CHAPTER 5 The ear is situated posterior to the temporomandibular joint and projects over the mastoid process of the temporal bone on the cranium. Therefore the ear can almost always be positioned correctly despite facial asymmetry. However, surgeons must understand the need for flexibility if reference facial landmarks are used to correctly position the ear. They must remember that the two profile views of the patient are very rarely seen simultaneously and that the position of the two ears is only seen together from the frontal and posterior views. Thus some compromise regarding the position of the ear may be acceptable in the horizontal plane but never in the vertical plane. The distance between the lateral canthus and the auricular area is often shorter on the affected side in cases of facial asymmetry. Symmetry in the vertical plane is not only critical for a good aesthetic result from the frontal view but also for adequate support for glasses. Pearl 1. The patient should put on a pair of glasses to appreciate the correct level of the ear. The correct vertical position of the ear can also be appreciated from the posterior view, because it excludes the asymmetry of the face. 2. Some patients who routinely wear glasses before their ear reconstruction find a clever solution, particularly when presenting with bilateral microtia. The mandible will either be corrected early if severe or may be delayed until after the ear reconstruction. When it is corrected after ear reconstruction, an asymmetry of the inferior part of the ear will always be present. Because the ear is located not on the face but on the cranium, it is possible to correctly analyze and use the fixed landmarks of the normal side. However, surgeons should warn their patients that although the ear has been placed in the correct skeletal position, residual asymmetry will be present until facial asymmetry is also corrected. The development of the mastoid is particularly important, because it will support the reconstructed ear. In cases of underdevelopment of the mastoid, in which the hollow is not very deep, a block of cartilage can be added beneath the inferior part of the framework from the antitragus to the intertragal notch (see Chapter 3.) This projection piece, known as PIII, adds projection to the lobule and antitragus and limits the descent of the framework into the mastoid hollow. When the depression is severe, the surgeon cannot expect the mandibular correction to affect the auricular depression, because the ear is located behind the temporomandibular joint and ramus of the mandible. This raises the question of how and when this depression can be corrected. In severe cases we perform fat grafting in two or three procedures to improve the quality of the hypoplastic skin before ear reconstruction. Perhaps in the future vascularized tissue transfer could be considered for reconstructing this hollow. Bone grafting or the use of alloplastic material has also been suggested. For each of these techniques, the optimal time needs to be determined: before the first stage, during the second stage, or after completion of the ear reconstruction. A low hairline is commonly seen in HFM. Even when no clear signs of facial asymmetry are obvious, we have found that the absence of a preauricular sideburn is pathognomonic for the syndrome. Usually, if sideburns are absent, some evidence of asymmetry is present, even if minor. We have also found a high incidence of low hairline in Treacher Collins–Franceschetti (TCF) syndrome. In this condition the sideburn will usually be anteriorly projecting onto the cheek, and the course of the superficial artery is very commonly ectopic. Preoperative Doppler ultrasonography is very useful in these cases. If, after determining the ideal position of the ear, part of the ear is placed under the postauricular hairline, the use of temporal fascia must be considered (see Chapter 4). We routinely use a “harmonic scalpel” to elevate the fascia, which facilitates the dissection. The hairy skin and temporal fascia may be removed only during the second stage in cases in which a small amount of hair may cover part of the upper part of the helix. There is a spectrum of severity of low hairlines. The non-hair-bearing skin located in the auricular area is always preserved and will be used to partially cover the inferior part of the framework at a level that will vary according to skin laxity. Lasers may be used in some situations to prepare the auricular area, particularly when a low hairline is present and the temporal fascia cannot be used. Nevertheless, because the scalp is not as thin as the retroauricular skin, a laser alone will not give the skin potential needed to follow the contours of the framework. That is why in the following case we used tissue expansion before performing the laser treatment. In addition, laser treatment is more effective when used on the hair-bearing skin with a tissue expander in situ. This is most likely the result of the relative ischemia and sparsity of the hair follicles undergoing laser treatment. In cases of microtia, the superficial temporal artery can be ectopic; part of the artery is located under the ideal location of the ear. Because it is localized and protected during the first stage, it is advantageous to elevate the framework without adherent soft tissue, preventing damage to this ectopic artery. Remnants are considered ectopic when they are located outside of the ideal position of the reconstructed ear. Drawing the ideal location of the ear first will help to determine whether the remnants can be used without compromising the ideal position of the ear. The remnants can frequently be used if they are ectopic but in the auricular area. We commonly encounter two different situations: ectopic remnants without an auditory canal and ectopic remnants with an ectopic auditory canal. If the ectopic remnants are too far from the ideal position of the ear and cannot be used, they should be excised.
Particular Cases of Microtia
PARTICULAR PROBLEMS
Asymmetrical Face
Asymmetry of the Zygomatic Area
Cervical Spinal Cord Malformations
Hypoplasia of the Mandible
Hypotrophy of the Mandible
Hypoplasia of the Mastoid
Low Hairline
Laser Hair Removal for Low Hairlines
Ectopic Artery
Ectopic Remnants
Ectopic Remnants Without an Auditory Canal