Biocompatible Interface-Modified Tissue Engineering Chamber Reduces Capsular Contracture and Enlarges Regenerated Adipose Tissue

Strategies for Constructing Tissue-Engineered Fat for Soft Tissue Regeneration

BACKGROUND

Repairing soft tissue defects caused by inflammation, tumors, and trauma remains a major challenge for surgeons. Adipose tissue engineering (ATE) provides a promising way to solve this problem.

METHODS

This review summarizes the current ATE strategies for soft tissue reconstruction, and introduces potential construction methods for ATE.

RESULTS

Scaffold-based and scaffold-free strategies are the two main approaches in ATE. Although several of these methods have been effective clinically, both scaffold-based and scaffold-free strategies have limitations. The third strategy is a synergistic tissue engineering strategy and combines the advantages of scaffold-based and scaffold-free strategies.

CONCLUSION

Personalized construction, stable survival of reconstructed tissues and functional recovery of organs are future goals of building tissue-engineered fat for ATE.

Techniques and Innovations in Flap Engineering: A Review

Currently, the gold standard for complex defect reconstruction is autologous tissue flaps, with vascularized composite allografts as its highest level. Good clinical results are obtained despite considerable obstacles, such as limited donor sites, donor site morbidity, and complex operations. Researchers in the field of tissue engineering are trying to generate novel tissue flaps requiring small or no donor site sacrifice. At the base of existing technologies is the tissue’s potential for regeneration and neovascularization.

3D Culture Promotes Secretion of Extracellular Matrix Structure Fat Flap with Lipoaspirates in Vitro

Adipose tissue engineering represents a possible solution for large-volume soft-tissue reconstruction. Although there have been several reports on the construction of tissue-engineered fat (TEF) flaps in vivo and in vitro, each condition has various limitations. Thus, we developed a novel approach for engineering fat tissue using a 3D culture system. We used different volumes of lipoaspirates to fill the same tissue engineering chamber (30%, 50%, 80%, and 100% volume/space ratio) for different periods (3, 5, 7, and 14 days) to determine whether lipoaspirates can form structural fat tissue in vitro. We then studied the histological structure and extracellular matrix of the tissue formed in vitro. We selected engineering tissue-like fat of the 80% volume/space ratio group cultured for 7 days to be subcutaneously implanted into mice for up to 3 months, and lipoaspirates without structure in vitro were used as a control. The lipoaspirates from the 80% volume/space ratio group cultured in vitro formed TEF-like tissue, which increased in small adipocytes and extracellular matrix with time until becoming stable on day 7. The live/dead test showed that the tissue cultured in vitro remained viable until day 7. Immunofluorescence staining results revealed that the collagen I and IV content increased over time. Moreover, after grafting, "self-assembly" fat had higher volume retention, better vascularization, fewer oil droplets, and less fibrosis than the lipoaspirates without structure in vitro. Therefore, our results demonstrate that lipoaspirates filled in tissue engineering chamber can be cultured in vitro and can "self-assemble" into TEF-like tissue. Furthermore, the "self-assembly" fat tissue produced better grafting results than those of lipoaspirates without structure in vitro.

Treatment of Severe Postburn Contracture of the Elbow via Distraction With External Circular Frame in Pediatric Patient

BACKGROUND

Although external circular frame (ECF) has been widely used for the correction of knee and ankle deformities, few studies reported the use of ECF for the treatment of severe postburn elbow contracture and stiffness (SPECS). The purpose of this retrospective study was to investigate the effectiveness and safety of the distraction using ECF in treating SPECS.

METHODS

After institutional review board approval, we implemented a retrospective single-center case series study composed of consecutive patients treated for SPECS at Chinese PLA General Hospital between January 2010 and January 2018. After scar release and skin grafting, distraction with ECF was performed for 4 to 6 weeks, and the frame was retained for 2 more weeks before removal. Four weeks of splinting and at least 1 year of rehabilitation were recommended. Patient demographics, active and passive range of motion (ROM) of the elbow at different time points (preoperative, postdistraction, and final follow-up), and complications were collected from the electronic medical record. The primary outcome was the long-term improvement of the ROM. Other outcomes included complications and recurrence.

RESULTS

The ECF was used to treat SPECS in 6 patients (3 males and 3 females, average age of 11.7 ± 2.6 years). Scar release and distraction with ECF significantly increased both active (from 3° preoperative to 38.7° postdistraction) and passive (from 3.5° preoperative to 48.3° postdistraction) ROM over an average distraction duration of 5.2 weeks. The long-term improvement of active and passive ROM was 38° ± 13.4° and 46° ± 14.7°, respectively, over a median follow-up of 4.1 years. Pin-tract infection occurred in 2 patients and were treated with local wound care and oral antibiotics. A tendon readhesion developed in 1 of the 6 patients because of noncompliance with splinting and physiotherapy, and was treated with revision surgery.

CONCLUSIONS

The 3C strategy (i.e., contracture release, coverage of the defect with skin grafting, and correction of articular angle with gradual distraction using the ECF) is able to increase the ROM with minor complications. We recommend distraction with ECF as part of the treatment arsenal, particularly for severe contractures in which 1-stage correction is unfeasible because of considerable soft tissue shortening.