2017-18 HSC Section 4 Green Book

Volume 135, Number 6 • Regenerative Materials

the longevity of their filling effect before degra- dation by the body is directly proportional to the presence of these two components. 65 In light of this, there is strong evidence that a synthetically generated filler (poly- l -lactic acid) can outper- form injectable human collagen for the treatment of rhytides. 51 Their applications are widespread; however, research shows that their results are extremely variable. Similarly, fat graft survival in the setting of soft-tissue volume replacement or augmentation is also extremely variable, with retention rates ranging from 25 to 80 percent. 53 In addition, complications can occur in the hands of the inex- perienced provider and include facial cellulitis, abscess formation, and inflammatory nodules. 52 In extreme cases, severe complications include soft-tissue necrosis and blindness. 51 The lack of predictability in fat graft outcomes combined with the regulatory restrictions for cellular graft enrich- ment provides a challenge for soft-tissue filling. A predictable, stable regenerative mix derived from lipoaspirate is being earnestly sought at present, and is likely to considerably impact this field. EMERGING MODALITIES We live in very exciting times with regard to biomaterials and regenerative medicine. We are seeing a shift toward personalized medicine as new technologies are realized. Kølle et al. dem- onstrated a 65 percent improvement in fat graft survival after 4 months when lipoaspirate was supplemented with autologous adipose-derived

including septal, auricular, or costal cartilage. These materials are often limited in quantity, require a donor harvest site, and increase surgi- cal time. Although the majority of publications regarding the use of biomaterials in rhinoplasty are experimental reports, Sherris et al. published a case series where they found applications for the use of acellular dermal matrix in rhinoplasty as a septal implant, for dorsal augmentation or for camouflaging the nasal dorsum and tip. Although acellular dermal matrix did not provide structural support, the group reported minimal complica- tions and no cases of infection, seroma forma- tion, septal perforation, significant resorption, or extrusion among 51 patients. 37 Of the studies we reviewed, the data associ- ated with cosmetic procedures were more likely to be prospective and randomized because of the elective nature of cosmetic procedures (Table 2). Injections with soft-tissue fillers are the second most common minimally invasive procedure per- formed by plastic surgeons behind botulinum toxin type A. 54 The most frequently used fillers are composed of hyaluronic acid and nonanimal stabilized hyaluronic acid, followed by calcium hydroxylapatite and poly- l -lactic acid (Table 4). Their strength, ability to maintain structural integrity, and overall stability within the body are attributed primarily to the extent of molecular cross-linking and the presence of hyaluronic acid; COSMETIC AND SOFT-TISSUE REPLACEMENT

Table 4. Injectable Types and Different Applications Product Type Derivation

Application

Duration of Effect

CosmoDerm, CosmoPlast (Inamed Aesthetics, Santa Barbara, Calif.) Cymetra (LifeCell Corp., Branchburg, N.J.)

Human, highly purified collagen

Cosmetic: correction or wrinkles or scars

3–6 mo

Human, micronized AlloDerm Cosmetic: correction of nasolabial folds, lips, acne, and scars

3–9 mo

Restylane (Medicis, Scottsdale, Ariz.)

Synthetic, hyaluronic acid gel

Cosmetic: wrinkle reduction, lip augmentation, nasolabial folds, and glabellar creases Cosmetic: correction of moderate to severe facial wrinkles Cosmetic: correction of nasolabial folds, vertical lip lines, acne scars, marionette lines, and restoring volume in cheeks Cosmetic: suitable for use in any wrinkles Cosmetic: treatment of nasolabial folds, glabellar, and corner-of- mouth wrinkles Treatment of HIV facial lipoatrophy

6–12 mo

Hylaform (Inamed)

Avian, cross-linked hyaluronic acid

3–4 mo

Radiesse (BioForm Medical, Inc., San Matteo, Calif.)

Synthetic calcium hydroxyapatite

~2 yr

Synthetic, poly- l -lactic acid

1–2 yr

Sculptra (Dermik Laboratories, Berwyn, Pa.) Juvéderm (Allergan, Inc., Santa Barbara, Calif.) ArteCol, ArteFill (Artes Medical, San Diego, Calif.)

Derived from Streptococcus , free hyaluronic acid Polymethylmethacrylate micro- spheres in bovine collagen

9–12 mo

~2 yr

HIV, human immunodeficiency virus.

6