Frank, Konstantin

Abstract Background Injectable soft tissue fillers are used on a global scale for a variety of aesthetic indications. Despite their widespread use, there is a dearth of information regarding needle deformation following injection procedures. Repeated injections with the same needle could lead to progressive needle tip deformation, potentially resulting in decreased precision and increased patient discomfort. Objectives The objective of this study was to quantify the magnitude of needle tip deformation utilizing scanning electron microscopy (SEM) image analysis. Methods An observational study was performed evaluating 4 differently sized needles following soft tissue filler injections for 5 different aesthetic indications (zygomatic arch, infraorbital, midcheek, nasolabial sulcus, and perioral) in patients aged 36 to 64 years. Following treatment, each needle was visualized and imaged through SEM, and the percentage of deformation in relation to the total amount of needle tip surface was calculated. Results The factor most influencing needle tip damage was revealed to be the number of injection passes, ie, dermal transitions. Per injection procedure, an increase in needle tip damage of 4.7% occurred. Touching the bone deformed the needle tip by 9.6% and an increase in needle size resulted in 0.13% more damage. Conclusions To the authors’ knowledge, this is the first SEM investigation to provide objective evidence for the deformation of needle tips after repeated facial soft tissue filler injections. These data may help improve patient safety and comfort during these minimally invasive procedures. Level of Evidence: 3

Abstract Background Our understanding of the functional anatomy of the face is constantly improving. To date, it is unclear whether the anatomic location of the line of ligaments has any functional importance during normal facial movements such as smiling. Objectives The authors sought to identify differences in facial movements between the medial and lateral midface by means of skin vector displacement analyses derived from 3-dimensional (3D) imaging and to further ascertain whether the line of ligaments has both a structural and functional significance in these movements. Methods The study sample consisted of 21 healthy volunteers (9 females and 12 males) of Caucasian ethnic background with a mean age of 30.6 (8.3) years and mean BMI of 22.57 (2.5) kg/m2. 3D images of the volunteers’ faces in repose and during smiling (Duchenne type) were taken. 3D imaging-based skin vector displacement analyses were conducted. Results The mean horizontal skin displacement was 0.08 (2.0) mm in the medial midface (lateral movement) and was −0.08 (1.96) mm in the lateral midface (medial movement) (P = 0.711). The mean vertical skin displacement (cranial movement of skin toward the forehead/temple) was 6.68 (2.4) mm in the medial midface, whereas it was 5.20 (2.07) mm in the lateral midface (P = 0.003). Conclusions The results of this study provide objective evidence for an antagonistic skin movement between the medial and lateral midface. The functional boundary identified by 3D imaging corresponds to the anatomic location of the line of ligaments. Level of Evidence: 4

Abstract Background Since the emergence of the COVID-19 pandemic facecovers have become a common sight. The effect of facecovers on the gaze when looking at faces has not yet been assessed. Objectives The aim of the present study was to investigate any potential differences in eye movement pattern in observers exposed to images showing a face without and with a facecover to identify if there is truly a change of gaze when identifying (masked) facial features. Methods The eye movement of 64 study participants (28 males and 36 females) with a mean [standard deviation] age of 31.84 [9.0] years was analyzed in this cross-sectional observational study. Eye movement analysis was conducted based on positional changes of eye features within an x- and y-coordinate system while two images (face without/with facecover) were displayed for 8 seconds. Results The results of this study revealed that the sequence of focusing on facial regions was not altered when wearing a facecover and followed the sequence: perioral, nose, periorbital. Wearing a facecover significantly increased the time spent focusing on the periorbital region and also increased the number of repeated eye fixations during the 8-second visual stimulus presentation. No statistically significant differences were observed between male and female participants in their eye movement pattern across all investigated variables (P > 0.433). Conclusions The altered eye movement pattern caused by wearing facecoverings that this study has revealed suggests that, during the COVID-19 pandemic, aesthetic practitioners might consider developing marketing and treatment strategies that principally target the periorbital area.

Abstract Background Injecting soft tissue fillers into the deep plane of the forehead carries the risk of injection-related visual compromise due to the specific course of the arterial vasculature. Objectives The aim of this study was to investigate the 2- and 3-dimensional location of the change of plane of the deep branch of the supratrochlear and supraorbital artery, respectively. Methods A total of 50 patients (11 males and 39 females; mean age, 49.76 [13.8] years, mean body mass index, 22.53 [2.6] kg/m2) were investigated with ultrasound imaging. The total thickness and the distance of the arteries from the skin and bone surface were measured with an 18-MHz broadband compact linear array transducer. Results The deep branch of the supraorbital artery changed plane from deep to superficial to the frontalis muscle at a mean distance of 13 mm (range, 7.0-19.0 mm) in males and at 14 mm (range, 4.0-24.0 mm) in females and for the deep branch of the supratrochlear artery at a mean distance of 14 mm in males and females (range, 10.0-19.0 in males, 4.0-27.0 in females) when measured from the superior orbital rim. Conclusions Based on the ultrasound findings in this study, it seems that the supraperiosteal plane of the upper and lower forehead could be targeted during soft tissue filler injections because the deep branches of both the supraorbital and supratrochlear arteries do not travel within this plane. The superficial plane of the lower forehead, however, should be avoided due to the unpredictability and inconsistent presence of the central and paracentral arteries. Level of Evidence: 4

Abstract Background The most severe complications following soft tissue filler injections result from the intraarterial administration of the filler product. Although hyaluronic acid–based filler can be trans-arterially dissolved with hyaluronidase, no information is available on calcium hydroxylapatite (CaHA)-based fillers. Objective The authors sought to test whether CaHA-based fillers can be trans-arterially dissolved by sodium thiosulfate (STS) when evaluated in cadaveric and in vitro models. Methods Human cadaveric facial arterial segments were each filled with 0.2 cc of commercially available CaHA product and submerged for 24 hours in 4 different STS-containing solutions: 10 cc STS (300 mg/cc) (pure, 1:1 dilution, 1:2 dilution), 0.9% saline and 10 cc STS (300 mg/cc), and 300 IU (bovine) hyaluronidase in a 1:1 ratio. Results Intraarterial CaHA was detected in human facial artery segments after 24 hours independent of the STS concentration employed. Submerging the arterial segments in STS (300 mg/cc) and 300 IU (bovine) hyaluronidase (1:1 ratio) also did not dissolve the intraarterial CaHA product. Gray scale analyses did show, however, that increasing concentrations of STS resulted in increased disintegration of CaHA in an in vitro experimental setting. Conclusions The results of this study indicate that STS is limited in its potential to dissolve intraarterial CaHA of cadaveric human facial arteries, despite the fact that it appears effective when in direct contact with the CaHA. Adverse events caused by intraarterial administration of CaHA-based fillers still lack a suitable antidote.