The Future of Microsurgery: Vascularized Composite Allotransplantation and Engineering Vascularized Tissue

Abstract

Background: Microsurgical techniques have revolutionized the field of reconstructive surgery and are the mainstay for complex soft tissue reconstruction. However, their limitations have promoted the development of viable alternatives. This article seeks to explore technologies that have the potential of revolutionizing microsurgical reconstruction as it is currently known, reflect on current and future vascularized composite allotransplantation (VCA) practices, as well as describe the basic science within emerging technologies and their potential translational applications.

Methods: A literature review was performed of the technologies that may represent the future of microsurgery: vascularized tissue engineering (VCA) and flap-specific tissue engineering.

Results: VCA has shown great promise and has already been employed in the clinical setting (especially in face and limb transplantation). Immunosuppression, logistics, cost, and regulatory pathways remain barriers to overcome to make it freely available. Vascularized and flap-specific tissue engineering remain a laboratory reality but have the potential to supersede VCA. The capability of creating an off-the-shelf free flap matching the required tissue, size, and shape is a significant advantage. However, these technologies are still at the early stage and require significant advancement before they can be translated into the clinical setting.

Conclusion: VCA, vascularized tissue engineering, and flap-specific bioengineering represent possible avenues for the evolution of current microsurgical techniques. The next decade will elucidate which of these three strategies will evolve into a tangible translational option and hopefully bring a paradigm shift of reconstructive surgery.

Keywords: composite tissue transplantation; tissue engineering; vascularized composite allotransplantation.

Fig. 1

Schematic illustration of the experimental setup introduced by Fichter et al. A motor-driven roller pump transports pre-heparinized autologous blood to an oxygenator membrane. The oxygenated blood goes through an arterial reservoir and flows into the radial forearm flap, while the venous return is collected in another reservoir connected to a pressure gauge. If the pressure in the circuit exceeds a certain threshold, the pressure will be evened up by opening a shunt between the arterial and venous reservoirs. Both reservoirs have a function as bubble traps. The illustration was created with BioRender.com.

Fig. 2

Proposed flow for engineering complex tissue.