A World Update of Progress in Lower Extremity Transplantation: What's Hot and What's Not.

ABSTRACT: The field of vascularized composite allotransplantation (VCA) is the new frontier of solid organ transplantation (SOT). VCA spans life-enhancing/life-changing procedures such as upper extremity, craniofacial (including eye), laryngeal, tracheal, abdominal wall, penis, and lower extremity transplants. VCAs such as uterus transplants are life giving unlike any other SOT. Of all VCAs that have shown successful intermediate- to long-term graft survival with functional and immunologic outcomes, lower extremity VCAs have remained largely underexplored. Lower extremity transplantation (LET) can offer patients with improved function compared to the use of conventional prostheses, reducing concerns of phantom limb pain and stump complications, and offer an option for eligible amputees that either fail prosthetic rehabilitation or do not adapt to prosthetics. Nevertheless, these benefits must be carefully weighed against the risks of VCA, which are not trivial, including the adverse effects of lifelong immunosuppression, extremely challenging perioperative care, and delayed nerve regeneration. There have been 5 lower extremity transplants to date, ranging from unilateral or bilateral to quadrimembral, progressively increasing in risk that resulted in fatalities in 3 of the 5 cases, emphasizing the inherent risks. The advantages of LET over prosthetics must be carefully weighed, demanding rigorous candidate selection for optimal outcomes.

Injectable Pectin-Alginate Hydrogels for Improving Vascularization and Adipogenesis of Human Fat Graft.

Autologous fat grafting (AFG) is the most prevailing tool for soft tissue regeneration in clinics, although efficiency is limited to unpredictable volume resorption due to poor vascularization and eventual necrosis. This study sought to improve the AFG efficiency using a hydrogel as a carrier for human fat graft (F) with and without platelet-rich plasma (PRP). PRP is clinically well known for the local release of several endogenous growth factors and has been in clinical use already. A human-fat-graft-encapsulated pectin-alginate hydrogel (FG) was developed and characterized. PRP was added to F to develop a human fat graft with PRP (FP). FP was admixed with a pectin-alginate hydrogel to develop FGP. FG and FGP showed the smooth injectable, elastic, and shear-thinning properties. FG and FGP groups showed enhanced cell viability and proliferation compared to the control F in vitro. We also investigated the in vivo angiogenesis and neo-adipogenesis ability of F, FG, FGP, and FP in nude mice after subcutaneous injection. After 2 and 4 weeks, an MRI of the mice was conducted, followed by graft explantation. The explanted grafts were also assessed histologically and with immunohistochemistry (IHC) studies. MRI and histology results revealed better vascularity of the FG and FGP system compared to fat graft alone. Further, the IHC studies, CD 31, and perilipin staining also revealed better vasculature and adipogenesis of FG and FGP systems. These results indicate the enhanced angiogenesis and adipogenesis of FG and FGP. Thus, developed pectin-alginate hydrogel-based fat graft systems FG and FGP replenish the native microenvironment by mediating angiogenesis and adipogenesis, thereby maximizing the clinical outcomes of autologous fat grafting.

Gastro-omental free flap for reconstruction of tongue defects.

OBJECTIVES: The purpose of this paper is to report the technique and outcomes of the use of gastro-omental free flap reconstruction in glossectomy defects. MATERIALS AND METHODS: This is a prospective case series of 9 patients of tongue squamous cell carcinoma, who underwent either subtotal or partial glossectomy and reconstruction with gastro-omental free flap. The flap anatomy, surgical technique and the outcomes including the swallowing and speech are presented. RESULTS: Five patients underwent partial glossectomy and 4 had sub-total glossectomy. The median age was 43 years; and the median follow up was 11.4 months. Laparoscopic harvest was done in 8 patients. There was one flap loss. Seven patients underwent postoperative radiotherapy. Functional evaluation was done in 5 patients who were disease free. Four could tolerate soft diet orally, one patient was on liquid to pureed diet. Speech was intelligible in 4. None of the patients had any complications related to laparotomy or laparoscopy. CONCLUSION: Gastro-omental flap provided a secretory mucosal surface and was beneficial in the saliva depleted patients post radiotherapy. The laparoscopic harvest of this flap has minimized donor site morbidity. One patient had a flap loss. Two patients reported superficial ulcerations on the surface, one of them had to undergo surgical debulking to correct it while the other healed with conservative measures. Speech and swallowing outcomes of the reconstructed tongue was good, especially in patients with partial glossectomy. The reconstructed gastric mucosal flaps tolerated the adjuvant radiation well.