Affecting one in 6,000 live births worldwide, microtia can appear in isolation or as a feature of other syndromes, such as hemifacial microsomia or Treacher-Collins syndrome.
Microtia usually affects one ear only (unilateral microtia), although in 10% of cases both ears are involved (bilateral microtia). The root cause of the problem is thought to relate to an interruption of the blood supply to the affected area about eight weeks after a baby’s conception. Hearing is often impaired on the affected side due to the ear canal being underdeveloped, although a hearing aid is only usually needed in cases of bilateral microtia.
What surgery is available, and what techniques are involved?
There are three main reconstructive options available to patients with microtia. The first is autologous ear reconstruction, which means reconstruction using the patient’s own tissue. The second option involves utilising a prosthetic framework covered or buried under the patient’s own skin. The third option is to use an external prosthesis crafted to match the opposite ear and fitted to the side of the head.
The gold standard technique for autologous ear reconstruction is a rib cartilage graft; a surgical intervention that is usually carried out in two or three stages. The first stage of surgery is conducted when a child is between the ages of eight and ten, when there is sufficient volume of cartilage in the chest area. With the patient under general anaesthetic, rib cartilage is harvested via a small incision at the side of the chest in an operation lasting between five to six hours.
Once removed, the pieces of cartilage are then carved and joined together to create a framework replicating a new ear. Based on a map of the patient’s other ear the framework is as close as possible to a mirror image of the opposite ear. Once complete, the new ear structure is buried under the skin at the side of the head. Occasionally if the skin is scarred or the hairline is very low the ear maybe covered by a flap of fascia from under the scalp and a split skin graft. (A flap is a piece of living tissue that is transferred from one part of the body to another, along with the blood vessels that keeps it alive.)
Patients and families should note that in the past surgeons have attempted to use cartilage from mothers and from human donors. The cartilage gradually disappeared and the results were poor. More recently scientists have created ears made of engineered cartilage in laboratory mice. Although promising this technology does not work in humans as the cartilage is too soft.
The newly constructed ear initially lies flush against the patient’s head. Six months later at the second stage the ear is lifted to achieve a normal projection. This procedure takes from three to five hours and involves inserting a wedge of cartilage behind the ear with fascial flaps and skin grafts used to cover the exposed surfaces.
Sometimes a third operation is required to refine the results or to perform additional procedures such as piercing the lobe or correcting prominence of the opposite ear. Occasionally a course of laser treatment maybe required if there are a few hairs growing on the ear.
A buried prosthesis
Patients also have the choice of prosthetic ear reconstruction. Rather than using cartilage fro the chest some surgeons utilise frameworks made of hard porous plastic material or even silicone. This is buried under the skin or a fascial flap and skin graft in much the same way as the cartilage framework. The reconstruction can be completed in one stage.
The final option is to wear an external prosthesis on top of the skin. A skilled prosthetist can create a very realistic ear using silicone. Pigments are used to give a realistic skin colouration. Patients may even be provided with a false ear for the summer and one for the winter. These external prosthesis maybe secured with special glue or alternatively, patients can opt for a more permanent bone-anchored prosthesis. This type of false ear is secured via two or three small titanium implants which are embedded into the bone at the side of the head over the course of two operations
Who should I expect to see as a patient?
Patients undergoing the first stage of autologous ear reconstruction will need to be kept in hospital for four to seven days. Very small suction drains left in at the time of surgery and are used to suck the skin onto the new ear. These are removed after four or five days. Skin stitches are removed after a week.
It takes several months for the swelling to settle but the shape of the new ear will be apparent to all at an early stage. A week after the second operation, the skin graft will need to be checked. Patients should avoid all sporting activity for three months, but should rest assured that long-term satisfactory outcomes can be expected following autologous ear reconstruction.
What should I expect as a patient?
Of the reconstructive surgical options, autogenous reconstruction is widely regarded as the gold standard. Since the patient’s own tissue is used the new reconstructed ear is very much part of them. It is robust and will heal if injured and there is minimal chance of infection or ulceration in later life. Ear reconstruction using rib is however regarded as a highly skilled procedure and patients are advised only to have this surgery in a centre of excellence.
The main advantage of ear reconstruction using a buried plastic or silicone prosthesis is that there is no chest donor site. Thus one avoids a cut on the chest and the use of rib cartilage. This also means that the surgery can be performed at a younger age. However the long term risk of the plastic ulcerating though the skin makes this technique less popular worldwide. In a large series of such operations from China 13.5% of patients had problems with extrusion of the plastic through the skin. If the plastic becomes exposed it is likely to become infected and becomes a difficult problem.
The use of an exernal prosthetic ear is relatively safe although the small titanium anchors can become infected. There can be difficulties finding a good skin-colour match and patients often report a sense of being incomplete arising from the daily removal of a false ear. Significant psychological adjustments are often required as patients incorporate the prosthesis into their lives.