Abstract
BACKGROUND: Lip volumization using hyaluronic acid (HA) is among the most popular aesthetic procedures due to the role of the lips in modern beauty standards. This study explored the ultrasound characteristics of HA deposits following injection using either cannula or needle techniques. METHODS: A multicenter, descriptive study involving 27 patients from five aesthetic centers in Colombia, Spain, and Mexico was conducted. Ultrasound evaluations were performed pre- and post-procedure to assess anatomical changes, HA deposit morphology, and vascular mapping with Doppler. Patients were randomly assigned to either the cannula technique (11 patients, representing 41% of the cohort) or the needle technique (16 patients, representing 59% of the cohort). Satisfaction was measured using a subjective scale (1-5). RESULTS: HA doses ranged from 0.4 to 1 cc. Among the 27 patients, 25 had a single type of deposit, while two patients presented with two different types simultaneously. Ultrasound examination revealed that 81% (22 patients) of labial arteries were located in the wet submucosa, 15% (four patients) in the dry submucosa, and 4% (one patient) intramuscularly. A total of nine patients presented with lip asymmetry, and two patients had lip hypotrophy; all 11 patients achieved correction, defined as the restoration of symmetrical lip volume and contour. Patient satisfaction was universally high, with 74% (20 patients) reporting complete satisfaction. CONCLUSION: Ultrasound evaluation is an effective and safe method for assessing patients undergoing HA injections. Our observations indicate that injection techniques, whether using a needle or a cannula, influence the shape and location of HA deposits, with elongated deposits being more common with cannula use and round deposits predominantly associated with needle injections. Pre-procedure ultrasound allows for the identification of each patient's specific lip anatomy, aiding in injection planning, while post-procedure ultrasound helps verify the location of deposits and detect potential complications. These findings highlight the importance of careful technique selection and thorough anatomical assessment to optimize safety and aesthetic outcomes. Future research should focus on larger samples and long-term follow-up to validate these observations and further enhance procedural safety in aesthetic medicine.