PEER-REVIEW | INJECTABLES | extrusion port should be as near as possible to the tip


to more precisely place the cosmetic filler product exactly where intended. For example, if you wish to inject the most lateral corner of the lip, you don’t want the filler to be extruded so medial that you have to attempt to massage it into the intended corner.


Selection of fillers It seems that a new cosmetic injectable filler always seems to be arriving that is purportedly longer–lasting and smoother. Microcannulas may be used with nearly every type of cosmetic filler, but the nature of the filler will direct the size of the microcannula. Typically, the author matches the size of the microcannula to the gauge of the recommended needle. If difficult to extrude, the author simply selects a larger gauge microcannula. If there is too much entry trauma, bruising, or pain, a smaller gauge microcannula and corresponding pilot needle is selected but extra care must be taken not to inject too forcefully or too quickly to overstress the hub’s original design parameters. Another consideration is for those who dilute their cosmetic filler in different manners so that the viscosity of the filler is changed. For example, the author typically dilutes Juvederm Ultra with 1.0 cc of 2% lidocaine when injecting the temporal areas to minimise apparent ‘lumpiness’ in this thin-skinned area. The author’s cosmetic filler of choice is usually a hyaluronic acid16


, such as


Juvederm or Restylane, because any imperfection can easily be remedied with the enzyme hyaluronidase17


. The


Figure 3 Comparison of side port locations among different cannulae.


properties for desired applications, such as Radiesse


for the dorsum of hands. He minimises use of fillers that cannot be modified without the need for surgical excision and the resulting risk of scar formation.


Microcannula basics Traction Inadequate traction is where most beginner microcannula users often fail. They fail to retract the skin adequately to insert the pilot needle and the blunt tip repeatedly snags on loose skin at attempted entry, causing more pain than if a needle were used. The author uses a technique to create enough skin tension to promote optimal resistance for entry in the direction of the insertion. The injector would typically


The author’s cosmetic


author also wants a cosmetic injectable filler that can dissolve almost instantly if there is an accidental cannulation of a blood vessel. Nevertheless, the author recommends physicians try all the comparable products on the market before arriving upon your individual selection. The author does use other fillers if they possess special


filler of choice is usually a hyaluronic acid, such as Juvederm or Restylane, because any imperfection can easily be remedied with the enzyme hyaluronidase.


place traction in the direction opposite to the injecting direction of the microcannula, with the exception of the lips, where the lip are often pulled into the direction in which the injector wishes the microcannula to travel.


Figure 4 The long micro-cannula double cross-hatched technique (Lee XX)


Depth Originally, injectors were trained to inject into the mid-to- deep dermis for cosmetic filler placement. With microcannula, however, the placement depends upon the cosmetic filler chosen and ranges from the dermal- subcutaneous (dermal-SQ) junction for most hyaluronic acid fillers to supra-periosteal for Juvederm Voluma. A significant change in the duration of action of any given filler by placement in the dermal-SQ junction instead of the dermis itself has yet to be witnessed and the author is unaware of any current research to this effect. Depth adjustment must also be made automatically to be deep enough to hide the appearance of lumpiness and to adjust for the thinness of the skin with ageing. The author observes that the deeper the filler placement — the more you need — and that less product is required with more superficial placement to correct wrinkles.


90°


The entire nasolabial fold can be encompassed with only two pilot holes using the LeeXX technique


28 ❚ January/February 2015 | prime-journal.com


Long microcannula double cross- hatched fan (LeeXX) technique Many years ago, the author observed that the short ½” needles included with Juvederm syringes required three traumatic needle insertions to encompass the length of the typical nasolabial fold. He went on to achieve the same results by replacing the ½” needle with the longer 1½” needle — with only one painful injection instead of three. Then, when the microcannula obtained FDA approval and became available in the USA, the author replaced the 1½” needle with the 1½” microcannula. Seeking the best way to use the microcannula, and the least amount of needle trauma for the smoothest and most natural appearing results, the author applied the


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