Introduction - Post Partum Heamorrhage (PPH) is a leading cause of maternal morbidity and mortality worldwide, necessitating immediate and effective intervention. Manual external aortic compression is a recognized technique for temporarily managing PPH, but it poses challenges such as physical strain on healthcare providers and difficulty maintaining compression during patient transport. This graduation project aimed to develop a device capable of managing PPH through external aortic compression, providing continuous and adjustable pressure on the abdominal wall.

Method - Through the mechanical engineering design process, including problem definition, requirement analysis, conceptualization, and selection, CAD designs were developed for two device modules. When combined, these modules form one cohesive device. Subsequently, two functional prototypes were made for each device module and subjected to three studies: an evaluation on healthy volunteers, a user study with healthcare personnel, and mechanical testing to assess structural integrity under load.

Results - The comfort and fit study with healthy volunteers indicated positive assessments for both belt prototypes. The user study revealed that the Semi-Rigid Belt combined with a Tooth-lock module, outperformed the Vacuum Belt with a Scissor Press module, in achieving successful aortic compression on a manikin. Mechanical testing demonstrated that all prototypes maintained structural integrity under the maximum expected operational loads, although some design enhancements were identified as necessary.

Conclusion - This study successfully developed and evaluated prototypes for an external aortic compression device aimed at managing PPH. While initial results are promising, further research and development are required to enhance the mechanical design and improve and indicate the device’s stability and effectiveness.

Leprosy is a neglected tropical disease affecting people worldwide. Left untreated or starting therapy too late, the infection can cause permanent damage to the nerves, skin, eyes, and limbs of patients. While current standard diagnostic techniques generally detect the disease once symptoms have manifested, infrared thermography presents a potential tool for the early detection of leprosy-related neuropathy. A research initiative has been established to explore whether autonomic nerve impairment in the hands can be identified using infrared thermography, necessitating a new method for temperature evaluation. This work discusses the development of a semi-automatic temperature analysis method for twelve regions of interest on the hands. The approach utilises real-time landmark tracking based on an existing machine-learning model, adapted to the context of the application. After applying a cold impulse and recording the response with an infrared camera, the rewarming temperature and recovery values are determined within the regions. Results presented in this report indicate no significant improvement compared to the existing manual method. The success of the model outcomes highly depends on the accuracy of the machine-learning-based hand landmark detection, resulting in insufficiently reliable outcomes. The underlying explanations and the potential for future improvements are further discussed in this thesis, considering the evident potential and benefits of the automated approach.

The human eye is a very delicate yet highly intricate organ, and treatments such as cataract surgery call for meticulous precision. Ophthalmologists hone their skills over years of practice, which they initially acquired during their studies in medical schools. Basic skills such as globe fixation and capsulorhexis training have a very steep learning curve as they are fundamental, albeit very challenging from the get-go. There is a lack of training simulators that can combine both surgical techniques as effectively and economically as animal eye setups. In this respect, the present research work aims at designing a cataract surgery eye phantom for capsulorhexis and globe fixation, which can replicate the movement of the eyeball in the orbit coupled with the inherent passive stiffness. The project culminates in the design of a 2-degree-of-freedom anterior human eye phantom with anatomically similar features of the human eye needed for training the aforementioned surgical steps. A significant part of the prototype structure is 3D printed using Draft resin V2 on the Formlabs Form 3+ printer to create minute yet almost anatomically impeccable components. Mechanical analyses were performed to tune the passive stiffness of the compliant mechanisms, and materials such as PlatSil Gel-00, hydrogel, and eggshell membrane were chosen and utilized to replicate the interactions between the tools and various tissues in the human eye. Clinical evaluations were conducted by a surgeon performing capsulorhexis on the prototype in a wet lab environment and several validation tests by an academic trainer for the suitability and practicality of the prototype. In that context, the present research serves as the first step toward creating innovative designs for training phantoms in the field of eye surgery.

This thesis proposes a method of detecting autonomic neuropathy in low-income countries using an infrared camera. Access to healthcare is often limited in low-income countries delaying the detection of neuropathy. If neuropathy can be detected in the earliest stage, often the autonomic state, damage to motor and sensory nerves can be prevented. To develop the method for detecting autonomic neuropathy, first the autonomic system was researched, followed by looking into the effects of neuropathy on the autonomic system to discover what physical properties might be measured with the detection device.
Four affected physical properties were determined through literature research: blood flow, blood pressure, skin resistance, and skin temperature. Of these properties, skin temperature was found to be the most promising based on a literature study, as it seemed to be both easily measurable and relatively independent of other bodily functions. Then the constraints of healthcare in low-income countries were examined and devices that work within these constraints were identified. Of these, the infrared camera showed the most promise, because of its ease of use and cost to accuracy ratio.
A single-subject study was performed to test the restorative capacity of the autonomous system by deliberately changing the temperature of the hand with a heating and cooling agent. Four locations were used on both hands, and both palmar and dorsal side of the hand, using different doses of the agents. The temperature change of the skin was measured using an InfraRed (IR) camera.
A large variation in results was found, but the results did show some evidence for structural differences in the temperature normalization between the affected and unaffected hand. The palmar side shows a stronger reaction than the dorsal side. The cooling agent seems to be more effective, but there are some caveats attached to its use. An interesting observation is that the most noticeable difference between left and right was measured in an area of low circulation. This gives some indication that this area has the most difficulty with returning to the neutral state.
Conclusion: This research shows that skin temperature variation as a result of applying heating or cooling agents to the skin can be measured using an infrared camera, suggesting that minor variations in skin temperature as a result of neuropathy can also be measured, further research with more test subjects should be done.

The availability of laparoscopy in low-income settings has been limited based on the requirements that have to be met to perform this type of abdominal surgery. At the same time, these regions and countries could stand to gain the most from it based on quicker recovery times and a lower chance of infections. Attempts have been made to solve this inaccessibility by minimizing the required components to perform this type of surgery at a substantially lower cost. None of these projects have resulted in a laparoscope that can compete with commercial laparoscopes regarding resolution, image quality, and critical design features such as viewing angle. Based on these shortcomings, this study aims to design a sub-500-dollar modular laparoscope for gas and gasless laparoscopy that adheres to state-of-the-art image quality and design features. The laparoscopes are designed following the 'Roadmap for Design of Surgical Equipment for Safe Surgery Worldwide”. Based on the roadmap requirements regarding the needs of patients, end-users, and stakeholders, were acquired focusing on cost, robustness, and reusability. Following the design process, two intermediate prototypes were developed, which were evaluated based on function and image quality by a laparoscopic surgeon to validate the requirements and receive design feedback. They resulted in a modular laparoscope that connects with USB to a laptop, which shares the image sensor, light source, electronics, and handle between the laparoscope for gas and gasless laparoscopy. The gasless laparoscope employs a flexible chip-on-the-tip design that can be straightened for entry through a trocar and released to set the tip angle at 30 degrees. The gasless laparoscope does not have to comply with the trocar and can enter straight through the abdominal entry point. Resulting in a chip-on-the-tip design, which is statically bent at an angle of 30 degrees. To validate the design, a laparoscopic surgeon evaluated the function and image quality, and additional tests were performed to validate the thermal and reprocessing capability. The study resulted in a modular sub-500-dollar laparoscope for gas and gasless laparoscopy, which shows great potential but requires future work to be certified and production-ready.

This study investigates surgical stainless steels 304, 410, and 420 corrosion susceptibility under manual reprocessing conditions typical of low- and middle-income countries (LMICs). Cleaning protocols using sodium hypochlorite and the enzymatic agent Sanizyme were compared alongside an accelerated Salt Mist Test to explore predictive value for corrosion. Results show that sodium hypochlorite causes rapid corrosion across all steel types. In contrast, Sanizyme significantly delays corrosion onset and reduces the affected surface area, with stainless steel 304 demonstrating the most outstanding resilience. Minor differences between 410 and 420 were observed, with no significant performance distinction.
Including 2-hour rest periods, intended to activate stainless steel’s self-healing properties, did not significantly impact corrosion resistance. Additionally, the Salt Mist Test showed limited correlation with corrosion development observed under manual reprocessing conditions, indicating the need for refined predictive methods. These findings suggest that gentler enzymatic cleaning protocols enhance the longevity of surgical instruments in LMIC contexts, while accelerated corrosion tests may require adjustments to simulate clinical reprocessing better.

Background: Bilateral tubal ligation (BTL) is the most common method of contraception worldwide because it is safe and effective. However, its accessibility remains unequal among women in rural India, in part due to a lack of laparoscopic equipment. Rural hospitals therefore resort to gas insufflation-less laparoscopic surgery (GILLS) because it requires less complex equipment. The pneumoperitoneum is replaced by an abdominal wall lift (AWL) device, but these devices suffer from limitations concerning visibility and working space.
Methods: Initiated by the identified medical needs in rural India, a novel AWL device with an integrated imaging system is designed based on methods from literature and input from local end-users. It is a stainless steel hollow circular hook housing an LED lighting system and a 5 MP camera module. It can be connected to any laptop with a USB-A port. The device substitutes for both the traditional AWL device and currently used laparoscopes. The design is exemplified by a fully functional aluminium prototype used for verification and validation.
Results: The selected camera module is the key technology of this design because it provides state-of-the-art imaging at an unmatched price point. The lighting system used for the prototype does not provide enough light, has an asymmetric illumination distribution, and generates too much heat. A structural strength test showed that the strength of the prototype exceeds the material-adjusted design load by 30%. Furthermore, the prototype is cost-effective, lightweight, compatible with current AWL systems, and has limited waterproofness. User tests with an expert rural surgeon confirmed that this design has the potential to improve surgical outcomes of BTL and other procedures, and can increase access to specialized medical care in rural India.
Conclusions: It is strongly recommended to continue the development of this AWL device. The focus points should be the shape and size of the loop (and related cost-effective production techniques), a new lighting system, and the waterproofness of the device. Collaboration with rural surgeons and local biomedical engineers is crucial for context-driven development and implementation.

As people’s life expectancy increases, more individuals will develop degenerative diseases over their lifetime. Surgeries like spinal fusion can help manage these diseases to improve mobility and alleviate pain in the aging population. During spinal fusion, two or more adjacent vertebrae are connected to stabilize part of the spine. Since it takes several months for the bones to grow together, connecting rods and pedicle screws provide support in the meantime. Inserting these screws into the vertebrae is a delicate procedure that, if not done correctly, could harm nearby nerves and blood vessels. To find the correct screw trajectory, surgeons rely on tactile feedback and their experience, as they cannot see inside the body. To support surgeons and enhance safety, the procedure can be guided by technology. Although surgical navigation systems exist, their high cost is a barrier to widespread use. A simple and affordable alternative is tissue sensing technology, which provides insights into the structure and composition of the tissue being examined. This information helps detect the border of the vertebra during spinal fusion to prevent breaches into surrounding tissue. Even where surgical navigation is available, tissue sensing offers an extra layer of safety, for instance, if the spine has moved during surgery....@en

Ensuring reliable and safe performance of medical devices in healthcare institutions is crucial for the wellbeing of patients. For this, physiological simulators may be used, which provide reference signals to compare against. The usage of physiological simulators, such as ECG simulators, as medical device testers is widely extended in high-income countries. However, their high cost and need for frequent calibration by the manufacturer make their availability and usage in low-resource settings (LRs) unfeasible. Remote healthcare facilities, low- and middle-income countries (LMICs), and hospitals in general would highly benefit from new designs of simulators that can be produced, repaired and maintained locally. Therefore, we present the design of an affordable, portable Arduino UNO-based prototype ECG simulator with the novel feature of visual indicators for self-calibration checks. The ECG simulator was built with affordable and broadly available components and tools, retrieved from an educational electronics workshop. The current prototype can be used to test 3-lead ECG meters. It reproduces a lead II waveform extracted from MIT-BIH database, with 1.3 mV peak-to-peak and 0.1 mV negative offset. Heart rage simulation ranges from 35 to 130 bpm, in steps of 5 bpm. Signal data points defining a desired waveform and heart rate can be uploaded into the simulator via the user-friendly and open-source Arduino software. The simulator could also be modified to generate 10- or 12-leads by upscaling the electronics and adding more storage space. Analog signal generation is based on a pulse-width modulation signal, which is smoothened by a low-pass filter and decreased in amplitude with operational amplifiers, which also add a negative voltage offset. Visual indicators enable simulated frequency and amplitude checks without the need of external tools, while amplitude can be calibrated manually. Additionally, rechargeable batteries facilitate on-site testing of medical equipment. Evaluation of the prototype included performance and functionality tests. HR and amplitude accuracy of the simulated signal were quantified and compared to those from a commercial simulator. Lastly, the performance of the simulator in a real scenario was tested at the Green Pastures Hospital of Pokhara, Nepal. Functionality tests proved the correct detection of the simulated signal by 6 patient monitors of different models, manufacturers and purchase year.

Objective: This work focuses on the feasibility of using Electrical Impedance Spectroscopy (EIS) to differentiate between cancerous and healthy tissues in real-time alongside the GI tract. This is to see whether it is possible to support surgeons when taking biopsies, or to see if it is possible to make biopsies obsolete with EIS. Methods: The study is limited to three tissue types representing the GI tract. These tissues are the esophagus, ileum, and colon tissue. Impedance measurements are taken with a 4-electrode probe on a Hewlett Packard 4192A LF HP Impedance Analyzer. All measurements are taken over a frequency range of 1 kHz to 7 MHz in 300 steps. Seven patients are included: three esophagus, two
leum, and two colon. Forty-eight ex vivo measurements are taken; 32 are on healthy tissue and 16 on cancerous tissue. Almost all measurements are verified by histological assessment (golden standard). In this work, a combination of parameterization with a classification method is made to create a classification strategy. These can be listed as the Cole impedance model, the two-pole Cole impedance model, the two-pole Cole impedance model in combination with a
Constant Phase Element (CPE), and PCA. The Cole impedance models are combined with thresholding, and the PCA is combined with a SVM. Results: The thresholding algorithm is created in combination with the α2 parameter (P < 0.05) from the two-pole Cole impedance model in combination with a CPE. The thresholding value is determined in a LOOCV approach via ROC curves created to search for the threshold that gives the most significant summation of sensitivity and specificity. In the combination of PCA and SVM, the PCA uses three principal components (containing 96.37% of the total variance), and the SVM applies an Radial Basis Function (RBF) kernel. For the 2-pole Cole impedance model with CPE
in combination with thresholding, we find an accuracy 0.5208, sensitivity 0.4375, specificity 0.5625, Positive Predictive Value (PPV) 0.3333, Negative Predictive Value (NPV) 0.6666, and Mathews Correlation Coefficient (MCC) 0.0000. For the PCA in combination with the SVM, we find an accuracy of 0.4167, a sensitivity of 0.0000, specificity of 0.6250, PPV of 0.0000, NPV of 0.5556, and MCC -0.4082. Conclusion: It is concluded that we cannot create an algorithm that either supports surgeons or replaces a biopsy in the GI tract with the current setup. This is highly likely due to the extremely low amount of data that is included to train
the algorithm.

Vulvar cancer has significant implications for women's health and quality of life, emphasizing the need for prompt diagnosis and treatment. Surgical treatment aims to remove both visible and nonvisible malignant cells, incorporating a safety margin beyond the tumour perimeter. However, accurately assessing cancer spread and determining the optimal safety margin size remains challenging. Hyperspectral imaging allows non-invasive identification of vulvar tumour boundaries, capturing both spatial and spectral details of the region of interest. However, tissue type classification in hyperspectral imaging is complex due to the abundance of wavebands and limited training samples. Artificial intelligence (AI) methods show promise for accurate and automated tumour classification in hyperspectral imaging. In this study, four AI models (Support Vector Mechanism, Neural Network, 1D and 3D Convolutional Neural Networks) were trained to classify tumour tissue, skin tissue, and mucosa tissue. Additionally, the study aimed to explore the use of specific explanatory parameters (Tissue Water Index, Near Infrared Perfusion Index, and Tissue Haemoglobin Index) to reduce the spectral dimension, potentially improving acquisition time and interpretability without compromising classification accuracy. The study included 25 patients (mean age 71), with hyperspectral cubes captured from each patient. All cubes contained healthy skin tissue, while 22 cubes included tumour tissue and 10 cubes contained mucosa tissue. All models exhibited comparable performance for tumour detection, with F1 scores ranging between 0.91 and 0.93 and AUC-ROC scores ranging between 0.91 and 0.94. Moreover, the Neural Network trained only on the explanatory parameters achieved excellent results for tumour detection with an F1 score of 0.93 and AUC-ROC of 0.91. Overall, combining hyperspectral imaging with all models shows great potential for in vivo tumour detection, while leveraging physiological explanatory parameters with a Neural Network model can enhance acquisition time and data interpretability without compromising the classification accuracy.

The project's purpose was to investigate the development of a medical sharps waste device appropriate for use and manufacture in Nepal. Medical sharps waste management in Nepal is still somewhat dangerous, despite the physical and environmental dangers.

After considering several design directions, it was determined to create a mechanism capable of mechanically pulling the needle tube out of the hub. A device like this will render needles unusable while simultaneously opening up possibilities for the recycling of the materials of needle waste. Additionally a device that mechanically separates the materials of needles does not currently exist.

Tensile tests were performed with various needle sizes and temperatures to better investigate this. There were no statistically significant differences between temperatures, although the results from 16 G needles differed significantly from the results from 20 G and 23 G needles. It was discovered that the device's minimum pulling force should be 500 N; this, along with information taken from several set standards and previous projects on needle devices, was then included into a set of requirements for the device.

After exploring several clamping, pulling, and combined mechanisms, a roller mechanism was chosen for the device. A functional prototype capable of extracting a needle tube from its hub was created. This prototype was then tested, and various experiments were carried out to try to enhance the design because needle tubes were still slipping in between the rollers on occasion, and some needle tubes broke off.

Adding other structures or a different material like rubber on the rollers did not result in better performance, and a knurling pattern worked best for creating grip on the needle tube. Adding a ridge did not improve the performance, however removing some material from both sides of the gap in Roller A did enhance performance temporarily. Making the rollers out of stainless steel 431 rather than 316 did not increase their performance; however, stainless steel 431 with a heat treatment did improve the performance and showed consistent test results. This final prototype, including the rollers made out of stainless steel 431 with a heat treatment was then used to do final verification and validation.

20 G needles could be pulled with the device consistently at a needle length of 33.8 mm, both wet and dry. 27 G needles however kept breaking off, both wet and dry. A design choice should be made here about if the device should be aimed at a smaller range of needles or a redesign should be made where different spring forces could be applied. The device showed not springback and no parts became trapped in the mechanism.

It was impossible to insert needles of various diameters at greater angles from the vertical of the aperture and 16 G needles did not fit into the device at all. A redesign is needed for this.
The average activation force of the device was 14.72 N and the distance from the hand holding the needle to the hand operating the device did not exceed 50 mm.
The cycle time per needle was still too long for the device. Further research is required to improve these parameters. The prototype did meet the weight and size requirements. The device did not have a sharps box attached to it, this should be added in a redesign.

If the rollers of the device are to be constructed of stainless steel 431, they should be made in India, since stainless steel 431 was not available in Nepal. The case, cubes, pushing plate, socket, spring axis, and lever may all be made in Nepal. Standard components, such as springs and bearings, may be obtained in India. However still choices and more research is needed in the area of where exactly the product should be produced and assembled.
More research is needed to determine how the metal components of needles may be recycled and how a device like this would work with different types of needles. Also researching if applying force to both rollers and a redesign either with a different spring of multiple spring forces should still be done.

More testing is needed to determine the pulling force and how many cycles the device can sustain. As well as a drop test, a tipping test on an angular surface and users tests.
Lastly research into how to incorporate a redesign where the syringe is also rendered unusable is needed, since this study only focused on making the needle part unusable by separating the materials.

Purpose: In percutaneous renal ablation (PRA), reaching the target accurately is challenging due to target motion and limited real-time visualization of the target, requiring a suitable navigation strategy. In the context of this thesis research, skin markers are used in combination with an the Azurion C-arm system (Philips Healthcare, Best, The Netherlands), an image-guided therapy system, equipped with ClarifEye (Philips Healthcare, Best, The Netherlands), an Augmented Reality (AR) surgical navigation system. The skin markers are tracked by ClarifEye, virtually representing the position of the patient. This thesis aims to explore if skin markers can facilitate sufficiently accurate navigation in PRA by investigating the skin marker motion (SMM) and kidney tumor marker motion (TMM) during needle insertion, considering the insertion speed (IS) and level of perirenal fat (LPF). Methods: An ex-vivo porcine kidney model, with simulated skin, tumors and perirenal fat was developed and validated. A skin marker model was constructed on the model. Consequently, 60 robotic-assisted needle insertions were planned with ClarifEye (Philips Healthcare, Best, The Netherlands) navigation and performed on 8 kidney models (4 with low LPF (LLPF), 4 with high LPF (HLPF)), targeting 20 tumors at varying ISs: continuous insertions of 2.5 mm/s, 75 mm/s and consecutive 5 mm increments of 10 mm/s. Cone beam computed tomography (CBCT)-scans were made before and after insertion to analyze SMM and TMM. Results: The SMM (overall mean SMM = 0.16 mm, standard deviation (SD) = 0.14 mm) was smaller than the voxel-size (1D) of dViewX (dicom-viewer software, Philips Healthcare, Best, The Netherlands) (voxel-size 1D = 0.2425 mm), regardless of the direction of the SMM and regardless of the IS and LPF. The TMM values in the z-direction were predominantly negative. The IS and LPF did not impact the amount and direction of TMM.
Conclusion: Any local skin deformation caused by needle insertion resulted in negligible SMM. Although the skin markers do not account for the TMM caused by needle insertions, the median TMM values (1.2-1.9 mm) are still smaller than the minimally required clinical insertion accuracy of 3-5 mm. The acceptable TMM values, in combination with the negligible SMM values, imply that skin markers can be used to facilitate navigation in PRA.

Automatic milking of cows has been around for more than 30 years, making the milking process more efficient, less labour intensive and more cow friendly. Before a cow can be milked, three stages of udder pretreatment have to be completed: cleaning, stimulation and premilking. There is no clearly superior pretreatment technique for automatic milking systems and the three main manufacturers of milking robots (Lely, DeLaval and GEA) each use different systems. Lely uses two counter rotating brushes that the teat is inserted in between, with good cleaning and stimulation results. However, their R&D department is looking for innovative alternatives. The goal of this thesis is therefore to find an innovative alternative for Lely’s current pretreatment system with at least as good cleaning and stimulating properties. Preferably the premilking stage is also included, which Lely’s current system is unable to perform in contrast to its competitors. A morphological chart is used to design three concepts. Prototypes are then evaluated based on a field test with a real cow and a cleaning test using a fake test-teat. Based on a weighted Harris profile, the Origami Vacuum Gripper concept was chosen to further iterate into a final design and prototype. The device is essentially a gripper that functions like a foldable milking cup that sprays, grips and then brushes the teat by being pulled downward off the teat. The folding is based on the Waterbomb origami pattern and is actuated using vacuum and an airtight skin that is wrapped around it. A brush liner is positioned inside the gripper and the dirt is removed at the bottom through a vacuum tube. A final field test showed that the device fulfilled all requirements, being able to properly clean and stimulate the teats and leaving them dry enough to attach the milking cups. Unfortunately, the device was not able to premilk the cow. The compression of the teat by the gripper prevented the milk from being pulled out by the vacuum inside the gripper. Finally, a gripping force test is performed to see the effect of different origami skeleton geometries on the gripping force applied to the teat. It was concluded that the skeleton with shorter folding edges applies a larger force to the teat with the same vacuum applied to the airtight skin. More research is needed on the folding geometries in order to find an optimal design for the gripper.

Background : Surgeons performing robotic-assisted laparoscopic surgery experience physical stress and overuse of shoulder muscles due to sub-optimal arm support during surgery. Following background literature research on passive
dynamic arm supports, this report presents and evaluates a novel design.
Objective: To present a novel design and prototype of a dynamic arm support for robotic laparoscopic surgery and evaluate the arm support for ergonomics and performance on the AdLab-RS simulation training device.
Method : The prototype was designed using the mechanical engineering design process: Technical requirements, concept creation, concept selection, 3D-design in Solidworks, built of the prototype. A crossover study was performed on participants divided into two groups, all performing a marble sorting task on the AdLab-RS. One group first performed four trials without the arm support, followed by four trials with the arm support, and the other group
vice versa. The performance parameters were time to complete (s), path length (mm), and the number of collisions. Afterward, the participants filled out a questionnaire on the ergonomic experience regarding both situations, including
part of the Nasa TLX questionnaire.
Results: A new arm support was developed and a total of 20 students took part in the study on its evaluation, which led to 160 performed trials on the AdLab-RS. Significant decreases in the subjective comfort parameters mental
demand, physical demand, effort and frustration were observed as a result of introducing the novel arm support. Significant decreases in the objective performance parameters path length and the number of collisions were also
observed during the tests.
Conclusion: The newly developed dynamic arm support was found to improve comfort and enhance performance through increased stability on the robotic surgery skills simulator AdLab-RS. However, the study’s limitations, such
as the short trial duration and non-surgeon participants, must be acknowledged when interpreting the results.

Background
The availability of medical ultrasound imaging is still limited in low- and middle-income countries, despite its potential impact on patient outcomes. This problem partially manifests in the limited availability of trained physicians due to the unequal distribution of physicians between rural and urban areas in India. Robotic telesonography offers a solution by allowing physicians to consult a patient remotely. However, current solutions are generally aimed at high-income countries and, therefore, incompatible with the resource-limited setting of low- and middle-income countries [3, 4]. This thesis aims to develop a contextualised design for Indian healthcare of the follower robot of the telesonography system.

Method
The design space of robotic telesonography is analysed to determine the optimal design direction. A mechanical design is selected based on the defined performance parameters according to the local context and
design stage. These are costs, maintenance requirements, functionality and portability. The forward kinematic and static load models are set up to test the theoretical performance. The design is optimised in terms of the kinematic design, the actuation layout and the structural design. Furthermore, an initial prototype is constructed to validate the design and performance by performing a force/deflection test on beam I and a friction measurement in joint θ3.

Results
A detailed design has been realised, conforms to the requirements, that aims to overcome the barriers. The resulting design comprises a remotely controlled serial spherical robotic arm that can orientate the ultrasound probe. The robot can be placed passively by an assistant at the region of interest to cover the full workspace. The force/deflection test reveals a difference between the physical and simulated models due to the nonlinear behaviour of the physical model. The friction test shows that the friction in the bearings does not impede the motion.

Conclusion
This thesis presents a novel design of the follower robot for telesonography. The design is contextualised to the setting of Indian healthcare aiming to overcome the barriers to medical devices in low- and middleincome countries. The design is the first step towards a solution to the limited availability of sonography by targeting the majority of the disease burden.

Introduction Aortic valve regurgitation (AR) is a common type of aortic valve disease that affects the surrounding tissues of the heart. Surgery may be required in patients with acute or chronic AR, aortic root disease or ascending aortic dissection. A viable alternative to traditional aortic valve replacement that offers encouraging clinical outcomes is aortic valve-sparing root replacement (VSRR). However, reoperation due to recurrent or residual AR has a high incidence. Transesophageal echocardiography (TEE) is the gold standard for intraoperatively evaluating residual AR. Evaluation is performed after aortic declamping; therefore, a longer bypass time is inevitable when additional repair is required. Furthermore, quantification of AR with TEE can be challenging. Therefore, the need for an early and quantitative assessment method rises. The main objective of this study was to identify the relationship between the intraoperative and quantitative assessment of the repaired aortic valve and the post-declamping echocardiographic assessment after VSRR. Echocardiographic parameters were studied to find the optimal parameter to identify this relationship. Furthermore, variables that influence the amount of leakage in the quantitative and intraoperative assessment of the repaired valve were identified. Two in vitro experiments were performed to investigate the contribution of these variables to the leakage of sufficient and insufficient aortic valves.

Experiment 1 The effective regurgitant orifice area was the optimal parameter to obtain the relationship between echocardiographic and quantitative assessment. It was implemented in an experimental setup as the orifice area. In addition to this parameter, the contribution of the orifice shape, pressure and fluid viscosity to the leakage was examined using a custom representation of the ascending aorta and the aortic valve. The orifice area was shown to have the most significant contribution to the amount of leakage, followed by the pressure and shape of the orifice. These three variables will be assessed in a second experiment. The viscosity of the fluid did not influence the leakage. 

Experiment 2 In a second experiment, the contribution of different variables to sufficient and insufficient aortic valves was evaluated at different pressures. The experiment was carried out in three cardiac tissues, in which first the contributions to the baseline leakage of a sufficient valve were evaluated. Two methods were used to create insufficiency. The first involved a punch and the second applied a more physiological approach of leaflet manipulation. The graft water permeability and the anastomosis leakage determined the leakage in a sufficient aortic valve state. The leakage of an insufficient aortic valve was almost completely determined by the size of the insufficiency. Graft permeability and anastomosis leakage could be neglected in the insufficient valve state. The leakage of the punched valve was comparable to the expected regurgitant volume based on the echocardiographic guidelines for that area. Leaflet manipulation resulted in less leakage than expected.

Conclusion The contribution of several variables to the leakage of sufficient and insufficient aortic valves was investigated in two in vitro experiments. The results of this study show that the contributions of each of these variables could be quantified. As a result, the leakage of an insufficient aortic valve could be quantified in a static, pressurised in vitro setting. This is the first step in obtaining the relationship between the quantitative amount of leakage and echocardiography, to improve intraoperative assessment of the repaired aortic valve after VSRR.