Levator Muscle Complex Exploration During Surgery for Simple Severe Congenital Ptosis

To describe the gross morphology of the levator palpebrae superioris (LPS) muscle complex in severe congenital ptosis with poor levator function (LF) and to evaluate the surgical outcomes when levator surgery was performed based on intraoperative factors.

This is a retrospective, interventional case series that includes children having simple severe congenital ptosis with LF ≤ 4 mm for whom levator muscle surgery was performed rather than preplanned frontalis suspension based on the intraoperative LPS muscle evaluation. The collected data included: demographics; ptosis measurements, including margin reflex distance 1 and LF; morphological appearance of LPS muscle and its aponeurosis (levator aponeurosis); surgical technique, and outcomes. Fatty infiltration of the LPS muscle belly was graded, based on its ratio to the muscle's normal width, as minimal (<5%), mild (5-25%), moderate (25-50%), or severe (>50%).

A total of 109 eyelids met the inclusion criteria. Levator aponeurosis, distal and proximal (orbital) zones of the LPS muscle belly were evaluated. Levator aponeurosis was thin in 56.9% of the eyelids and thick with dense fibrotic changes in 43.1%. The distal zone showed extensive fatty infiltration and abnormal blood vessels in all eyelids. The proximal zone appeared fleshy red with minimal to moderate fatty infiltration in about three-fourths of the eyelids (n = 78, 71.6%). Securing this proximal zone to the tarsal plate resulted in a significant improvement in margin reflex distance 1 and LF (median, 4.0 mm and 7.0 mm, respectively, p < 0.001) during a median follow-up period of 8 months (range, 6-96 months).

Intraoperative assessment of the LPS muscle complex, rather than preoperative LF, resulted in a change in surgical planning from frontalis suspension to a levator-based surgery with surgical success.