Risk Assessment of Arterial Embolism from Neofilera ^® Filler in Rabbits

The incidence of vascular complications differs among dermal filler formulations. This study aimed to evaluate the embolic risk associated with Neofilera ^® , a filler composed of carboxymethyl cellulose and polylactic acid microspheres, following intra-arterial injection. The central auricular arteries of rabbits were injected with Neofilera ^® at volumes of 0.1 mL or 0.2 mL under various conditions: normal saline (control) and Neofilera ^® diluted at ratios of 1:5 (Group 1), 1:10 (Group 2), and 1:15 (Group 3). The presence of transparent emboli was assessed immediately after injection, while tissue necrosis (percentage and area) and histopathological alterations were evaluated on days 1 and 7 post-injection. Relative to controls, Neofilera ^® administered at 0.1 mL dispersed within minutes and did not induce significant tissue necrosis at either observation time point. In contrast, administration of 0.2 mL, even in diluted form, was associated with an increased incidence of vascular occlusion. Overall, these findings indicate that Neofilera ^® presents a lower embolic risk when injected at a volume of 0.1 mL, whereas higher injection volumes may substantially increase the likelihood of embolic complications.