Is safety worth 5 seconds?
The popularity of procedures for introducing fillers is growing, and with it the number of complications inevitably grows (including among experienced doctors). Of course, the key to success are:
the correct technique for performing the procedure;
the choice of filler with optimal rheological properties;
knowledge of the anatomical features of the facial areas;
understanding of hazardous areas (the most dangerous areas are glabella, nose and nasolabial folds (Redaelli et al. 2017));
conducting an aspiration test before the introduction of the filler at each (!) injection.
Recently, at conferences and master classes, I increasingly hear doctors’ doubts about the need for an aspiration test in the process of introducing filler. The explanation is simple: “All cases of vascular complications that I know of occurred after receiving negative results of an aspiration test, so I don’t do it!”
And young doctors, trusting the opinion of an experienced doctor, can refuse to perform an aspiration test, which, in my opinion, will only increase the risk of vascular complications.
The classical technique of conducting an aspiration test includes several stages, at each of which you can make a mistake.
I propose to check whether we are missing any details in our work.
Insertion of a needle into tissues (knowledge of anatomy is the key to choosing the injection site – dissection courses help us!).
Fixation of a hand with a syringe relative to the face – emphasis in the face with the little finger or ring finger (I am sure that the lack of fixation and, consequently, the further movement of the needle is one of the causes of vascular complications after receiving negative results of the aspiration test).
Reverse piston movement. Let us dwell here in more detail.
This seems to be an obvious and understandable point. We all understand how to do this (even medical knowledge is not required for this, right?).
But how many seconds does this reverse piston movement take? 1 second? 2? 3? How is this interconnected with the chosen filler (its elasticity, density)? Does the length and diameter of the needle play any role?
In September 2017, the results of a study of the sensitivity of an aspiration sample before the administration of various fillers were published (Van Loghem et al. 2017). Familiar to many of you, Jani Van Lochem and two of his colleagues performed an aspiration test using 24 types of fillers and 11 different needle sizes. A needle was placed in an artificial environment with a gel (filler) located in it, simulating the intravascular introduction of the tip of the needle. Researchers recorded at which second backward movement of the piston “blood” appears at the base of the needle. Of all the studied combinations “filler + needle size”, a positive result of the aspiration test in the form of the appearance of “blood” for 1 second at the base of the needle was recorded in 33% of all combinations. Another 30% of the combinations showed a positive aspiration test from 2 to 10 seconds. The remaining 37% were false negative due to the mismatch of the needle size with the rheological characteristics of the filler.
For example, you selected Belotero Volume. Based on the results of the study, if you take 23G or 25G needles for work, you get a probable reliable result of the aspiration test at 1–5 seconds; 27G – 2-8 seconds; 28G, 30G and 33G – even after 10 seconds there will be no reliable result.
A large percentage of false negative results is primarily due to the fact that 30G and 33G needles were taken for the study of dense fillers because of the need to observe the experimental rules (in practice, we would not have thought of a dense filler injecting 30G and 33G needles through the needles).
The article with the results of the study is in the public domain. I highly recommend finding the file you use in the table with the results and comparing the time for performing the reciprocal motion of the piston, which was recorded by the authors and which you usually spend on this item.
Similar data were obtained in a recent study (January 2019), also devoted to the relationship between viscosity, filler elasticity and time of appearance of “blood” at the base of the needle (Torbeck et al. 2019).
Only after an aspiration test is it possible to introduce a filler. One of the recommendations of the authors of these studies is to avoid the introduction of large boluses (many doctors agree that microbolar technique is the safest).
Thus, an aspiration test is an important part of the filler insertion procedure. You need to carry it out at every injection!
It is important to remember that the result of an aspiration test depends on the correct selection of the diameter and length of the needle for introducing a filler with certain rheological properties.
Even if for 10,000 negative samples you get 1 positive sample, you will not introduce a filler there and save the patient and yourself from serious consequences.
Tables in the studies to help us!
The opinion of experts
“When I perform contour grafting in the middle zone on the bone and do bolus injections, I always do an aspiration test at every injection. Even if it is a theoretically anatomically safe area.