Page 46 - Read Online

Page 2 of 8 Rosi-Schumacher et al. Plast Aesthet Res 2022;9:11 https://dx.doi.org/10.20517/2347-9264.2021.64

[1,2]
common location in over 50% of auricular skin cancers . The ear’s location and projection render it
particularly susceptible to environmental exposures and ultraviolet radiation that increase the risk of
developing a cutaneous malignancy. Squamous cell carcinoma is more common than basal cell carcinoma
[2-4]
to present on the ear, and cutaneous melanoma is relatively rare . Mohs micrographic surgery is often
used to excise nonmelanoma cutaneous malignancies in this region to allow for oncologic resection with the
[5]
least loss of normal tissue and form . The variable outcomes resulting from this procedure require
experienced reconstructive surgeons with the ability to work with defects of diverse sizes and locations.

Auricular reconstruction focuses on structure and function, restoring anatomical landmarks, and providing
a cosmetic result . Fibrocartilage provides mechanical support to the upper two-thirds of the ear, while the
[6,7]
lower third of the ear is composed of skin over fibrofatty tissue. In addition, the loose layer of connective
tissue and adipose between the skin and perichondrium present on the posteromedial surface of the auricle
renders the skin more mobile and readily available for grafts and flaps for the reconstructive surgeon. This is
in contrast to the anterolateral surface of the auricle, which is tightly adherent to the underlying
perichondrium.

Understanding normal auricular architecture, orientation, and aesthetic relationships can assist in
preoperative planning and assessment of defects. The average adult ear is 55 to 65 mm long and has a width
of approximately 55% of its length . Facial features provide landmarks for the ideal auricular position. The
[8,9]
inferior point of the lobule should be at the level of the subnasale and the superior point of the upper helical
[10]
rim should align with the level of the superior orbital rim or upper tarsal crease . The vertical axis of the
[11]
ear is inclined 15-20 degrees posteriorly . The protrusion of the auricle from the scalp should range
between 1-2 cm at a 25-35 degree angle . The classically described three regions of the ear have been
[9]
defined by anatomic borders [Table 1]. The upper third of the ear is defined as the portion superior to the
concha cymba and above the Frankfort horizontal line. The upper third of the ear represents an important
functional structure for those patients who use behind-the-ear hearing aids or wear glasses. The middle
third of the ear represents the space between the concha cymba and the start of the lobule. The lower third
of the ear is known as the lobule and is located below the level of the intertragal notch. The vascular supply
of the ear comes from branches of the superficial temporal artery and posterior auricular artery, which
come together in a complex network of vessels [12,13] . Auricular tissue viability after trauma and auricular flap
reconstruction is made possible by these multiple anastomoses and perforators of the superficial temporal
and posterior auricular arteries . The external ear receives sensory innervation from several sources . The
[15]
[14]
anterior auricle and tragus are innervated by the auriculotemporal nerve (Cranial Nerve V3). The inferior
surface and lobule are supplied by the great auricular nerve (C2-3). The superior cranial surface of the ear is
innervated by the lesser occipital nerve (C2-3). The posterior inferior external auditory canal and inferior
conchal bowl are innervated by the auricular branch (Arnold’s nerve) of the vagus nerve (Cranial Nerve X).

It is helpful to analyze defects of the ear by depth, layer involved, and size. If a defect is limited to the
cutaneous layer, secondary healing or primary closure may be best. Tension-free closure should be achieved
and may necessitate trimming of underlying helical cartilage. In regions with less skin laxity, usually the
anterior or lateral surface of the ear, skin grafting represents an option for defect coverage. However,
exposed cartilage without healthy overlying perichondrium will not support a skin graft, and excision
should be considered. Skin grafts should be fenestrated and secured with bolsters. The remainder of more
complex ear defects are commonly classified by the affected anatomical regions.

DEFECTS OF THE UPPER THIRD
Defects smaller than 1.5 cm can be converted to a full-thickness wedge excision and closed primarily in