Revisiting upper eyelid anatomy: introduction of the septal extension.

BACKGROUND: The current trend in plastic surgery of the eyelid has taken on increased dependence on anatomical considerations in the marriage of aesthetic and functional ideals. Often, the plastic surgeon performs ptosis and/or septal surgery in conjunction with blepharoplasty. The relationship between eyelid adnexal structures and upper eyelid function is a delicate but critical one. Current anatomical description states that the septum does not reach the superior tarsal border and inserts at a variable level on the levator aponeurosis. Conflicting observations in clinical practice stimulated this study to delineate the septal relationship to surrounding structures. In addition, this study may help to explain the increased rate of recurrence in ptosis repairs that incorporate plication techniques. METHODS: Dissection of four fresh cadaveric upper lid specimens in situ along with hematoxylin and eosin and trichrome stains of harvested eyelid tissue were used to redefine septal anatomy. Clinical case correlations are made to illustrate the significance of the histologic findings. RESULTS: A distinct septal extension was demonstrated arising from the orbital septum and covering preaponeurotic fat and tarsus completely. Histology of the anterior lamellae confirmed the presence of this thin fibrous sheet. In vivo assessment of this structure verifies its dynamic role in upper lid function. The clinical ramifications of this anatomical nuance are realized. CONCLUSIONS: A septal extension to the ciliary margin of the upper eyelid is established. Suture plication of the septal extension can induce lid elevation, with potential postoperative lid retraction. Intraoperative failure to recognize and distinguish this extension from the aponeurosis proper may lead to the high reported rates of unsuccessful ptosis correction. This refinement of septal anatomy should increase precision and help surgeons avoid complications in advanced blepharoplasty and ptosis surgery.