Abstract
The persistence of Hasner's membrane, a thin fragile duplicate of the mucous lining at the end of the nasolacrimal duct, represents the most common cause of congenital dacryostenosis. If the tear flow is blocked tears gather in the lacrimal sac, ultimately resulting in an overflow of this system. Inspissation and bacterial (staphylococcal) invasion of the sac contents lead to infection of the lacrimal sac.
In more than 90% of the newborns, Hasner's membrane perforates spontaneously during the first four to six weeks, in the other children opening is still possible six to 12 months after birth. Based on this knowledge the first step of treatment must be conservative therapy, which is successful in a high percentage of cases: after microbiological examination the application of detumescent and specific antibiotic eyedrops is coupled with digital massage of the lacrimal sac area. If this does not achieve definitive success high pressure syringing according to Bangerter is necessary.
In those cases where irrigation alone cannot open Hasner's membrane (39.1 %), the Bangerter probe is introduced into the nasolacrimal duct and is advanced until the opening of the system to the nasal cavity is reached. In these cases a bicanalicular silicone intubation has to be performed, which prevents restenosis by scarring.
The postoperative long-term results over ten years show a success rate of 98.7% for all treated children. This emphasizes that the above concept of treatment is effective and sufficient.