To update some new perspectives of cosmetic dermatologic plastic surgeons on the cosmetic procedures of Botulinum toxin head and neck injections and to provide some guidelines for the safe and effective use of Botulinum toxin. The article will review several aspects of indications, recommended doses and dilutions, recommended preservation methods, and injection techniques. Anatomy and patient selection Firstly the practitioner performing the injection must be familiar with the anatomy of the face and secondly the practitioner performing the procedure must be aware of the compensatory mechanisms secondary to the injection of a particular muscle or group of muscles. Selection of the right patient is a prerequisite for successful injection treatment. Patients should be reminded that botulinum toxin injections can only modify power wrinkles and that deep wrinkles formed due to light damage or ageing cannot be well improved. Absolute contraindications to botulinum toxin injections include: those with infections at the injection site, allergies or hypersensitivity to the product. Relative contraindications include: patients with high psychological expectations; patients who depend on the face for their livelihood (actors); patients with neuromuscular diseases such as myasthenia gravis, Eaton-Lambert syndrome; patients who are taking drugs that interact with this product, such as: aminoglycoside antibiotics, penicillamine, quinine and calcium antagonists; pregnant and lactating women. Only a few cases of botulinum toxin injection before pregnancy or during early and late pregnancy have been reported, and no adverse effects have been observed. Only one case of miscarriage occurred after injection in a woman with a history of spontaneous abortion. Botulinum toxin injections can interfere with the monitoring of neuromuscular blockade after general anesthesia because neuromuscular blockade is usually achieved by monitoring the facial nerve that innervates the orbicularis oculi. Therefore, patients need to inform their anesthesiologist if they have had Botox injections within a month prior to general anesthesia, and this group of patients can be replaced by monitoring the peripheral ulnar nerve that controls the thumb muscles. Dilution techniques Botulinum toxin is unstable in nature and care must be taken during dilution. Early literature advocated that sodium chloride be added slowly during dilution to avoid foam formation and that shaking be avoided. We believe that the foaming process and foam can lead to surface denaturation of botulinum toxin. Others have argued that shaking and foaming during dilution with preservative-free saline does not affect the activity of botulinum toxin. This conclusion is consistent with our clinical experience, but further studies are needed to confirm this conclusion. In conclusion, for now, a slow and gentle dilution process is optimal. Storage The manufacturer recommends that botulinum toxin be used as soon as it has been diluted and dissolved, or in a refrigerator at 2-8°C for 4 hours. A recent study showed that botulinum toxin diluted with sodium chloride containing a preservative was not contaminated by microorganisms when stored in a conventional refrigerator and used by multiple aspirations by multiple physicians. Hexsel et al. found that botulinum toxin diluted in preservative-free saline could be used for 6 weeks and remained active. However, they did not measure the microbial content. The physician performing the injections must be aware that the risk of bacterial contamination in the solution increases with time of use when botulinum toxin is diluted with normal saline without preservatives. In addition, the author has observed that freshly diluted dissolved botulinum toxin is more active, but no controlled studies have been performed. Injection Technique/Dosage In general, the injection procedure should be done vertically and into the muscle. And the injection should follow an individualized protocol. A slight facial asymmetry may occur in most patients, so it is important to explain this to the patient and always take pictures before treatment. The injection site, the quality and strength of the injected muscle, etc. together determine the injection dose and the injection unit (injection site). In general, the number of injection units (points) for men is more than that for women. In order to avoid drooping of the eyelid due to diffusion of botulinum toxin to the levator muscle, the injection site should be at least 1 cm higher than the upper frame edge, and pressing the finger next to the injection site can reduce pain and bruising. The eyebrows should not be used as a marker for injection because the eyebrows themselves have problems such as drooping and uneven thickness, and operations such as eyebrow trimming and tattooing can change the original shape of the eyebrows. After treatment some patients compensate for the paralysis of the frown muscle by strengthening the contraction of the transverse fibers of the orbicularis oculi, leading to the following consequences: 1. increased vertical wrinkles; 2. upper lids pulled closer to the middle. These patients can be improved by a small injection of botulinum toxin into the orbicularis muscle above the orbital rim. Carruthers compared the effectiveness, safety, and duration of treatment effects of 10, 20, 30, and 40 U of botulinum toxin in the treatment of interfrown lines in women. In general, 20-40 U Botox was more effective than 10 U Botox and had the longest duration of treatment. There was no difference between 20, 30 and 40 U Botox. Most patients have a treatment duration of 3-4 months; some patients can last up to 12 months. 96% of female patients start treatment with 20 or 30 U of Botox. Forehead Lines 1. Injection Technique Before performing forehead muscle injections, patients, especially older patients, should be evaluated for sagging eyebrows and eyelids. Patients with drooping eyebrows and eyelids will correct and compensate for this drooping state by contracting the frontalis muscle. This group of patients is not suitable for frontalis injections, as any weakening of their frontalis contraction may result in visual field loss. In general frontalis injections alone without interbrow injections should be avoided. When performing frontal injections, it is important to keep in mind that the injection site is at least 1 cm above the superior orbital rim to reduce the occurrence of brow ptosis. It is now common practice to perform injections greater than 2 cm from the superior orbital rim to maintain partial motor function of the brow and to avoid the development of a frozen face. The injection pattern varies depending on the patient’s desired brow shape. Female patients generally prefer an arched brow shape, while male patients want a flat brow shape. For female patients seeking an arched brow, the injection point should be concentrated in the center of the frontalis muscle, but this can result in a residual wrinkle above the lateral brow and even a “Jack Nicholson” look. The countermeasure is to inject 1-2U of Botox 2cm above the brow crest. In male patients, all frontalis muscles including the lateral portion need to be injected. A study comparing the efficacy of 20, 40, 60 and 80 U of botulinum toxin for the treatment of frown lines in male patients found that 20 U was less effective than the other doses. 38% of male patients would start with 40 U of botulinum toxin and 30% would start with a higher dose of 45-120 U. Levy et al. reported that the effect of 5 or 10 U botulinum toxin for power wrinkles on the forehead was the same. And the dose has no effect on the maintenance time of the effect. The authors emphasized that low-dose botulinum toxin injections could achieve better clinical results without forming a frozen face. However, the study did not disclose whether the subjects were male or female. Carruthers et al. compared the effects of three different doses of botulinum toxin, 16, 32 and 48 U, for the treatment of horizontal forehead lines. The study found that higher doses of botulinum toxin were more effective and lasted longer. Ninety-four percent of the panel recommended an initial dose of 10-20 U for female patients and 61% recommended a lower initial dose. 32% of the experts recommended an initial dose of 20 U for male patients and 46% recommended an initial dose of 30 U. So the typical initial dose is 15 U for female patients and 20 U for male patients. Brow lift 1. Injection techniques There are two techniques to achieve a brow lift: (1) interbrow spot injection alone; (2) lateral orbicularis oculi injection perpendicular to the muscle fibers; some people perform lateral orbicularis oculi injections at only one site on the temporal fusion line. Two theories can explain the principle of action of interbrow spot injections: first, attenuating the action of the descending brow muscle. Secondly, the diffusion of botulinum toxin can inactivate some intermediate fibers of the frontalis muscle, resulting in increased muscle tension in the lateral and upper frontalis muscle fibers. 2.Injection dose Research shows that only 20-40U botulinum toxin injected in the interbrow point can get a good effect of raising the eyebrows, and the best effect is 12 weeks after treatment. Ahn et al. demonstrated that 7-10U Botox injected into the lateral orbicularis oculi muscle from the lateral to the middle pupil line could significantly raise the eyebrows. Crow’s feet 1. Injection technique Crow’s feet are treated by injecting into the orbicularis oculi muscle at the lateral edge of the orbit. Attention should be paid to the superficial depth of injection and keeping the injection point at a distance of 1-1.5 cm from the lateral orbital edge to avoid affecting the part of the orbicularis oculi muscle that governs the eyelid and the muscle that governs eye movement and causing adverse reactions such as strabismus or eyelid ptosis. The injection site below the zygomatic arch should be avoided to avoid peripheral facial palsy-like manifestations: cheek and lip angle ptosis. Care should be taken to identify wrinkles caused by the orbicularis oculi and zygomaticus muscles. Wrinkles caused by zygomatic muscle contraction can only be improved by zygomatic muscle toxin injections, but the injection can cause sagging on one side of the face and asymmetry between the left and right side of the face when smiling. These two types of crow’s feet can be identified: tell the patient to close the eyes tightly, the crow’s feet produced at this time are caused by the orbicularis oculi muscle and can be improved by botulinum toxin injection. 2. Injection dose The Lowe et al. study found that Botox injections of 6, 12, and 18 U per side of the crow’s feet resulted in significant improvement (both male and female patients were included in the study). The study did not find a clear dose-response relationship. Another study found that larger doses of botulinum toxin were more effective and lasted longer (3, 6, 12, and 18 U per side.) There was no significant difference between 12 U and 18 U, and the authors concluded that 12 U per side was the optimal treatment dose. The common conclusion reached by the panel: for women, the initial treatment dose was 8-16 U per side for 96% of crows feet, while for men it was 12-16 U per side. Infraorbital crease 1. Injection technique Lower eyelid injections can improve lower lid wrinkles and open your eyes. This part of the patient should be strictly selected before performing injections. Patients with lower lid laxity and those treated with previous eyelid surgery are more likely to have ectropion-like complications. Patients with eyelid fat accumulation are also not suitable, as the fat will be more pronounced with weakened muscle groups. Other contraindications include: Sjogren’s syndrome, other conditions with dry eye symptoms, etc. Injections are made directly into the anterior portion of the orbicularis oculi muscle lid plate, and the needle should be angled to avoid puncturing the orbital cavity. Usually one or two sites are injected, with the first one positioned 3 mm below the lid margin on the pupillary midline and the other at the midpoint between the pupillary midline and the outer canthus. The depth of the injection should be superficial so as not to penetrate the inferior oblique muscle of the eye (which can cause diplopia). 2. Injection dose Some studies have reported that 2U botulinum toxin injections in the lower eyelid can mildly improve symptoms. Patients treated with lower eyelid injections in this study in combination with fissure injections achieved better results. In another study, a dose-response curve study with 2, 4, and 8 U of botulinum toxin found that treatment efficacy increased with increasing dose, but with a corresponding increase in side effects. patients in the 8 U injection dose group were dissatisfied with treatment due to adverse effects such as photophobia, lower lid edema, and lid sphincter insufficiency. In addition excessive lid fissures and excessive fullness of the lower lid were also unsatisfactory in this group of patients. Therefore the investigators recommend 2 U as the initial dose for lower lid treatment, either alone or in combination with fissure injections. patients are followed up at 2 weeks and if there are no unsatisfactory side effects and some improvement in the lower eyelid, another 2 U injection can be performed. Nasal wrinkles 1. Injection technique The point of entry is above the lateral nasal facial groove of the nasal wall. Pressing should be avoided when injecting, especially when injecting downward to avoid infiltration of botulinum toxin into the upper lip muscle of the nasal lift leading to ipsilateral lip sagging. 2.Injection dose The expert group agreed that the initial dose is 2-5U, and male patients can adjust the dose upward by 1U. Perioral wrinkles 1. Injection technique The injection point is the upper lip vertical fold on both sides along the top of the lip margin, superficial injection should be avoided in the corners of the mouth to avoid lateral lip droop and salivation. Common side effects of injections in this area are inability to perform whistling movements, difficulty in pronouncing “p” and “b”, difficulty in kissing, difficulty in eating a liquid diet, difficulty in drinking through a straw, etc. Musicians and people in the broadcasting industry should not be treated in this area. Patients with very thin upper lip or severe atrophy should not receive injection treatment in this area. 2.Injection dose The purpose of injection treatment is to achieve maximum effect with minimum dose and to maintain the normal physiological function of the mouth. The average initial dose of perioral injections is about 5-6 U. Most experts recommend 1-2 U for each injection site. The literature reports that perioral wrinkles have a shorter retention time than forehead lines and frown lines, and patients need a new treatment every 2-3 months. Raising the corners of the mouth 1. Injection technique Patients should determine the position of the descending corners of the mouth muscle by pulling down the corners of the mouth to expose the lower teeth as an action prior to injection. The injection site is positioned at the point where the nasolabial fold extends laterally downward to intersect with the chin (Figure 9). It is important to determine the muscle to be injected before the injection. If the injection site is too close to the medial side, it can lead to a weakening of the role of the ipsilateral descending labial muscle and thus a weakening of the sphincter of the orbicularis oris muscle. 2.Injection dose The lower dose is usually used: 2-5U per side. Chin Dimple 1.Injection Technique As the chin area is rich in fat, the depth of injection should be deeper. Single point or two point injection method in the median line. The injection site is the end of the chin muscle furthest from the orbicularis oris muscle – that is, the chin augmentation. This site is chosen to avoid weakening the role of the orbicularis oris muscle. Most experts agree that experienced users should start with 5-6 U and slowly increase to 12 U. In general, 5-10 U is sufficient. If there is more than one injection site, the total dose is divided equally among each injection site. Raising the tip of the nose 1. Injection technique Injection site. Extra care must be taken for people with a wide distance from the nasal column to the lips, because the injection may cause the upper lip to sag. 2.Injection dosage The total amount of injection in this area is routinely 2-3 U. Gummy smile 1.Injection technique Injections are made from the folds of the nose and face to the upper lip lift muscle, and the injection point can be determined by placing the fingertip in the pear-shaped hole immediately adjacent to the nasomandibular groove. 2. Injection dose 1U per injection site. Broad muscle band 1. Injection technique The position of the broad muscle band is determined by clenching the patient’s teeth and strongly contracting the neck. Inject at intervals of 1.0 to 1.5 cm, starting from the lower jaw and proceeding down the band to the border of the clavicle. Side effects include: weakened contraction of the neck muscles, difficulty in occurrence and difficulty in swallowing. 2. Injection dose The amount of injection dose at this site is reported to be highly variable in the literature. Some scholars agree that a total of 50-100 U of botulinum toxin is required per patient to achieve significant improvement. However, Kane uses a dose of 10-40 U. Another group consensus recommends an effective total dose of 6-40+ per stripe. Jawline Reshaping/Micro Neck Lift 1. Injection Technique This is the method the author has used for micro reshaping of neck laxity and jawline. The injection sites are 6 points evenly distributed along the jawline. 2.Injection dose The dose for the four lateral frontal injection sites was 3-4U, and the dose for the middle injection site was 2U.