Middle ear implants are advanced hearing aids designed for patients with mild to severe hearing loss, offering advantages over conventional devices such as improved sound quality and reduced feedback. These implants can be partially or fully implanted, with variations like electromagnetic and piezoelectric systems providing unique benefits and drawbacks. Ideal candidates for these devices have specific audiological and medical criteria while contraindications include history of middle ear diseases or significant dysfunctions.

1. MIDDLE EAR IMPLANT , INDICATION
AND CONTRAINDICATION

2. INTRODUCTION
• Middle ear implants represent a type of hearing aid
that has a potentially widespread application to
patients with mild to severe hearing loss
• The main purpose to develop these devices has come
from patient dissatisfaction with conventional
amplification aids relating to performance
• sound quality , occlusion effects band acoustic
feedback , discomfort
• social stigma and cosmetic implications
• wax blocking bthe receiver
• recurrent otitis externa

3. • Implantable hearing aid differ from conventional
hearing aids in that they are partially or totally
implanted and directly couple acoustic energy to the
ossicular chain or cochlea
• in exchange for the added surgical risk and cost
associacted with implantation , they offer several
potential advantages over conventional hearing aids
including
• Increased gain and dynamic range
• reduced feedback , reduced maintenance
• Improved appearance
• freedom from ear canal occlusion.

4. • Wilska is credicted with being the first to use
electromagnetic induction to stimulate the
middle ear

5. BASIC PRINCIPLE
ELECTROMAGNETIC;
ELECTROMAGNETIC transducers generate a
magnetic field using a wire coil carrying a current
that encodes the microphone output.
This magnetic field induces motion of a nearby
magnet , which can either be separate from the
coil and attached alone to the ossicles or
integrated with coil to become a vibrating
compound mass affixed to the ossicles

6. • PIEZOELECTRIC
• this devices move ossicles using a piezoelectric
crystal that bends or lengthens in time with
changes in a signal voltage applied across it .
• Piezoelectric ossicular actuators yield greater
power and less distortion than electromagnetic
devices, but requires precise placement to ensure
proper compressive force between the actuator
and the ossicles it contacts.

7. TOTAL VERSUS PARTIALLY
IMPLANTABLE HEARING DEVICES
• Partially implantable devices consist of an external
microphone and speech processor connected to a
transmitter with an external coil that transmit electric
energy transcutaneously to the internal device
• Battery powered system is contained within the
external device ( decreases the size of the implanted
component ).
• The internal device consists of an internal receiving coil
, which provides electric energy to the mechanical
driver connected to the ossicular chain

8. • Fully implantable system house all of the
above mentioned component within the
implanted portion of the device , including the
battery pack
• Because of the finite life if the rechargeable
batteries : requires reoperation at approx. 5
year interval to exchange the battery
• More complex and bulky

9. VIBRANT SOUNDBRIDGE
• Partially implantable active middle ear device that uses
electromagnetic energy to mechanically drive the
ossicular chain
• Two components :
• External component – audio processor secured
magnetically to the scalp
• Internal component – implanted vibrating ossicular
prosthesis ( VORP) attached to a floating mass
transducer
• The FMT is coupled to the ossicular chain with an
attachment clip to serve as an electromagnet
transducer

10. • Sound detected by audio processor
microphone is processed and relayed across
the skin to the internal receiver of the VORP .
• Electrical signals are then relayed from the
VORP to the FMT , which in turn generates
vibration from the oscillating magnet within
an electromagnetic filed drive the ossicular
chain

12. MIDDLE EAR TRANSDUCER AND
CARINA
• Is an electromagnetic middle ear hearing aid
• Originally , semi-implantable MET has been
replaced by fully implantable CARINA

13. • Via a postauricular incision, a well is drilled to
house the implant body and then a limited
mastoidectomy is performed to expose the
incus body and malleus head
• A laser is used to make a small pit in a
posterosuperior incus body , and then

17. ESTEEM – HEARING IMPLANT ( ENVOY
MEDICAL CORP.)
• Is a fully implantable piezoelectric device
• One especially notable design feature of the
ESTEEM is its use of the tympanic membrane
and malleus as a microphone diaphragm

19. • DRAWBACK:
• Implantation of the esteem requires partial
removal of the incus to prevent feedback from
the actuator to the sensor. This results in a
maximal CHL in the event of device failure or
removal , unless an ossiculoplasty is performed
• the internal battery must be replaced
approximately every 5 years, and this requires
repeated surgeries

21. DIRECT ACOUSTIC COCHLEAR
IMPLANT
• It consist of an implantable electromagnetic
transducer and external audio processor
• Indicated in profound hearing loss

23. SEMI IMPLANTABLE MIDDLE EAR
ELECTROMAGNETIC HEARING DEVICE (
SIMEHD)
• A magnet is cemented to the body of the
incus
• There is an implantable electromagnetic coil
that is supported by a titanium frame which
is fixed to the temporal bone .

24. PIEZOELECTRIC ROUND WINDOW
IMPLANT WITH INFRARED OPTICAL
SIGNAL
• Combinationof an infra- red technology with
piezoelectrics system
• A microtransducer is placed on the round
window , this can receive power and signal
transmission through an infrared optical
transmitter located in an external unit
• This system is implanted endaurally without
mastoidectomy .

25. INDICATION
• Patient selection – ideal candidate
• High frequency sensorineural or mixed
hearing loss , in which amplification with
conventional hearing aid has failed
• Absent of skin infection condition that will
prevent attachment of the external
component of the implant
• Patient should be medically fit for surgery and
anesthesia

26. • Audiological considerations
• Current devices are mostly suitable for mild to
severe SNHL
• hearing loss should be stable or gradually
progressive
• The ear which is severly affected is first
selected for the implant.

27. • Otological considerations
• Absence of retrocochlear or central
involvement in hearing loss
• no middle ear inflammation
• the external auditory canal ( EAC) must be
assessed if suitable for an external processor
or is fit to hold the processor .

28. CONTRAINDICATION
• History of significant eustachian tube dysfunction
, active middle ear disease
• Prior ossiculoplasty or stapes surgery
• Meniere disease or inner ear disease with
fluctuating hearing loss
• Retrocochlear pathology
• Disabled tinnitus
• Anticipated need for MRI in the future
• Bleeding disorder