The large intestines, or colon, is the last part of the digestive tract before the rectum. Colorectal cancer is one of the main reasons that patients need a colon resection. A colon resection is a surgery in which the malignant part of the colon is removed. After removal of the tumor, the two ends of the colon need to be reattached, also called anastomosed. This is usually done using sutures or staples. One of the most frequently occurring and major complications is that the anastomosis does not heal correctly. This can cause an anastomotic leakage, which means that fecal matter and fluids with bacteria can flow into the otherwise sterile abdominal cavity. This is a serious complication that can even result in death. Therefore, a solution can be to insert a stent to cover the anastomosis from the inside, preventing feces and fluids from entering the abdominal cavity. Such a stent was developed at the department of Surgery of the Erasmus MC. This thesis focuses on the redesign of this stent to cover an anastomosis. Two main problems with the stent were stent migration due to insufficient friction between the stent and the colonic wall, and intestinal blockage due to the presence of the stent. Preliminary research and a literature study showed that the addition of barbs to the stent could increase friction with the colonic wall. Optimal barb dimensions were researched on fresh colon specimens in an experimental setup. Ideal barb parameters were a height of 1.5 mm, diameter of 1.0 mm, an angle of 30 degrees, with a distribution of 3 barbs per cm2. In addition, the ideal stent diameter was explored in an experiment with fresh colon specimens. The stent should expand the colon with 50-60%. To safely insert and extract a stent with barbs in the colon, a patent search was executed to explore the possibilities of barb and colon protection. A stent with a reducible diameter and a tubular protection structure were identified as the most promising methods to safely insert a barbed stent. The second problem of intestinal blockage was analyzed and causes of intestinal blockage were identified. Minimizing the frontal contact surface at the proximal end of the stent was assumed to be the most important factor to reduce intestinal blockage. A minimal frontal contact surface also reduces the force that feces exerts on the stent, thus reducing the chance of stent migration. The previously mentioned experiments and analysis formed the basis of a list of design requirements for a new prototype stent. The requirements were divided into five categories; fixation, dimensions, materials, delivery method and performance. After analyzing different manufacturing processes and available materials, two concepts were designed and produced. One concept was chosen after careful considerations of both options. The final prototype consisted of a stent with barbs that was 3D printed. This design was validated on the set of requirements that were set up earlier. The material of the stent is both flexible and stiff. For insertion and extraction of the stent, the diameter can be reduced by longitudinal inward folding, while the stent forms a rigid tube while in a deployed state. The barbs are stiff and strong and can withstand the force that would move the stent. The frontal contact surface of the stent was reduced by more than 18 times compared to the old prototype, to reduce the influence on intestinal blockage. The stent is surrounded by a sheet to protect the barbs and prevent tissue damage during insertion. A validation experiment showed that the stent was improved in fixation compared to the old prototype. Therefore, based on the research executed in this thesis, the final prototype should theoretically migrate less and cause less blockage. However, an ex-vivo experiment should validate the fixation force of the new prototype, and in-vivo experiments on pigs should determine if the prototype actually does not migrate and actually does not cause intestinal blockage.

Gastroschisis, a congenital abdominal wall defect located to the right of the intact umbilical cord (UC), results in the herniation of fetal abdominal organs into the amniotic cavity without a protective membrane covering these structures. Complex gastroschisis (CG), comprising approximately 10% of cases, is associated with significantly higher morbidity and mortality rates compared to simple gastroschisis. Fetoscopic repair of CG offers the potential to improve gastrointestinal health at birth, but thus far, no procedure has been successfully demonstrated as safe and feasible. Therefore, the goal of this graduation project was to provide a proof of principle for a novel dedicated method that enables the swift closure of the abdominal wall defect during a fetoscopic repair procedure for CG. The development of this method began with an analysis of the clinical context, including the characteristics of the abdominal wall defect, the adjacent umbilical cord and vessels, and the fetoscopic surgical setup, which provided a clear design direction. After generating various concept solutions, the key concept — a silicone ring with membrane — was selected using the Harris Profile methodology. This concept was designed for insertion into the fetal abdominal cavity, with the membrane effectively covering the opening of the defect. Eight configurations of the silicone ring with a membrane were then prototyped through injection molding of liquid silicone rubber in a 3D-printed mold. The rings varied in shape (round or rusk), diam- eter (20 mm and 30 mm), and stiffness (shore hardness A25 and A40). Additionally, a validation model simulating a 24-week-old fetus with CG was developed with input from medical experts. The validation experiments demonstrated that the silicone ring with a membrane securely remained in place, effectively closing the abdominal wall defect under intra-abdominal pressure conditions ranging from 0 to 40 mmHg. These experiments, conducted using the validation model, simulated conditions during and immediately after fetal intervention in a 24-week-old fetus with CG following intestinal repositioning. These experiments provided proof of principle for the silicone ring with membrane as a novel method that enables the swift closure of the abdominal wall defect in CG during a fetoscopic repair procedure. Notably, round-shaped rings were favored, and larger diameters allowed for coverage of larger defects. However, it’s noteworthy that the 20 mm round ring effectively covered an oval-shaped defect measuring 13.5 × 12.7 mm, aligning with the reported mean defect size in CG. Furthermore, the experiments demonstrated the feasibility of introducing the rings through a 12 Fr (20 mm rings) or 14 Fr (30 mm rings) surgical port, aligning with the preferred surgical setup. Future research is required to clinically investigate the defect diameter in CG and optimize the silicone ring with membrane’s design. Additionally, enhancing the validation model to serve dual purposes as both a validation and training model will facilitate user tests. Moreover, developing an instrument for introducing the ring into the uterus and refining the surgical technique for precise ring positioning will be essential steps toward the clinical application of this innovative approach.

This thesis concerns the design process of the mechanical excision mechanism of a minimally invasive sentinel lymph node biopsy medical device. The design is tested, validated and improved using force tests, data analyses, proof-of-principal tests, calculations and finite element method models. The conclusion of these analyses is that the mechanism works and that first promising steps towards realising a minimally invasive sentinel lymph node biopsy medical device have been taken.

In up to 30% of hernia patients revision surgery is needed due to infection, pain and defect recurrence. The role that abdominal wall tension plays in this is incontrovertible: most repair techniques in herniorrhaphy aim to reduce tension at the aponeurotic edge, as excess tension is directly related with local ischemia and recurrence of the hernia. Currently, fascial tension is subjectively observed by the surgeon and rarely quantified intra­-operatively. The choice of procedure is based on pre­operative characteristics of the defect, surgeon experience and preference, which can be highly variable. Research shows that an objective assessment of fascial tension can be a feasible adjunct to surgical decision making. Therefore, this thesis provides a proof of principle for MINT: minimally invasive tensiometry. MINT is an add­on tool for existing laparoscopic instruments, which enables an objective assessment of abdominal wall tension by the use of a linear spring. Universal applicability has been evaluated and confirmed in this research. MINT is fabricated using carbon fibre reinforced PA­12 (”Onyx”) at the TU Delft. The device’s safety and effectivity have been validated using several experiments and sterilisation test runs. MINT provides accurate and consistent results in Newton without further calibration. Forces up to 60N can be quantified, with an accuracy of 5.5+/­2%, expressed in Mean Absolute Percentage Error (MAPE). Results show that ”Onyx” and the silicon used can be sterilised using an autoclave at least five times. Moreover, its ease of use and functionality have been assessed in a clinical setting using an embalmed cadaver. Further testing will have to be done to substantiate the results from this research through a larger study. In addition, redesign will have to take place to decrease part count and further improve assembly of the device. The findings of this thesis provide a first step in the implementation of fascial tension measurements for intra­-operative decision making during laparoscopic surgery.

Liver cancer causes 700.000 deaths annually. To assess new devices and pre-clinical procedures for treatment, a safe test environment can be provided by a phantom. Phantoms act as a surrogate for certain physical properties of tissue. The purpose of this study is to design, construct and evaluate an anthropomorphic liver phantom, which simulates respiratory motion and inhibits similar needle-tissue interaction for ultrasoundguided needle interventions. The liver model and surroundings are made from water-based solution with polyvinylalcohol (PVA). The liver model and surroundings are made of 6%m, 4%m PVA with 2 and 3 freeze thaw cycles, respectively. The rigid structures, i.e. vertebrae and ribs, are made of a flexible polymer. Threedimensional printing technique is employed to create molds for the anthropomorphic structures in terms of organ shape. Detailed steps for phantom construction and choice of phantom ingredients and construction recipe are reported. The actuation is provided by a linear actuator, which is adjustable in stroke length, frequency and direction. Preliminary results of the reproduced motion in the liver model are 20.7, 10.8 and 6.7 mm in CC, AP and LR direction, respectively. Further, the phantom allows both subcostal and intercostal ultrasound needle guidance. The liver model is designed to simulate diseased tissue. From Fibroscan measurements, the livermodel is characterizedwith an elastic modulus of 24.0(±8.0) kPa. Further, the liver model shows median higher axial needle friction forces (0.0374 N/mm) compared to healthy liver tissue (0.01108 N/mm). Furthermore, tactile feedback on the liver model is obtained from a liver surgeon, dr. W. Polak, whom graded the liver model with fibrosis scale 2. Based on the Fibroscan results, increased needle friction forces and tactile feedback, the liver model can be classified as cirrhotic. Additionally, the prototype is assessed by head of the section interventional radiology at the Erasmus MC, dr. A. Moelker. The doctor was able to perform ultrasound-guided needle insertion. Concluding, that a working prototype, which simulates respiratory motion and inhibits similar tissue-needle interaction as human tissue for ultrasound-guided needle interventions, is created.

The goal of this study was to design a maternal phantom model specialized for experiments in which the stresses in the amniotic sac can be determined during fetoscopic procedures. These stresses caused by surgical procedures are believed to be the leading cause of post surgical pre-birth. Measuring these stresses indicates the quality of fetoscopic instruments and surgical procedures. Founded with literature and experiments with amniotic tissue, the requirements for the design of the phantom model were formulated. With these requirements as a framework a design was made which was validated by medical specialists. Measuring the stresses in the amniotic sac failed, therefore measuring the translations of the amniotic tissue was used as a measure of trauma. This proved a success as medical specialists were positive about the design of the phantom model. The findings in this study support the idea that there is a need for a maternal phantom model for the development of fetoscopic procedures. Measuring the translations of the instruments through the amniotic sac is a successful method for indicating trauma. The resulting design showed potential as a training tool as well. The developed phantom model is a successful first step in making a maternal phantom model to contribute to the quality of fetoscopic procedures.

Aortic stenosis is one of the most serious heart valve diseases and is the result of calcification of the aortic valve leaflets. This calcification is irreversible and affect the functionality of the heart valves. The only treatment is an aortic valve replacement. The trend in heart valve replacement is moving from open heart surgery towards minimally invasive techniques where a heart valve prosthesis is placed over the native aortic valve, called the TAVI procedure. A crimped stent that contains a heart valve prosthesis is pushed upwards through the femoral access route with a delivery catheter. This prosthesis is placed in the aortic annulus and wedged over the native valve. The positioning of the heart valve prosthesis is important for the success of the procedure and durability of the prosthesis. A coaxial placement to the aortic annulus in the center of the aorta lumen is the target during this positioning of the prosthesis. The Medtronics and Edwards delivery systems, that are currently used, only have the possibility to be steered with a maximum of 1 rotation, providing an alignment with the aortic annulus in the frontal plane of the body. The rotation to provide the alignment in the sagittal plane is lacking. This report will focus on the question if extra steerability of the delivery system will provide a better positioning of the tip of the delivery system, which in the end, will position the heart valve prosthesis. The Edwards delivery system will be reverse engineered to look at the current mechanisms that are used to provide the rotation in the frontal plane. Subsequently, two experiments are performed to select the best configuration for the modification on the tip of the delivery system. Ultimately, the designed prototype will be validated with two tests to answer the research question if the extra steerability will provide a better positioning. The prototype is validated by comparing the positioning of the Medtronics and Edwards delivery system with the prototype during an experiment where the three systems have to be maneuvered to a predefined position in an aorta model of glass. This predefined position represents the center of the aorta lumen in a coaxial orientation. Two rotations and the xyz-coordinations of the tip will be measured by an Aurora NDI system and the results will be compared. It showed that the prototype provided a bigger reach within the aorta lumen and a had a bigger domain of angles in which the tip could be orientated than the prototype. Moreover, the prototype provided a better alignment in the sagittal and frontal plane with regards to the reference point. The research only focused on the positioning of the tip and didn’t take the deployment of the heart valve prosthesis into account. Further development of the prototype is needed to make it useful for the TAVI procedure. In addition, more research is needed to validate the prototype in a dynamic environment that represents the reality with blood flow and more tortuosity in the access route. Nevertheless, the prototype look promising to be used for the perfect positioning of the heart valve prosthesis which will have a positive effect on the durability and functionality of the prosthesis.

Summary Introduction The increasing use of cardiac catheterisation procedures has raised concerns about occupational radiation exposure and its associated health risks for clinicians. Radiation exposure can lead to deterministic and stochastic effects, including cataract and various cancers. To minimise these risks, the ALARA (As Low As Reasonably Achievable) principle must be followed in the clinical setting by applying the available measures. Radiation protection consists of passive and active measures. Passive protection includes architectural shielding, stationary shielding, and personal protective equipment, while active protection focuses on minimising radiation during interventions, employing adjustable lead screens, modifying imaging techniques and provide feedback to improve the usage of these measures. However, current methods for measuring and providing feedback on radiation exposure are insufficient. The primary goal of this research is to find a comprehensive and improved approach to guidance and implementation of protective measures, to ensure the safety and well-being of healthcare workers who face radiation exposure in their daily practice. An integral component of achieving this goal is to create a model that calculates radiation exposure for clinicians in the cathlab with the use of a lead screen. This research aims to determine the feasibility of using dose rate data from measurements without a lead screen to estimate the dose rate in an environment where a lead screen is employed. Moreover, potential methods for communicating dose rate data to clinicians during a procedure will be explored, aiming to increase their awareness of radiation exposure and encourage the adoption of appropriate protective measures without distracting them from the procedure itself. Method Data collection is necessary to construct a model that can predict the radiation scattering. Measurements in the catheterisation laboratory were performed by placing Philips DoseAware Detectors (PDDs) at various locations and heights. Combinations of fluoroscopy or acquisition mode, anteroposterior (AP) view or a 40° tilted view of the C- arm, and the presence or absence of a lead screen, resulted in eight different setups, with each 168 measurements. In the programming process careful consideration has been given to the ease of refining and improving the model afterwards. Three potential source options for the radiation were considered: the centre of the phantom, a point where 50% of the scattering has occurred, and a 3D representation of the entire phantom. The modelled lead screen together with the source was used to create an attenuation grid, which will be used for the estimation of the effect of the lead screen. The adequacy of the estimated dose rates with the lead screen was evaluated using boxplots and counting the number of correctly estimated points. Then, the data was interpolated using Kriging. The interpolated data was visualised, and the radiation doses for the assistant and cardiologist were calculated at the chest and head levels. The exposure calculation was performed for three lead screen positions and a scenario without the lead screen. The placements considered were close to the clinician, close to the phantom, and at the edge of the phantom. To explore radiation feedback preferences, a literature review and a questionnaire for interventional cardiologists were conducted. Results Measurements were taken for eight different setups, each with 168 measurements, including the combinations of fluoroscopy or acquisition mode, anteroposterior (AP) view or a 40° tilted view of the C-arm, and the presence or absence of a lead screen. The interpolated data revealed that the dose rate is higher when the acquisition mode is used, and radiation levels are higher when the C-arm is rotated. Three different source types were incorporated into the measurements, and the accuracy of the estimations was evaluated based on whether they were within a deviation of 0.1 mSv/h from the actual measurements. The 3D source was found to be the most accurate representation of the source in the model. Visualisation of inaccurately estimated values showed that the model overestimated the amount of radiation blocked in certain cases. The radiation exposure for clinicians increased as the lead shield was positioned closer to the radiation source. A questionnaire was conducted with five interventional cardiologists to investigate their radiation safety practices. The results indicated that radiation safety is deemed important, with an average score of 8/10. The lead screen is an essential shielding component, but its placement varies, and there is uncertainty regarding its optimal positioning. Monthly reports on total radiation dose exposure were provided. The clinicians hardly paid attention to this information, as they believed that any potential harm had already occurred. The highest-rated techniques were advice on optimal lead screen position (displayed on the lead screen) and a visualisation using augmented reality that displays the scatter pattern on the monitor. Discussion and Conclusion This study addresses radiation safety in interventional cardiology by exploring protective measures. A preliminary model was developed to predict radiation exposure based on the location of the lead screen enabling the computation of the radiation dose received by clinicians during a procedure. This dose rate model helps to visualise the impact of lead screen positioning on radiation exposure, which can aid in real-time decision-making during procedures. The model also revealed that placing the lead screen closer to the clinician, rather than closer to the source, could potentially enhance radiation attenuation by a factor of 6.2. This results in a possible dose reduction up to 32.5 times. The most preferred option by the interventional cardiologists was to display the suggestion of the optimal position of the lead screen directly on the shield. A potential addition to the feedback system could be an augmented reality (AR) visualisation of the radiation effect on the monitor, clearly showing safe areas for personnel. The precise feedback mechanism should be piloted and refined to ensure seamless integration into clinical practice without distracting the clinician from the procedure itself. Understanding the limitations of the measurements and the model is crucial for optimising its application in practice and the improve the reliability. The accuracy of measurements obtained with the DoseAware badges, while sufficient for this project, could be improved by using more accurate instruments. The phantom used in the study does not accurately represent real patients, and future research should involve patient- specific inputs and more realistic phantoms. One of the key future objectives include collecting more data in different settings and positions of the C-arm, as well as investigating different positions and orientations of the ceiling-mounted lead screen. The model itself has limitations in its representation of the scattering source and interpolation methods. To improve the model, researchers should account for other sources of scatter, and assess alternative interpolation techniques using more powerful computing resources. Moreover, to calculate the received radiation dose, the model should consider the entire body, accounting for the protection provided by a lead apron and the concept of effective radiation dose. Accomplishing these objectives will allow the model to play an important role in enhancing cathlab radiation safety, benefiting the health and safety of clinicians.

The operating rooms (OR) in hospitals is a complex system, with a high number of innovations every year. Therefore the healthcare professionals (HCPs) are required to choose between the several aspects and innovations for the OR. Decision-making requires a mutual vision (Littlejohn et al., 2017) and should be based on evidence (Turner et al., 2017). To improve the well-informed decision-making, the main research question is: “How can a decision-support tool for optimisation in the operating room help a healthcare professional to select the objectives and the assessment criteria for performance optimisation of the operating room and the optimisation impact?”. The evidence for the tool consists of the 223 relations between the objectives and the assessment criteria (metrics) and 253 causalities of metrics that express the impact. There is a high heterogeneous perspective on the objectives of the optimisation of the performance of the OR and the criteria of assessing the quantification of (the optimisation of) the OR performance, which makes it harder to create a mutual vision on the OR performance. To achieve a mutual vision, a holistic view and consider all the perspectives, including the impact of optimisations, the HCPs should all share their perspectives on the objectives and the situation should be considered in its whole (Leinonen et al., 2008; Littlejohn et al., 2017). Therefore, the decision-making process could benefit of a decision-support tool. In this study a new tool is developed, namely the Performance Operating Room Counselling (PORC-)tool. This tool provides a holistic view of the OR performance (optimisation), by displaying evidence of the relations between objectives and metrics and the causalities. It also supports a conversation, which could lead to a mutual vision (Littlejohn et al., 2017). The tool is based on the concepts flowchart, matrix table and Microsoft Excel, for respectively the roadmap, the information display and the running-programme. The PORC-tool consists of an Excel file, a brochure and a manual with a more elaborated version of the functionality and the steps. The PORC-tool provides a clear and structural overview with evidence, to gather information more easily, provides multiple perspectives on the OR performance and supports to gather more insight into the OR organisation and goals before the decision-making of the HCP. The PORC-tool should be validated in practice and the functionality should be approved by HCPs. In the future, the tool can also be extended on perspectives, field of interest, aesthetics and functionality. To conclude, the answer to the main research question is that the HCPs should be facilitated to consider the whole complex system in their decision-making process, and support the decision-making based on evidence and with a mutual vision.

Technological developments in the medical world introduce a shift in responsibilities of the surgical team members which might result in waste of talent and skills. The latter might result in disengagement and decreased productivity and thus in illness-related absenteeism. The people pillar of sustainability aims to create a healthy workplace and thus to manage illness-related absenteeism. The objective of this research was to optimise the responsibilities of the surgical team members in minimally invasive surgery (MIS) in order to achieve a balanced and sustainable employability of the surgical team to counteract waste of talent and skills. Empirical data was collected in two different steps. In the first place, an overview of the surgical phases during the MIS procedure and an overview of the tasks performed by the perioperative nurses were made. In the second place, two different methods were used to obtain data. First, seven video recordings of a laparoscopic gynaecological procedure were analysed to obtain the distribution of the responsibilities and the percentage of (technical) tasks for each phase and the entire MIS procedure. Second, interviews with fourteen perioperative nurses were conducted to map the peak moments of a MIS procedure and to evaluate the impact of the technological developments on the nurse's workload. As a result, a fluctuation of the total duration of all tasks during the procedure was shown. A percentage higher than 70% was measured in the start phase. The perioperative nurses experienced low peak moments during 66% of the entire surgical procedure. A high impact of the technological developments was experienced by the nurses. The physical activity for MIS and robot-assisted surgery (RAS) was lower than a conventional open procedure (OS). The total duration of the technical tasks was highest in the second phase of the MIS procedure. The nurses indicated that this phase took longer compared to the same phase in OS procedures because of the amount of equipment that has to be connected. In conclusion, an unbalanced employability was recognised during MIS and technological developments had a high impact on the activities of the perioperative nurses. This research has several recommendations. First, a more sustainable employability will be achieved when two perioperative nurses will be scheduled for three surgical procedures during 66% of the MIS procedure. Second, deployment of a technical perioperative nurse will decrease the amount of workload. Last, by giving the perioperative nurses more responsibilities in MIS, the talent and skills will not be wasted leading to a more balanced employability of the surgical team members.

Massive acetabular bone defects are difficult to treat with the currently available implants. Advances in additive manufacturing create new design possibilities, which allow the production of patient specific implants. These endless possibilities will enable to tune the mechanical properties of porous implants and to distribute the loads in such a way that it mimics the natural load distribution. This technique will therefore be used in the design of a new type of implant, which is a deformable acetabular implant that will fully fit in a massive acetabular defect after plastic deformation. In this way, all remaining bone will be loaded, and the physiological load distribution will be restored to maximally reduce stress shielding and to prevent further loss of bone stock. To design this new implant, more information is required on the mechanical properties of the titanium porous structures. Therefore, the aim of this study is to examine the mechanical properties and deformation behaviour of highly porous pure titanium (grade 1) structures. The diamond unit cell was used to design three types of structures with different porosities (> 95%). A static compression test was performed on cylindrical samples. In addition, push-in and pull-out tests were performed on hemispherical shaped samples. The samples were compressed into specially designed moulds, which represent the acetabulum with defects, to test how these structures deform according to their surrounding shape. Micro-CT images were made during and after the test to analyse the deformation. The cylindrical samples continuously deformed during compression and large plastic strains were measured (> 57%). The hemispherical samples deformed conform the surrounding mould and even penetrated into the holes. The push-in and pull-out forces are positively correlated, and these forces are lower for more porous structures. The micro-CT scans show that all unit cells within the structure do not equally deform under compression, but show a gradual, layer-by-layer deformation. This study is a first step towards the design of a deformable implant. The results are quite promising and can function as a basis for future work.

Brain, outside the body, will decay quickly, causing ex vivo studies to be difficult. Having a phantom model has a great beneficial value for numerous reasons. Phantoms are, among others, used in research centres, to validate new equipment, to develop biomechanical models or to test new treatment methods. They are representations of organs or tissues made from tissues that mimicking the desired properties of the organ. This thesis research is performed in collaboration with Philips Healthcare research department. They benefit from having a brain phantom for the development of a new endoscopic tool that incorporates virtual reality images in the view. Existing phantoms are usually expensive and are not meant for destruction by needle interventions or endoscopic interventions, or are a very rough representation of reality. For this study, it was the aim to develop an anthropomorphic brain phantom containing the hollow space of the ventricles of the brain, with the correct mechanical and optical characteristics. From a digital 3D mesh brain, moulds were made to assess different ways to produce a brain phantom with ventricles. From literature, the tissue mimicking material (TMM) PVA was selected to use for the production of the phantom. After evaluation of the different approaches to fabricate a phantom, it was decided to produce the hollow spaces of the ventricles by using 3D printed soluble PVA, to be removed out of the model after casting. This was done by 3D printing a brain mould in which a 3D printed PVA ventricle could be inserted. A solution of 6% PVA as tissue mimicking material was used. After the mould and production principle of the model was finalized, the imaging part was assessed. In order for the phantom to be used in CT imaging, barium sulphate was added to the PVA solution as a contrast enhancing material. Two phantoms were made with 1% and 2% barium sulphate. Finally, to assess the shape and the quality of the ventricles in the phantom, the phantom was scanned with a CT scan at Philips Healthcare in Best, the Netherlands. The CT files were evaluated using RadiAnt and 3D slicer to assess the ventricular shape and position. 3D slicer was also used to segment the ventricle shape out of the designed models to compare with the originally developed ventricle structure. This study functions as a proof of concept for the development of a PVA brain phantom containing ventricles produced with 3D printed soluble PVA. All in all, the overall evaluation of the prototypes have shown to be promising models for the development of a brain phantom using PVA and ‘homemade’ fabrication techniques. The use of 3D printed soluble PVA is a novelty in this field of application. It makes the design easy to develop and easily adjusted to patient-specific cases as personalized models can be made.

Sentinel lymph node biopsy (SLNB) is a procedure that is used to determine the stage of disease of melanoma patients and determine further treatment. However, the morbidities accompanied with this procedure are not negligible (e.g., wound infection, lymphoedema and seroma). With the goal reduce the incidence of morbidities, this thesis investigated the possibility of minimally invasive sentinel lymph node biopsy (MISLNB). Preceding this thesis, a literature study was written by the writer of this thesis to examine whether there was already a possible solution for this problem. This literature study showed that there are no off the shelf available solutions for MISLNB. Therefore, three solution with the reduction of comorbidities and the importance of extit{en bloc} excision at their core were proposed. These solutions were found through literature, patents, and some ingenuity. The solution with the highest probability was selected to develop further. This concept was then subjected to different experiments to determine whether it was viable option for MISLNB. This study also aimed to fill some of the missing data on the material behaviour of lymph nodes (LN), specifically stress-strain behaviour under compression. By using a set of requirements one solution was selected to be the most viable given the available information. This solution was called the Pull-and-Harvest method. This concept uses a vacuum to grip the sentinel lymph node (SLN) and stash it in a tube, hereafter a snare would cut the lymph ducts and blood vessels. This concept scored well mainly due to the low risk of damaging SLN and its simplicity. The next step was to determine whether this concept was a feasible solution to MISLNB. The problem was divided into three subproblems to estimate this feasibility. The first being the force required to separate the SLN from its surrounding tissue. Since no data on this subject was available a simplified model was created to estimate this value based on the stretch of lymph ducts. The second part of this problem was, determining the force required to stash the SLN inside the tubular volume. Finally, the maximal force of two silicon suction cups was determined. From these experiments several conclusions could be drawn: the conical silicon suction cups used in this study are very inefficient (10%) efficiency) for gripping LNs, these suction cups will stash the LNs but probably not with the additional estimated adherence force and the risk of damaging the LN using a vacuum seems to be low. Based on these observations during these experiments possible ways of were suggested and could make the Pull-and-Harvest a viable procedure. Lastly stress-strain behaviour of LNs could be described using an exponential relationship. This thesis outlines the problem of MISLNB and highlights the areas of interest for further research. However, there is more research and development needed to find a definitive solution for MISLNB.

Augmented reality (AR) promises to be a valuable tool for anatomical education since any given anatomical site can be studied dynamically in three dimensions (3D). Yet, it has not been used with case-based learning in medical education despite the latter's demonstrated benefits. This research, thus, investigates the potential benefit of 3D holographic animated surgeries on functional anatomical knowledge acquisition. We developed four educational AR applications comparing two cases with and without the presence of a surgical animation. Based on this, a randomized crossover trial was conducted among second year medicine students. All subjects (n = 10) underwent a spatial visualization assessment, followed by a learning session and an anatomical knowledge test for both patient cases. The presence of a surgical animation did not lead to a significant difference in anatomical test scores. In addition, no correlation (τ = -0.092, p = 0.78) was detected between the effect of surgical animations and spatial visualization abilities. However, these results are based on non-parametric statistics, as normality could not be assumed. Further research with samples representative for the population, conducting both qualitative and quantitative analysis using verified outcome measures and parametric statistics is required to draw accurate conclusions.

Treatment of liver diseases is often done by means of interventional radiology and thereby needles are widely used. These needles are under constant development and therefore needle-tissue interaction data are necessary. The goal of this study is to provide data on needle forces during puncturing of liver blood vessels. These data can be used to mimic blood vessels in a polyvinyl alcohol (PVA) liver phantom, intended for needle development and training purposes. Needle insertion experiments were done on human livers, by puncturing portal veins, hepatic veins, hepatic arteries and liver tissue. The resulting force data show that peak forces are higher during puncturing of liver veins (median=2.20 N, interquartile range=1.46 N to 3.67 N) than during puncturing of liver tissue (median=0.38 N, interquartile range=0.31 N to 0.51 N). The force data were used to find a blood vessel mimicking material. Silicone, with the addition of a mesh fabric, was found to mimic the peak forces of liver veins during needle insertion. A silicone blood vessel was created with use of a 3D-printed blood vessel structure made of water-soluble PVA. The addition of the mesh fabric, furthermore ensures proper bonding between the silicone blood vessel and the PVA liver tissue. The methods described in this study can be used to implant artificial veins in a PVA liver phantom.

In hospitals, the duration of surgical procedures vary even when the same procedure is performed. Surgical end-time of the procedure is currently predicted using historical data about similar procedures, the procedure time and sometimes an indication of the operating surgeon is also taken into account. After the start of the procedure, there is no documented communication between the operating room (OR) planner and the surgical team inside the OR. When the procedure is finished, a nurse has to call to inform that the next patient can be prepared for surgery. If an update of the progress of the procedure is needed, there has to be communication between the staff outside the OR and the surgical team inside the OR. To lower the workload and reduce the distractions for the surgical staff, the communication needs to be automated. This can be done by developing a support system that communicates the progress of the procedure in the OR automatically to the staff outside the OR without the need for human interaction. In this study, automatically communicating the progress of the procedure is realized by introducing a radio frequency identification (RFID) system that tracks the instruments during the procedure. With this information, the different phases of the procedure can be recognized and this will aid in the communication and the prediction of the surgical end-time. To be able to detect the instruments with an RFID system, a minimal reading distance is required. In this study, different approaches are tested to increase the maximal reading distance of RFID ’on-metal’ tags to ensure the range is far enough for the technique to be used during a totally extraperitoneal (TEP) procedure in the OR. The desired reading distance is 50 cm. The study started with a set of instruments with RFID tags attached to them. In a pilot study, the reading distances were measured and resulted in an average reading distance from the antenna which was too low. Using a larger antenna resulted in a slightly higher average reading distance, but still not high enough. Raising the power of the antenna could be increasing the reading distance. The tests are, however, already performed with the maximally allowed 2 W. To determine the problem with the reading distance, the different properties of the attachment of the RFID tag to the instruments are investigated. The influences of the different properties are tested and the results are combined to make a final design that is supposed to have a higher maximal reading distance than the instruments in the pilot study. The final design is tested both in the clinical lab at the TU Delft and in an operating room at the Reinier de Graaf hospital in Voorburg. The reading distances of the tags on the final design were improved and sufficient for the use in a TEP procedure. Finally, the tags are attached to three instruments with a temporary connection to measure the reading distances with the influences of the instruments. The results of this test show that the desired reading distances can be accomplished with RFID technology.

Introduction. To prevent burns from scar formation and contraction, the use of splinting therapy in the early phase of wound healing is considered as an effective non-surgical method. Splinting entails the application of a mechanical load in the opposite direction of the contractile force within the wound, based on the assumption that wound- or scar contraction will be prevented or reduced. However, clinical research provides conflicting evidence on its effectiveness and optimal treatment method. Therefore, the aim of this study was to design an in vitro model to investigate the mechanoresponsive cellular effects of stress on specifically Human Eschar Fibroblasts and their extracellular matrix, in order to confirm or disprove effects of burn splinting. Methods. The two major players of the burn wound model include (1) the fibroblasts, and (2) the novel extracellular matrix they produce. Outcome measures were chosen that directly relate to matrix organization, fibroblast functioning and matrix functioning. Three chronological sub-goals were defined to achieve the goal of designing a burn wound splinting model: (1) Formulating a suitable mechanical stress protocol; (2) Select a system that enables the selected mechanical stress of extensible substrates that facilitate the growth of fibroblasts and their derived extracellular matrix; (3) Create and optimize conditions to culture fibroblasts on an extensible substrate. To successfully reach these goals, the current literature on this subject was evaluated and comparative experiments were executed. Feasibility of the model was tested in a pilot study. Results. The MCB1 stretching apparatus was provided by Association of Dutch Burn Centre as a suitable device, which was modified to fulfill all predefined requirements. Human Eschar fibroblasts and dermal fibroblasts were cultured on custom made silicone culture wells. Cross-linked gelatin-A coating and vitamin C-supplemented culture medium were selected for optimal cell culturing results. A clinically relevant stretching regimen was chosen, given the paucity of available evidence in literature. A pilot study to test the feasibility of the model indicated that both dynamic and static stretching of eschar fibroblasts show a trend towards thicker, denser collagen matrices compared to unstretched conditions. These collagen fibers also showed a greater degree of alignment. However, no definitive conclusions can be drawn since sample size is limited. Conclusion. The model presented in this work constitutes a practical framework to test mechanotransducive processes in burn scars on a cellular and molecular level. A pilot study using this model showed excellent feasibility

This thesis investigates clinical phase recognition for cardiac catheterization purposes, focusing on coronary angiography (CAG) procedures, in the context of an increasing annual prevalence of coronary artery disease. It applies machine learning to analyze C-arm logs and video recordings, aiming to improve procedural efficiency by recognizing procedural phases. Key findings include a baseline model with 45% accuracy; an 80.73% accurate C-arm model, including predictions only for operative phases; a 63.8% accurate object detection model, effective in initial and final phases but less so in operational stages; a combined data model with 79.46% accuracy, showing enhanced performance; and a reduced granularity model achieving 88.23% accuracy, highlighting a balance between granularity and performance. The combined model promises effective CAG phase recognition, especially with reduced granularity, offering comprehensive coverage and improved accuracy. However, it faces challenges in predicting specific phases accurately. The study recognizes limitations like the random forest model's non-temporal nature and potential information loss from object detection. Future research should expand datasets, explore temporal data models, and optimize the balance between granularity and performance for clinical applicability. In conclusion, the thesis contributes to SPR in cardiac catheterization labs, particularly in CAG, demonstrating the potential of machine learning models using C-arm and video data for phase recognition, which could enhance operational efficiency and patient care quality in cardiovascular interventions. Further research is needed to refine these models for clinical use.