Authors: Victoria Leung, Jessica El Khazen Dupuis, Davin C. Ashraf, Oluwatobi O. Idowu, M Reza Vagefi, Robert C. Kersten, Erika Massicotte, Evan Kalin-Hajdu. 

Author Disclosure Block: V. Leung: None. J. El Khazen Dupuis: None. D.C. Ashraf: None. O.O. Idowu: None. M. Vagefi: None. R.C. Kersten: None. E. Massicotte: None. E. Kalin-Hajdu: None.

Abstract Body:

Purpose: To prospectively report the success rates of Muller’s muscle conjunctival resection (MMCR) surgery in a large cohort of patients
Study Design: Prospective interventional study
Methods: Patients undergoing unilateral or bilateral MMCR were consecutively enrolled from the Departments of Ophthalmology at the University of California, San Francisco, and the Université de Montréal from 2015-2020. Patients undergoing concomitant eyelid surgeries were excluded. Pre-operative data included (but was not limited to) age, sex, race, previous surgery, and ptosis etiology. Intraoperative data included (but was not limited to) the amount of resected tissue (mm) and unexpected events (hematoma/suture transection/reclamping). Post-operative complications (erosions, etc.) were recorded. Post-operative visits 1 and 2 (PO1; PO2) occurred 1 week and 3 months after surgery. Marginal reflex distance-1 (MRD1) was recorded at the preoperative visit prior to phenylephrine (MRD1-prephenyl), at the preoperative visit following phenylephrine (MRD1-postphenyl), immediately following surgery (MRD1-IO), at PO1 (MRD1-PO1) and PO2 (MRD1-PO2). MRD1 success of an operated eyelid was defined as MRD1PO2 >/=2.5mm. Symmetry success per patient (unilateral and bilateral surgeries) was defined as an interlid MRD1PO2 difference </=1mm. Total success of an operated eyelid was defined as MRD1PO2 >/=2.5mm of the operated eyelid and an interlid MRD1PO2 </=1mm.
Results: 158 patients were enrolled and a total of 235 eyelids underwent MMCR. 81 patients underwent unilateral surgery and 77 bilateral surgery. 134 patients (203 eyelids) had PO2 results. 71% were female, 73% were Caucasian, the mean patient age was 67 years, and 9% of eyelids had undergone previous eyelid surgeries. Involutional ptosis (86%) was the most common cause of ptosis. Among operated eyelids, the mean MRD1-prephenyl was 0.72mm, MRD1-postphenyl 2.91mm, MRD1-IO 2.98mm, MRD1-PO1 2.82mm and MRD1-PO2 was 3.07mm. The mean amount of resected tissue was 9.46mm and 11% of eyelids had an intraoperative unexpected event. <1% had a post-operative complication and 3% required post-operative adjustments to lower/raise the eyelid. 78% of operated eyelids achieved MRD1 success, 79% of patients achieved symmetry success, and 68% of patients achieved total success (MRD1 in the operated eyelid >/=2.5mm and symmetry within 1mm).
Conclusions: MMCR is effective at elevating a ptotic upper eyelid and at obtaining post-operative symmetry. Prior publications have reported each as independent measures of success. However, when considering total success as a combination of both elevation and symmetry, surgical success is likely less than the rates previously reported in retrospective studies. Future work will explore predictors of surgical success in order to improve the selection of surgical candidates for MMCR.