Predictors of Success Following Müller's Muscle-Conjunctival Resection.

[PURPOSE] This study aims to describe Müller's muscle-conjunctival resection surgery in terms of outcomes and potential factors that may predict final positions.

[METHODS] This cross-sectional cohort study included patients undergoing Müller's muscle-conjunctival resection surgery for involutional ptosis over a 15-year period. Success was defined in 2 ways: 1) final marginal reflex distance 1 (MRD1) ≥2.5 mm (MRD1 success) and 2) final difference in MRD1 ≤1 mm between eyelids (symmetry success). Percentages of patients achieving both outcomes were calculated. Predictors of outcome were assessed using bivariate analysis and multivariate models.

[RESULTS] The final sample included 315 eyes in 192 patients. The mean age (standard deviation) was 67.9 (11.9) years, and 60.0% were female. MRD1 ≥2.5 mm was achieved in 65.7% of the sample. Symmetry within 1 mm was achieved in 82.9% of the sample. Significant (p < 0.05) predictors of MRD1 success were female sex, concurrent lower eyelid blepharoplasty, and higher preoperative MRD1 in bivariate analysis; preoperative MRD1 and female sex in the multivariate model; and preoperative MRD1 in the a priori model. Significant (p < 0.05) predictors of symmetry success were female sex, previous lower eyelid blepharoplasty, concurrent lateral canthoplasty, preoperative symmetry, and older age in bivariate analysis; only female sex in the multivariate model.

[DISCUSSION] Müller's muscle-conjunctival resection is effective for elevating the eyelid in ptosis and may be more effective for achieving symmetry than absolute elevation over 2.5 mm. The results remain difficult to predict based clinical, surgical, or demographic factors.