Analysis of the efficacy of transnasal endoscopic annulus of zinn area decompression in the treatment of dysthyroid optic neuropathy

Abstract

Objective: To evaluate the early efficacy and safety of transnasal endoscopic decompression in the annulus of zinn (AZ) region for refractory dysthyroid optic neuropathy (DON) and to preliminarily analyze the correlated factors of postoperative visual function outcome. Methods: From July 2021 to January 2023, 35 patients (56 eyes) with DON who received AZ area decompression in Peking University Third Hospital were included retrospectively, including 9 males (13 eyes) and 26 females (43 eyes), aging (52.2±12.0) years. Among them, 35 eyes underwent two-wall (medial and inferior) orbital decompression using an endonasal endoscopic approach, while 21 eyes received three-wall (medial, lateral, and inferior) orbital decompression through a combined approach. Key parameters such as best corrected visual acuity (BCVA), visual field (MD value), eyeball prominence, intraocular pressure, and complications were recorded. Postoperative data were collected one month after surgery. The statistical analysis was performed using paired t-test and Spearman correlation analysis. Results: Significant outcomes were observed post surgery in BCVA, visual field, intraocular pressure and proptosis (t value was 8.37, 6.17, 4.50, and 9.20, respectively, all P<0.001). The reduction in proptosis was statistically significant between the 2-wall and 3-wall orbital decompression groups (t=-2.82, P=0.007). Changes in BCVA, visual field, and intraocular pressure before and after surgery was greater in the 3-wall orbital decompression group compared to 2-wall orbital decompression group, although the difference was not statistically significant (all P>0.05). Change in postoperative visual acuity and visual field was significantly positively correlated with preoperative visual acuity and preoperative visual field (all P<0.001). Similarly, change in intraocular pressure and proptosis was positively correlated with preoperative intraocular pressure and preoperative protrusion (all P<0.001). Preoperative diplopia was reported in seven patients (20.0%), and two new cases (5.7%) were noted post-operation, which resolved within 3 months after surgery. Conclusions: Endoscopic endonasal decompression of the AZ area is a safe and effective surgical treatment for DON, with notable improvements in BCVA. Furthermore, three-orbital wall decompression seems to yield better outcomes in terms of eye retraction.