Clinical implications of the arterial supplies and their anastomotic territories in the nasolabial region for avoiding arterial complications during soft tissue filler injection.

INTRODUCTION: The nasolabial fold (NLF) causes particular concern during aging in the middle face region. However, arterial complications of filler injections at this site have been continually reported during recent years. The aim of this study was to investigate the arterial locations and their anastomotic pathways related to filler injection sites in the NLF. MATERIALS AND METHODS: Thirty hemi-faces of 15 embalmed Thai cadavers were dissected. Three anatomical landmarks of NLFs were assigned: the inferior margin level (NLF1), the mid-philtral horizontal line level (NLF2), and the inferior alar level (NLF3). Ten hemi-faces of five soft embalmed Thai cadavers underwent a modified Sihler's staining procedure to investigate the arterial anastomoses. RESULTS: The artery closest to all of the landmarks was the facial artery. It was located inferomedial to NLF1 in 28%, and the mean distances along the X- and Y-axes were 3.53 ± 2.11 mm and 3.53 ± 1.75 mm, respectively. It was also located medial to NLF2 in 52.1% with an X-axis distance of 4.93 ± 1.53 mm. Several arteries were located close to NLF3, including the facial (33.3%), lateral nasal (33.3%), and infraorbital (30.0%) arteries. Anastomoses of the nasolabial arteries served to connect both the external-external and internal-external carotid systems. CONCLUSIONS: Several arteries are located close to NLF1-NLF3. To prevent arterial injury, the locations and anastomotic pathways, as possible sources of severe complications, should be recognized prior to NLF filler injection.

Anatomical and Ultrasonography-Based Investigation to Localize the Arteries on the Central Forehead Region During the Glabellar Augmentation Procedure.

Glabellar augmentation is one of the most popular cosmetic procedures but can entail severe complications caused by inadvertent intravascular injection of filler. Nevertheless, few studies have investigated the arteries on the glabellar and central forehead regions. The aim of this study was to correlate the topography and location of the arteries in this area with anatomical landmarks to propose a safety guideline. Two methods were used to investigate the glabellar and central forehead areas: dissection of 19 Thai embalmed cadavers, and ultrasonographic examination of 14 healthy Thai volunteers. At the level of the glabellar point, the horizontal distances from the midline to the arteries were 4.7 mm (central artery), 7.8 mm (paracentral artery), and 14.7 and 19.2 mm (superficial and deep branches of supratrochlear artery). The depths from the skin of the arteries were 3.1 mm (central artery), 4.8 mm (paracentral artery), and 4.2 and 5.9 mm (superficial and deep branches of supratrochlear artery). The periosteal artery was detected in 71.1% as a branch of either the superior orbitoglabellar or the supratrochlear artery. It ran in the supraperiosteal layer for a short course and penetrated the periosteum above the superciliary ridge or above the medial eyebrow, adhering tightly to the bony surface. This study suggests a safe injection technique for the glabella based on a thorough knowledge of arterial distribution and topography and color Doppler ultrasonographic examination prior to the injection, which is recommended to minimize the risk of severe complications. Clin. Anat. 33:370-382, 2020. © 2019 Wiley Periodicals, Inc.

Safe Planes for Injection Rhinoplasty: A Histological Analysis of Midline Longitudinal Sections of the Asian Nose.

BACKGROUND: Dorsal nasal augmentation is an essential part of injection rhinoplasty on the Asian nose. Aesthetic physicians require detailed knowledge of the nasal anatomy to accurately and safely inject filler. METHODS: One hundred and thirty-five histological cross sections were examined from 45 longitudinal strips of soft tissue harvested from the midline of the nose, beginning from the glabella to the nasal tip. Muscles and nasal cartilage were used as landmarks for vascular identification. RESULTS: At the nasal tip, a midline longitudinal columellar artery with a diameter of 0.21 ± 0.09 mm was noted in 14 cadavers (31.1 %). At the infratip, subcutaneous tissue contained cavernous tissue similar to that of the nasal mucosa. The feeding arteries of these dilated veins formed arteriovenous shunts, into which retrograde injection of filler may be possible. All of the nasal arteries present were identified as subcutaneous arteries. They coursed mainly in the superficial layer of the subcutaneous tissues, with smaller branches forming subdermal plexuses. A substantial arterial anastomosis occurred at the supratip region, in which the artery lay in the middle of the subcutaneous tissue at the level of the major alar cartilages. These arteries had a diameter ranging between 0.4 and 0.9 mm and were found in 29 of 45 specimens (64.4 %). This was at the level midway between the rhinion above the supratip and the infratip. This anastomotic artery also crossed the midline at the rhinion superficial to the origin of the procerus on the lower end of the nasal bone. Here the arterial diameter ranged between 0.1 and 0.3 mm, which was not large enough to cause arterial emboli. Fascicular cross sections of the nasalis muscle directly covered the entire upper lateral cartilage. The subdermal tissue contained few layers of fat cells along with the occasional small artery. The procerus arose from the nasal bone and was continuous with the nasalis in 16 cadavers (35.6 %). There was fatty areolar tissue between the procerus and the periosteal layer and no significant arteries present. The procerus ascended beyond the brow to insert into the frontalis muscle with very few cutaneous insertions. The supratrochlear vessels and accompanying nerve were occasionally found on the surface of the frontalis muscle. CONCLUSION: Most nasal arteries found in the midline are subcutaneous arteries. Filler should be injected deeply to avoid vascular injury leading to compromised perfusion at the dorsum or filler emboli at the nasal tip. LEVEL OF EVIDENCE V: This journal requires that the 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.

Anatomical knowledge of zygomatico-buccal plexus in a cadaveric study.

The details of the facial nerve pattern were clearly explained in the parotid gland (PG), lateral area of the face, and periorbital areas to prevent the unexpected outcome of medical intervention. However, it remains unclear whether information about the zygomatico-buccal plexus (ZBP) in the masseteric and buccal regions. Therefore, this study aimed to help clinicians avoid this ZBP injury by predicting their common location. This study was conducted in forty-two hemifaces of twenty-nine embalmed cadavers by conventional dissection. The characteristics of the buccal branch (BB) and the ZBP were investigated in the mid-face region. The results presented that the BB gave 2-5 branches to emerge from the PG. According to the masseteric and buccal regions, the BB were arranged into ZBP in three patterns including an incomplete loop (11.9%), a single-loop (31.0%), and a multi-loop (57.1%). The mean distance and diameter of the medial line of the ZBP at the corner of the mouth level were 31.6 (6.7) and 1.5 (0.6) mm respectively, while at the alar base level were 22.5 (4.3) and 1.1 (0.6) mm respectively. Moreover, the angular nerve arose from the superior portion of the ZBP at the alar base level. The BB formed a multiloop mostly and showed a constant medial line of ZBP in an area approximately 30 mm lateral to the corner of the mouth, and 20 mm lateral to the alar base. Therefore, it is recommended that physicians should be very careful when performing facial rejuvenation in the mid-face region.

Lower Nose Arterial Plexus and Implications for Safe Filler Injections.

BACKGROUND: The lower nose has abundant blood supply; however, nasal tip necrosis still occurs following filler injections. This study revealed the complicated pattern of the arterial supply of the lower nose. METHODS: The arterial pattern of the lower nose was studied in 40 cadavers using conventional dissections and translucent modified Sihler staining. RESULTS: Two arterial rings were connected in a figure of eight. The upper ring (nasal arterial circle) consisted of the lateral nasal and the subalar arteries encircling the nasal tip and alae. The lower ring (arterial plexus of the upper lip) was more important because of the contribution of the facial and superior labial arteries. This specific feature had not been mentioned elsewhere. CONCLUSION: Understanding this specific feature of the blood supply of the lower nose is essential for aesthetic physicians to perform the appropriate techniques during filler injection procedures in the nasal and perioral regions.

The Crest Injection Technique for Glabellar Line Correction and the Paracentral Artery.

The glabella is a zone that carries a high risk of blindness after performing filler injections. The arteries beneath the glabellar lines were investigated by meticulous dissections in 30 geriatric embalmed cadavers with latex injections into the arterial system. The results showed that the supratrochlear artery, a direct branch of the ophthalmic artery, ascended from the muscular layer of the medial eyebrow along the medial canthal vertical line of the intercanthal vertical zone (53 in 60 hemifaces, or 88%). The dominant single paracentral artery from the radix artery was found within the radix vertical zone (eight out of 30 glabellae, or 27%). Among these, the dominant paracentral artery was near the midline in two cadavers and arose along the radix vertical line in six cadavers. The dominant paracentral artery may be the cause of ocular complications during injections of glabellar lines between the medial eyebrows, especially at the radix vertical lines. The supratrochlear artery might cause ocular complications when an injection is performed close to the medial eyebrows. Pinching to create a skin crest and evert glabellar line for a precise injection is recommended to temporarily occlude the paracentral artery.

Anatomical Study of the Dorsal Nasal Artery to Prevent Visual Complications during Dorsal Nasal Augmentation.

Dorsal nasal augmentation is a common injection associated with ocular complications. Digital compressions on both sides of the nose are recommended during injection. Considering the reported incidences of visual complications, this preventive technique may need an adjustment for more effectiveness to prevent blindness. Therefore, the dorsal nasal arteries (DNAs) were studied by conventional dissections in the subcutaneous and fibromuscular tissues of the nasal dorsum in 60 embalmed cadavers. The results showed that among the 60 faces, 32 faces had bilateral DNAs (53.3%), 23 had dorsal nasal plexus with minute arteries (38.3%), and five had a single dominant DNA (8.3%). The DNA originated from one of the four arterial sources, which influenced the location and course of the artery. These sources included the ophthalmic angular arteries in 21 faces (56.8%), terminal ophthalmic arteries in two faces (5.4%), lateral nasal arteries in 11 faces (29.7%) and facial angular arteries in three faces (8.1%). Consequently, the dominant dorsal nasal artery running close to the midline found in 8% of the cases could make side compressions during nasal dorsum augmentation less effective from preventing ocular complications. However, an adjustment of digital compressions which combines pinching and side compressions is suggested to improve the safety.

Achieving the Most Effective Hanging Points at the Lower End of the Face for Thread Lifting: Quantitative Measurement of Tissue Resistance in Different Facial Layers.

The thread lift procedure is a minimally invasive alternative to facelift surgery. The hanging point, which the terminal end of the thread is hooked into, is an important component. If it is loose and cannot stabilize the passage when the inserted thread is pulled, the lifting effect will fail. Therefore, the aim of this study was to elucidate the ability of the tissue to support the thread attachment in the different facial layers while performing this procedure. Twenty hemi-faces of 10 soft cadavers, which were divided into 45 blocks, were used to measure the tissue resistance in the midface area. The resistance of the soft tissue in the four facial layers in each block was measured while a 22G cannula connected with a force gauge was passed through it. The results showed that the tissue resistance in the sub-SMAS was higher than the SMAS and subcutaneous layers in the blocks located in the nasolabial and perioral regions. This was also significantly greater than the resistance in the subcutaneous layer in the three medial blocks below the oral commissure (P < 0.05). However, the low resistance of the sub-SMAS was found in the blocks located in the buccal and lower parotidomasseteric regions. Thus, it was preferable that the hanging point was based in the deep plane (sub-SMAS and SMAS layers) of the nasolabial, perioral, and upper parotidomasseteric regions. Moreover, the sub-SMAS layer within the buccal and lower parotidomasseteric regions should be avoided due to the loose attachment in the buccal capsule and subplatysmal fat.

The Feasibility Determination of Risky Severe Complications of Arterial Vasculature Regarding the Filler Injection Sites at the Tear Trough.

BACKGROUND: The tear trough is a significant sign of periorbital aging and has usually been corrected with filler injection. However, the arterial supply surrounding the tear trough could be inadvertently injured during injection; therefore, this study aimed to evaluate the nearest arterial locations related to the tear trough and investigate the possibility of severe complications following filler injection. METHODS: Thirty hemifaces of 15 Thai embalmed cadavers were used in this study. RESULTS: The artery located closest to both the inferior margin (TT1) and mid-pupil level (TT2) of the tear trough was found to be the palpebral branch of the infraorbital artery. Furthermore, at 0.5 mm along the tear trough from the medial canthus (TT3), the angular artery was identified, which was found to be a branch of the ophthalmic artery. The artery at TT1 and TT2 was located beneath both the zygomaticus major and the orbicularis oculi muscles. The distances from TT1 to the artery were measured as follows: laterally, 2.79 ± 1.08 mm along the x axis; and inferiorly, 2.88 ± 1.57 mm along the y axis. For the TT2, the artery was located inferomedially from the landmark of 4.65 ± 1.83 mm along the x axis and 7.13 ± 3.99 mm along the y axis. However, the distance along the x axis at TT3 was located medially as 4.00 ± 2.37 mm. CONCLUSION: The high risk of injury to the artery at the tear trough should be considered because of the numerous arteries to this area.