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When to change needles during neuromodulator injections-An electron-microscopy investigation into needle tip
Lisa Akintilo1, Jeremy B Green1, Joely Kaufman1
1Skin Associates of South Florida and Skin Research Institute, Coral Gables, Florida, USA.
Background:
Neuromodulator injections are minimally invasive procedures performed across the globe. Despite their ubiquity, there is a dearth of information on whether and how needle tips used for neuromodulator procedures are deformed after repeated injections.
Objective:
We investigated the magnitude of needle tip deformation following sequential injection passes (3×, 5×, and 10×) during facial neuromodulator injections with three commonly used needle sizes (30G, 31G, and 32G).
Methods:
Neuromodulator was administered for four different aesthetic indications. Each collected needle was mounted and imaged in a Philips XL-30 Scanning electron microscope. Images were processed using ImageJ photo analysis software.
Results:
Forty-five needle tips were investigated. When comparing the facial regions of interest, a statistically significant difference in deformation percentage was found when injecting 10× (p = 0.044) with greatest damage after injecting the glabella (38.4%), followed by lateral canthus (27.9%), forehead (27.5%), and midface (23.1%). Independent of facial region targeted, the mean percentage of needle deformation at 3× was 14.8%, at 5× 19.6%, and at 10× 29.2% with p < 0.001. Smaller needle size corresponded to smaller percentage of damage.
Conclusion:
Exchanging needles after more than five injection passes will minimize needle deformation and likely increase injection precision.
