Plane of Fat Redistribution and Infraorbital Nerve Protection in Tear Trough Surgery
Plane of Fat Redistribution
After complete release of the tear trough (orbicularis-retaining) ligament, fat is redistributed in the supraperiosteal plane, positioned above the periosteum but below the orbicularis oculi muscle. 1, 2
Technical Details of Fat Placement
The supraperiosteal pocket is created below the orbicularis oculi muscle using blunt scissor dissection after the arcus marginalis is released. 1
Fat pedicles are transposed and anchored across the orbital rim with 5-0 polyglactin sutures, securing both the orbital fat and orbital septum in the supraperiosteal space. 1
An alternative technique places fat above the orbicularis muscle (rather than below it in the supraperiosteal plane), which has shown comparable long-term results with no major complications and may simplify the dissection. 2
Anatomical Rationale
The orbicularis retaining ligament consists of two layers: the upper layer originates from the orbital margin medially and from preorbital walls laterally, while the lower layer originates from preorbital walls and passes through the orbicularis muscle and superficial fat before ending at the skin. 3
Complete release of this ligament eliminates the tethering effect that creates the tear trough deformity, allowing fat redistribution to fill the hollow concavity. 4
The tear trough measures approximately 16.56 mm in length, with width varying from 2.06 mm at the inner canthus to 3.25 mm at the lateral alar margin. 3
Protection of the Infraorbital Nerve
The infraorbital nerve is protected by maintaining dissection in the supraperiosteal plane and avoiding deep penetration beyond the orbital rim during pocket creation.
Specific Technical Safeguards
Limit dissection depth: The supraperiosteal pocket should be created with blunt scissor dissection, staying superficial to the periosteum where the infraorbital nerve exits its foramen approximately 6-8 mm below the orbital rim. 1
Controlled arcus marginalis release: Release the arcus marginalis using cautery cutting rather than sharp dissection to maintain precise control and avoid deep penetration that could injure the nerve. 1
Avoid lateral extension: The dissection should not extend excessively lateral or inferior to the planned fat repositioning area, as the infraorbital nerve courses obliquely across the maxilla after exiting its foramen. 1
Use preseptal approach: Performing preseptal dissection (rather than postseptal) and extending over the arcus marginalis provides a safer plane that keeps the surgeon away from deeper neurovascular structures. 1
Clinical Outcomes and Safety Profile
In a prospective study of 20 young Asian patients, no major complications including nerve injury, lower eyelid retraction, ectropion, or diplopia were observed using the supraperiosteal technique. 1
A larger series of 105 patients with mean 31-month follow-up showed effective tear trough correction with no compromise of tarsoligamentous support and no ectropion development in any patient. 4
The supramuscular fat placement technique (above rather than below the orbicularis) demonstrated no contour irregularities or significant long-term complications in 41 patients followed for minimum 44 months. 2
Common Pitfall to Avoid
The critical error is creating the pocket too deep (subperiosteal rather than supraperiosteal) or extending dissection too far inferiorly, which places the infraorbital nerve at direct risk of injury from instruments or suture placement. 1 Maintaining blunt dissection in the correct anatomical plane and limiting the extent of pocket creation to the immediate suborbital region minimizes this risk.