 21 (37.5%) eyes in the AADI group were glaucoma medication-free vs 15 (21.4%) eyes in the AGV group (pp=0.047). Kaplan-Meier analysis showed equivalent cumulative probability of success at two years of 69.9% [(45.9%–84.9%)] for AADI vs 66.8% [(53.4%–77.1%])) for the AGV, respectively. Twenty-four eyes in the AGV group needed one or more subsequent surgeries, whereas 13 eyes needed one or more surgery in the AADI group.

Conclusions

This study shows an acceptable safety profile for the AADI in children, with a rate of failure that is comparable to the AGV, but less need for glaucoma re-operation or glaucoma medication in the first post-postoperative year.

Aurolab aqueous drainage implant in the vitreous cavity: Our modifications over the conventional technique of glaucoma implant surgery

Glaucoma drainage devices (GDDs) are used for managing refractory glaucoma due to failed trabeculectomy, neovascular glaucoma, traumatic glaucoma, and secondary glaucoma post keratoplasty. Aurolab aqueous drainage implant (AADI) is a nonvalved drainage implant conventionally implanted with the tube placed in the anterior chamber. Studies about the outcome of the various aqueous drainage devices implanted in the anterior chamber have reported complications such as tube extrusion, migration, blockage, erosion, and corneal decompensation. We propose modifying the conventional GDD implantation technique by placing the tube in the vitreous cavity, thereby negating the risk of anterior segment complications in patients with refractory glaucoma whose anterior segment is already compromised. Another novel approach implemented in this technique was making a scleral tunnel instead of using a scleral or corneal patch graft to cover the tube to prevent its migration. This article describes the surgical steps of this technique and its advantages, along with a surgical video.

Outcome of a low-cost glaucoma drainage device with posterior chamber/pars plana insertion of the tube

INTRODUCTION

The Aurolab aqueous drainage implant (AADI) is a low-cost glaucoma drainage device that is modelled on the Baerveldt glaucoma implant. Studies on AADI have reported absolute success rates of 41.8-93.1% at 1 year. Most studies report on tube placement in the anterior chamber. We report on results of tube insertion in the sulcus/pars plana.

MATERIAL AND METHODS

A retrospective chart review of all patients who had undergone AADI implantation (with insertion of tube in the sulcus/posterior segment) between June 2015 and November 2018 was done. Patients were asked to stop anti-glaucoma medications on the 40th post-operative day.

RESULTS

The mean age was 57.4 ± 13.8 years (n = 30). The mean IOP prior to surgery was 34.4 ± 6.1 mmHg which reduced to 15.4 ± 8.6 mmHg on the 45th post-operative day (p < 0.001). The absolute success at last review was 10% and the qualified success was 80%. The complication rate was 26.7%. Three patients had hypotony related complications noted at/after the 45th day review (none before 40th day). The incidence of ocular motility disturbances was 26.7% though none of the patients reported diplopia. One patient had sideways rotation of the scleral patch graft resulting in tube exposure. This complication was not seen after we shifted to using 9-0 nylon sutures to anchor the graft. Six patients had loss of best corrected visual acuity and one patient developed endophthalmitis. The endophthalmitis was preceded by conjunctival retraction and sloughing off of the scleral patch graft.

DISCUSSION

AADI implantation results in a substantial drop in IOP. However, many patients continue to require anti-glaucoma medications. Allowing overlap of scleral/corneal patch graft onto the scleral flap may be effective in preventing peritubular leak. It may be advisable to use 9-0 nylon sutures to secure the scleral patch graft anti-glaucoma medications can be temporarily suspended after the 40th post-operative day to minimize hypotony related complications. Melting of the scleral patch graft may be an early sign of endophthalmitis. It would be prudent to specifically look for ocular motility problems in patients undergoing AADI implantation.