Perceived User Experience, Comfort, and Ergonomics of an Add-on Backstop for Hyaluronic Acid Filler Injections: A...

Hyaluronic acid (HA) fillers are widely used in cosmetic dermatology. These products exhibit viscoelastic properties and often high viscosity, which may require substantial injection forces during injection. In clinical practice, repeated injections and sustained manual force may increase operator effort and contribute to hand fatigue. Device ergonomics may therefore influence perceived comfort and control during HA filler administration.

To assess the perceived aspiration and injection experience, comfort, satisfaction, and perceived ergonomics of an investigational add-on device consisting of a redesigned backstop and reinforced plunger rod for use with prefilled hyaluronic acid syringes during simulated aesthetic injection tasks.

In a late formative Human Factors study, 30 aesthetic healthcare professionals in China and Korea performed simulated HA injections using the investigational add-on device with both needle and cannula on facial training models. The primary evaluation focused on perceived user experience with the investigational add-on under simulated-use conditions. A separate exploratory contextual comparison was then conducted using the investigational add-on configuration and a standard backstop/plunger-rod configuration with needle only. The exploratory contextual comparison was open because the configurations were visually and physically distinguishable; the order of configurations was randomized. Outcomes included task observation, first impression, injection and aspiration experience assessed using visual analogue scales, comfort and perceived ergonomics assessed using user-reported Likert scales, overall satisfaction, and qualitative feedback. Data were analyzed descriptively.

Participants had a mean of 8.6 years of aesthetic practice. During simulated injections with the investigational add-on device, mean injection experience scores ranged from 8.6 to 8.9/10, and comfort scores from 5.3 to 5.4/6 for needle and cannula use. Ergonomics was rated positively by most participants, with a mean score of 5.5/6. Qualitative feedback frequently mentioned improved grip stability and reduced perceived needle-tip movement during aspiration in the simulated-use setting.

In this simulated-use late formative study, experienced aesthetic healthcare professionals reported high perceived user experience, comfort, and perceived ergonomics with the investigational add-on device. These findings should be interpreted as immediate subjective user feedback and require confirmation in studies using objective biomechanical measures and clinical-use conditions.