CHAPTER 2 Stage I: Reproduction of the Missing Contours



10.1055/b-0037-144950

CHAPTER 2 Stage I: Reproduction of the Missing Contours


The first stage of ear reconstruction consists of harvesting, sculpting, and placing the cartilage under the skin. The principles are similar for both microtia and trauma. Particular problems encountered in each situation will be discussed in their subsequent chapters.



PREOPERATIVE CONSULTATION


The preparation for the operation begins during the first consultation by informing the patient of all of the information pertaining to the procedure and the time frame for recovery.




  • Routinely, preoperative CT scans of the head and thoracic region are ordered to evaluate possible ossification of the costal cartilage.



  • The procedure is generally very well tolerated.



  • The auricular area is not painful, but pain from the thorax may be present for 24 hours. This is managed by intercostal nerve blocks during surgery and oral analgesia.



  • Patients will be hospitalized for 3 or 4 days after the procedure, and recovery usually takes 2 weeks.



Photography

Fig. 2-1

Routine preoperative pictures are taken. We used to take 1:1 black and white pictures and obtain measurements from the prints. We found this particularly useful in patients with asymmetry, such as those with hemifacial microsomia. In trauma patients, we rely on the external auditory meatus as a fixed landmark around which we can position the ear. All landmarks from the normal side are drawn on the affected side to ensure correct placement of the framework (see Fig. 2-17 for a description of the white lines).



Computed Tomography and Three-Dimensional Modeling


A preoperative CT scan is very useful not only to analyze the auditory apparatus but also to appreciate the costal cartilage potential. From this CT scan, we routinely obtain a three-dimensional-printed model of the normal ear, which has been digitally inverted to provide an accurate model for the affected side. With the appropriate protocol, this model can be produced within 3 hours of the CT scan.

Fig. 2-2

In addition to a three-dimensional model, a specific reformatting protocol (three-dimensional maximum intensity projection) for thoracic CT scans is used to evaluate the amount of cartilage in young patients and the orientation of the costal segments (which may dictate the ideal position for the skin incision). In adults, the ossification status is also checked. Ossification is not a contraindication, but identifying it preoperatively is helpful to plan for a much longer time for sculpture and to ensure a drill and fine burr tips are available.


We have found that a patient′s ossification status cannot be predicted based on age, and that the correlation is low.

Fig. 2-3 This scan of a 10-year-old patient shows no ossification (A). In this 55-year-old woman, the red color is not homogeneous. It is an adult cartilage without ossification but with a yellow color and firm consistency, ideal for carving (B). This 45-year-old man presenting with an unoperated right microtia has some ossification, but harvesting and carving the sixth through eighth costal cartilages is possible (C). The scan of this 13-year-old patient is surprising. It reveals significant ossification, facilitating planning for a longer operative time and the use of drills (D). (See Quality of the Cartilage later in the chapter.)


Doppler Mapping


It may be useful to perform Doppler mapping of the superficial temporal artery during the consultation. We find this necessary in secondary and traumatic cases to determine whether the superficial temporal artery has been severed and whether a temporal fascial flap is a viable option.



Consultation With an Ear, Nose, and Throat Specialist


In all cases of primary infection we have encountered, a canal was present. Consequently, for all patients with an auditory canal, we request a preoperative ENT consultation to include canal cleaning under the microscope and implementation of antibiotic drops 1 week before surgery. We have had no patients with primary infections since initiating this protocol.



CARTILAGE SELECTION


Although the ribs to be harvested are selected during surgery, it is essential to understand all the factors influencing this selection.

Fig. 2-4

The contours of a normal ear are drawn on a transparent X-ray film. The base of the future framework is drawn and will be used to select the most appropriate segments of rib cartilage.


Costal cartilage is the only autologous tissue in the body that has sufficient quantity and the physical properties necessary to sculpt the form of an ear and maintain that shape despite the deforming forces of skin retraction. However, a patient′s thorax must be sufficiently developed to have enough cartilage for a total ear reconstruction. In most patients, this occurs by about 8 to 10 years of age.


A small amount of thoracic asymmetry may be noted after the costal cartilage is harvested. However, aside from a short, 5 to 8 cm scar, it usually is not noticeable even in very thin children. The scar is routinely fine, fades with time, and is very well accepted by patients. The chest wall is often no more asymmetrical than that of unoperated patients.


We choose to harvest costal cartilage from the ipsilateral side, because our base piece will be taken with an intact synchondrosis and must be flipped over, maintaining the anterior perichondrium on the undersurface of the costal cartilage framework.


Analyzing a CT scan preoperatively may help to decide which costal cartilage segments to harvest. Sometimes the cartilage can be harvested leaving the costal margin intact, which reduces the palpability of the thoracic defect.

Fig. 2-5 This 50-year-old male underwent excision of a melanoma of his ear. We performed a subtotal reconstruction involving both the helix and antihelix. The sixth costal cartilage was sufficiently large and thick to allow carving of the base and antihelix in one piece. The helix was carved from the eighth costal cartilage and added to the base. The seventh costal cartilage was not harvested.

When harvesting the different segments of cartilage, surgeons should have in mind the various pieces needed and figure out how they will be positioned on the different segments.

Fig. 2-6 When harvesting in this patient, we encountered a very wide sixth costal cartilage segment with a curvature perfectly shaped for the base and carved the antihelix by harvesting part of the seventh rib. We obtained the helix from the eighth costal cartilage, which was very long. An advantage of this unusual costal cartilage harvest was maintaining the seventh costal cartilage continuity.

In total and subtotal ear reconstruction, the helix must usually be reconstructed in the framework. Most often, the eighth costal cartilage is used to re-create the helix. We have found that it must have a minimum length of 7 cm to re-create the curvature of the helix reliably, and any additional length can be added to its continuation along the straight posterior border of the ear.


We routinely harvest the eighth and ninth costal cartilage segments with all perichondrium attached. This is a much faster dissection than the subperichondrial approach and does not alter the incidence of thoracic wall deformity.


The sixth and seventh costal cartilage segments are harvested with the anterior perichondrium attached but leaving the posterior perichondrium in situ. This is done to reduce the risk of damage to the pleura.



Different Cartilage Configurations


The segments of costal cartilage can vary widely in shape and size.

Fig. 2-7 The segments of rib cartilage usually harvested are numbered on this scanner.


Pearl


The seventh rib is the last one to attach to the xiphoid. This is helpful for determining which rib is being harvested.


The number of segments harvested depends on the development of the thorax (which varies markedly between adults and children) and also on whether a complete or partial framework is required.

Fig. 2-8 The base is generally cut to include two adjacent ribs and their synchondrosis.

Thus it is necessary to find a suitable location for each piece. For unoperated patients at least 9 years of age, a sufficient amount of cartilage for reconstruction of an ear is always present in one hemithorax. Determining precisely the location of each piece becomes like a puzzle and must be planned while harvesting the cartilage.


The pieces required to carve a complete framework are a base, helix, antihelix, tragus-antitragus complex, a projection piece (PI) to be placed behind the root of the helix and tragus, in some cases a segment placed behind the antihelix (PII), and a segment of cartilage to be stored under the thoracic skin for use during the second stage, if necessary. Thus usually six or seven pieces of cartilage are fashioned from the harvested cartilage.


We routinely harvest ipsilateral cartilage, including the anterior perichondrium, with the harvested pieces but leave the posterior perichondrium in situ on the chest wall. The base piece is flipped over so it will retain perichondrium over the synchondrosis. For ears previously reconstructed using ipsilateral autologous rib cartilage, the reconstruction can be repeated using the contralateral side, but the base piece is not flipped over. Thus the main difference is that the costal cartilage will be harvested with both the anterior and posterior perichondrium attached to it. This ensures continuity at the synchondrosis for a better stability of the two adjacent segments of the base piece.


The cartilage can be used is various ways depending on the length and width of the pieces harvested. Several variations are possible, but what is important is to correctly choose the position of the base, to use the thickest cartilage available for sculpting the tragus-antitragus complex, and to have a sufficiently long helix (7 to 8 cm minimum).



Typical Situation

Fig. 2-9 This is a typical situation. The sixth through ninth segments of rib cartilage have been harvested, and a typical distribution of the different pieces has been drawn on the cartilage. Leftover cartilage is preserved as a single piece under the thoracic skin, to be used during the second stage. We routinely document the size of the retained piece using an intraoperative photograph and reference markings of a ruler in the image. It is useful to know the amount of cartilage available when planning the second stage. A TYPE I framework has been sculpted, with projection pieces under the root of the helix and the tragus (PI) and behind the antihelix (PII). (The different types of sculpture and projection are discussed later.)


Positioning the Pieces Needed to Construct the Framework

Fig. 2-10 The sixth through eighth ribs have been harvested. The base has been taken from the sixth and seventh, including the synchondrosis. The antihelix was harvested from the eighth rib, which was also used for the helix, and the tragal-antitragal complex from the thicker part of the seventh. The remaining cartilage was used for PI (the longest), and the two short segments remaining on the sixth and seventh ribs were fixed together with wire sutures and stored under the thoracic skin.
Fig. 2-11 The sixth through ninth ribs have been harvested. The antihelix and antitragus have been carved from part of the eighth rib, and the rest will be used for the helix. The tragus was harvested from the seventh rib. Part of the ninth rib was used for PI, and the remaining part was stored under the thoracic skin.
Fig. 2-12 The sixth through ninth ribs have been harvested. The antihelix was carved from the ninth rib and the antitragus and the tragus in two separate pieces from the sixth rib. The eighth rib is large and will be used for the helix, and the remaining part will be used for PI and for storage under the skin for the second stage.

In planning, surgeons should plan to bank a piece of cartilage for use during the second stage. It is placed just beneath the skin in the thoracic wound after rectus closure.

Fig. 2-13 A piece is routinely measured before it is banked. This is the exact amount of cartilage available for the second stage.

If a sufficiently large piece of cartilage is not available, small residual pieces can be wired together.

Fig. 2-14 Two fragments of cartilage have been fixed together with wire sutures.

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Related posts:

  1. CHAPTER 3 Stage II: Creation of the Retroauricular Sulcus
  2. CHAPTER 1 Principles of Two-Stage Autologous Ear Reconstruction
  3. CHAPTER 12 Reconstruction With Conchal and Costal Cartilage
  4. cHAPTER 9 Complications

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May 24, 2020 | Posted by in OTOLARYNGOLOGY | Comments Off on CHAPTER 2 Stage I: Reproduction of the Missing Contours

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