Differential penetration of ototopicals and water through tympanostomy tubes

Objective. To evaluate the penetration of ototopicals and water through tympanostomy tubes (TT) using a physical model. Study Design. An in vitro model was created to measure the ability of various solutions to penetrate a variety of TT. Methods: A TT was placed through a perforation (myringotomy) in a silastic sheet (tympanic membrane) fixed between the ends of two 1 mL syringes. Measurements were obtained of the maximum height various liquids (tap water, 2% soapy water, ocean water, ofloxacin otic, corticosporin otic, and ciproftoxacin/dexamethasone otic) achieved before penetrating different TTs (1.0 mm or 1.27 mm Paparella silicone, 1.14 nun or 1.27 mm Reuter Bobbin titanium, 1.27 nun Collar Button fluoroplastic or 1.14 mm T-type silicone). Results: Two percent soapy water was significantly more permeable than water and ocean water in all tubes studied. Ciproffoxacin/dexamethasone otic was significantly more permeable than tap water, ocean water, and oftoxacin otic in only the Collar Button fluoroplastic TT. Our results suggest that titanium TTs are more permeable than other TT. Otherwise, ototopicals, tap water, and ocean water behaved similarly across all TT studied. Conclusions. Our results demonstrate that ototopicals, tap water, and ocean water behave similarly with regard to TT penetration. Ciproffoxacin/dexamethasone otic may have better penetration than other ototopicals. Titanium TT may be easier to penetrate than other TT. Key Words. Tympanostomy tubes, otorrhea, ototopicals, water precautions, differential penetration.