MICROTIA RECONSTRUCTION

MICROTIA RECONSTRUCTION
What is microtia?

Microtia encompasses a spectrum of congenital anomalies of the external ear and is often associated with abnormalities of the ear canal. The ear is one of the most intricately designed structures in the human body; therefore, adequate reconstruction is often quite difficult to achieve. Most children with microtia also have associated hearing loss, so treatment requires attention to both hearing restoration and ear reconstruction.

How common is microtia?

Microtia occurs anywhere from 1 in 5000 to 1 in 20,000 births. Males are at increased risk compared to females. Most of the time, microtia only occurs on one side (more on the right side). Incidence also varies based on ethnicity. It is much more prevalent in Native Americans, Asians, Pacific Islanders, and Hispanics and less prevalent in African Americans and Caucasians. For this reason, microtia is actually much more common in Texas and the Southwest compared to other parts of the country.

The cause of microtia is not yet fully known. Approximately 50% of cases are associated with other syndromes. When not associated with a syndrome, there is speculation about vascular compression during development, exposure to certain medications (Thalidomide, Accutane, Clomid), and possibly even high altitude.

What other conditions are associated with microtia?
  • Treacher-Collins syndrome – Vertebral Anomalies
  • Branchio-oto-renal syndrome – Macrostomia
  • CHARGE – Oral clefts
  • Goldenhar syndrome – Facial asymmetry
  • Chromosome 13 deletion – Kidney defects
  • Townes-Brocks syndrome – Heart defects
  • Nager syndrome – Microphthalmia
  • Miller syndrome – Polydactyly
Evaluation: A Multidisciplinary Approach

Because of the complexity of issues associated with microtia, it is ideal to have a team of    experts treating your child with frequent communication and collaboration. Members of this team include:

  1. Otologist (ear surgeon) and Audiologist: Monitors hearing and treats infections as needed, discusses options for hearing amplification, and discusses options for ear canal reconstruction or Bone Anchored Hearing Aid (BAHA)
  2. Facial Plastic Surgeon: Discusses timing and options for ear reconstruction
  3. Child Psychiatrist: Evaluates self-esteem issues, bullying, and/or problems in school
  4. Oral and Maxillofacial Surgeon or Craniofacial Surgeon: Manages associated craniofacial and dental problems
  5. Pediatrician: Assesses overall health, scoliosis, renal issues, etc.
What are options for ear reconstruction in microtia?

Goals of Surgery:

  1. Choose a method that is safest and most effective for the patient
  2. Achieve comparable height and projection to the other ear
  3. Allow patients to wear glasses
  4. Attain definition of all parts of the ear

Above: Dr. Saxon having lunch with Dr. Nagata and colleagues from the University of Mexico

The gold standard for reconstructing the ear involves taking cartilage from the rib and rebuilding the outside part of the ear. Much like sculpting, the outcome is highly dependent on the skill and artistry of the surgeon. Using rib cartilage is ideal because the patient’s own tissue is used and there are no problems with extrusion as is the case with the use of Medpore. Dr. Saxon has extensive experience in microtia reconstruction both from her training in New Mexico and with spending time with Dr. Satoru Nagata in Japan.

The Nagata technique for ear reconstruction is different in that there are only 2 stages of surgery instead of 4 using the Burt Brent technique described in the 1980s. The aesthetic of the ear is better; however, more cartilage is needed to achieve this. Chest circumference is measured at each visit with Dr. Saxon, and surgery can be scheduled when the chest measures 60 cm which is at about 10 years old. This is also an ideal age for surgery because children can decide for themselves whether they want surgery or not and actively participate in caring for their ear after surgery.

Dr. Saxon also has done research in minimizing pain in the chest after this procedure. There are two different options which are discussed in the preoperative clinic visit. The first is using regional anesthesia to perform a paravertebral nerve block prior to starting the surgery after a patient is under anesthesia. This minimizes the pain response during and after surgery and decreases the overall amount of narcotic medication given throughout the case. The second option is to leave a small catheter in the chest after surgery with a continuous infusion of local pain medication for several days. Both options are effective methods for management of pain after surgery, and most children go home the day after surgery.

Harvested rib cartilage


Completed ear construct with paper template

 

 

 

 

 

 

Other options for reconstruction include use of a Medpore implant or applying a prosthesis. A Medpore implant is a synthetic material that can be used instead of rib cartilage. It is quicker with no chest wall incisions or pain. The drawback is that the implant can become infected necessitating removal. Any salvage reconstruction in this situation, although possible, is much more difficult.

Before


After

 

 

 

 

 

 

 

 

Examples of result using Nagata Technique. Photos taken from Pediatric Plastic Surgery Ch 51: Auricular Reconstruction: Congential Auricular Defects – Microtia

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