To determine incidence of new-onset diplopia, resolution of preexisting diplopia, and impact on proptosis resulting from endoscopic orbital decompression with and without preservation of the inferomedial orbital strut for thyroid orbitopathy.
Retrospective review of all patients undergoing endoscopic 2- or 3-wall decompression with or without preservation of the strut for thyroid orbitopathy from January 2012 to June 2015.
Twenty-six patients (45 orbits) were included and divided into 4 primary categories: 2-wall decompression with strut preservation (4 orbits, 8%), 2-wall decompression with strut removal (7 orbits, 16%), 3-wall decompression with strut preservation (27 orbits, 60%), and 3-wall decompression with strut removal (7 orbits, 16%). The incidence of new-onset diplopia was 20% (2/10 patients without preoperative diplopia) overall and 16% in the strut preservation group (1/6 patients without preoperative diplopia). Resolution of diplopia occurred in 4 of 16 patients (25%) with preoperative diplopia, and all 4 had been treated with a 3-wall decompression with strut preservation. Resolution of diplopia in the group treated with strut preservation was 36% (4/11 patients with preoperative diplopia), and 0% of the 5 diplopic patients treated without strut preservation. Reduction in proptosis was statistically greater in those treated with strut removal (p = 0.003).
This study demonstrates that endoscopic orbital decompression with preservation of the inferomedial bone strut results in a comparable to lower rate of new-onset diplopia compared with other reported techniques. When combined with 3-wall balanced decompression, this technique demonstrates a high rate of resolution of preexisting diplopia.