Proximal tarsal attachments of the levator aponeurosis: implications for blepharoptosis repair

Abstract

Purpose: To examine the tarsal attachments of the levator aponeurosis.

Design: Experimental anatomic study.

Participants: Sixteen orbits from 12 fresh frozen white cadavers.

Methods: Eight specimens served as controls. In the remaining 8 specimens from 4 cadavers, the upper eyelid was everted. All specimens then were fixed in formalin. The age, sex, and laterality were recorded in both groups. The eyelid lamellae and tarsal attachments of the levator aponeurosis in particular were examined microscopically. Lamellar and nonlamellar ocular anatomic features and the relationships of the preaponeurotic and postaponeurotic spaces were measured.

Main outcome measures: Histologic findings of the extent and pattern of the tarsal attachments of the levator aponeurosis in relation to the tarsus and Müller's muscle and of the changes in the lamellae in eyelid eversion.

Results: The demographic and baseline anatomic characteristics of both the noneverted control and everted eyelid groups were similar. In comparing everted with noneverted controls, the preaponeurotic space was significantly shorter (6.22 and 10.61 mm, respectively; P = 0.003) and the preaponeurotic-to-postaponeurotic space ratio was halved (0.57 and 1.16, respectively; P = 0.005). Although the distance from the superior tarsal border to Whitnall's ligament increased significantly in everted versus noneverted eyes (14.65 and 11. 03 mm, respectively; P = 0.016), there was no significant difference in the length of postaponeurotic space in the 2 groups (11.07 and 9.69 mm, respectively; P = 0.370). The levator aponeurosis attached to the anterior tarsus in both groups. The proximal point of attachment was the superior border of the tarsal plate, adjacent to the insertion of Müller's muscle tendon.

Conclusions: The deeper aponeurotic fibers and Müller's muscle attach proximally at the superior tarsal border. Upon eyelid eversion, the 2 lamellae move as a unit and the postaponeurotic space remains stable. A proximal tarsal attachment suggests that blepharoptosis procedures that advance an involutional or disinserted levator aponeurosis onto to the superior tarsus approximate that aspect of native anatomic features. In addition, posterior surgical approaches that address Müller's muscle may involve resections in closer proximity to the aponeurosis than previously thought.

Financial disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.