Our experience of fibrin sealant-assisted implantation of Ahmed glaucoma valve
While I commend the work by Dr Nikhil and team for their innovative use of fibrin glue for scleral patch graft in Ahmed glaucoma valve implantation, I have a few queries and comments.
- The size of the graft stated to have been used was 4–5 mm. I wonder if this size would suffice to achieve a good seal of the patch graft over the tube with fibrin glue as there would be less flat surface for good apposition. A larger graft can overcome this. Scleral patch graft is thicker than Tutoplast used by Kahook and Noecker and one can expect this to get lifted off the tube easily. Please clarify on this.
- The authors discuss about tube blockage, tube cornea touch, conjunctival erosion that are not directly related to the use of glue but failed to mention about patch graft migration. Kindly clarify.
- Was the risk of infection increased due to use of glue on donor scleral graft? This is not mentioned in the article.
- As much more dissection of conjunctiva is required for a shunt versus trabeculectomy, more sutures are required to achieve conjunctival closure. So it would not be unreasonable to use glue rather than sutures, which would definitely reduce the discomfort. The authors explain that conjunctival fibrosis experienced in their cases prevented them from considering glue for conjunctival closure. But in such a situation, even conjunctival suturing would be challenging (can cause buttonholing). At least glue besides apposing the conjunctiva would achieve a good seal and prevent leak. Preventing conjunctival leak is equally important in a shunt procedure. Please comment.
- In scleral thinning as seen in one of the cases with anterior staphyloma, suturing the patch graft would not be a viable option and there, glue outscores. This could be a real indication.
- The authors comment that fibrin sealant-assisted implantation takes less time than sutures. I am afraid this might not be true. The preparation and waiting time for the glue to set in would be similar or slightly more than suturing (four sutures). Please comment.
This is only yet another indication for use of fibrin blue. In the Indian context, use of glue does not give any added advantage but in contrast, only increases the cost of surgery given the fact that implants are expensive. If one plans to use fibrin sealant then it should be utilized for conjunctival closure as well.
1. Choudhari NS, Neog A, Sharma A, Iyer GK, Srinivasan B. Our experience of fibrin sealant-assisted implantation of Ahmed glaucoma valve Indian J Ophthalmol. 2013;61:23–7
© 2013 Indian Journal of Ophthalmology | Published by Wolters Kluwer – Medknow
2. Kahook MY, Noecker RJ. Fibrin glue-assisted glaucoma drainage device surgery Br J Ophthalmol. 2006;90:1486–9