Can smiling influence the blood flow in the facial vein?—An experimental study

Soft electrodes for simultaneous bio-potential and bio-impedance study of the face

The human body's vascular system is a finely regulated network: blood vessels can change in shape (i.e. constrict, or dilate), their elastic response may shift and they may undergo temporary and partial blockages due to pressure applied by skeletal muscles in their immediate vicinity. Simultaneous measurement of muscle activation and the corresponding changes in vessel diameter, in particular at anatomical regions such as the face, is challenging, and how muscle activation constricts blood vessels has been experimentally largely overlooked. Here we report on a new electronic skin technology for facial investigations to address this challenge. The technology consists of screen-printed dry carbon electrodes on soft polyurethane substrate. Two dry electrode arrays were placed on the face: One array for bio-potential measurements to capture muscle activity and a second array for bio-impedance. For the bio-potential signals, independent component analysis (ICA) was used to differentiate different muscle activations. Four-contact bio-impedance measurements were used to extract changes (related to artery volume change), as well as beats per minute (BPM). We performed concurrent bio-potential and bio-impedance measurements in the face. From the simultaneous measurements we successfully captured fluctuations in the superficial temporal artery diameter in response to facial muscle activity, which ultimately changes blood flow. The observed changes in the face, following muscle activation, were consistent with measurements in the forearm and were found to be notably more intricate. Both at the arm and the face, a clear increase in the baseline impedance was recorded during muscle activation (artery narrowing), while the impedance changes signifying the pulse had a clear repetitive trend only at the forearm. These results reveal the direct connection between muscle activation and the blood vessels in their vicinity and start to unveil the complex mechanisms through which facial muscles might modulate blood flow and possibly affect human physiology.

Holistic Approach for Noninvasive Facial Rejuvenation by Simultaneous Use of High Intensity Focused Electrical Stimulation and Synchronized Radiofrequency: A Review of Treatment Effects Underlined by Understanding of Facial Anatomy

Understanding facial anatomy is a key aspect for successful treatment of age-related changes manifested to facial tissues. Namely, changes to the facial muscles and their connective tissue framework result in an increased soft tissue laxity, leading to wrinkling, sagging, and altered texture. This review elaborates on the use of novel high intensity focused electrical stimulation (HIFES) and Synchronized RF technology to improve facial muscle tone and skin structure, focusing on the technology background and clinical aspects.

Clinical validation of the upper face first principle-A clinical, prospective, interventional split-face study

BACKGROUND

Previous clinical and anatomic investigations have identified the clinical relevance of facial biomechanics. Based on this new understanding, principles for facial aesthetic procedures were established: Lateral Face First, Deep Layers First, and Upper Face First.

OBJECTIVE

To test the upper face first principle by showing that an injection sequence, starting in the upper face is superior to an injection sequence starting in the lower face.

METHODS

This study was designed as an interventional split-face study administering the same amount and type of soft tissue filler for the upper, middle, and lower face but in a different sequence: upper, middle, lower face versus lower, middle, and upper face. A total of 15 patients (5 males and 10 females) with a mean age of 39.4 years (9.6) and a mean BMI of 23.4 kg/m² (1.7) were studied. Follow-up at D0, D30, and D90 was conducted utilizing semiquantitative scores and objective 3D imaging.

RESULTS

Despite not reaching statistical significance, midfacial volume and jawline contouring were rated better at every follow-up visit (D0, D30, D90) when treated with the upper versus the lower face first injection algorithm. The global aesthetic improvement scale showed statistically significantly better values for the upper face first algorithm when compared to the lower face first algorithm at all evaluated time points with all p < 0.001.

CONCLUSION

Applying the upper face first injection algorithm seems to result in better aesthetic outcomes when directly compared to the lower face first algorithm. Semiquantitative and objective outcome measurements confirm its clinical effectiveness.

'Valves' of the angular vein: Orbicularis oculi, depressor supercilii, and zygomaticus minor

OBJECTIVES

The aim of this study was to elucidate the positional relationship between the courses of the angular veins and the facial muscles, and the possible roles of the latter as alternative venous valves.

METHODS

The angular veins of 44 specimens of embalmed Korean adult cadavers were examined. Facial muscles were studied to establish their relationships with the angular vein, including the orbicularis oculi (OOc), depressor supercilii (DS), zygomaticus minor (Zmi), zygomaticus major (Zmj), and levator labii superioris (LLS).

RESULTS

In the upper face of all specimens, the angular vein passed through the DS and descended to the medial palpebral ligament. In the midface, it passed between the origin of the levator labii superioris alaeque nasi (LLSAN) and the inferior OOc fibers. The vein coursed along the deep surface of the inferior margin of the OOc in all specimens. At the level of the nasal ala, the course of the angular vein was classified into three types: in type I it passed between the LLS and Zmi (38.6%), in type II it passed between the superficial and deep fibers of the Zmi (47.7%), and in type III it passed between the Zmi and Zmj (13.6%). In the lower face of all specimens, the angular or facial vein passed through the anterior lobe of the buccal fat pad.

CONCLUSION

This study found that the angular vein coursed along the sites where facial muscle contractions are assumed to efficiently compress the veins, likely controlling venous flow as valves. The observations made and analysis performed in this study will improve the understanding of the physiological function of the facial muscles as alternative venous valves.

Real-Time Ultrasound Imaging of the Tear Trough: Lessons Learned From Functional Anatomy

BACKGROUND

The tear trough is one of the most challenging facial regions for soft-tissue filler injections. A thorough understanding of the underlying facial, muscular, and vascular anatomy is crucial to perform safe and effective tear trough injectable treatments.

OBJECTIVES

The authors sought to evaluate the location and function of the angular vein in the tear trough in 3 different facial expressions: repose, smiling, and max. orbicularis oculi contraction.

METHODS

Twenty study participants with a mean age of 48.3 years and mean BMI of 24.5 kg/m2 were investigated via functional ultrasound imaging. The diameter of the angular vein and the velocity and direction of venous blood flow were analyzed in repose, smiling, and during max. orbicularis oculi contraction.

RESULTS

The angular vein was identified in 100% of the cases to travel inside the orbicularis oculi muscle (intra-muscular course) within the tear trough, whereas the angular artery was not identified in this location. The distance between the angular vein and the inferior orbital rim was (lateral to medial): 4.6 mm, 4.5 mm, 3.9 mm, and 3.8 mm. The caudally directed blood flow was in repose 10.2 cm/s and was 7.3 cm/s at max. orbicularis oculi muscle contraction; however, no blood flow was detectable during smiling.

CONCLUSIONS

The diameter and the venous blood flow of the angular vein varied between the 3 tested facial expressions. Based on these anatomical findings, the deep injection approach to the tear trough is recommended due to the intramuscular course of the angular vein.

Soft tissue filler augmentation of the orbicularis retaining ligament to improve the lid-cheek junction

BACKGROUND

The orientation of facial ligaments changes with increasing age due to the loss of bony support. Soft tissue filler injections placed in close proximity to facial ligaments can alter their orientation to help achieve an improved and younger aesthetic appearance.

OBJECTIVE

To assess the anatomic and aesthetic effects of a standardized injection with soft tissue filler placed directly inferior to the orbicularis retaining ligament in the infraorbital region.

METHODS

A total of 163 patients with signs of infraorbital aging were treated with a standardized soft tissue filler injection into and in close proximity to the orbicularis retaining ligament (ORL). 2D frontal images of the infraorbital region were rated by eleven blinded and independent raters with regards to the aesthetic appearance of the infraorbital region before and after the standardized injection treatment.

RESULTS

The aesthetic appearance of the entire infraorbital region (lid-cheek junction) was rated before and after the treatment. The severity of the tear trough (medial aspect of the infraorbital region) as well as the hollowing of the lateral aspect of the infraorbital region also was rated before and after the treatment. Aesthetic improvement was statistically significant when evaluated by the blinded raters, the treating physician, and the patients. All the results were "very much improved" compared to baseline.

CONCLUSION

The effectiveness of this injection technique is thought to be due to the strategic placement of soft tissue filler that helps to reposition facial ligaments that have changed their orientation during the aging process.

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.

The mobility of the superficial and deep midfacial fat compartments: An ultrasound-based investigation

BACKGROUND

Understanding the mobility of the midface and the separate contributions of the superficial and deep fat compartments is essential for natural esthetic outcomes following soft tissue filler or fat grafting procedures. A study was designed that used ultrasound imaging to demonstrate in vivo visualization and quantification of distances and movements in the midface.

METHODS

A total of 48 midfaces of 24 healthy Caucasian volunteers, all naïve of esthetic procedures, (22 females; 46.85 (9.8) years; 22.83 (3.1) kg/m² ) were scanned using 18 MHz ultrasound imaging. Distances between bony landmarks (inferior orbital rim, infraorbital foramen) were used as markers to measure the cranial movement of the superficial (superficial nasolabial and superficial medial cheek fat compartment) and the deep (deep pyriform space, deep medial check fat compartment, deep lateral cheek fat compartment) midfacial fat compartments between resting and smiling facial position.

RESULTS

The superficial midfacial fat compartment moved, on average, 3.7 mm (p < 0.001) cranially, whereas the deep midfacial fat compartments moved, on average, 0.1 mm (p > 0.05) during smiling. No gender differences in mobility were identified (p > 0.05).

CONCLUSION

The results obtained are in line with previous cadaveric investigations and revealed, in a highly statistically significant fashion, that the superficial midfacial fat compartments move in cranial direction whereas the deep fat compartment did not display similar positional changes. These results help to guide facial injectable treatments and to understand why, in the midface, a deep supraperiosteal approach should be favored when augmenting the deep midfacial fat compartments.