15.3 Background to Injectable Soft-Tissue Fillers

superior sulcus and an increased upper eyelid pre-tarsal show. The hollow superior sulcus may be medially only (“A-shaped” hollow) or more generalized. There can also be associated upper eyelid ptosis, with or without secondary compensatory brow elevation. The lower eyelid may appear retracted, particularly laterally, and there may be hollows, both medially in the tear trough region and laterally, revealing the underlying inferior orbital rim. Anophthalmic patients with orbital volume loss may have additional complaints about prosthesis instability, caused by lower eyelid stretching from longstanding use of a bulky prosthesis, used to compensate for their fundamental lack of orbital volume. This combination of relative enophthalmos, hollow superior sulcus, increased upper eyelid pre-tarsal show with ptosis and lower eyelid laxity has traditionally been termed the “post-enucleation socket syndrome” (PESS). Typical presentations of orbital volume loss are illustrated in Fig. 15.1.

15.2.4Features of Periorbital Volume Loss

Periorbital volume loss can present in a wide range of ways reflecting the many etiologies involved. Bony loss or hypoplasia of the maxilla results in flat cheeks and relative globe proptosis, producing what is termed a “negative facial vector” [50]. This is often associated with lower eyelid retraction and lagophthalmos. If significant, this can cause symptoms of epiphora and reflex tearing. Localized subcutaneous atrophy will leave a well-defined inferior periorbital hollow, whilst the di use periorbital volume loss seen in facial aging leads to loose skin, lack of convex facial contours and unmasking of the underlying bony and ligamentous anatomy [17, 21, 22, 50, 64]. In the lower eyelid this results in prominence of the lower eyelid fat pad and inferior orbital rim [31]. Such “bags” and adjacent tear trough hollows often cause esthetic concern.

In the upper eyelid soft-tissue atrophy leads to medial or generalized hollowing of the superior sulcus and an increased upper eyelid pre-tarsal show. A similar appearance may arise as a result of dehiscence of the levator aponeurosis or after excessive fat removal during blepharoplasty. Associated upper eyelid dermatochalasis in this setting simply reflects upper eyelid volume deflation. In the brow region, deflation of the sub-brow fat pad and possible supero-temporal orbital rim remodeling results in lateral brow ptosis. This further contributes towards upper eyelid hooding [13]. Soft-tissue atrophy in the temple region further contributes to a lack of support for the lateral brow. Temple volume loss also causes skeletalization of the orbital rim and clipping of the tail of the brow in the frontal view (Fig. 15.1e and f).

15.3Background to Injectable Soft-Tissue Fillers

15.3.1Historical Perspective on Volume Replacement

Orbital and periorbital volume loss has traditionally been managed surgically by way of implants and grafts. Orbital implants include ball implants for anophthalmia, orbital floor implants and dermis-fat grafts, whilst those used in the periocular region include malar implants [25], dermis-fat grafts, lumbrical fat grafts [26], and “pearl fat” grafts [54, 56]. More recently, autogenous fat grafting, using fat harvested in a manner similar to liposuction, has been successfully applied to the periocular region [4, 13, 15, 16, 40]. However, for the large part, these procedures require general anesthesia and carry the potential for significant surgical morbidity and complications, including hemorrhage, infection, and implant extrusion. In addition, fat grafts are prone to atrophy and hypertrophy making them somewhat unpredictable [46].Although invaluable for large volume defects, these implants are not easy to titrate to the exact degree and location of volume loss making them unsuitable for more subtle volume deficiencies. This is of particular relevance to the periocular region where small asymmetries in volume are very noticeable and are a concern for many patients.

15.3.2Advantages of Injectable Soft-Tissue Fillers

Injectable soft-tissue fillers have provided a solution to the problems of surgical volume replacement. Their advantages include precise soft-tissue placement, titratable volume augmentation, the ability to be performed in the o ce, biocompatibility, low down-time, minimal morbidity, high safety and, in most cases, potential reversibility [12, 20]. Their principal disadvantage is a limited duration, ranging between six months and a few years depending on the product type. However, for many patients this can be an advantage as it allows volume enhancement to be altered over time depending on the desired look and changing facial structure.

15.3.3Complications of Injectable Soft-Tissue Fillers

Overall, soft-tissue fillers have an excellent safety record and have been extensively used for the treatment of facial rhytids and wrinkles over the last decade [42]. However,