An Islanded Rabbit Auricular Skin Flap Model of Hyaluronic Acid Injection-Induced Embolism

Hyaluronic acid (HA) injection-induced embolism is a rare but severe complication. This article is aimed to introduce an islanded rabbit auricular skin flap model of HA injection-induced embolism and to study its pathophysiological progress. An islanded skin flap was elevated based on the proximal central auricular artery/vein. Eighteen rabbits were randomized into three groups. Ten, twenty, and forty microliters of HA were injected into the central auricular artery in each group, respectively. Flap fluorescence angiography was performed. One-way ANOVA was used to compare fluorescence area at different time points and between dose groups. Two rabbits in each group were randomly chosen for histology examination. In addition to regular HE staining, Alcian Blue staining was performed to better show the existence of HA in the vessel lumen. The mean calculated fluorescence area was 64.41 % on POD 1, 79.77 % on POD 3, 88.20 % on POD 5, and 92.03 % on POD 7 in 10 mu l group; 60.51 % on POD 1, 58.84 % on POD 3, 71.20 % on POD 5, and 76.54 % on POD 7 in 20 mu l group; 21.60 % on POD 1, 3.08 % on POD 3, 2.91 % on POD 5, and 7.52 % on POD 7 in 40 mu l group. In all three groups, infiltration of eosinophilic granulocytes was observed in the muscular layer of both artery and vein. Our study successfully created a rabbit auricular skin necrosis model of HA embolism, which provided a valuable animal model for further investigation of the pathophysiological progress and the efficacy of potential treatments. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.