Comparison of conjunctiva-related complications between scleral and corneal patch grafts in Ahmed glaucoma valve implantation

Abstract

Purpose: Comparison of the conjunctiva related complication rates and success rates among eyes with Ahmed glaucoma valve (AGV) implantation in which eye bank derived scleral and corneal patch grafts had been used to cover the tube. Methods: Retrospective comparative study. Patients who underwent AGV implantation between January 2000 to December 2016 were included. Demographic, clinical data, intra and post operative data was obtained from electronic medical records. Conjunctiva related complications were divided into two groups: with and without implant exposure. Conjunctiva related complication rates, success rate, risk factors among eyes with corneal and scleral patch graft were compared. Results: Three hundred and twenty three eyes of 316 patients underwent AGV implantation. Scleral patch graft was used in 214 eyes of 210 patients (65.9%) and corneal patch graft was used in 109 eyes of 107 patients (34%). Median follow up was 14 months. There was no significant difference in the conjunctiva related complication rate (7.3 % in corneal patch graft versus 7.0% in scleral patch graft;p=0.5) and conjunctival dehiscence rate (3.7% versus 4.6%, P = 0.7) among the two groups. Success rate was significantly higher in the corneal patch graft group versus the scleral patch graft group (98% versus 72%; p=0.001). Eyes with corneal patch graft had a higher survival rate ( P = 0.01). Conclusion: There was no significant difference in the rate of conjunctiva related complications following corneal and scleral patch grafts used to cover the AGV tube. Eyes with corneal patch graft had a higher success rate and survival rate.

Scleral Grafts in Ophthalmic Surgery. A Review

“…V roce 1987 publikoval Fredman možnost prevence extruze Moltenovy chlopně za pomoci překrytí sklérou [142], což je dodnes v případě krytí glaukomových implantátů běžně používaná metoda, kterou v různých variacích publikovali i další autoři [143][144][145][146][147][148][149][150][151][152][153][154]. Lam obdobným způsobem popsal krytí Ahmedovy chlopně [143], Aslanides navrhl v této indikaci využití autologní skléry z důvodu lepší dostupnosti [144] a Zeppa publikoval modifikaci s fixací skléry za pomocí tkáňového lepidla [155].…”

“…Další materiály, které byly úspěšně použity při krytí glaukomových implantátů, jsou perikard [145,148,150,[156][157][158][159], dura mater [145,146], rohovka [152,154,156,157,160,161], tragální perichondrium [162], kolagenový implantát Ologen [163], fascia lata femoris [157] nebo amniová membrána [157,158]. Případně lze implantát zavést do sklerálního tunelu, kdy není potřeba žádný další krycí implantát [151,157,164,165].…”

New approach to AGV implantation with scleral tunnel method by prolene suture: Şimşek Technique

“…3,4 Tube exposure not only results in ocular inflammation and exacerbation of physiological conditions but also significantly increases the risk of late endophthalmitis by allowing microorganisms to enter the anterior chamber from the ocular surface 5,6 Although there is no consensus on surgical techniques to prevent tube exposure, various approaches have been employed, including the use of scleral flaps, tenon advancement and duplication, pericardium, fascia lata, lyophilized sclera, dura mater, amniotic membrane, cornea, and cellular dermis grafts. [7][8][9][10][11][12][13][14][15] Another technique involves the implantation of the AGV tube by creating a long scleral tunnel using a Crescent blade or a 22 G needle. 1,[15][16][17][18][19][20][21] The objective of this study was to present the short-term results of AGV implantation technique, which utilizes a suture-asissted long scleral tunnel, with the aim of preventing conjunctival tenon erosion caused by the AGV tube.…”

Commentary: Do not judge a tube by its cover

“…The authors of the study published herein have compared donor SPG and CPG in Ahmed glaucoma valve (AGV) surgery and have found no difference in the rate of conjunctival dehiscence or tube/plate exposure. [ 5 ] However even though the rate was not statistically significant, there was a clinically relevant difference in the number of eyes that developed plate exposure: a devastating complication which can lead to a high rate of explantation as success rate of management can be variable. Plate exposure was much higher in the SPG group ( n = 6) compared to one in the CPG group.…”

“…The authors[ 5 ] report increasing age as the sole significant risk factor responsible for conjunctival complications, whereas there are other reports that have found young age (and inflammation) as significant risk factors. [ 6 ] Other risk factors like increased number of prior surgeries and inferior implantation were not found to be significant, whereas other authors have.…”