Bernard Duchesne

Use of human fibrin glue and amniotic membrane transplant in corneal perforation.

Purpose. To repair corneal perforation using human fibrin glue (HFG) and amniotic membrane transplant (AMT). Methods. Three patients in whom central corneal perforations, approximately 2 mm in diameter, occurred after ocular or systemic disease were successfully cured using HFG and AMT. The technique consists first of using a high-viscosity sodium hyaluronate viscoelastic material to restore anterior chamber depth followed by a debridement of the ulcer. The perforation site is filled with the HFG to corneal surface level. The so-formed plug is then secured with an AMT to avoid its extrusion. An extended-wear bandage contact lens and topical antibiotics were used in these patients for 3 weeks. Results. Total reepithelialization was observed after an average of 15 postoperative days. The AMT dissolved within 8 weeks to uncover a whitish scar formed within the perforation sites. No complications were observed in any patients. After a follow-up period of 195–325 days, all corneas remained stable; there was no infection or ulcer recurrence, but some corneal scar thinning was observed in all three cases. Conclusion. The described surgical approach using HFG and AMT allowed a successful repair of corneal perforations with a diameter of 2 mm associated with significant loss of stroma. This method may be a good alternative to delay penetrating keratoplasty for treating corneal perforations, especially in acute cases in which graft rejection risk is high.

Corneal preparation of eye bank eyes for experimental surgery.

Purpose. To evaluate the efficacy of dextran in balanced salt solution (BSS) as a preparation of eye bank corneas for experimental surgeries. Methods. We used 12 eye bank eyes that were unsuitable for transplant. The corneas were removed from the globe and affixed to a Hanna artificial anterior chamber. Four concentrations of dextran–BSS (10%, 15%, 20%, and 30% [± 0.56%]) were used to dehydrate the corneas, and corneal thickness was assessed with an ultrasonic pachymeter (±5 &mgr;m) at varying time-intervals over 3 hours. Results. The corneas were thinned to an average thickness of 477 ± 54 &mgr;m, 430 ± 54 &mgr;m, 406 ± 61 &mgr;m, and 391 ± 52 &mgr;m at average times of 75 ± 0 minutes, 85 ± 23 minutes, 60 ± 12 minutes, and 45 ± 0 minutes for the 10%, 15%, 20%, and 30% concentrations, respectively. Corneal thickness was stabilized in both a 15% and a 20% solution. The data was fit to exponential curves until a minimum value was reached, after which linear regression analysis was used to determine the slopes of the data. The slopes for the 15% and 20% concentrations were not significantly different from 0 (p = 0.5 and p = 0.4, respectively). The slopes for each set of data from the 10% and 30% concentrations were significantly different from each other (p = 0.010 and p = 0.001, respectively). Conclusions. A solution of 20% dextran in BSS is effective for dehydrating eye bank corneas to a quasi-normal physiologic thickness and for maintaining the thickness for a sufficient amount of time. Both the posterior and anterior sides of the cornea should be exposed to the solution for 60 minutes.

Eine neue, nicht penetrierende synthetische Hornhaut

ZusammenfassungBei penetrierenden Keratoprothesen (KPro) kommt es häufig zu postoperativen Komplikationen die bis zum Verlust des Auges führen können. Um diese Komplikationen zu verringern, wurde eine neue supradescemetsche, nicht penetrierende, Keratoprothese entwickelt.Sie wird durch eine zirkuläre Schürze, die intrastromal verankert wird, befestigt, und liegt auf der Descemet Membran auf. Vier verschiedene biokompatible Polymere wurden in Augen von Hasen (NZW) implantiert. Dazu wurde eine neue Delaminationstechnik und Trepanation entwickelt. In acht Augen wurde je eine KPro (2X PMMA, 2X Hema-NVP, 2X Hema-MMA und 2X Hema-EMA) implantiert. Der postoperative Verlauf war komplikationslos, die Prothesen blieben klar und in situ und erlaubten einen ausgezeichneten Einblick in den Fundus. Die Nachbeobachtungszeit von einem Monat ist jedoch zu kurz um über die Stabilität und den Einsatz dieser KPro für den humanen Gebrauch zu entscheiden.SummaryPostoperative complications of transcorneal fixated keratoprosthesis (KPro) are frequent and severe and may lead to the loss of the eye. To avoid these problems, a novel supra-Descemetic, non penetrating mesoplant was developed. It is locked in place by an annular skirt and is placed over Descemet’s membrane. Four different biocompatible polymers were implanted in eyes of New Zealand white rabbits (NZW). A new delamination and trephination technique was developed.In 8 eyes the new KPro (2X PMMA, 2X Hema-NVP, 2X Hema-MMA and 2X Hema-EMA) were implanted. There were no postoperative complications, the KPros stayed clear and in place and allowed an excellent view of the fundus. The follow-up of one month is nevertheless too short to determine stability and possible use of this new KPro in humans.

Le carcinome de Merkel

Le carcinome de Merkel est une tumeur cutanee d’origine neuroendocrine, derivee des cellules neurotactiles. Nous rapportons un cas de carcinome de Merkel decouvert chez une patiente âgee de 77 ans, chez qui le diagnostic a ete pose sur base d’une biopsie. Nous profitons de la description de ce cas pour presenter une tumeur rare mais agressive, en insistant sur les methodes diagnostiques et sur les differents types de traitements envisageables.

Surface-modified porous PTFE for keratoprostheses: Biocolonization in the rabbit cornea

The purpose is to assess intracorneal biocolonization of expanded polytetrafluoroethylene materials covalently coated with collagen type-I.