Freehand Oblique Plane Technique for Ultrasound-guided Hyaluronidase Injections: A Modified Facial Interventional Method.

Facial ultrasound guidance has emerged as a promising technique to enhance the precision of aesthetic interventions. However, traditional in-plane and out-of-plane methods encounter challenges owing to the irregular topography of the face and confined operational space. To address these limitations, we refined the oblique plane technique by introducing 3 variations, including the long oblique plane, acute short oblique plane, and straight short oblique plane methods. The long oblique plane technique is particularly suitable for the tear trough, nasolabial fold, and medial midface, whereas the acute short oblique plane technique is more effective for the periocular and perioral areas. The straight short oblique plane method is typically used for deeper injections into the temporal and masseter muscles. A total of 115 oblique plane injections were administered to 48 female patients, with each successful injection completed within 10 seconds without significant complications. This modified approach facilitated needle visualization and tracking, shortened the learning curve for practitioners, and enhanced operational flexibility. Meanwhile, the techniques described earlier are effective for hyaluronidase, filler, or fat injection procedures.