my lecture nemec temporal bone course
TRANSCRIPT
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
DEVELOPMENT OF THE MASTOID AIR CELLS
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
DEVELOPMENT OF THE MASTOID AIR CELLS
• 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
BASIC PROCEDURES IN EAR SURGERY
• 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)
BASIC PROCEDURES IN EAR SURGERY
• 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
BASIC PROCEDURES IN EAR SURGERY
• 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
BASIC PROCEDURES IN EAR SURGERY
• 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
BASIC PROCEDURES IN EAR SURGERY
• 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.