LAS VEGAS – Knowing and respecting the anatomy of the levator muscle can help clinicians steer clear of complications from blepharoplasty and manage ptosis, according to Dr. Marc S. Cohen.
"It’s very helpful if you have a good understanding of how to find the levator muscle during eyelid surgery," said Dr. Cohen, an ophthalmic plastic surgeon at the Wills Eye Institute, Philadelphia. "In order to do this, you need to understand the relationship between the levator and the other eyelid structures."
Courtesy Dr. Marc S. CohenDr. Marc S. Cohen
The levator muscle elevates the eyelid and helps form the eyelid crease. It also creates the margin contour. As the levator muscle approaches the eyelid, it changes direction from vertically oriented to horizontally oriented. The muscle then advances inferiorly toward the eyelid margin, "and for the final centimeter or so, it becomes a fibrous aponeurosis, which attaches to the tarsus posteriorly," said Dr. Cohen, who also has a private cosmetic surgery practice. Behind the levator muscle are Müller’s muscle and the conjunctiva.
Whether a surgeon performs blepharoplasty with a CO2 laser, a blade, cautery, or radiofrequency, the first structure encountered posteriorly is the orbicularis oculi muscle, which closes the eyelid. "It’s highly vascular, and is the site where most of the bleeding occurs during blepharoplasty," Dr. Cohen said at the annual meeting of the American Academy of Cosmetic Surgery.
The next layer contains the orbital septum. "It’s important to understand that the septum does not travel all the way to the eyelid margin," he added. "The septum starts at the orbital rim and attaches to the levator muscle. This layer really has two structures: the septum and the levator. Behind the septum are the eyelid fat pads."
In a dissection above and behind in the eyelid, the septum and the fat precede the levator muscle. However, in the inferior eyelid, the levator is just deep to the orbicularis muscle. Beneath the fat, the levator muscle moves posteriorly into the orbit; this causes it to narrow.
"Lateral to the muscle at this point is the lacrimal gland, but medially is just orbital fat," Dr. Cohen said. Upon reaching the orbicularis muscle, the goal is to protect the levator muscle. "The levator muscle is protected by septum fat superiorly, whereas more inferiorly the levator fuses with the orbicularis, so this is a danger zone," Dr. Cohen said. "Laterally is the lacrimal gland and supramedially is the safest point, because there you have the fat, and nothing else to really worry about superficially. So what you do is press on the globe through the eyelid, have the fat prolapse forward, and dissect there."
Reattaching the levator muscle can be tricky in the context of levator resection ptosis surgery, said Dr. Cohen. "Where you make the attachment is going to affect the contour postoperatively," he said. "Grasp the tarsus and pull it upward to see if you have obtained a natural curve. If you grasp it at the wrong point, you’ll have a curve that’s not aesthetically pleasing," he cautioned.
"When you get the right point, that is where you are going to put the sutures to reattach the levator. A double-armed 6-0 suture is passed in a horizontal mattress fashion, partial thickness, through the tarsus. The suture is then passed in a posterior to anterior direction, which shortens the levator muscle."
Placement of the suture determines how much the muscle shortens. "The suture is then temporarily tied, and the patient is asked to open their eyes to assess the height and the contour," Dr. Cohen said. "If you need to adjust height vertically, you can move the suture vertically on the levator muscle. If there’s a problem with the contour, you change the fixation point to the tarsus. Then the suture is permanently tied and the skin is closed."
Dr. Cohen warned about the risk of complications from blepharoplasty in patients with active Graves’ disease, a common autoimmune condition that can cause hyperthyroidism and fibrosis of the extraocular tissues. The severe form of Graves’ disease can cause eyelid retraction, difficulty closing the eyes, double vision, and anterior displacement of the globes. "Many patients present with much more subtle findings," he noted. "For example, fibrosis of the levator with lid retraction is a common presentation in women aged 40-60 – the same demographic that tends to have blepharoplasty. It’s often subtle and underdiagnosed."
Patients with undiagnosed Graves’ disease prior to a blepharoplasty "can develop signs and symptoms which are indistinguishable from the complications of blepharoplasty," Dr. Cohen said. "You need to make the diagnosis before surgery and make sure the disease has stabilized before you do any surgery. That happens on average in about 18 months but is variable."