Flexible Endovascular Horse Morcellator

Cushing’s disease is a naturally occurring progressive pituitary disorder that can be found in multiple species, including dogs, donkeys, horses, and humans. In horses, treatment of Cushing’s disease is aimed at controlling and reducing the severity of the clinical signs using oral medication, rather than removing the tumor from the pituitary gland (which is often performed in humans), due to the fact that to date surgical removal has been technically impossible. Therefore, a new paradigm in pituitary surgery in horses was developed in close collaboration with expert veterinarian Johannes van der Kolk of the Faculty of Veterinary Medicine of the University Utrecht. In contrast to the human vascular system, multiple superficial veins in the horse, like the facial vein, can provide direct access to the pituitary gland. This superficial vein was used to guide an innovative flexible morcellator towards the pituitary gland. Once arrived at the pituitary gland, this morcellator uses a flexible drive cable to actuate a rotating cutting blade at the tip of the instrument to resect and subsequently remove the pituitary tumors. First cadaver experiments have proven successful in inserting this instrument and removing pieces of pituitary tumor. Further research needs to be done before clinical application of the instrument can take place. Nevertheless, continued development of this approach may in time improve the quality of life of horses suffering from Cushing’s disease.

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Biopsy Harvester – High-Speed Tissue Cutting

Current minimally invasive laparoscopic tissue harvesting techniques for pathological purposes involve taking multiple imprecise and inaccurate biopsies, usually using a laparoscopic forceps or other assistive devices. Potential hazards, e.g. cancer spread when dealing with tumorous tissue, call for a more reliable alternative in the form of a single laparoscopic instrument capable of repeatedly taking a precise biopsy at a desired location. Therefore, the aim of this project was to design a disposable laparoscopic instrument tip, incorporating a centrally positioned glass fibre for tissue diagnostics; a cutting device for fast, accurate and reliable biopsy of a precisely defined volume and a container suitable for sample storage.

Inspired by the sea urchin’s chewing organ, Aristotle’s lantern, and its capability of rapid and simultaneous tissue incision and enclosure by axial translation, we designed a crown-shaped collapsible cutter operating on a similar basis. Based on a series of in vitro experiments indicating that tissue deformation decreases with increasing penetration speed leading to a more precise biopsy, we decided on the cutter’s forward propulsion via a spring. Apart from the embedded spring-loaded cutter, the biopsy harvester comprises a smart mechanism for cutter preloading, locking and actuation, as well as a sample container.

A real-sized biopsy harvester prototype was developed and tested in a universal tensile testing machine at TU Delft. In terms of mechanical functionality, the preloading, locking and actuation mechanism as well as the cutter’s rapid incising and collapsing capabilities proved to work successfully in vitro. Further division of the tip into a permanent and a disposable segment will enable taking of multiple biopsies, mutually separated in individual containers. We believe the envisioned laparoscopic opto-mechanical biopsy device will be a solution ameliorating time demanding, inaccurate and potentially unsafe laparoscopic biopsy procedures.

 

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