Chapter 39 - Tympanomastoidectomy, OCR Flashcards
Key landmarks for mastoidectomy
S: tegmen (separate MCF from ear) P: sigmoid sinus D/M: lateral SCC, incus (in aditus ad antrum) A: posterior canal wall CN VII
When CWD mastoidectomy is indicated
SCC fistula with adherent cholesteatoma, posterior wall damage 2/2 cholesteatoma, sclerotic mastoid prevents visualization, attic or mastoid cholesteatoma in pt unable to f/u or undergo multiple surgeries, cholesteatoma involving sinus tympani not accessible transcanal or through facial recess, unresectable cholesteatoma on dura or posterior cranial fossa
When to perform second look
After CWU mastoidectomy
6-12 mo
Borders of facial recess
A: chorda
P: CN VII
S: incus buttress
Facial recess is pathway to middle ear
Air cells same level as short process incus
When to use TORP vs PORP
TORP when stapes suprastructure not present
PORP when stapes suprastructure present
Borders of complete mastoidectomy
S: tegmen
P: sigmoid sinus
A: posterior canal wall
Modified radical mastoidectomy vs Radical
CWD
Epitympanum, mastoid antrum, EAC become common cavity
Radical: TM and ossicles (except stapes) removed , no reconstruction
Indications for mastoidectomy
Cholesteatoma, mastoiditis, subperiosteal abscess
CI, VII decompress, tbone tumor excision
Aditus ad antrum
connection between mastoid and middle ear
Has lateral SCC, incus
DIsadvantages of CWD
mastoid bowl cerumen requires debridement
meatoplasty visible
Hearing poor with acoustic changes
Water restrictions
Disadvantages of CWU
recurrent/residual cholesteatoma
limited exposure of attic, antrum, facial recess
second look
How to treat lateral SCC fistula
leave some cholesteatoma matrix over fistula, resect the rest
Rarely, resect entire cholesteatoma, patch fistula, preserve endolymph
Complications of mastoidectomy
CN VII, SNHL, CSF leak, dural venous sinus injury
Minor: change in taste, vertigo, TM perf
Bondy atticotomy
endaural incision, then atticoantrostoy
take down bone overlying attic to inferior level of dz
preserve pars tensa, ossicles
When to use inside out mastoidectomy
low lying tegmen
anterior sigmoid sinus
tympanomeatal flap –> start drilling with atticostomy/posterior wall rather than starting at mastoid cortex
Indications for OCR
CHL due to ossicular abnormality (due to cholesteatoma, surgery, ear dz, trauma)
Do OCR when ear free of dz
Contraindication for OCR
AOM absolute
relative- persistent middle ear disease (cholesteatoma), dehiscent facial nerve overlying oval window, only hearing ear
TORP vs PORP
PORP sits on stapes head
TORP sits on stapes footplate
cartilage graft on head of prosthesis to prevent extrusion through TM
Made of titanium and hydroxyapetite-polyethylene
When to use bone cement in OCR
reconstructing long process of incus
stabilize prostheses
Incus interposition graft
Issue with incus joint(s) but NL malleus/stapes
Remove incus, carve (groove for malleus, cup for stapes capitulum), replace
How to classify results of OCR
ABG
Excellent: <10 dB
Good: 10-20
Fair: 21-30
Are hearing outcomes better with TORP or PORP?
PORP
Complications of OCR
perilymphatic fistula –> SNHL, vertigo, extrusion/displace prostheses, TM perf, CN VII, taste
3 areas you can’t see well with transcanal/postauricular unless you have endoscopes
facial recess, hypotympanum, attic
