26/12/2025
The reason why I aspirate before administering dermal fillers right there. It is a safety measure aimed at reducing the risk of an intravascular injection (injecting the filler directly into a blood vessel).
Injecting filler into a blood vessel can lead to a serious complication called vascular occlusion, which can cause:
• Tissue necrosis (death of skin tissue) in the injected area.
• In very rare but severe cases, blindness or even stroke, particularly when injecting in high-risk areas of the face (like the nose, glabella, and forehead).
How Aspiration Works
• Placement: The needle or cannula is placed in the desired injection location.
• Pullback: The practitioner gently and slowly pulls back on the syringe plunger for several seconds (often 5 to 10 seconds). This creates negative pressure.
• Observation:
• Positive Aspirate (Blood seen): If the tip of the needle is inside a blood vessel, blood will be drawn back ("flashback") into the syringe or the needle hub. This indicates a positive aspirate, and I immediately stop change my needle and reposition before injecting.
• Negative Aspirate (No blood): If no blood appears, it is a negative aspirate, suggesting the tip is not in a vessel and it is safer to proceed with the slow injection of a small volume of filler.
Important Considerations
While aspiration is a valuable safety tool, it's not foolproof, and practitioners rely on a combination of safety techniques:
• False Negatives: The aspiration test can sometimes yield a "false negative" (no blood is seen even though the needle is in a vessel), especially with thick fillers, smaller gauge needles, or if the pull-back is not long or strong enough.
• Anatomical Knowledge: Thorough knowledge of facial anatomy, especially the location of major blood vessels, is paramount.
• Technique: Using a blunt-tipped cannula (where appropriate), injecting slowly, injecting small aliquots (small volumes), and using a retrograde (while constantly moving the needle/cannula) injection technique are all additional measures to enhance safety.
