Rehabilitative orbital decompression for Graves' orbitopathy: risk factors influencing the new onset of diplopia in primary gaze, outcome, and patients' satisfaction.

BACKGROUND Patients with moderate to severe Graves' orbitopathy (GO) rather frequently require rehabilitative surgery after medical therapy. Diplopia is the most common side effect of orbital decompression (OD). The aim of this study was to evaluate the occurrence of postoperative diplopia in primary gaze after OD, and the influence of the surgical approach on this outcome. Moreover, we investigated the results in terms of proptosis reduction, and the long-term subjective satisfaction of patients treated with OD with regard to their appearance and ocular function. METHODS A retrospective evaluation of 247 patients with GO treated with medial and lateral decompression (MLD) or lateral decompression (LD) OD between January 2002 and December 2009 was performed. RESULTS The overall prevalence of postoperative diplopia in primary gaze was 55/247 (22.3%), with a statistically significant difference (p<0.001) between patients with (36/113, 31.2%) and those without (19/134, 14.2%) preoperative diplopia in secondary gaze. The surgical procedure influenced the outcome in patients without preoperative diplopia (17.8% after MLD and 0% after LD, p=0.02), but not in patients with preoperative diplopia in secondary gaze (33.3% after MLD and 26.1% after LD, p=0.5). Overall, proptosis reduction was 5.7±2.2 mm (1-11 mm), after MLD and 4.0±1.6 mm (1-8 mm) after LD (p<0.001). Fifty-one out of 55 patients with constant, postoperative diplopia in primary gaze after OD underwent squint surgery, which was successful in all but two. Four patients refused squint surgery. Patients were also interviewed for satisfaction in terms of recovery of their appearance and ocular function after a mean of 6 years from surgery (range 2-9 years): more than 85% of patients reported a good to excellent postoperative satisfaction for both items. CONCLUSIONS Preoperative diplopia in secondary gaze is a risk factor for the development of diplopia in primary gaze after OD, independently of the surgical approach (MLD vs. LD). In absence of diplopia, MLD, but not LD, seems to be associated with its development in primary gaze. The reduction in proptosis after MLD is greater than that after LD. Most patients were satisfied with the results of both appearance and ocular function after OD.