Application of ti-ni shape memory alloys to the otorhinolaryngological field

Here we have reported on the application of Ti-Ni shape memory alloy as a snare of tonsillectomy and nasal polypotomy, together with a spring of a nasal speculum. 1) When the Ti-Ni alloy wire was pretreated by a shape memory thermal process, the original shape of the wire could be easily recovered on the use by a treatment with heated air, hot water or electric current using electrocoagulation forceps; The snare could be used repeatedly. Since any heating only added to the recovery of the original shape, sterilization procedure did not cause any trouble. 2) It was possible to remove the nasal polyp by strangulation. For tonsillectomy, we advise to deepen by about 1mm the groove for fixing a Krause type snare. We should, however, be careful in elevating the tonsil. 3) We applied a Ti-Ni alloy having a super-elasticity as openning spring of the nasal speculum. This material, which is sometimes called “rubber like metal” because of this super-elasticity, give rise to a constant force for opening the nasal speculum and a negligible dependence of the force on the nostril dimension. It was easily changeable the direction of the nasal speculum to some extent. Moreover, the instrument was light, easy to handle, and self-retained.