[2] Passive middle ear implants (PMEIs) are sometimes known as ossicular replacement prostheses, TORPs or PORPs.
PMEIs are the usual first-line surgical treatment for conductive hearing loss, due to their lack of external components and cost-effectiveness.
The implant sends the signals to the Floating Mass Transducer (FMT): a small vibratory part that is surgically fixed either on one of the three ossicles or against the round window of the cochlea.
In these cases, the FMT can be coupled to various parts of the middle ear, depending on the patient's pathology: AMEIs have been shown by several studies to be equal or superior to both hearing aids and bone conduction implants.
[4] These findings were supported by Iwasaki et al, who found that both speech intelligibility and quality of life improved after implantation with an AMEI, applied to the round window.
Mojallal et al found that patients whose mixed hearing loss was treated with an AMEI experienced both better word recognition and speech understanding in noise than those who received a bone conduction implant, providing that their bone conduction pure-tone average (0.5 to 4 kHz) was poorer than 35 dB HL.
[7] PMEIs are made from different materials including titanium, teflon, hydroxylapatite, platinum, and nitinol, all of which are suitable for use within the human body.
[7] The tympanoplasty implant is indicated in cases of congenital or acquired defects of the ossicular chain, due to e.g.: It can also be used to treat patients with inadequate conductive hearing from previous middle ear surgery.