The Brazilian Butt Lift (BBL) is a body contouring procedure that enhances the size and shape of the buttocks using a patient’s own body fat. This technique, known as autologous fat grafting, involves removing fat from one area and strategically injecting it into the gluteal region. The amount of fat required is specific to the individual, depending on their existing body structure and desired aesthetic outcome. Determining the necessary volume involves assessing available fat stores and factoring in fat cell survival.
Assessing Donor Site Suitability
The procedure’s success begins with the availability of harvestable fat. Fat is typically removed using liposuction from areas like the abdomen, flanks, lower back, or thighs. The patient must have adequate subcutaneous fat reserves to allow for a successful harvest and contouring of the donor area.
A patient’s Body Mass Index (BMI) is a primary consideration; those falling in the range of 23 to 28 generally possess sufficient fat for a significant enhancement. If a patient is very lean, they may still qualify for a “skinny BBL.” However, the surgeon might need to harvest fat from multiple, smaller sites to collect the necessary volume. Patients with a low BMI may be advised to safely gain a small amount of weight prior to the procedure to ensure an adequate supply of donor fat.
The total volume of material harvested, called the lipoaspirate, is not the final usable volume for transfer. This initial volume contains a mixture of viable fat cells, oil, blood, and the tumescent fluid injected during liposuction. The fat must be purified, often through centrifugation, to separate the healthy fat cells from the non-viable components. Only the purified, concentrated fat is suitable for injection, meaning the final usable volume is often only 40% to 50% of the total lipoaspirate collected.
Calculating the Volume Needed for Results
The required volume for a BBL is tailored to the patient’s anatomy, existing hip-to-waist ratio, and aesthetic goals. A surgeon determines the final volume based on whether the patient desires subtle contouring or a more dramatic increase in projection and size. For a subtle enhancement, the injected volume might be around 300 to 500 cubic centimeters (cc) per side. A more significant augmentation can require 800 cc to 1,000 cc or more per side.
The maximum amount of fat that can be safely injected is limited by the capacity and elasticity of the patient’s gluteal tissue. Injecting too much fat can compromise the blood supply to the fat grafts and increase the risk of complications like fat necrosis or oil cysts. The surgeon continues the injection process only until the tissue feels adequately full and firm, avoiding excessive pressure.
The surgeon must also factor in the expected rate of fat graft retention when planning the procedure. Because a portion of the injected fat will not survive, the initial volume transferred is intentionally an overcorrection. This calculation ensures that the final, settled volume after the initial loss aligns with the patient’s desired outcome. The goal is to achieve a balanced and proportionate silhouette that complements the newly contoured donor areas.
The Reality of Fat Graft Retention
Not every transferred fat cell will survive in its new location. The typical fat graft retention rate, or the percentage of injected fat that remains long-term, is often cited to be between 50% and 80%. This natural attrition occurs because the transferred fat cells must establish a new blood supply in the recipient area. The initial volume loss usually occurs within the first few months following the procedure.
The surgeon’s technique significantly influences the survival of the transferred cells. Using a gentle, low-pressure method during the initial liposuction helps maintain the viability of the harvested fat cells. The fat is then injected using a micro-droplet technique, placing small amounts of fat into multiple layers of the subcutaneous tissue. This strategic placement maximizes the surface area contact between the fat grafts and the surrounding tissue, increasing the chance of establishing a blood supply.
Post-operative care is a major factor in maximizing retention. Patients must strictly avoid applying direct pressure to the buttock area for several weeks, as this can crush the delicate fat cells and impair blood flow. Maintaining a stable weight and following a healthy diet supports the integration of the surviving fat grafts. Significant weight fluctuations after recovery can affect the long-term size and shape of the augmentation.