Surface reaction on silicone tubes used in the treatment of nasolacrimal drainage system obstruction

Silicone tubes removed from patients who underwent intubation of the nasolacrimal system for acquired or congenital obstruction were studied to determine the cellular reaction on the tubes and to assess the relationship between the length of intubation and the cellular response. Twenty-one tubes were available for analysis. Length of intubation varied from 39 to 415 days; patient ages varied from 10 months to 75 years. All patients had undergone dacryocystorhinostomy or closed intubation of the nasolacrimal system. No patient had clinical signs of infection at the time of tube removal. All tubes were mounted on glass slides and stained with hematoxylin and eosin. The reactions seen, together with the location and type of cells present, were graded by a masked observer. There were varying numbers of inflammatory cells, predominantly polymorphonuclear leukocytes. As the length of intubation increased, the number of inflammatory cells also increased. The proximal portion of the tubing showed the least amount of cellular reaction at all lengths of intubation.