HSC Section 8_April 2017

DOES COUPLING & POSITIONING IN VIBROPLASTY MATTER?

round window direct placement group’s coupling effi- ciency was compared to that of the round window fascia group, the difference was significant ( p G 0.05). When the average of the combined RW application groups (both direct contact subjects and fascia interposed subjects) was compared to the stapes vibroplasty, the coupling for the stapes vibroplasty was significantly better ( p G 0.05). There was also a difference, though not significant ( p = 0.08), between the round window direct and the stapes vibroplasty groups with the stapes group demonstrating the trend for

of Rajan et al. (8). No subjects undergoing incus or stapes vibroplasty experienced any postoperative complications.

Coupling Measurements The relation of vibroplasty thresholds and bone con- duction thresholds is shown in Figure 2. Patients with a soft tissue coupler between the FMT and the RW had significantly reduced coupling efficiency as analyzed by a Mann-Whitney U test ( p G 0.05) when compared to all other coupling configurations. When the

FIG. 3. Vibroplasty of the 16 patients across the different frequencies. Patients with stapes and incus coupling as well as those with direct coupling have below average functions reflecting better coupling efficiency. The underlying assumption is that data points below the re- gression line are indicative of ‘‘good’’ coupling.

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