Comparison of histopathological findings and flap survival following 4 different dermal filler material induced vascular occlusion.

Aim: This experimental study was designed to comparatively evaluate the damage, histopathological findings and flap necrosis rates due to vascular occlusion caused by intraarterial injection of dermal fillers calcium hydroxylapatite, polycaprolactone, agarose gel, hyaluronic acid and serum physiologique. Material and Methods: Study was conducted using 120 rats, 100 of 120 rats were divided into 5 groups, 0.02 ml of 4 different dermal fillers and serum physiologique were injected into the both side inferior epigastric arteries, 40 arteries were used in each group. For each group, samples taken from 8 vessels for histopathological examination at 0 hour, 1 hour, at 3 hours, at 24 hours, and at 1 week. Degeneration-necrosis, inflammation, fibroblast and collagen densities in the intima and media layers of the vessels, the presence of thrombus in the vessels, the presence of edema, PMNL, lymphocyte, mast cell, macrophage and eosinophil percentages and the presence of calcification were evaluated. The remaining 20 rats, 40 flaps created in both sides nourished by the inferior epigastric arteries were also divided into 5 different injection groups to create artery occlusion and used for the evaluation of flap necrosis rates 1 week after injection . Results: There was a statistically significant difference in percentage of flap necrosis value between the groups. Post-HOC showed that the difference was due to the HA group which has higher necrosis percentage. It was observed that thrombus filling the whole lumen was higher in the HA group compared to the other groups at all hours and in the first week. When intima and media degenerations, were examined there was a statistically significant difference at all times and in all groups and significant difference at certain times when examine distribution of PMNL, lymphocyte, mast, and macrophage. When eosinophil measurement, inflammation, fibroblast densities and collagen densities, edema and calcification findings were evaluated, no significant difference was found between the groups Conclusion: It was concluded that besides statistically significant histopathological differences between each fillers within the artery, in particular, the hyaluronic acid group caused thrombus, which completely occluded the lumen, significantly more than the other groups, and accordingly, the flap necrosis rate was significantly higher than the non-HA filler groups. This result highlighted the importance of antithrombotic and thrombolytic therapy especially in hyaluronic acid fillers.