Reconstruction of the ear

7 Reconstruction of the ear







Historical perspective


Ear reconstruction was first referred to in the Susruta Samhita,1 where a cheek flap was suggested for repairing the earlobe. As early as 1597, Tagliacozzi described repair of both upper and lower ear deformities with retroauricular flaps.2 In 1845, Dieffenbach described repair of the ear’s middle third with an advancement flap3 (see Fig. 7.44, below). This may occasionally have application today.


This early work focused mainly on traumatic deformities. However, by the end of the 19th century, surgeons began to address congenital defects, particularly prominent ears.4


The origin of microtia repair had its significant beginnings in 1920, when Gillies buried carved costal cartilage under mastoid skin,5 then separated it from the head with a cervical flap. Ten years later, Pierce modified this method by lining the new sulcus with a skin graft and building the helix with a tubed flap.6 In 1937, Gillies repaired more than 30 microtic ears using maternal ear cartilage7; these were found to resorb progressively.8


Experiencing the same frustration as others,912 Steffensen13 used preserved rib cartilage to produce excellent results, but later reported progressive resorption of the same cartilage frameworks.14


A major breakthrough came in 1959, when Tanzer used autogenous rib cartilage, which he carved in a solid block.15 His excellent results have persisted over the years.16


In an effort to circumvent large operations, Cronin (1966) introduced silicone ear frameworks,17 but found that, similar to other inorganic implants, e.g., polyethylene, nylon mesh, Marlex, polyester net, and Teflon, they suffered a high incidence of extrusion.18,19 Initially, Cronin minimized this problem by providing fascia lata or galeal and fascial flaps for extra autogenous rim coverage,20 but later, when he found that the alloplastic frames still extruded, he discontinued this practice.


In spite of some investigators’ enthusiasm for Medpor frameworks,21,22 these foreign substances tend to encounter the same problems that have plagued silicone. Most recently, a patient came to my consultation with an infected sinus tract that had been draining from her Medpor implant for 2 years; another patient presented with three separate exposed areas of Medpor in his reconstructed ear. On the other hand, once safely past the 10th postoperative day, I have never lost an autogenous ear framework in a microtia patient; only one has been lost in a trauma patient with poor compliance with postoperative instructions.23 To date, more than 70 of my reconstructed ears have survived major trauma.


For many years there has been considerable interest in creating a “prefabricated” framework from autogenous cartilage in order to circumvent the necessity to fabricate an ear framework during a prolonged reconstructive procedure, and to attempt to eliminate the variability of the surgeon’s artistic ability to create a realistic ear framework from rib cartilage. Young24 and Peer25 first conceived the idea of “framework prefabrication” prior to the actual auricular reconstruction back in the 1940s. This innovative technique was accomplished by means of “diced” pieces of autogenous rib cartilage which were placed in a fenestrated two-piece, ear-shaped vitallium mold which in turn was banked in the patient’s abdominal wall. After several months they retrieved the banked mold, opened it, and harvested the framework of cartilage chips, which had united by connective tissue which had grown through the mold’s openings. However, the results were not consistent, perhaps because contraction of the fibrous tissue surrounding the multiple cartilage islands distorted the resultant framework.


Interest in this “prefabrication” concept has been rekindled via modern “tissue-engineering” techniques in which cartilage cells are grown in the laboratory and seeded upon a synthetic, biodegradable ear form which is then implanted beneath the skin of a mouse.26 The early results are interesting, but it should be noted that the trial work is not being carried out under the same conditions as in a clinical human ear reconstruction – the investigators’ frameworks are being placed under the very loose skin of an animal’s back, whereas in human ear repair, the new framework must be placed underneath snug skin just in front of the hairline in the ear region.


Although these new laboratory studies are intriguing, unless a very firm, substantial three-dimensional framework can be produced from autogenous tissues, it will likely suffer the same consequences I observed for frameworks created by Young and Peer’s method, i.e., flattening out under the restrictive, two-dimensional skin envelope under which the framework must be placed to complete the ear reconstruction. The other obvious limitation of “prefabricated” ear frameworks is the difficulty in accommodating the great variation in size and shape that must be produced to match the opposite, normal ear. When sculpting directly from rib cartilage, these limitations do not exist because the surgeon creates the required specific size and shape each time.


However, I have long been intrigued with the concept of creating a living “prefabricated” ear framework, and began collaborating with researchers several years ago27 to explore the possibilities of bioengineering firm, autogenous cartilage frameworks, to see if some of the above-mentioned limitations can be overcome.28 Our direction involves growing autogenous costal cartilage in varying-sized molds made from “idealized” frameworks that I have sculpted and cast. But to fill these molds with chondrocytes obtained by digesting a large volume of rib cartilage would merely be reproducing Young and Peer’s work by newer technology. Our goal is to exploit the technology using a small piece of cartilage (perhaps obtained by biopsy from the microtia patient at age 3–4 years, when neochondrogenic potential is high), then efficiently to extract the chondrocytes, expand them in culture, and infuse them into the ideal matricial substrate within the ideal ear framework mold for that specific patient. Once generated to satisfaction, the engineered framework would then be “banked” under the patient’s hairless periauricular skin as the first reconstructive surgical phase. For this technique to be successful, the major problems that must be overcome are replicating sufficient chondrocytes from a small cartilage sample (25–50 million cells/mL are needed for neocartilage formation in a construct, and the ear mold volume is about 5 cc), and the ability of those chondrocytes to regenerate firm cartilage matrix so that the engineered framework can withstand the pressure caused by the constraints of a two-dimensional skin cover that is taut, inelastic, and restrictive.


In my experience, until tissue engineering evolves beyond the aforementioned problems, sculpted autogenous rib cartilage remains the most reliable material which produces results with the least complications.16,23,2932 Furthermore, rib cartilage provides the most substantial source for fabricating a total ear framework. Although contralateral conchal cartilage has been used for this purpose,33,34 it seems best to reserve auricular cartilage for repairing partial ear defects, for which considerably less tissue bulk is needed.



Anatomy


The ear is difficult to reproduce surgically because it is comprised of a complexly convoluted frame of delicate elastic cartilage that is surrounded by a fine skin envelope. The denuded cartilage framework conforms almost exactly to the ear’s surface contours except for its absence in the earlobe, which consists of a lobule of fibrofatty tissue rather than cartilage.


In most microtic vestiges, the presence of this lobule tissue is a valuable asset in the repair (Fig. 7.1; see Fig. 7.13). When the lobule is lost in total ear avulsions, it is best recreated by shaping the bottom of the carved ear framework to resemble the lobe.



The ear’s rich vascular supply comes from the superficial temporal and posterior auricular vessels, which can nourish a nearly avulsed ear even on surprisingly narrow tissue pedicles.


The sensory supply is chiefly derived from the inferiorly coursing greater auricular nerve. Upper portions of the ear are supplied by the lesser occipital and auriculotemporal nerves, whereas the conchal region is supplied by a vagal nerve branch.


Understanding this anatomy facilitates blocking the ear with local anesthetic solution. First, the greater auricular nerve is blocked by injecting a wheal underneath the lobule. After awaiting its effect, one continues injecting upward along the auriculocephalic sulcus, around the top of the ear and down to the tragus. Finally, the vagal branch can be numbed without discomfort by traversing the conchal cartilage with a needle placed through the already anesthetized auriculocephalic sulcus to raise a wheal of solution just behind the canal.



Practical embryology and understanding the middle-ear problem


At consultation, parents of a microtic infant are usually most concerned with the hearing problem. They either think that the child is completely deaf on the affected side or that hearing can be restored by merely opening a hole in the skin. As these are misconceptions, the physician can do much to alleviate parent’s anxieties by fundamentally explaining ear embryology.


As the human ear’s receptive (inner) portion is derived from different embryologic tissue than the conductive (external and middle) portion, the inner ear is rarely involved in microtia and these patients have at least some hearing in the affected ear.


The problem is conduction. This is blocked by the malformed middle and external ear complex. Typically, these patients have a hearing threshold of 40–60 dB on the affected side. By comparison, normal function allows us to hear sounds between 0 and 20 dB.


Tissues of both the middle ear and external ear are derived chiefly from the first (mandibular) and second (hyoid) branchial arches. The auricle itself is formed from six “hillocks” of tissue that lie along these arches and can be first seen in the 5-week embryo3537 (Fig. 7.2).




The inner ear first appears at 3 weeks and is derived from tissues of distinctly separate ectodermal origin. Perhaps this explains why it is usually spared the developmental mishap that almost invariably involves the middle ear of microtic patients. Refinements in radiographic technique (polytomography and computed tomography scans) have only occasionally demonstrated dysplasia and hypoplasia of the inner ear.38,39 Inner-ear abnormalities are found in approximately 10% of microtia and atresia cases, but the abnormalities are usually slight (e.g., a dilatation of the lateral semicircular canal). Interestingly, in evaluating approximately 1500 microtic cases over a 25-year period, the author has seen only three patients who were totally deaf. Remarkably, these were unilateral microtias who had no family history of microtia. Because of their normal inner ear, even patients with bilateral microtia usually have serviceable hearing and use bone-conductive hearing aids to overcome the transmission block. If they are referred to an audiologist so that aids can be used as soon as possible, these patients usually develop normal speech. There is no point in waiting several months. Hearing aids should be applied within weeks of birth. Because these bone-conductive aids are cumbersome and label the child as “different” from his or her peers, it is optimal to correct the hearing deficit surgically to eliminate the aids. However, surgically correcting this conductive problem is difficult as the middle ear beneath the closed skin is not normal.


Exploration involves cautiously avoiding the facial nerve while drilling a canal through solid bone. The tympanum must usually be created with tissue grafts from the temporal fascia; the distorted or fused ossicles may be irreparable. As skin grafts do not take well on the drilled bony canal, chronic drainage is a frequent complication and meatal stenosis is common. Finally, unless the surgeon can close the functional difference between the repaired and normal ear to within 15–20 dB (an elusive feat in most surgeons’ hands), binaural hearing will not be achieved. However, in the hands of a competent otologist with a large volume of experience, restoring middle-ear function surgically can be rewarding – even if only one ear is involved.40,41


As many microtia patients do well without middle-ear surgery – 8 out of 9 cases are unilateral and they are “born adjusted” to the monaural condition – most surgeons presently feel that potential gains from middle-ear surgery in unilateral microtia are outweighed by the potential risks and complications of the surgery and that this surgery should be reserved for bilateral cases.


When middle-ear surgery is contemplated, a team approach must be planned with an experienced otologist. In these cases, the auricular construction should precede the middle-ear surgery, as once an attempt is made to “open the ear” the virgin skin is scarred, which compromises a satisfactory auricular construction. On the horizon lie implantable acoustic devices, which may offer a solution for these patients. The bone-anchored hearing aid (BAHA) offers even better hearing than a bone-conductive hearing aid for patients who are not candidates for atresia surgery,42,43 but does require two stages of surgery for optimal implantation of the metal posts in the skull.



Etiology



Incidence


According to an extensive study conducted by Grabb,44 microtia occurs once in every 6000 births. The occurrence is estimated at 1 in 4000 in Japanese, and as high as one in 900–1200 births in Navajo Indians.45



Hereditary factors


In a study conducted by Rogers,46 morphologic, anatomic, and genetic interrelationships were shown to exist between microtia, constricted, and protruding ears. In this thorough investigation, Rogers demonstrated that these deformities are interrelated and can be hereditary.


Preauricular pits and sinuses, and a combination of pits, preauricular appendages, cupping deformity, and deafness, are all hereditarily dominant.1,47 Both dominant and recessive characteristics have been revealed in deafness associated with several auricular abnormalities.48 Ear deformities frequently recur in families of mandibulofacial dysostosis (Treacher–Collins syndrome).49 These are frequently constricted ear deformities, an abnormality that is known to be hereditary.12,5052 Hanhart found a severe form of microtia associated with a cleft or high palate in 10% of family members studied,51 and Tanzer53 found that approximately 25% of his 43 microtia patients had relatives with evidence of the first and second bronchial arch syndrome (craniofacial microsomia); microtia was present in four instances.


In 4.9% of the author’s first 1000 microtia patients, family histories revealed that major auricular deformities occurred within the immediate family, i.e., parents, siblings, aunts, uncles, or grandparents.23 When “distant” relatives were included, the percentage jumped up to 10.3%. In 6% of patients, preauricular skin tags or minor auricular defects were observed in the immediate family. This number also rose to 10.3% when all relatives were included. Immediate family members with normal auricles but underdeveloped jaws or facial nerves were seen in 1.2% of patients.23


In a thorough, intensive survey of 96 families of their 171 microtic patients, Takahashi and Maeda54 ruled out chromosomal aberrations and concluded that inheritance must be multifactorial and that the recurrence risk is 5.7%. In previous studies, others have found multifactorial inheritance between 3 and 8% in first-degree relatives. If a couple has two children with microtia, the risk of recurrence in future offspring is thought to be as high as 15%.



Specific factors


McKenzie and Craig55 and Poswillo56 theorized that the cause of developmental auricular abnormalities is in utero tissue ischemia resulting from either an obliterated stapedial artery or a hemorrhage into the local tissues. This suggests that these deformities arise from a mishap during fetal development rather than from a hereditary source. Interestingly, the author has treated at least 15 microtia patients who have an affirmed identical twin with normal ears.23 Only two sets of the author’s identical twin patients have had concordance for outer-ear deformities; one set were identical mirror-image twins, and the other set both had right-sided microtia. Of interest in the latter set is that each of these male twins with right microtia also had signs and symptoms of pyloric stenosis within 2 days of each other and were operated on at 6 weeks of age (Fig. 7.3).





The occurrence of deafness and occasional microtia resulting from rubella during the first trimester of pregnancy is well known. Also, certain drugs during this critical period may be causative; the author has seen at least 3 cases of microtia which resulted from the mother’s ingestion of the tranquilizer, thalidomide.57,58 Isotretinoin has also been cited as causing ear deformities when ingested during the first trimester.59 In many instances mothers had been unaware of this problem and had used this drug to control acne. Other medications that reportedly cause microtia are clomiphene citrate60 and retinoic acid.61




Associated deformities


As discussed previously, embryological development dictates that the microtic ear is usually accompanied by middle-ear abnormalities. Full-blown, classic microtia is usually associated with canal atresia and ossicular abnormalities. The middle-ear deformity may range from diminished canal caliber and minor ossicular abnormalities to fused, hypoplastic ossicles and failure of mastoid cell pneumatization.


Because the auricle develops from tissues of the mandibular and hyoid branchial arches, it is not surprising that a significant percentage of microtic patients exhibit deficient facial components that originate from these embryological building blocks. These deformities are compiled under the heading of “craniofacial microsomia” (first and second branchial arch syndrome), and an obvious facial asymmetry was noted in 35% of the author’s first 1000 microtia patients.23 The most complete genetic expression of this condition includes defects of the external and middle ear; hypoplasia of the mandible, maxilla, zyogomatic, and temporal bones; macrostomia and lateral facial clefts; and atrophy of facial muscles and parotid gland.44,63,64 Furthermore, Brent found that 15% of his 1000 patients had paresis of the facial nerve.23 Dellon et al. have shown that the palatal muscles are rarely spared in this syndrome.65


Urogenital tract abnormalities are increased in the presence of microtia,66 particularly when the patient is afflicted with other manifestations of the first and second branchial arch syndrome.67 The associated deformities found in the author’s first 1000 microtia patients are compiled in Table 7.1.




Microtia



Clinical characteristics


Microtia varies from the complete absence of auricular tissues (anotia) to a somewhat normal but small ear with an atretic canal. Between these extremes there are an endless variety of vestiges, the most common being a vertically oriented sausage-shaped nubbin (Figs 7.1, 7.5, and 7.6). Microtia is nearly twice as frequent in males as in females, and the right–left–bilateral ratio is roughly 6 : 3 : 1 (Box 7.2).23,29,68






In most instances, the microtic lobule is displaced superiorly to the level of the opposite, normal side, although incomplete ear migration occasionally leaves it in an inferior location. Approximately one-third to one-half the patients exhibit gross characteristics of craniofacial microsomia, although Converse and associates have demonstrated tomographically that skeletal deficiencies exist in all cases.69,70 Whatever the deformity, the author has been impressed with its potential for psychological havoc amongst the entire family, varying from the patient’s emotional insecurity to the parents’ deep-seated guilt feelings.



General considerations


During the initial consultation, it is imperative to describe to the patient and/or his/her family realistically the technical limitations involved in surgically correcting microtia, and to outline alternative methods of managing each individual’s particular deformity. Personally, the author strongly favors autogenous rib cartilage for auricular construction. Although its use necessitates an operation that includes chest surgery, it must be noted that, unlike a reconstruction utilizing alloplastic materials, a successful construction with autogenous tissue is less susceptible to trauma, and therefore eliminates a patient’s overcautious concern during normal activities.


The age at which an auricular construction should begin is governed by both psychological and physical considerations. Since the body image concept usually begins forming around the age of 4 or 5 years,71 it would be ideal to begin construction before the child enters school, and before he/she is psychologically traumatized by his/her peers’ cruel ridicule. However, surgery should be postponed until rib growth provides substantial cartilage to permit a quality framework fabrication.


In the author’s experience with over 1700 microtia patients from age 1 month to 62 years, the patients and/or their families consistently stated that their psychological disturbances rarely began before age 7, and usually became overt from ages 7 to 10. The family is anxious to have the ear repaired as soon as possible, but it is important for the surgeon to wait until it is technically feasible. There usually is enough rib cartilage to serve as the sculpting medium by age 6 and many surgeons begin at that time. If the patient is small for his/her age and/or the opposite, normal ear is large, then it is prudent to postpone the surgery for several years. If not pressured by the family, the best age to begin is about 8 years, when the child is more aware of and concerned with the problem, usually wants it resolved as much as his/her family does, and is helpfully cooperative during the postoperative care phase.


At age 6, the normal ear has grown to within 6 or 7 mm of its full vertical height,72 which permits construction of an ear that will have reasonably constant symmetry with the opposite normal ear. In his follow-up mail survey, Tanzer16,73 found that an ear constructed from autogenous rib cartilage grows at the same rate as the normal ear, with the possible exception of patients operated at 6–7 years of age, where he noted that 50% of these ears lagged several millimeters behind in growth; the roles played in the growth of his patients’ surgically constructed ears by soft tissues and by cartilage have not been determined. In evaluating my own patients29 operated on between ages 5 and 10 with a minimum 5-year follow-up (76 patients), I found that 48.1% of the constructed ears grew at an even pace with the opposite, normal ear; 41.6% grew several millimeters larger; and 10.3% lagged several millimeters behind the normal side. From the limited number of long-term patients in this age group whom I have examined, I found that most constructed ears have grown, and many of these have not only kept up with the little residual growth in the opposite ear, but have slightly overgrown29. I found none to have shrunk, softened, or lost their detail .With all this in mind, I conclude that one should try to match the opposite side during the preoperative planning session, regardless of age. Certainly there is no reason to construct the ear larger, as some investigators have previously thought, and one might even consider making the framework several millimeters smaller in the youngest patients where normal, in situ costal cartilage can be expected to exceed normal auricular cartilage growth.



Author’s method of repair



Staging the auricular construction


The cartilage graft is the “foundation” of an auricular construction and, as in constructing a house, it should be built and well established under ideal conditions before further stages or refinements are undertaken. By implanting the cartilage graft as the first surgical stage, one takes advantage of the optimal elasticity and circulation of an unviolated, virgin skin “pocket.” For these reasons, I prefer to avoid initial lobule transposition or vestige division, since the resulting scars cannot help but inhibit the circulation and restrict the skin’s elasticity. This, in turn, diminishes its ability to accommodate safely a three-dimensional cartilage graft. It seems easier both to judge the earlobe’s placement and to “splice” the lobule correctly into position with reference to a well-established, underlying framework. Although Tanzer transposed the lobule simultaneously with implantation of the cartilage graft during the last three cases of his clinical practice74 and Nagata routinely does this in his technique,32 the author finds that there is far less risk of tissue necrosis and it is far more accurate to transpose the lobule as a secondary procedure7577 (Fig. 7.7). The lobe can be safely transposed and simultaneously the ear can be elevated from the head with skin graft if the earlobe vestige is short, because its small wound closure will not compromise the ear’s anterior circulation23,29 (Fig. 7.8).






During the third stage, the ear is separated from the head and surfaced on its underside with a skin graft to create an auriculocephalic sulcus.


Generally, the fourth stage combines tragus construction, conchal excavation, and simultaneous, contralateral otoplasty, if indicated to achieve optimal frontal symmetry. By combining these procedures, tissues that are normally discarded from an otoplasty can be advantageously employed as free grafts in the tragus construction.



Preoperative consultation


During the initial consultation, surgical expectations and psychological considerations should be discussed with the patient and family, emphasizing reconstruction.


Although costal cartilage can be carved to form a delicate framework, it must be remembered that the volume and projection of the furnished three-dimensional framework are limited by the two-dimensional skin flap under which the framework is placed. Furthermore, because the retroauricular-mastoid skin that covers the framework is somewhat thicker than normal, delicate anterolateral auricular skin, details of a carved framework tend to be blunted. It is important for these limitations to be stressed to the patient and family. In this way, unrealistic expectations as to what can or cannot be produced by surgery can be addressed.


The plastic surgeon’s aim is to achieve accurate representation. That means creating an acceptable facsimile of an ear that is the proper size, in the proper position, and properly oriented to other facial features.


During the consultation, surgical discomforts and inconveniences should be described, including the expected chest pain, duration of dressings, and limited activities for 4–6 weeks. Finally, risks and possible complications of the surgery are discussed thoroughly. These include cartilage graft loss secondary to infection, skin flap necrosis, and hematoma. It should be stressed that with proper precautions, these risks are comparatively less severe than the emotional trauma created by an absent ear. After getting through the initial learning curve of my early years of practice, the ultimate complication rate has been well beneath 1% in the ears that I have constructed from autogenous rib cartilage grafts.



Planning, preparation, and correlation with the correction of other facial deficiencies


image Video1


The result of a total ear reconstruction depends not only on a surgeon’s meticulous surgical technique, but, even more importantly, on careful preoperative planning. It is essential to practice carving techniques on a volume of human cadaver cartilage prior to any live-patient application. Alternatively, ear framework carving can be demonstrated on large slices of potatoes; carrots serve well to practice forming a thin, flexible helix. An acrylic or plaster replica of a normal ear serves as an excellent model for practice carvings.


During the patient’s second office consultation, preoperative study photographs are obtained, and an X-ray film or thin plastic film pattern is traced from the opposite, normal ear. This pattern is reversed, and a framework pattern is designed for the new ear. After sterilization, these patterns serve as guidelines for framework fabrication at the time of surgery.


The reconstructed ear’s location is predetermined by first noting the topographical relationship of the opposite, normal ear with facial features and then duplicating its position at the proposed reconstruction site. First, the vestige’s height is compared from the front view with that of the opposite, normal ear. From the side, it should be noted that the ear’s axis is roughly parallel to the nasal profile34,78 (Fig. 7.9). Finally, one notes and records the distance between the lateral canthus and the normal ear’s helical root. Typically, this distance is about 65–67 mm in a 6-year-old child.



The ear’s location is determined by first taping the reversed film pattern to the proposed construction site, and then adjusting its position until it is level to and symmetrical with the opposite normal ear. The pattern is traced on the head, noting the ear’s axial relation to the nose, its distance from the lateral canthus, and its lobule’s position, which is usually superiorly displaced. The ear’s new position is straightforward and easy to plan in a pure microtia, but much more difficult when severe hemifacial microsomia exists. Not only are the heights of the facial halves asymmetrical, but the anteroposterior dimensions of the affected side are foreshortened as well. In these patients, the new ear’s height is best determined by lining it up with the normal ear’s upper pole – its distance from the lateral canthus is somewhat arbitrary.


In pure microtia, the vestige-to-canthus distance mirrors the helical root-to-canthus distance of the opposite, normal side. However, in severe hemifacial microsomia patients, the vestige is much closer to the eye. If the new ear’s anterior margin is placed at the vestige site, then the ear appears too close to the eye; if the measured distance of the normal side is used as a guide, then the ear looks too far back on the head. In these patients, I find it best to compromise by selecting a point halfway between these two positions.


When both auricular construction and bony repairs are planned, then careful, integrated timing is essential. Most often the family pushes for the ear repair to begin first, which helpfully assures the auricular surgeon virginal, unscarred skin. The craniomaxillofacial surgeon argues that by going first s/he will correct the facial symmetry, thus making ear placement easier.79 I find this unnecessary when the guidelines described above are followed.


If the bony work is done first, it is imperative that scars are peripheral to the proposed auricular site. When a coronal incision is used to approach the upper face or to harvest cranial bone grafts, special care must be taken that the scar does not precariously lie over the future region of the upper helix.



First stage of reconstruction


Almost invariably, the author’s first-stage “foundation” in correcting microtia is fabricating and inserting the cartilaginous ear framework. As discussed previously, scars can be a significant handicap; the author rarely employs a preliminary procedure.



Obtaining the rib cartilage


Rib cartilages are obtained en bloc from the side contralateral to the ear being constructed, so as to utilize natural rib configuration. The rib cartilages are removed through a horizontal or slightly oblique incision which is made just above the costal margin. Following division of the external oblique and the rectus muscles, the film pattern is placed on the exposed cartilages to determine the necessary extent of rib resection.


The helical rim is fashioned separately with cartilage from the first free-floating rib (Fig. 7.10). Excision of this cartilage facilitates access to the synchondrotic region of ribs 6 and 7, which supplies a sufficient block to carve the framework body. Extraperichondrial dissection is preferable in obtaining an unmarred specimen. I find that well-documented chest deformities80,81 can be significantly decreased by preserving even a minimal rim of the upper margin of the sixth rib cartilage where the basic shape of the ear is obtained (Fig. 7.10). This precautionary measure retains a tether to the sternum so that the rib does not flare outward to distort the chest as the child grows. If the synchondrotic region seems inadequate in width, one can compensate for framework width by bowing the helix away from the framework body (the “expansile” design82), rather than violating the sixth-rib margin and sacrificing chest wall integrity.



In cases where the delicate pleura is entered during this dissection, there is no great reason for concern, as a leak in the lung has not been produced. However, when a pleural tear is discovered, a rubber catheter is inserted well into the chest through the pleural opening; then the chest wound is closed in layers by the assistant, while the surgeon fabricates the framework, thus conserving operative time. When skin closure is complete, the catheter is attached to suction, the lung is expanded with positive pressure by the anesthesiologist, and the surgeon rapidly withdraws the catheter. As a final precaution, the patient receives a portable upright chest X-ray in the operating room.




Framework modifications in older patients


Adult rib cartilages are often fused into a solid block, which invites one to sculpt the ear framework in one piece – not unlike doing a wood carving (Fig. 7.11). In my experience, this is advantageous because adult cartilage is often calcified; it is difficult, if not impossible, to create a separate helix that will bend without breaking. If a one-piece carving produces insufficient helical projection, the helix can be detached and slid up the framework body to augment the protrusion of the rim. This improved contour is maintained by reattaching the helix to the framework with several permanent sutures (Fig. 7.12).






Framework implantation


A cutaneous pocket is created with meticulous technique so as to provide an adequate recipient vascular covering for the framework. Through a small incision along the backside of the auricular vestige, a thin flap is raised by sharp dissection, taking care to preserve the subdermal vascular plexus. So as to evaluate the flap’s vascular status and to assure accurate hemostasis, epinephrine-containing solutions are avoided. With great care, the skin is dissected from the gnarled, native cartilage remnant which then is excised and discarded. Finally, the pocket is completed by dissecting a centimeter or two peripherally to the projected framework markings (Fig. 7.1).


Insertion of the framework into the cutaneous pocket takes up the valuable skin slack which was created when the native cartilage remnant was removed. The framework displaces this skin centrifugally in an advantageous posterosuperior direction so as to displace the hairline just behind the rim. This principle of anterior incision and centrifugal skin relaxation, introduced by Tanzer,15 not only permits advantageous use of the hairless skin cover, but also preserves circulation by avoiding incisions and scars along the helical border.


Although Tanzer initially suggested the use of bolster sutures to coapt the skin flap to underlying framework,15,84 the author finds it far safer to do this with suction, which simultaneously prevents fluid collection and minimizes the risk of flap necrosis along the helical margin.


To attain skin coaptation via suction, silicone catheters are used with the needles inserted into rubber-topped vacuum tubes, the tubes being retained on a rack to observe changes in quantity and quality of drainage. Although a dressing is applied which accurately conforms to the convolutions of the newly created auricle, firm pressure is dangerous and unnecessary, and must be avoided. Hemostasis and skin coaptation are provided by the suction drain.17,29,75,77



Immediate postoperative care and management of complications


I pack the new ear’s convolutions with Vaseline gauze and apply a bulky, noncompressive dressing. Since the vacuum system provides both skin coaptation and hemostasis, pressure is unnecessary and contraindicated. The first day, the tubes are changed by the ward nurses every few hours, then every 4–6 hours thereafter or when a tube is one-third full. I now discharge the patient the day after surgery and teach the parent to change the tubes (three times a day). The drains remain in place for several more days until the testtubes contain only drops of serosanguineous drainage. I routinely remove them at 5 days. By then the overlying skin is adherent to the framework and hematoma is no longer a threat; to leave them in longer seems unnecessary, particularly since the catheters could possibly serve as wicks to facilitate bacterial transport along the tubes.


Postoperatively, the ear is checked and the protective head dressing is changed several times, and discarded after about 11–12 days.


Attentive postoperative management is imperative for a successful ear reconstruction which remains unhampered by disastrous complications. The newly constructed auricle is scrutinized frequently and carefully for signs of infection or vascular compromise.


Usually, early infection manifests itself neither by auricular pain nor fever, but through local erythema, edema, subtle fluctuance, drainage, or a combination of the above. Hence, frequent observations and the immediate institution of aggressive therapy can deter an overwhelming infection.


Immediately upon suspecting an infection, an irrigation drain is introduced below the flap, and continuous antibiotic drip irrigation is begun. Appropriate adjustments are made in both the antibiotic drip irrigation and in the systemic therapy when sensitivities are available from the initial culture. Cronin17 has salvaged Silastic-frame reconstructions impressively by this technique, and I had success in managing the rare infection in cartilage graft reconstructions when I was using bolster sutures during my first 15–20 cases. The problem of infections basically disappeared when I switched over to the suction drain system and I have not experienced one in an autogenous cartilage framework for nearly 30 years.


Skin flap necrosis results from excess tension in an inadequate-sized pocket, tight bolster sutures, or damage to the subdermal vascularity during the flap dissection. This complication is best avoided by meticulous technique; however, once skin necrosis becomes evident, appropriate steps must be taken without delay.


Although at times a small local flap may be required to cover exposed cartilage, small localized ulcerations may heal with good local wound care. This consists of continually keeping the wound covered with antibiotic ointment to prevent cartilage desiccation and using restraints to prevent the patient from lying on his/her ear during sleep.


However, major skin flap necrosis merits a more aggressive approach if the framework is to be salvaged. The necrotic skin is excised early, and the framework is covered by transposing a local skin flap or by using a small fascial flap and skin graft.




Other stages of auricular construction


Major stages in auricular construction subsequent to the initial framework implantation are lobule rotation, separating the ear from the head with a skin graft, deepening of the concha, and formation of a tragus. These stages can be planned independently or in various combinations, depending on which best achieves the desired end result.



Rotation of the lobule


The author prefers to perform earlobe transposition as a secondary procedure, as it seems easier both to judge placement of the earlobe and to “splice” the lobule correctly into position with reference to a well-established, underlying framework. Although the author has occasionally transposed the lobule simultaneously with implantation of the cartilage graft, he has found it safer and far more accurate to transpose the lobule as a secondary procedure.


The “rotation” or repositioning of this normal but displaced structure is accomplished essentially by Z-plasty transposition of a narrow, inferiorly based triangular flap (Fig. 7.13).



Nagata32 and Firmin85 transpose the earlobe and utilize skin from the lobule’s posterior surface to line the framework’s tragal strut during the first-stage surgery. This does produce an excellent tragal appearance, but the price paid is greater risk of skin necrosis, and earlobes which are at times compromised in appearance and often unable to accommodate earrings. This latter problem is no small issue for my young female patients, who often submit to surgery with eventual earlobe piercing as their highest priority.23


If the lobe vestige is short so that a substantial skin bridge can be preserved above it during its transposition, then the earlobe can safely be moved while simultaneously separating the auricle from the head to create the auriculocephalic sulcus23,29 and preserve sufficient posterior earlobe skin to permit the use of earrings (Fig. 7.8).



Tragal construction and conchal definition


One can form the tragus, excavate the concha, and mimic a canal in a single operation. This is accomplished by placing a thin elliptical-shaped chondrocutaneous composite graft beneath a J-shaped incision in the conchal region75,77 (Fig. 7.14). The main limb of the “J” is placed at the proposed posterior tragal margin; the crook of the “J” represents the intertragal notch. Extraneous soft tissues are excised beneath this tragal flap to deepen the concha; this excavated region looks quite like a meatus when the newly constructed tragus casts a shadow upon it.



It is advantageous to harvest the composite graft from the normal ear’s anterolateral conchal surface due to its ideal shape and the paucity of subcutaneous tissue between the delicate anterolateral skin and adjacent cartilage. This technique is particularly ideal when a prominent concha exists in the normal donor ear, since closure of the donor site facilitates an otoplasty, which often is needed to gain frontal symmetry.


I also use an alternative method of creating the tragus as an integral strut of the original framework during its initial fabrication. I achieve this with a small piece of rib cartilage which is first fastened to the frame so as to create the antitragal eminence. The strut is thinned on one side, then curved around and affixed by its distal tip with a clear nylon suture which stretches across to the frame’s crus helix. The result is a delicate tragus which flows naturally from the main framework through an arched intertragal notch (Fig. 7.15). This method of tragus construction is particularly advantageous in bilateral microtia where there is no source for special composite tissue grafts. Nagata also creates the tragus with an extra cartilage piece attached to his main framework (Fig. 7.16), and lines it with skin from the earlobe vestige during the first stage of surgery.




Another option for tragus construction in bilateral microtia is the modified Kirkham method, which consists of an anteriorly based conchal flap doubled on itself.11



Detaching the posterior auricular region


Auricular separation with skin grafting is done solely to eliminate the cryptotic appearance by defining the ear through creating a sulcus. This procedure will not project a framework which has been carved with insufficient depth.


The posterior auricular margin is defined by separating the ear from the head and covering its undersurface with a skin graft. In the past, I used a thick split graft but now strictly use full-thickness skin grafts. This stage of surgery should not be attempted until the edema has markedly subsided and the auricular details have become well defined. This surgery is initiated by making an incision several millimeters behind the rim, taking care to preserve a protective connective tissue layer on the cartilage framework. The retroauricular skin is then advanced into the newly created sulcus so that the only graft requirement is on the ear’s undersurface. I harvest a full-thickness skin graft from the lower abdomen or groin crease and suture it to the wound with the sutures left long; these are tied over a bolster to tamponade the graft to the recipient bed (Fig. 7.17).




Greater projection of the auricle can be achieved by placing a wedge of rib cartilage behind the elevated ear, but this must be covered with a tissue flap in order for the skin graft to take over the cartilage. Nagata32 accomplishes this with an axial flap of temporoparietal fascia (Fig. 7.18). However, use of that fascial flap is not without a certain morbidity, and I feel that this fascia should be reserved for significant traumatic and secondary reconstruction cases where there is no other option for their solution.29 Like Firmin85 and Weerda,86 I prefer to cover the cartilage wedge with a turnover “book flap” of occipitalis fascia from behind the ear23 (Fig. 7.8). When this cartilage-wedging technique is used, there is no need to subject the patient to a second uncomfortable chest operation by harvesting rib cartilage anew, as does Nagata.87 Instead, an extra piece of cartilage can be banked underneath the chest incision during the initial first-stage procedure. When the wedge is needed during the elevation procedure, it can be easily retrieved by incising through the original chest scar. Alternatively, I have also banked this cartilage wedge underneath the scalp, just posterior to the main pocket where the completed ear framework is placed23 (Fig. 7.8A). This site is particularly advantageous in that the nearby banked cartilage can more conveniently be retrieved when later lifting the new ear from the head; furthermore, this scalp site seemingly provides better nourishment for the banked cartilage than does the subcutaneous chest region.

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Feb 21, 2016 | Posted by in General Surgery | Comments Off on Reconstruction of the ear
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