This study aims to compare the success rate of external dacryocystorhinostomy with and without amniotic membranes in patients with nasolacrimal duct obstruction.

Naso-lacrimal duct obstruction (NLDO) causes epiphora, recurrent dacryocystitis, and skin fistulas. Its incidence increases with age. Dacryocystorhinostomy (DCR) is considered the standard treatment for NLDO. Authors describe similar success rates between external or endoscopic approaches. The former uses a skin approach, through which an osteotomy is made, allowing access to the lacrimal sac and subsequently to the middle meatus of the nasal cavity. On the other hand, endoscopic surgery uses an endonasal route to create a fistula towards the lacrimal sac, with the benefit of not generating visible scars in patients. The success of both surgeries depends on creating a wide osteotomy and the preservation of the mucosa around it, reducing the risk of scarring and stenosis of the ostium formed.

Some authors suggest that limiting the inflammatory process localized to the osteotomy may improve the surgical success rate. The use of mitomycin C (MMC) has been reported, with limited results due to variability in the concentration and methods of drug used.

Amniotic membrane (AM) has been used in ophthalmology, such as in pterygium surgery, chemical trauma, and inflammatory diseases of the ocular surface. In these contexts, AM limits the inflammatory response, promotes re-epithelialization, and reduces fibrosis. AM epithelial cells do not express HLA-A, B, C, or DR antigens on their surface, and therefore do not present a risk of rejection by the immune system.

This study aims to compare the success rate of external DCR with and without amniotic membranes in patients with NLDO.

Inclusion Criteria:

• Patients over 18 years old
• Diagnosis of Nasolacrimal Duct Obstruction or Score ≥ 2 on the Munk Scale
• Patients able to undergo general anesthesia
• Patients able to keep follow-up
• Patients willing to participate in the study and signed informed consent

Exclusion Criteria:

• Patients with ocular surface diseases that affect surgical outcomes, such as blepharitis, lacrimal punctum epithelization, kissing punctae, facial nerve palsy, allergic conjunctivitis, etc
• Patients with eyelid malpositions
• Patients diagnosed with systemic inflammatory diseases, such as granulomatosis with polyangiitis, sarcoidosis, etc
• Previous history of facial trauma with nasal bone fractures
• Pregnancy and lactation