Soft Tissue Implants and Fillers

Comparison of lyophilized glutaraldehyde-preserved bovine pericardium with different vascular prostheses for use as vocal cords implants: experimental study

This study compared the use of lyophilized glutaraldehyde-preserved bovine pericardium (LGPBP), polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), and Teflon felt (TF) as implants for vocal cords (VC) medialization and aimed to assess the endoscopic, macroscopic, and microscopic VC changes after medialization in a canine model. In 18 mongrel dogs, the right VC were medialized with LGPBP and the left were implanted as follows: Group I (n = 6): LGPBP and PTFE; Group II (n = 6): LGPBP and PET; Group III (n = 6): LGPBP and TF. Surgical handling of the implants was compared. Three months after surgery, macroscopic and microscopic changes of VC and implants were evaluated. LGPBP offered the best surgical handling (p = 0.005, Kruskal-Wallis). TF implants showed extrusion (p = 0.005, Kruskal-Wallis) and severe inflammation. All VC formed fibrous capsules around the implants; the ones developed by LGPBP implants were thinner (p = 0.001, ANOVA, Tukey). VC implanted with synthetic materials showed eosinophilic infiltration (p = 0.01, Kruskal-Wallis). We concluded that the LGPBP could be used as an implant for VC medialization because it is biocompatible, easy to handle and remove during surgical procedures, and nonabsorbable or extrudable and produces an inflammatory reaction similar to PTFE and PET.

Three types of dermal grafts in rats: the importance of mechanical property and structural design

Background

To determine how the mechanical property and micro structure affect tissue regeneration and angiogenesis, three types of scaffolds were studied. Acellular dermal matrices (ADM), produced from human skin by removing the epidermis and cells, has been widely used in wound healing because of its high mechanical strength. Collagen scaffolds (CS) incorporated with poly(glycolide-co-L-lactide) (PLGA) mesh forms a well-supported hybrid dermal equivalent poly(glycolide-co-L-lactide) mesh/collagen scaffolds (PMCS). We designed this scaffold to enhance the CS mechanical property. These three different dermal substitutes—ADM, CS and PMCSs are different in the tensile properties and microstructure.

Methods

Several basic physical characteristics of dermal substitutes were investigated in vitro. To characterize the angiogenesis and tissue regeneration, the materials were embedded subcutaneously in Sprague–Dawley (SD) rats. At weeks 1, 2, 4 and 8 post-surgery, the tissue specimens were harvested for histology, immunohistochemistry and real-time quantitative PCR (RT-qPCR).

Results

In vitro studies demonstrated ADM had a higher Young’s modulus (6.94 MPa) rather than CS (0.19 MPa) and PMCS (3.33 MPa) groups in the wet state. Compared with ADMs and CSs, PMCSs with three-dimensional porous structures resembling skin and moderate mechanical properties can promote tissue ingrowth more quickly after implantation. In addition, the vascularization of the PMCS group is more obvious than that of the other two groups. The incorporation of a PLGA knitted mesh in CSs can improve the mechanical properties with little influence on the three-dimensional porous microstructure. After implantation, PMCSs can resist the contraction and promote cell infiltration, neotissue formation and blood vessel ingrowth, especially from the mesh side. Although ADM has high mechanical strength, its vascularization is poor because the pore size is too small. In conclusion, the mechanical properties of scaffolds are important for maintaining the three-dimensional microarchitecture of constructs used to induce tissue regeneration and vascularization.

Conclusion

The results illustrated that tissue regeneration requires the proper pore size and an appropriate mechanical property like PMCS which could satisfy these conditions to sustain growth.

Prospective Evaluation of Office-Based Injection Laryngoplasty with Hyaluronic Acid Gel

Objectives:

The role of Juvederm Ultra Plus hyaluronic acid gel for use in injection laryngoplasty has not been well examined. The aim of this study was to prospectively assess the safety and clinical effectiveness of office-based injection laryngoplasty of Juvederm Ultra Plus gel in patients with glottic insufficiency.

Methods:

Thirty patients met the criteria for study inclusion and were treated with unsedated office-based injection laryngoplasty of Juvederm Ultra Plus gel over a 20-month period. The preinjection acoustic and aerodynamic measures, Voice Handicap Index, Glottal Function Index, and Dysphonia Severity Index were compared with values recorded at 1 and 4 months after injection.

Results:

Data for 27 patients were available for follow-up analysis at 1 month, and 12 patients' data were available at 4 months. Significant improvements, compared to preinjection levels (p < 0.02), were shown in all outcome measures at 1 and 4 months. One patient required intravenous steroid therapy for delayed glottic inflammation that resolved without permanent sequelae.

Conclusions:

The injection of Juvederm Ultra Plus gel is a relatively safe procedure that allows for short-term improvements in objective and subjective outcome measures of vocal function in patients with glottic insufficiency, provided the surgeon remains alert to the possibility of postprocedural injection site inflammation.

Etiology, prevention, and treatment of dermal filler complications

The availability of dermal fillers for multiple cosmetic indications has led to a dramatic increase in their application. Although fillers are generally regarded as safe tools for soft tissue augmentation, complications can occur. Therefore, to describe and review the complications associated with the currently-available dermal filling agents, the authors conducted a literature review in peer-reviewed journals and present the reported complication rates. They also describe current strategies to avoid, diagnose, and manage complications if they do occur.

The inhibition of collagenase induced degradation of collagen by the galloyl-containing polyphenols tannic acid, epigallocatechin gallate and epicatechin gallate

Collagen based cosmetic fillers require repeat treatments due to collagenase derived degradation of the filler in the intradermal injection site. The objective of this study was to investigate the inhibition of this degradation by the galloyl-containing compounds tannic acid, epigallocatechin gallate (EGCG), epicatechin gallate (ECG) and gallic acid (GA). A gel permeation chromatography assay was developed to quantitate the collagenase induced reductions in collagen molecular weight. The binding of the compounds to collagen was measured using HPLC. The stabilization of collagen was measured using Differential Scanning Calorimetry (DSC). Tannic acid, EGCG and ECG (but not GA) were found to strongly inhibit collagen degradation at concentrations in the low micromolar range. The compounds bound strongly to collagen and stabilized collagen. It is concluded that tannic acid, EGCG and ECG bind to collagen via extensive hydrogen bonding augmented by some hydrophobic interactions and prevent the free access of collagenase to active sites on the collagen chains.

Subcutaneous implants coated with tissue-engineered cartilage

OBJECTIVE

To investigate the ability to coat two alloplastic implants, porous high-density polyethylene (PHDPE) and expanded polytetrafluoroethylene (e-PTFE), with tissue-engineered cartilage (TEC) from human septal chondrocytes in a mouse model.

STUDY DESIGN

Prospective study.

METHODS

PHDPE and e-PTFE disks were coated with alginate impregnated with human septal chondrocytes and implanted into athymic nude mice. A control group consisting of PHDPE and e-PTFE disks coated with alginate only were implanted. Gross, histological, and biochemical characteristics of the TEC constructs were examined at 10 and 20 weeks following implantation.

RESULTS

One animal in the experimental group and one animal in the control group died. Implants coated with TEC were successfully generated in 18 (94.7%) mice in the experimental group (n = 19) and in zero (0%) of the control group (n = 17). The final weight of each harvested specimen decreased in the control group and increased in the experimental group, when compared with preimplant weight. Mean decrease in weight in the control group was greater at 20 weeks than at 10 weeks (P = .017). Mean increase in weight in the experimental group was greater at 20 weeks than at 10 weeks (P = .009). The diameter of the control group decreased, while the diameter of the experimental group was maintained. The reduction in diameter was less in the experimental group than in the control group at 10 (P = .018) and 20 weeks (P = .01). Gross and histological examination confirmed the formation of neocartilage, with characteristics similar to native cartilage, in the experimental group at 10 and 20 weeks. Glycosaminoglycan content in the experimental group at 20 weeks was approximately 80% of that measured in implanted human septal cartilage. Cartilaginous and fibrovascular ingrowth into implant pores was more extensive in the PHDPE than the e-PTFE experimental group.

CONCLUSIONS

Implants coated with TEC from human septal cartilage can be reliably produced in the athymic nude mouse model. Maintenance of shape, as measured by the conservation of construct diameter, is possible. Fibrovascular ingrowth and cartilage formation into the pores of the alloplastic implants was observed. This integration of a construct composed of a synthetic implant coated with TEC may improve the performance of alloplastic implants through better long-term fixation and increased resistance to infection.

Dermal filler agents: a practical review

PURPOSE OF REVIEW

Facial aging results from multiple microscopic (histopathologic) and macroscopic (anatomic) changes. Whereas skin care and traditional surgery have much to offer patients desiring cosmetic improvement, they can fail to adequately address certain signs of facial aging. Soft-tissue augmentation with dermal fillers can successfully address these signs of aging by filling soft-tissue defects caused by age, scar formation, or disease. All dermal fillers aim to achieve the same goal: long-lasting soft-tissue augmentation without side effects. Each dermal filler preparation available for patient use has unique compositions and characteristics that impact its proper handling, therapeutic results, potential complications, and, ultimately, its ideal use. This review surveys the currently available preparations for soft-tissue augmentation.

RECENT FINDINGS

A review of the medical literature and manufacturers' information are included for dermal fillers currently approved for use by the US Food and Drug Administration. The composition, use, and potential limitation of each available preparation are reviewed.

SUMMARY

Dermal filling agents offer an excellent option for management of certain facial cosmetic changes. Since a wide range of products with significantly different characteristics is available, the treating physician should have sound knowledge of them all.

Consensus recommendations for soft-tissue augmentation with nonanimal stabilized hyaluronic acid (Restylane)

The American Society for Aesthetic Plastic Surgery recently reported that there were nearly 12 million cosmetic procedures (2.1 million surgical and 9.7 million nonsurgical) performed in the United States in 2004. Almost 900,000 of the nonsurgical procedures were soft-tissue augmentation procedures using hyaluronic acid fillers. Restylane (Medicis Aesthetics, Inc., Scottsdale, Ariz.), nonanimal stabilized hyaluronic acid, was approved for use in the United States in December of 2003. Although the use of all fillers increased from 2003 to 2004, use of hyaluronic acid fillers increased nearly 700 percent. The dramatic increase in all cosmetic procedures reflects the growing trend, especially with increasing job competition, to maintain a youthful lifestyle and appearance. Basic recommendations for aesthetic use of Restylane were established based on short- and long-term efficacy and safety studies (Medicis Aesthetics, package insert). With the widespread and growing use of Restylane, a cross-sectional panel of experts with extensive clinical experience, including cosmetic dermatologists and surgical specialists (cosmetic, plastic, and ocular), convened to develop consensus guidelines for the use of Restylane. This supplement reviews the aesthetic affects of aging on the face, the role of fillers in facial soft-tissue volume replacement, and general principles for the use of Restylane, including patient comfort and assessment techniques. Specific recommendations for Restylane use in each potential target area, including type of anesthesia, injection techniques, volume for injection, use in combination with other procedures, and expected longevity of corrections, are provided. Techniques for optimizing patient outcomes and satisfaction and for minimizing and managing expected problems and potential complications are described.