Cochlear implant clinical technique
I. Cochlear implantation
Indications
(A) Patients with prelingual deafness.
1. Severe or very severe sensorineural deafness in both ears.
2.The best age should be 12 months-5 years old.
3.No significant improvement in hearing ability after hearing aid fitting.
4. The family has correct understanding and appropriate expectation of cochlear implant.
(B) Patients with postlingual deafness.
1.Severe or very severe sensorineural deafness in both ears.
2.Patients of all ages with post-speech deafness.
3.No significant improvement in speech recognition ability after hearing aid fitting.
4.Patients with correct understanding and appropriate expectation of cochlear implant.
Contraindications
(a) Absolute contraindications.
1. Severe deformities of the inner ear, such as Mic hel deformity or cochlear agenesis.
2.Auditory nerve deficiency.
3.Severe mental illness.
4.Purulent inflammation of the middle ear mastoid has not been controlled.
(II) Relative contraindications.
1, poor general condition of the body.
2. Uncontrollable epilepsy.
【Operating procedures and methods
1.Posterior auricular incision, separation of the flap, incision of the musculocutaneous membrane, exposure of the mastoid process and the posterior wall of the bony external auditory canal.
2, opening the mastoid cavity.
3. The skull surface is ground to create a bone bed for the implant.
4. Open the facial saphenous fossa and perform a cochlear opening.
5.Place the implant in the bone bed, implant the electrode in the tympanic step, and place the reference electrode under the temporal periosteum.
6.Suture the musculocutaneous membrane, subcutaneous and skin in order.
Caution】
1. The surgeon should have more mature ear microsurgery skills and be trained in cochlear implant surgery.
2. Special diseases such as middle ear, inner ear malformation and cochlear ossification should be handled with caution.
Cochlear implant audiological evaluation and commissioning
History taking]
History taking focuses on the cause and course of deafness, including the time of onset and development of the disease.
Audiological examination
1. Subjective hearing threshold determination: pure tone audiometry can be used. In children, behavioral observation, visual reinforcement and play audiometry can be used.
2.Acoustic conductance resistance: including tympanic chamber pressure curve and stapedius muscle reflex.
3, auditory brainstem evoked potentials, 40 Hz correlation potentials (or multi-frequency steady-state evoked potentials).
4, otoacoustic emissions.
5.Speech audiometry.
[Power on and commissioning
1.Turn on the external device 2-4 weeks after surgery.
2.Test the electrode impedance to understand the working condition of the implant.
3, test and set the electrical stimulation threshold and maximum comfort value of each channel.
4.Listening in real time and making appropriate adjustments according to the subject’s response.
5.Save the commissioning results.
6.Re-commissioning with appropriate time interval.
Notes
1. The commissioning professionals should have knowledge of audiology and cochlear implant technology and undergo corresponding professional training.
2.Auditory language rehabilitation training should be conducted after the machine is turned on.