Round window's movability measurements with helping of LDV in evaluation of ossicular chain functioning.
Aim of study: Quantitive evaluation of round window movability in normal conditions and after malleus stapes assembly reconstruction were aims of the study.
Methods and materials: In the experiment there were taken 10 non-frozen temporal bones harvested within 48 hours. Temporal bones specimens were prepared like in closed technique with antromastoidectomy and large posterior tympanotomy. Hearing system before and after MSA reconstruction were evaluated by measurement of round window movement. Measurements were performed at four frequencies: 1000 Hz, 2000 Hz, 4000 Hz, 8000 Hz.
Results: In the normal ossicular chain the biggest movability were stated at frequency of 1 kHz. After reconstruction at all frequencies measurements were significantly worse. In reconstructed ears the highest movabilities were stated at frequencies 2000 Hz and 4000 Hz.
Conclusions: Round window movability could be measured by Laser Doppler Vibrometry in posterior tympanotomy approach. Before reconstruction the biggest movability were evaluated at 1000 Hz and after MSA at 2000 Hz