Comparative study between the use of Injectable Cross-Linked Hyaluronic Acid and mitomycin c in Trabeculectomy surgery

Abstract

SUMMARY A t present, trabeculectomy is still the most widely used surgical procedure to treat glaucoma; the procedure entails opening a gaurded fistula between the eye’s anterior chamber and the subconjunctival space, thus generating a subconjunctival reservoir for fluid or filtering bleb. Failure of the filtering bleb can occur at various times after a trabeculectomy, mostly due to development of fibrosis in the conjunctiva and episclera because of progressive fibroblast proliferation and collagen deposition at the site of the filtration bleb, leading to poor postoperative intraocular pressure control with subsequent progressive optic nerve damage. Hyaluronic acid has haemostatic and anti-inflammatory properties and can be used as a placeholder. However the usual commercially hyaluronic acid products which are used in cataract surgery are absorbed within a short time (few days). The cross-linked (reticulated) hyaluronic acid products which are used for cosmetic applications, on the other hand, are absorbed less rapidly. HealaFlow® is a cross-linked form of sodium hyaluronate providing a slowly resorbable injectable viscoelastic implant that can be used for both non-perforating glaucoma surgery; as in standard deep sclerectomy, As well as in penetrating glaucoma surgery; were it can be injected under the sclera flap and the conjunctiva during trabeculectomy surgery, acting as space filler and limiting the postoperative fibrosis. The aim of this study is to evaluate the efficacy and safety of injection of cross linked hyaluronic acid below the scleral flap and under the conjunctiva in trabeculectomy surgery compared to trabeculectomy with mitomycin C. The present study was conducted on twenty four eyes (fifteen patients) with primary open angle glaucoma, between december 2011 and August 2014 in Ain Shams University Hospital, patients were followed up for 9 months. The study population was divided into two comparative groups; a group of 12 eyes undergone a standardized trabeculectomy augmented by Healaflow and a group of 12 eyes undergone a standardized trabeculectomy augmented by MMC. During the follow up, patients were monitored and evaluated for 9 months by; measuring the IOP and clinical assessment of bleb morphology at day one post-operative then 1week, 1 month, 3 months, 6 months and 9 months also UBM was done for the bleb height and internal reflectivity at 1 month, 3 months, 6 months and 9 months postoperative with documentation of any associated complications. The surgical success was defined as following: Complete success if the IOP is ≤21 mmHg without antiglaucoma medication. Qualified success if the IOP is ≤21 mmHg with antiglaucoma medication. If the preoperative IOP is ≤21 mmHg a post-operative reduction of 20% or more of the preoperative IOP is considered success. This study revealed the following results: There was No significant difference between both of our study groups regarding preoperative and postoperative IOP levels and IOP reduction rates (IOPR%), however, the Mitomycin C group had a slightly higher success rates than the Healaflow group but it was statistically non-significant. Also we found no statistically significant difference between both of our study groups regarding the bleb extent, vascularity and height. However, the bleb in the MMC group showed slightly more favorable morphological features than in the Healaflow group. Our study showed that the UBM bleb height was non-significantly higher in group Mitomycin c than Healaflow at 3, 6 and 9 months follow ups. The internal reflectivity of the bleb was assessed by UBM postoperatively with no significant difference between both of our study groups throughout the follow up.