Introduction

The cheeks are facial cosmetic units that easily reveal one’s age, owing to their progressive volumetric reduction after the third decade of life. They play a fundamental role in facial expression, transmitting happiness through smiles and laughs.

Each cheek is composed by the soft tissues covering the paramedian central facial skeleton (Table 18.1). The upper third of the cheek can be further divided into zygomatic and infraorbital subunits. The zygomatic subunit (cheekbone) represents the area of maximal projection of the cheek, called the malar eminence (Fig. 18.1A). The ideal malar eminence diffusely reflects light regardless of the angle one looks at the face. The cheeks work as a frame for adjacent cosmetic units such as the lips, eyes, and ears, allowing the observer to instinctively calculate cosmetic ratios related to those structures.

Table 18.1 Borders of the cheek

Figure 18.1 Important cosmetic features of the cheek: (A) anatomical limits and subunits (IO = infraorbital, Z = zygomatic, SMT = submalar triangle, TT = tear trough, PSP = parasagittal profile contour); (B) location of the malar eminence by the Hinderer method.

Modified from Naini FB 2011.

Although prominent cheekbones are usually associated with beautiful individuals, it is their relationship with the other facial structures that defines attractiveness. Several techniques are available to identify the optimal location of the malar eminence. Hinderer’s method is easy to obtain, helping to optimize filler placement when augmenting the cheeks. The ideal reflection of light should be kept in the upper outer quadrant formed by the intersection of two virtual lines: the first one runs from the lateral canthus of the eye to the angle of the mouth; the second one goes from the nasal crease to the tragus. Other aesthetic features of the cheeks are superficial textural homogeneity, lack of shadows, and smooth transition towards adjacent cosmetic units. Accordingly, the ideal parasagittal profile contour should have a smooth curvilinear shape from the eyelids to the cervical jaw angle (Fig. 18.1B).

Aging of the mid-face is essentially caused by atrophy of the cheek bones and fat pads. In two areas these changes are striking: (1) within the submalar triangle (an inverted triangle defined medially by the nasolabial fold, superiorly by the malar eminence, and laterally by the anterior border of the masseter muscle) and (2) along the tear trough and eyelid / cheek junction. These changes lead to a deflated balloon pattern – folding the overlying skin. In addition, mid-face atrophy loosens the tissue surrounding the angle of the mouth, leading to a sad appearance (Fig. 18.2A). Filling the cheeks helps in restoring a gracious oral commissure (Fig. 18.2B).

Figure 18.2 Artistic illustration of oral commissure groove improvement by mobilizing tissue around the angle of the mouth when performing augmentation of deep planes in the upper cheek: (A) before, and (B) after filler placement.

The young face can be depicted as a descending triangle with the lower vertex on the chin and the lateral ones on the malar eminence. Mid-facial atrophy accentuates the jowls, inverting that triangle by placing its vertex on the glabella. A traditional surgical lift can partially reverse those changes; however, it may not provide a youthful look since it does not adequately reconstitute volumetric loss. Solid implants successfully augment the cheek bones, but are not suited to reconstitute volume in the submalar units. Filling the cheeks can be combined with lifting techniques to produce more natural results. Augmentation per se provides significant rejuvenation for many patients. The added volume effaces undesirable shadows, restores luminosity to the malar eminence, improves marionette folds, and reduces jowls.

Autologous fat transfer offers excellent overall cheek augmentation (Fig. 18.3). However, it requires harvesting of tissue, which may be difficult to obtain in the presence of generalized fat loss, as seen in some patients with drug-related HIV lipoatrophy. The duration of fat grafts is variable according to the technique used and recipient area (the cheeks usually have good retention rates); it also varies among individuals. Coleman reported that injecting small droplets of donor tissue, so that the whole graft receives enough nutrients, improves graft survival. Sterodimas et al found that adipose-derived stem cell-enriched lipografts may also prolong results. Despite those advances, liposculpture may not be attractive to individuals looking for office-based procedures.

Figure 18.3 Fat-transfer augmentation of the mid-face anterior temples (total bilateral volume = 25 mL) associated with submandibular liposuction: (A) before, and (B) after 8 months.

Fat augmentation techniques have been adapted for exogenous materials. Non-resorbable fillers may offer excellent long-term results but also impose permanent risks of foreign-body reactions and migration. Silicone, polymethylmethacrylate suspensions, and polyacrylamide gel are permanent fillers approved in many countries. Over the past decade, poly-l-lactic acid (PLLA) and hydroxylapatite became popular and transformed cheek augmentation in a low-risk office-based procedure, as reported in the studies by Burgess and by Tzikas respectively. Recent improvement in the cost-effectiveness of high-density monophasic and large-particle biphasic hyaluronic acids (HAs) continues to revolutionize the field (see Carruthers et al and Grover).

This chapter and attached video focus on using HA for mid-face augmentation. PLLA and hydroxylapatite are briefly discussed.

Anatomical and technical considerations when filling the cheeks

Minimal deviations from the ideal aesthetic canons described above do not threaten a beautiful face; rather they make each of us unique. Nevertheless, following standard cosmetic principles facilitates the assessment of areas benefiting from augmentation, and how much volume should be used. Understanding facial anatomy and product idiosyncrasies is a must! Exercising one’s innate sense of facial aesthetics is required for obtaining outstanding results. Adapting techniques used for fat augmentation is helpful, regardless of the product used.

Augmentation of the zygomatic area highlights the malar eminence. When working on this area, one needs to focus on restoring or creating symmetry, not only by imitating the contralateral unit but also by keeping proportional cosmetic relations between the newly shaped structure and other facial landmarks.

Placement of fillers under the superficial musculoaponeurotic system provides significant expansion of the entire cheek unit, analogously to a pole that holds a tent up (see Fig. 18.2). This effect elevates the soft tissue around the corner of the mouth, slightly improving oral commissure grooves, possibly because the outer displacement of zygomatic muscles pulls the modiolus gently upwards. Likewise, filling the infraorbital area raises the levator of the upper lip muscle and associated fibrous tissues. Therefore, by working deeply in the mid-face we can expect natural improvement of marionette lines without directly injecting them. In addition to providing enough volumetric increase at rest, deep filling also reduces unattractive bulging of the augmented cheek when laughing.

Poly-L-lactic acid and hydroxylapatite

PLLA microspheres are US Food and Drug Administration (FDA) approved for injection as diluted aqueous suspension. The total volume of the actual particles is negligible; however, with time they become encapsulated by fibrous tissue providing diffuse augmentation. This explains why it is necessary to perform several injections spaced months apart before significant results are appreciated (Fig. 18.4). It also explains why some patients are more responsive then others, since this neotissue formation varies among individuals.

Figure 18.4 Poly-l-lactic acid (Sculptra^®, Dermik Aventis) augmentation of the mid-face (total of three vials, one per session, with average dilution of 6.3 mL/vial; second session 6 weeks later, third session 4 months after first treatment): (A, B, and E) before treatment; (C, D, and F) 3 months after last session. Note the textural improvement of the skin (red circle) and fine lines (arrowheads) in F.

PLLA is slowly degraded in a non-enzymatic hydrolytic fashion. Cosmetic results usually last for more than 18 months. Side effects are rare when the product is used highly diluted in the subcutaneous layer.

The remarkable ability of PLLA to induce fibrous tissue formation has the additional effect of providing a tensing effect, which can be visually and palpably appreciated by thickening of the skin in the treated areas (Fig. 18.4E and F).

Like PLLA, hydroxylapatite may induce neotissue formation – which accounts for augmentation lasting longer than its expected reabsorption. It has the additional advantage of providing immediate results. In order to avoid overcorrection, Tzikas recommended applying fine linear threads in the subcutaneous layer and massaging the injected sites immediately after treatment. The techniques described in the next session for volumizing HA augmentation can be adapted for hydroxylapatite. Dilution of hydroxylapatite with anesthetic solution is an FDA-approved technique that improves patient comfort.

Volumizing hyaluronic acid

Non-animal-derived HA preparations are frequently used for cosmetic improvement of facial lines. High-density monophasic or large-particle biphasic volumizing hyaluronic acid (VHA) is suitable for deep-tissue injection used in cheek augmentation, as described by Carruthers et al and Grover.

Augmentation of the cheeks with VHA is minimally invasive and provides immediate results that last from a few to more than 18 months. Specific product lines have received FDA approval for deep facial correction. The long safety profile of HA fillers is a major asset in facial augmentation but until recently their cost was unattractive to many patients.

Adaption of pan-facial fat transfer techniques to these products has revolutionized facial volumetric lifting. Impressive office-based cheek augmentation can now be comfortably achieved during a single session using small amounts of local anesthesia (Fig. 18.5). Touch-ups and maintenance injections can be easily performed at variable intervals, providing additional improvement and extending results.

Figure 18.5 Hyaluronic acid (HA) 20 mg/mL (Juvéderm^® Voluma, Allergan) augmentation of the mid-face (total bilateral volume = 5 mL; accordingly 3 mL was used undiluted in deep planes, and 1 mL was diluted with an additional 1 mL of 0.5% lidocaine solution in the superficial lateral cheek – dilution is off-label). A 23 G sharp cannula was used for the left side and 18 G blunt cannula for the right. HA 18 mg/ mL (Juvéderm^® Refine, Allergan) was used for the eyelid / cheek transition (total bilateral volume = 0.8 mL) using a 25 G blunt cannula: (A) before, (B) immediately after the procedure. (See video.)

VHA can be injected with sharp or blunt cannulas. This author thinks that sharp cannulas offer better sculpting potential. Notwithstanding, blunt cannulas seem to be safer, by decreasing the risk of tissue damage secondary to unintentional intravascular injection. Both techniques are demonstrated in the attached video. Similarly to more superficial use of HA, experience helps achieve more reliable results while minimizing risks.

Blunt cannula approach

Disposable blunt cannulas are easy to use, and may be provided with VHA. After anesthetizing the entry point, perforation of the skin is achieved with a no. 11 scalpel blade or sharp needle, so that the cannula can be inserted. Then, gentle dissection of soft tissue planes is usually well tolerated, allowing deposition of VHA even at distant points from the skin insertion. Blunt cannulas reduce, but do not abolish, intravascular injection risks. Filling the subcutaneous plane, as described by Cattin, may be easier for the novice; for the experienced, deeper cannula techniques offer excellent results.

Filling along the orbital rim with traditional, less cohesive monophasic or containing smaller particle biphasic HA improves tear troughs. The skin covering the tear troughs is usually quite flaccid. Undercorrection of this area is highly advised to avoid stigmatizing protusion and producing a bluish discoloration (Tyndall effect). Using thin blunt cannulas is recommended – blood vessels in this region anastomose with retro-orbital ones. Everyone performing cheek augmentation should learn how to manage complications. Table 18.2 lists possible complications and management advice (see also the studies by Duffy and Hedén).

Table 18.2 Side effects / complications from volumetric hyaluronic acid augmentation

CASE STUDY 1

Large-particle NASHA™ (non-animal stabilized hyaluronic acid) for Cheek Augmentation

A 75-year-old patient with a previous history of successful facial fat augmentation 4 years before (see Fig. 18.3) wished to complement the results with a less invasive procedure. She desired immediate results, but was not motivated by the inherent costs of using large amounts of hydroxylapatite or traditional hyaluronic acid (HA) products approved for facial use. More cost-effective alternatives were requested. Accordingly large-particle NASHA™, approved for breast augmentation in Europe and Brazil, was used for deep volumetric improvement of the mid-face and temples using the sharp needle approach described above for volumizing HA. In order to facilitate facial use, the HA was transferred from its original 10 mL syringe, under sterile technique, to 1 mL or 3 mL syringes by means of a Luer lock transfer. A total of 15 mL was subsequently injected with a 21 G needle. The patient was extremely satisfied with the results (Fig. 18.6). Anecdotally, over the past 2 years, this author has augmented the face of more than 20 patients, injecting up to 15 mL in a single session. Disclosure of the off-label indication was provided to every patient. This technique has yielded excellent cosmetic results, reducing costs without increasing side effects. These pilot cases warrant further investigation of the long-term applicability of using commercially available HA devices approved for other body parts to augment the face.

Figure 18.6 Same patient as in Figure 18.3, 4 years later. Off-label use of large-particle biphasic NASHA^™ (non-animal stabilized hyaluronic acid) (Macrolane^™ VRF20, Q-med) for deep plane augmentation of the mid-face and temples (total bilateral volume of 15 mL) using a 21 G sharp cannula: (A) before, (B) after 5 days, and (C) after 5 months.