Overview of Graves Disease Orbital Decompression
Thyroid eye disease (TED), also known as thyroid-associated ophthalmopathy (TAO), thyroid orbitopathy, Graves’ orbitopathy, or Graves’ ophthalmopathy, can cause changes to your eyes and surrounding tissues. This disease can lead to swelling and sticking out of your eyes due to an increase in the size of the eye muscles and fat around the eyes with thickening, a condition called proptosis.
These changes in your eye and nearby tissues can cause pressing on your optic nerve (compressive optic neuropathy), dryness and inflammation of the cornea (exposure keratopathy), and trouble moving your eyes leading to double vision (ocular motility disorders). The treatment of proptosis or bulging eyes from thyroid eye disease often involves a surgery known as orbital decompression.
This operation increases space around the eyes by utilizing the nearby sinus spaces. The degree of decompression or the extent of the operation is based on each patient’s specific condition. So, in more severe cases, surgeons might need to create more space by operating on the inner, outer, and lower walls of the eye socket, involving nearby ethmoid sinuses, maxillary sinus, and the orbital trigone respectively.
Anatomy and Physiology of Graves Disease Orbital Decompression
The eye sockets, or ‘orbits’, house various parts of the eyes such as the eyeballs, muscles that help move the eyes, nerves, fat, and blood vessels. They are somewhat cone-shaped, narrowing from the front to the back. The average adult eye socket is about 35mm high, 45mm wide, and 45mm long and has a volume of 30 cubic centimeters.
The eye socket is made up of 7 different bones:
1. The ‘frontal bone’, which forms the forehead, and a part of another bone called the ‘sphenoid’, make up the top of the eye socket.
2. The ‘maxillary’, ‘palatine’, and ‘zygomatic’ bones create the bottom part of the eye socket.
3. The ‘ethmoid’, ‘lacrimal’, and a larger part of the ‘sphenoid’ bones form the inside wall of the eye socket.
4. The parts of the ‘zygomatic’ bone and the ‘sphenoid’ bone create the outside wall of the eye socket.
There are different approaches a doctor can take to perform medical procedures on the eye socket. For example, a surgical process called ‘medical wall decompression’ can be performed through a method called ‘transcaruncular approach’. Another surgical method, ‘transconjunctival approach’, is used to reach the bottom part of the eye socket. ‘Lateral wall decompression’ involves removing a deep bone within the outside wall of the eye socket known as the ‘trigone’. Also, the inside surface of the top and/or outside walls of the eye socket can be made thinner using a surgical instrument called a ‘burr’.
Why do People Need Graves Disease Orbital Decompression
Orbital decompression, a type of eye surgery, is typically performed for individuals experiencing severe eye issues. These conditions can include compressive optic neuropathy, exposure keratopathy, and proptosis. For simplicity, think of these issues as conditions that cause a lot of pressure or discomfort in the eye area.
Compressive optic neuropathy refers to damage of the optic nerve due to pressure, which can affect your sight. Exposure keratopathy occurs when the front of the eye, called the cornea, gets dried out because the eyelid cannot properly cover it. Proptosis is the medical term for bulging eyes, often caused by a condition like thyroid eye disease.
Three-wall decompression is a type of orbital decompression surgery that can help those with moderate to severe symptoms, especially those suffering from compressive optic neuropathy. This procedure seeks to alleviate the symptoms by creating more space in the eye area, lessening the pressure and discomfort. By potentially restoring normal eye function and positioning, this surgery can greatly improve a person’s quality of life.
When a Person Should Avoid Graves Disease Orbital Decompression
There are occasions where a patient might not be suitable for a surgical procedure. This could be because they are too unwell overall, or because they don’t want to risk the possible complications that surgery can bring. In certain conditions, it may not be totally out of the question, but should be approached with caution. These conditions may include:
Chronic sinusitis, which is a persisting inflammation of the sinuses. If a patient has an infection in the eye socket area or the orbits, surgery could potentially spread the infection. In cases where someone’s immune system isn’t functioning well, such as being immunocompromised, it might not be the best choice as they might struggle to recover post-surgery.
If a patient has bleeding disorders that make it hard to control bleeding, then surgery could be a bit too risky. Lastly, if a patient has atretic sinuses, which means that their sinuses are blocked or not fully developed, this could also be a stumbling block for surgery.
Equipment used for Graves Disease Orbital Decompression
The tools used by doctors can change based on the specific method and operation they are performing.
Who is needed to perform Graves Disease Orbital Decompression?
This means a specialized doctor who focuses on surgeries around the eyes and face or any surgeon who has taken extra schooling in orbital surgery, which deals with the area around your eyes. These trained experts know how to safely perform these detailed procedures.
Preparing for Graves Disease Orbital Decompression
For a thorough eye examination, your doctor will use a procedure that involves widening your pupils to take a better look into your eyes. This is called a dilated fundus exam. In addition to this, your doctor might conduct an imaging test using CT or MRI machines. This helps them to take a better look at the structure of your eyes and detect any potential issues.
Before a surgery, it is common practice for doctors to do an in-depth medical examination. This includes evaluating your physical condition and past medical history to ensure fitness for surgery. In certain cases, doctors may test your thyroid function, a gland in your neck that helps control your body’s metabolism, and the levels of acetylcholine receptor antibodies, proteins produced by your immune system that can affect muscle movement.
How is Graves Disease Orbital Decompression performed
The doctor starts the operation, known as 3-wall decompression with lateral orbital rim advancement, after having put you to sleep with general anesthesia. Then, you’re given a balanced mixture of numbing and constriction drugs to help decrease pain and blood flow in your eye area. This mixture gets injected near and under your eye (caruncle and inferior conjunctiva) using a transconjunctival approach. Before the surgery starts, your doctor prepares and covers your body in a way that only the surgical area is exposed and kept sterile.
A protective shield is placed over the cornea, that’s the clear, front surface of the eye, to avoid any damage during the surgery. Following this, a surgical cut starting at the side corner of your eye is made with a specific surgical blade. The doctor uses a special heat-based device to make a cut into the layer covering the bone of the side part of the eye area. Special tools called elevators are then used to separate this layer from the bone and muscle below.
The doctor then focuses on the bottom part of the eye area. A medical tool is used to pull back your lower eyelid while another tool is used to protect the eye. The same heat-based device is used to make a cut through the connective tissues and the layer covering the bone at the bottom of your eye. A special elevator tool is used to separate the bottom bone of your orbit (eye socket) from its covering.
The same process is followed for the medial wall or the part of your eye socket closest to your nose but via a trans-caruncular approach. Special scissors are used to make a surgical space near your caruncle (small pinkish lump at the inner corner of the eye) and another tool is used to separate the medial wall from its covering layer.
The process also includes creating a small window in the bone at the back of the bottom part of your eye socket. Special instruments then remove the extra bone from the bottom and medial parts of your eye socket. Once that’s done, a special medicine is used to help stop the bleeding. As a next step, a verical cut is made in the membrane covering the ocular contents, which causes the fat inside your orbit to move forward.
The last part of the procedure involves putting back the bone flap that was previously taken out. It is thinned and then placed again using special threads or a plate with screws. The surgical cuts made near the eye are closed using sutures. Finally, after the protective corneal shield is removed, an antibiotic ointment is applied, and you are woken up from anesthesia and taken to the recovery area where you’re closely monitored until you’re stable.
Possible Complications of Graves Disease Orbital Decompression
Graves’ Disease is a medical condition that often affects the eyes, causing discomfort and vision problems. To alleviate these symptoms, patients might undergo a surgery known as orbital decompression. However, like all surgeries, this procedure carries some risks of complications. Here’s a simplified list and explanation of what these complications might be:
* Orbital Hemorrhage: This is a medical term for bleeding in the area around your eye.
* Orbital Compartment Syndrome: This is when pressure builds up in the eye socket, which can cause pain and vision problems.
* Optic Nerve Injury: The optic nerve connects your eye to your brain, so any damage to it can affect your sight.
* Infection: As with any surgery, there’s a risk that the surgical area might become infected.
* Diplopia: This is what doctors call double vision.
* Restricted Motility: This means you might have difficulty moving your eye in certain directions.
* Subconjunctival Hemorrhage: This is when blood vessels break, causing redness in the white part of your eye.
* Vision Loss: Any surgery involving the eye carries a risk of vision loss.
* Globe Dystopia, Globe Rupture: These are serious complications involving damage to the eyeball structure.
* Hypoesthesia (V2): This is reduced sensation or numbness in the area of your face supplied by the second branch of the trigeminal nerve.
* Eyelid Retraction or Ptosis: This involves the position of your eyelid, either being pulled back or drooping.
* Vitreous Hemorrhage, Retinal Detachment: These are serious complications involving bleeding or a detached layer inside your eye, which can severely affect your vision.
* Cerebrospinal Fluid Leak: This rare complication involves a leak of the fluid that surrounds your brain and spinal cord.
* Lacrimal Drainage System Injury: This can affect your tears’ natural draining pathway, leading to teary eyes.
* Keratopathy: This term refers to any disease affecting the cornea, the clear front surface of your eye.
* Scarring: You might have visible scars in the area around your eye following surgery.
* Lid Laxity/Malposition: This can affect the position and tightness of your eyelid.
* Canthal Angle Distortion: This might alter the shape or position of the corner of your eye.
What Else Should I Know About Graves Disease Orbital Decompression?
Thyroid eye disease (TED) is a condition where the body’s immune system mistakenly targets the eyes, causing inflammation. This condition is most commonly linked with Graves’ hyperthyroidism, a situation where the thyroid gland produces too much thyroid hormone.
One of the major signs of TED is the pulling back of your eyelids, making your eyes appear larger or more protruded. The disease is also the most common reason for one or both eyes to bulge or pop out, which can be uncomfortable and noticeable.
About 90% of people with TED also have hyperthyroidism, but even people with normal or low levels of thyroid hormones can develop TED. Also, around 30% of people with Graves’ hyperthyroidism might have TED at the time they are diagnosed or might develop it later. It’s important to remember that the seriousness of TED doesn’t always align with the level of thyroid hormones in the blood.
Being a woman and smoking can both increase the risk of getting TED and make it more severe. TED can lead to decreased vision due to pressure on the optic nerve (the nerve that connects the eye to the brain). This occurs in roughly 2% of those who have TED and is considered a medical urgency, requiring a procedure called orbital decompression to relieve the pressure and protect vision.