Orbital decompression surgery is being increasingly used in the treatment of urgent and nonurgent complications related to Graves ophthalmopathy. An understanding of the specific indication for pursuing surgery is critical in deciding the optimal timing of the surgery, formulating the surgical plan, and determining the most relevant clinical outcomes. Quality-of-life (QOL) outcomes are also gaining increasing importance in assessing surgical success.
Surgical Indications
Graves Ophthalmopathy
Graves ophthalmopathy, also known as thyroid eye disease (TED), is the most common indication for orbital decompression surgery.
Urgent Indications
Dysthyroid (compressive) optic neuropathy (DON), which has an estimated incidence of 3% to 9% in patients with TED, is an urgent indication for orbital decompression surgery. Extraocular muscle enlargement restricting the vascular supply to the optic nerve is the most well-accepted mechanism of DON. The diagnosis is challenging and controversial. It is considered primarily a clinical diagnosis, evidenced by decreased visual acuity, a relative afferent pupillary defect, altered color vision, optic disc abnormalities, and visual field defects. Studies have also investigated the diagnostic role of imaging, in particular computed tomography (CT), in assessing features associated with DON, including muscle enlargement, crowding of the orbital apex, and prolapse of fat through the superior orbital fissure. Magnetic resonance imaging may also be useful to evaluate changes in the optic nerve. Once the diagnosis is made, first-line treatment typically consists of pulsed high-dose intravenous steroids. Orbital radiation therapy, which can be used alone or in combination with steroid treatment, has been shown to be particularly useful in the treatment of mild to moderate active TED and in improving extraocular movements. Orbital decompression surgery is considered if the response to these interventions is poor and/or if there is clinical worsening. Surgical approaches and the extent of bony wall removal vary and are covered in detail in Chapters 20 and 21 , but it is worth noting that in DON, decompression of the medial orbital wall is particularly critical, as this can be achieved most completely along the length of the intraorbital portion of the optic nerve.
Severe corneal exposure can also lead to vision loss. In TED, persistent eyelid retraction related to inflammation and scarring of the eyelid retractors and the Whitnall ligament commonly results in lagophthalmos, increasing corneal exposure. Worsening proptosis can further increase corneal exposure and predispose patients to ulceration and subsequent vision compromise. If this exposure proves refractory to conservative measures, such as lubrication, lid taping, and botulinum toxin injections, orbital decompression surgery is urgently indicated.
Nonurgent Indications
Medical therapy, including oral and intravenous steroids, is generally pursued initially in the absence of immediate surgical indications. In a recent survey of the American Society of Ophthalmic Plastic and Reconstructive Surgery, 83% of respondents preferred steroids as first-line treatment compared with only 10% of respondents who preferred orbital decompression surgery. As second-line and third-line treatment, 39% and 61% of respondents, respectively, preferred orbital decompression surgery. Most patients respond well to conservative measures, but an estimated 5% undergo orbital decompression surgery in the first year after diagnosis and up to 20% in the first 10 years after diagnosis.
Nonurgent indications for orbital decompression surgery include diplopia, proptosis, orbital and retrobulbar pain, and ocular hypertension. Surgery may also be indicated to improve cosmesis in TED. It is generally recommended to avoid performing surgery in the inflammatory phase of TED, as studies have shown that surgical manipulation during this phase may significantly worsen orbital inflammation. Orbital decompression surgery is typically recommended to be performed first before addressing the extraocular muscles and eyelid surgically.
Additional Indications
Although TED is the most common indication for orbital decompression surgery, it may be indicated for other reasons. These include iatrogenic complications, such as orbital hematomas, trauma-related issues, neoplasms, and for cosmesis in patients with proptosis for other reasons.
Surgical Contraindications
There are no absolute contraindications to orbital decompression surgery specifically. The surgery, however, does require the use of a general anesthetic, and patients may have comorbid conditions that affect their candidacy as in any other surgery. Patients taking anticoagulants should ideally discontinue them perioperatively, as bleeding can limit intraoperative visualization and increase the risk of postoperative hemorrhage. Patients with concurrent chronic sinusitis should receive appropriate medical therapy to treat chronic sinusitis, e.g. oral steroids and/or antibiotics, to optimize healing after surgery. The surgical plan may also involving opening diseased sinuses such as the frontal and sphenoid that are not necessarily required in orbital decompression surgery.
Patient Selection
The ophthalmologist typically identifies patients who meet indications for orbital decompression surgery, subsequently referring them to the otolaryngologist if an endoscopic approach is being considered. In a study of factors associated with greater quality of improvements after surgery, only nonwhite ethnic background was identified as a positive predictor, indicating that the benefit after surgery may be difficult to predict based on a patient’s characteristics, history, and clinical presentation and evaluation. This study also found possible concurrent clinical depression and anxiety in 26% and 37% of patients, respectively, lending support to addressing comorbid psychiatric conditions to optimize outcomes.
Decompression can include fat and/or bone removal, and patient selection also involves deciding whether the risk/benefit ratio is optimal with fat removal alone, bone removal alone, or fat and bone removal. Recent data have shown that fat removal achieves particularly reliable results in patients with proptosis secondary to either expansion of the fat compartment or enlargement of extraocular muscles, but not both, suggesting that in these patients it may be considered as a stand-alone option.
Outcomes
The relevant outcomes of orbital decompression depend on the specific surgical indications. They can generally be divided into the following categories: clinical outcomes, radiographic-based outcomes, and QOL outcomes ( Table 19-1 ).
| Outcomes | Quoted Values | References |
|---|---|---|
| Clinical | ||
| Rate of visual acuity improvement (%) | 82 to 88 | 1, 10, 11 |
| Reduction in proptosis (mm) | ||
| Fat only | 1.8 to 4.7 | 10 |
| Bony walls | 3.2 to 7.4 | 1, 10, 12 |
| Rate of new diplopia (%) | 0 to 64 | 10 |
| Quality of Life | ||
| GO-QOL scale | ||
| Vision-related mean change score (0-100) | 8 | 8 |
| Appearance-related mean change score (0-100) | 19.5 | 8 |
| SNOT-22 questionnaire | ||
| Total mean change score (0-110) | -13.7 | 19 |
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