These days there is much media attention to the use of blunt-tipped cannulas. They are touted to reduce the number of sticks, to be less uncomfortable and to minimize bruising when injecting volumizing agents, like Perlane and Radiesse.
I began using cannulas for volumizers a couple of years back, in my office abroad, since they were available there, as with so many other agents, long before receiving approval from the FDA.
Unfortunately, it wasn't long before I discovered that patients could in fact experience bruising, particularly at the entry puncture site where a needle of a diameter slightly larger than the cannula itself must be used to create an opening through which the cannula can be inserted.
Since the cannula must be inserted from a site far distant from the treatment site, some patients complained of an uncomfortable feeling as the cannula "slithered" and made a cruncy sound under their skin. I also found that treating something from afar gave me somewhat less precision in material placement. They are also not recommended for superficial treatment of finer wrinkles.
Today, both in my foreign and Upper East Side New York City offices, I have gone back to using needles, however, with a different technique known as the "Tower Technique." At each location I instill the material in an amount that places the most material at the base and a tapering amount closer to the surface--creating a shape that looks much like a cone under the skin. Each "tower" acts as a support buttress to the skin and only a few cones are required to give the needed support--reducing the number of sticks needed.
In addition, with this technique I can precisely place my material exactly where I need to in order to elevate depressions or to contour the skin. To minimize bruising I include a little epinephrine in every syringe to constrict blood vessels and I inject very slowly using a "push forward" technique in which I entered the skin and the inject the material forward of the needle so that the material itself, rather than the needle, dissects its way to the appropriate location. Each syringe also contains lidocaine to reduce discomfort. In this manner, I can achieve overall precise placement and little bruising or discomfort.