- Not routinely used, but some patients may request topical anesthesia
- Options include
- Skin cooling with
- Cooling machines
- Topical anesthetic creams
- Mixtures of lidocaine and prilocaine are common.
General injection technique
The skin should be cleaned with alcohol prior to injection.
Needle depth depends on the area being treated and the skin thickness in that area:
- Around the eyelids, which have the thinnest skin in the body, injection should be very superficial.
- Deeper injection is required around the thick skin of the glabellar region.
Once the desired needle depth and location has been achieved, the toxin should be injected slowly to both deliver the precise desired dose and reduce patient discomfort.
Generally speaking, toxin should be directed at the muscle causing the undesirable wrinkle or contour, not directed at the wrinkle itself (Figure 3).
Figure 3. Accentuated dynamic rhytids (on patient's left), including horizontal forehead lines, glabellar furrows, and lateral canthal lines. Facial musculature typically targeted by toxin (on patient's right), including A: Frontalis; B: Corrugator supercilii; C: Procerus; D: Orbicularis oculi; E: Zygomaticus minor; F: Levator labii superioris; G: Levator labii superioris alaeque nasi; H: Orbicularis oris; and I: Depressor angulus oris.
Need to be tailored to the patient (and therefore will require a "start low, go slow" titrating approach), however there are generalized advised injection dosages for the different targeted muscles
The clinician must also be aware of gender differences in dosing, due to a larger muscle volume in males, which generally requires more units of toxin to achieve the same result as females
Indication-specific strategies and sample injection
Dosages mentioned here pertain to BOTOX® and Xeomin®; a 2.5:1 to 3:1 adjustment would need to be made for Dysport®).
Horizontal forehead lines (Figure 4)
Target the frontalis.
- Goal is to weaken but not completely paralyze the brow ("frozen" brow).
- Recommended dosage is 6 to 15 units over 4 to 8 injection sites.
- Certain studies have shown better results with higher doses (24 units) (Carruthers).
Maintain a distance of about 1 to 2 cm above the supraorbital rim to avoid brow ptosis.
Figure 4. (a) Sample injection pattern for the treatment of horizontal forehead lines, targeting the frontalis muscle. (b) 2 weeks after injection, demonstrating frontalis weakening and reduction of horizontal lines.
Vertical glabellar lines (Figure 5)
Deeper injection: Target the superficial procerus and deeper corrugator supercilii.
- Some clinicians elect to start low with starting dosages of 10 to 30 units for women and 20 to 40 units for men.
- Others believe this area requires a higher treatment dose, using dosages of 20 to 40 units for women and 40 to 80 units for men.
Usually 5 sites are injected.
Care should be taken to avoid injecting below the supraorbital rim because this could lead to toxin migration inferiorly to affect the levator, leading to blepharoptosis.
Figure 5. Sample injection pattern for the treatment of vertical glabellar lines, targeting the procerus and corrugator supercilii.
Lateral canthal lines (crow's feet) (Figure 6)
Target the orbital portion of the orbicularis oculi; superficial injection
Typical dosage: 10 to 30 units for women and 20 to 30 units for men over 2 to 5 injection sites
Maintain a distance of 1 to 1.5 cm lateral to the lateral orbital rim to minimize weakening of the palpebral portion of the orbicularis oculi, which may lead to lagophthalmos or dry eye.
Medial migration may also affect the levator, resulting in eyelid ptosis.
Avoid injecting below the level of the zygoma to avoid weakening of the zygomaticus major, which may result in mouth droop.
Figure 6. Sample injection pattern for the treatment of lateral canthal lines (crow's feet), targeting the orbicularis oculi.
Lines on dorsolateral nose (bunny lines)
Target the nasalis.
- A single injection of 2 to 4 units on each side of the nasal dorsum about 1 cm superior to the alar groove
- Occasionally, a midline injection is also performed.
More inferior injection may affect the levator labii superioris or alaeque nasi, leading to lip droop.
Vertical perioral lines (Figure 7)
Target the orbicularis oris.
- Because this area is prone to significant functional issues — drooling, difficulty eating/drinking — treatment should be very conservative
- Start with a very low dose of 0.5 to 1 unit, then titrate.
At or within 5 mm of the vermilion border, 4 injection points are recommended in the upper lip and 2 in the lower (Semchyshyn).
Avoid treating patients who use their orbicularis oris to play musical instruments or sing.
Because of the nature of the wrinkles and the inability to use large doses, this area may be best treated with adjunct modalities such as soft tissue fillers.
Figure 7. Sample injection pattern for the treatment of vertical perioral lines, targeting the orbicularis oris at (or within 5 mm of) the vermilion border.
Melomental folds (marionette lines) (Figure 8)
Target the depressor anguli oris.
Typical dosage: 3 to 5 units injected at the mandible level at the posterior portion of the depressor anguli oris and at the anterior edge of the masseter
Injections that are either too anterior or too high may weaken the depressor labii inferioris muscle, leading to oral incontinence issues similar to those discussed above in the treatment of vertical perioral lines.
Figure 8. Sample injection pattern for the treatment of melomental folds (marionette lines), targeting the depressor anguli oris.
Brow elevation is achieved by treating the glabellar area (see above) as well as the superolateral orbicularis oculi (approximately 5 units; gives additional elevation to the tail of the brow), both of which contribute to brow depression.
In these patients, it is beneficial to avoid treating horizontal forehead rhytids with frontalis injections to maximize brow height.
Target the hyperfunctioning upper lip elevating muscles: levator labii superioris alaeque nasi, levator labii superioris, zygomaticus minor.
Typical dose: 2 to 5 units per side, 2 injections per side, directed into overlapping points of the levator labii superioris alaeque nasi and levator labii superioris and overlapping points of the levator labii superioris and zygomaticus minor,
Target the mentalis muscle at the prominence of the chin.
Typical dosage: 5 to 10 units via 1 to 2 injection sites
Horizontal chin crease
Target the mentalis muscle.
Typical dosage: 3 to 5 units on each side of the midline
Avoid injection directly into the crease because this may cause oral incompetence.
Platysmal bands (Figure 9)
Target each platysmal band.
Typical dosage: 15 units per platysmal band, 3-4 injection sites per band, separated by 1 to 1.5 cm (Brandt)
Do not exceed 30 to 40 units of toxin per treatment to avoid the rare complications neck weakness or dysphagia (Carruthers).
Figure 9. Sample injection pattern for the treatment of platysmal bands, targeting each individual band with 3-4 injections, separated by 1 to 1.5 cm.
Botulinum toxin plus filler
Certain cosmetic indications can best be addressed nonsurgically with a synergistic combination of botulinum toxin injections along with soft tissue fillers (e.g., perioral lines, melomental folds, chin dimpling).
This strategy is most effective when there is some component of static rhytids, due to soft tissue changes or devolumization (as opposed to strictly dynamic rhytids).