Combined endonasal and orbital approach for annulus of Zinn area decompression in dysthyroid optic neuropathy

Background: Dysthyroid optic neuropathy (DON) is a serious complication of thyroid-associated ophthalmopathy (TAO) that can cause permanent vision loss from orbital apex syndrome. Urgent management of high-dose corticosteroid pulse therapy is recommended, and salvage orbital apex decompression surgery may require in refractory patients ineffective with corticosteroid pulse therapy. Purpose: To evaluate the short-term efficacy and safety of combined endoscopic endonasal and orbital approach decompression in the annulus of the Zinn (AZ) area in refractory dysthyroid optic neuropathy (DON). Methods: In this retrospective study, patients who underwent combined endoscopic endonasal and orbital approach decompression around the AZ area for the treatment of refractory DON from May 2021 to March 2022 were enrolled. A total of 15 orbital apex were decompressed across 9 patients. The demographic, imaging, and surgical data, as well as preoperative and postoperative best corrected visual acuity (BCVA), proptosis degree and Modified-Chinese-TAO-QOL scores, were collected and assessed. The t-test was used to identify differences between preoperative and postoperative parameters: visual acuity, proptosis and QOL scores. Results: The mean best corrected visual acuity (BCVA) improved from 0.79 +/- 0.77 LogMAR preoperatively to 0.21 +/- 0.27 LogMAR (P < 0.001) postoperatively. Additionally, proptosis decreased from 22.25 +/- 2.01 mm to 18.42 +/- 1.85 mm (P < 0.01), with an average decrease of 3.7 mm. The preoperative scores of the visual, psychological, and comprehensive components of QoL were 14.60 +/- 9.08, 37.49 +/- 6.26 and 26.75 +/- 3.70, respectively, which significantly improved postoperatively to 54.18 +/- 7.23, 68.78 +/- 12.53 and 61.88 +/- 9.37, respectively. The postoperative follow-up time ranged from 2 to 11 months, and the median follow-up time was 7 months. There was 1 case of transient postoperative sinusitis and 1 new case of transient diplopia, which was relieved after 3 months. Conclusion: Combined endoscopic endonasal and orbital approach adequate decompression for AZ area significantly improves visual acuity and QOL in patients with DON.