Injections of volumizing fillers are inherently blind procedures.
Thus knowledge of anatomical structures is imperative,
in addition to the use of a proper injection technique. A
useful technique to employ to prevent vascular compromise is
aspiration of the needle after placement, to ensure the injector
is not in a vascular structure. A current limitation with the use of
calcium hydroxylapatite is the inability to fully aspirate with the
provided syringe and needle due to the increased particle size.
The particle size of calcium hyroxylapatite ranges from 25-45 microns.
Therefore, we will examine the effectiveness of aspiration
when using a different size syringe and different gauge needles.
Materials used were as follows: 27-gauge needle (Exel International
Los Angeles, CA); 28-gauge needle (Exel International
Los Angeles, CA); manufacturer-provided 1.5cc syringe (Merz
Aesthetics, Franksville, WI); 1.0cc BD syringe (Franklin Lakes,
NJ). The medium used was freshly obtained blood.
First, we utilized the manufacturer-provided syringe and
28-gauge needle with calcium hydroxylapatite that has not
been reconstituted. We attempted aspiration of the blood and
were unable to aspirate any blood product into the syringe.
We then exchanged the manufacturer-provided syringe for a
1.0cc BD syringe and utilized a 27-gauge needle. We were able
to aspirate a noticeable amount of blood both in the hub and
throughout the syringe. Next, we conducted the aspiration with
reconstituted calcium hydroxylapatite mixed with 0.3cc of 2%
lidocaine. We noticed a minimal amount of blood was aspirated
using the manufacturer-provided 1.5cc syringe and 28-gauge
needle. We then exchanged the manufacturer-provided syringe
to a 1.0cc BD syringe and 27-gauge needle with reconstituted
calcium hydroxylapatite with 0.3cc 1% lidocaine and attempted
aspiration of blood. We noted blood in the hub, as well as blood
in the syringe. The manufacturer-provided syringe and needle
was then exchanged for a 1.0cc BD syringe and a 27-gauge needle,
allowing for more effective aspiration while using calcium
hydroxylapatite. Also, reconstituting the calcium hydroxylapatite with 0.3cc of 1% lidocaine demonstrated an increased
ability to aspirate. The utility of this simple technique may reduce
the adverse events such as vascular compromise.
This simple experiment demonstrates a new method to make calcium hydroxylapatite injections safer. The particle size of calcium hydroxylapatite has limited the provider’s ability to aspirate to ensure the needle is not in a vascular structure. As vascular compromise and cutaneous necrosis is a feared complication of volumizing filler injections, we have demonstrated
a simplistic method to increase the ability to aspirate when the provider is injecting near or at a danger zone of the face.
An additional technique to complement this new method to increase the safety of calcium hydroxylapatite injection is to ensure that the provider leaves enough space in the syringe to provide an adequate vacuum effect. In order to achieve this vacuum effect, you must obtain 0.1-0.2cc of extra space in the syringe. Otherwise, the injector will have a false sense of security
that they have not infiltrated a vascular structure.
To achieve this with calcium hydroxylapatite, which comes in
manufacturer-provided 0.8cc and 1.5cc syringes, the material is
mixed with 0.3cc of 1% lidocaine. This is accomplished by attaching
the manufacturer-provided filler to one end of the Luer
Lock- to-Luer Lock connector to a 3ml BD syringe containing the
0.3cc of 1% lidocaine on the other end. The contents are then
mixed ten times and then transferred to the syringe containing
0.3cc of lidocaine. For example, utitilizing a 1.5cc of filler would
yield a total of 2.0cc of mixed filler and anesthetic. Then 1.0cc
of calcium hydroxylapatite is transferred to the original manufacturer-
provided syringe. The manufacturer-provided needle is
28- gauge size, but we recommend a 27-gauge needle size to
effectively accomplish the vacuum effect.
The most recent advance with injection techniques is the utilization
of cannulas. The use of cannulas provides an increased
level of safety during injections. However, for high volume injectors
and providers who have become experts at injecting with
needles, cannulas may not be as practical. There is a learning
curve when utilizing cannulas and this may be time consuming
to adapt into a busy practice. Thus, for the providers who are
hesitant to fully convert to using cannulas, they may consider
our new simplistic technique to increase the safety of calcium
hydroxylapatite injections near or at a danger zone of the face.
Dr. Aguilera is a trainer for Merz Aesthetics. The other authors
have not disclosed any relevant conflicts.