Date post: | 11-Aug-2015 |
Category: |
Documents |
Upload: | surabhi-pagudala |
View: | 16 times |
Download: | 3 times |
BONE ANCHORED HEARING AID (BAHA)
What is a BAHA?
A Bone-Anchored Hearing Aid - is a type of
implantable hearing aid primarily suited to
people who have
conductive hearing loss,
unilateral hearing loss
mixed hearing loss who cannot otherwise
wear 'in the ear' or 'behind the ear' hearing
aids.
It has been in use
from 1977 in Europe
It got approved by
FDA in 1996
Principle
Directly stimulates the
inner ear via bone
conduction bypassing
middle and outer ear
Indications for BAHA
1. When air conduction hearing aid
cannot be used
Canal atresia, congenital or acquired
not amneble to treatment
Chronic ear discharge not amneble to
treatment
Excessive discomfort from air
conduction hearing aid
2. Conductive or mixed hearing
loss Ex: otosclerosis and
tympanosclerosis where surgery
is contraindicated
3. Single-sided hearing loss
Three components of the BAHA system
The sound processor
The abutment
The fixture (or implant)
Titanium screw
4mm long implanted
into skull bone behind
the ear
Permanent, not
adjusted or removed
Becomes firmly
anchored to the bone
by process called
osseointegration
Titanium abutment
is a socket fitted to the
titanium screw
is shaped to hold coupling
of the sound processor
can be unscrewed from
the fixture for maintenance
or replacement by the
specialist audiologist.
Sound processor
Is attached to the
abutment once
osseointegration is
complete
Takes 2 weeks to 6
months after
implantation
Detachable, can be taken
off during hair washing or
swimming
Criteria required for BAHA
There should be at least one working
cochlea
Minimum bone conduction threshold
level required is 45db for effective
function of BAHA
speech discrimination should be more
than 60 percent for BAHA implantation
to be successful.
Implantation procedure
The site for the implant is
identified behind the ear
and is marked.
Usually post-superior to
the EAC.
A split thickness graft is
raised using a
dermatome.
The subcutaneous
tissue is removed
leaving the
periosteum intact.
The site to receive
the implant is
drilled.
The titanium implant
is slowly inserted
under constant
irrigation.
The split skin graft is
returned and
abutment is fitted .
Surgical technique
Single stage : The transcutaneous
abutment is placed at the same setting.
Double stage : Usually done in children
and babies. In the first stage the implant is
placed. After 3 months when
osseointegration is complete the second
stage i.e placing of the abutment is done.
Follow up
First at 2 weeks after the surgery for
inspection of the site. Then at 2
months,when the hearing of the
patient is assessed again.
The patient is asked to maintain the
abutment site clean to prevent
infection and skin reaction.
Complications
Soft tissue overgrowth
Skin infection
Abutment and fixture dislodgement
Trauma
Persistent pain at abutment site
Failure to osseointegrate
Granulation tissue at abutment site
Persistent bleeding at the abutment site
Thank you