[Method of ossicular chain valuation. Experimental measurement and clinical application].

AIM OF STUDY

Evaluation of usefulness new non-contact method--Laser Doppler vibrometry (LDV) in measurements of movability of ossicular chain during second look operation was aim of the study. We would like answer to questions: 1. Is LDV helpful in intraoperative conditions? 2. Which measurements points have the largest practical value? 3. Which measured parameters could be used to determination of effectiveness ossicular chain reconstruction?

METHODS AND MATERIALS

In experiment there were taken 3 fresh temporal bones kept in 0,9% NaCl. In first stage were executed: antromastoidectomy with wide tympanotomy. The ossicular chain movability investigation was conducted on: back branch of stapes, front branch of stapes, round window, umbo of eardrum. Laser Doppler Vibrometer was used to measurement ossicular chain's movability. ER-2 loudspeakers were generated wave: 1000 Hz, 2000 Hz, 4000Hz. In second stage were executed: Malleus-Stapes Assembly (MSA) ossicular chain's reconstruction and repeated investigation in measured points.

RESULTS

The most convenient points to measurement were respectively: back branch of stapes, front branch of stapes, umbo of eardrum. In two cases round window was placed in deep niche and was partly covered by facial nerve. MSA performance didn't influence accessibility of measuring points. Theresholds of measured point's movability was useful to evaluation of reconstruction.

CONCLUSIONS

Back branch of stapes, front branch of stapes and umbo of eardrum are useful to intraoperatve measurements ossicular chain movability. Delimitation thresholds of ossicular chain movability can help in reconstruction's evaluation. After next experiments LDV can be use in practice-intraoperative.