Myringoplasty

Closure of perforation of pars tensa of the tympanic membrane
is called myringoplasty. It has the advantage of:
(i) restoring the hearing loss and in some cases the
tinnitus.
(ii) checking re-infection from external auditory canal
and eustachian tube (nasopharyngeal infection
ascends easily via eustachian tube in the presence
of perforation than otherwise).
(iii) checking aeroallergens reaching the exposed middle
ear mucosa, leading to persistent ear discharge.
Myringoplasty can be combined with ossicular reconstruction
when it is called tympanoplasty.
Physiologic principles for middle ear reconstruction
are discussed on page 32.
Contra indications
(i) Active discharge from the middle ear.
(ii) Nasal allergy. It should be brought under control
before surgery.
(iii) Otitis extema.
(iv) Ingrowth of squamous epithelium into the middle
ear. In such cases, excision of squamous epithelium
from the middle ear or a tympanomastoidectomy
may be required.
(v) When the other ear is dead or not suitable for
hearing aid rehabilitation.
(vi) Children below 3 years.
Anaesthesia
Local or general, the former is preferred.
Position
Supine with face turned to one side; the ear to be operated
is up.
Graft materials used are:
(i) Temporalis fascia (most common),
(ii) Perichondrium from the tragus,
(iii) Tragal cartilage,
(iv) Vein.
Incision for exposure of tympanic membrane depends
on the size of the ear canal; it may be endomeatal, endaural
or posta ural.
Technique
Underlay Technique
1. Harvesting the graft of temporal is fascia or perichondrium
from the tragus.
2. Preparing the T.M. for grafting. An incision is
made along the edge of perforation and the ring of
epithelium removed. Remove also a strip of mucosal
layer from the inner side of perforation.
3. Inspecting the middle ear. A stapes-type incision
is made and the tympanomeatal flap raised to see the
integrity and mobility of the ossicular chain and to
ensure that no squamous epithelium has grown into the
middle ear.
4. Placing the graft. Middle ear is packed with
gelfoam soaked with an antibiotic. A proper sized graft is
placed so that its edges extend under the margins of perforation
all round and a small part also extends over the
posterior canal wall. Tympanomeatal flap is replaced. An
underlay technique has the advantage that the squamous
epithelium is not buried in the middle ear.
Overlay Technique
1. Temporal fascia or perichondrial graft is harvested as
above.
2. Incision is made in the meatus as shown (Fig. 79.1)
and meatal skin raised along with all epithelium from the
outer surface of tympanic membrane remnant.
3. Graft placed on the outer surface of TM. A slit is
made in the graft to tuck it under the handle of malleus.
4. Meatal skin removed earlier is now replaced, covering
the periphery of the graft. Ear canal packed with gelfoam
and then with a small antibiotic pack.
A modification of the overlay technique is to place
the anterior edge of fascia graft under the annulus after
removing the epithelium. This prevents blunting of anterior
canal which is seen as a complication of overlay
technique .
5. Closure of endaural or postaural incision.
6. Mastoid dressing.
Post-operative Care
l. Stitches are removed after 5-6 days.
2. Ear pack is removed after 5-6 days without disturbing
the gelfoam.
3. Patient is seen at 3 and 6 weeks after operation.
4. Complete epithelialisation of graft takes 6-8 weeks.
Complications
Underlay Technique
l. Middle ear becomes narrow.
2. Graft may get adherent to the promontory.
3. Anteriorly, graft may lose contact from the remnant of
tympanic membrane leading to anterior perforation.
Overlay Technique
l. Blunting of the anterior sulcus.
2.Epithelial pearls. They are epidermal cysts, when
squamous epithelium is buried under the graft.
3.Lateralisation of graft. Graft loses contact from the
malleus handle resulting in conductive loss. It is prevented
by tucking the graft under the handle.
Other Procedures for Closure of Tympanic
Membrane Perforation
1. Splintage. It is used in fresh traumatic perforations.
The torn edges of the petforation are carefully everted
lmder the microscope and splinted with absorbable gelfoam
placed in the middle ear through the tear. Smaller tears can
be splinted on the outer surface of the tympanic membrane
with a piece of cigarette paper, gelfilm or silicon sheet.
2. Cautery-patching. This is useful in small, longstanding
central perforations where the margins, have
become epithelialised and chronic. In this procedure,
margins, of the perforation are cauterised with 50%
trichloracetic acid to remove the epithelialised edge (or
freshened with a fine pick used for myringoplasty) and
then supported with a cigarette paper moistened with
1 % phenol in glycerine. This procedure can be repeated
at two weeks interval. Instead of cigarette paper, other
material such as steristrip, gelfilm or silicone sheets have
also been used .
3. Fat-graft myringoplasty. It is also used to close
small perforations. After local anaesthesia, edges of perforation
are freshened with 1 mm stapes hook. The inside
of perforation is also scrapped. A small piece of fat harvested
from the ear lobule is plugged into the perforation
like an hour-glass. Over a time, the fat graft adheres and
closes the perforation.