Surgical Interventions in Thyroid Eye Disease
Indications for Surgery
Elective surgery is generally appropriate when the following occurs:
Thyroid eye disease has been stable for several months.
Clinical activity score is low (1-2 or less).
Thyroid function under control.
Emergent/urgent surgery is generally appropriate for vision-threatening circumstances:
Optic neuropathy
Severe proptosis with corneal injury
Procedures for TED Treatment
Surgical interventions in thyroid eye disease include orbital decompression, strabismus surgery, and eyelid retraction repair.
Orbital decompression involves removing fat and bone from behind the eye(s) to help them recede into the orbit. Strabismus surgery moves the eye muscles to realign the eyes. Eyelid retraction repair repositions the eyelids, so they are no longer pulled back too far. Therefore, measurements of proptosis using a Hertel exophthalmometer, eye alignment, and eyelid position are taken every 4 to 6 months to assess for stability. In general, when all three parameters are stable over two or more visits, then consideration can be given for restorative surgery. The time from thyroid eye disease onset to inactive, stable disease is approximately 1 to 3 years, but can persist for several years.1
Presurgical Evaluation
The clinical activity score (CAS) is a construct of signs and symptoms where each parameter is given a binary 0 or 1 value. Symptoms include pain and pain with eye movements. Signs include conjunctival injection, caruncle/plica inflammation, eyelid edema, chemosis, change in proptosis, change in eye movement, and loss of visual acuity.2 The CAS can be somewhat subjective in that a patient may have a red eye, but the redness may not be solely the result of thyroid eye disease, and the clinician must decide whether to score the patient in the CAS.
Findings of compressive optic neuropathy include loss of visual acuity, visual field loss, color vision loss, changes in pupillary function, and the optic nerve appears normal, pale, or swollen. CT of the orbit will show enlargement of the extraocular muscles crowding the optic nerve at the orbital apex. These patients require urgent high-dose corticosteroids and orbital apex decompression. Often, the posterior medial orbital wall will be decompressed to allow room for the medial rectus to spread out into the paranasal sinuses and exert less pressure on the optic nerve.
In some cases, individuals will have severe proptosis or eyelid retraction that does not allow the eyelids to close over the cornea fully. This can lead to corneal dryness, ulceration, and infection. Corneal scarring and perforation may result, leading to permanent vision loss. These patients may require a tarsorrhaphy (partially sewing the eyelids shut) to give better corneal coverage. In general, an orbital decompression would not be performed in this situation.
Preoperative Considerations
Orbital decompression and strabismus surgery are typically performed under general anesthesia, and the eyelid surgery is typically performed under local plus monitored anesthesia care. Patients will require a preoperative history and physical.
Thyroid eye disease can worsen with radioactive iodine treatment for Graves’ disease but does not change with thyroidectomy. Individuals with Graves’ disease who do not have thyroid eye disease are not at increased risk for developing thyroid eye disease with radioactive iodine. Normalization of thyroid function does not affect the course of a individual’s thyroid eye disease. Smoking has been shown to worsen thyroid eye disease, and it is recommended that patients stop smoking. Secondhand smoke has not been studied in this regard, but avoiding it is often recommended.
Nonsurgical TED Treatments
Corticosteroids can mitigate signs and symptoms of thyroid eye disease. However, once the course of steroids is finished, the symptoms often recur. In general, corticosteroids do not shorten the active phase of the disease. In our experience, oral corticosteroids appear to prolong the course of the active phase. At this time, patients with severe active thyroid eye disease receive intravenous methylprednisolone 500 mg weekly x 6 weeks followed by 250 mg weekly x 6 weeks.3
Radiation for active thyroid eye disease is controversial with data supporting its use and other studies arguing against any benefit.4 It is often given over the course of 10 days. Radiation doses often range from 1.8 to 2.0 gray, which is a relatively small dose. New literature has suggested that doses of 0.2 to 0.5 gray may be effective, but that has not been my experience.
Teprotumumab can be considered for individuals with active thyroid eye disease. It is given as an infusion once every 3 weeks for a total of 8 infusions. There are a number of inclusion and exclusion criteria, and it is often rejected by insurance companies because of its high cost. It is important for the primary care physician to note that it may lead to elevated blood sugars and hearing loss. Audiometry is often performed before, during, and after the treatment course.
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