Creator: Dr. Liu Ta-Ju
Published: 2026-03-17
Keywords: permanent filler, liquid silicone, PAAG removal, filler migration, granuloma

Why Are Decades-Old Cosmetic Injections Causing Problems Now?

Across Taiwan, mainland China, and Southeast Asia, the 1990s through the early 2000s saw widespread use of injectable cosmetic procedures sometimes called "small needle beautification." The materials used during that era included liquid silicone, polyacrylamide hydrogel (PAAG, marketed as Amazingel or Aquamid), paraffin wax, and various other permanent or semi-permanent fillers.

These substances were injected into the face, nose, chin, forehead, and even the chest, marketed as long-lasting beauty solutions. Decades later, however, a growing number of patients are confronting serious complications: recurrent inflammation, filler migration, granuloma formation, and in severe cases, tissue necrosis.

> Key Insight: Permanent filler problems do not "fade with time" — quite the opposite. As tissues age, gravity takes effect, and the immune system fluctuates, complications from these materials tend to worsen progressively.

Common Permanent Fillers and Their Risks

Material Comparison

The Unique Problem With Liquid Silicone

Liquid silicone is never absorbed by the body and does not form stable boundaries. Its properties make it one of the most difficult fillers to manage:

• No defined margins: Silicone infiltrates tissue spaces and becomes intermingled with normal tissue

• Chronic immune stimulation: Continuously activates macrophages and foreign body giant cell responses

• Delayed granulomas: Can appear 5–30 years after injection

• Gravitational migration: Slowly tracks downward along tissue planes

The Dangers of PAAG

PAAG was widely used for breast augmentation and facial filling in mainland China before being banned due to severe complications. Its risks include:

• Bacterial colonization: The gel structure provides an ideal environment for microbial growth

• Toxic degradation: PAAG can degrade into acrylamide monomers, which are neurotoxic and potentially carcinogenic

• Diffuse infiltration: The gel can spread extensively through tissue planes

• Recurrent infection: Prone to reinfection even after antibiotic therapy

> Key Insight: The danger of PAAG lies in its degradation products — acrylamide monomer has been classified by the International Agency for Research on Cancer (IARC) as a Group 2A probable carcinogen. Long-term retention is not a safe option.

Why Traditional Wide Excision Is Not the Best Approach

The Dilemma of Open Surgery

When faced with permanent filler complications, many surgeons instinctively recommend excision. However, wide surgical excision carries significant drawbacks:

Why Doing Nothing Is Also Problematic

Some patients choose to coexist with their permanent fillers, but this carries ongoing risks:

• Continuous immune system stimulation by the foreign material

• Cumulative infection risk over time

• Ongoing filler migration

• Tissue changes that may interfere with future medical imaging

• Psychological burden of persistent concern about filler status

Ultrasound-Guided Minimally Invasive Extraction: The Precise Middle Path

Ultrasound Identification of Permanent Fillers

Different permanent fillers display distinct characteristics on ultrasound imaging:

Advantages of Minimally Invasive Extraction

Compared to traditional wide excision, ultrasound-guided minimally invasive extraction offers clear advantages:

Staged Extraction Strategy

For permanent fillers — especially widely dispersed liquid silicone — staged extraction is often the safer approach:

First Session

• Complete ultrasound assessment and mapping

• Remove filler from primary concentration areas

• Evaluate tissue response

4–8 Week Interval

• Allow tissue recovery and remodeling

• Repeat ultrasound to assess remaining deposits

Subsequent Sessions

• Target residual deposits with refined extraction

• Continue ultrasound monitoring until clinical goals are met

> Key Insight: Managing permanent fillers does not require achieving perfect removal in a single session. A staged, precise, minimally invasive approach maximizes filler removal while minimizing tissue trauma.

Site-Specific Considerations

Face (Nose, Chin, Forehead, Temples)

The face is the most common injection site for permanent fillers. Extraction requires particular attention to:

• Facial nerve anatomy: Ultrasound identifies and avoids nerve pathways

• Vascular structures: Facial artery, supraorbital artery, and other vessels must be protected

• Skin thickness: Some areas (such as the nasal dorsum) have thin skin requiring careful technique

• Cosmetic placement: Pinhole entries are placed in concealed locations

Post-Procedure Care

• Ice application for 48 hours to reduce swelling

• Avoid vigorous exercise for one week

• Attend scheduled follow-up ultrasound appointments

• Return immediately for any increasing redness, pain, or fever

When to Seek Evaluation

If any of the following apply to you, professional evaluation is recommended as soon as possible:

• You received cosmetic injections years ago with unknown materials

• The injection site shows recurrent redness, swelling, or inflammation

• You can feel hard lumps or sense that filler has shifted position

• The skin over the injection site has changed color or texture

• You are concerned about the long-term safety of permanent filler in your body

The first step is a comprehensive ultrasound evaluation to determine the filler type, distribution, and current condition.