[First experiences with a new nickel-titanium piston with a shape memory feature].

BACKGROUND

The aim of this study was to describe a new stapes prosthesis with memory characteristics for wire crimping (SMart-Piston).

PATIENTS AND

METHODS

This technique was used in 15 patients (mean age 43.4 years; range 28-71) undergoing routine stapes surgery. SMart-Piston prostheses with a shaft diameter of 0.5 mm and length ranging from 4.25-4.5 mm were used. Heat induced wire crimping was performed by CO2 laser in five patients, and by bipolar diathermy forceps in ten patients. In 15 patients, postoperative audiological testing was performed at an average 21.9 days and in another 10 again after 435 days following surgery.

RESULTS

The median observed air-bone-gap (ABG) postoperatively was 8.7 dB+/-7.7 dB. A total of 73% of all patients had an ABG of 10 dB or less, and all patients had less than 20 dB. In the ten patients controlled after 435 days, the ABG was 4.4 dB+/-2.4 dB. It was lower than 10 dB in all individuals.

DISCUSSION: A critical point in every stapes surgery, the prosthesis fixation to the incus, is greatly facilitated by this novel technique. Long-term results in a larger group of patients are pending.