RECONSTRUCTION OF THE
DAMAGED AURICLE
SOURCE: Dept. of Otolaryngology, UTMB, Grand Rounds
DATE: January 3, 1996
RESIDENT PHYSICIAN: Rusty Stevens, M.D.
FACULTY: Karen H. Calhoun, M.D.
SERIES EDITOR: Francis B. Quinn, Jr., M.D.
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"This material was prepared by resident physicians in partial fulfillment of
educational requirements established for the Postgraduate Training Program of
the UTMB Department of Otolaryngology/Head and Neck Surgery and was not intended
for clinical use in its present form. It was prepared for the purpose of stimulating
group discussion in a conference setting. No warranties, either express or implied,
are made with respect to its accuracy, completeness, or timeliness. The material
does not necessarily reflect the current or past opinions of members of the UTMB
faculty and should not be used for purposes of diagnosis or treatment without
consulting appropriate literature sources and informed professional opinion."
INTRODUCTION
Reconstruction of auricular defects can be challenging for a variety
of reasons. The prominent position of the auricle ensures that any
asymmetries in size, shape or position will be easily noticed. Additionally,
the complex cartilage folds and thin, adherent skin are difficult to reproduce. It is therefore important to have a complete understanding of the available
reconstructive options.
ANATOMY
The auricle is a complex cartilaginous structure with multiple folds,
draped closely with thin skin. The major landmarks include the helix,
antihelix, tragus, antitragus, scaphoid fossa, triangular fossa, concha and
lobule. Anteriorly, the skin has little subcutaneous tissue and is closely
adherent to the cartilage. Inferiorly, the amount of subcutaneous tissue
increases and cartilage decreases to end in a lobule that is primarily skin
and subcutaneous tissue. Posteriorly the skin is much less adherent to
the cartilage. Blood supply to the region is important from a surgical
standpoint and includes the postauricular branch of the external carotid
artery which supplies most of the posterior aspect and a small amount of
the anterior auricle.
Additionally, the occipital artery gives off a branch which supplies part
of the posterior auricle. The anterior blood supply primarily is from the
anterior auricular branch of the superficial temporal artery. Sensory
innervation is supplied by the greater auricular, and lesser occipital nerves
from the cervical plexus as well as the auriculotemporal branch of the
trigeminal nerve and the auricular branch of the vagus nerve. Both extrinsic
(Auricularis anterior, superior, posterior) and intrinsic muscles are present
but serve little or no function in humans.
GENERAL CONSIDERATIONS
As a general rule, if the original parts are available and salvageable,
these will give the best final outcome. Even a near total avulsion may be
salvaged by primary reattachment if a small pedicle of soft tissue remains.(1)
Meticulous debridement and close observation for infection, ischemia or venous
congestion are particularly important in these cases.
Additionally, pre-operative considerations include age, general health,
radiation exposure or tobacco use as well as a complete evaluation for
associated injuries or evidence of residual or recurrent tumor. Above all,
the available options and a realistic assessment of the likely outcome should
be discussed with the patient at length prior to reconstructive surgery.
PARTIAL DEFECTS
Rim Defects
Rim defects can be repaired primarily with a rim advancement flap.(6)
This is a single stage procedure that usually produces excellent results.
A full thickness incision is made in the helical fold from the inferior aspect
of the defect down to the upper portion of the lobule. The rim is then
advanced and closed primarily. Because the lobule is expansile, there is
usually only minimal deformity produced. Larger defects can be repaired using
tubed pedicled flaps.(5,9) These are staged procedures and leave a scar at
the donor site but will also give acceptable results. The initial procedure
involves elevating and tubing a bipedicled flap. The donor site may be
located in the pre or postauricular region or in the neck. The flap width is
determined by the defect size and the length may be up to six times the
width. A central, third pedicle may be preserved if longer lengths are
required or there is concern for the flaps viability. Successive procedures
are performed at 2-3 week intervals to divide each pedicle and transfer that
portion of the flap to the auricle.
Conchal Defects
Conchal defects involving the anterior skin and cartilage can be repaired
with a postauricular "revolving door" island flap.(6) The skin island
includes posterior conchal as well as postauricular skin and is elevated
anteriorly and posteriorly to leave a pedicle in the conchal-mastoid groove.
The "revolving door" is then rotated anteriorly into the conchal defect. The
post auricular donor site can be closed primarily.
Full thickness conchal defects can be closed using a pedicled
myocutaneous flap based on the post auricular artery.7 Skin islands up to
6 x 6 cm can be developed with this technique. The vascular pedicle is
protected by elevating the flap in a subperiosteal plane and only elevating it
superiorly and posteriorly. The auricle is pulled down to the flap and the
donor site is closed primarily.
Upper Third Defects
The upper third of the auricle can be reconstructed using a staged
procedure that involves harvesting costal cartilage to replace the lost rim.
After cutting this cartilage to an appropriate size, it is sutured to the
remaining helical rim and then buried in the adjacent postauricular skin.
In 3-4 weeks, an incision is made approximately O.5 cm above the cartilage
and it is elevated. The posterior aspect is either allowed to heal secondarily
or a Split thickness skin graft is applied.(9)
Middle Third Defects
The middle third can be repaired with costal cartilage in a staged
procedure similar to that described for the upper third. An alternative
method is described by Jackson that uses the bulk of a posteriorly based,
postauricular flap. This flap is elevated and sutured to the anterior aspect
of the defect. In a delayed fashion, the pedicle is divided and the posterior
portion of the flap is folded to resurface the posterior aspect of the
auricle. The donor site is allowed to heal secondarily or is covered with
a skin graft.
Lobule Defects
Naumann describes two techniques to reconstruct lobule defects. The
first is a single stage reconstruction that uses an inferiorly based,
elliptical transposition flap. The width of the flap is twice that of the
desired lobe length. After elevating the flap, it is folded, rotated
posteriorly and inset into the lobule remnant bed. The donor site is easily
closed primarily.
The second technique requires two stages. First the lobule remnant is
inset into the post auricular skin at its edge. Three to four weeks later a
flap is elevated posteriorly and inferiorly with its base at the lobule.
The posterior portion is folded underneath to become the medial aspect of the
lobe and the inferior edges are approximated to free the lobe from the
mastoid skin. The donor site is closed by a local advancement flap or skin
graft.
TOTAL AURICULAR DEFECTS
As mentioned above, the original structures should be utilized if at
all possible. In the case of complete avulsion injury, if the ear is
transported with the patient in a timely fashion, and the surgeon is skilled
at microvascular techniques, these may be employed to primarily reattach the
auricle. Chalain and Jones report success in such a case where a single
arterial anastomosis was made and medicinal leeches were used until intrinsic
venous outflow was established (9 days).(1)
If immediate reattachment is not possible, the cartilaginous framework
can often be salvaged and the auricle reconstructed in a delayed fashion by
debriding the skin and lodging the cartilage in a subcutaneous pocket either
locally or at a distant site (i.e. forearm).(10) The final reconstruction
is performed at a later date by either elevating the cartilage and skin
grafting the posterior aspect or microvascular transfer. Staged procedures
utilizing temporalis and temporoparietal fascial flaps to cover the cartilage
have also been described.(2,6)
In cases where the entire auricular structure is lost (either trauma or
tumor), the standard reconstruction is a staged procedure similar to that
used for microtia malformation. Contralateral costal cartilage is initially
harvested, carved and placed in a subcutaneous pocket. Later procedures
attempt to reconstruct the lobule and tragus, and finally elevate the
reconstructed auricle away from the scalp. An alternative procedure described
by Costa et al. involves implanting a silastic mold into the forearm to form
a prefabricated flap. Later microvascular techniques are used to transfer
the mold and forearm skin to the head. Finally, the use of a prosthetic
auricle is a viable option in some patients and will be discussed later.
TISSUE EXPANDERS
Tissue expanders have been widely used in reconstructive surgery and
are particularly helpful in combination with many of the above mentioned
techniques. A postauricular crescent shaped expander can be used to increase
the amount of thin non hair-bearing skin in this region. The expansion of
skin also promotes ingrowth of new vessels which may improve flaps viability.
However, a dense capsule usually forms around the expander and this may limit
the flexibility of the tissue or blunt the contours of the underlying
cartilage. The capsule can be excised but this is difficult and may injure
the delicate microvasculature of the flap.(8)
PROSTHETICS
The use of auricular prostheses is an option that should be considered
and for many patients may be the reconstruction of choice. Disadvantages
include need for daily care and injury to adjacent skin either from direct
contact or from the strong adhesives needed to hold the prosthesis in place.
Osseointegrated implants have recently been used with success but also have
problems related to local injury, daily care and availability.(11)
CONCLUSION
Reconstruction of the injured or surgically resected auricle can be
difficult. Initially, attempts to salvage as many of the native structures
as possible are of utmost importance. A variety of techniques can later be
employed to reform the lost structures or replace the entire auricle if
necessary.
BIBLIOGRAPHY
1. Chalain, T.d., Jones, G. Replantation of the avulsed pinna: 100
percent survival with a single arterial anastomosis and substitution
of leeches for a venous anastomosis. Plast. and Recon. Surg.
1995;95(7):1275-79
2. Cheney, M.L., Varvares, M.A., Nadol, J.B. The temporoparietal fascial
flap in head and neck reconstrucion. Arch Otolaryngol Head Neck Surg.
1993;119:618-23
3. Costa, H., Cunha, C., Guimaraes, I., Comba, S., Malta, A., and Lopes, A.
Prefabricated flaps for the head and neck: a preliminary report.
British J. of Plast. Surg. 1993;46:223-7
4. Destro, M.W., Speranzini, M.B. Total reconstruction of the auricle after
traumatic amputation. Plast. and Recon. Surg. 1994;94(6):859-864
5. Dujon, D.G., Bowditch, M. The thin tube pedicle: a valuable technique in
auricular reconstruction after trama. Br. J. of Plast. Surg.
1995;48:35-38
6. Jackson, I.T. Local Flaps in Head and Neck Reconstruction. Mosby, St.
Louis. 251-271. 1985
7. Krespi, Y.P., and Pate, B.R. Auricular Reconstruction using Postauricular
Myocutaneous Flap. Laryngoscope 1994;104:778-780
8. McIvor, N.P., Fong, M.W., Berger, K.J., and Freeman, J.L. Use of Tissue
Expansion in Head and Neck Reconstruction. J. of Otolary.
1994;23(1):46-49
9. Naumann, H.H. Head and Neck Surgery: Indications, Techniques, Pitfalls.
Saunders, Philadelphia. 31-69. 1982
10. Schiavon, M., Cagnoni, G. Salvage of an amputated ear temporarily lodged
in a forearm. Plast. and Recon. Surg. 1995;96(7):1698-1701
11. Wilkes, G.H., Wolfaardt, J.F., Dent, M. Osseointegrated alloplastic
versus autogenous ear reconstruction: criteria for treatment selection.
Plast. and Recon. Surg. 1994;93(5):967-979