Microtia

Dr sumer yadav

history First- Susruta Samhita-ear lobe – cheek

flap 1597-repair of both upper and lower ear

deformities with retroauricular flaps 1937- Gillies- maternal rib graft -

resorption 1959 -Tanzer- autologous rib-solid block 1966 -Cronin –silastic- extrusion 1974 -Brent -autologous rib-4 1991-Reinisch -MEDPOR® 1994 -Nagata- stacked autologous rib-2

embryology

middle ear and external ear are derived chiefly from the first (mandibular) and second (hyoid) branchial arches.

hearing threshold of 40–60 dB on the affected side-inner ear (ectodermal) normal. BAHA advised in b/l case.

auricle formed from six “hillocks” of tissue that lie along these arches and can be first seen in the 5-week embryo.

Initially, the external ear is located in the region of the lower neck, but as the

mandible develops, the ear ascends the side of the head to the level of the

eyes.

auricle assumes an adult configuration by the 20th week and continues its

postnatal growth until around 9 years of age. It is 85% of its adult size by age

3.

epidemiology

The incidence - ranges from 1 in 500 to 1 in 5000 live births.

Males are affected more often than females. Microtia is a unilateral phenomenon in 90% of cases.

The right side is affected more so than the left. In 80% of patients, the external auditory canal is

atretic or narrow, with associated conductive hearing loss. Approximately 16% of cases have neurosensory hearing loss.

20–40% of patients have associated defects that most frequently involve the face (35%), kidneys (4%), vertebrae, and heart (2.5%).

anatomy

inner elastic cartilage framework covered by perichondrium and a thin skin envelope with scant subcutaneous tissue posteriorly.

Spatial relationships: • The ear width is approximately 55% of its height. • Ear projection measured from the scalp to anterior surface of the

superior pole of the helix is 1.5–2.0 cm. • The superior aspect of the auricle should correspond to the level of the

brow superiorly and the base of the columella inferiorly. • The long axis of the ear is anteriorly rotated 15–20 degrees from the

axis of the nose. The vascular supply to the pinna is via branches of the external carotid

artery: • Posterior auricular artery • Occipital artery • Superficial temporal artery The lesser occipital and greater auricular nerves supply sensory

innervation.

Etiology

A. The origin of the deformity is not understood. Theories include intrauterine ischemia caused by either an obliterated stapedial artery or a local hemorrhage.

B. No consistent inheritance pattern has been observed. C. Medications associated with ear deformities include

thalidomide, clomiphene citrate, and retinoic acid. D. Five percent of cases have an immediate family

member with a major ear deformity. E. Parents with two affected children have a risk of

recurrence as high as 15% in a subsequent pregnancy.

Associated deformities

“craniofacial microsomia” (first and second branchial arch syndrome)

defects of the external and middle ear; hypoplasia of the mandible, maxilla, zyogomatic, and temporal bones; macrostomia and lateral facial clefts; and atrophy of facial muscles and parotid gland.

urogenital tract abnormalities  hemifacial microsomia, Goldenhar

Syndrome or Treacher-Collins Syndrome.

Branchial arch deformities

Obvious bony and soft-tissue deficit 36.5%, Family perceives it as “significant” 49.4%

Overt facial nerve weakness 15.2% Of these, more than one branch involved 42.6% Macrostomia 2.5% Cleft lip and/or palate 4.3% Urogenital defects 4.0% Cardiovascular malformations 2.5% Miscellaneous deformities 1.7%

classification

timing

Timing is governed by both psychological and physical considerations:

• The child’s concept of body image usually begins to evolve at 4–5 years of age. Psychologically, the child is rarely disturbed with the ear prior to age 7.

• Surgery should be postponed until rib growth affords necessary cartilage volume to permit fashioning of a quality framework.

• By age 6, rib cartilage size is usually sufficient for repair and recognition of the ear as a problem for the child is such that he or she is ready for intervention. At this age, the child is apt to be more cooperative with post-operative care instructions.

Preoperative considerations

• During preoperative planning, one attempts to match the opposite ear with respect to surface topography. (template)

• Consider other facial procedures that may be necessary (i.e., correction of bony deformities, soft tissue deficiency). Specifically, one must take care to preserve the virgin auricular site and keep it free of scar.

• The auricular reconstruction must precede external auditory canal reconstruction when the latter is indicated.

Brent method

1. Creation and placement of a rib cartilage auricular framework .

2. Rotation of the malpositioned ear lobule into the correct position .

3. Elevation of the reconstructed auricle and creation of a retroauricular sulcus.

4. Deepening of the concha and creation of the tragus.

Nagata technique

1. Creation of an auricular framework including the tragus and rotation of the lobule into the correct position (in other words, combining stages 1, 2, and 4 from the Brent technique).

2. Elevation of the reconstructed ear and creation of the retroauricular sulcus

Template

dressing

Post op care

pack the new ear’s convolutions with Vaseline gauze and apply a bulky, noncompressive dressing

I routinely remove them at 5 days.(neligan)– 14 days early infection manifests-local erythema, edema,

subtle fluctuance, drainage Infection--an irrigation drain is introduced below the

flap, and continuous antibiotic drip irrigation given with systemic antibiotics

Skin flap necrosis results from excess tension in an inadequate-sized pocket, tight bolster sutures, or damage to the subdermal vascularity during the flap dissection

sleep on the opposite side

future

Prefabrication- tissue engineering Limitation - skin cover that is taut,

inelastic, and restrictive. the difficulty in accommodating the

great variation in size and shape that must be produced to match the opposite, normal ear.

synopsis

The commonest acquired ear deformity presenting for reconstruction is the partial ear defect.

Apart from acquired ear deformities, microtia is one of the commonest and most complex conditions that present for reconstruction.

Patients with microtia may have associated anomalies

Reconstruction is usually a staged procedure.

Creation of an adequate cartilage framework is key to the success of reconstruction.

Thnx