Comparison of Intra-arterial and Subcutaneous Testicular Hyaluronidase Injection Treatments and the Vascular Complications of Hyaluronic Acid Filler

BACKGROUND Hyaluronidase is a key preventative treatment against vascular complications of hyaluronic acid (HA) filler injection, but the degradation profile of HA to hyaluronidase is limited, and the comparison between intra-arterial and subcutaneous injections of hyaluronidase has not been studied. OBJECTIVE To evaluate HA degradation to hyaluronidase and compare different treatments between intra-arterial and subcutaneous testicular hyaluronidase injections. MATERIALS AND METHODS The authors observed HA degradation to hyaluronidase in vitro via microscopic examination and particle analysis. Rabbit ears were used for the in vivo study. There were 2 control groups receiving ligation or HA-induced embolism in the arteries, respectively, and 2 intervention groups receiving hyaluronidase treatments in different regions. The laser Doppler blood perfusion monitoring measurements were made at defined time points, and biopsies were taken on Day 2. RESULTS Nearly, all of the HAs degraded in vitro at the 1-hour time point. Subcutaneous hyaluronidase treatment showed better recovery of blood perfusion. Histology showed severe inflammation in the embolism group and mild inflammation in the intervention groups. CONCLUSION A complete enzymatic degradation of HA filler to hyaluronidase needs a certain time, and subcutaneous hyaluronidase treatment may be the better option.