Article

Lipoinjection

Lipoinjection is a technique in which autologous fat is harvested from one part of the body and injected into another, commonly used in gluteoplasty (Brazilian Butt Lift) to augment the buttocks. The process involves gentle liposuction, fat processing, and reinjection through small cannulas. Advantages include use of the patient's own tissue and minimal scarring. Risks include fat resorption, asymmetry, and fat embolism. See also brazilian_butt_lift, gluteoplasty, fat_embolism.

Harvesting Process

The gentle liposuction technique for harvesting fat involves several specific steps:

  1. Anesthesia: Tumescent anesthesia is often used, involving the injection of a dilute lidocaine solution mixed with epinephrine into the fatty tissue to provide local anesthesia and reduce bleeding.
  2. Incisions: Typically very small incisions (less than 3 mm) are made in隐蔽 areas like the abdomen or flanks, through which the cannula is inserted.
  3. Cannula Technique: Using a gentle technique with specialized "micro-cannulas" (often with multiple side holes), surgeons carefully aspirate fat cells while minimizing trauma to surrounding tissues and blood vessels.
  4. Fat Processing: The harvested fat undergoes processing. This usually involves:
    • Centrifugation: Separating the tissue using a centrifuge device into distinct layers based on density, allowing collection of the purest stem cell fraction for reinjection.
    • Enzymatic Digestion (optional): Using enzymatic solutions (like Zyderm or Zyplast developed by Mentor) in conjunction with liposuction to break down connective tissue more effectively before aspiration, potentially improving yield and viability. This method is often used for autologous fat grafts using the SMAS technique.

Comparison of Fat Processing Methods

Different methods exist for processing harvested fat prior to reinjection:

  • Centrifugation: Involves spinning a mixture of aspirated tissue in a centrifuge, separating it into strata (cream on top containing mature adipocytes and stem cells; middle layer with stromal vascular fraction [SVF] - crucial for survival); the cream is collected. This method relies on density separation.
  • Enzymatic Digestion: Enzymes are added during liposuction or post-aspiration to digest septin filaments, releasing viable adipocytes (fat cells) and regenerating SVF more effectively than mechanical disruption alone.

Effectiveness/Outcomes Comparison

Centrifugation is widely adopted for its ability to separate the purest fraction of autologous fat grafts containing a high concentration of mature adipocytes and stem cells. Enzymatic digestion can improve the recovery rate, particularly in cases with limited donor tissue or denser areas like upper abdomen/thighs. The choice often depends on the desired outcome (e.g., volume vs. quality/survival) and is sometimes combined for optimal results.

Fat Resorption Comparison

Studies comparing fat resorption rates between autologous fat grafting (which lipoinjection describes as a core component) and other techniques like implants are ongoing. Generally, significant differences in overall complication profiles exist:

  • Autologous Fat Grafts: While they do undergo resorption over time (typically 30-50% loss within the first year), this process is often less severe than necrosis potentially seen with larger implant volumes or different types of implants. Furthermore, fat grafting integrates vascular supply, allowing some cells to survive permanently.
  • Implants: Silicone or polypropylene mesh implants can face issues like capsular contracture and infection which are distinct from resorption but contribute to long-term complications.

However, specific quantitative comparisons highlighting differences in fat resorption rates alone versus implants often require detailed review of the study methodology. Standard texts on aesthetic surgery discuss both as having unique failure profiles (TODO: add citation).

Asymmetry Rates

Typical reported rates for minor asymmetry following fat-based augmentation range from 5-10% based on patient self-assessment or clinical evaluation, though significant correction may be required by a higher percentage (TODO: refer to specific studies comparing self-reported vs clinician-diagnosed asymmetry). Surgeons address this issue through:

  • Strategic Fat Placement: Placing fat in precise amounts and locations.
  • Post-Operative Massage: Applying manual lymphatic drainage or massage techniques, often starting immediately post-procedure (e.g., first week) and continuing for months afterward, helps distribute the grafts evenly and break down fibrous septae that can lead to lumpy appearance.

Fat Embolism - Risk Manifestation

Fat embolism syndrome (FES) manifests clinically with symptoms appearing within 24-72 hours post-procedure. These include:

  • Respiratory distress: Shortness of breath, hypoxia, nonproductive cough.
  • Neurological changes: Confusion, restlessness, headache, altered consciousness.
  • Ecchymosis (bruising): Petechiae or ecchymoses on the conjunctiva, neck, axillae, chest wall, and extremities. Severe cases can lead to pulmonary edema, renal failure, coma, or shock.

Prevention Protocols

Recommended protocols focus primarily on:

  • Avoiding High Pressure: Minimizing high pressure during fat injection is crucial (TODO: add reference). Injecting under moderate-to-low pressure increases the risk of FES significantly.
  • Using Large Caliber Cannulas at Low Depth: Some techniques suggest using cannulas with diameters greater than 3 mm and injecting below the deep venous system level in specific donor areas might reduce embolization risk, though this is debated. The most consistent advice remains minimizing high pressure during injection.

Comparison of Scarring

Lipoinjection typically results in minimal scarring due to its use of small cannulas for both harvesting and reinjection.

  • Minimal Scarring - Lipoinjection: Incisions are usually very small (< 3 mm), leading to minor, often barely visible marks once healed. The procedure involves less tissue trauma compared to major flap surgeries.

Other surgical methods with more significant scarring include:

  • Autologous Fat Transfer Using SMAS: This is a specific type of breast or buttock augmentation where the patient's own tissue (skin) is repositioned and sutured, often leaving more noticeable scars.
  • Fat Grafting using other techniques might involve larger cannulas or multiple injection sites: While generally less invasive than SMAS, they can still result in bruising and minor scarring.

In summary, the inherent use of autologous tissue minimizes rejection compared to implants. The technique allows for volume addition while utilizing existing body fat reserves (TODO: add citation).