Long-term effects of Silastic sheeting in the middle ear.

Silastic sheeting is used to restore a mucosally lined middle ear space and to prevent mucosal adhesions between the medial surface of the tympanic membrane and the promontory after surgical procedures involving the removal of middle ear mucosa. To determine the long-term (1.2 to 21.2 years) effects of Silastic sheeting in the middle ear, six temporal bones from patients with permanent Silastic sheeting in the middle ear cavity after single-stage tympanoplasty were examined. In all six bones, no histologic evidence of foreign body reaction, rejection, or chronic inflammation in the middle ear surrounding the silicone sheeting was observed. Furthermore, the middle ear space was lined by normal-appearing, continuous middle ear mucosa. In four temporal bones, there was no evidence of significant submucosal fibrosis. In two bones, significant submucosal fibrosis was attributable to concurrent middle ear disease rather than to the presence of the silicone. It is concluded that Silastic sheeting in the middle ear after single-stage procedures may prevent adhesions between mucosal surfaces. Given eustachian tube function, Silastic promotes a mucosally lined, aerated middle ear cavity without apparent foreign body reaction, rejection, or chronic inflammatory response.