Pseudochamber-Protected Keratoplasty (PPK) with a New Inter-Corneal Surgical Device Implant Technique in High-Risk Cases

Abstract

Background/Objectives: To describe the pseudochamber-protected keratoplasty (PPK) procedure with the new Endo-K Pro® implant technique and report the clinical outcomes in patients at high risk for penetrating keratoplasty (PKP). Methods: This case series study included patients who required a PKP and had a high risk for corneal transplant failure. All cases underwent the PPK procedure with simultaneous Endo-K Pro® implantation and had a minimum follow-up of 12 months. Graft survival was the primary outcome (defined as a clear graft with an endothelial cell density >500 cells/mm2). Central corneal thickness (CCT), corrected distance visual acuity (CDVA), intraocular pressure (IOP), and complication rate were the secondary outcomes. Results: Twenty-five eyes (twenty-five patients) were included. The mean follow-up was 23.64 ± 8.2 months (range: 12-36 months). Graft survival was achieved in 23 of the 25 cases (92%). One eye had to be re-transplanted due to persistent oedema secondary to uncontrolled IOP. In two cases (8%), the graft failed three months after surgery when an anterior pseudochamber collapsed due to direct contact of donor endothelium and host tissue. Six eyes experienced host tissue protrusion that was successfully managed using an Nd: YAG laser (two eyes) or injecting a cohesive viscoelastic into the pseudochamber (four eyes). CDVA increased significantly during the follow-up period. No significant changes were found in IOP. No intra- or postoperative complications were reported. Conclusions: PPK with the Endo-K Pro® implant seems to be an effective and safe surgical approach as an alternative in high-risk patients for PKP, allowing full-thickness corneal transplantation without performing an open-sky procedure.