SAFETY OF SILVER OXIDE-IMPREGNATED SILASTIC TYMPANOSTOMY TUBES

Otorrhea occurs after the insertion of tympanostomy tubes in as many a s 50% of ears. Although topical antibiotic solutions minimize otorrhea in the immediate postoperative period, recurrent otorrhea is sometime s a clinical problem. The antimicrobial effects of silver oxide when i mpregnated into a tympanostomy tube may decrease the incidence of recu rrent otorrhea. This study demonstrates that silver oxide-impregnated silicone elastomer is well tolerated within the middle ear of gerbils when implanted for 1 year, and the tissue reaction is no more than sil icon elastomer without silver oxide. When applied directly to the roun d window of guinea pigs, there was no evidence of ototoxicity of silve r oxide as measured by electrocochleography (N-1 thresholds) and cytoc ochleography (hair cell counts). These animal studies indicate that si lver oxide-impregnated silicone elastomeric tympanostomy tubes may be used safely in clinical trials to determine efficacy.