TITLE:
SOURCE: Grand Rounds Presentation, University of Texas Medical Branch,
=
Dept. of Otolaryngology
DATE: September 30, 2010
RESIDENT PHYSICIAN: Susan Edionwe, M.D
FACULTY PHYSICIAN: Vicente Resto, M.D.
SERIES EDITOR: Francis B. Quinn, Jr., MD
ARCHIVIST: Melinda Stoner Qui=
nn,
MSICS
"This material was prepared by reside= nt physicians in partial fulfillment of educational requirements established f= or 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 sho= uld not be used for purposes of diagnosis or treatment without consulting appro= priate literature sources and informed professional opinion." <= /p>
Introduction
Auricular surgery encompasses various kinds of surgical techniques given the initial defect. These defects can be congenital or = acquired in nature. Further, acquired defects tend to either be secondary to trauma or malignancy. It is important for head and neck surgeons to have some knowledge of these techniques as these kinds of patie= nts can be encountered in an otolaryngology practice. To this regard, knowledge= of the anatomy, embryology, and aesthetic evaluation is paramount for an accurate diagnosis and appropriate surgical intervention of auricular deformities.
Anatomy and Embryology of the Auricle
Embryology
Ear development begins during weeks 5 to 6 of gestation with the formation of six mesenchymal swellings or hillocks. The anterior three hillocks and the posterior three hillocks originate from the first and second branchial arches, respectively. These hillocks are situated on either side of the first branchial groove an= d, with tissue growth and development, they fuse to form the auricle and its characteristic shape. The sec= ond arch gives rise to most of the anatomic landmarks of the ear including the helix, scapha, antihelix, antitragus, and the l= obule. The first arch primarily gives rise to the tragus and the helical crus. Complete formation of the auricle = occurs by week 8 of gestation.
Anatomy of the Ear
An understanding of the topographic landmarks and structures of the normal ear= and an assessment of what has been compromised will guide preoperative planning= as to clear identification of the defect and what surgical techniques will be necessary for correction of it. The auricle is a composite of skin and cartilage which, together, form folds and involutions that vary amongst all ears but still hold similar basic propert= ies. The auricle contains el= astic fibrocartilage which is essentially uniform throughou= t the ear in thickness. It is cover= ed by skin on both surfaces. In is important to note that the anterior skin of the auricle is fine, thin, and closely adherent to the underlying cartilaginous framework. There is only a scant amount of subcutaneous fat anteriorly; however, a diffuse subder= mal vascular plane is present and capable of supporting flap viability. The posterior surface is covered w= ith less adherent skin that has two layers of fat as well as a larger subdermal plexus of nerves, arteries, and veins.
As mentioned, there are various convolutions of =
the
auricle that can be identified in the normal ear. The helix is often descri=
bed
as the prominent rim of the auricle that terminates anteriorly in a helical
crus that lies superior to the meatus of the external auditory canal. The antihelix runs interior to the=
helix
and parallels it in course. It
crowns the posterior conchal wall and also terminates in a crus that separa=
tes
anteriorly into superior and inferior crura.
Vascular Supply
The arterial blood supply of the ear originates = from the superficial temporal and posterior auricular arteries with some contributions from the occipital arteries.= The superficial temporal artery arises anterior to the ear and gives= off a superior, medial, and inferior branch that supplies the anterior and anterolateral aspect of the auricle. The posterior auricular artery tra= vels parallel to the post-auricular sulcus and predominantly supplies the posterior auricular surface. The end branches of these arteries extensively anastamose to form a tremendous blood supply that allows for several surgical approaches to the ear. The venous drainage is complementary to the arterial supply and empties into the external jugular vein.
Neurologic Supply
The sensory supply to the auricle consists of fo=
ur
nerves. The primary nerve sup=
ply is
greater auricular nerve of C2 - C3 which supplies the inferior surfaces of =
the
auricle. It is an important
surgical landmark as it travels 8mm posterior to the post-auricular sulcus and can cause significant anesthesia to the ea=
r if
damaged. Conversely, regional
anesthesia to the auricle can be readily accomplished by instilling anesthe=
tic
along its base anteriorly and posteriorly.=
The lesser occipital nerve from the ventral ram=
i
of C2 and C3 supplies the cranial surface or posterior superior surface of
auricle. The auriculotemporal
nerve of the mandibular branch of CN V supplies=
the
anterior surface of the auricle.
Lastly, the conchal bowl and the tragus are supplied by
The auricle has 6 clinically insignificant intri= nsic muscles that are supplied motor innervations by the facial nerve. These muscles are the major and mi= nor helices, tragus, antitragus, transverse, and oblique muscles. Additionally, there are three extr= insic muscles also supplied by CN7 which are the anterior, superior, and posterio= r auricularis muscles.
Aesthetic Evaluation of the Ear
Aesthetic evaluation of the ear is important for preoperative planning and should be documented with standard preoperative photography. This photography includes a frontal view, right and left later= al views, and right and left oblique views along with close up left lateral and right lateral views.
Auricular Measurements
About 85- 90% of ear growth is achieved by 5-6 y=
ears
of age. Although ear height growth continues into adulthood, the width and
distance of the ear from the scalp rarely change after the age of 10. The average ear is 65mm long and 3=
5mm
wide. The ear width is 50-60%=
of
the height. On the lateral view, the superior aspect of the helix lies at t=
he
level of the lateral eyebrow (superior orbital rim). The inferior aspect li=
es at
the level of the base of the nasal alae (nasal
spine). The ear is situated r=
oughly
6 cm from the lateral orbital rim and slopes 15-20o posteriorly =
from
the vertical axis to approximate the nasal dorsum within 15o. Th=
e auriculocephalic angle, the angle between the auricle=
and
the scalp, is most important in the posterior view of the auricle. It is se=
t by
a combination of the angle of the posterior wall of the conchal bowl (90
Cultural differences
There are variations to these measurements espec= ially amongst sex and races. The av= erage Caucasian female ear is 59mm and 32.5mm for height and width, respectively. In persons of A= frican descent, the auricle length tends to be shorter versus persons of Asian des= cent who tend to have slightly longer ears.
Congenital Auricular defects
Congenital
Congenital malformations to the external ear ran=
ge
from deformities of the pinna, including auricular atr=
esia
to stenosis of the external auditory canal. These abnormalities include
Prominauris
Prominauris is one o=
f the
most common congenital defects that occur in 5% of the population. It is autosom=
al
dominant in inheritance and is described as a protrusion of the auricle gre=
ater
than the normal auriculocephalic angle (> 30=
-40o). It is known to be a function of on=
e or a
combination of the following defects: a poorly developed antihelical fold (=
most
common) or formation of excessive conchal cartilage (next common). Poor development of the antihelix =
leads
to no definition between the conchal cavity and the sc=
aphoid
fossa resulting in lateral projection of the upper portion of the helix.
Prominauris has a we= ll documented psychological influence. Studies comparing data before and after corrective surgery for promi= nent ears reveal improved QOL, improvements of self esteem, decreased psychosoci= al anxiety, and decreased anxiety states, specifically in children. As school-aged children are more l= ikely to suffer the psychological consequences of peer ridicule, it is recommended that the ideal age for surgical correction, or otoplas= ty, should occur between the ages of 5-6 years. Further, at this age, children are= about to or have recently started attending school and are able to participate in their own postoperative care.
Acquired Auri= cular defects
Acquired defects of the auricle include those th= at result from trauma and iatrogenic defects resulting from surgical excision specifi= cally with cutaneous malignancies and the resulting d= efect after Moh’s surgery.
Trauma
Given the superficial location of the auricle, i= t is vulnerable to traumatic injury. These include varying degrees of lacerations and injuries from falls, animal bites, car accidents, and sports. In one case series from 1983, human bites were found to be the most common cause of traumatic auricular injury = [1]. A more recent case series found car accidents to be the most common cause of injury [13]. Trauma from burn inju= ry offers a unique challenge. Successful reconstruction of the ear after burn injury depends on the extent of the burn injury and availability of unscarr= ed, healthy tissue to achieve an appropriate construct. However, often times, given the ex= tent of burn injury, this reconstruction is limited by a scarcity of supple, ela= stic skin and fascia. Soft tissue = lost post injury should be classified into the number of tissue layers lost and = the area the ear affected as this will guide surgical repair options.
Moh’s microsurgery
Of the non-melanoma skin malignancies, basal cell carcinoma accounts for 21% of neoplasms of the external ear and temporal bone. In the auricle, BCC accounts for 45-90% of malignancies and SCC for 10% of malignancies. The recurrence rates of BCC and SCC are 1 and 5%, respectivel= y. Indications for Moh’s surgery include: recurrent or incompletely excised basal ce= ll carcinoma (BCC), squamous cell carcinoma (SCC), lesions located in high-risk areas or embryonic fusion planes such as the eyelids, nose, ear, nasolabial folds, upper lip, vermillion border, columella, periorbital, t= emples, preauricular and post-auricular areas. Other indications are: clinically = and histologically aggressive tumors, tumors in cosmetica= lly or functionally important areas, tumors arising in sites of previous radiation, and tumors in patients with basal cell nevus syndrome. Moh’s is particularly useful for recurrent BCC greater than 2cm. Moh’s surgery involves gross curettage of tissue followed by excision of the thin tissue planes with identification of residual tumor using light microscopy. This is done until clear margins a= re obtained. Processing of the t= umor in this manner leaves a fresh tissue defect enabling immediate reconstructi= on after complete removal of disease.<= o:p>
Otoplasty
Otoplasty is the ter= m used to describe surgical techniques for correction of prominauris. Diffenbach first described a technique for surgical correction of prominauris in 1845 = and since its origin, several techniques have developed but the goals of otoplasty, as described by McDowell in 1968 remain the same; protrusion in the upper third of the ear should be eliminated, the he= lix of both ears should be seen lateral to the antihelix from the front view (failure to do so results in “hidden helix”), the helix should = have a smooth and regular contour, the post-auricular sulcu= s should not be markedly decreased or disturbed, the ear should not be placed= too close to the head (esspecially in males), and t= he contours and positions of the two ears should match closely but not be symmetrical.
Today, surgical techniques are divided into cart= ilage sparing versus cartilage manipulating techniques and those that correct the= absent antihelical fold or reduce the excessive conchal bowl. In 1963, Must= arde first described a cartilage-manipulating technique that restored the antihelical fold using permanent conchoscaphal horizontal mattress suture; in 1968, Furnas described a conchal setback technique using permanent conchomastoidal sutures. Today, these techniq= ues, with some variability based on surgeon, are most commonly used in correctio= n of prominauris secondary to an absent antihelix, excessive conchal cartilage, = or a combination thereof.
Technique of Mustarde
This technique was first described in 1959 by
A fusiform post-auri= cular skin incision is created. Per= Lalwani, it is best to excise more skin from the post= -auricular surface than the mastoid surface in attempts to better conceal the scar in = the post-auricular sulcus. The purpose of excising this ellipse of= skin is to remove the predicted skin excess that results once the ear is retropositioned. Once this fusiform of skin is excised, the posterior skin = is elevated from the perichondrium over the helix, antihelix, and conchal cartilage.
Once the posterior aspect has been addressed, the anterior aspect should be addressed before suture placement. As the anterior skin is tightly ad= herent and hydrodissection from infiltration with local injection is not fully adequate to release the anterior skin, an instrument needs to be introduced into the anterior surface of the ear to release the = skin and allow for access to the anterior cartilage for scoring through the perichondrium. Access to the = ear is done by creating an access point or “slot” at the tail of the h= elix posteriorly. Once this is don= e, access to the anterior surface of the ear is possible and a tunnel over the projec= ted antihelical fold is created (can be done with fine scissors or a Freer elevator). With the Mustarde technique, the car= tilage in this area needs to be weakened to allow for pliability as the fold is created. An abrading tool (otoabrader, nasal ra= sp, Adson-Brown forceps, dermabrader= with a small diamond fraise, etc) is passed into this tunnel and several ge= ntle pass with the tool is used to weaken the cartilage. Care should be taken no= t to over-abrade the cartilage (ie: full thickness cartilage scoring) as this can lead to a sharp-edged antihelix.
Securing of the antihelical fold is done with permanent suture (4-0 Mersilene). Horizontal mattress sutures are pl= aced in the posterior surface from medial perichondrium through cartilage and lateral perichondrium. Extrem= e care should be taken not to pierce the anterior skin. The sutures should be plac= ed perpendicular to the demarcated antihelical fold so when they are tightened= a well-rounded antihelical fold is created.&= nbsp; Further, they should be parallel to the helix at the lateral extent = of the antihelical fold, as the helix and antihelix run parallel in fashion.
Once complete, the wound should be irrigated and= the post-auricular incision should be closed with absorbable suture. Of note, a tension free closure is paramount in this location as it is highly prone to keloid formation. The dressing is important to prevent hematoma formation and it must provide adequate pressure to obliterate any dead space. Pressure facial dressing or mastoid dressings have been suggested with petroleum gauze or antibiotic ointment gauze/cotton applied directly to the ear.
Technique of Furnas
This technique was first described in 1969 by Fu=
rnas
as a solution to excessive conchal cartilage seen with prominauris and is o=
ften
done in adjunct with the Mustarde technique.
Three to four permanent horizontal mattress sutu= res (3 or 4-0 Mersilene) are then placed from the late= ral third of the concha cavum and cymba (parallel with the natural auricular curvature) through the cartilage and lateral perichondrium to the mastoid <= span class=3DSpellE>periosteum. Extreme care is taken to not pierce the anterior conchal skin in the process. When these sut= ures are tightened, what was once the wall of the concha will be converted into a longer conchal floor. Again, tension-free closure of the post-auricular incision is important to prevent keloid formation.
Principles of Auricular Reconstruction
Secondary Intention
This is an ideal option for patients who have had previous radiation therapy, are smokers, diabetics, have coagulation disord= ers, or some other form of microvascular compromise = and are poor candidates for grafting to this area as compromise of flap circula= tion is a concern. Patients who have medical conditions that prohibit surg= ery and have absolute contraindications to primary repair are also prime candid= ates for this technique. Defects i= n the concavities of the ear (ie: conchal bowl and triangular fossa) are ideal as these defects heal well and leave a nearly imperceptible scar. Defects o= n the antihelix, a flat area of the ear, can also be amendable to secondary inten= tion with fair result as long as there is underlying cartilage support. Secondary intention is not ideal for defects of the convex areas of the ear, specific= ally the helix, as these result in permanent and obvious notching.
Assessing wound size, skin color, and depth help= to determine cosmetic outcome of secondary intention healing. Smaller defects (1cm or less) heal better than larger ones and form smaller scars when they contract that blend with other skin imperfections. Size of the defect is especially important in darker or tel= angiectatic skin as scar tends to be hypopigmented, thus ma= king a larger scar more noticeable. Likewise, more superficial wounds heal better than deeper wounds in = the same area.
One concern of healing by secondary intention is= a protracted course of healing. This can take several weeks depending on the size = of the defect and can be challenged by a lack of tissue laxity and, given the = poor vascularity of cartilage, presence of exposed cartilage (lacking overlying perichondrium) in the defect. In the case of cartilage exposure, heal= ing can be aided by fenestrating the exposed cartil= age thereby exposing it to the vascular-rich dermis of the posterior auricular skin.
Daily wound care is important and can be viewed,= by some, as a down-fall to this method. The goal is to prevent crusting and drying of the wound that can del= ay healing, worsens scar formation, and de-epithelize areas of new epithelization with debridement of crusting or removal of dry or adherent dressing. Daily dressing changes with an antibacterial ointment applied to the surface is recommended.
Full thickness skin grafts (FTSG)/
Skin grafting is, to some, a preferred option for defects of the conchal bowl and antihelix that are generally < 2.0cm in size. A FTSG is often preferred over a STSG as it tends to be a better color match for defects in the auricle and has a lower potential for contracture. FTSG can be harvested from the contralateral pre or post-auricular skin or = the supraclavicular area. FTSG is a better match than STS= G not just for color, but texture and thickness. Of concern is grafting over area= s of exposed cartilage. It is recommended that areas of conchal cartilage should be excised to allow for well-vascularized area for the graft. Excising this cartilage should not compromise the overall integrity of the structural support of the auricle.<= /p>
Post-auricular
This technique was first described by Masson in = 1972 in plastic surgery literature. It has been traditionally used for defects of the anterior conchal cartilage b= ut has been performed by some for defects of the scaphoid= fossa and antihelix. It is a = fasciocutaneous flap vs <= span class=3DSpellE>myocutaneous transpositional flap that involves pedicled post-auricular skin as a= cover for anterior auricular defects. It is believed that the post-auricular muscle and fascia are incorporated into this flap and perforators from the post-auricular artery supply this area. = Defects corrected with this method are usually 2cm or less in size.
To execute this flap, a template is made of the = defect and the auricle is reflected anteriorly to mark the donor site (post-auricu= lar skin including the post-auricular sulcus). This= post-auricular flap is incised, forming an island of skin with a subcutaneous pedicle. A slit incision is begun at that posterior aspect of the defect and carried to the post-auricular sulcus creating a through-and-through defect for pass= age of the flap from posterior to anterior. This incision is extended to the base of the flap and undermining is then carried out in the plane of the mastoid periosteu= m. Once this is complete, the flap and its pedicle are pulled through the inci= sion and laid on the anterior defect and this is closed with fine nonabsorbable sutures. The secondary post-auricular defect is closed primarily.
Antia Buch= condrocutaneous advancement flap
This flap, first described in 1967 by Antia and Buch, is used f= or reconstruction of helical defects of 3 cm diameter or less. In this method,= the anterior skin and cartilage are incised at the base of the helical rim form= ing chondrocutaneous flaps. The posterior skin is not incised; rather the post auricular skin is elevated from the perichondrium and serve= s as a vascular pedicle and preserves the blood supply to the helical rim. The <= span class=3DSpellE>chondrocuntaneous flaps are raised unilaterally or bilaterally (depending on the defect).&nbs= p; Once raised, the ends of these helical margins are re-approximated (directly brought together). Posterior standing cone deformities formed are corrected with Burrow’s triangles. Aur= icular height will undoubtedly be decreased with this technique as the length of t= he repaired defect will have been transferred to the pulled-up lobule. If the discrepancy between both ea= rs is marked, then the contralateral ear may need to be augmented with a wedge excision and closure.
Bipedicled “tubed” flap
This flap is used for longer helical rim defects >2.5cm in size. It can be = based in the pre, post, or retro-auricular skin, depending on the location of the helical defect. It is traditionally a three-staged process and begins with raising a bipedicled, tube shaped flap. This fl= ap is adhered over the defect with its pedicles intact. The underlying secondary defect at= the donor site is close primarily. Stage two and three involve separation of one pedicle and insetting = it into the defect and each is done 3 weeks apart.
Banner transpositional flap
This is a supra- or pre-auricular based flap tha=
t can
be used to cover the helical root (proximal helix) or superior helical
rim. Defects of the helical r=
oot
can be covered in a single staged fashion.=
Essentially, a flap is raised in the pre-auricular skin with its base
contiguous with the defect. I=
t is
then secured to the defect and the secondary defect is closed primarily.
Mladik Pocket Principle
This staged principle was first described by
Double lobed flap
An absent lobule can be reconstructed using this
anteriorly-based auriculomastoid flap. A bilobed shaped flap is delineated on the auriculomastoid skin and raised with its base functio=
ning
as the anterior attachment of the neo-lobule. The neo-lobule is formed when=
the
raised flap is folded in on itself and attached the superior auricle. The
secondary defect is closed primarily.
Complications
Complications for auricular surgery can be divid= ed into early (occurs 24-96 hours) and late complications including aesthetic complications based on procedure. Hematoma is one feared early complication as it can lead to skin and/or cartilage necrosis with ear disfigurement. A compliant of ear tightness or pain should prompt inspection of the ear. This complication can be prevented= establishing adequate hemostasis intrao= peratively and using pressure dressings postoperatively.
Infection, evidenced by pain/tenderness and sign= s of inflammation, usually occurs by day three or four. Treatment should be prom= pt to avoid supparative chond= ritis and consists of systemic antibiotics with coverage for staphylococci, streptococci, and Pseudomonas aeruginosa. Chondritis is heralded by signs of obvious infection including severe edema and pain. Treatment will require empiric IV antibiotics, drainage, debridement, and a wound culture to target therapy.
Other early complications include suture extrusi= on, which is of particular concern with otoplasty (= can also be a late complication along with suture granulom= a). Skin necrosis is another complicat= ion resulting from vascular compromise due to pressure necrosis (excessively tightened sutures or tight ear dressings) or inappropriately undermined skin flaps (too superficial). Over-tightened sutures and ear dressings should be avoided. Skin necrosis can be treated reduc= ing pressure over the skin and applying antibiotic topical cream. Similarly, venous congestion of fl= aps arises because the venous outflow is compromise by clot formation or venous= compression. Treatment includes hyperbaric oxyg= en, removal of obstructive sources, or medicinal leeches.
Examples of late complications include hypertrop= hic scar or keloid scar formation. These develop when the wound has healed and are a direct result from wound closure under tension. They are less common than other complications, however. Management of hypertrophic or keloid scars typically involves intralesional steroid injections. Management with exc= ision alone has been shown to yield 45-100% recurrence rate. The best form of prevention is a t= ension free closure.
Aesthetic complications are also late complicati= ons that vary depending on the surgical technique employed. With otoplast= y, some aesthetic complications include a sharp-edged antihelical fold (due to over-scoring of the cartilage) and hidden helix (the helix is position medi= al to the antihelix on a frontal view of the face). With otoplast= y, telephone ear deformity (the upper and lower ear projecting more prominently than the middle ear) results from overcorrection of the middle third of the prominent ear. Reverse teleph= one ear deformity occurs when the mid-auricle protrudes after overcorrection of= the upper and lower ear. Asymmetry between the left and right ear is a general complication of any technique as well as malpositionin= g, a close-fitting auricle, or a collapsed ear. Aesthetic complications are corrected with revision surgery.
Summary
Auricular reconstructive surgery encompasses a v= ariety of techniques for congenital and acquired defects. It is important for the surgeon to understand some of the prevalent techniques of surgical repair and have the= m in their arsenal of surgical repair options.&= nbsp; Furthermore, it is my recommendation that the aforementioned techniq= ues along with others be reviewed in conjunction with pictures/diagrams to obta= in a complete understanding of the procedures.
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