Temple

The tissue layers in the temporal region are as follows: skin, subcutaneous fat, superficial temporal fascia, deep temporal fascia, and temporal muscle. When injecting in the temple, there are two main anatomical structures physicians want to avoid: the superficial temporal artery and the frontal branch of the facial nerve. Both of these structures are closely associated with the superficial temporal fascia. The superficial temporal fascia is loosely adherent to the subdermal fat and is a continuation of the galea aponeurotica system of the scalp and the superficial musculoaponeurotic system of the face.

The superficial temporal artery is a terminal branch of the external carotid artery. It originates in the parotid gland and crosses the zygomatic arch about 10 millimeters anterior to the tragus. The superficial temporal artery gives off numerous terminal branches, including the transverse facial, the middle temporal, the parietal, and the frontal artery. It is possible to palpate the pulse from this artery in the temporal region.

The frontal branch of the facial nerve supplies motor innervation to the muscles of facial expression of the eyebrows and forehead. It is found along the deep surface of the superficial temporal fascia and is considered to be a nerve at risk when performing procedures at the temple. The most common method of finding this ‘danger zone’ is to draw a line from the ear lobe to the lateral eyebrow and then from the tragus to the superior most forehead rhytid. The result will be a zone that corresponds to the usual trajectory path of the frontal branch. Transection with a needle can result in brow ptosis.

When injecting the temples it is important to stay superficial to the superficial temporal fascia and to avoid these vital structures in the subcutaneous fat. Rather than using a fanning technique to deposit product, as is often deployed in treatment of the cheeks, nasolabial folds, and other areas of the mid- and lower face, the physician should instead deposit product in a depot and distribute it to the temporal region via massage.

Forehead

Though the forehead appears to be a convex structure, there is a concavity that becomes more prominent with age in the suprabrow region. It is located between the frontal eminence of the forehead and the supraciliary arches. Injury to the supraorbital nerve is of concern when treating this area. The nerve exits the supraorbital notch, which lies along the orbital rim medially and is readily palpated. A compression injury to the nerve can be avoided by injecting laterally and at least 1 centimeter from the supraorbital foramen. The preferred injection plane is posterior to the frontalis muscle. The subcutaneous prefrontalis muscle level has been used for PLLA injections. More cohesive fillers like CaHA may not spread as easily and may require multiple injections, thus causing more tissue trauma.

Adjacent to the supraorbital nerve is the supraorbital artery. Retrograde injection can decrease the risk of vascular embolization, as can the use of blunt-tipped cannulas.

Materials

CaHA is a filler with relatively high viscosity. Alterations in the viscosity can be implemented without compromising long-term efficacy. Consequently, prior to administration of CaHA into the forehead and temples, the product should be homogeneously mixed with lidocaine. In our clinical practice, the 1.5 mL syringe of CaHA is combined with 0.5 mL of 1% lidocaine for injections in the temple and with 1.0 mL of 1% lidocaine^® / normal saline diluent mixture for the forehead. This mixing enhances the ease of massaging product throughout the treated area. An ordinary 3.0 mL syringe containing the diluent can be connected to the 1.5 mL syringe, using a female-to-female Luer lock adapter (Fig. 13.1). Existing research by Busso has shown that 10 passes of the CaHA and the diluent back and forth from syringe to syringe is sufficient for homogeneous distribution of both diluent and dermal filler.

Figure 13.1 A Luer lock connector is used to mix the 1.5 mL CaHA syringe with the 3.0 mL syringe containing either lidocaine or lidocaine / normal saline diluent.

Courtesy of Merz Aesthetics, San Mateo, CA.

Injection site for the forehead

The target in the suprabrow area is the suprabrow concavity. Specifically, this area extends inferiorly to the frontal bone supraciliary ridge and superiorly to the frontal eminence, approximately 3 cm away from the supraciliary arches. Laterally, the space to be injected is marked by extension into the temporal compartment below the temporal cheek fat (Fig. 13.2). The floor of the target injection area is the frontal supraperiosteum and the ceiling is the frontalis muscle.

Figure 13.2 The suprabrow concavity extends inferiorly to the frontal bone supraciliary ridge and superiorly to the frontal eminence.

When addressing the medial aspects of the area, injections should extend lateral to the projection of the supraorbital nerve. This projection is located >1 cm from the supraorbital notch or foramen. Injections should be executed at the subcutaneous level, with dermal filler placed at the supraperiosteal level behind the galeal fat pad (Fig. 13.3).

Figure 13.3 Injections should be executed at the subcutaneous level, with dermal filler placed at the supraperiosteal level behind the galeal fat pad.

Reproduced from Busso M 2010 Forehead contouring with calcium hydroxylapatite. Dermatologic Surgery 36(S3):1910-1913

Injection technique for forehead recontouring

A 27-gauge, -inch (35 mm) needle is used to introduce the CaHA–lidocaine solution into the forehead. A threading bolus is used to place the product in the inferior frontal eminence (Fig. 13.4). The amount of product varies with each patient but the stated objective is reconstitution of the suprabrow arch. When sufficient product has been deposited using retrograde injection for introduction of the bolus, the area is then massaged so that the product is evenly distributed throughout the borders described in the section above. Volumes may range from 1.5 mL to 3.0 mL of CaHA, in addition to the volumes of diluent necessary for mixing.

Figure 13.4 A threading bolus is used to place calcium hydroxylapatite in the inferior frontal eminence.

Reproduced from Busso M 2010 Forehead contouring with calcium hydroxylapatite. Dermatologic Surgery 36(S3):1910-1913

In some cases, a brow lift has also been a fortunate consequence of forehead recontouring. This has occurred without any placement of product directly behind the brow. Even in the absence of a brow lift, however, the filler placement of the patients in a ‘horseshoe’ pattern has resulted in cosmetic benefits, including projection of the lateral eyebrow and reduction of transitions between the suprabrow, temporal, and cheek regions.

Note: After injection, the treated area will likely become edematous. This condition is self-limiting and will resolve in as little as 24 hours in some cases but as long as 10 days in others. An initial temporary brow droop, as opposed to brow lift, is the likely consequence of the diffusion of the lidocaine in the injected solution. The droop is quite short lived, resolving within several hours.

Injection site for the temples

In addressing mid-face contouring, lateral injection in the temples is the starting point. The objective of temple correction is to reduce redundant skin from the periorbital area and, in so doing, re-establish soft tissue arches. The needle is introduced through the skin just above the zygomatic rim, moving deeper between fascia and subcutaneous tissue, avoiding the vascular structures. Tenting the skin to be injected can improve precision of product placement in this site.

Injection technique for temple recontouring

As is the case with the forehead, a 27-gauge, -inch (35 mm) needle can be used to deposit boluses of CaHA plus lidocaine. Depending on the severity of correction, volumes may range from 0.7 mL to as much as 3.0+ mL of CaHA per site. Injections are performed in a retrograde fashion as the needle is withdrawn, to limit inadvertent intravascular injection. After injection, the temples should be massaged vigorously to blend the product into the treated areas, but patients are not required to perform any massage procedures at home.

Note: Temporal ptosis can occur with this treatment, which is likely the result of anesthetic influencing the temporal facial motor nerve. However, as with post-injection forehead edema, this event is short lived and will self-resolve within several days.

Figures 13.5 and 13.6 are representative results of forehead and temple contouring. In Figure 13.5, a 45-year-old female received 3.0 mL of CaHA mixed with 2.0 mL of 1% lidocaine / normal saline diluent. In Figure 13.6, a 40-year-old female received 1.5 mL of CaHA mixed with 1 mL of 1% lidocaine for her forehead and 3.0 mL of CaHA blended with 1.0 mL of 1% lidocaine in her bilateral temple region.

Figure 13.5 Forehead recontouring in a 45-year-old woman after receiving 3.0 mL of calcium hydroxylapatite mixed with 2.0 mL of saline solution / 1% plain lidocaine in temporal and suprabrow areas: (A, C) before, (B, D) after; (A, B), at repose and (C, D) after brow elevation.

Figure 13.6 Forehead and temple recontouring in a 40-year-old woman after receiving 1.5 mL of CaHA mixed with 1.0 mL of 1% plain lidocaine in her forehead and 3.0 mL of CaHA blended with 1.0 mL of 1% lidocaine in her bilateral temple region: (A) before, and (B) afterwards.