Gelatin sponge insertion into tympanostomy tubes: an in-vitro study to evaluate postoperative obstruction.

To analyze the efficacy of gelatin sponge insertion into lumens of tympanostomy tubes to prevent obstruction in the presence of blood.In vitro model.Absorbable gelatin sponge wicks were placed in the lumen of Ultrasil Collar Button ventilation tubes and Shepherd Grommet ventilation tubes. One half of each group was covered with blood, the other left untreated. Each tube was treated with ofloxacin solution three times daily for seven days. After treatment, the tubes were inspected. Reinspection was performed after brief suctioning. Numerical scores were given based on degree of obstruction.A statistically significant difference in degree of obstruction (P < 0.0001) was seen between all tubes with wicks alone versus those with blood added. After re-evaluation, there remained a statistically significant difference between tubes with wicks alone and tubes with wicks and blood (P < 0.0001).Gelatin sponge insertion does not prevent, and may in fact, enhance, obstruction of pressure equalization tube lumens in the presence of blood.