Surgical Mechanism of Suspension of the Eyelid to the Check Ligament of the Superior Fornix for Blepharoptosis: An Anatomical Study.

Suspension of the eyelid to the check ligament of the superior fornix for blepharoptosis correction was first reported by Holmström in 2002, yet its exact surgical mechanism remains controversial, with core debates focusing on whether the suspension force originates from static or dynamic sources. In this study, twenty eyes from 10 fresh Chinese adult cadavers were used to establish the blepharoptosis models and simulate the suspension surgery. We observed and measured the eyelid lift heights (ELHs) under three different conditions (physiological condition, ptosis model, after simulated surgery) following manual posterior traction of the levator palpebrae superioris or superior rectus muscle. Under the above conditions, the results from pulling the rectus were 2.58 ± 1.03 mm, 1.90 ± 0.84 mm, and 3.75 ± 1.10 mm, and from pulling the levator were 7.95 ± 1.10 mm, 2.13 ± 0.80 mm, and 7.78 ± 1.37 mm. Notably, the initial positions of the eyelids were raised by 1.93 ± 0.90 mm after the simulated surgery. The ELHs could be increased by pulling these muscles, respectively, but the ELH was obviously higher by pulling the levator than the rectus. We speculated that the postoperative driving force of the eyelid lift behind the suspension surgery comprised static suspension force from the check ligament and dynamic contraction force from the levator and rectus together and levator seems to play more important role. Based on this synergistic mechanism, we propose a hypothesis-generating clinical decision-making algorithm tailored to preoperative levator function levels.No Level Assigned This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors https://link.springer.com/journal/00266 .