Delayed improvement in Muller’s muscle ptosis surgery

1 December 2018 | James Hsuan | EYE - Oculoplastic, EYE - Orbit

This is a retrospective review of patients undergoing ptosis surgery. The authors had noticed anecdotally that although a posterior approach Muller’s muscle and conjunctival resection (MMCR) appeared to achieve similar results to an anterior approach levator resection (ALR) in the long-term, the former group appeared to have less lid elevation in the early postoperative period. They therefore compared 68 eyes undergoing MMCR with 46 undergoing ALR. They measured the upper lid margin reflex distance (MRD1) by analysing digital photographs taken preoperatively, at one week postoperatively and finally between three and 12 months after surgery. In the MMCR group, they found a significant increase in the MRD1 comparing the preoperative and the early postoperative measurements, and also between the early and late postoperative measurements. However in the ALR group, there was a greater difference between the preoperative and early postoperative MRD1s, but no significant difference between early and late measurements. There was no significant difference comparing the two groups with each other at either the preoperative or the late stages. The authors therefore confirmed their suspicions that the MMCR group took longer to reach their final height, and over a third of this group had less than 0.5mm increase in MRD1 at one week after surgery. They surmise that the MMCR procedure may not be simply a posterior approach plication of the levator aponeurosis, but that it may work through a different mechanism. Confusing the picture in this study was the technique used for the ALR surgery, which included a Muller’s muscle plication, as Muller’s was dissected from the conjunctiva and advanced with the aponeurosis. In their defence they argue that even if the aponeurosis is dissected from Muller’s, there is always some trauma or resection of Muller’s muscle when the aponeurosis is advanced. They conclude that neither operation works purely on a single tissue, but despite this there remains evidence that the two operations achieve their results by different mechanisms.