Reconstruction of the ear can be a complex process. The 3-dimensional nature of the ear with its many curves, peaks, and valleys demand the utmost attention to detail. Yet, as challenging as it may seem, reconstruction of the ear can be made easier and predictable if one understands the surgical principles and anatomy.
The techniques discussed in this article address defects that result from skin cancer excision. More than 1 million cases of basal cell carcinoma, squamous cell carcinoma, and malignant melanoma occur per year in the United States.  A significant portion of these malignancies arise on the ear because of its exposure to the sun. All areas of the external ear are at risk for skin cancer, especially the helix and antihelix areas of the ear. Compared with other cancers, these tend to be more aggressive with higher recurrence rates. Given this setting, the defects on the ear can be relatively large.
Reconstruction of the ear is indicated when a defect is present after skin cancer extirpation. The reconstruction methods discussed in this article all follow the principles of Mohs micrographic surgery. Certain small defects may not need reconstruction and can heal by second intention. This concept is also discussed below. 
The external ear is composed of skin and cartilage with the supporting nerves and blood vessels. The auricular cartilage provides a framework for the entire ear except the lobule. The tightly adherent skin extending from the preauricular sulcus to the helix produces distinct topographical landmarks on the anterior surface of the ear that are important in understanding and describing the ear (see the first image below). The concavities include the triangular fossa, the scapha, the cymba, and the cavum of the concha. The helix, the antihelix, the tragus, and the antitragus form the convexities. The skin on the posterior (medial) aspect of the ear that extends to the postauricular sulcus is less adherent to the underlying cartilage (see the second image below). 
A well-proportioned ear is 50-60% as wide as it is high. The ear is positioned one ear length from the lateral orbital rim, and the top of the ear is level with the eyebrow and tilted back by 20°. 
The auriculotemporal nerve, a branch of cranial nerve V3 innervates the superior aspect of the anterior surface of the ear. The lesser occipital nerve and the great auricular nerve are both derived from C2 and C3. The lesser occipital nerve innervates the superior aspect of the posterior surface. The great auricular nerve innervates the lower portion of both surfaces. The vagus nerve supplies the concha.
The ear is well vascularized, an important feature because most flaps are based on a random blood supply. The superficial temporal artery and the posterior auricular artery are branches of the external carotid artery and supply the anterior and posterior surfaces, respectively.  Because of the rich blood supply and collateralization, anesthetics that contain epinephrine can be used safely.
Reconstruction of the ear has relatively few contraindications. If the patient can tolerate the initial Mohs micrographic surgery, they can usually tolerate the subsequent reconstruction as well, although the complexity of the reconstruction may need to be tailored to the patient's medical state. In patients whose medical condition precludes surgery, other treatment options, such as superficial radiation therapy (SRT), should be considered.
The patient's medical history should be assessed prior to surgery. Aspirin and warfarin increase the risk of intraoperative and postoperative bleeding complications. The use of these medications is not an absolute contraindication for skin surgery, but stopping these treatments prior to surgery is ideal, if possible.