Orbital Decompression in the Endoscopic Age: The Modified Inferomedial Orbital Strut

Objective Postoperative diplopia occurs in up to 45% of patients following orbital decompression for exophthalmos associated with Graves' orbitopathy. We sought to describe outcomes of our balanced orbital decompression strategy that includes the preservation of a modified inferomedial orbital strut (mIOS). Study Design Case series with chart review. Setting Academic medical center. Subjects and Methods A total of 115 consecutive orbital decompressions were performed on 73 patients (42 bilateral) with Graves' orbitopathy. All patients underwent (1) a balanced decompression technique incorporating an endoscopic medial and external lateral decompression and (2) a mIOS technique with preservation of the anterior half of the inferomedial orbital strut. A periorbital periosteal (orbital) sling was utilized in patients (n = 54) without threatened vision loss, proptosis >28 mm, or periorbital disruption to prevent prolapse of the medial rectus muscle. Results Utilization of the mIOS technique with or without a sling did not adversely affect the reduction in proptosis (5.1 mm with sling vs 5.0 mm without sling; P = .85).The incidence of new-onset postoperative diplopia was 17% (n = 6). The sling was not associated with postoperative diplopia (odds ratio = 0.54, 95% confidence interval: 0.08-3.40, P = .51), while it was associated with resolution of preexisting diplopia (odds ratio = 6.67, 95% confidence interval: 1.06-42.06, P = .04). No intraoperative complications occurred, and no patients suffered a decrement in visual acuity. Conclusion Balanced orbital decompression utilizing a mIOS in patients with Graves' orbitopathy provides a safe and effective reduction in proptosis with a low rate of new-onset diplopia as compared with historical values. Utilization of an orbital sling may be beneficial in reducing postoperative diplopia in select patients.