Around 1 in 6000 babies born in the United Kingdom are diagnosed with microtia - a condition present from birth, where the cartilage of the outer ear is underdeveloped.¹

Microtia can lead to difficulty hearing and can affect language development and communication skills, not to mention psychological and social implications, potentially resulting in avoidance behaviour and isolation in children.² This can have a major impact on people’s lives, calling attention to the importance of corrective surgeries.

Understanding microtia

Before delving deeper into the surgical options available to correct microtia, let us first take a deeper look at what the condition exactly is. 

First, let’s start by talking about the basic structure of the ear.

The ear itself can be divided into three parts: outer, middle and inner. Microtia, we’ve established, affects the cartilage in the outer ear. Most people with microtia have what is called unilateral microtia,³ i.e. only one ear is affected, and more people have their right ear affected compared to their left.⁴

What are the risk factors? 

To answer this, we’re going to divide risk factors into two broad types - genetic and environmental. Genetic risk factors include being biologically male as well as having other congenital disorders like Goldenhar syndrome or microsomia, while environmental risk factors include diabetes, maternal anaemia during pregnancy and a higher maternal or paternal age. The exact cause for microtia, however, remains a mystery.⁵

The most widely used classification system categorises the condition into three grades, from mild (grade 1) to severe (grade 3). Below is a more detailed description of the classification system.⁶

Grade I. Abnormal auricle (visible part of the outer ear) with all identifiable landmarks. 

Grade II. Abnormal auricle without some identifiable landmarks. 

Grade III. Very small auricular tag or anotia. (absence of the external ear/auricle) 

Preoperative considerations

Surgery can be a life-changing decision in an individual’s life. Before taking this leap, there are a few factors that need to be considered by the healthcare team. The first is an evaluation of the patient, which may include their medical history (for example, the grade of microtia, any other medical conditions, etc.), a variety of physical examinations and a hearing assessment.

Following this initial assessment, there are usually imaging studies that provide a deeper understanding of the current situation. An example of this includes CT scans for temporal bone analysis, which would provide deeper insight into the condition of the bones of the skull on the side of the head, which contain various structures such as the middle ear, cranial nerves and blood vessels.

After careful analysis of these factors comes preparing for the surgery itself. Here, like all stages of treatment, a multidisciplinary team approach is taken, where various professionals including otolaryngologists, plastic surgeons, audiologists and psychologists discuss the next steps along with the patient’s family. They present various options depending on what would be most beneficial to the most important member of the team, the patient themself.

Surgical options for microtia correction

There are many surgical options for the reconstruction of microtia, from autologous ear reconstruction to the use of prosthetic frameworks. Let us now take a closer look at some of these options, carefully weighing the pros and cons and analysing them in detail.

Autologous ear reconstruction

The benchmark technique for autologous ear reconstruction uses rib cartilage to reconstruct the outer ear. This surgery uses the patient’s own tissue and is done in either two stages, as detailed below:

Stage 1: Cartilage Harvest and Framework Creation

First, some cartilage is taken from the patient’s rib and remodelled into the outer ear. This is usually done when the child is between 8 to 10 years old, which is when they have enough cartilage in the ribs to be taken. The operation lasts 5 to 6 hours under general anaesthesia and once harvested, the cartilage is used by a prosthetist to make a framework, mirroring the other ear as much as possible. After this, the new ear is inserted under the skin at the side of the patient’s head.

Stage 2: Ear Elevation and Refinement

In the second stage, the ear is lifted so that it’s at a normal angle to the side of the head, rather than flush against it. This takes three to five hours and involves adding a flap of cartilage behind the ear to cover the exposed parts. Sometimes, there is also a third stage where the final results are refined.

As the patient’s own tissue is used in this technique, the risk of ulceration is minimal and the tissue will heal well if damaged, making it more sustainable in the long term. However, this method means an incision would have to be made at the ribs and the operation can only be started when the child is older so that enough cartilage can be harvested.

Insertion of a prosthetic under the skin

Instead of using rib cartilage, this technique uses either a plastic or sometimes silicone prosthetic, which is then inserted under the skin in a similar way to autologous ear reconstruction.

The surgery is done in one stage and there is no need for cartilage harvesting, meaning the procedure can be done at an earlier age. However, there is a risk of ulcerating plastic which makes this a less favourable option for some.

External prosthesis fitted to the side of the head

Another option is to wear an external prosthesis over the skin. A realistic-looking silicone ear can be made by a prosthetist, with pigmentation that matches the child’s skin tone and blends in. The prosthesis can be secured to the head in one of two ways – a special glue or anchoring it to the bone. The bone-anchoring option is a more permanent solution.

To fit the false ear by anchoring it to the bone, titanium implants are inserted into the bone, securing the prosthesis to the side of the head. This is done over two operations.

There is no risk of plastic ulceration, but the titanium implants may get infected, so these must be watched out for. Psychological adjustments may also be needed when helping the patient incorporate the prosthesis into their life.

Postoperative care and complications

Following the operation, there are several steps still to be taken to ensure the result is as optimal as possible for the patient.

In the short term, immediate post-operative care includes appropriate wound care and pain management for the child. Subsequently, longer-term follow-ups must also be incorporated so that any complications can be caught early and monitored as well as corrected by revision surgeries if necessary.

Some common complications to look out for include infection, framework exposure (where a part of the cartilage framework in autologous ear reconstruction is exposed to the external environment) and cartilage resorption (usually as a consequence of infection). However, it is important to consult with the doctor about any specific red flag complications to keep an eye out for, as these may vary depending on the patient and the surgery they have undergone.

Advances in microtia reconstruction

Ear reconstruction surgery remains one of the most challenging fields in reconstructive surgery. This, coupled with the major impact microtia has on patients and their loved ones, highlights the importance of new advances in ear reconstruction surgeries.

One new technique being explored is the use of 3D printers to create custom implants.⁷ As the majority of patients with microtia are affected unilaterally, a 3D model can be designed based on the unaffected ear. This new method would only take approximately half the time that autological ear reconstruction does not require any cartilage to be harvested, meaning it could be performed at an earlier age for the child.

Another emerging option for microtia revolves around tissue engineering and regenerative medicine.⁸ This uses cells and other biomaterials to rebuild tissues and organs that can then be implanted under the skin at the side of the head. This, like autologous ear reconstruction, means better healing and reduced risk of ulceration. As the patient’s own tissue is grown and used instead of a foreign body, this technique would minimise the risk of tissue rejection.

Summary

Microtia can have a huge impact on patients’ lives, both physically and mentally, especially growing up. This makes the need for appropriate and optimal care crucial, both in terms of treatment of the condition itself as well as the impact of the consequences on the patient’s mental well-being.

Of course, every individual is different and so the treatment plan for microtia, like many other conditions, must be personalised according to each particular patient and their needs. While a variety of surgical options, from autologous ear reconstruction to the use of prosthetics, are currently available to be explored, there is still plenty of room for further research and innovation in this key field. We look forward to tracking the progress of promising new advances in the way we treat microtia. 

With the use of new 3D printing technology and tissue engineering, the future looks bright indeed.