SurGuide is a new company developing a medical product called the MarginGuide. SurGuide aims to improve the results of oral cancer surgery. The development of this product is relevant because each year around 300.000 new patients are worldwide diagnosed with oral cavity cancer. The primary treatment for oral cancer is surgery but mortality is high as the 5-yr survival rate after surgery is less than 50%.
The main goal of the surgery is to remove the complete tumor with a safe margin of healthy tissue around the tumor to be sure that the entire tumor is removed from the body. Nowadays, surgeons only use their feeling and visual capabilities to distinguish tumor from healthy tissue. This poor availability of equipment results in the fact that most of the times tumor is only partially removed from the body. This results in a poorer prognosis on quality of life for the patient. Technology is needed to support the surgeon.
Therefore this thesis focussed upon the design of a functional and user-friendly Raman-spectroscopic instrument for the rapid assessment of the surgical margin in a tumor, providing surgeons with adequate information to ensure complete tumor removal. Raman-spectroscopy is an optical technology, which can differentiate tumor from healthy tissue.
The chosen design approach consist out of four design phases. In the first phase, Discover, it is analysed what, according to surgeons and pathologists, is a functional and user-friendly guided surgery tool. It has been found that the optical fiber needle should penetrate the tissue while performing a Raman-spectroscopic measurement. The device should provide over 10 mm depth the margin with an accuracy of 1mm. Also, the positioning, repositioning and stabilizing of the probe onto the tissue should be comfortable and safe to the user.
The second phase is called the Develop phase. In this stage and by means of creative methods, ideas have been generated. First, it has been decided to select a handheld design instead of a holder. A holder would be less user-friendly and would have more manufacturing complexities. Furthermore, it has been found that the user group prefers a small precision grip. Based upon these two initial decisions, two concepts have been proposed to potential users and the project team. These concepts differ in two ways 1) How the needle is moved into the tissue and 2) How the tool provides the distance between the needle-tip and the surface. In one concept, the needle is moved manually and the depth of the needle is determined by a distance scanner/sensor. In the other concept, a motor is selected which moves the needle into the tissue. This motor also controls the depth in which the needle is penetrated into the tissue.
The third phase has been the Experiment phase in which the concept are tested on their functionality and usability. Components are tested on its ability to determine the needle depth for 1 mm accurate. Also, various users tests with potential users show that preference goes to the concept with the motor. Also, by the insights obtained in the user tests, the form of the probe is made smaller and more pen shaped. The technique for this concept, the servo motor, can be used for the next prototype of the MarginGuide.
Also part of the Experiment phase, has been the tests of several prototypes. These tests were performed to provide a first suggestion on the manufacturability and maintainability of the probe.
The prototypes demonstrated an option on how the motor inside the probe housing can be connected to facilitate the movement of the needle. This prototype shows the designed bar, which transfers the movement of the motor to the needle, can be an solution, however more engineering is required.
Also, the maintainability of the device have been explored , focussing on the safe attachment of the needle to the probe. An option to attach and detach the needle safely is provided and tested on its feasibility.
A mature, professional and attractive appearance is aimed for the MarginGuide. According to the insights of the test, the proposed design fits to this appearance.
The final stage is called the Deliver phase in which a conceptual design is proposed. For further development of the MarginGuide, it is primarily important to focus on the influences on the Raman measurement and the needle depth determination, which may influence the accuracy of providing the margin. Important factors influencing the accuracy might be the ambient lights in the operation room and the differences in use.