The role of Whitnall's ligament position in the success of levator resection surgery in congenital ptosis

Purpose This study aimed to investigate the role of Whitnall's ligament position in the success of levator resection surgery in congenital ptosis. Methods It was an interventional case series on patients with congenital ptosis who underwent levator muscle resection in Farabi Eye Hospital (2020-2022). Patients with incomplete follow-up, a history of trauma, poor Bell's phenomenon, previous ocular and lid surgeries, poor levator function (<= 4mm), and syndromic ptosis or systemic diseases were excluded. During the surgery, several factors, including the distance between Whitnall's ligament and the upper edge of the tarsus (W-distance), the vertical length of the tarsus (T-length), and the amount of levator muscle resection (LMR), were measured. A successful outcome was defined as the inter-eye difference of margin reflex distance-1 (MRD1) <= 1 and post-op MRD1 >= 3 OR the inter-eye difference of MRD1 <= 0.5 with any value of post-op MRD1 in unilateral cases and Postop-MRD1 > 3 in bilateral cases during the 3-months period.Results Thirty four eyes of 34 patients were included, and 79.4% of patients achieved successful outcomes. In univariate analysis, Preop-MRD1 and Preop-LF had meaningful negative correlations with the amount of LMR to reach the successful outcome (p < 0.05), which was only meaningful for Preop-LF in multivariable analysis (p < 0.05). Noticeably, W-distance had a significant positive correlation in univariate and multivariable linear regression (p < 0.05).Conclusions W-distance can be considered a significant new parameter other than Preop-LF influencing the amount of levator resection needed to achieve success in levator resection surgery.