Injectable in situ cross-linking hyaluronan hydrogel for easier removal of posterior vitreous cortex in vitrectomy

Purpose: Removing transparent vitreous tissues, such as a residual vitreous cortex (VC) or proliferative membrane, without damaging the retina is often problematic in vitrectomy. We examined the feasibility of an injectable in situ cross-linking hyaluronan hydrogel (XL-HA) for vitrectomy. Study design: Experiments using ex vivo and in vivo animal models. Methods: HA-dibenzocyclooctyne and HA-azidoethylamine solutions were mixed to form XL-HA, which then gradually formed a hydrogel. We tested the function of XL-HA in ex vivo porcine eyes. We then examined the performance of XL-HA in in vivo rabbit models of posterior vitreous detachment, posterior VC removal, and proliferative vitreoretinopathy. Results: The ex vivo study showed that XL-HA rapidly embedded triamcinolone acetonide, mimicking VC attached to the retina, and became hard enough to be pinched with tweezers within 3 minutes, allowing us to remove only the triamcinolone acetonide without impairing the internal limiting membrane. In the in vivo rabbit models, XL-HA injection improved posterior vitreous detachment, and the thin and fragile posterior VC or fibrous proliferative membrane was readily peeled off without any damage to the underlying retina as compared with untreated controls. A short-term intraocular biocompatibility test demonstrated that the intraocular pressure remained normal with XL-HA injected into the eye. In addition, transmission electron microscopy showed no obvious abnormalities in the cornea or in the inner and outer retina. Conclusion: The results indicate that XL-HA is a potential adjunctive device to help make vitrectomy safe, effective, and successful.