What is the incidence of fat entrapment after lower‑lid blepharoplasty with fat transposition, and how can it be completely prevented?

Fat Entrapment in Lower Lid Blepharoplasty: Incidence and Prevention

Incidence of Fat Entrapment

Fat entrapment causing restrictive strabismus after lower lid blepharoplasty is a rare but serious complication, though specific incidence rates are not well-established in the literature. 1, 2

The available evidence indicates:

• The incidence of strabismus after eyelid surgery is estimated at under 3% (three cases in 920 procedures), making it much lower than complications associated with other ophthalmic surgeries 1
• Fat adherence and scarring in adjacent tissue have been implicated as mechanisms for new-onset diplopia after lower lid blepharoplasty, sometimes due to damage to the inferior rectus muscle 1
• When fat entrapment does occur, it can lead to restrictive strabismus through inadvertent entrapment or adhesion of orbital fat to extraocular muscles 2

Complete Prevention Strategies

Complete avoidance of fat entrapment cannot be guaranteed, but meticulous surgical technique significantly minimizes risk. The following technical approaches reduce the likelihood of this complication:

Surgical Approach Selection

• Consider transconjunctival approaches over transcutaneous approaches when performing fat repositioning, as these avoid disruption of the orbital septum and reduce scarring near the inferior rectus 3, 4
• Transconjunctival blepharoplasty with fat transposition above the orbicularis muscle has demonstrated no major complications in long-term follow-up studies 3

Intraoperative Technical Considerations

• Avoid excessive cautery, which increases the risk of scarring and tissue adherence to extraocular muscles 1
• Minimize hemorrhage through careful hemostasis, as postoperative bleeding contributes to scarring and fat adherence 1
• Maintain precise dissection planes to avoid misdirected dissection that can damage the inferior rectus or create pathways for fat entrapment 1
• When repositioning fat, secure it in anatomically appropriate planes (supraperiosteal, submuscular, or above orbicularis) rather than allowing free migration 3, 4

Fat Management Techniques

• Use controlled fat repositioning with internal fixation methods rather than allowing uncontrolled fat placement 4
• Consider segmental fat grafting techniques that provide more controlled placement and blending of the lid-cheek junction 5
• Avoid aggressive fat removal that might necessitate revision procedures requiring additional manipulation near extraocular muscles 5

Anesthesia Considerations

• Use topical anesthesia when possible rather than retrobulbar or peribulbar blocks, as regional anesthesia increases the risk of extraocular muscle complications 1

Critical Caveats

• If diplopia occurs postoperatively and has not resolved or demonstrated improvement within 6 months, it is unlikely to resolve spontaneously and warrants referral to a strabismus specialist 1
• Excessive cautery, hemorrhage, and misdirected dissection are the primary modifiable risk factors, though no other specific predictive factors have been identified 1
• Even with optimal technique, the risk cannot be reduced to zero, and patients should be counseled preoperatively about this rare but serious potential complication 1, 2