TYMPANOSTOMY TUBES AND WATER EXPOSURE - A PRACTICAL MODEL

Objective: To determine whether water exposure causes middle ear conta mination in patients with collar button tympanostomy tubes (TTs). Meth od and Design: An in vitro model of a human head that contained an aur icle, external auditory canal, tympanic membrane with TT, middle ear, eustachian tube, and mastoid cavity was developed. Two electrodes conn ected to an external ohmmeter resided in the middle ear to detect wate r entry. The model was tested with 4 types of water exposure: showerin g, bathing, hair rinsing, and swimming. Statistical analysis was perfo rmed by the Fisher exact test. Main Outcome Measures: A positive test result corresponded to water entering the middle ear via the TT, confi rmed by a resistance reading of zero on the ohmmeter. A negative test result indicated no change in the initial high resistance reading. Res ults: No positive test results were obtained for showering (0 of 60 te sts), hair rinsing (0 of 60 tests), or head submersion (12.7 cm) in cl ean tap water (0 of 60 tests). Ten positive test results were obtained for head submersion in soapy water (10 of 97 tests), which was statis tically different from clean water (P less than or equal to.007). Swim ming pool depths of 30, 45, 60, and 75 cm elicited positive test resul ts in 2 of 16, 3 of 18, 2 of 20, and 11 of 20 tests, respectively. A h igher incidence of water entry into the middle ear occurred at depths of more than 60 cm (P less than or equal to.001). No statistical diffe rence between depths of 60 cm or less occurred (P=.88). Conclusions: S howering, hair rinsing, and head submersion in clean tap water do not promote water entry into the middle ear. Submersion in soapy water inc reases the probability of water contamination. Pool water infrequently enters the middle far with head submersion, but the incidence increas es with deeper swimming (>60 cm). These data provide further evidence that many water precautions frequently advised in patients with TTs ar e unnecessary.