Effect of Graft Size on Air-bone Gap Closure in Cartilage Button Tympanoplasty.

OBJECTIVE: To study the effect of graft size on postoperative air-bone gap in children undergoing butterfly inlay cartilage tympanoplasty using circular punch grafts. STUDY DESIGN: Retrospective case review. SETTING: Tertiary, academic children's hospital. PATIENTS: Children less than 16 years old undergoing circular butterfly inlay tympanoplasty using 4, 5, or 6 mm round grafts. INTERVENTION: Butterfly inlay tympanoplasty using circular punch graft harvest technique. MAIN OUTCOME MEASURES: Postoperative pure-tone average and air-bone gap. RESULTS: Fifty-two children were included in the analysis: 18 in the 4 mm group, 28 in the 5 mm group, and 6 in the 6 mm group. There was no significant difference in either postoperative pure-tone average or air-bone gap among the three groups. Closure rates for the 4, 5, and 6 mm graft groups were 94, 96, and 67%, respectively, for an overall rate of 92%. CONCLUSIONS: Cartilage button butterfly inlay tympanoplasty with punch graft is an effective method for tympanic membrane repair with similar hearing results among various graft diameters but may have diminished success with perforations requiring grafts larger than 5 mm. Larger case series are necessary to determine if larger defects are best managed with other repair techniques.

Continuous droplet removal upon dropwise condensation of humid air on a hydrophobic micropatterned surface.

Combination of two physical phenomena, capillary pressure gradient and wettability gradient, allows a simple two-step fabrication process that yields a reliable hydrophobic self-cleaning condenser surface. The surface is fabricated with specific microscopic topography and further treatment with a chemically inert low-surface-energy material. This process does not require growth of nanofeatures (nanotubes) or hydrophilic-hydrophobic patterning of the surface. Trapezoidal geometry of the microfeatures facilitates droplet transfer from the Wenzel to the Cassie state and reduces droplet critical diameter. The geometry of the micropatterns enhances local coalescence and directional movement for droplets with diameter much smaller than the radial length of the micropatterns. The hydrophobic self-cleaning micropatterned condenser surface prevents liquid film formation and promotes continuous dropwise condensation cycle. Upon dropwise condensation, droplets follow a designed wettability gradient created with micropatterns from the most hydrophobic to the least hydrophobic end of the surface. The surface has higher condensation efficiency, due to its directional self-cleaning property, than a plain hydrophobic surface. We explain the self-actuated droplet collection mechanism on the condenser surface and demonstrate experimentally the creation of an effective wettability gradient over a 6 mm radial distance. In spite of its fabrication simplicity, the fabricated surface demonstrates self-cleaning property, enhanced condensation performance, and reliability over time. Our work enables creation of a hydrophobic condenser surface with the directional self-cleaning property that can be used for collection of biological (chemical, environmental) aerosol samples or for condensation enhancement.