Since the introduction of robot-assisted laparoscopic surgery, efforts have been made to incorporate force sensing technologies to monitor critical components and to provide force feedback. The advanced laparoscopic robotic system (AdLap RS) is a robotic platform that aims to make robot technology more sustainable through the use of the fully reusable shaft-actuated tip-articulating (SATA) instruments. The SATA instrument driver features electronics and sensors exposed to the sterile environment, which complicate the sterilisation process. The aim of this study was to develop and validate smart sensing in stepper motors using the back electromotive force in a newly developed Smart SATA Driver (SSD), eliminating the need for sensors in the sterile environment. Methods: The stepper drivers were equipped with TMC2209 ICs featuring StallGuard technology to measure back EMF. The tip was actuated up until a set StallGuard threshold value was reached, at which the resulting tip force was measured. This cycle was repeated ten times for a range of threshold levels. A regression analysis with a power series model was used to determine the quality of the fit. Results: The SSD is capable of exerting tip forces between 2.4 and 8.2 N. The back EMF force test demonstrated a strong correlation between obtained StallGuard values and measured tip forces. The regression analysis showed an R-squared of 0.95 and a root Mean squared error of 0.4 N. Discussion: The back EMF force test shows promise for force feedback, but its accuracy limits real-time use due to back EMF fluctuations. Future improvements in motor stability and refining the back EMF model are needed to enable real-time feedback. Conclusion: The strong correlation during the back EMF force test shows its potential as a low-budget method for detecting motor stalls and estimating tool–tissue forces without the need for sensors in laparoscopic instruments.

Background: Totally extraperitoneal (TEP) inguinal hernia surgery is a commonly performed but technically challenging procedure with a long learning curve. As TEP can be executed using two different trocar placements: a midline or a triangular configuration, the question remains which one is technically easier to master. Methods: In a multicenter crossover-study, medical students were randomised into two groups and executed tasks on a box trainer that measured time, volume and force parameters. Additionally, the study assessed whether the SATA instrument, a steerable laparoscopic instrument that articulates the instrument’s tip, would reduce the difficulty of performing the tasks in the midline configuration. After training, all participants executed a first experiment using both trocar configurations, followed by a second experiment executed with steerable and non-steerable instruments in the midline configuration. Subjective and objective performances per condition and learning curves were assessed. Results: Participants were faster and showed lower peak forces in the triangulated configuration. Learning curve analysis showed a positive improvement in time and path length in the midline configuration. Although participants rated ergonomics and intuitiveness similarly between the instruments, they found the task easier with the SATA instruments, ranking the added value of the steering function as 5 out of 5. Objectively, time and path length showed no significant differences while exerted forces were lower when using conventional instruments. Conclusion: Although the midline configuration is preferred in terms of comfort and posture, the findings indicate that, for inexperienced practitioners, performing TEP surgery in midline configuration is both subjectively and objectively more challenging, highlighting the need for extensive training to overcome its difficulties and possibly shorten its learning curve. Although instruments with additional steering functions were preferred over conventional instruments in the more challenging midline configuration, additional steering complexity did not result in better parameter outcomes, showing the need for more extensive training.

Modern medical science stands at the crossroads of technology, precision and innovation. An enormous variety of technological marvels proliferate in modern medical practice, which many take for granted, such as ultrasound, CT and MRI imaging, portable sensors, implants of almost any part of the anatomy including skin, endoscopic contrivances of mind-blowing complexity, robotics, and an abundance of medication quite undreamt of just 50 years ago. [...]

Objective: Central venous catheters (CVCs) provide direct access to the central circulatory system, commonly used in hemodialysis and intensive care units for drug administration. Although uncertified for the procedure, CVCs are sometimes used for power injection of contrast medium (CM) during CT scans to avoid peripheral intravenous catheter placement. Previous studies suggest this practice is safe, but incidents are reported. This study aims to measure intraluminal pressure during CM injection through CVCs and assess its impact on the luminal surface to guide responsible clinical use. Materials and methods: An experimental in vitro test setup was developed. Four samples each of three different types of unused CVCs were used. Strain gauges were applied to the exterior walls of either the inflow or outflow lumen of the CVC. These gauges measured material deformation due to intraluminal pressure during CM injections at rates of 4.5 and 8 mL/s, each performed five times. Strain data were calibrated against known pressures in a static system. Three CVCs of each type were then pressurized until bursting, and one was subjected to microscopic analysis of the luminal surfaces. Results: Intraluminal pressures measured (97–545 kPa or 14–79 PSI) were below the burst pressure (779–1248 kPa or 113–181 PSI) in all instances. Strain regression analysis shows a statistically significant (p < 0.01) trend over 10 injections in all CVCs tested except one, indicating material fatigue. Surface microscopy revealed surface micro-cracks from repeated injections, suggesting material damage. Conclusions: The intraluminal pressures from power injections of CM are sufficiently low to prevent CVC bursting. While incidental use for CM injection appears safe, repeated use may cause material damage.

This book offers a comprehensive roadmap toward a circular and sustainable healthcare system, structured into three distinct parts.

Part I describes circular principles and policy tactics. Chapter 1 outlines the essentials of sustainable healthcare and designates the paradox in daily practice of sustainability and the circular economy. In Chapter 2 the impact of leadership on policy together with best practices is discussed. The legislation and infrastructural web, in which many stakeholders and circular economy initiatives are strangled, is described. Despite the fact that politicians and policymakers are motivated to encourage sustainability, the infrastructure is designed to discourage circular economy projects. This chapter shows examples of setting-up intrinsic motivated teams of hospital staff, green teams, industry leaders and scientific motivated research teams. Swimming against the current is about the legislation paradox. In chapter 3 described as how legislation should be redesigned to accomplish the goals as set out in the green deal and the climate law.

Part II serves as a practical guide to implementing circular strategies. In chapter 4 the reader is guided through the fundamentals of circular strategies by visualizing the circular economy. Chapter 5 reveals successful design strategies for products and processes which contribute to a zero-waste society. Using recycled materials by using waste as input for new products is described in chapter 6. In chapter 6 we will explore (surgical) waste as input for new products. Recycled should and could be used more. This is a fundamental concept within circular design principles but hardly used until this moment.

Part III explores circular economy design principles on basis of successful examples. This part dives into real-world applications and measurable outcomes. It showcases successful circular design concepts and business models that have reshaped the market. Chapter 7: Is about leading by design. Success stories of circular concepts which have effectively changed the market with circular products and services are designated. Also entrepreneurial success stories of circular economy business models are presented. Chapter 8 investigates how to measuring effectiveness and impact of circular economy products and processes. In particular how reliable some facts are which are used by many to sell products or introduce new policies or legislation. How trustworthy is data from life cycle assessments (LCA’s)? What are the pitfalls? Is it possible to manipulate these data? Why should we characterize one-sided data from an LCA as greenwashing? Circular Economy principles, sustainability and, in broader sense, the climate discussion seem to trigger emotions. Using fundamental and reliable data is essential in order to be able to judge whether a product or process indeed reduces CO2 emissions is essential in decision-making. Chapter 9 focusses on how universities can contribute to sustainable solutions by presenting different cases which resulted in actual results which were implemented or are ready for upscaling. The role of universities as innovation hubs is highlighted through case studies with proven impact. The final chapter offers a reflective and forward-looking analysis on how circular strategies in healthcare can shape future societal developments.

The authors reflect on the content in chapter 10. A final part in which a critical analysis is presented and the impact it could have on future developments and the society.

Background: Technological innovations have significantly enhanced the objective assessment of technical skills in minimally invasive surgery, offering substantial potential for proficiency-based training. However, the integration of these innovative tools into surgical education curricula remains limited. This study aims to evaluate the adoption and implementation of data-driven assessment tools within laparoscopic simulation training. Methods: A systematic search of PubMed and Embase was conducted following PRISMA guidelines, identifying studies that employed objective assessments of technical skills in surgical training curricula. Eligible studies utilized data-driven assessment methods as part of structured training programs for surgical residents. A descriptive analysis was performed on the included studies. Results: From 2814 identified articles, 718 were eligible for full-text screening, and 35 studies met the inclusion criteria. These studies described the implementation of 14 different data-driven tools in laparoscopic skills training. Most tools focused on assessing instrument handling, measuring parameters such as motion speed, path length, and accuracy. Only three studies evaluated tissue handling skills using metrics like knot quality, tissue handling forces, and anastomotic integrity. Conclusions: The adoption of data-driven tools in laparoscopic simulation training is progressing slowly and exhibits considerable variability. Most technologies emphasize instrument handling, while tools for assessing tissue manipulation and force application are limited. To improve training outcomes, a combination of motion- and force-based assessment tools should be considered, enabling a more comprehensive evaluation of technical skills in minimally invasive surgery.

Background: To validate whether the SATA-LRS, a novel reusable articulating laparoscopic instrument, fits surgical practice, a pre-clinical study was performed. Methods: Thirteen medical doctors used the instrument in a laparoscopic endoscopic inguinal hernia repair (TEP)-like task inside a cadaver. A set of sensors on the instrument handle detected motion and articulation of the instrument tip. Data from the sensors and video recordings were used to assess the amount and type of movement of the instrument and the time spent on tasks. questionnaire was used to gain insight into the participants’ perception of the contextual factors. Results: There was no difference between task time and instrument tip velocities when using articulation (or not) and all participants used articulation at least half of the task time. Instrument-handle movement, indicating the user’s hand and arm movement, was significantly reduced when using articulation. The questionnaire indicated strong acceptance of the instrument and the experimental setup, and a desire to use the instrument in surgery by most participants. Conclusions: The added articulation feature of the SATA-LRS instrument was deemed beneficial by the participants, showed no increased handling complexity or time spent on the task and was used frequently when enabled, indicating intuitiveness.

Background: Laparoscopic surgery requires a complex set of motor skills. Currently, basic laparoscopic skills training is performed in a static environment, while intraoperatively, abdominal tissue is often moving. The aim of this study was to develop a dynamic training platform and evaluate its impact on laparoscopic skills acquisition in a box trainer. Methods: The Dynamic Laparoscopic Platform (DyLaP) includes a moving base which has been intergrated with the Lapron box trainer and the ForceSense objective measurement system. Dynamic training was evaluated in a comparative study where novices were divided into a static and dynamic training group, performing six training trials of a peg transfer task with the DyLaP. Afterwards, both groups performed a dynamic exam task. Task manipulation (force) and instrument efficiency (path length and time) were measured. Results: Participants (n = 12) exhibited a significant difference (p < 0.05) in time, path length, and maximum force between the static and dynamic groups in the first trial. Learning curves were most prevalent in the dynamic group. Conclusions: The DyLaP can be used to provide a challenging and realistic training environment. From the comparative peg transfer study, it can be concluded that dynamic training significantly affects laparoscopic skill acquisition. More research is needed to evaluate dynamic training effects in force-based training tasks.

Objective: Hemodialysis patients usually receive an arteriovenous fistula (AVF) in the arm as vascular access conduit to allow dialysis 2-3 times a week. This AVF introduces the high flow necessary for dialysis, but over time the ever-present supraphysiological flow is the leading cause of complications. This study aims to develop an implantable device able to non-invasively remove the high flow outside dialysis sessions. Methods: The developed prototype features a magnetic ring allowing external coupling and torque transmission to non-invasively control an AVF valve. Mock-up devices were implanted into arm and sheep cadavers to test sizes and locations. The transmission torque, output force, and valve closure are measured for different representative skin thicknesses. Results: The prototype was placed successfully into arm and sheep cadavers. In the prototype, a maximum output force of 78.9 ± 4.2 N, 46.7 ± 1.9 N, 25.6 ± 0.7 N, 13.5 ± 0.6 N and 6.3 ± 0.4 N could be achieved non-invasively through skin thicknesses of 1-5 mm respectively. The fistula was fully collapsible in every measurement through skin thickness up to the required 4 mm. Conclusion: The prototype satisfies the design requirements. It is fully implantable and allows closure and control of an AVF through non-invasive torque transmission. In vivo studies are pivotal in assessing functionality and understanding systemic effects. Significance: A method is introduced to transfer large amounts of energy to a medical implant for actuation of a mechanical valve trough a closed surface. This system allows non-invasive control of an AVF to reduce complications related to the permanent high flow in conventional AVFs.

Collision feedback about instrument and environment interaction is often lacking in robotic surgery training devices. The PoLaRS virtual reality simulator is a newly developed desk trainer that overcomes drawbacks of existing robot trainers for advanced laparoscopy. This study aimed to assess the effect of haptic and visual feedback during training on the performance of a robotic surgical task. Robotic surgery-naïve participants were randomized and equally divided into two training groups: Haptic and Visual Feedback (HVF) and No Haptic and Visual Feedback. Participants performed two basic virtual reality training tasks on the PoLaRS system as a pre- and post-test. The measurement parameters Time, Tip-to-tip distance, Path length Left/Right and Collisions Left/Right were used to analyze the learning curves and statistically compare the pre- and post-tests performances. In total, 198 trials performed by 22 participants were included. The visual and haptic feedback did not negatively influence the time to complete the tasks. Although no improvement in skill was observed between pre- and post-tests, the mean rank of the number of collisions of the right grasper (dominant hand) was significantly lower in the HVF feedback group during the second post-test (Mean Rank = 8.73 versus Mean Rank = 14.27, U = 30.00, p = 0.045). Haptic and visual feedback during the training on the PoLaRS system resulted in fewer instrument collisions. These results warrant the introduction of haptic feedback in subjects with no experience in robotic surgery. The PoLaRS system can be utilized to remotely optimize instrument handling before commencing robotic surgery in the operating room.

Surgeons performing robotic-assisted laparoscopic surgery experience physical stress and overuse of shoulder muscles due to sub-optimal arm support during surgery. The objective is to present a novel design and prototype of a dynamic arm support for robotic laparoscopic surgery to evaluate its ergonomics and performance on the AdLap-VR simulation training device. The prototype was designed using the mechanical engineering design process: Technical requirements, concept creation, concept selection, 3D-design and built of the prototype. A crossover study was performed on a marble sorting task on the AdLap-VR. The first group performed four trials without the arm support, followed by four trials with the arm support, and the other group executed the sequence vice versa. The performance parameters used 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. 20 students executed 160 performed trials on the AdLap-VR 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. The newly developed dynamic arm support was found to improve comfort and enhance performance through increased stability on the robotic surgery skills simulator AdLap-VR.

Hospitals in Europe produce approximately 6 million tons of medical waste annually, about one-third of this originating in operating rooms. Most of it is solid waste, which can be recycled if bodily fluids do not contaminate it. Only 2–3% of hospital waste must be disposed of as infectious waste, and this is much lower than the 50–70% of garbage in the biohazard waste stream. In June 2021, at the main operating room of the Department of General Surgery of the University of Turin, we began a separate collection program for materials consisting of plastic, paper, TNT (material not contaminated by bodily fluids), and biohazardous waste. We calculated the number of boxes and the weight of special waste disposed produced every month in one operating room for 18 months. The monthly number of Sanibox and the monthly weight of biohazardous waste decreased during the observation period. The reduction trend was not constant but showed variations during the 18 months. Direct proportionality between number of low-complexity procedures and production of biohazardous waste was found (p = 0.050). We observed an optimization in the collection and filling of plastic, paper and TNT boxes separated and sent for recycling. One of the barriers to recycling hospital waste, and surgical waste in particular, is the failure to separate infectious waste from clean waste. A careful separate collection of waste in the operating room is the first step in reducing environmental pollution and management costs for the disposal of hospital waste.

Objective: Cemented total hip arthroplasty (THA) demonstrates superior survival rates compared to uncemented procedures. Nevertheless, most younger patients opt for uncemented THA, as removing well-fixed bone cement in the femur during revisions is complex, particularly the distal cement plug. This removal procedure often increases the risk of femoral fracture or perforation, haemorrhage and weakening bone due to poor drill control and positioning. Aim of this study was to design a novel drill guide to improve drill positioning. Methods and procedures: A novel orthopaedic drill guide was developed, featuring a compliant centralizer activated by a drill guide actuator. Bone models were prepared to assess centralizing performance. Three conditions were tested: drilling without guidance, guided drilling with centralizer activation held, and guided drilling with centralizer activation released. Deviations from the bone centre were measured at the entry and exit point of the drill. Results: In the centralizing performance test, the drill guide significantly reduced drill hole deviations in both entry and exit points compared to the control (p < 0.05). The absolute deviation on the exit side of the cement plug was 10.59mm (SD 1.56) for the 'No drill guide' condition, 3.02mm (SD 2.09) for 'Drill guide - hold' and 2.12mm (SD 1.71) for 'Drill guide - release'. The compliant drill guide centralizer significantly lowered the risk of cortical bone perforation during intramedullary canal drilling in the bone models due to better control of the cement drill position. Clinical and Translational Impact Statement: The drill guide potentially reduces perioperative risks in cemented femoral stem revision. Future research should identify optimal scenarios for its application.

Introduction: Most robotic instruments and their drives still risk residual contamination due to cleaning complexities, rendering them limited reusable, and tend to have larger instruments than the 5mm laparoscopic standard. The novel steerable laparoscopic SATA-LRS uses modularity for cleanability and exchangeability. The SATA-Drive: a robotic driver designed for the actuation of a 3mm scaled version of the SATA-LRS is presented. Methods: A modular, expandable gear mechanism was designed to efficiently rotate and translate the instrument shafts. The 3mm SATA-LRS is controlled as proof. An user-experiment is conducted to test the (de)coupling of the instrument to and from the drive. Results: A video shows the SATA-Driver successfully articulating, rotating and grasping the end-effector. End-effector dis- and reassembly is possible in 36 (13 SD) seconds, while complete instrument coupling requires 28(8 SD) seconds and de-coupling requires 16 (7 SD) seconds. Discussion: A non-surgical robot arm, mounted with the SATA-drive has effectively been transformed into a system similar to robot assisted laparoscopy. The modularity of the drive's segmented build can easily be adapted and could benefit the adoption of future instruments. The SATA-LRS's cleanability features and its end-effector changes without disassembly are expected to benefit medical robotics. The 3mm SATA-LRS shows the instrument's potential for mini-laparoscopy.

In de afgelopen decennia is het aantal medische wegwerpproducten significant toegenomen. Binnen het bedrijf GreenCycl en het GreenCycl Fieldlab worden oplossingen gezocht om de schaarste van grondstoffen tegen te gaan. Diverse methoden zijn onderzocht om medisch afval na gebruik opnieuw in te zetten als product, instrumentonderdelen of grondstof. De methoden volgen de strategieën van de Butterfly Diagram van de Ellen MacArthur Foundation. Een mix van deze strategieën is onderzocht en toegepast op vijf afvalstromen van de operatiekamer: complexe endoscopische instrumenten, herbruikbare instrumenten van roestvast staal, wegwerpinstrumenten van roestvast staal, instrumenten met inpakpapier van polypropyleen (PP) en verpakkingsmateriaal van polyethyleentereftalaat (PET). De vijf afvalstromen hebben hun eigen specifieke verwerkingsproces en verschillen in de benodigde hoeveelheid energie. Alle strategieën verminderen de CO2-uitstoot met 2,2-3 kg CO2 per kg afval. In alle gevallen blijkt het materiaal zijn eigenschappen grotendeels te behouden. Dit maakt de circulaire strategieën toepasbaar voor elk ziekenhuis.

Hospital waste streams can be minimized or even eliminated by using circular strategies. Reduce: Use less disposable instruments and more reusable instruments. Reuse: Repair of instruments instead of replacement. Recycle: Packaging was recycled, wrapping paper and steel waste into new materials. New products were manufactured out of recycled hospital waste. Cultural change is needed including creating awareness, change of workflows of transcending departments are needed. Presentation of the conference of the World Sterilization Federation WFHSS in Brussels, October 2023. Title: "CIRCULAR ECONOMY STRATEGIES TO REDUCE MEDICAL WASTE STREAMS" https://wfhss.com/world-congress-2023-bruxelles-belgium/

In laparoscopic surgery, quality of haptic feedback is reduced compared to conventional surgery, leading to unintentional tissue damage during grasping. From the perspective of haptics, poor mechanical design of laparoscopic instrument joints induces friction and a nonlinear actuation-tip force relation. In this study, a novel laparoscopic grasper using compliant joints and a magnetic balancer is presented, and the reduction in hysteresis and friction is evaluated. The hysteresis loop of the novel compliant grasper and two conventional laparoscopic graspers (high quality leading commercial brand and low quality unbranded grasper) were measured. In order to assess quality of haptic feedback, the lowest grasper tip load perceivable by instrument users was measured with the novel and the conventional laparoscopic graspers. The hysteresis loop measurement yielded a mechanical efficiency of 43% for the novel grasper, compared to- 25% and 23% for the Aesculap and the unbranded grasper, respectively. The forces perceivable by the user through the novel grasper were significantly lower (mean 1.37N, SD 0.44N) than those of conventional graspers (mean 2.15N, SD 0.71N and mean 2.65N, SD 1.20N, respectively). The balanced compliant grasper technology has the ability to improve the quality of haptic feedback compared to conventional laparoscopic graspers. Research is needed to relate these results to soft and delicate tissue grasping in a clinical setting, for which this instrument is intended.

Mechanical stress influences scarring of a surgical wound. Several lines have been proposed for the best excision direction. It is unknown if these lines still apply when the body posture changes. The objective is to measure the skin reaction force in four directions and determine the direction of least force. Secondary objective is to determine if the reaction force varies in a different body posture. Skin reaction force was measured with the compressiometer in 30 participants on four different locations (forearm/upper arm/shoulder blade/lower back) in four directions (0°–45°–90°–135°) and two body postures. The direction of least skin reaction force changed with a different body posture and was significant for the forearm (p < 0.01) and shoulder blade (p = 0.05) The skin reaction force in all four direction changed significantly in a different body posture, except the 45° line in the upper arm and shoulder blade. Our results demonstrate that the skin reaction force in four directions in four locations varies with change in body posture. Focus should therefore not only lay on choosing the right direction, but also on managing skin tension postoperatively.

Introduction: Robot-assisted surgery is often performed by experienced laparoscopic surgeons. However, this technique requires a different set of technical skills and surgeons are expected to alternate between these approaches. The aim of this study is to investigate the crossover effects when switching between laparoscopic and robot-assisted surgery. Methods: An international multicentre crossover study was conducted. Trainees with distinctly different levels of experience were divided into three groups (novice, intermediate, expert). Each trainee performed six trials of a standardized suturing task using a laparoscopic box trainer and six trials using the da Vinci surgical robot. Both systems were equipped with the ForceSense system, measuring five force-based parameters for objective assessment of tissue handling skills. Statistical comparison was done between the sixth and seventh trial to identify transition effects. Unexpected changes in parameter outcomes after the seventh trial were further investigated. Results: A total of 720 trials, performed by 60 participants, were analysed. The expert group increased their tissue handling forces with 46% (maximum impulse 11.5 N/s to 16.8 N/s, p = 0.05), when switching from robot-assisted surgery to laparoscopy. When switching from laparoscopy to robot-assisted surgery, intermediates and experts significantly decreased in motion efficiency (time (sec), resp. 68 vs. 100, p = 0.05, and 44 vs. 84, p = 0.05). Further investigation between the seventh and ninth trial showed that the intermediate group increased their force exertion with 78% (5.1 N vs. 9.1 N, p = 0.04), when switching to robot-assisted surgery. Conclusion: The crossover effects in technical skills between laparoscopic and robot-assisted surgery are highly depended on the prior experience with laparoscopic surgery. Where experts can alternate between approaches without impairment of technical skills, novices and intermediates should be aware of decay in efficiency of movement and tissue handling skills that could impact patient safety. Therefore, additional simulation training is advised to prevent from undesired events.

Background: During laparoscopic surgery, CO₂ insufflation gas could leak from the intra-abdominal cavity into the operating theater. Medical staff could therefore be exposed to hazardous substances present in leaked gas. Although previous studies have shown that leakage through trocars is a contributing factor, trocar performance over longer periods remains unclear. This study investigates the influence of prolonged instrument manipulation on gas leakage through trocars. Methods: Twenty-five trocars with diameters ranging from 10 to 15 mm were included in the study. An experimental model was developed to facilitate instrument manipulation in a trocar under loading. The trocar was mounted to a custom airtight container insufflated with CO₂ to a pressure of 15 mmHg, similar to clinical practice. A linear stage was used for prolonged instrument manipulation. At the same time, a fixed load was applied radially to the trocar cannula to mimic the reaction force of the abdominal wall. Gas leakage was measured before, after, and during instrument manipulation. Results: After instrument manipulation, leakage rates per trocar varied between 0.0 and 5.58 L/min. No large differences were found between leakage rates before and after prolonged manipulation in static and dynamic measurements. However, the prolonged instrument manipulation did cause visible damage to two trocars and revealed unintended leakage pathways in others that can be related to production flaws. Conclusion: Prolonged instrument manipulation did not increase gas leakage rates through trocars, despite damage to some individual trocars. Nevertheless, gas leakage through trocars occurs and is caused by different trocar-specific mechanisms and design issues.