Category Archives: Assignments

Minimum Assembly Bipolar Instrument

Complex medical devices, such as the EndoWrist, are difficult to manufacture and can often take up to a few week to assemble. In an effort to improve the manufacturability and assembly, in this assignment it is the aim to develop a medical instrument that minimizes assembly.

If you are interested in this assignment, please contact: Aimée Sakes, a.sakes@tudelft.nl

3D printed wasp-ovipositor replica: reverse engineering approach (CLOSED)

In nature, several species of parasitoid wasps have a thin and flexible needle-like structure, called ovipositor, which is used to deposit eggs in a host (e.g., a larva) hidden into tree trunks or fruits. The wasp ovipositor consists of three segments, called valves, longitudinally connected that can slide along each other.  The animals can drill in different substrates by actuating the valves in a reciprocal motion and steer by changing the relative positions of the valves during probing (i.e. protracting and retracting of the valves).

We are currently developing a novel steerable needle for minimally invasive interventions inspired by the wasp-ovipositor. However, the steering mechanisms used by the animal is not yet fully understood.

The project will focus on understanding how the steering mechanism works and which characteristics of the ovipositor play a relevant role.

The student will use detailed 3D images of different ovipositors to design several replicas of the wasp ovipositor in larger scale with 3D printed techniques. The prototypes will be tested with an experimental facility where motion pattern and speed can be controlled. The ovipositors will be inserted in gelatine of different concentration to study the design parameters effecting the steering mechanism.

Contact: Marta Scali, m.scali@tudelft.nl

Picture adapted from “Braconid Wasp Ovipositing” by Katja Schulz is licensed under CC BY 2.0.

Automatic design and manufacturing of upper limb prosthetic sockets for developing countries

Comfort and functionality of upper limb prosthetics is highly dependent on socket performance. Correct anatomical fit is therefore of paramount importance for prosthetic designs. We believe that the complex design process of prosthetic sockets can be achieved automatically using accurate anatomical models of the stump. With the increasing advance in smartphone technology it is possible to reconstruct digital models based on camera information. We plan to explore current technologies for generating 3D digital models from multiple 2D photos and assess such techniques to stablish a framework in which smartphone technology can be used to generate 3D computer models of upper limb stumps. Using precise geometry of the stump and current CAD technologies it is possible to create a socket design that fits accurately into the residual limb. We plan to adopt such process to build fully working prosthetic sockets using 3d printing technology for developing countries.

Contact: Juan Cuellar, J.S.CuellarLopez@tudelft.nl

Design of an endoluminal ovipositor-device (CLOSED)

During colonoscopy procedures an endoscopic device is inserted into the patient and pushed through the colon with consequential discomfort to the patient.  Self-propelling devices that are able of moving through a lumen without the need of external push could be beneficial for these applications. Research in this topic is ongoing, but no successful solutions have yet been discovered.

At TU Delft a former master student (Perry Posthoorn) developed a self-propelled device inspired by the mechanism of the ovipositor of the wasp. The ovipositor is a needle-like structure which consists of three elements that can slide along each other. By means of a reciprocal movement of the elements the wasp is able to insert the ovipositor through a substrate. The reciprocal sliding mechanism of multiple elements has inspired the design of our ovipositor-device.

Preliminary tests have shown that the device is able to move through an ex-vivo porcine colon, although at extremely slow speed due to a sub-optimal internal construction of the device.

The aim of this graduation project  is to develop a strongly improved endoluminal device aiming at maximizing propulsion speed at minimal internal complexity with the final aim to make a revolutionary new system suited for disposable use.

For more information contact Marta Scali (m.scali@tudelft.nl).

Shockwaves for Puncturing through Occlusions (CLOSED)

Chronic Total Occlusions (CTOs) are currently the last frontier for cardiovascular surgery. CTOs are defined as heavily calcified occlusions in the vascular system of the heart that slowly form over time and are at least three months old. The preferred treatment option of CTOs is a so-called Percutaneous Coronary Intervention (PCI). Unfortunately, in many occasions PCI is ineffective as the guidewire is not able to cross the CTO due to lack of stiffness of the guidewire and the less than favourable properties of the CTO. Therefore, the success rate of these kinds of interventions is relatively low, which in turn has led to the tendency to treat these kinds of lesions medically.

To improve the success rate of these kinds of interventions it is, therefore, necessary to develop a new tool that is able to cross the CTO without buckling. From this, the idea arose to use shockwaves to puncture through CTOs. Shockwaves are used in the animal kingdom to strike through hard shells and prey capture by, for example, the Mantis Shrimp. They are particularly effective in fluidic environment such as the blood vessels and are, therefore, a good candidate for prototype development.

This research project will entail a literature study where the use of shockwaves in the animal kingdom and other shockwave applications and/or instruments is investigated, and a graduation project where innovative shockwave tool for puncturing the proximal cap of chronic total occlusions is developed.

Contact: Aimée Sakes, a.sakes@tudelft.nl

Design of A Flexible Tissue Removal Device for Skull Base Surgery

Cushing’s disease is a neurological disorder caused by the loss of dopamine secretion in and near the pituitary gland. Unlike in human Cushing’s disease, where surgical removal of the pituitary tumors is a common treatment modality, in horses oral treatment is the treatment of choice. This oral treatment does not provide a long-term solution to the disease, as it is focused on symptom reduction and does nothing to fight the actual cause of the disease.

In collaboration with the department of Veterinary medicine Utrecht, a new paradigm of surgical treatment of Cushing’s disease in horses has been developed that uses the vascular system in combination with an innovative flexible morcellator to reach the pituitary gland. This flexible morcellator incorporates a rigid tip with a resection tool and a flexible shaft, which incorporates a cable drive element, used for actuating the resection tool, and a central tissue transportation lumen.

Further development of this device is necessary before clinical use can commence. Redevelopment should focus on miniaturisation, improving the cutting blade design, and adding a means of visualizing the pituitary tumors.

We are currently also exploring the possibility to redesign this instrument for human surgery.

Contact: Aimée Sakes, a.sakes@tudelft.nl