Microtia

Microtia, the absence, from birth, of an ear, affects about 1 in 6000 children worldwide. The figures are estimated at one in 4,000 in the Japanese and as high as one in l:1200 births in Navajo Indians. The right side is more commonly affected than the left and males are more often affected than females.

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In one in ten microtia cases, both baby's ears will be affected. The problem that results in microtia occurs in the womb about 8 weeks after the baby is conceived. The most likely cause is an interruption of the blood supply to the area which will form the ear. Microtia is sometimes seen as an isolated problem or sometimes as part of a syndrome such as Goldenhar syndrome, hemifacial microsomia or Treacher Collins syndrome.

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There is usually hearing loss on the affected side as the middle ear is underdeveloped. If only one side is affected, then a hearing aid is not normally needed. When the condition affects both sides, treatment to improve the hearing is important. If bone-anchored hearing aids are to be used, it is very important that the aids are properly positioned so as not to compromise the tissues for autogenous ear reconstruction.

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Embryology

A primitive ear shape is recognizable in a 50 day old embryo. The ear forms initially in the neck region and moves upwards onto the head by week l0. In many birth abnormalities involving the ear, this migration is disturbed and the ear remains low-set.

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At birth, a baby’s ear is approximately 66% of the length and 76% of the width of an adult ear. By the age of 6, it has grown to about 90% of adult proportions.

The problem that results in microtia occurs in the womb about 7-8 weeks after the baby is conceived. The most likely cause is an interruption of the blood supply to the area which will form the ear. Microtia is sometimes seen as an isolated problem or sometimes as part of a syndrome such as Goldenhar syndrome, hemifacial microsomia or Treacher Collins syndrome.

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Classification

There is great variety in the shape of underdeveloped ears. Sometimes there is little tissue present at all (anotia). Total anotia is rare; there is no ear structure whatsoever, and a very low hairline. In most cases of microtia there is a small fold of skin and cartilage at the site where the ear should be, with a small, misplaced ear lobe hanging from it.

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In a small number of patients, a narrow strip of normal skin separates two small ear remnants (two remnant microtia) and there is usually facial nerve weakness on the affected side. In conchal microtia, a good part of the upper ear is developed but abnormally folded.

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Surgery

Treatment for microtia is not essential, and some patients do not wish to have the defect reconstructed. For the rest, there are two reconstructive options - to have the ear rebuilt from their own tissues (autogenous ear reconstruction) or to have a prosthetic or false ear anchored to the bone of the side of the head by titanium fixtures (a bone-anchored prosthesis). Patients with anotia usually also require lobe reconstruction.

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The gold standard of ear reconstruction is an ear of carved autogenous costal cartilage. It is usually possible to mimic the opposite normal ear in shape and size. Results have improved enormously in recent years. The ideal age for surgery is over the age of 9 but if the patient is being teased, or if there are other pressures to have the reconstruction carried out a little earlier, it is possible to proceed, although the costal cartilage used to carve the replacement ear is not so plentiful and the result is occasionally not as good as it could have been. Nevertheless, almost all patients prefer this technique, since the aesthetic results are now very good.

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There is no upper age limit to autogenous ear reconstruction, although the likelihood that the cartilage might calcify and become harder to carve (like bone) increases slightly with age. If a bone-anchored prosthesis is to be used then the bone at the ear site needs to be of adequate thickness to accept the fixtures.

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Autogenous reconstruction for microtia is best carried out on previously un-operated sites. Earlier surgery can remove valuable skin and causes scars which can interfere with the blood supply to the new ear. Without realising that they are compromising the final result, it is not uncommon for well-meaning surgeons to perform interim “tidy up” procedures, such as lobe or lop ear set-back, in an attempt to improve the appearance of the ear site until the child is old enough for a formal reconstruction. All such attempts make definitive surgery more difficult, at best, and at worse they spoil the final result and should be strongly resisted.

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Books

Gault DT
Total Reconstruction of the Pinna - a chapter for Scott Brown's Otorhinolaryngology, Head and Neck Surgery, 7th Edition Arnold

Gault DT and Rothera M
Management of Congenital Deformities of the External and Middle Ear - a chapter for Scott Brown's Otorhinolaryngology, Head and Neck Surgery, 7th Edition Arnold

Gault DT
Reconstruction of the ear - a chapter for Principles and Practice of Head and Neck Oncology
Editors Peter Rhys Evans, Patrick Gullane & Paul Montgomery. Martin Dunitz 2003 Winner for George Davey Howells Memorial Prize for most distinguished published contribution to the advancement of Otolaryngology during the preceding five years.

Relevant publications

Chana JS, Grobbelaar AO & Gault DT. (1997)
Tissue expansion as an adjunct to reconstruction of congenital and acquired auricular deformities.
British Journal of Plastic Surgery 50:456-462

Harris P, Ladhani K, Das Gupta R and Gault DT. (1999)
Reconstruction of Acquired Subtotal Ear Defects with Autogenous Costal Cartilage.
British Journal of Plastic Surgery 52: 268-275.

Gault DT. (1998)
Ear Reconstruction : Pitfalls and Tips
Face 6: 15-16

Sabbagh W, Withey S and Gault DT (1999)
A simple alternative to ear reconstruction (letter)
British Journal of Plastic Surgery 52:80-81.

Chana JS, Grobbelaar AO and Gault DT (1998)
Tissue expansion: a useful adjunct to auricular reconstruction
Face 6: 65-68.

Gault D. (1999)
Reconstruction for microtia.
Journal of Laryngology and Otology Supplement no 23. Vol 113, page 27.

Botma M, Aymat A, Gault D, Albert D
Rib graft reconstruction vs Osseointegrated prosthesis for microtia: A significant change in patient preference.
Clinical Otolaryngology. 2001, 26, 274-277

Lawson K, Waterhouse N, Gault DT, Calvert ML, Botma M, Ng T.
Is hemifacial microsomia linked to multiple maternities?
British Journal of Plastic Surgery 2002 55, 474-478

Sabbagh W and Gault D
Location, location, location
Journal of Laryngology and Otology; 2004 118: 738-740

Bajaj Y, Wyatt M, Gault D, Bailey M, Albert DM
How we do it: BAHA positioning in patients with microtia requiring auricular reconstruction
Clinical Otolaryngology 2005 30: 468-471.

Horlock N, Vogelin E, Bradbury ET, Grobbelaar AO, Gault DT
Psychosocial outcome of patients after ear reconstruction - a retrospective study of 62 patients.
Annals of Plastic Surgery 54: (5): 517-524 2005

Vadodaria S, Mowatt D , Giblin V, Gault D
Mastering ear cartilage sculpture: the vegetarian option
Plastic and Reconstructive Surgery 116(7), Dec 2005 2043-2044 Annals of Plastic Surgery 54: (5): 517-524 2005

Gore S, Myers S, Gault D
Mirror ear: a reconstructive technique for substantial tragal anomalies or polyotia
Journal of Plastic, Reconstructive and Aesthetic Surgery 59, 499-504 2006

Beckett KS and Gault D
Operating in an eczematous surgical field; Don't be rash, delay surgery to avoid infective complications
Accepted by the British Journal of Plastic Surgery 2006

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Ear Reconstruction