The "Pull-Through" Suture; Facilitating Watertight Anterior Chamber Entry and Minimizing Early Hypotony in Glaucoma Tube Surgery

A Novel Tube Insertion Technique for Glaucoma Drainage Device Implantation

PURPOSE

Early hypotony after non-valved glaucoma drainage device (GDD) implantation for complex glaucomatous eyes with labile aqueous production can lead to significant visual morbidity. We therefore sought to report the early postoperative outcomes of a novel surgical technique that allows atraumatic insertion of non-valved GDDs through a much smaller 25-gauge scleral track, to minimize entry site leakage and improve safety.

METHODS

Retrospective case series of 15 consecutive cases undergoing non-valved GDD insertion into the anterior chamber using a previously unreported technique.

RESULTS

All eyes underwent successful GDD insertion using our novel technique, with no intraoperative complications. The mean preoperative intraocular pressures (IOP), at day 1, week 1 and week 3 were 31.4, 22.4, 23.7, and 25.6 mm Hg, respectively. A statistically significant IOP reduction was achieved at day 1, week 1 and week 3 postoperatively ( P <0.05) without any observed leakage at the scleral entry site. One eye (6.7%) with complex panuveitic glaucoma developed early hypotony (5 mm Hg) with shallow choroidal detachments on day 1. This was successfully managed with 1 intracameral ophthalmic viscoelastic device injection given at the slit-lamp and no further intervention.

CONCLUSIONS

This novel single needle-docking intraocular insertion manoeuvre is an easily adoptable technique to make GDD insertion through a smaller 25-gauge water-tight scleral track more efficient and less traumatic. The technique reduces scleral distortion and therefore improves surgical safety particularly in eyes with complex secondary glaucoma.

[Glaucoma Drainage Devices - Evaluation of Surgical Modifications to Avoid Postoperative Complications]

BACKGROUND

In glaucoma therapy, there are many treatment options, such as glaucoma drainage devices (GDI). The aim of this study is to compare postoperative outcomes after using different surgical techniques.

MATERIAL AND METHODS

269 eyes of 250 patients who received a GDI at the ophthalmological center at the university hospital in Cologne between February 2010 and September 2016 were included in this study. The patients' baseline parameters were collected: age, sex, intraocular pressure, visual acuity, glaucoma medication, diagnosis, operated eye (right or left), number of previous eye surgeries (including laser therapy), duration-of-stay at the hospital as well as all glaucoma complications and complication-related reoperations.

RESULTS

The mean individual pressure reduction was 39, 42 and 46% after 6, 12 and 24 months respectively, while the use of medication was reduced by 38, 42 and 50%. The success rates after 1 to 5 years was 75, 60, 57, 50 and 37% with a median survival of 48 months. 86 eyes (32%) experienced early complications and 156 eyes (56%) experienced late complications. 52% of the eyes (n = 139) had to be re-operated. The technique of creating a track to enter the anterior chamber had statistically significant influence on the early postoperative hypotony (p < 0,001). Fibrin glue had no influence on early hypotony. In the univariate analysis of early postoperative hypertension requiring paracentesis, the implant type (p = 0,009), tracking-technique with a paracentesis knife or a 22-gauge needle (p = 0,004), the occlusion method (p = 0,001) and the application of viscoelastics (p = 0,001) were statistically significant parameters. If GDI were implanted as a second implant, significantly more conjunctival erosion was recorded (p = 0.040).

CONCLUSION

The use of a 22-gauge needle entering the anterior chamber reduces the hypotony risk when compared to fibrin glue. That risk is not increased by adding venting slits. When implanting GDI as a second implant, the higher risk of conjunctival erosion should be considered.