DISEASES AND TREATMENTS

Marcus Gunn syndrome

What is Marcus Gunn syndrome or Jaw Winking Ptosis?

The Marcus Gunn syndrome or Jaw Winking ptosis is a type of ptosis It is characterised by abnormal movement of the eyelid when the jaw is moved. The movement is due to a developmental abnormality that affects a branch of a nerve of one of the jaw muscles, typically the lateral pterygoid muscle, which connects to a branch that weakens the levator muscle. When the pterygoid muscle contracts, the other muscle contracts, causing an aberrant, fluttering movement of the eyelid. In our experience, very few children with this syndrome do not suffer ptosis.

When treating children with Marcus Gunn syndrome, we have two main criteria. The first is to determine the degree of ptosis and the best way to correct it. The second is whether the abnormal movement warrants correction. In 99% of cases, the movements must be corrected because they are unsightly and draw the attention of others. We have seen that, among adults who have not undergone surgery and those who have undergone ptosis surgery without correction of the abnormal movement, all have expressed a desire to correct the abnormality because it prevents them from leading a normal life. They must make an effort not to move their jaws to avoid triggering the reaction, which has a psychological impact, as they all want to correct the abnormality and therefore consider it to be highly important to seek treatment during childhood.

Treatment

The only known treatment is to sever the levator muscle, which leaves the patient with complete ptosis but prevents occurrence of the abnormality. We correct complete ptosis with frontalis suspension, usually through frontalis flap surgery.

In cases of complete ptosis, the eyelid has no movement, due to the levator muscle, and we raise it with frontalis surgery. This creates a marked difference in relation to the movement of the other eyelid, which has an acceptable downward range of movement, whereas the operated eye has a more limited range. For the purpose of preventing the downward asymmetry, we recommend bilateral surgery, which may involve severing of both levator muscles and frontalis suspension or only severing the muscle of the affected eye and bilateral frontalis suspension.

Conservation of the levator muscle of the unaffected eye is the option chosen by most parents today, although there is little difference when the frontalis muscle works correctly.