Transcript Overlay Grafting

Overlay Grafting
Prof. Mahmoud El Samaa
Prof. of ORL, head of ENT Dep
Ain Shams University
Edited by
Prof. Mohamed El Begermy
www.entainshams.com
Temporal Bone Laboratory
Ain Shams University
Overlay Grafting of Tympanic
membrane
Skin Incision
This part
exposes fascia
This part exposes mastoid
Hockey stick skin incision
Temporal Bone Laboratory
Ain Shams University
Overlay Grafting of Tympanic
membrane
Exposure& harvesting temporalis
fascia
Temporal Bone Laboratory
Ain Shams University
Overlay Grafting of Tympanic
membrane
Canal Skin
incision
Incision at
Tympanosquamous
suture
Incision 2mm from
annulus
Vascular strip
Temporal Bone Laboratory
Ain Shams University
Incisions are made
along the two suture
lines the
tympanosquamous and
tympanomastoid suture.
This area demarcates
the vascular strip which
is the area of the canal
skin that covers the
superior and posterosuperior portions of the
canal.
Incision at
Tympanomastoid
suture
Overlay Grafting of Tympanic
membrane
Elevation of vascular strip
Vascular
strip
The skin of the
vascular strip is
elevated laterally
keeping it pedicled
superiorly
Dierection
of elevation
Temporal Bone Laboratory
Ain Shams University
Overlay Grafting of Tympanic
membrane
Elevation of the vascular strip
Skin incision
Temporal Bone Laboratory
Ain Shams University
Dissection
elevation
Overlay Grafting of Tympanic
membrane
A circumferential incision
is made in the outer third
of the bony canal with a
beaver knife, connecting
the two incisions.
Temporal Bone Laboratory
Ain Shams University
Overlay Grafting of Tympanic
membrane
The canal skin is elevated from the bone posteriorly as far as the annular ligament.
The dissection continues anteriorly and inferiorly parallel to the annular ligament to
avoid elevating it the tympanic membrane remnant.
Temporal Bone Laboratory
Ain Shams University
Overlay Grafting of Tympanic
membrane
Elevation of anterior
inferior & suprior skin
3- Elevation is done in such a
way that the remnant is deepithelialized in continuity with
the canal skin. Red arrow.
The skin is removed from the
ear and kept moist in saline
Temporal Bone Laboratory
Ain Shams University
1- The dissection
proceeds superficial to
the fibrous layer along
the inferior and anterior
walls,
2- Dissection then
proceeds along the
superior canal wall and
carried medially until the
skin has been freed of all
its attachments.
Overlay Grafting of Tympanic
membrane
Enlargement of the ear canal
This is done by removal of
the anterior canal bulge with
a curette or a drill.
Advantages :
Removal of the anterior bulge
enlarges the field of surgery.
The anterior sulcus is exposed
to allow de-epithelialization
and satisfactory graft
placement.
The acute angle in this area is
opened, preventing postoperative blunting.
There is no hidden area from
post-operative observation.
Temporal Bone Laboratory
Ain Shams University
Overlay Grafting of Tympanic
membrane
Placement of the fascia:
Grafting begins after all
squamous epithelium is
removed.
The fascia is put under the
manubrium and a slit is cut
to allow its placement.
The fascia is placed over the
perforation (on the outer
surface of the tympanic
membrane remnant) and is
adjusted anteriorly and
inferiorly.
Be sure that it does not
extend onto the bone wall
anteriorly, to avoid blunting
problem.
Temporal Bone Laboratory
Ain Shams University
Replacement of
canal skin
The canal skin is
replaced to cover
the bone from
which it was
removed. It is
positioned slightly
more medially,
however, allowing
it to overlap the
fascia by a few
millimeters.
Overlay Grafting of Tympanic
membrane
Return the vascular strip
in its place
Temporal Bone Laboratory
Ain Shams University
Overlay Grafting of Tympanic
membrane
The canal is packed securely with pledgets of gelfoam
Temporal Bone Laboratory
Ain Shams University
Overlay Grafting of Tympanic
membrane
Advantages of Onlay grafts
1- High graft take
rate.
2- Better exposure.
Temporal Bone Laboratory
Ain Shams University
Overlay Grafting of Tympanic
membrane
Disadvantages
More difficult in mastering the
technique.
Higher incidence of healing problems
interfering with the functional result
including:
i. Lateralization of the graft
ii.Blunting in the anterior sulcus
iii.Excessive membrane thickness
iv.Epithelial pearls
Temporal Bone Laboratory
Ain Shams University
Overlay Grafting of Tympanic
membrane
Temporal Bone Laboratory
Ain Shams University
Overlay Grafting of Tympanic
membrane
Lateralization of onlay graft
Lateralized onlay graft, Blunting
correct position,
Temporal Bone Laboratory
Ain Shams University
Definition:
lateral displacement of the graft
away from maleus handle. This
results if the graft is not firmly
seated in place or lateral traction
by the healed fibrous tissue
How to avoid:
Absolute hemostasis.
Discontinuation of the nitrous
oxide 30 minutes before
grafting.
The placement of the graft
under the maleus handle.
Avoid blowing of the nose
and Valsalva’s postoperatively.
Overlay Grafting of Tympanic
membrane
II- Blunting of anterior meatal angle
Definition: formation of fibrous
tissue at the anterior meatal angle
bdeep to the anterior part of the
graft. This decreases the vibrating
area of TM graft
Blunting of anterior
meatal angle
Temporal Bone Laboratory
Ain Shams University
This occurs if the graft is not
accurately placed so that it does
not extend to the anterior wall.
How to avoid:
1- Removal of the anterior hump to
open the anterior angle.
2- Avoid placement of the fascia
onto the anterior canal bone.
3- Be sure that the replaced canal
skin averlaps the graft a few
millimeters anterosuperiorly.
Overlay Grafting of Tympanic
membrane
Other complications
III- Excessive membrane thickness: This may
be due to excessive thicknes of the fascia graft,
delayed healing of the canal, post-operative
infection and ET insufficiency.
IV- Epithelial pearls: This usually results from
inadequate de-epithelialization of the remnant or
adjacent bone. It develops slowly between the
remnant and fascia. It is usually localized and
inferior and it is marsupilized as soon as it is
recognized.
Temporal Bone Laboratory
Ain Shams University
Overlay Grafting of Tympanic
membrane
Temporal Bone Laboratory
Ain Shams University
Overlay Grafting of Tympanic
membrane