DelNero_wk2

Another storm of clinical and research adventures filled the week. The most dramatic case, a free-flap autograft for a patient with a large diabetic foot ulcer, provided first-hand insights to the challenges posed by microvascular surgery and design criteria for tissue-engineered pre-vascularized constructs. However, more important than the project specifications, this week I learned to appreciate the value of reliability in the OR. Whereas in Ithaca, I might successfully fabricate a fully endothelialized microvessel in 1% of my attempts, Dr. Spector demands dramatically higher results before implementing any new technology in a procedure. This was most obvious in the suturing of the veins, which requires 12 microscopic pins to perfectly align with their receiving sockets. Any obstructions of the anastomosis could generate thrombosis and cause the flap to fail. Demonstration of robustness is an indispensable paradigm in surgery, especially micro-surgery.

This particular surgery was very informative for my summer research project, which may eventually include connecting tissue-engineered blood vessels to rat vasculature. Although I have produced such vessels in Ithaca, I never previously considered the problems of attaching these devices to the host circulatory system. Witnessing the strategies and technologies that currently exist for plumbing free-flaps illustrated the challenges associated with this obstacle. Meanwhile, attempts to generate TE thick tissues without addressing this step will be largely useless. As Dr. Spector repeatedly informs us, vasculature is critical for tissue survival. The interface between fully-biological surrogate vasculature and host vessels will be an interesting engineering problem, and like the free-flap operation, will require almost perfect reliability.

Meanwhile, I have had moderate success in my current project aim, which comprises the fabrication and implantation of micropatterned collagen scaffolds. This week I generated 12 discs which contained 0, 1, or multiple channels. Theoretically, the channels will facilitate cell invasion from the periphery toward the center of avascular wounds, such as exposed bone or synthetic hardware. Alone, even small openings on these areas would never heal due to lack of vasculature. Our constructs will hopefully facilitate the lateral invasion of cells and vessels from surrounding healthy tissue. Next week I will image the discs to see how well the fabrication technique was able to produce channels in the collagen.

It is amazing that another week has already gone by. I am starting to realize that, like the surgeon, each moment I have here at WCMC will be precious!