Abstract
Purpose:
Patients with severe facial burns often suffer indirect damage to their eyes. Burn wound contracture of the periocular skin causes cicitricial ectropion resulting in ocular exposure. With loss of the blink reflex the patient quickly develops exposure keratitis. Due to its anti-inflammatory properties, amniotic membrane has developed into a mainstay of treatment to help maintain the ocular surface prior to skin grafting. However due a host of factors, to include elevated room temperature, desiccation, and inflammatory cytokines in the tear film, the amniotic membrane breaks down rapidly, lasting only 1-3 days. Using our previously reported exposure keratopathy model we have compared cryopreserved amniotic membrane and covalently crosslinked amniotic membrane to evaluated their ability to resist degradation while maintaining the ocular surface of the rabbits.
Methods:
Thirty white rabbits were included in this study. The right eye of each rabbit was subjected to 1.5 cm upper and lower lid blepharoplasty, in addition to excision of the nictitating membrane. The left eyes were untreated to serve as controls. Wounds were treated with polysporin eye ointment for 7 days. After 7 days we sutured a 2x2 cm piece of cryopreserved amniotic membrane or Diimide covalently crosslinked (cryopreserved) amniotic membrane to the conjunctival surface of the eye, covering the cornea, using 16 simple interrupted 9-0 nylon sutures. Clinical examination included fluorescein staining and serial photography on days 3, 5, 7, 14, 21 and 28. The rabbits were returned to the operating room to repair or replace the amniotic membrane whenever exposure to the ocular surface occurred. Rabbits were sacrificed on day 28 and the cornea and conjunctiva were evaluated by histopathology.
Results:
The findings of this study demonstrate that cryopreserved amniotic membrane required more returns to the operating room for repair or replacement in comparison to the crosslinked amniotic membrane. Preliminary histological evaluation demonstrates that there was not a significant difference in the amount in corneal inflammation, neovascularization, or ulceration between the two groups
Conclusions:
Pending future studies on human safety, crosslinking amniotic membrane appears to be a realistic option to extend the treatment time and reduce cost without sacrificing treatment efficacy.
Keywords: 486 cornea: tears/tear film/dry eye •
557 inflammation