viernes, 26 de abril de 2019

What is Frontalis Suspension?

Download PDF Copy

By Chloe Bennett, B.Sc.Reviewed by Dr. Liji Thomas, MD

Frontalis suspension is a common surgical method used by medical professionals to correct drooping of the upper eyelid due to poor function of the levator muscle. Through the procedure, the eyelid is reconnected to the brow using a sling-type material, making use of the frontalis muscle to effectively elevate the eyelid.

What is frontalis suspension?

Also known as brow suspension, frontalis suspension (FS) is a surgical procedure used to improve eye functionality in individuals with blepharoptosis and poor levator muscle function. Blepharoptosis is an ocular condition in which the upper eyelid margin is significantly lower in position than when the eye is in primary gaze. The condition is thought to occur due to weakness in one of the two upper lid elevators.

Blepharoptosis has several subtypes depending on a range of parameters, including but not limited to levator function, etiology, severity and age of onset. Furthermore, the subtypes may be divided by cause into five main categories; traumatic, neurogenic, myogenic, mechanical and aponeurotic.

There are three categories of levator function. Poor function typically refers to a levator function of approximately 4mm. Fair functionality is seen when the levator function is between 5-7mm, while good function refers to 8mm or more of eyelid elevation.

During the procedure, a sling material is used to connect the eyelid to the brow. There is a range of sling materials offered, such as preserved donor sclera, muscle tendon, gold, silver and platinum wires. However, the most widely used material is autogenous fascia lata, though synthetic sutures and graft materials are also used, with varying rates of success and complications.

When is frontalis suspension used?

For individuals with congenital ptosis, surgical intervention is often delayed until the patient is 3-5-years-old. This enables proper growth and maturation of the child’s face as well as ensuring that they can cooperate during the preoperative examinations.

It is thought that approximately 20-70% of those with simple congenital ptosis will go on to develop amblyopia. This is often the case in individuals with unilateral congenital ptosis. Amblyopia is often linked to astigmatism above 1.5 diopter, as a result of pressure on the cornea exerted by the upper eyelid.

In view of this, it is vital that FS be used for early surgical repair to reduce the likelihood of developing amblyopia.

Finally, patients with a history of quite recent traumatic or neurogenic ptosis may be advised to wait for 6-12 months before undergoing FS to allow spontaneous resolution where possible.

Preoperative examination

Typically, prior to undergoing frontalis suspension, several examinations and questions need to be explored. These include gathering family and birth history, ophthalmologic examination of the eyelid, tests of refraction and visual acuity, and general examinations including blood and thyroid function tests.

By evaluating an individual’s birth history with suspected blepharoptosi, medical professionals are able to identify cases of traumatic delivery. Taking the family history into consideration can also allow them to identify the probability that thyroid eye disease, muscular dystrophy or mitochondrial myopathies are present.

The height of the eyelid is also measured, specifically, the distance from the upper eyelid margin to the light reflex on the cornea, which is referred to as the margin reflex distance-1.

Surgical approaches for frontalis suspension

Several surgical techniques have evolved to connect the eyelid and brow area. The majority of the techniques require cutaneous incisions to be made at the tarsus level and the eyebrow. This allows the sling material to be passed through the incisions in a suborbicularis plane.

Single rhomboid, double rhomboid, double trapezoid, single triangle, double triangle, single pentagon and double pentagon are just some of the suture designs used in frontalis suspension. Specific designs are preferred depending on the characteristics of the individual undergoing surgery. For example, a single rhomboid loop is often used for young children because it has been found to prevent postoperative bending of the eyelid.