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[Use of NiTi shape memory alloys in the eustachian tube to prevent and treat adhesive middle ear].

OBJECTIVE
To explore and assess the use of NiTi shape memory alloys in the eustachian tube to prevent and treat adhesive middle ear.


METHODS
All preliminary study cases were divided into three groups (A: 56 cases of adhesive otitis media, B: 27 cases of otitis media with effusion, C: 52 cases without ear disease as control). The eustachian orifice in all cases was observed by endoscopy. Autopsy of Eustachian tube was done in two specimens. The NiTi shape memory alloys were then installed into the Eustachian tube to prevent and treat adhesive middle ear in 4 cases. The installer of NiTi shape memory alloys was designed by ourselves.


RESULTS
The Eustachian orifice can be classified into three types: wide, narrow and fissured. They comprised of 20, 31 and 5 cases in group A, 9, 13 and 5 cases in group B and 45, 7 and 0 cases in group C, respectively. The differences among three groups were statistically significant (A, B vs C, chi 2 = 29.66, 25.44 respectively, P < 0.001), but the difference between A and B was not statistically significant (chi 2 = 1.59, P > 0.05). Two cases with adhesive otitis media gained good ventilation with Valsalva method and the audiometric improvement of 15-30 dB after the NiTi shape memory alloys installation. One of the two cases with otitis media with effusion gained A-B gap closure over 8 months, and the other still improved with ventilative tube removed. In all 4 cases, there was no any side-effect or signs of patulous Eustachian tube.


CONCLUSION
Adhesive otitis media can be prevented and treated by using NiTi shape memory alloys without any side-effect, but more study is necessary.