Katie McKee-Cole

June 15, 2016

CME Code: MUNQOX

Microtia Introduction

Classification schemes

Clinical evaluation

Physiologic/Psychological Impact

Reconstruction

Atresia Introduction

Classification schemes

Reconstruction

Conclusion

Incidence of microtia 1-3 in 10,000

58% right sided, 32% left sided, 9% bilateral

63% male, 37% female

Genetics

w/ positive family history

AD 9%, AR 90%, X 1%

Familial non-syndromal high grade microtia

Predominantly AD w/ variable penetrance

Ischemia

In utero obliteration of stapedial a. or hemorrhage into

local tissues

Chromosomal aberrations

Goldenhar, Treacher-Collins, 18q deletion, others

Teratogens

Thalidomide, isotretinoin, vincristine, colchicine,

cadmium

Maternal infections

Unknown

1900 1950 2000

Marx Rogers

Tanzer

Weerda

Nagata

Aguilar

Grade 1

Pinna malformed and

smaller than normal but

with good definition and

minor anomalies

Grade 2

Helix may or may not

be fully developed

Triangular fossa,

scapha, antihelix have

much less definition

Grade 3

Pinna essentially

absent except for

vertical remnant of

unorganized elastic

cartilage superiorly with

relatively well-formed

lobule

Anotia

Total absence of the

pinna

Brent Classical microtia

Larger lobule with amorphous cartilage remnant

Usually w/ EAC absence

Atypical microtia More recognizable

portions of concha, antihelix, tragus and antitragus

Upper portion absent

EAC may or may not be present

Nagata

Lobular remnant type

deformity

Corresponds to classic

type microtia

Conchal remnant type

deformity

Corresponds to atypical

type microtia

small and large type

depending on conchal

development

Degree of associated facial hypoplasia

Auricular dystopia Medial, inferior and

anterior displacement of auricle or microtic vestige due to underlying facial skeleton deficiency

May also have a dystopic EAC

Timing: ideally within a few weeks after birth

H/o exposure to teratogens sought

Examination:

Anomalous ear, normal ear

Other possible associated anomalies

Hearing status

OAE and/or ABR within first 2-3 months

Bone conduction usually but not always normal w/ CAA

CHL usually maximal due to lack of EAC/ossicle fixation

Renal US

Xray: C, T, L spine to r/o malformations

CT T-bone Possibility of reconstruction

Presence of cholesteatoma

Some obtain at 1 yr, others delay until 5-7 years

3D CT scans in those w/ craniofacial microsomia

Follow in office in 6-12 month intervals

Functional Hearing in b/l cases

Difficulty wearing glasses/hearing aids

Psychological Age < 5 yrs: usually little

psychological impact

Age > 5 yrs: begins to notice difference between ears

Goals to emphasize with parents

1st: Maximizing hearing

Speech development usually normal in u/l microtia/atresia

Frequent otologic evaluations to r/o problems in normal ear

Early use of BAHA softband especially for b/l, but also u/l

Hearing may improve with recon, perfect hearing unlikely

2nd: Cosmesis

An auricle can be created that looks much better than the

vestige but it may not be completely normal

Reconstruction requires several stages

Revisions may be necessary

Observation

Molding

Prosthetic replacement of external ear

Reconstruction with prosthetic framework

Autologous framework with local tissue/flap

coverage

Some grade 1

malformations

Instituted very shortly

after birth

Newer osseointegrated

anchoring systems

Surgical placement of a

titanium anchor

Magnet system and

prosthesis attached

Bone conduction HA

can be built in

Expensive

Precludes future recon

First reported in 1960’s

Then abandoned due

to erosion/exposure

Newer medpor

framework has seen

better results

Long-term follow-up

needed

First reported in 1930’s, expanded in 1940’s

Came to forefront with Brent in 1980’s

Further refinements by Nagata recently

3 main elements among all methods

Construction and placement of cartilage framework

Lobule rotation, conchal excavation and tragus

formation

Elevation of the pinna

B/l vs u/l microtia w/ or w/o atresia

Recommended age varies widely

Early

Psychological impact minimized, hearing function improved

at earlier age

Later

Better cosmetic outcome, patient compliance

Microtia repair prior to atresia to preserve blood

supply

Template for positioning

of reconstructed auricle

Template for cartilage

framework

Low hairline

Assessment of costal

cartilage volume

3 levels or complexes of

reconstruction

Proportions and relative

position

Constructed from costal

cartilage fragments from

6th-8th ribs

Opinions on ipsilateral

vs contralateral differ

Alterations with conchal

remnant microtia

Cartilage banked for

projection

Cartilage framework constructed

Vary by technique Nagata, Firmin, Bauer:

rotation of the lobule and tragal construction at 1st

Brent: delay lobule transposition and tragal reconstruction till 2nd

Amorphous cartilage excised, framework can be spliced into usable portions

3-4 months after 1st

Nagata and Firmin:

Elevation of

reconstructed ear

Brent:

Rotation of the lobule,

conchal excavation

Brent:

construction of tragus

elevation of the reconstructed ear

Cryptotia repair is similar to the 4th stage

Post-op scar formation can obliterate part of the sulcus and decrease projection

Ideal procedure yet to

be achieved

Altered vascular

anatomy

Transposition of microtic

vestige

Framework construction

modified due to

hypoplastic base

Infection

Cartilage/soft tissue loss

Chest wall deformity

Pneumothorax

Failure of development

of EAC and middle ear

Generally have normal

cochlear function

Epidemiology

1/10K-20K live births

3-4 u/l : 1 b/l

Right > left

Male > female

Degree depends on

point of interruption of

development

Group 1

Normal or stenotic

canal with hypoplastic

middle ear and mild

malformation of the

ossicles

Group 2

Fistulous tract or

complete atresia of the

canal with a bony

atretic plate and some

degree of malformation

of the middle ear

structures

Group 3

Complete ear canal

atresia with

nonpneumatized

mastoid and middle ear

Atresia commonly

coexists with microtia,

can occur alone

Restoration and stability

of hearing

Maintenance of a

patent, skin-lined EAC

Softband bone

conduction aid

BAHA

Alterations in technique

Additional resources for

hearing loss

Preferential seating,

FM system,

individualized

education program,

speech therapy

Anatomic considerations

Malleus-incus complex

(MIC) large & directly

lateral to the stapes

Low lying tegmen

Facial nerve obstructing

oval window

Facial nerve turns

anterolateral obstructing

attic/middle ear

TMJ lateral to middle ear

Anomaly of the inner ear

Unilateral

Early repair

Late repair

Bilateral

Hearing status

Favorable anatomy

Microtia implant

Schuknecht methods

Transmastoid

Jahrsdoerfer anterior

approach

Standard in atresia

surgery today

Anesthesia concerns

Facial nerve monitoring

Avoid nitrous oxide

Temporalis fascia graft

obtained

Mastoid periosteal

incisions

Identification of

landmarks

Drill atretic bone

Enter middle ear in

epitympanum

Establish status of

ossicles

Fascia grafting

Skin grafting

Meatoplasty

Periodic debridement

May swim after 1 month

Facial nerve injury

Sensorineural hearing loss

Need for revision

Newer alloplasts

Tissue engineering

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Advisor: Dr. O’Reilly