[The biomechanical prerequisites for the preservation of stapedius muscle tendon during stapedoplasty].

The objective of the present biomechanical and clinical study was to evaluate the consequences of the preservation of stapedius muscle tendon during stapedoplasty. The biomechanical investigations included mathematical simulation with the construction of the model based on the kinematic approach. The comparative clinical study of the results of stapedoplasty carried out between 2001 and 2010 involved 340 patients (77 men and 263 women) at the mean age of 48.18 years. Twenty patients underwent piston stapedoplasty by the method of Shi, 320 ones were treated by stapedoplasty with the preservation of stapedius muscle tendon. The state of speech hearing and the audiometric air-bone gap (ABG) were deduced from the audiograms. The biomechanical study demonstrated a significant increase in the range of the movements of the long crus of the incus, after the removal of the stapedius tendon muscle and the preservation in part of the acoustic reflex in case of tendon preservation. The preservation of the tendon partly dampened excessive sound vibrations. The clinical study revealed the improvement of speech hearing parameters throughout the three-year postoperative follow-up period; it was especially pronounced within the first year after surgery with the preservation of stapedius muscle tendon. The size of ABG at a the frequencies falling in the 0.5-1 kHz and 6-8 kHz ranges after surgery with the preservation of stapedius muscle tendon was smaller than after the removal of the tendon during the three-year follow-up (p<0.005). The difference was especially well-apparent within the first year after stapedoplasty. The difference in this parameter between the interventions with the preservation of stapedius muscle tendon and with its removal was insignificant (p>0.05).