MIAMI BEACH – As more U.S. dermatologists are using cannulas to deliver soft tissue fillers for rejuvenation, tips to refine the technique and optimize patient outcomes are emerging.
Cannula use "seems to be gaining a lot of momentum in this country, and some of that really stems from the European experience," Dr. Joel L. Cohen said in an interview.
The size of the cannula, as well as the gauge of the needle that creates the entry point, can determine outcomes in different anatomic areas, Dr. Cohen said at the South Beach Symposium. "Cannulas have very specific roles in very specific areas. Personally, I have found them useful in the cheek, the infraorbital area, in the décolleté, and the dorsal hands."
He also shared a practical tip that eases cannula insertion. To deliver filler product using a 27 G cannula, for example, Dr. Cohen first nicks the skin with a slightly larger 25 G needle where he wants his entry point. Then, he pinches and holds the skin around the needle while his assistant removes it. That way, he knows the precise point to insert the cannula "rather than [later] fumbling around in a little bit of bleeding to find it. It’s really a helpful trick we’ve incorporated into our office."
A 25 G cannula can also be used to deliver fillers to the décolleté or dorsal side of the hands, said Dr. Cohen, who is in private practice in Englewood, Colo. In contrast, a smaller 30 G cannula may be more appropriate for rejuvenation of the infraorbital area, he said. "Using a 30 G cannula below the eyes, I feel that I am seeing less bruising and less swelling in this area, but at the same time, I am able to precisely deliver the filler product deep into the muscle along the periosteum."
An ability to fan product out in multiple directions from one entry point is an advantage of the cannula. "It’s a useful technique, and cannulas have helped me get better results with less bruising in my practice," Dr. Cohen said. The lower bruising potential seems to come from the cannula’s blunt tip, which can tuck under, above, or around a blood vessel. In contrast, a sharp needle is more likely to puncture the same vessel and cause postprocedure bruising, he said. And, fanning a needle around under the skin can increase the risk of bruising even further (Derm. Surg. 2008;34:S105-9).
"Some physicians, including me, actually have found patients experience less pain" with a cannula than with a needle, he added.
Although dermatologic use of cannulas has grown over the past year, "I don’t think it’s going to completely take over. You definitely still need needles for many different areas. I continue top use needles in the nasolabial folds [and] the oral commissure. For fine lines and wrinkles and more shallow rhytids, you definitely still need needles," he said
More information on cannulas can be found in an article published by Dr. Cohen and his colleague Dr. Joshua A. Zeichner (J. Drugs. Dermatol. 2012;11:70-2).
Dr. Cohen reported that he had no relevant disclosures.