Chapter 39 - Tympanomastoidectomy, OCR

Question 1

Key landmarks for mastoidectomy

Answer 1

S: tegmen (separate MCF from ear)
P: sigmoid sinus
D/M: lateral SCC, incus (in aditus ad antrum)
A: posterior canal wall
CN VII

Question 2

When CWD mastoidectomy is indicated

Answer 2

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

Question 3

When to perform second look

Answer 3

After CWU mastoidectomy

6-12 mo

Question 4

Borders of facial recess

Answer 4

A: chorda
P: CN VII
S: incus buttress

Facial recess is pathway to middle ear
Air cells same level as short process incus

Question 5

When to use TORP vs PORP

Answer 5

TORP when stapes suprastructure not present

PORP when stapes suprastructure present

Question 6

Borders of complete mastoidectomy

Answer 6

S: tegmen
P: sigmoid sinus
A: posterior canal wall

Question 7

Modified radical mastoidectomy vs Radical

Answer 7

CWD
Epitympanum, mastoid antrum, EAC become common cavity

Radical: TM and ossicles (except stapes) removed , no reconstruction

Question 8

Indications for mastoidectomy

Answer 8

Cholesteatoma, mastoiditis, subperiosteal abscess

CI, VII decompress, tbone tumor excision

Question 9

Aditus ad antrum

Answer 9

connection between mastoid and middle ear

Has lateral SCC, incus

Question 10

DIsadvantages of CWD

Answer 10

mastoid bowl cerumen requires debridement
meatoplasty visible
Hearing poor with acoustic changes
Water restrictions

Question 11

Disadvantages of CWU

Answer 11

recurrent/residual cholesteatoma
limited exposure of attic, antrum, facial recess
second look

Question 12

How to treat lateral SCC fistula

Answer 12

leave some cholesteatoma matrix over fistula, resect the rest
Rarely, resect entire cholesteatoma, patch fistula, preserve endolymph

Question 13

Complications of mastoidectomy

Answer 13

CN VII, SNHL, CSF leak, dural venous sinus injury

Minor: change in taste, vertigo, TM perf

Question 14

Bondy atticotomy

Answer 14

endaural incision, then atticoantrostoy
take down bone overlying attic to inferior level of dz
preserve pars tensa, ossicles

Question 15

When to use inside out mastoidectomy

Answer 15

low lying tegmen
anterior sigmoid sinus

tympanomeatal flap –> start drilling with atticostomy/posterior wall rather than starting at mastoid cortex

Question 16

Indications for OCR

Answer 16

CHL due to ossicular abnormality (due to cholesteatoma, surgery, ear dz, trauma)
Do OCR when ear free of dz

Question 17

Contraindication for OCR

Answer 17

AOM absolute

relative- persistent middle ear disease (cholesteatoma), dehiscent facial nerve overlying oval window, only hearing ear

Question 18

TORP vs PORP

Answer 18

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

Question 19

When to use bone cement in OCR

Answer 19

reconstructing long process of incus

stabilize prostheses

Question 20

Incus interposition graft

Answer 20

Issue with incus joint(s) but NL malleus/stapes

Remove incus, carve (groove for malleus, cup for stapes capitulum), replace

Question 21

How to classify results of OCR

Answer 21

ABG
Excellent: <10 dB
Good: 10-20
Fair: 21-30

Question 22

Are hearing outcomes better with TORP or PORP?

Answer 22

PORP

Question 23

Complications of OCR

Answer 23

perilymphatic fistula –> SNHL, vertigo, extrusion/displace prostheses, TM perf, CN VII, taste

Question 24

3 areas you can’t see well with transcanal/postauricular unless you have endoscopes

Answer 24

facial recess, hypotympanum, attic