Limbal reconstruction in uveitic glaucoma patient with exposed Ahmed valve coincident with corneal melting and iris prolapse using multiple corneoscleral allografts

Aim: To present a complex case of Ahmed tube exposure 6 months after the implantation associated with corneal melting and iris prolapse, and the surgical reposition that required multiple allografts and limbal reconstruction. Methods: A 60-year-old patient arrived at the emergency room with tube exposure combined with corneal melting and iris prolapse from a previously placed Ahmed valve 6 months prior. Our approach was to use one corneoscleral graft to repair the melted cornea and avoid further iris prolapse and a second scleral graft to cover the repositioned tube. Upon completion of conjunctival dissection, cleaning and deepithelization of the melted cornea and the tube by application of alcohol 100% followed. A new entry point was made for the tube and was covered using an alcohol-preserved scleral allograft and the previous entry point was repaired using a corneoscleral allograft with the corneal aspect restoring the limbus and avoiding further iris protrusion. Results: 6 months follow-up of the patient showed excellent recovery, anatomical restoration, and IOP normalization. Conclusion: Surgical repair of these cases can be very demanding, and requires surgical improvisation and prolonged surgical time. The literature remains very limited on how a surgeon should approach similar cases, which are the crucial tips, and which are the missteps that should be avoided. In this case, we used multiple scleral/corneoscleral allografts in a specific orientation and different sutures to reconstruct the damaged limbal area and restore the anatomy. Abbreviations: VA = Visual Acuity, GDD = Glaucoma Drainage Device, IOP = Intra Ocular Pressure.

Double scleral tunnel technique to prevent glaucoma drainage device exposure

PURPOSE

To describe a new surgical technique designed to reduce the risk of tube exposure following glaucoma drainage device (GDD) surgery.

METHODS

A retrospective, single-center study included all patients who underwent GDD surgery by a single surgeon between January 2018 and December 2019, using a double scleral tunnel technique to secure the tube to the sclera. A 23-gauge needle was used to create a 3 mm partial thickness scleral tunnel near to the GDD plate, with a second partial thickness scleral tunnel created 2.5 mm from the surgical limbus into the anterior chamber (AC). The silicone tube was passed through both scleral tunnels and into the AC.

RESULTS

46 GDD surgeries were performed during the time frame. The mean age of patients was 65 ± 13 years. Mean follow up duration was 27.7 ± 8.15 months (range 11 to 44). Significant reductions in intraocular pressure and number of glaucoma medications were achieved. Zero exposures were recorded occurring during follow-up.

CONCLUSION

This double scleral tunnel technique to secure the GDD silicone tubing firmly to the sclera may reduce micro-movements which have been purported to be associated with tissue erosion post GDD surgery. The addition of this simple technique to existing GDD surgery may reduce the risk of post-operative tube exposure.

Management of Ahmed glaucoma valve tube exposure after scleral patch graft shrinkage

Background

Ahmed glaucoma valve (AGV) is an useful modality in the management of medically refractory glaucoma. Human donor scleral patch graft (SPG) can be employed to cover the external portion of the tube to prevent its exposure and associated sight-threatening complication.

Purpose

To report the management of a case of AGV tube exposure due to SPG shrinkage in the right eye (RE) of a patient.

Synopsis

Under peribulbar anesthesia, the conjunctiva is undermined posteriorly, on either side of the exposed tube. The AGV tube is noted to lay firmly against the sclera without any excessive movement. The shrunk and displaced SPG is excised, and a larger, 6 × 8 mm, full-thickness, human donor SPG is placed on the episcleral bed, over the exposed segment of the tube, to ensure its adequate coverage. The SPG is sutured with four interrupted, 10-0 nylon sutures. The SPG is adequately covered with conjunctiva, by conjunctival mobilization and advancement to avoid excessive tension over the tube and closed with interrupted, 8-0 Vicryl suture.

Highlights

SPG shrinkage and overlying conjunctival erosion can occur after AGV implantation. This can cause AGV tube exposure, which can be managed by donor SPG to cover the exposed tube.

Online Video Link

https://youtu.be/36Y0n22SxPU.

The best thickness of cornea graft from SMILE surgery as patch graft in glaucoma drainage implant surgery

OBJECTIVE

The aim of this study was to determine the best thickness of corneal slices acquired from femtosecond laser surgery-small incision lenticule extraction (SMILE surgery) as patch graft in glaucoma drainage implantation surgery.

METHODS

This study is a prospective randomized study. Patients who received glaucoma drainage implantation from September 2016 to November 2018 were observed. The patients were randomly divided into 3 groups. Group A included 102 cases (104 eyes), receiving 1 layer (120-150 μm) of allogeneic lamellar corneal tissue as the graft. Group B included 117 cases (120 eyes), receiving 2 layers of lamellar corneal tissue from one donor. Group C included 109 cases (111 eyes), using 3 layers of lamellar corneal tissue from 2 donors. The intraocular pressure, corneal graft, conjunctiva stromalysis, drainage tube exposure, and drainage plate were observed.

RESULTS

Patients were followed up for 6 to 33 months. The intraocular pressure was significantly reduced after surgery in all three groups. Conjunctiva stromalysis and drainage tubes were exposed in 3 eyes (3%) in group A and 1 eye (0.8%, a special case which has nystagmus and the plate was placed infratemporally) in group B, whereas no conjunctiva stromalysis or tube exposure was reported in group C.

CONCLUSIONS

The corneal graft acquired from SMILE surgery can effectively prevent drainage tube exposure and give patients a better cosmetic appearance. Two layers of lamellar corneal tissue (240-300 μm) may be the best suitable thickness because it can effectively reduce tube exposure and rejection. In some special cases, 3 layers of lamellar corneal tissue are needed.

Tube Revision Outcomes for Exposure with Different Repair Techniques

Purpose

The aim of this study was to report our experience with eyes that presented with an initial GDD exposure and their subsequent outcome in terms of re-exposure.

Methods

A retrospective review of charts of 42 patients (43 eyes) who presented with a GDD exposure during the period 2008–2015 in a tertiary eye care center was performed. Demographic data, past ocular history, pre-operative and post-operative information including the surgical technique of GDD surgery and exposure repair were recorded. The patients were followed for further exposure to the date of the last follow-up clinic visit. For each type of repair technique, details were collected on risk and timing of GDD exposure. The baseline features of eyes that had further exposure after initial exposure were compared to eyes without further exposure.

Results

Forty-three eyes were identified which had repair after an initial exposure. The mean ± SD age was 54 ± 27 years. Of the GDDs, Ahmed FP7 was performed in 31 eyes, Ahmed FP8 in two eyes, Ahmed S2 in five eyes, Krupin valve in two eyes and Baerveldt 350 GDD in three eyes. The methods of repair and the relative risk [95% CI] of re-exposure were: conjunctival closure only (n=4; RR=2.10 [0.84–5.23]); repair with patch graft and conjunctival repair (n=18), RR=1.24 [0.51–3.01]; tube repositioning, use of patch graft and conjunctival repair (n=14), RR=1.0; tube removal with replacement in a different quadrant, patch graft and conjunctival repair (n=3), RR=1.87 [0.64–5.48]. After the first exposure, 18 eyes had a second re-exposure, four eyes had a third re-exposure, and 1 eye had a fourth exposure.

Conclusions

The GDD exposure rates at our institution are consistent with other reports. Lack of a patch graft for repair is associated with a two-fold risk of subsequent re-exposure.

Infectious and Sterile Endophthalmitis in Eyes with Glaucoma Drainage Device from Two Large Ophthalmic Institutions

PURPOSE

To describe the predisposing factors, presentation, management, and outcome of glaucoma drainage implant (GDI)-associated endophthalmitis.

DESIGN

Retrospective chart review.

PARTICIPANTS

Eyes that developed GDI-associated endophthalmitis between December 1, 2011, and December 23, 2019, at the Duke Eye Center and Cole Eye Institute.

METHODS

Patient data search was performed on the basis of diagnostic codes for GDI and endophthalmitis. Endophthalmitis was defined clinically according to each physician's discretion. Eyes with infection source other than GDI were excluded. Worse vision was defined as a decrease of more than 2 Snellen lines. Data were collected on baseline demographics, systemic and ocular comorbidities, ocular surgical history, best-corrected visual acuity (BCVA), intraocular pressure (IOP), clinical presentation, eye culture results, and treatments performed. Statistical analysis included the paired t test and odds radio calculations.

MAIN OUTCOME MEASURES

Visual acuity and IOP at final follow-up.

RESULTS

Thirty cases (0.7%) of GDI endophthalmitis were identified among 4073 GDIs performed at the 2 institutions with active follow-up. Device exposure was identified in 20 eyes (67%) on presentation. The average follow-up after presentation was 22.4 ± 25 months. The most frequently identified organism on culture was Streptococcus pneumoniae. Same-day injection of intravitreal antibiotics was the universal first-line therapy. From baseline to final follow-up, the mean BCVA decreased from -0.84 ± 0.77 to -1.30 ± 0.93 (logarithm of the minimum angle of resolution, P = 0.02). Mean IOP did not change from baseline to final visit in the overall cohort (16.2 ± 8.2 mmHg to 14.6 ± 9.4 mmHg, P = 0.30) and in the subgroup that underwent tube explant (15.9 ± 5.5 mmHg to 15.2 ± 10.4 mmHg, P = 0.97). Eighteen of 20 tube exposure cases (90%) underwent tube explant, 1 underwent tube revision, and 1 re-epithelialized.

CONCLUSIONS

Glaucoma drainage implant-associated endophthalmitis was correlated with poor visual outcome. Immediate intravitreal antibiotic delivery was a universal first-line therapy. Tube exposure was a necessary risk factor for late-onset endophthalmitis and required surgical removal or repair.

Managing Ahmed Glaucoma Valve tube exposure: Surgical technique

PURPOSE

To describe a new surgical technique for managing Ahmed Glaucoma Valve tube exposure. The technique is simple, safe, easy to perform and may be an interesting alternative to conventional covering of the tube. This technique allows unlike the classical ones to act on the cause and not only on the complication of extrusion.

MATERIALS AND METHODS

This study was a retrospective case series that included four eyes of four patients who presented with an Ahmed Glaucoma Valve tube exposure.

RESULTS

Surgery was uneventful in all cases and we did not observe any intraoperative or postoperative complications. After at least 1-year follow-up, no case of tube re-exposure was detected.

CONCLUSIONS

Many techniques have been proposed in order to cover the extruded tubes, and different materials may be used to reinforce the coverage, but re-exposure of the tube is a possible scenario. Indeed, our technique attempts not only to cover the exposed tube but also to solve the cause of the extrusion.

Partial thickness cornea tissue from small incision lenticule extraction: A novel patch graft in glaucoma drainage implant surgery

OBJECTIVE

The aim of the present study was to observe the feasibility and effect of cornea slice acquired from femtosecond laser surgery, small incision lenticule extraction (SMILE) as patch graft for the prevention of drainage tube exposure and to compare with the sclera.

METHODS

The research is a prospective comparative randomized study. Patients who received Ahmed glaucoma valve implantation surgery from August 2015 to January 2017 at the Xiamen Eye Center were randomly divided into 2 groups. Group A (corneal group) included 131 cases (135 eyes), receiving the 3 layers of allogeneic cornea slices as graft. Group B (scleral group) included 124 cases (127 eyes), using the sclera as allograft. The appearance, graft, conjunctiva melting, and tube exposure were the primary observation points.

RESULTS

After followed up for 6 to 20 months, a thinner appearance was seen in 3 eyes (2.2%) in the corneal graft group and 7 eyes (5.5%) in the scleral group. Conjunctiva melted and drainage tube exposed in 0 eyes (0%) in the corneal graft group and 2 eyes (1.6%) in the scleral group. One eye needed repair surgery. There was no statistical difference between the 2 groups (P > .05). After surgery, the intraocular pressure was reduced significantly in both groups (P < .05). The white sclera slice could be seen under the conjunctiva, thereby affecting the cosmetic appearance.

CONCLUSION

The cornea slice acquired from SMILE surgery can effectively prevent drainage tube exposure. Moreover, it is easy to acquire, safe, and cheaper, giving the patient a better cosmetic appearance.

Donor sclera versus bovine pericardium as patch graft material in glaucoma implant surgery and the impact of a drainage suture

Purpose

To compare the use of human donor sclera with bovine pericardium as patch graft material for a glaucoma drainage device (GDD), with respect to the incidence of tube exposure, and to study the role of a drainage suture.

Methods

All GDD surgeries between 2010 and 2014 performed at the VU Medical Center were examined in this comparative, retrospective cohort study. A total of 244 cases were included; 163 in the human donor sclera cohort and 81 in the bovine pericardium cohort with a median follow‐up of 31 and 36 months, respectively. The primary outcome measure was occurrence of tube exposure. Survival analysis for tube exposure was carried out and Kaplan–Meier curves compared. Secondary outcomes were postoperative intraocular pressure (IOP), number of glaucoma medications and the effect of a drainage suture.

Results

In the bovine pericardium cohort, eleven (13.6%) eyes developed tube exposure compared to none in the human donor sclera cohort. Their Kaplan–Meier survival curves differed significantly from each other (χ² = 21.1, p < 0.001, log‐rank test). Mean IOP and number of glaucoma medications did not differ significantly between patch graft materials at three months of follow‐up. The use of a drainage suture directly lowered IOP after surgery in both cohorts. Within the bovine pericardium cohort, eyes with a drainage suture experienced more tube exposure, although this difference was not statistically significant (p = 0.09).

Conclusion

Human donor sclera leads to less tube exposure than bovine pericardium. A drainage suture directly lowers IOP after surgery. With bovine pericardium, but not with donor sclera, exposure tends to be enhanced by a drainage suture.

Graft-free glaucoma drainage device implantation: Short tunnel small flap technique

PURPOSE:

To introduce a new technique of short tunnel small flap graft-free glaucoma drainage device implantation and report our early experience.

METHODS:

In a retrospective study, patients with uncontrolled primary open-angle glaucoma underwent short tunnel small flap graft-free Ahmed glaucoma valve implantation. In this technique, plate is sutured 8-10 mm posterior to the limbus and a partial thickness flap is made at 1 or 11 o'clock position, 1 mm posterior the limbus. Tube was passed through a tunnel immediately anterior to the plate into the proximal edge of the flap and then inserted into the anterior chamber via a route underneath the flap. Flap then covered the distal end of the tube and conjunctiva was sutured. Patients were followed for a minimum of 12 months for any sign of tube exposure and rise of intraocular pressure.

RESULTS:

A total of 16 consecutive patients with refractory primary open-angle glaucoma and uncontrolled intraocular pressure were included in this study. Mean age of participants was 59 ± 8.3 years and nine (56%) were male. Mean intraocular pressure at the time of presentation was 26 ± 6.2 mm Hg, which dropped to 16 ± 4.5 at 12 months postoperative follow-up. The number of medications at baseline was 3 ± 1 eye drops, which was decreased to 1 ± 1.2 at 12 months. There were no conjunctival and flap-related complications or any sign of tube exposure during 1-year postoperative period.

CONCLUSION:

Short tunnel small flap graft-free glaucoma drainage device implantation technique combines advantages of both tunneling and flap techniques. Also, it may result in better tube positioning and more favorable cosmetic outcomes.

Efficacy of long scleral tunnel technique in preventing Ahmed glaucoma valve tube exposure through conjunctiva

PURPOSE

To evaluate the efficacy of long scleral tunnel technique used in Ahmed glaucoma valve (AGV) implantation in preventing tube exposure through conjunctiva.

MATERIALS AND METHODS

Patients of adult age, who were unresponsive to maximum medical treatment and underwent AGV implantation, were divided into two groups and investigated retrospectively. Group 1 consisted of 40 eyes of 38 patients that underwent surgery by long scleral tunnel technique and Group 2 consisted of 38 eyes of 35 patients that underwent implantation by processed pericardium patch graft method.

RESULTS

The mean age was 54.8 ± 14.6 years (range 26-68 years) and the mean follow-up duration was 46.7 ± 19.4 months (range 18-76 months) for the patients in Group 1, whereas the mean age was 58.6 ± 16.7 years (range 32-74 years) and mean follow-up period was 43.6 ± 15.7 months (range 20-72 months) for the patients in Group 2 (p > 0.05). In the course of follow-up, tube exposure was detected in one (2.5%) eye in Group 1 and in three (7.9%) eyes in Group 2 (p = 0.042).

CONCLUSION

Long scleral tunnel technique is beneficial in preventing conjunctival tube exposure in AGV implantation surgery.