External and Internal Diameters of the Facial Artery Relevant to Intravascular Filler Injection:

Three-Dimensional Location of the Facial Artery in Relation to the Nasolabial Fold in Asian People: A Cadaveric CTA Study

BACKGROUND

Injection cosmetics have become popular in recent years. The nasolabial fold is one of the most important and dangerous regions in the midface, and its three-dimensional relationship with the facial artery remains unclear.

METHODS

Fifty-two cadavers infused with lead oxide contrast medium via the external carotid arteries were scanned by computed tomography (CT). The three-dimensional model was reconstructed using Mimics and Origin software, and the relevant data were calculated using validated algorithms.

RESULTS

There were three facial artery types according to its course in relation to the nasolabial fold. In the most common type, accounting for 83.7% of specimens, the facial artery evolves into an angular artery, with a horizontal distance between facial artery and nasolabial fold of - 1.90 ± 2.40, - 3.90 ± 2.95, - 5.18 ± 3.42, - 5.59 ± 3.53, - 5.59 ± 3.83, - 6.07 ± 4.10, - 6.92 ± 3.70, - 6.79 ± 3.37, - 4.52 ± 3.20, and - 2.76 ± 3.60 (mm) from the nasal ala to the oral commissure and a vertical distance of - 4.03 ± 2.56, - 3.27 ± 2.27, - 2.81 ± 2.57, - 2.1 ± 2.64, - 1.5 ± 3.32, - 0.71 ± 3.99, 0.92 ± 4.43, 0.4 ± 5.31, - 4.14 ± 5.14, - 7.05 ± 4.74 (mm).

CONCLUSIONS

The facial artery is vulnerable to damage when injecting filler in the nasolabial fold. For the upper 1/3 of the nasolabial fold, the supraperiosteal layer is recommended for injection, while for the lower 2/3 of the nasolabial fold, the dermal layer along the nasolabial fold is recommended.

LEVEL OF EVIDENCE IV

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Consideration of the diameter of superficial temporal arteries related to filler injections in the temporal region

BACKGROUND

The concavity of the temple due to adipose tissue atrophy from aging accentuates the zygomatic arch and lateral orbital rim, leading to an aged appearance. The use of hyaluronic acid filler in the temporal region has gained popularity due to its procedural simplicity and consistent outcomes.

OBJECTIVE

To evaluate the safety of administering hyaluronic acid filler in the temporal region concerning the frontal branch of the superficial temporal artery, which is at risk of injury.

METHODS

Empirical observations were conducted on the internal diameter of the frontal branch of the superficial temporal artery, a critical anatomical site for potential injury.

RESULTS

A significant proportion of the artery segments exhibited an internal diameter below 1 mm. Given that the outer diameter of an 18-gauge cannula is 1.27 mm, this method can be considered a relatively secure approach for enhancing the temporal region.

CONCLUSION

The use of an 18-gauge cannula for hyaluronic acid filler administration in the temporal region appears to be a safe and effective method, with the potential risk to the frontal branch of the superficial temporal artery being minimal.

Why Do Nasolabial Folds Appear? Exploring the Anatomical Perspectives and the Role of Thread-Based Interventions

The classification of nasolabial folds into three types, each with distinct causative factors and mechanisms, is explored. Age-related changes in facial skin and connective tissues are examined in detail, revealing variations across different facial regions due to variances in tissue firmness and thickness. The innovative 'Reverse Technique,' involving cog threads to enhance tissue traction and effectiveness in thread-lifting procedures, is introduced. Detailed technical guidelines, anatomical considerations, and safety measures are provided, emphasizing the importance of identifying optimal vectors and fixing points to achieve maximum lifting effects while minimizing potential risks, particularly those associated with vascular structures. Additionally, the 'Cross Technique using volumizing thread' is discussed, designed to smooth tissue boundaries and rejuvenate sagging areas. Facial anatomy, including the positioning of arteries and ligaments, is underscored as essential for ensuring the safety and efficacy of procedures. In conclusion, this review stands as a comprehensive guide for practitioners, offering insights into innovative thread-lifting methods and their applications in addressing nasolabial folds. The primary focus is on achieving optimal aesthetic results while prioritizing patient safety.

Analysis of Age-Related Changes in Lower Facial Fat Compartments and of the Course of Blood Vessels Using Computed Tomography

BACKGROUND

According to the volume restoration theory, lower facial fat compartments tend to selectively atrophy or hypertrophy with age. The aim of this study was to demonstrate age-related changes in lower facial fat compartments using computed tomography, with strict control of the body mass index and underlying diseases.

METHODS

This study included 60 adult women in three age-based categories. The thicknesses of the jowl, labiomandibular, and chin fat compartments were measured using computed tomographic images. The distribution and arrangement of facial blood vessels were further analyzed to provide evidence of the safety of rejuvenation strategies based on the facial volumetric theory.

RESULTS

The inferior part of the superficial jowl fat compartment and deep jowl fat compartment thickened with age. The deep layer of the labiomandibular fat compartment thinned with age, and the superficial layer thickened with age. The deep and superficial layers of the chin compartments thickened with age. The facial vein passes through the lower mandibular border at the anterior edge of the masseter muscle and moves upward, perpendicular to the lower mandibular border. The high-risk area of the facial artery had an angle of approximately 45 degrees to the lower mandibular border.

CONCLUSIONS

This study suggests that with age, selective thickening or thinning occurs in different lower facial fat compartments. The mandible and masseter muscle were used as reference markers to analyze the courses of the facial artery and facial vein, which can help clinicians to reduce vascular injury.

Inverted gracilis muscle free flap with intraoral vascular anastomoses for facial reanimation in vessel depleted neck: A case report

The reinnervated gracilis muscle free flap represents a workhorse of facial reanimation. This procedure is carried out secondarily to parotid resections, due to advanced tumors that spread to the surrounding structures. Finding recipient vessels might be problematic if other reconstructive procedures are needed to address the defects. This paper describes a procedure to inset a reinnervated gracilis muscle free flap in a vessel depleted patient, through intraoral anastomoses to avoid venous interposition grafts. A 52-year-old man developed an advanced adenocarcinoma of the deep parotid lobe and underwent radical surgical excision including the mandibular ramus, condyle, and facial soft tissues (defect size: 8 cm × 4 cm). A secondary double-flap reconstruction restored the mandibular defect and inset a cross-face nerve graft. A third intervention finalized the facial reanimation with a 10 cm reinnervated gracilis muscle free flap. The gracilis flap inset was inverted resulting in the proximal flap (pedicle side) lying on the buccal aspect. This allowed vessel joining from the contralateral side via intraoral anastomoses. No complications occurred within and after the intervention. However, the adenocarcinoma relapsed before reinnervation of the gracilis. The patient also had distant brain and lung metastases and received best supportive care. The inverted gracilis muscle free flap may represent an option for attaining facial reanimation in vessel-depleted patients avoiding long interposition venous grafts.

Is constant needle motion during soft tissue filler injections a safer procedure? A theoretical mathematical model for evaluating patient safety

BACKGROUND

The safety rationale behind the constant needle motion injection technique is based on the assumption that due to the constant needle motion and simultaneous soft tissue filler material administration a smaller amount of product per area may be injected into an artery if an artery within the range of the moving needle is inadvertently entered.

OBJECTIVE

To perform mathematical calculations for determining the probability for causing intra-arterial product administration when constantly moving the needle during facial aesthetic soft tissue filler injections.

METHODS

This study was designed as a theoretical investigation into the probabilities for causing adverse events due to intravascular injection of soft tissue filler material when constantly moving a 27-G needle during facial soft tissue filler administration.

RESULTS

It was revealed that with a higher number of conducted injection passes a greater soft tissue area can be covered by the needle. The odds of encountering an artery within the covered soft tissue volume and the odds of injecting any volume greater than zero into the arterial blood stream increases with the number of performed injection passes. This increase is greatest between 1 and 10 performed injection passes.

CONCLUSION

This model demonstrates that the constant needle motion technique increases the probability of encountering an artery within the treatment area and thus increases the odds for intra-arterial product administration. The constant needle motion technique does not increase safety but rather may increase the odds of causing intra-arterial product administration with the respective adverse consequences for the patient.

Diversity of the free helical rim flap: A case series tailoring the microsurgical technique to esthetically optimize full-thickness nasal defect reconstructions

INTRODUCTION

The free helical rim (FHR) flap offers like-with-like reconstruction for full-thickness nasal defects. A case series of nasal reconstruction using an FHR flap was presented, detailing surgical steps and refinements, as well as functional and esthetic outcomes.

METHODS AND MATERIALS

This is a retrospective cohort study of composite nasal defect reconstruction with FHR flap from August 2018 to March 2020. Descriptive data were analyzed by SPSS software.

RESULTS

Six cases were recruited, four were unilateral alar defects, one was hemi-nose, and one was ala plus tip. The average size of the defect was 2.5 × 2.8 cm2. Three FHR flaps were designed with retrograde pedicles and three with anterograde pedicles. The facial artery and veins were the recipient vessels in all cases. Vascular grafts were used in all six cases. Descending branch of the lateral circumflex femoral (DLCxF) artery and vein functioned as interposition vascular conduits in five cases. Superficial forearm vein grafts were used in one case. One patient needed flap re-exploration due to venous congestion. One patient had partial flap necrosis due to delayed infection, and one developed delayed wound dehiscence in the irradiated wound. The average follow-up was 18 months.

CONCLUSION

The FHR flap has consistent vascular anatomy. It can be raised as an anterograde or retrograde flap for a contralateral or ipsilateral inset. FHR flap can be used in extensive composite nasal defects. This case series demonstrates that interposition vascular grafts are invariably needed and the possibility of using forearm vessels as grafts instead of DLCxF artery and vein.

Vascular complications with necrotic lesions following filler injections: Literature systematic review

INTRODUCTION

Although the related risk of vascular necrosis due to filler injection is low, the outcomes can be severe when they occur. This systematic review aims to report the occurrence and treatment of vascular necrosis due to filler injection.

MATERIALS AND METHODS

The systematic review was performed according to PRISMA guidelines.

RESULTS

The results showed the most used treatment is a combination of pharmacologic therapy and hyaluronidase application, which is efficacy when applied in the first 4 h. In addition, even though management recommendations are available in literature, proper guidelines are unavailable due to the low number of complications occurrence.

CONCLUSION

Clinical and high-quality studies on treatment and management of filler injection combination are necessary to provide scientific evidence on what to do in case of vascular complication occurrence.

Bridging a Century-Old Problem: The Pathophysiology and Molecular Mechanisms of HA Filler-Induced Vascular Occlusion (FIVO)—Implications for Therapeutic Interventions

Biocompatible hyaluronic acid (HA, hyaluronan) gel implants have altered the therapeutic landscape of surgery and medicine, fostering an array of innovative products that include viscosurgical aids, synovial supplements, and drug-eluting nanomaterials. However, it is perhaps the explosive growth in the cosmetic applications of injectable dermal fillers that has captured the brightest spotlight, emerging as the dominant modality in plastic surgery and aesthetic medicine. The popularity surge with which injectable HA fillers have risen to in vogue status has also brought a concomitant increase in the incidence of once-rare iatrogenic vaso-occlusive injuries ranging from disfiguring facial skin necrosis to disabling neuro-ophthalmological sequelae. As our understanding of the pathophysiology of these injuries has evolved, supplemented by more than a century of astute observations, the formulation of novel therapeutic and preventative strategies has permitted the amelioration of this burdensome complication. In this special issue article, we review the relevant mechanisms underlying HA filler-induced vascular occlusion (FIVO), with particular emphasis on the rheo-mechanical aspects of vascular blockade; the thromboembolic potential of HA mixtures; and the tissue-specific ischemic susceptibility of microvascular networks, which leads to underperfusion, hypoxia, and ultimate injury. In addition, recent therapeutic advances and novel considerations on the prevention and management of muco-cutaneous and neuro-ophthalmological complications are examined.

The Usefulness of Magnetic Resonance Angiography to Analyze the Variable Arterial Facial Anatomy in an Effort to Reduce Filler-Associated Blindness: Anatomical Study and Visualization Through an Augmented Reality Application

BACKGROUND

The use of soft tissue fillers for facial rejuvenation is increasing rapidly and the complications, unfortunately, follow the same path. Blindness caused by intravascular filler injections is a rare but devastating complication. Knowledge of the individual arterial anatomy may aid the injector in avoiding injecting into an artery and thus to prevent blindness.

OBJECTIVES

To evaluate if the use of magnetic resonance angiography (MRA) may visualize the arterial facial anatomy in a contrast- and radiation-free way and study the individual arterial variations using an augmented reality (AR) image.

METHODS

The individual arterial anatomy of the 3 terminal branches of the ophthalmic artery (supraorbital [SO]; supratrochlear [STr]; and dorsal nasal [DN] arteries) of 20 volunteers was studied by a 3-Tesla MRI, combining infrared (IR) facial warming and 3-dimensional time-of-flight multiple overlapping thin slab acquisition MRA. The resulting visualization of the facial arteries was shown on the patient's face through AR technology.

RESULTS

The MRA was able to visualize the SO in 90.0%, STr in 92.5%, and DN arteries in 75% of the examined patients, as well as numerous variations in both vessel localization and path. Furthermore, a proof-of-concept of the AR visualization of the individual arterial anatomy was successfully implemented.

CONCLUSIONS

Dermal filler injectors should be aware of the risk of filler-induced blindness and familiarize themselves with the visualization of the variable facial vascular anatomy. The implementation of a one-time MRA and subsequent AR visualization may be useful in the accurate planning of minimally invasive facial rejuvenation procedures.

An Anatomical Guide to the Terminal Facial Artery: Lumen Diameter and Associated Anatomy Relevant to Dermatologic Procedures

BACKGROUND

Dermal filler injection in the vicinity of the terminal facial artery (FA) can lead to vascular compromise with devastating consequences, including tissue necrosis, blindness, and stroke.

OBJECTIVE

The purpose of this study was to examine lumen diameter and other anatomical features of the terminal FA relevant to dermal filler injection.

MATERIALS AND METHODS

Eighteen embalmed adult cadavers were dissected along the distribution of the terminal FA. Gross and microscopic measurements were taken at predetermined points in its course.

RESULTS

Mean lumen diameter was largest at the midpoint between the oral commissure and the lateral supra-alar crease (0.81 ± 0.36 mm; point P1) and smallest at the midpoint between the lateral supra-alar crease and the medial canthus (0.43 ± 0.23 mm; point P3). Mean cutaneous depth was deepest at the lateral supra-alar crease (5.06 ± 1.84 mm; point P2) and most superficial at the midpoint between the lateral supra-alar crease and the medial canthus (3.13 ± 2.07 mm; point P3).

CONCLUSION

The large-caliber lumen diameter of the terminal FA creates the potential for intra-arterial injection with commonly used filler needles and blunt-tipped cannulas at all points in its course in the nasolabial fold and midface.

Topographic Anatomy of the Zygomatico-Orbital Artery: Implications for Improving the Safety of Temporal Augmentation

BACKGROUND

Anatomical knowledge of the zygomatico-orbital artery and its most relevant clinical applications is essential for ensuring the safety of filler injection into the temporal region. The purpose of this study was to provide the precise position, detailed course, and relationship with surrounding structures of the zygomatico-orbital artery.

METHODS

Fifty-eight patients who underwent head contrast-enhanced three-dimensional computed tomography and 10 fresh frozen cadavers were investigated.

RESULTS

The zygomatico-orbital artery was identified in 93 percent of the samples in this work. Ninety-four percent of the zygomatico-orbital arteries derived directly from the superficial temporal artery, and the remaining arteries started from the frontal branch of the superficial temporal artery. According to the origin of the zygomatico-orbital artery, it was classified into type I and type II. Type I arteries were then classified into three subtypes. The trunk of the zygomatico-orbital artery was located between the deep temporal fascia and the superficial temporal fascia. Deep branches of the zygomatico-orbital artery pierced the superficial layer of the deep temporal fascia. The zygomatico-orbital artery originated from 11.3 mm in front of the midpoint of the apex of the tragus, and most of its trunks were located less than 20.0 mm above the zygomatic arch. The mean diameter of the zygomatico-orbital artery was 1.2 ± 0.2 mm. There were extensive anastomoses between the zygomatico-orbital artery and various periorbital arteries at the lateral orbital rim.

CONCLUSION

The precise anatomical knowledge of the zygomatico-orbital artery described in this study could be helpful for cosmetic physicians for improving the safety of temporal augmentation.

Transverse facial artery: Its role in blindness after cosmetic filler and botulinum toxin injections

Masseter injections for cosmetic or pathological reasons are increasingly common, as are filler injections using dual or multiplane techniques in the lateral facial regions or for jawline contouring. The occurrence of blindness following these procedures often remains unexplained. This study aimed to determine the anatomical explanation for this debilitating complication by investigating the transverse facial artery and its relation to the masseter. For this purpose, we dissected 35 cheek specimens with latex injections and 10 specimens without latex. The external carotid artery was dissected up to its bifurcation into the maxillary and superficial temporal arteries. Results showed that the transverse facial artery arose from the superficial temporal or external carotid artery that runs between the zygomatic arch and the parotid duct. Three types of transverse facial arteries were observed: type I: a short artery that did not extend beyond the masseter muscle; type II: a transverse artery that ran to the nasolabial fold and anastomosed to the facial artery; and type III: a sizable transverse artery that substituted the hypoplastic facial artery, continued as the angular artery, and then anastomosed to the dorsal nasal artery. Knowledge of these three types of transverse facial arteries is a prerequisite to study the vascular territory. Type III provides an explanation for the occurrence of blindness after lateral face injections. We consequently define a line that runs from the tragus to the outer quarter of the upper lip as the risk area, while the safe zone is located on either side of this line.