Evaluation Of The Grosso® Implant And Related Minimally Invasive Surgical Procedure For The Treatment Of Keratoconus And Other Corneal Ectasias.
Published 2024 - 42nd Congress of the ESCRS
Reference: PP23.15 | Type: Free paper | DOI: 10.82333/j28v-3305
Authors: Edoardo Grosso* 1 , Neil Lagali 2 , Maria Xeroudaki 3 , Graziana Maria Ragonese 4 , Diego Gallo 4 , Letizia Mansutti 5 , Moses Kakanga 5 , Emiliano Lepore 5
1Studio Oculistico Grosso,Turin,Italy, 2Biomedical and Clinical Sciences, Linköping University,Linköping,Sweden, 3Ophthalmology, Linköping University Hospital,Linköping,Sweden, 4Politecnico di Torino,Department of Mechanical and Aerospace Engineering,Turin,Italy, 5Recornea s.r.l.,Trieste,Italy
Purpose
The GROSSO® implant is a net-like corneal implant made of nitinol and designed to treat corneal ectasias, in particular keratoconus. The device is intended to reshape the cornea in order to restore its physiological curvature pattern, so as to improve visual acuity and contrast sensitivity. We set out to determine the technical feasibility of surgical implantation of the device. First, safety was investigated through computational models. Secondly, ex vivo tests on pig eyes and an in vivo rabbit trial were carried out. Implants were positioned into animal eyes using human standard-of-care femtolaser-assisted surgery. The procedure was feasible to implement with standard instrumentation and the learning curve was rapid.
Setting
PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino
Recornea srl, Trieste, Italy
Faculty of Medicine, Linköping University, Sweden, in a licensed facility for surgery and postoperative care.
Methods
The GROSSO® implant has a circular reticular structure (diameter 8 mm, thickness 60 µm, curvature 43 D). Validated numerical simulations were carried out in Abaqus to virtually predict the mechanical performance of the implant during surgery. In one eye of 20 rabbits, a round pocket of 9.5 mm diameter was created by femtosecond laser at depth 2/3 of the minimum corneal thickness. 12 eyes received the implant, 8 formed the control group. The implant was kept folded with a 6-0 vicryl stich, inserted into the corneal pocket through a 4 mm side incision and atraumatically unfolded inside. Longitudinal eye examinations at 1 week, 1, 2, 3 and 6 months postop were conducted to evaluate the effects on tissues and any possible complications.
Results
Computational simulations showed that the GROSSO® implant is mechanically stable with no risk of permanent deformations caused by the bending during surgery. No closing corneal sutures were used as the intra-stromal location and small access cut were sufficient to ensure the implants remained in place within the stromal pocket. OCT showed excellent adhesion of the two corneal layers to the implant, as confirmed by attempts at surgically removing implants after 6 months. Some pocket decentering occurred in most rabbit eyes, due to the impossibility to perform optimal suction on the sclera. That may explain some degree of neovascularization observed in some eyes, in which the pocket or the incision lied next to the limbus.
Conclusions
The GROSSO® implant exhibited a promising safety profile, and feasibility of implementation in animals. It was easily placed into the corneal stroma through standard femto laser-assisted surgical technique. It effectively recovers its shape after insertion and transfers to the cornea its enhanced mechanical properties. The GROSSO® implant will enter the first in-human study in 2024.