Comparaison des résultats anatomiques et fonctionnels à 12 mois d’une série de kératoplasties lamellaires profondes assistées au laser femtoseconde Z6 versus trépanation manuelle pour kératocônes sévères

Abstract

The management of severe keratoconus requires corneal transplantation, for which the gold standard is deep anterior lamellar keratoplasty (DALK), preserving the healthy Descemet's membrane and endothelium. The safety and reproducibility of corneal cuts have been improved by the evolution of femtosecond lasers in refractive surgery, and femtosecond laser in DALK would seem to provide the same advantages over the manual method. In our retrospective study, we compare functional and anatomical results of femtosecond assisted DALK versus manual trephination DALK in patients with keratoconus in stage 4of the Krumeich classification. It is a retrospective study including all patients with stage 4keratoconus who underwent femtosecond laser assisted DALK between November 2012and November 2015in Nantes hospital. We compared those patients to a group of patients who underwent manual DALK in the same period, paired by age and maximal keratometry. We assessed visual acuity, pachymetry, endothelial cell density (specular microscopy), and keratometry before surgery and at 4, 8and 12months of follow-up. Laser settings and intraoperative complications were recorded. Nineteen patients underwent surgery by femtosecond assisted DALK, 6women and 12men with average age 30.2±10.8years at transplantation. They were paired with a group of 17patients who underwent manual DALK in order to compare results. Before surgery, mean visual acuity in the femtosecond group was 0.90logMAR versus 0.89logMAR in the manual group, showing no statistically significant difference (P=0.96). Both groups were similar in terms of preoperative age, mean keratometry, pachymetry and endothelial cell density. Average visual acuity post-surgery was 0.27, 0.26; and 0.14logMAR for femtosecond DALK versus 0.27, 0.17et 0.25for manual DALK at 4, 8and 12months follow-up, respectively showing no statistically significant difference. After surgery, at 4, 8and 12months, mean pachymetry was similar in both groups, and average endothelial cell density was 2390cells/mm2in femtoDALK versus 2531cells/mm2in manual DALK at 12months of follow-up, showing no statistically significant difference (P=0.5726). The rate of Descemet's membrane microperforations during the procedure was low and similar for both groups. Our study allows for a 12month follow-up, with assessment of visual recovery, anatomical result and endothelial safety in a sample of 19femtosecond laser assisted DALK with no statistical significant difference versus the manual trephination group. Femtosecond laser allows for increased reproducibility of the DALK procedure without reducing adverse effects during surgery. Femtosecond laser seems to improve the technique of the DALK procedure, and future developments could improve the reproducibility of DALK even further. A medical economics study would be necessary to determine the cost effectiveness of femtosecond laser assisted DALK.