After a Brazilian butt lift, a portion of the transferred fat cells must establish a new blood supply in their recipient site. When fat cells fail to do this, due to insufficient blood flow, infection, or trauma, they die. This process is called fat necrosis. While a small degree of fat cell death is normal and expected (accounting for the typical 20–40% reabsorption), more significant fat necrosis can cause palpable lumps, contour irregularities, or in some cases, infection.
What Causes Fat Necrosis After BBL?
Several factors can increase the risk of fat necrosis following fat transfer:
- Direct pressure on the buttocks: Sitting on the transferred fat before it has vascularized compresses and damages fat cells
- Smoking: Nicotine restricts blood vessels, reducing oxygen delivery to transferred fat
- Large volumes of fat in a single area: Overfilling a pocket reduces the surface-area-to-volume ratio needed for vascularization
- Injection into deep muscle: A technique now discouraged as it increases fat embolism and necrosis risk
- Poor fat quality or processing: Fat that is not properly harvested and processed has lower survival rates
- Infection at the graft site: Infection destroys tissue including transferred fat cells
Signs and Symptoms of Fat Necrosis
Fat necrosis most commonly presents as firm lumps or nodules under the skin in the gluteal area. Symptoms may include:
- Hard, palpable lumps beneath the skin that feel distinct from surrounding tissue
- Skin dimpling or contour irregularities over affected areas
- Tenderness or warmth over a specific spot (may indicate secondary inflammation or infection)
- In severe cases, skin discoloration or breakdown over the necrotic area
Treatment Options
Treatment depends on the size and severity of the necrosis:
- Small, asymptomatic nodules: Often monitored over time, many calcify and remain stable without requiring treatment
- Larger or symptomatic areas: May require aspiration (needle drainage) if liquefied, or surgical excision if the necrosis has formed a firm, calcified mass
- Infection: Requires antibiotics and potentially surgical debridement
- Contour irregularities: Can sometimes be corrected with additional fat grafting or revision liposuction after complete healing
The best prevention for fat necrosis is strict adherence to your surgeon's post-operative instructions, most importantly, avoiding direct pressure on the buttocks for the full 6–8 weeks following your BBL.