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.

A Cadaveric Study of Dye Spreading: Determining the Ideal Injection Pattern for Masseter Hypertrophy.

BACKGROUND: Masseter hypertrophy is the main cause of an asymmetrical and squared lower facial contour in the Asian community. Botulinum toxin injection technique is crucial to treat this condition. OBJECTIVE: To improve injection techniques for masseter hypertrophy by elucidating the distribution of the injections within the masseter. METHODS: Thirty masseter muscles were divided into 6 groups of 5 muscles each. Each group received one 0.2- or 0.3-mL injection at Point A, B, or C according to a three-point technique. Muscle dimensions and dye of the primary and secondary dye spreading were measured. RESULTS: The average muscle length, width, and thickness were 69.87, 33.50, and 11.23 mm, respectively. The average primary longitudinal and horizontal spreading was 36.56 and 15.60 mm, respectively. No statistically significant difference was found between 0.2- and 0.3-mL injections at each point. CONCLUSION: The three-point technique best fits in the safe zone and should be the standard injection technique for masseter hypertrophy. Injection at Points B and C may create secondary spreading that affect the risorius muscle and the parotid gland which are the cause of asymmetrical smiling and xerostomia, respectively. The dosage should be adjusted according to the muscle volume and not only the thickness.

The analgesic efficacy of anterior femoral cutaneous nerve block in combination with femoral triangle block in total knee arthroplasty: a randomized controlled trial.

BACKGROUND: Ultrasound-guided femoral triangle block (FTB) can provide motor-sparing anterior knee analgesia. However, it may not completely anesthetize the anterior femoral cutaneous nerve (AFCN). We hypothesized that an AFCN block (AFCNB) in combination with an FTB would decrease pain during movement in the immediate 12 h postoperative period compared with an FTB alone. METHODS: Eighty patients scheduled to undergo total knee arthroplasty were randomized to receive either FTB alone (FTB group) or AFCNB with FTB (AFCNB + FTB group) as part of the multimodal analgesic regimen. The primary outcome was pain during movement at 12 h postoperatively. Secondary outcomes included numeric rating scale (NRS) pain scores, incidence of surgical incision site pain, intravenous morphine consumption, immediate functional performance, patient satisfaction, and length of hospital stay. RESULTS: The NRS pain scores on movement 12 h postoperatively were significantly lower in the AFCNB + FTB group than in the FTB group (mean difference: -2.02, 95% CI: -3.14, -0.89, P < 0.001). The incidence of pain at the surgical incision site at 24 h postoperatively and morphine consumption within 48 h postoperatively were significantly lower (P < 0.001), and quadriceps muscle strength at 0° immediately after surgery was significantly greater in the AFCNB + FTB group (P = 0.04). CONCLUSIONS: The addition of ultrasound-guided AFCNB to FTB provided more effective analgesia and decreased opioid requirement compared to FTB alone after total knee arthroplasty and may enhance immediate functional performance on the day of surgery.

Three-Dimensional Evaluation of the Depressor Anguli Oris and Depressor Labii Inferioris for Botulinum Toxin Injections.

BACKGROUND: Botulinum toxin type A (BoNT-A) injection administered at an inappropriate site or depth can produce an unwanted change in facial animation because the depressor anguli oris (DAO) and depressor labii inferioris (DLI) muscles are partially overlapped. Therefore, simple BoNT-A injection guidelines, based on 3-dimensional (3D) facial anatomic references and landmarks, would be very useful. OBJECTIVES: The aim of this study was to establish novel BoNT-A injection guidelines that include the soft tissue thickness at the lower perioral region. Data were acquired with a 3D scanning system combined with dissections in order to obtain accurate injection sites and depths for the DAO and DLI. METHODS: 3D scans of the facial skin, superficial fat, and facial muscle surface were performed in 45 embalmed cadavers. The thicknesses of the skin and subcutaneous layer were calculated automatically from superimposed images at each of 5 reference points (P) in the perioral region. RESULTS: In every case (100%), P3 and P5 were located in the DLI and DAO areas, respectively (45/45). Therefore, we defined P3 as the "DLI point" and P5 as the "DAO point." The soft tissue thicknesses at the DLI and DAO points were 6.4 [1.7] mm and 6.7 [1.8] mm, respectively. CONCLUSIONS: The P3 and P5 described in this study are effective guidelines that only target the DLI and DAO. Clinicians, specifically, can easily use facial landmarks, such as the cheilion and pupil, to assign the DLI and DAO points without any measurement or palpation of the modiolus.

Cadaveric Dissections to Determine Surface Landmarks Locating the Facial Artery for Filler Injections.

BACKGROUND: The facial artery is a high-risk structure when performing filler injections at the nasolabial fold, buccal, and mandibular regions. OBJECTIVES: This study aimed to establish reference landmarks locating the course of the facial artery and its essential branches. METHODS: Thirty-one embalmed cadavers were enrolled in this study. The course of the facial artery was observed in regard to the following reference points: masseter insertion, oral commissure, and common bony landmarks. The corner of the mouth was utilized as the landmark to measure the turning point of the facial artery. RESULTS: Seven points were established to identify the course and turning point of the facial artery. These included the anterior masseteric, lateral mental, infraorbital, medial canthal, basal alar, post-modiolar (PMP), and supra-commissural (SCP) points. The course of the facial artery deviates at least twice at the lateral mental points and at the SCP or PMP. The facial artery appeared more medially when the artery turned at the PMP and SCP. It presented through the lateral channel if the turning point was solely at the PMP. Wherever the facial artery deviates, it can be divided into 3 segments: the mandibular, buccal, and nasolabial segments. The arterial course may deviate laterally from the mouth corner towards PMP. The nasolabial segment may also deviate laterally to the basal alar point at the alar grove for 0.5 to 1 cm. CONCLUSIONS: The deviation of facial artery closely relates with mandibular, buccal, and nasolabial segments. It is essential in avoiding arterial injury for physicians and surgeons who perform procedures in these areas.

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.

Localization and Topography of the Arteries on the Middle Forehead Region for Eluding Complications Following Forehead Augmentation: Conventional Cadaveric Dissection and Ultrasonography Investigation.

Forehead augmentation with filler injection is one of the most dangerous procedures associated with iatrogenic intravascular injection resulting in the severe complications. Nonetheless, few studies have determined the explicit arterial localization and topography related to the facial soft tissues and landmarks. Therefore, this study aimed to determine an arterial distribution and topography on the middle forehead region correlated with facial landmarks to grant an appropriate guideline for enhancing the safety of injection. Nineteen Thai embalmed cadavers were discovered with conventional dissection and 14 Thai healthy volunteers were investigated with ultrasonographic examination on the middle forehead. This study found that at the level of mid-frontal depression point, the transverse distance from the medial canthal vertical line to the superficial and deep branches of supraorbital artery were 9.1 mm and 15.1 mm, respectively. Whereas the depths from the skin of these arteries were 4.1 mm and 4.3 mm, respectively. Furthermore, the frontal branch of superficial temporal artery was detectable in 42.1% as an artery entering the forehead area. At the level of lateral canthal vertical line, the vertical distance of frontal branch was 31.6 mm, and the depth from skin of the artery was 2.7 mm. In conclusion, a proper injection technique could be performed based on an intensive arterial distribution and topography, and ultrasonographic examination before the injection is also suggested in order to restrict the opportunity of severe complications.

The Novel Costotransverse Foramen Block Technique: Distribution Characteristics of Injectate Compared with Erector Spinae Plane Block.

BACKGROUND: The costotransverse foramen (CTF) is a space continuous with the paravertebral space. We hypothesized that injections passing through the CTF will result in a successful injectate spread to the paravertebral space. OBJECTIVES: We investigated patterns of dye spread to assess characteristics of neural blockade following ultrasound-guided CTF and erector spinae plane (ESP) injection in an anatomic and clinical study. STUDY DESIGN: Prospective cadaveric study, and case studies. SETTING: University hospital. METHODS: Six soft cadavers were studied. The boundaries of the CTF and the needle pathway of CTF injection were identified in the first cadaver. The CTF and ESP injections were performed on either the left or right sides of the T4 vertebral level in cadavers 2 to 6. Fifteen milliliters of 0.2% methylene blue was injected in each block, and the spread of dye was assessed by anatomic dissection. We also report 2 case studies of CTF and ESP blocks. RESULTS: Cadaver studies of CTF injection demonstrate that with injection to the inferior aspect of the base of the transverse process, the dye mainly passes anteriorly through the CTF into the paravertebral space, with minimal track-back to the deep back muscles. Consistent sensory blockade was achieved in 2 case studies. With the ESP injection, the spread of dye was observed cephalocaudad to the fascia of the erector spinae muscle, with no dye spreading within the paravertebral space in all cadavers. LIMITATIONS: Prospective case series. CONCLUSIONS: CTF block was consistently associated with a mainly anterior spread of injectate into the paravertebral space that involved the thoracic spinal nerves, and minimal posterior spread of injectate to the deep back muscles. KEY WORDS: Thoracic vertebrae, rib cage, paraspinal muscle, nerve block, joints.

A novel anatomical consideration on the exposed segment of the facial artery.

An understanding of the location and depth of the facial artery (FA) is essential in aesthetic surgery and various cosmetic procedures. The purpose of this study was to clarify the three-dimensional (3D) topography of the exposed segment (ES) of the FA and to provide information to help minimize complications during clinical procedures. From 50 embalmed adult cadavers, the undissected and dissected hemifaces were scanned and reconstructed using the 3D scanner. Then the topographic location of the ES was identified and measured from the superimposed the 3D images. The ES was observed in 82% of the whole specimens. The exposure patterns of the ES were examined, and classified into three types: Type I, one site exposed pattern (74%); Type II, two sites exposed pattern (8%); and Type III, nonexposed pattern (18%). The extent of the ES was located at 2.2 mm above and 4.2 mm below the cheilion (Ch)-otobasion inferius line, and 20.0 to 25.2 mm from the Ch on the lateral aspect. In the frontal view, the average distance from the mid-pupillary line to the ES was 7.1 mm, and from the lateral canthal line to the ES was 6.1 mm. The ES was 7.6 mm below the skin surface. The results of this study will help to provide safe guidelines for filler injections as well as selecting the safe regions in various clinical procedures. Clin. Anat. 33:257-264, 2020. © 2019 Wiley Periodicals, Inc.

Anatomical and ultrasound-based injections for sunken upper eyelid correction.

BACKGROUND: A needle or a cannula can be safely used during filler injection procedures to correct a sunken upper eyelid. To date, there are no precise injection points recommended that are based on an anatomical study. OBJECTIVE: This study systematically investigated the vascular pattern and depth of forehead arteries at the periorbital area of upper eyelid. METHODS: Twenty cadavers were dissected in this study. Additional data were obtained from 30 healthy volunteers using Doppler ultrasound imaging with high-frequency probe. RESULTS: The ophthalmic artery divided into two opposite primary branches: the superior and inferior orbitoglabellar arteries running along the orbital rim. After the supratrochlear artery arose from the superior orbitoglabellar artery at the medial eyebrow, the supraorbital artery either divided from this artery near the supraorbital foramen or emerged as an individual artery from the supraorbital notch. The inferior orbitoglabellar artery gave off the radix artery superior to the medial canthal tendon. The radix artery divided into two opposite branches: the dorsal nasal artery going to the nose and the paracentral artery going to the glabella. Ultrasound imaging revealed a subcorrugator space that a cannula can safely pass through. At the supraorbital foramen/notch, the supraorbital artery traveled very close to the bone. Based on the anatomical data collected, the following injection points for a needle and a cannula technique are recommended. CONCLUSION: Correction of a sunken upper eyelid is a dangerous procedure which should be performed only by experienced physicians. However, with precise anatomical knowledge and correct techniques, optimal outcomes can be safely achieved.

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.

Implication of Location of the Ascending Mental Artery at the Chin Injection Point.

BACKGROUND: Facial proportions can be improved by means of chin augmentation in patients with a receding chin. The ascending mental artery is the main arterial supply to the top of the chin, and arterial occlusion of this artery can result in soft-tissue infarction. This study aims to measure the topographic anatomy of the ascending mental artery at the chin injection area, using a three-dimensional camera. METHODS: Thirty-one embalmed cadaveric faces were dissected at the chin. The midline of the inferior margin of the mandibular protuberance was marked with a pin. A variation in size between the two opposite ascending mental arteries was noticed. The depth of the artery from the skin surface and distance from the midline were measured using a three-dimensional camera. RESULTS: There were 19 dominant ascending mental arteries on the right and 12 on the left. The dominant ascending mental arteries enter the chin paracentrally, approximately 6 mm (mean ± SD, 5.64 ± 4.34 mm) from the midline, within the muscular plane, and at a depth of 4.15 ± 1.95 mm from the skin. Furthermore, the artery formed an anastomosis with the sublingual artery, within the floor of the mouth. CONCLUSION: Every aesthetic physician should recognize the course of the ascending mental artery and use the appropriate techniques to avoid vascular injury during chin augmentation using filler injections.