Association of the Preoperative Fat-to-ratio on the Outcome of Endoscopic Orbital Decompression

Purpose: To investigate the association of the preoperative fat-to-orbit ratio on the outcome of endoscopic orbital decompression in patients with thyroid-associated orbitopathy (TAO).Methods: Between January 2021 and December 2022, 36 patients with TAO, 72 eyes in total, underwent endoscopic orbital decompression at our hospital’s ophthalmology department. We calculated fat-to-orbit ratios using two-dimensional facial computed tomography scans, and conducted both preoperative and postoperative measurements of proptosis and the prism cover test. We used binominal logistic regression analysis to examine the correlation between the ratios and postoperative complications (diplopia, strabismus, lid retraction) following the surgery. Furthermore, simple linear regression analysis was used to assess the relationship between the ratios and change in exophthalmos.Results: The regression indicated significant associations between the ratio and the onset of postoperative complications such as new-onset postoperative diplopia (NOPD) (β = -0.098, p = 0.029), postoperative strabismus (β = -0.123, p = 0.009), and eyelid retraction (β = -0.188, p = 0.002), particularly in cases requiring subsequent strabismus or eyelid retraction surgery after the initial procedure.Conclusions: The preoperative fat-to-orbit ratio is a significant predictor of postoperative complications such as NOPD, strabismus surgery and eyelid retraction surgery in patients undergoing endoscopic orbital decompression for thyroid eye disease. Therefore, it should be considered a valuable indicator of surgical outcomes and complications in such patients.