Endoscopic Orbital Decompression

Endoscopic orbital decompression was developed soon after the advent of endoscopic sinus surgery. The technique was first described by Kennedy et al. in 1990 and Michel et al. in 1991 and has gained popularity over the past several decades, now representing about a quarter of orbital decompressions performed in the United States annually. The major advantages of the endoscopic approach include avoidance of an external facial incision and resultant scar, as well as improved visualization of key anatomic structures, particularly in the region of the orbital apex, a critical area of decompression in patients with optic neuropathy.

The major disadvantage of the procedure is coordination between an oculoplastic surgeon and an otolaryngologist and potential longer total operative time. Although no significant difference in cost of the procedure was observed with bivariate analysis, the need for coordination may contribute to the finding that the majority of oculoplastic surgeons surveyed perform the surgery alone via an external approach.

Graves orbitopathy occurs in up to half of patients with Graves disease and is the most common indication for endoscopic orbital decompression. Graves orbitopathy can be associated with visual deficits from optic neuropathy and diplopia. In patients with Graves disease, proptosis and exposure keratopathy are frequent indications for surgery. Graves orbitopathy, also known as thyroid eye disease (TED), is characterized by an initial acute inflammatory phase followed by a chronic, fibrotic phase. Typically decompression is performed in the chronic phase of TED; however, severe symptoms with optic neuropathy during the acute phase may warrant immediate treatment. Other indications for orbital decompression techniques include access for drainage of orbital hematoma or subperiosteal abscess, resection of orbital and intracranial pathology, and transnasal endoscopic intraorbital ligation of the anterior ethmoid artery.

Postoperatively patients undergoing endoscopic orbital decompression for TED reported significantly improved mean scores for the 22-item Sinonasal Outcomes Test from preoperative baseline after 1 year. When a Hertel exophthalmometer (Good-Lite, Elgin, IL) was used, a 3.2-mm reduction in proptosis was observed in patients with medial endoscopic decompression alone, with the addition of an external lateral decompression resulting in an additional 2.4-mm reduction in proptosis. Several studies have used preoperative and postoperative computed tomography imaging to quantitatively assess volume change after decompression. In one study of seven patients, an average increase in volume was 7.3 cm ³ in patients for whom medial and inferior orbital wall decompression was performed while maintaining an inferomedial strut. Another study, in which only medial decompression was performed, found an average increase in 6.08 cm ³ in volume on postoperative imaging of 12 patients.