Microtia repair with autogenous rib cartilage grafts

MICROTIA REPAIR WITH AUTOGENOUS RIB CARTILAGE GRAFTS BURTON BRENT, MD

Over the past 2 decades, the author has developed techniques to implement autogenous tissues in the repair of microtia in patients of all ages. Cartilage grafts, unlike bone grafts, do not require functional stress to ensure their long-term survival. Therefore, the constructed ear in the young patient probably can be expected to grow at least as much as the normal ear. Surgical construction of the auricle with autogenous tissues is a unique marrying of science and art. Although the surgeon's facility with both sculpture and design is imperative, the surgical result will be equally influenced by his/her adherences to sound principles of plastic surgery and tissue transfer. KEY WORDS: auricular reconstruction; autogenous cartilage tissues; ear reconstruction; microtia

This report is meant to present a sound approach to total auricular construction by methods that have evolved through 2 decades of personal experience with 850 cases.

cone ear frameworks lost to even minor trauma up to 12 years after implantation. On the other hand, once safely passing the 10th postoperative day, I have never lost an autogenous ear framework. To date, more than 40 of my reconstructed ears have survived major trauma.

INITIATING THE SURGERY The age at which one begins surgery is governed both by physical and psychological considerations. It is best to initiate the repair before the child is traumatized by cruel teasing, but the surgeon must not be pressured to begin until rib growth provides substantial cartilage for framework fabrication. 1 In my experience, these children become aware that their ears are different between ages 3 and 4 years, but teasing with psychological overtones does not become manifest until ages 7 to 10. Generally, there is substantial cartilage for the repair by age 6, by which time the child is aware of the problem, usually wants it resolved, and is surprisingly cooperative regarding the surgery. If the opposite, normal ear is large and the child is small, one may have to postpone the surgery for several years. On the other hand, a large child with a small normal ear may permit one to begin by age 51//2. In my experience, beginning surgery earlier than this merely invites technical handicaps and poor patient cooperation.

SELECTING THE METHOD In contrast to homologous cartilage, which absorbs, 2 and silicone frameworks, which often fail, 3 autogenous cartilage produces favorable results, experiences few complications, and withstands trauma. 4'5'6 I have seen siliAddress reprint requests to Burt Brent, MD, Suite 300, 2995 Woodside Rd, Woodside, CA 94062. Copyright © 1994 by W. B. Saunders Company 1071-094/94/0102-0002505.00/0

PREOPERATIVE PLANNING The successful grafting of a well-sculpted cartilage framework is the foundation for a sound ear repair. By accomplishing this as the first surgical stage, one takes advantage of the optimal circulation and elasticity of inviolated virgin skin. With this in mind, I avoid initial repositioning of vestige remnants, because resulting scars can inhibit circulation and restrict the skin's elasticity and ability to accommodate a three-dimensional framework. 7 Secondary procedures such as lobule rotation, tragus construction, and sulcus grafting take place on sound healing of the "foundation." Shortcuts with so-called "one-stage repairs ''s are risky and produce ears that inevitably require further detailing to achieve a quality result. 9 I initiate the planning by first tracing a film pattern from the opposite normal ear, which is reversed and used to plan the new framework. I then make a n e w pattern several millimeters smaller in all dimensions to allow for the extra thickness that occurs when the cartilaginous framework is inserted under the skin. The framework's inferior pole is greatly reduced to accommodate the earlobe on its transposition. If the patient has no usable earlobe tissue, I carve the framework's lower end to resemble an earlobe. This is further defined w h e n I separate the ear from the head with a skin graft. I predetermine the ear's location in the office 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. I trace the pattern on the head, noting the ear's axial

Operative Techniques in Plastic and Reconstructive Surgery, Vol 1, No 2 (August), 1994: pp 69-76

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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 anterior-posterior dimensions of the affected side are foreshortened as well. In these patients, one best plans the new ear's height 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 one places the new ear's anterior margin at the vestige site, then the ear appears too close to the eye; if one uses the measured distance of the normal side 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 craniomaxfllofacial surgeon argues that by going first he will correct the facial symmetry thus making ear placement easierJ ° I find this unnecessary w h e n the above described guidelines are followed. If the bony work is performed 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.

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Use entire floating cartilage for helix Fig 1. Rib cartilage harvest for ear framework fabrication. Film pattern is used as reference in harvesting synchondrotic block of cartilage. Note that upper border of sixth cartilage is preserved; this will help to prevent subsequent chest deformity as child grows. The entire "floating cartilage" will be used to create the helix.

ear repair, I do not use antibiotics, except w h e n elevating and grafting the ear of an adolescent patient with intractable acne.

Framework Fabrication THE FIRST SURGICAL STAGE Harvesting the Rib Cartilage I remove the rib cartilages through a slightly oblique incision made just above the costal margin. Once the muscle has been divided, I use the film patterns to determine which cartilages will serve best for the framework (Fig 1). To take advantage of the natural rib configuration, one harvests the cartilage from the side contralateral to the ear being constructed. 7 The first free-floating cartilage tapers favorably to form the helix; the synchondrotic region of ribs 6 and 7 provides an ample cartilage block to form the framework body. To conserve anesthetic time, m y assistant closes the chest w o u n d while I fabricate the framework. Using this approach, the entire operation (rib harvest, framework fabrication, and its insertion beneath the auricular skin) routinely takes less than 3 hours. When grafting cartilage, I use intraoperative antibiotics as a prophylactic measure, and continue their use for several days post procedure. In subsequent stages of

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The basic ear silhouette is carved from the synchondrotic cartilage block. It is necessary to thin little, if any, of the basic form for a small child's framework, but cartilage thinning is essential for adult frameworks. When thinning is necessary, it is wise to preserve perichondrium on the lateral, outer aspect of the framework (notably the antihelical complex) to facilitate its adherence to and subsequent nourishment from surrounding tissues. When creating the helix, the floating rib cartilage is thinned on its outer, convex surface to cause deliberate warping 1 in a favorable direction (Fig 2). 11 This allows one to produce the acute flexion necessary to create a helix, which one then fastens to the framework body with horizontal mattress sutures. For this purpose, I now use 4-0 clear nylon and bury the knots on the framework's undersurface. I stabilize the helix by affixing it to the main cartilage block (Fig 3). Through years of observing the healing process, I continue to evolve and modify the framework to achieve optimal helical stability and projection. Presently, I prefer to attach the helical cartilage anterior to the inferior crus first. This creates maximum framework width while maintaining the normal, low projection of the crus helix.

BURTON BRENT

Fig 2. Carving the helix from the "floating" rib cartilage. To produce the acute flexion necessary to create the helix, the cartilage is deliberately warped in a favorable direction by thinning it on its outer, convex surface.

Stability is next achieved when I wrap the helix around the superior pole of the helix. Finally, I maximize projection where it is most needed by affixing the terminal helix on top of the main cartilage block along the flamework's posterior border (Fig 3).

The Cutaneous "Pocket" and Skin Coaption A cutaneous pocket is created with meticulous technique to provide an adequate recipient vascular covering for the framework. Because nearly 2 hours lapse during the rib harvest and framework fabrication, I minimize contami-

nation risk by prepping and scrubbing the auricular region just before beginning the cutaneous dissection. Using the template and preoperatively determined measurements, I mark the ear's position and make a small preauricular incision. On excising unusable vestigual cartilage, one then develops a thin skin "pocket," taking great care not to damage the subdermal vascular plexus. To recruit sufficient tension-flee skin coverage, the dissection is carried well beyond the marked auricular outline (Fig 4). Following any necessary adjustments either to the framework height or to the pocket adequacy, I insert two small silicone drains beneath and behind the framework

Fig 3. Ear framework fabrication with sculpted rib cartilage. The thinned helix is affixed to the main sculptural block with horizontal mattress sutures of 4-0 clear nylon; the knots are placed on the framework's undersurface.

AUTOGENOUS RIB CARTILAGE GRAFTS

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Fig 4. The cutaneous "pocket." The vestigial native cartilage is excised and then a skin pocket is created. To provide tension-free accommodation of the framework, the dissection is performed well beyond the proposed auricular position. Using two silicone catheters, the skin is coapted to the framework by means of vacuum tube suction.

and then into vacuum test tubes (Fig 4). This creates a continuous suction that not only coapts the nourishing skin flap to the carved cartilage but also prevents possible disastrous hematomata.

Dressings and Postoperative Care ! pack the new ear's convolutions with Vaseline gauze and apply a bulky, noncompressive dressing. Because the vacuum system provides both skin coaption and hemostasis, pressure is unnecessary and contraindicated. The first day, the tubes are changed by the ward nurses every few hours and then every 4 to 6 hours thereafter or w h e n a tube is one-third full. Although the patient leaves the hospital in several days, the drains remain in place for another 2 to 3 days until the test tubes contain only drops of serosanguinous drainage. Postoperatively, the ear is checked and the protective head dressing is changed several times and removed after about 12 days. At that time, I permit the patient to resume school but restrict running and sports for another 4 to 5 weeks while the chest w o u n d heals.

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OTHER STAGES OF THE AURICULAR CONSTRUCTION To allow for proper healing, a minimum of 3 months is allowed between the staged surgeries. This extra time allows for the swelling to subside, for circulation to improve, and for the tissues to settle down.

Lobule Transposition I prefer to perform earlobe transposition as a secondary procedure because it is easier to "splice" the lobular remnant into position and to wrap it around the bottom of a well-established, previously constructed auricle. Although it is possible to transpose the lobule while simultaneously placing the framework, :3 1 find it safer and far more accurate to transpose the lobule secondarily. :4 This can be accomplished on an outpatient basis several months after the cartilage graft. Using the lobular remnant can be the most challenging and creative part of the reparative process. Recently, I have found that lifting the framework's tip and filleting the lobule to receive it will enhance the inset (Figs 5 and

BURTON BRENT

Fig 5. Stage 2, earlobe transposition. By incising around It, the Iobule is mobilized as an inferiorly based flap; an incision is outlined at the proposed superior Inset margin. The skin overlying the lower ear region is loosened so that it can be siid under the elevated framework's tip to surface the 'fftoor" beneath it; the Iobule is filleted so that It can be wrapped around the carUlaginous framework tip in a twolayered closure (see Fig 6).

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Fig 6. Earlobe tmnsposition, continued. The tip of the cartilaginous framework is elevated from its soft-tissue bed, and the illleted earlobe is wrapped around it. in this repair, note that the skin that overlaid the cartilaginous tip is now shifted beneath it to surface the raw bed vacated by the framework.

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6) and facilitate the next procedure w h e n the ear is separated from the head with a skin graft.

Detaching Auricle With Skin Graft I separate the ear from the head with a skin graft and create a sulcus solely to define the ear's posterosuperior margin. This improves the ear's appearance by eliminating a cryptotic appearance. 15 This procedure does not project a framework that has been carved with insufficient depth. I achieve frontal symmetry later during tragus construction w h e n the contralateral ear can be set back while harvesting grafts for the tragus. Beginning with an incision made several millimeters peripheral to its margin, I lift the surgically constructed auricle from its bed, taking care to preserve connective tissue both on its cartilaginous undersurface and on the bony floor below (Fig 7). I then undermine and advance the retroauricular scalp toward the newly created sulcus and affix it to the fascia and periosteum with heavy sutures (Fig 7). This not only decreases the size graft one needs, but permits one to advance the hairline so that the graft is invisible from the lateral profile. Because this graft is applied to the back of the ear and color match is no issue, I prefer to harvest it as medium-

thick split skin from the side of the hip, hidden beneath the patient's bathing suit region.

Tragus Construction In a single procedure, [ form the tragus, excavate the concha, and mimic a canal by inserting a special, arched composite graft through a J-shaped incision in the conchal region. 16 The main limb of the "J" is placed at the proposed posterior tragal margin; the crook of the "J" represents the intertragal notch (Fig 8). I excise extraneous soft tissues beneath the tragal flap to deepen the conchal floor. This excavated region looks quite like a meatus w h e n the newly constructed tragus casts a shadow on it. To create a realistic tragus with the best curvature, I harvest the composite graft from the anterolateral conchal surface of the normal ear. This technique is particularly ideal w h e n a prominent concha exists, because the donor site closure facilitates an otoplasty, which often is needed to attain frontal symmetry. If I find the concha not prominent and/or the projection of both ears equal before tragus construction, then I graft the donor concha. This is easily accomplished by harvesting a small ellipse of skin from just in front of the retroauricular hairline.

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Fig 7. Stage 3, separating the surgically constructed ear from the head with skin graft. An incision is made several millimeters peripheral to the surgically constructed ear, and the auricle is sharply elevated from its fasclal bed. The scalp is advanced to the newly created sulcus both to decrease graft requirements and to hide the graft by limiting its placement mostly to the ear's undersurface. Long silk sutures are tied over a bolus dressing.

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BURTON BRENT

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Fig 8. Stage 4, tragus construction and conchal excavation. Harvested from the opposite, normal ear's conchal region, a chondrocutaneous composite graft is placed under a thin J-shaped flap to create the tragus. Before surfacing the floor of the tragal region with a full-thickness skin graft (harvested from behind the opposite earlobe), extraneous soft tissues are excised to deepen the region.

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Combining Surgical Stages I rarely perform more than one surgical stage at one time. Unlike wood carving or clay sculpting, surgically sculpting tissues depends on good circulation. Therefore, I feel safe in combining upper-ear resurfacing with either lobule transposition or tragus construction, but unsafe in combining lifting an ear with constructing a tragus or lifting an ear with any major anterior resurfacing procedure. The former perilously surrounds the auricle with incisions and undermining, whereas the latter dangerously "skeletonizes" the ear. I also feel safe in simultaneously elevating the ear and transposing the lobule if the original earlobe vestige is short, because its small wound closure will not compromise the ear's anterior circulation.

BILATERAL MICROTIA For optimal function and aesthetics in bilateral microtia, one must plan to integrate surgical procedures so that one does not compromise the other. In these cases, the

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auricular construction should precede the middle ear surgery because once an attempt is made to "open" the ear, chances of obtaining a satisfactory auricular repair are severely compromised because the invaluable virgin skin has been scarred. When middle-ear surgery is contemplated, I modify the framework by sculpting a wider concha to accommodate the future surgical canal. In bilateral microtia, I cartilage graft each side several months apart, because each hemithorax contains sufficient cartilage for only one good ear framework. Simultaneous bilateral reconstruction necessitates bilateral chest wounds with attendant splinting and respiratory distress. Furthermore, the first auricular repair might be jeopardized on turning the head to do the second side. For these reasons, I prefer to do the first stage of each ear on separate occasions. Several months after the second cartilage graft, both earlobes are transposed during a single procedure. Once this stage is healed, one can either separate the ears from the head with skin grafting, do the tragus constructions (Kirkham method), 17 or pursue the middle-ear surgery.

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To e n s u r e t h a t t h e g a i n s of m i d d l e - e a r s u r g e r y o u t w e i g h t h e risks a n d c o m p l i c a t i o n s of t h e p r o c e d u r e itself, I r e s e r v e this s u r g e r y for bilateral microtia a n d selected unilateral cases in w h i c h t h e r e is h i g h p a t i e n t m o t i v a t i o n a n d favorable radiological e v i d e n c e of m i d d l e - e a r develo p m e n t . T h e n it m u s t be t h o u g h t f u l l y p l a n n e d in a " t e a m a p p r o a c h ''18"19 w i t h a n o t o l o g i s t w h o is c o m p e t e n t a n d well e x p e r i e n c e d in atresia s u r g e r y .

CONCLUSIONS T h r o u g h t e c h n i q u e s t h a t h a v e e v o l v e d o v e r 2 d e c a d e s of p e r s o n a l e x p e r i e n c e w i t h a large v o l u m e of patients, aut o g e n o u s t i s s u e s h a v e s u c c e s s f u l l y r e p a i r e d microtia in p a t i e n t s of all a g e s . I n t h e y o u n g p a t i e n t , t h e c o n s t r u c t e d ear p r o b a b l y c a n be e x p e c t e d to g r o w at least as m u c h as t h e n o r m a l ear. I n c o n t r a s t to b o n e grafts, 2° cartilage grafts d o n o t r e q u i r e f u n c t i o n a l stress to e n s u r e their long-term survival. As experience has been g a i n e d , c o m p l i c a t i o n s h a v e b e c o m e rare. W h e n c o n f r o n t e d w i t h a n a d o l e s c e n t microtia p a t i e n t w h o feels t h a t h e is n o t " s e v e r e l y " affected b y his d e f o r m i t y , o n e m u s t listen a n d be selective a n d c a u t i o u s l y stress the limitations of the s u r g e r y e v e n m o r e t h a n usual.

REFERENCES 1. Tanzer RC: Total reconstruction of the external ear. Plast Reconstr Surg 23:1, 1959 2. Steffenson WH: Comments on reconstruction of the external ear. Plast Reconstr Surg 16:194, 1955 3. Tanzer RC: Discussion of silastic framework complications, in Tanzer RC, Edgerton MT (eds): Symposium on Reconstruction of the Auricle. St Louis, MO, Mosby, 1974, pp 87-88

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4. Tanzer RC: An analysis of ear reconstruction. Plast Reconstr Surg 31:16, 1963 5. Brent B: Auricular repair with autogenous rib cartilage grafts: Two decades of experience with 600 cases. Plast Reconstr Surg 90:355, 1992 6. Brent B: The correction of microtia with autogenous cartilage grafts: I. The classic deformity. Plast Reconstr Surg 66:1, 1980 7. Brent B: The correction of microtia with autogenous cartilage grafts. II. Atypical and complex deformities. Plast Reconstr Surg 66:13, 1980 8. Song Y, Song Y: An improved one-stage total ear reconstruction procedure. Plast Reconstr Surg 71:615, 1983 9. Tanzer RC: Microtia--A long-term follow-up of 44 reconstructed auricles. Plast Reconstr Surg 61:161, 1978 10. Lauritzen C, Munro IR, Ross RB: Classification and treatment of hemifacial microsomia. Scand J Plast Reconstr Surg 19:33, 1985 11. Gibson T, Davis WB: The distortion of autogenous cartilage grafts: Its cause and prevention. Br J Plast Surg 10:257, 1957 12. Brent B: Ear reconstruction with an expansile framework of autogenous rib cartilage. Plast Reconstr Surg 53:619, 1974 13. Tanzer RC: Total reconstruction of the auricle. The evolution of a plan of treatment. Plast Reconstr Surg 47:523, 1971 14. Brent B: The correction of microtia with autogenous cartilage grafts. I. The classic deformity. Plast Reconstr Surg 66:1, 1980 15. Brent B: Total auricular construction with sculpted costal cartilage, in Brent B (ed): The Artistry of Reconstructive Surgery. St Louis, MO, Mosby, 1974, pp 113-127 16. Brent B: A personal approach to total auricular construction, in Brent B (ed): Aesthetic Aspects of Reconstructive Surgery. Clin Plast Surg 8:211, 1981 17. Kirkham HLD: The use of preserved cartilage in ear reconstruction. Ann Surg 111:896, 1940 18. Broadbent TR, Woolf RM: Bilateral microtia: A team approach to the middle ear, in Tanzer RC, Edgerton MT (eds): Symposium on Reconstruction of the Auricle. St. Louis, MO, Mosby, 1974, pp 168-173 19. Brent B: Auricular repair with autogenous rib cartilage grafts: Two decades of experience with 600 cases. Plast Reconstr Surg 90:355, 1992 20. Knize DM: The influence of periosteum and calcitonin on onlay bone graft survival. Plast Reconstr Surg 53:190, 1974

BURTON BRENT