Tympanoplasty

Tympanoplasty
It is an operation to (I) emdicme disease in the middle car
and ( ii) to rec.on stnict heming mechanism. It may be combmcd
wirh mastOldectomy if disease proce~s so nen1~li n s .
TYr€'". of minnie ear reconstructi.on dcpcnJs on r.he d(lm(lge
present in the ea r. The procedure m(lY be limited only to
repair of tympanic memhrane (myringoplast),), or to reconstruc
tion of oss icular chain (ossicuioplaslY), or both (l)'m-
1}{1T1lJl)U1.~t),). Reconsffilcrive surgery of the car has heen
gready facihcared by development of opcrating microscope,
microsurgical instruments and hi(Kompatible implant
materials.
Front the ph)'1'iiology uf hearing mech anism, the follow~
ing principles can be ded uced Lo reslOre hearing surgicillly:(i) An intact tympanic memhrane, to provide large
hydraulic ralio between the rympanic membrane
and stapes f(.:x) tplate.
(ii) Ossicular chain , to conduct sound from tympa nic
membrane ro (he oval window.
( iii) Two funcCluning windows, one 011 the scala veslibuli
([0 receJve sound vibrations) ~nd lhe other on the
scala rympani (to act as <.I re lief window). If it is only
one Window, as in smpes fixation or closurc of round
Window, (here will he no movement uf cochlem
fluids re::.ultin~ in conductivt: he;)[lng loss.
(Lv) Acou.~ tic separation of twO wirnlool.l's, so that sound
does not" reach bo th the 'windows simultaneo usly.
It can be achie ved by providlllg an inrac t tympanic
membrane, prefe re ntia l I,athway to o ne window
(usually the uvcd.) by providing o~::;icu lar c hain and
by the prese nc.e of air in thc miJdle e~r.
(v) Functioning cus wchian tube) to provide J,erthe lUlddle eat.
(v i) A functioning sensorineum/ apparatus, I.e. t he
cochlca and Vllltb ncrv e.
Types of tympanoplasty. Wullstein c l ~ssi fied l ympano~
pl"sry into five types (Fig. S.2).
Type I De fcCl is perforation of tympanic membrane
which i1'i repaired with a graCe It i~ also cill l~rI
myringoplasLY.
Type II Defect is perforation of tymparuc: mc: mhl~lte
with ero~iO n of m~lIel..1s. Uraft is placed un the
incus o r rt:rnn~nt of malleus.
Type III M""eu, and incus are ahscnt. Gra(t is placed
di recd y on the stapes head . it is als() called
mY"ingostapcdiopcX)' flf" columella tympano·
plasty.
T ype IV Only the (ootplutc of stapes is present. Ir is
exposcJ LO the eXTernal ear, and grafr is placed
between the oval and round wiuJows. A narrowmiddle e-al (cClvum minor) is rhus ereattn , to
h~V(' ~n nir pocket around rhe round willdow. A
mlK'( )Sn~ l iTleJ SI);)CC cx(ends from the eustachian
(Ube ro [he round window. Sound wa vc~ in this
case ::let di recrly on the footp late whil ~ the
rou nd window h as been shielded.
Type V Stapes footplate is fix ed hllr round wLndow i::;
iunctioning. In such ('8~CS, another window is
crerlteJ un hOfl2ontal semlC ircular canal and
covered with rt graft. A lso catted fenestration
operation .
Several modificat ions h", ve rJPpeared in the above
classificarion and they mainly perta in [U lhe types of
ossiculnr reconstruction.
My ringoplasty. It is tepair