Neurological Adverse Events Following Improper Esthetic Ultrasound Use in Facial and Neck Regenerative Medicine: Four Illustrative Cases and Safety Recommendations

Introduction: High-Intensity Focused Ultrasound (HIFU) is a widely used non-invasive esthetic treatment for facial/neck rejuvenation, inducing thermal coagulation for neocollagenesis. Despite its general safety, its non-optimal application risks neurological adverse events like tinnitus, trigeminal neuralgia, and headaches. Materials and Methods: Out of a pool of 124 patients treated with HIFU (Dual Hi; Med & Tech, Occhiobello, Italy) by experienced esthetic clinicians, four patients developed neurological or otological disturbances, which are presented as descriptive clinical case reports. These included acute tinnitus, exacerbation of pre-existing tinnitus, trigeminal neuralgia during treatment, and post-procedural headaches. To contextualize the clinical findings, relevant published literature on neurological adverse events associated with esthetic HIFU was reviewed in a non-systematic manner using major scientific databases, and used to support descriptive clinical interpretation rather than formal systematic analysis. Results: Rare transient events include acute tinnitus post-HIFU; exacerbated pre-existing tinnitus; trigeminal neuralgia during a procedure; and post-session headaches. Potential mechanisms might include thermal and mechanical nerve injury adjacent to the superficial musculoaponeurotic system (SMAS); all cases resolved successfully through tailored approaches—spontaneous resolution, corticosteroids plus hyperbaric oxygen therapy, analgesics, or ibuprofen. Conclusions: Neurological adverse effects from esthetic HIFU are uncommon/self-limiting but underscore the need for operator training, anatomical expertise, and patient history screening. Standardized protocols are essential for safety.