Comparison of visual outcomes and complications of Boston Kpro type 1 and fascial augmented OOKP and OKP
Authors: Alison K. Banwell 1, Jacob Cook2, Luke Northey3, Gregory Moloney3. 1Queen's University, 2New South Wales Ministry of Health, 3University of British Columbia.
Author Disclosures: A.K. Banwell: None. J. Cook: None. L. Northey: None. G. Moloney: All other investments or relationships that could be seen by a reasonable, well-informed participant as having the potential to influence the content of the educational activity; Name of for-profit or not-for-profit organization(s); Johnson and Johnson, Kowa. All other investments or relationships that could be seen by a reasonable, well-informed participant as having the potential to influence the content of the educational activity; Description of relationship(s); Consultant, Consultant
Abstract Body:
Purpose: To report intermediate-term visual outcomes and retention rates of patients undergoing Boston keratoprosthesis type 1 (B-Kpro), osteokeratoprosthesis (OKP), and osteoodontokeratoprosthesis (OOKP) in Sydney, Australia.
Study Design: Retrospective consecutive non-comparative interventional case series.
Methods: A retrospective chart review was performed of patients that underwent B-Kpro, OKP, and OOKP implantation from September 2014 to November 2020. OKP and OOKP patients underwent a multi-staged surgery. Stage 1 involved ocular surface preparation with implantation of a buccal mucosal graft coupled with a temporalis fascial flap. During this stage an osteoodontal lamina (OOKP), or in edentulous patients, an osteocalvarial lamina (OKP) was harvested, optical cylinder inserted, and the device implanted under the orbicularis muscle. Stage 2 involved retrieving the lamina, corneal trephination, and implantation of the keratoprosthesis. Augmentation of the OOKP with a temporalis fascial flap was performed to reduce dental lamina resorption. This is a novel modification to the OOKP technique.
Results: During the study period 10 eyes underwent B-Kpro surgery, five eyes OOKP, and one eye OKP. Mean follow up duration was 32.1 months (range 6-67 months). Kaplan-Meier curve analysis showed 70% probability of B-Kpro retention at 60 months and 100% probability of OOKP retention at 40 months. The OKP patient exenteration at 20 months due to invasive basal cell carcinoma. In the B-Kpro group visual acuity improved from mean of 2.21 logMAR pre-operatively to 1.12 post-operatively (P<0.05). In the OKP and OOKP group visual acuity improved from mean of 2.37 LogMAR pre-operatively to 0.33 LogMAR post-operatively (P<0.001).
Conclusions: This preliminary data represents a small cohort in a low volume service centre which covers a large catchment area. In this complicated patient cohort intermediate-term anatomical retention rates of B-Kpro and OOKP were satisfactory, and the novel fascial flap appears to be promising as a possible method to reduce bone resorption and prolong survival rates of the OOKP. The majority of patients benefited from visual acuity improvement following their respective interventions.
