Structural fillers of the face

Hyaluronic acids

Hyaluronic acid (HA) products (e.g., Restylane, Juvederm, Perlane, Voluma, etc.) are the most broadly used fillers. Their popularity stems from the fact that they are easy to use, predictable, safe, supportive of soft tissue, minimally immunogenic, and reversible. Because HA fillers are reversible and are associated with a lower incidence of embolic phenomena, it is our preference to use these for structural filling in the face. The elastic modulus (G’) and viscosity of HA can be varied, and the introduction of stiffer, more supportive HA products (e.g., Restylane, Perlane, Juvederm Plus, Voluma) has led to the evolution of their use from wrinkle correction to facial contouring. Restylane and Perlane have the highest G’ and viscosity and Juvederm Plus, Ultra Plus, and Voluma have intermediate G’. These fillers are placed subcutaneously or preperiosteally to provide structural support of soft tissues. The ability to change the shapes of facial features with a nonsurgical approach provides the surgeon with a powerful tool in aesthetic maxillofacial surgery.

Radiesse

Radiesse is composed of a suspension of 30% calcium hydroxylapatite microspheres (25–45 μm) in a 70% gel consisting of 1.3% sodium carboxymethyl cellulose, 6.4% glycerin, and 36.6% sterile water for injection. Radiesse stimulates no foreign body reaction and is immunologically inert. The effects of Radiesse have been reported to last from 2 to 7 years, ^, although clinical effects may disappear as early as 6 to 9 months.

Sculptra

Sculptra consists of a powder of poly-L-lactic acid microspheres (1–63 μm in diameter), sodium carboxymethylcellulose, nonpyrogenic mannitol, and sterile water for injection. Long-term tissue filling effects are caused by ingrowth of type I collagen into the areas of accumulated particles as the polylactic acid microspheres undergo dissolution, which takes place weeks to months after injection. Sculptra requires preparation by hydrating the product at least 2 hours before the injection. The best results require a series of injections spaced 2 weeks apart. After the initial injection, the water that Sculptra is mixed with will be resorbed, but the patient must be informed that collagen stimulation will take several months to produce the optimal result.

Vascular anatomy

Vascular impairment is an infrequent, but dreaded, complication of facial filler injections. An understanding of the vascular anatomy and physiology is essential when injecting in the facial region ( Fig. 36.1 ). The face is perfused with vessels form both the internal carotid artery and the external carotid artery. The ophthalmic artery arises from the internal carotid artery and leads to the dorsal nasal, supraorbital, and supratrochlear arteries. The facial artery arises from the external carotid artery and gives rise to the facial artery, which is the source of the labial, angular, and lateral nasal arteries. Direct anastomoses between the anterior facial vessels enable emboli to traverse between the internal and external carotid systems. It is these anastomoses that have led to emboli that cause blindness.

Ashton et al. studied the functional angiosomes of the face and their association with tissue necrosis. It has been reported that injection-mediated tissue necrosis frequently occurs at a site remote from the injection site, and Ashton et al. found that all complications, regardless of injection site, occur in only five facial regions. Choke vessels have the ability to control or “choke” the flow between angiosomes. Studies have shown that intravascular HA is highly inflammatory and thus can induce choke vessel spasm and reduce perfusion leading to necrosis. Alternatively, if adjacent angiosomes are connected by an anastomosis rather than a choke vessel, the HA can continue through the anastomoses until it hits a choke vessel in a distant angiosome causing remote necrosis. The choke vessel physiology has implications in the application of nitroglycerin paste after suspected filler-induced ischemia. If nitroglycerin paste causes vasodilation opening the choke vessels that are containing the HA, the HA can proceed to distant angiosomes exacerbating the extent of tissue loss. This theory is corroborated by some case reports of worsening necrosis after application of nitroglycerin paste.

History

The application of dermal fillers for facial reshaping differs from that for simple wrinkle and fold correction. Patients who present for facial reshaping may desire correction of asymmetry, change in facial shape, isolated alteration of specific anatomic features (e.g., nose, chin), or gender-related changes. It is important to obtain a detailed history of desires, expectations, and limitations of the result. For instance, chin augmentation with fillers has limitations because the chin pad has an amorphous shape and texture and does not exhibit the strong skeletal nature of a normal chin; similar limitations exist for filler rhinoplasty. A previous history of surgery or radiation is also important. In these patients, autologous fat grafting may be a better option, given the potential for stem cell regeneration. Finally, medications and medical conditions (e.g., bleeding disorders) should be noted and the associated risks should be discussed.

Physical examination

Facial reshaping with dermal fillers focuses on certain regional areas where the illusion of skeletal change can be created through the use of fillers.

• Temporal region: The patient is examined to assess the degree of temporal hollowing and to also note any asymmetry.

• Forehead: The forehead should exhibit a smooth, symmetrical, and slightly convex contour.

• Glabella: The glabella should have a convex shape in the profile view. This contributes to the aesthetic quality of facial divergence, as discussed in Chapter 16 .

• Nose: The nose should be evaluated as described in Chapters 28 and 29 . Specific anomalies amenable to placement of fillers are low dorsum, low radix, decreased tip projection, and asymmetry.

• Midface region: The cheeks should be assessed for projection and symmetry. Bizygomatic width is also noted; this dimension has a profound influence on the perception of facial shape. Asian patients typically exhibit wide bizygomatic width and less projection in the medial malar region. Placing fillers in this region can create the illusion of a narrower face. In contrast, Western women desire augmentation of the lateral zygoma to restore cheek fullness. The effects of structural fillers in both sets of patients create the ideal oval face.

• Mandible: The entire mandible is assessed for symmetry, width, and contour. Analyses of the mandible and the chin should be performed separately because each influences the perceived shape and position of the other. Masseter muscle bulk is assessed in addition to the bone dimensions of the gonial region.

• Chin: The symmetry, projection, and shape of the chin are noted. The acuity of the labiomental crease and the soft tissue support of the underlying mentalis are also noted.