There is an ongoing debate among injectors as to what method of injecting fillers is more accurate. The needle pundits state that the needle can inject in any tissue, at any depths. While this is true, is the filler actually placed where they think it is? Cannulas aficionados argument is that cannulas will stay in the plane which they are placed, and are therefore more accurate.
In a paper titled “Precision in Dermal Filling: A Comparison Between Needle and Cannula when Using Soft Tissue Fillers.” by Pavicic, Frank, Cotofan, et all, the debate was studied. There were 10 cadavers studied for supraperiosteal injections. The filler injected was radiopaque. Needles were placed in position using a perpendicular transcutaneous approach. The cannulas were placed in a similar position in the supraperiosteal plane. Using fluoroscopy, the injected material was analyzed in the horizontal and vertical planes.
The results show that in over 60% of the needle injections, the material changed planes (became more superficial) and this was not found in the cannulas group.
The conclusion was that cannula filler placement is more precise because the filler remains in the plane of the intended implantation much more so than needle placement.