Significance of Early Postoperative Eyelid Position on Late Postoperative Result in Mueller's Muscle Conjunctival Resection and External Levator Advancement Surgery.

Abstract

The purpose of this study was to determine whether advancement of the levator aponeurosis in external levator resection surgery or Mueller's muscle and conjunctiva in Mueller's muscle conjunctival resection (MMCR) surgery has a differential effect on variation in eyelid position during the postoperative period. In this retrospective observational cohort study, 2 groups of patients were defined. The first underwent MMCR surgery without tarsectomy by surgeon 1. The second underwent external levator resection without dissection posterior to the levator aponeurosis by surgeon 2. Marginal reflex distance (MRD1) was calculated based on digital photographs at baseline, 1 week postoperatively and at 3-month follow up. The primary outcome measure was change in MRD1 over time. The secondary outcome was defined as the proportion of patients with minimal early postoperative change (change of MRD1 less than 0.5 mm at 1 week postoperatively). Repeated measures analysis of variance, t test, and chi-square analyses were performed. Of the 114 eyes in the sample, there were 68 in the MMCR group and 46 in the external levator resection group. A significant interaction between group and time was noted (p < 0.05), indicating change in MRD1 over time was different between the groups. Bonferroni corrected multiple comparisons yielded significant differences between each time point for MMCR surgery (p < 0.01). No difference in MRD1 was noted for the external levator resection group from the early to late postoperative visit. Comparing each time point across groups revealed significantly lower MRD1 for the MMCR group at the early postoperative visit (p < 0.01). Preoperative and late postoperative MRD1 did not significantly differ between the groups. Regarding the secondary outcome, patients undergoing MMCR surgery were 3.7× as likely to demonstrate <0.5 mm of change in MRD1 at week 1 (p < 0.05). When considering the 39.7% (n = 27) MMCR patients in this category, 59.3% (n = 16) went on to show an MRD1 increase >1 mm from the early postoperative to the late postoperative time points. Both external levator resection and MMCR can effectively elevate the eyelid in cases of primary involutional ptosis, and have similar late postoperative results. The authors found that MMCR cases undergo greater change between the early and late postoperative period, suggesting the process of eyelid elevation after MMCR may be dynamic, involving postoperative physiologic modification.