The Linear Retrograde Infiltration (LiRi) Technique for Buttock Fat Infiltration: A Cohort Evolution

Area of Science:

• Plastic Surgery
• Aesthetic Medicine
• Regenerative Medicine

Background:

• Autologous fat grafting for buttock augmentation is popular.
• A significant risk is fat infiltration into the venous system, potentially causing fatal macroscopic fatty embolism (MAFE).

Purpose of the Study:

• To evaluate the safety and efficacy of the Linear Retrograde infiltration (LiRi) technique for autologous fat grafting in the buttocks.
• To assess the technique's outcomes over a six-month follow-up period.

Main Methods:

• The LiRi procedure was performed on 114 patients.
• Strict ultrasound guidance was employed with specific cannulas (4-5 mm basket or 4 crosshead holes).
• Cannula placement in the deep subcutaneous space, avoiding the deep gluteal fascia, was confirmed via ultrasound before retrograde fat infiltration.

Main Results:

• A low minor complication rate of 7% was observed, including fat cysts (7%), asymmetries (5%), and contour irregularities (2%).
• One case of fat necrosis occurred; no infections or fat embolisms were reported.
• No significant correlation was found between complications and patient BMI or total infiltration volume.

Conclusions:

• The LiRi technique appears safe and effective for gluteal augmentation.
• The method demonstrates consistent fat integration and minimal complications.
• Further long-term research is recommended to validate these findings.