Reduction of diplopia following endoscopic orbital decompression: the orbital sling technique.

OBJECTIVE: Although endoscopic orbital decompression has become the surgical treatment of choice for patients with proptosis from Graves disease, postoperative diplopia requiring corrective eye muscle surgery can occur in up to 63% of patients. The purpose of the study was to evaluate a new technique intended to reduce the incidence of diplopia following endoscopic orbital decompression. STUDY
DESIGN: Case-control.
METHODS: Endoscopic orbital decompression was performed on 58 orbits in 37 patients with proptosis from Graves disease. The orbital sling technique, which makes use of a horizontal strip of periorbital fascia to prevent prolapse of the medial rectus muscle, was used on 20 orbits in 13 patients. Conventional endoscopic decompression was performed in 24 control subjects. The mean duration of follow-up was 3.3 +/- 1.3 years (range, 1.7-5.1 y).
RESULTS: The incidence of new-onset or worsened diplopia following endoscopic decompression was significantly lower for the orbital sling group compared with control subjects (0% vs. 29.2%, respectively [ =.038]). No patients in the orbital sling group developed new-onset diplopia following surgery. Of the eight patients with pre-existing diplopia from the orbitopathy, double vision improved in four patients (50%) and was unchanged in the remaining four patients (50%). The mean reduction in proptosis was comparable for the orbital sling and control groups (5.1 +/- 1.1 mm vs. 5.0 +/- 1.9 mm, respectively [ P=.98]). CONCLUSIONS The preservation of a fascial sling overlying the medial rectus muscle during endoscopic orbital decompression appears to reduce the incidence of postoperative diplopia, while still allowing for a satisfactory reduction in proptosis. This modification of the standard decompression technique should be considered for the treatment of patients with proptosis.