Graded Eyelid Crease Approach to the Superior Orbital Apex: An Anatomical Study

To describe a graded eyelid crease approach to access the superior orbital apex, and to quantify the working space enabled with the sequential release of structures along the superior orbital rim.

Cadaveric dissection study of 7 cadaver heads (14 orbits). This technique involved a subperiosteal approach to the superior orbital apex. This was performed by sequential dissection from 1) the supraorbital neurovascular bundle (SNB) to the zygomaticofrontal suture, 2) extension of this plane to the Whitnall's tubercle, 3a) dissection around the SNB up to the trochlea while preserving the SNB, or 3b) release and division of the SNB, and finally 4) subperiosteal release of the trochlea. Measurements were taken between each landmark (mean ± 1 SD). With each step, a silicone mold was created of the subperiosteal cavity with maximal orbital retraction, which was maintained within 10 mm from the superior orbital rim. The length (mm), width (mm), height (mm), and weight (g) of the mold were quantified.

The mean distance from SNB to the zygomaticofrontal suture is 27.0 ± 2.9 mm; zygomaticofrontal suture to Whitnall's tubercle 8.9 ± 3.1 mm, and SNB to trochlea 4.6 ± 2.7 mm. There was a linear increase in the length, width, and height of the silicone mold with each progressive step. The largest gains in height and weight of the silicone mold were noted progressing from step 2 to 3a.

Quantitative analysis of the transorbital approach to the superior orbital apex demonstrates that dissection around the SNB provides a wider surgical corridor of access.