Understanding the Interplay Between Skin, Fascia, and Muscles of the Midface in Facial Aging.

BACKGROUND: Surgical, minimally-invasive, and non-invasive aesthetic procedures try to ameliorate the signs of facial aging, but also focus on enhancing various individual features of beauty in each patient. Herein, the midface plays a central role due to its location but also its importance for the aesthetic perception and facial expression. OBJECTIVE: To date, no study has investigated the interplay between facial muscles and its connecting subdermal architecture during facial aging to provide a more comprehensive understanding of the middle face. MATERIALS AND METHODS: A total of 76 subjects, consisting of 30 males (39.5%) and 46 females (60.5%) with a mean age of 42.2 (18.7) years [range 19-80] and a mean BMI of 24.6 (3.7) kg/m2 [range 18-35], were enrolled in this investigation. Cutometry (skin aging), 3D skin displacement analyses (subdermal connective tissue aging), and sEMG (muscle aging) analyses were utilized. RESULTS: The results revealed that overall skin firmness increased, and skin elasticity decreased (p < 0.001), sEMG signal of the investigated muscles decreased (p < 0.001), whereas midfacial mobility remained unaltered (p = 0.722). CONCLUSION: The results of this study indicate that midfacial aging is a measurable effect when utilizing individual measurement modalities for assessing skin, subdermal fascia, and midfacial muscles. The function of midfacial muscles revealed a potential threshold effect, which is not reached during midfacial aging due to the unchanged soft tissue mobility at older age. However, to understand its clinical presentation all midfacial soft tissues need to be factored in and a holistic picture needs to be created. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes review articles, book reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to authors www.springer.com/00266 .

Investigating the Contraction Pattern of the Zygomaticus Major Muscle and its Clinical Relevance: A Functional MRI Study.

BACKGROUND: Our understanding of facial anatomy has significantly evolved, yet the detailed contraction patterns of facial muscles and their presentation during clinical imaging remain largely unexplored. Understanding the contraction patterns and visual presentation of these muscles, particularly the zygomaticus major could enhance pre-surgical facial assessments and the development of new treatment strategies. METHODS: A total of 34 healthy young individuals (17 female, 17 male) with a mean age of 23.6 (2.4) years [range: 20-30] were investigated regarding the length, thickness, width, and angle of the zygomaticus major muscle in five different facial expressions (i.e., repose, anger, joy, surprise, and sadness) utilizing MR imaging. RESULTS: Joyful expressions caused a reduction in muscle length to 85.6% of its original length and an increase in width (103.4%), thickness (108.4%), and facial angle (2.72°) when compared to that in repose, suggesting isotonic contraction. Conversely, expressions of anger, surprise, and sadness generally led to muscle stretching, seen through changes in length (98.9%, 104.3%, and 102.7%, respectively), width (98.8%, 96.5%, and 99.4%, respectively), and thickness (91.2%, 91.0%, and 102.7%, respectively), with variable alterations in facial angle (0.55°, 1.85°, and 1.00°, respectively) depending on the specific expression. CONCLUSION: This MRI-based study indicates that the zygomaticus major muscle experiences isotonic contraction, characterized by decreased length and increased width and thickness. The findings underline the importance of muscle thickness as a reliable parameter in assessing facial muscle function and offer valuable guidance for practitioners in accurately evaluating muscle performance during different facial expressions. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Precision in Midfacial Volumization Using Ultrasound-Assisted Cannula Injections.

BACKGROUND: Soft-tissue filler injections performed with a cannula are perceived to be less precise because of the length of the instrument and the blunt tip, which can deviate in any direction. Midfacial needle injections are favored despite the increased risk for intraarterial product placement. The objective of this study was to demonstrate that ultrasound-assisted cannula injections of the midface result in precise, safe, and effective volumization procedures. METHODS: Midfacial injections with a 22-G cannula were performed in 188 midfaces of 94 healthy volunteers [86 women; age, 53.05 (9.9) years; 23.63 (2.1) kg/m 2 ] under ultrasound-assisted guidance. Precision (ie, administration of product in the same plane as the location of the cannula tip), safety (ie, rate of adverse events), and aesthetic outcome (rated by the patient and the treating physician) were assessed. RESULTS: In 100% of cases, the product was applied into the desired deep midfacial fat compartment, and the product did not migrate into more superficial layers during the injection process or at any follow-up visit. There was a statistically significant ( P < 0.001) improvement in midfacial volume loss and the aesthetic outcome was rated as very much improved. No adverse events were reported throughout follow-up. CONCLUSIONS: Real-time imaging allows for visual feedback during cannula advancement and injection procedures in the midface and can help practitioners achieve safer aesthetic outcomes. It is hoped that practitioners decide to use a cannula more frequently for midfacial volumization, given the results presented in this article. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

How We Look At Mature Faces-An Eye-Tracking Investigation Into the Perception of Age.

BACKGROUND: It is still unclear which facial region contributes most to the perception of an aged face when evaluated by eye-tracking analyses. OBJECTIVES: The authors sought to apply eye-tracking technology to identify whether mature faces require longer fixation durations than young faces and which facial region contributes most to the perception of a mature face. METHODS: Eye-tracking analyses were conducted in 74 volunteers (37 males, 37 females; 43 ≤ 40 years, 31 > 40 years) evaluating their gaze pattern and the fixation durations for the entire face and 9 facial subregions. Frontal facial images of 16 younger (<40 years) and older (>40 years) gender-matched individuals were presented in a standardized setting. RESULTS: Independent of age or gender of the observer, a younger stimulus image was viewed shorter than an older stimulus image with 0.82 (0.63) seconds vs 1.06 (0.73) seconds with P < 0.001. There was no statistically significant difference in their duration of a stable eye fixation when observers inspected a male vs a female stimulus image [0.94 (0.70) seconds vs 0.94 (0.68) seconds; P = 0.657] independent of the observer's age or gender. The facial image that captured the most attention of the observer (rank 9) was the perioral region with 1.61 (0.73) seconds for younger observers and 1.57 (0.73) seconds for older observers. CONCLUSIONS: It was revealed that the perioral region attracts the most attention of observers and contributes most to an aged facial appearance. Practitioners should be mindful of the importance of the perioral region when designing an aesthetic treatment plan.

Quantitative Mobility Analysis of the Face and its Relevance for Surgical and Non-surgical Aesthetic Facial Procedures.

BACKGROUND: Understanding the degree of facial mobility upon postural changes is of great clinical relevance especially if facial assessment, facial measurements and/or facial markings are done in an upright position, but facial procedures are performed in a supine position. OBJECTIVE: The objective of this study is to investigate regional facial skin displacement and facial volume changes in individuals between upright and supine positions. METHODS: This multi-center study analyzed a total of 175 study participants with a mean age of 35.0 (10.2) years and a mean body mass index of 24.71 (3.5) kg/m2. 3D surface scanning technology with automated registration and alignment was utilized, and multivariate analyses were performed with adjustment for age, gender, body mass index, facial skin sagging and laxity. RESULTS: The medial face displaced less than the lateral face in both cranial (0.88 mm) and in lateral (0.76 mm) directions, and the lower face displaced more than the middle face in both cranial (1.17 mm) and lateral directions (1.37 mm). Additionally, the medial face lost, on average, 3.00cc whereas the lateral face increased by 5.86cc in volume; the middle face increased by 2.95cc, whereas the lower face decreased by 0.98cc in volume. All p < 0.001. CONCLUSION: Practitioners should be mindful that there is a statistically significant change in facial soft tissues between the upright and supine positions and that the magnitude of the change does not necessarily reflect on the aging process alone but is a multi-factorial process which should be individualized for each patient's needs. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

In Search of the Most Attractive Lip Proportions and Lip Volume: An Eye Tracking- and Survey-Based Investigation.

BACKGROUND: Despite various aesthetic trends, the ideal lip proportion and lip volume remains elusive. Thus, the aim of this study was to investigate the aesthetic perception of various lip shapes to identify the most attractive lips. METHODS: Fifty-nine White study participants with a mean age of 32.73 ± 9.4 years were asked to assess lips of various proportions and of various volumes. Gaze assessment and aesthetic rating of the same set of modified lip images were performed. RESULTS: The results revealed that the lip proportion that was rated to be most attractive was the 1:1.6 ratio (upper-to-lower lip, 4.21 of a possible 5). This lip proportion, however, was not the first one to be viewed on initial image display (1.20 sec) and had the shortest duration of a stable eye fixation within the 6-second image display interval (2.18 of 6 seconds). The lip volume that received the highest aesthetic rating was the 100 percent volume (original lip size), with 4.56 of a possible 5. This lip volume, however, had the third longest interval between initial image exposure and the first stable eye fixation (0.81 second) and had the shortest duration of stable eye fixations during the 6 seconds of image display (2.22 of 6 seconds). CONCLUSION: The results presented could be potentially reflective of the internal cognitive processes during the involuntary and voluntary assessment of lip attractiveness.

Electrophysiologic Frontalis Muscle Response Following Neuromodulator Injections.

Neuromodulator treatments limit the contractility of the frontalis muscle, resulting in reduced dynamic and static horizontal forehead line formation of the overlying skin. This interventional study investigated the electrophysiologic response (via signal-to-noise [SNR] ratio) and the overlying skin displacement of the frontalis muscle following neuromodulator injections in a total of 11 healthy neuromodulator-naïve volunteers. Relating SNR to the respective skin movement revealed that the higher the SNR, the more vertical the skin displacement is; this remained statistically relevant after gender stratification. These results are novel and will help the aesthetic community to understand neuromodulator effects on the frontalis muscle.

Reevaluation of the Layered Anatomy of the Forehead: Introducing the Subfrontalis Fascia and the Retrofrontalis Fat Compartments.

BACKGROUND: Novel imaging methods have provided new insights into the layered anatomy of the forehead. This study seeks to critically reevaluate the layered anatomy of the forehead by using ultrasound imaging and cadaveric dissection to provide an accurate anatomical description that can be used to guide safer surgical and minimally invasive frontal procedures. METHODS: This study used ultrasound imaging in a sample of 20 volunteers (12 female and eight male volunteers; aged 35.25 ± 4.2 years; body mass index, 24.28 ± 3.5 kg/m2) and cadaveric dissections of 16 body donors (12 female and four male body donors; aged 72.76 ± 9.5 years) to reevaluate the layered anatomy of the forehead. Layer-by-layer dissections and ultrasound-based measurements of the frontal structures guided conclusions. RESULTS: The following layered arrangement was identified: layer 1, skin; layer 2, superficial fatty layer; layer 3, suprafrontalis fascia; layer 4, orbicularis oculi and frontalis muscle (same plane); layer 5, a homogenous layer of fat [preseptal fat (in the upper eyelid), retro-orbicularis fat (deep to the orbicularis oculi muscle), and retro-frontalis fat (deep to the frontalis muscle); layer 6, subfrontalis fascia; layer 7, preperiosteal fat within the prefrontal space in the lower forehead and deep compartments in the upper forehead; and layer 8, periosteum. CONCLUSIONS: The results of this study add to the current understanding of the layered arrangement of the forehead. The combination of ultrasound imaging and cadaveric dissections provided evidence for a continuous fatty layer deep to the frontalis muscle.

The Difference in Facial Movement Between the Medial and the Lateral Midface: A 3-Dimensional Skin Surface Vector Analysis.

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.

The Layered Anatomy of the Nose: An Ultrasound-Based Investigation.

BACKGROUND: An increasing number of soft tissue filler procedures in the nasal region has been reported. Concomitant with demand, the number of complications has risen due to the difficulty in administering filler in a region where soft tissue layering is complex. OBJECTIVES: The authors sought to describe the layered soft tissue arrangement of the nose as it relates to the underlying arterial vasculature and to define safer zones for nasal filler enhancement. METHODS: A total of 60 (28 males and 32 females) study participants were investigated with respect to their layered anatomy in the midline of the nose utilizing ultrasound imaging. The presence and extent of the layered arrangement was examined as well as the depth of the arterial vasculature. RESULTS: In the mid-nasal dorsum, a 5-layer arrangement was observed in 100% (n = 60) of all investigated cases, whereas it was found to be absent in the nasal radix and tip. The 5-layer arrangement showed an average extent of 26.7% to 67.5% in relation to nasal length. The nasal arteries coursed superficially in 91.7% of all cases in the nasal radix, in 80% in the mid-nasal dorsum, and in 98.3% in the nasal tip. CONCLUSIONS: Soft tissue filler administration in the nose carries the highest risk for irreversible vision loss compared with any other facial region. The safety of soft tissue filler rhinoplasty procedures is enhanced by knowledge of the layered anatomy of the nose, the location and depth of the major nasal vasculature, and employment of maneuvers to decrease the risk of blindness.

Anatomy behind the Paramedian Platysmal Band: A Combined Cadaveric and Computed Tomographic Study.

BACKGROUND: The muscular hypothesis explanation of the pathophysiology behind paramedian platysmal bands does not seem to provide a sufficient explanation for the clinical presentation of these platysmal bands in aged individuals with cervical soft-tissue laxity. The purpose of this study was to investigate the fascial relationships of the anterior neck to enhance appropriate surgical treatment. METHODS: Retrospective analysis of computed tomographic scans of 50 Caucasian individuals (mean age, 55.84 ± 17.5 years) and anatomical dissections of 20 Caucasian and 10 Asian body donors (mean age, 75.88 ± 10.6 years) were conducted. Fascial adhesions were classified according to platysma fusion types, and platysma mobility was tested during dissection procedures. RESULTS: Fusion between the left and right platysma muscles occurred in 64 percent in the suprahyoid region and in 20 percent at the thyroid cartilage, and in 16 percent, the platysma attached to the mandible without fusion. In the absence of muscular fibers, a fascial adhesion zone with limited mobility was observed where the superficial cervical fascia fused with the investing layer of the deep cervical fascia. CONCLUSIONS: Muscular contraction of the platysma results in elevation of the most medial platysma muscle fibers, which are not attached in the fascial adhesion zone. The presence of a fatty layer deep to the platysma enables platysmal movement and anterior and inferior gliding of the skin and platysma when cervical soft-tissue laxity exists. Surgical treatments should include transection of the fascial adhesion; this could potentially prevent the recurrence of paramedian platysmal bands.

Treatment of Rhinophyma With Fractional CO2 Laser Resurfacing in a Woman of Color: Case Report and Review of the Literature.

Rhinophyma is a disfiguring disorder that is characterized by an erythematous, hypertrophied, and inflamed lower two-thirds of the nose. Widely accepted as the severe form of acne rosacea, rhinophyma can result in functional, aesthetic, and psychosocial concerns that require treatment in a cosmetic fashion. Rosacea should be treated in its earliest manifestations to mitigate the progression towards rhinophyma; therefore, early detection and intervention is a crucial part of treatment. Little has been written on this subject in people of color. We present the first reported case of rhinophyma in a 62-year-old Fitzpatrick V female patient who was successfully treated with one session of fractional CO2 laser resurfacing. This case highlights the successful use of the fractional CO2 laser to treat rhinophyma in darker skin types (Fitzpatrick IV–VI) and underscores the potential for future use among patients of color. J Drugs Dermatol. 2021;20(7):772-775. doi:10.36849/JDD.C702.

Understanding Facial Muscle Aging: A Surface Electromyography Study.

BACKGROUND: Facial aging is a multifactorial process that involves all tissues of the face, including skin, muscles, fat, ligaments, and bone. Whereas robust evidence is available for age-related changes of bone and facial fat, the influence of age on facial muscle activity is poorly understood. OBJECTIVES: The objective of this study was to investigate the motor unit action potential of facial muscles by utilizing surface-derived, noninvasive electromyography in young and old healthy volunteers. METHODS: The study investigated a total of 32 healthy volunteers with a mean [standard deviation] age of 42.6 [19.6] years (range, 21-82 years) and a mean BMI of 23.9 [2.7] kg/m2 (range, 18.5-29.7 kg/m2) by performing surface-derived, noninvasive facial electromyography. Nine facial muscles were investigated bilaterally, resulting in a total of 1632 measurements of the signal, baseline noise, and signal-to-noise ratio of these muscles. RESULTS: The results of the study revealed that age does not significantly influence the signal (P = 0.234), the baseline noise (P = 0.225), or the signal-to-noise ratio (P = 0.432) of younger individuals (<30 years) vs older individuals (>50 years) in a gender- and BMI-matched statistical model. Exceptions were the zygomaticus major muscle (reduced activity), procerus muscle (increased activity), and corrugator supercilii muscle (increased activity). CONCLUSIONS: The results of this facial electromyography study may help to increase the understanding of facial aging. Future studies need to reproduce the results presented herein to further increase our understanding of facial aging.

Global Recommendations on COVID-19 Vaccines and Soft Tissue Filler Reactions: A Survey-Based Investigation in Cooperation With the International Society for Dermatologic and Aesthetic Surgery (ISDS).

BACKGROUND: Recent reports have surfaced from the United States Food and Drug Administration hearings in December 2020 regarding the COVID-19 vaccines and study participants who developed facial and/or lip swelling after receiving the newly developed drug. Despite an incidence rate of 0.02% in the vaccine arm of the Moderna mRNA-1273 trial, concerns have been expressed about the association of adverse reactions following soft tissue filler injections and the COVID-19 vaccines. The International Society for Dermatologic and Aesthetic Surgery (ISDS) understands these concerns and has designed the following study. METHODS: A global survey was designed to capture the incidence of adverse events related to: (1) previous soft tissue filler injections, (2) soft tissue filler injections during positive testing for COVID-19, and (3) soft tissue filler injections during and after receiving any of the COVID-19 vaccines globally available. RESULTS: The information of 106 survey participants from 18 different countries was analyzed. 80.2% (n=85) never experienced any adverse reaction following their soft tissue filler injection whereas 15.1% (n=16) experienced swelling and 4.7% (n=5) experienced pain that lasted longer than two days. Of those who received at least one dose of the COVID-19 vaccine (n=78), 94.9% reported not to have experienced any adverse reaction related to their previous soft tissue filler injection, whereas 5.1% (n=4) reported to have perceived pain that lasted longer than two days. CONCLUSION: The data collected does not support the concern for an increased risk of developing adverse reactions following soft tissue filler injections associated with the COVID-19 vaccines compared to that risk associated with other previously described triggers or the default risk following soft tissue filler injections. J Drugs Dermatol. 20(4):374-378. doi:10.36849/JDD.2021.6041.

Quantitative Analysis of the Lifting Effect of Facial Soft-Tissue Filler Injections.

BACKGROUND: Although injectable soft-tissue fillers are frequently used for facial rejuvenation, there is a dearth of objective data evaluating the tissue-lifting effects. Current practices for efficacy evaluation include some subjectivity. This study seeks to evaluate the lifting effects of facial soft-tissue fillers in a quantifiable, objective setting. METHODS: Twenty fresh hemifaces obtained from 10 Caucasian body donors (seven women and three men) with a mean age of 83.5 ± 6.8 years and a mean body mass index of 25.3 ± 4.3 kg/m2 were injected with soft-tissue fillers following a predefined treatment algorithm. Three-dimensional surface scanning procedures were performed to assess postinjection effects. RESULTS: Injections in the medial face [i.e., forehead, medial midface, and perioral (chin and labiomandibular sulcus)] increased the local surface volume by 0.67, 0.56, and 0.87 cc and created local (but not regional) lifting effects of 1.11, 0.11, and 0.74 mm. Injections in the lateral face (temple, lateral midface, and jawline) changed the local surface volume by 0.45, 0.02, and -0.38 cc, and created local lifting effects of 0.57, 0.81, and 0.29 mm, respectively. Lateral face injections, however, created additional regional lifting effects by co-influencing neighboring lateral facial regions, which was not observed for medial face injections. CONCLUSIONS: This cadaveric study provides evidence that soft-tissue fillers, although typically classified as volumizers, can induce lifting effects of the face. Whereas temporal deep supraperiosteal injections have limited lifting effects, the combined effects of subdermal injections of the temple, lateral midface, and mandibular angle can induce lifting effects of the total lateral face. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

Performing Distance Measurements in Curved Facial Regions: A Comparison between Three-Dimensional Surface Scanning and Ultrasound Imaging.

Facial flap surgery depends strongly on thorough preoperative planning and precise surgical performance. To increase the dimensional accuracy of transferred facial flaps, the methods of ultrasound and three-dimensional (3D) surface scanning offer great possibilities. This study aimed to compare different methods of measuring distances in the facial region and where they can be used reliably. The study population consisted of 20 volunteers (10 males and 10 females) with a mean age of 26.7 ± 7.2 years and a mean body mass index of 22.6 ± 2.2 kg/m2. Adhesives with a standardized length of 20 mm were measured in various facial regions through ultrasound and 3D surface scans, and the results were compared. Regardless of the facial region, the mean length measured through ultrasound was 18.83 mm, whereas it was 19.89 mm for 3D surface scans, with both p < 0.0001. Thus, the mean difference was 1.17 mm for ultrasound measurements and 0.11 mm for 3D surface scans. Curved facial regions show a great complexity when it comes to measuring distances due to the concavity and convexity of the face. Distance measurements through 3D surface scanning showed more accurate distances than the ultrasound measurement. Especially in "complex" facial regions (e.g., glabella region and labiomental sulcus), the 3D surface scanning showed clear advantages.

Signal-To-Noise Ratio Calculations to Validate Sensor Positioning for Facial Muscle Assessment Using Noninvasive Facial Electromyography.

The evaluation of neuromodulator treatment outcomes can be performed by noninvasive surface-derived facial electromyography (fEMG) which can detect cumulative muscle fiber activity deep to the skin. The objective of the present study is to identify the most reliable facial locations where the motor unit action potentials (MUAPs) of various facial muscles can be quantified during fEMG measurements. The study population consisted of five males and seven females (31.0 [12.9] years, body mass index of 22.15 [1.6] kg/m2). Facial muscle activity was assessed in several facial regions in each patient for their respective muscle activity utilizing noninvasive surface-derived fEMG. Variables of interest were the average root mean square of three performed muscle contractions (= signal) (µV), mean root mean square between those contraction with the face in a relaxed facial expression (= baseline noise) (µV), and the signal to noise ratio (SNR). A total of 1,709 processed fEMG signals revealed one specific reliable location in each investigated region based on each muscle's anatomy, on the highest value of the SNR, on the lowest value for the baseline noise, and on the practicability to position the sensor while performing a facial expression. The results of this exploratory study may help guiding future researchers and practitioners in designing study protocols and measuring individual facial MUAP when utilizing fEMG. The locations presented herein were selected based on the measured parameters (SNR, signal, baseline noise) and on the practicability and reproducibility of sensor placement.

Differences in Temporal Volume between Males and Females and the Influence of Age and BMI: A Cross-Sectional CT-Imaging Study.

BACKGROUND: The temple has been identified as one of the most compelling facial regions in which to seek aesthetic improvement-both locally and in the entire face-when injecting soft tissue fillers. OBJECTIVE: The objective of this study is to identify influences of age, gender, and body mass index (BMI) on temporal parameters to better understand clinical observations and to identify optimal treatment strategies for treating temporal hollowing. METHODS: The sample consisted of 28 male and 30 female individuals with a median age of 53 (34) years and a median BMI of 27.00 (6.94) kg/m2. The surface area of temporal skin, the surface area of temporal bones, and the temporal soft tissue volume were measured utilizing postprocessed computed tomography (CT) images via the Hausdorff minimal distance algorithm. Differences between the investigated participants related to age, BMI, and gender were calculated. RESULTS: Median skin surface area was greater in males compared with females 5,100.5 (708) mm2 versus 4,208.5 (893) mm2 (p < 0.001) as was the median bone surface area 5,329 (690) mm2 versus 4,477 (888) mm2 (p < 0.001). Males had on average 11.04 mL greater temporal soft tissue volume compared with age and BMI-matched females with p < 0.001. Comparing the volume between premenopausal versus postmenopausal females, the median temporal soft tissue volume was 46.63 mL (11.94) versus 40.32 mL (5.69) (p = 0.014). CONCLUSION: The results of this cross-sectional CT imaging study confirmed previous clinical and anatomical observations and added numerical evidence to those observations for a better clinical integration of the data.

The Course of the Angular Artery in the Midface: Implications for Surgical and Minimally Invasive Procedures.

BACKGROUND: Previous anatomic studies have provided valuable information on the 2-dimensional course of the angular segment of the facial artery in the midface and its arterial connections. The third dimension (ie, the depth of the artery) is less well characterized. OBJECTIVES: The objective of the present study was to describe the 3-dimensional pathway of the angular segment of the facial artery and its relationship to the muscles of facial expression. METHODS: The bilateral location and the depth of the midfacial segment of the facial artery was measured utilizing multi-planar computed tomographic image analyses obtained from contrast agent-enhanced cranial computed tomographic scans of 156 Caucasians aged a of 45.19 ± 18.7 years and with a mean body mass index of 25.05 ± 4.9 kg/m2. RESULTS: At the nasal ala, the mean depth of the main arterial trunk was 13.7 ± 3.7 mm (range, 2.7-25.0 mm), whereas at the medial canthus it was 1.02 ± 0.62 mm (range, 1.0-3.0 mm). This was reflected by the arteries' relationship to the midfacial muscles: at the nasal ala superficial to levator anguli oris in 62.0% but deep to the levator labii superioris alaeque nasi in 53.6%; at the medial canthus superficial to the levator labii superioris alaeque nasi in 83.1% and superficial to the orbicularis oculi in 82.7%. CONCLUSIONS: The results presented herein confirm the high variability in the course of the angular segment of the facial artery. Various arterial pathways have been identified providing evidence that, in the midface, there is no guaranteed safe location for minimally invasive procedures.