In vitro evaluation of aspiration of hyaluronic acid filler with a new saline flashing method.

[AIMS] In vitro evaluation of aspiration of viscous hyaluronic acid (HA) fillers through dermatologic needles, with and without a new solution for safe aspiration with a saline flashing procedure. The final objective is to be able to offer an easy-to-use device for a practitioner who injects fillers under and into the skin blindly. This device aims to protect him from an immediate and reproducible intravascular venous or arterial injection whatever the type of product used and independently of its rheological properties or the diameter of the needle used.

[MATERIALS AND METHODS] We performed in vitro aspiration experiment using syringes and commonly used needle sizes (27G, 29G). We measured the time to observe a blood being aspirated through the needle with HA filler. Intervals longer than 10 seconds were considered as false results. We added a new approach of flashing a saline solution through the needle with a filler prior to aspiration. Saline solution pressurized by a syringe plunger opens a fluid path in the needle and enables the successful and efficient aspiration in 1-2 seconds through smallest needle size for 6 commercial HA fillers.

[CONCLUSION] The saline flashing of the dermatological needles with HA fillers appeared to be a feasible and efficient solution for the 100% safe aspiration safety test.

[RESULTS] Aspiration was possible only in few trials with HA fillers for the 27G and all false for 29G needle, respectively. The aspiration with the novel saline flashing procedure is successful for 100% of cases with the two commonly used HA fillers and all needle sizes. The time to aspiration is also significantly shorter with the saline flashing.