my Lecture NEMEC Temporal Bone Course

MASTOIDECTOMY

Rosario R. Ricalde, MD, DPBO-HNSQuirino Memorial Medical Center

October 17, 2009Veteran’s Memorial Medical Center

OUTLINE1. Development and anatomy of the temporal bone 2. Development and anatomy of the mastoid air cells3. Normal versus sclerotic mastoid4. Purposes of mastoidectomy5. Definitions 6. Radical versus modified radical vs tympanoplasty with

mastoidectomy7. Canal wall-up versus canal wall-down8. Tips in decision making9. Steps in ear surgery to eradicate disease and/or restore

hearing 10. Surgical principles and techniques in mastoidectomy11. Meatoplasy

TEMPORAL BONE ANATOMY AND DEVELOPMENT

DEVELOPMENT OF THE MASTOID AIR CELLS

Conception

Birth Infantile typeair cells appear

Transitional type

mastoid enlarges with migration of air cells toward

periphery

Mature system

Pneumatization ceases

Diploic type22-24 weeks

Mastoid antrum

develops

0Air cells develop

2 years 5 years


Mastoid Antrum - well developed at birth, size is 1-1.5 cm2

1-6 years old - mastoid cells about 3.5-4 cm2 at 1 year, linear growth till the age of 6 (1-1.2 cm2/year), having a slower increment up to adult size at puberty

Puberty - adult size: 12 cm2


• An aircell is lined by a single flat layer of epithelium separated from bone by subepithelial connective tissue.

• Epithelium + connective tissue = mucus membrane of the air cell• Development of air cells is preceded by the formation of bone

cavities.• After the epithelial mucous membrane has invaginated, it in turn

undergoes atrophy, leaving a thin residual lining membrane attached to the periosteum.

• Recession of the lining membrane and subepithelial bone resorption then further enlarge air cells by the presence of AIR.

• Pneumatization of the temporal bone divided into five (5) regions: middle ear, mastoid, perilabyrinthine, petrous apex, and accessory regions

ADULT ANATOMY OF THE MASTOID AIR CELL SYSTEM

ADULT ANATOMY OF THE MASTOID AIR CELL SYSTEM

NORMAL VS SCLEROTIC MASTOID

PURPOSES OF MASTOIDECTOMY

1. Eradication of disease – removal of diseased mastoid

2. Exploration to ensure that there is no disease – if without CT scan

3. Enlarge the air-conditioning of middle ear-antral space

4. Access or exposure – removal of healthy mastoid to reach a certain structure or area such as in cochlear implantation, lateral skull base (translabyrinthine approach)

DEFINITIONS

• Radical Mastoidectomy• Modified Radical Mastoidectomy (Bondy

Procedure)• Tympanomastoidectomy or Tympanoplasty

with mastoidectomy• Atticotomy• Canal Wall-up Mastoidectomy(CWU)• Canal Wall-down Mastoidectomy (CWD)

DEFINITIONS

Radical Mastoidectomy• Mastoid antrum, tympanum, and external auditory

canal are converted into a common cavity exteriorized through the external meatus

• Removal of the tympanic membrane, ossicular remnants with exception of the stapes and does not involve any reconstructive or grafting procedure

• Surgeon may plug the eustachian tube or lay soft tissue over the middle ear to assist healing

DEFINITIONS

Modified Radical Mastoidectomy (Bondy Procedure) • Epitympanum, mastoid antrum, and external

auditory canal are converted into a common cavity exteriorized through the external meatus

• Tympanic membrane and or its remnants and ossicular remnants are retained to preserve hearing

• Does not involve any reconstructive procedure

DEFINITIONS

Tympanomastoidectomy or Tympanoplasty with mastoidectomy

Performed to eradicate disease on the middle ear and mastoid and to reconstruct the hearing mechanism with or without tympanic membrane grafting

DEFINITIONS

Atticotomy • For disease that is confined to the central

epitympanic area – attic retraction pockets• Drilling of the scutum around the epitympanic

area. The area has to be reconstructed with cartilage or bone pate to prevent recurrence of the retraction pocket

• If the disease extends to the antrum then a mastoidectomy has to be performed

DEFINITIONS

Canal Wall-up (CWU) • Posterior canal wall is PRESERVED • 2 cavities: 1. mastoid

2. middle ear and external auditory canal

Canal Wall-down (CWD) • Posterior canal wall is REMOVED – 1 cavity

RADICAL MASTOIDECTOMY

MODIFIED RADICAL MASTOIDECTOMY

TYMPANOPLASTY WITH MASTOIDECTOMY OR

TYMPANOMASTOIDECTOMY

PURPOSE Eradicate disease Eradicate disease and preserve hearing

Eradicate disease and reconstruct hearing mechanism

REMOVE Mastoid air cells, diseased tissue (granulation), posterior canal wall, tympanic membrane, ossicular remnants

Mastoid air cells, diseased tissue, posterior canal wall

Mastoid air cells, diseased tissue

PRESERVE Stapes Healthy tympanic membrane and ossicular remnants

+/- posterior canal wallHealthy tympanic membrane and ossicular remnants

OTHER POINTS

Eustachian tube pluggingSoft tissue grafting

+/- tympanic membrane grafting

CANAL WALL-UP CANAL WALL-DOWN

HEARING Better hearing +/- Poor hearing

HEALING Faster healing – 1.5 to 2 months

Slower healing – 3 to 8 months

RESIDUAL DISEASE No difference if surgeon is competent

No difference if surgeon is competent

RECURRENT DISEASE 20-40 % recurrence <5 % recurrence

EXPOSURE No problem swimming Water easily goes into ear - vertigo

POST-OP HEARING REHABILITATION

Good fit – no feedback Hard to fit - feedback

FOLLOW-UP Every 1 to 2 years for 10 years

Every 6 to 12 months for the rest of the patient’s life

TIPS IN DECISION MAKINGPRE-OP

– Physical examination – collapsed posterior canal wall, subperiosteal abscess, facial nerve involvement complications of CSOM, extensive disease

– Hearing status – Operate on the worse ear first. But remember, that you have to operate on both ears eventually if indicated.

– Worse ear does not necessarily mean the worse hearing ear. REMEMBER that cholesteatoma can conduct sound. In a person with bilateral cholesteatoma look at the overall clinical picture and the BONE CONDUCTION

– Imaging – NOT ALWAYS NECESSARY. Computed tomography: density in the mastoid, blunting of the scutum, dehiscences

INTRA-OP – Almost always the case– Start with canal wall-up then convert to canal wall-down

BASIC PROCEDURES IN EAR SURGERY

• Inspection of the external auditory canal and inspection of the tympanic membrane / remnant

• Infiltration of lidocanine-epinephine 1:100,000 around 1-2 mm lateral to the non-hair bearing area

• 6 o’clock – 12 o’clock incision 8 mm from the position of the annulus


• Post-auricular incision start superiorly and incise to the level of the temporalis fascia then proceed inferiorly

• Harvest temporalis fascia graft, press and let it dry

• Make an incision to the bone from temporal line to mastoid tip (take note that you can use the periosteal flap to line or obliterate the mastoid cavity)

• Develop the periosteal flap until you see the meatal incision (laterally) , tympanomastoid fissure (inferiorly) and tympanosquamous fissure (superiorly)


• Use self-retaining retractors for better visualization of the middle ear

• Freshen the perforation or the edges of the tympanic membrane remnant

• Develop the tympanomeatal flap

BASIC PROCEDURES IN

EAR SURGERY

• Inspection of the middle ear

• chorda tympani• Inspection of malleus and

incus• Removal of scutum using

stapes curette to visualize the incudostapedial joint


• If disease is confined to the epitympanum then do ATTICOTOMY. Reconstruct defect with cartilage or bone pate. Flap back the tympanomeatal flap.

• If disease is extensive and extends to the antrum then separate the incudostapedial joint before MASTOIDECTOMY

MASTOIDECTOMY• Burr cut perpendicular to temporal line and tangent to external auditor canal• Expose mastoid antrum - in a sclerotic mastoid, sometimes this is the only air cell

left• Saucerization

– Visualize the field better– Instruments can fit

• Use the side of the burrs not the tip• Start antero-superior. This is the deepest part and the location of the antrum.• Locate the sinodural angle where the tegmen and sigmoid sinus intersect. This is

the postero-lateral extent.• Locate the lateral fossa incudis and the lateral semicircular canal to locate

position of the facial nerve• Note the course of the facial nerve• The canal wall should be brought down to the level of the facial nerve in a CANAL

WALL DOWN MASTOIDECTOMY• Removal of cholesteatoma capsule and diseased tissue

Promontory Short process of incus

Fossa Incudis

Lateral semicircular

canal

Mastoid segment of the facial nerve


• Identify ossicles and continuity• Tap each ossicle starting with malleus,

incus, then stapes• Look for rippling or movement of fluid at

the round window nitch to confirm ossicular continuity

BASIC PROCEDURES IN EAR SURGERY - MEATOPLASTY

• Meatoplasty if CANAL WALL-DOWN is performed; no meatoplasty if CANAL WALL-UP IS performed


• Obliteration techniques – temporalis muscle or musculoperiosteal flap

• Ossicular reconstruction• Tympanoplasty• Pack with medicated and dry

gelfoam• Medicated gauze or silk • If CANAL WALL-DOWN close post-

auricular incision in 2 layers• If CANAL WALL-UP suture back

periosteal flap then close post-auricular incision in 2 layers

• Dressing

REFERRENCES• Atlas, Marcus D. A Guide to Temporal Bone Dissection 2nd edition.

Lions Ear and Hearing Institute, Perth, 2004.

• Brackmann, Derald E. (ed). Otologic Surgery 2nd edition. WB Saunders, Philadelphia, 2001.

• Virapongse, Chat, Mohammad Sarwar, Sultan Bhimanoi, et. al. ComputerTomography of Temporal Bone Pneumatization: Normal Pattern and

Morphology. American Journal of Radiology: 145 (173-481), September 1985.

• Nelson, Ralph A. Temporal Bone Dissection Manual. House Ear Institute, Los Angeles, 1991.

• Portmann, Michel and Didier Portmann. Otologic Surgery: Manual of Oto-surgical Techniques. Singular Publishing Group, Inc. San Diego, 1998.

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my Lecture NEMEC Temporal Bone Course