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P.D. Robertson
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1
Rural India faces many challenges in providing adequate health care for all. Health awareness among the Indian population is low due to poor functional literacy and low emphasis on education within the health sector.
Minimally Invasive Surgery (MIS), such as laparoscopy, offers many advantages, including smaller incisions, less tissue damage and faster recovery for patients compared to traditional open surgery. The use of laparoscopy in low- and middle-income countries (LMICs) is particularly influential because it can minimise the morbidity associated with laparotomies and provide benefits such as fewer postoperative infections and faster return to work. The laparoscopic instruments must be carefully cleaned and sterilised after each use to prevent infection. In any surgery, there is a risk of infection. Postoperative wound infections (POWIs) occur after surgery on the part of the body being operated on. Globally, the rate of POWIs varies between 0.5 and 15 per cent, while in India, rates between 23 and 38 per cent are consistently measured (Arora et al., 2018). These complications lead to revision surgery, delayed wound healing, increased use of antibiotics and longer hospital stay, all of which have a significant impact on patients and healthcare costs. Antimicrobial resistance (AMR) is one of the greatest threats to human health we face worldwide. (World Health Organisation, 2012a, 2012b).
This project focuses on making minimally invasive surgery such as laparoscopy safely applicable in low- and middle-income countries through a medical washer. It aims to find a research-based solution to improve the reprocessing of laparoscopic instruments to reduce POWIs and the need for antibiotics. The current method of reprocessing in hospitals in rural India does not result in sterile laparoscopic instruments and is harmful to patient, nurse and all other staff present in the OR. Instruments are also damaged during the cleaning process. These problems mainly stem from lack of training of nurses, time pressure and due to lack of cleaning equipment.
The project approach was implemented using the Double Diamond Design Model. In the final phase, a prototype was built and this prototype was evaluated in the context of rural India. The aim of this study was to investigate the medical washer loading system for laparoscopic instruments in rural hospitals and to understand how the loading system is used by nurses without any prior explanation. We also investigated how the concept of the medical washing machine is perceived by the end user.
The medical washer for laparoscopic instruments for the context of rural India has been developed can improve current reprocessing practices. By automating the cleaning process, the medical washer reduces the risk of human error and ensures that instruments are thoroughly cleaned. The inclusion of a loading system that can be used without extensive training ensures that the system can be used safely and correctly by all healthcare workers. With the combination of these systems in an integrated design, the medical washer can additionally provide value by reducing cleaning time and allowing nurses to take rest breaks or do other tasks.
...
Minimally Invasive Surgery (MIS), such as laparoscopy, offers many advantages, including smaller incisions, less tissue damage and faster recovery for patients compared to traditional open surgery. The use of laparoscopy in low- and middle-income countries (LMICs) is particularly influential because it can minimise the morbidity associated with laparotomies and provide benefits such as fewer postoperative infections and faster return to work. The laparoscopic instruments must be carefully cleaned and sterilised after each use to prevent infection. In any surgery, there is a risk of infection. Postoperative wound infections (POWIs) occur after surgery on the part of the body being operated on. Globally, the rate of POWIs varies between 0.5 and 15 per cent, while in India, rates between 23 and 38 per cent are consistently measured (Arora et al., 2018). These complications lead to revision surgery, delayed wound healing, increased use of antibiotics and longer hospital stay, all of which have a significant impact on patients and healthcare costs. Antimicrobial resistance (AMR) is one of the greatest threats to human health we face worldwide. (World Health Organisation, 2012a, 2012b).
This project focuses on making minimally invasive surgery such as laparoscopy safely applicable in low- and middle-income countries through a medical washer. It aims to find a research-based solution to improve the reprocessing of laparoscopic instruments to reduce POWIs and the need for antibiotics. The current method of reprocessing in hospitals in rural India does not result in sterile laparoscopic instruments and is harmful to patient, nurse and all other staff present in the OR. Instruments are also damaged during the cleaning process. These problems mainly stem from lack of training of nurses, time pressure and due to lack of cleaning equipment.
The project approach was implemented using the Double Diamond Design Model. In the final phase, a prototype was built and this prototype was evaluated in the context of rural India. The aim of this study was to investigate the medical washer loading system for laparoscopic instruments in rural hospitals and to understand how the loading system is used by nurses without any prior explanation. We also investigated how the concept of the medical washing machine is perceived by the end user.
The medical washer for laparoscopic instruments for the context of rural India has been developed can improve current reprocessing practices. By automating the cleaning process, the medical washer reduces the risk of human error and ensures that instruments are thoroughly cleaned. The inclusion of a loading system that can be used without extensive training ensures that the system can be used safely and correctly by all healthcare workers. With the combination of these systems in an integrated design, the medical washer can additionally provide value by reducing cleaning time and allowing nurses to take rest breaks or do other tasks.
...
Rural India faces many challenges in providing adequate health care for all. Health awareness among the Indian population is low due to poor functional literacy and low emphasis on education within the health sector.
Minimally Invasive Surgery (MIS), such as laparoscopy, offers many advantages, including smaller incisions, less tissue damage and faster recovery for patients compared to traditional open surgery. The use of laparoscopy in low- and middle-income countries (LMICs) is particularly influential because it can minimise the morbidity associated with laparotomies and provide benefits such as fewer postoperative infections and faster return to work. The laparoscopic instruments must be carefully cleaned and sterilised after each use to prevent infection. In any surgery, there is a risk of infection. Postoperative wound infections (POWIs) occur after surgery on the part of the body being operated on. Globally, the rate of POWIs varies between 0.5 and 15 per cent, while in India, rates between 23 and 38 per cent are consistently measured (Arora et al., 2018). These complications lead to revision surgery, delayed wound healing, increased use of antibiotics and longer hospital stay, all of which have a significant impact on patients and healthcare costs. Antimicrobial resistance (AMR) is one of the greatest threats to human health we face worldwide. (World Health Organisation, 2012a, 2012b).
This project focuses on making minimally invasive surgery such as laparoscopy safely applicable in low- and middle-income countries through a medical washer. It aims to find a research-based solution to improve the reprocessing of laparoscopic instruments to reduce POWIs and the need for antibiotics. The current method of reprocessing in hospitals in rural India does not result in sterile laparoscopic instruments and is harmful to patient, nurse and all other staff present in the OR. Instruments are also damaged during the cleaning process. These problems mainly stem from lack of training of nurses, time pressure and due to lack of cleaning equipment.
The project approach was implemented using the Double Diamond Design Model. In the final phase, a prototype was built and this prototype was evaluated in the context of rural India. The aim of this study was to investigate the medical washer loading system for laparoscopic instruments in rural hospitals and to understand how the loading system is used by nurses without any prior explanation. We also investigated how the concept of the medical washing machine is perceived by the end user.
The medical washer for laparoscopic instruments for the context of rural India has been developed can improve current reprocessing practices. By automating the cleaning process, the medical washer reduces the risk of human error and ensures that instruments are thoroughly cleaned. The inclusion of a loading system that can be used without extensive training ensures that the system can be used safely and correctly by all healthcare workers. With the combination of these systems in an integrated design, the medical washer can additionally provide value by reducing cleaning time and allowing nurses to take rest breaks or do other tasks.
Minimally Invasive Surgery (MIS), such as laparoscopy, offers many advantages, including smaller incisions, less tissue damage and faster recovery for patients compared to traditional open surgery. The use of laparoscopy in low- and middle-income countries (LMICs) is particularly influential because it can minimise the morbidity associated with laparotomies and provide benefits such as fewer postoperative infections and faster return to work. The laparoscopic instruments must be carefully cleaned and sterilised after each use to prevent infection. In any surgery, there is a risk of infection. Postoperative wound infections (POWIs) occur after surgery on the part of the body being operated on. Globally, the rate of POWIs varies between 0.5 and 15 per cent, while in India, rates between 23 and 38 per cent are consistently measured (Arora et al., 2018). These complications lead to revision surgery, delayed wound healing, increased use of antibiotics and longer hospital stay, all of which have a significant impact on patients and healthcare costs. Antimicrobial resistance (AMR) is one of the greatest threats to human health we face worldwide. (World Health Organisation, 2012a, 2012b).
This project focuses on making minimally invasive surgery such as laparoscopy safely applicable in low- and middle-income countries through a medical washer. It aims to find a research-based solution to improve the reprocessing of laparoscopic instruments to reduce POWIs and the need for antibiotics. The current method of reprocessing in hospitals in rural India does not result in sterile laparoscopic instruments and is harmful to patient, nurse and all other staff present in the OR. Instruments are also damaged during the cleaning process. These problems mainly stem from lack of training of nurses, time pressure and due to lack of cleaning equipment.
The project approach was implemented using the Double Diamond Design Model. In the final phase, a prototype was built and this prototype was evaluated in the context of rural India. The aim of this study was to investigate the medical washer loading system for laparoscopic instruments in rural hospitals and to understand how the loading system is used by nurses without any prior explanation. We also investigated how the concept of the medical washing machine is perceived by the end user.
The medical washer for laparoscopic instruments for the context of rural India has been developed can improve current reprocessing practices. By automating the cleaning process, the medical washer reduces the risk of human error and ensures that instruments are thoroughly cleaned. The inclusion of a loading system that can be used without extensive training ensures that the system can be used safely and correctly by all healthcare workers. With the combination of these systems in an integrated design, the medical washer can additionally provide value by reducing cleaning time and allowing nurses to take rest breaks or do other tasks.
Improving parametric load release with the Non-Condensing Gasses sensor
In steam sterilization for medical equipment
Steam sterilization is widely used in healthcare and pharmaceutical settings to ensure the effective decontamination of instruments and materials. While pressure is often associated with sterilization processes, it is not a sterilization parameter itself; instead, steam composition plays a crucial role. This thesis investigates the use of a Non-Condensable Gases (NCG) sensor to actively measure steam composition, with the aim of improving the parametric load release process.
The sterilization conditions currently applied originate from research conducted in the 1960s and remain in use today. These conditions include a sterilization temperature between 134 °C and 137 °C, a sterilization time of at least three minutes, and limits on non-condensable gases of ≤5 % within the load and ≤0.1 % in the free space of the chamber. Additionally, the standard specifies a limit of 3.5 % VNCGs per 100 ml of condensate, based on historical measurements performed in steam supply lines rather than inside the sterilization chamber.
To evaluate the potential of direct chamber measurements, experiments were performed using a sterilizer equipped with an NCG sensor and a needle valve that allowed controlled air leakage into the chamber. Four sterilization programs were tested. Each program began with a reference cycle without leakage, followed by cycles in which leaks were introduced at different stages during the conditioning phase. Two additional cycles were conducted with a load inside the chamber to assess the influence of load presence on NCG levels. Furthermore, theoretical calculations were performed to estimate the percentage of NCG per 100 ml of condensate using dilution factor calculations.
In total, 37 sterilization cycles were conducted. The results were evaluated based on sterilization time, temperature, and the percentage of NCGs measured during the holding phase. Three main findings emerged: steam composition varied significantly between cycles, air leakage occurring after the final vacuum phase produced the highest NCG peaks, and sterilization cycles could pass based on time and temperature alone while still failing when steam composition was considered. Although all cycles met the required time and temperature criteria, 9 out of the 37 cycles failed due to excessive NCG levels in the chamber.
The results demonstrate that the use of an NCG sensor can significantly improve the parametric load release process by enabling real-time monitoring of steam composition inside the sterilization chamber. This capability helps identify cycles that would otherwise be incorrectly approved, supports corrective actions when necessary, and reduces unnecessary re-sterilization. As a result, the NCG sensor contributes to improved process reliability, time efficiency, and reduced equipment wear. ...
The sterilization conditions currently applied originate from research conducted in the 1960s and remain in use today. These conditions include a sterilization temperature between 134 °C and 137 °C, a sterilization time of at least three minutes, and limits on non-condensable gases of ≤5 % within the load and ≤0.1 % in the free space of the chamber. Additionally, the standard specifies a limit of 3.5 % VNCGs per 100 ml of condensate, based on historical measurements performed in steam supply lines rather than inside the sterilization chamber.
To evaluate the potential of direct chamber measurements, experiments were performed using a sterilizer equipped with an NCG sensor and a needle valve that allowed controlled air leakage into the chamber. Four sterilization programs were tested. Each program began with a reference cycle without leakage, followed by cycles in which leaks were introduced at different stages during the conditioning phase. Two additional cycles were conducted with a load inside the chamber to assess the influence of load presence on NCG levels. Furthermore, theoretical calculations were performed to estimate the percentage of NCG per 100 ml of condensate using dilution factor calculations.
In total, 37 sterilization cycles were conducted. The results were evaluated based on sterilization time, temperature, and the percentage of NCGs measured during the holding phase. Three main findings emerged: steam composition varied significantly between cycles, air leakage occurring after the final vacuum phase produced the highest NCG peaks, and sterilization cycles could pass based on time and temperature alone while still failing when steam composition was considered. Although all cycles met the required time and temperature criteria, 9 out of the 37 cycles failed due to excessive NCG levels in the chamber.
The results demonstrate that the use of an NCG sensor can significantly improve the parametric load release process by enabling real-time monitoring of steam composition inside the sterilization chamber. This capability helps identify cycles that would otherwise be incorrectly approved, supports corrective actions when necessary, and reduces unnecessary re-sterilization. As a result, the NCG sensor contributes to improved process reliability, time efficiency, and reduced equipment wear. ...
Steam sterilization is widely used in healthcare and pharmaceutical settings to ensure the effective decontamination of instruments and materials. While pressure is often associated with sterilization processes, it is not a sterilization parameter itself; instead, steam composition plays a crucial role. This thesis investigates the use of a Non-Condensable Gases (NCG) sensor to actively measure steam composition, with the aim of improving the parametric load release process.
The sterilization conditions currently applied originate from research conducted in the 1960s and remain in use today. These conditions include a sterilization temperature between 134 °C and 137 °C, a sterilization time of at least three minutes, and limits on non-condensable gases of ≤5 % within the load and ≤0.1 % in the free space of the chamber. Additionally, the standard specifies a limit of 3.5 % VNCGs per 100 ml of condensate, based on historical measurements performed in steam supply lines rather than inside the sterilization chamber.
To evaluate the potential of direct chamber measurements, experiments were performed using a sterilizer equipped with an NCG sensor and a needle valve that allowed controlled air leakage into the chamber. Four sterilization programs were tested. Each program began with a reference cycle without leakage, followed by cycles in which leaks were introduced at different stages during the conditioning phase. Two additional cycles were conducted with a load inside the chamber to assess the influence of load presence on NCG levels. Furthermore, theoretical calculations were performed to estimate the percentage of NCG per 100 ml of condensate using dilution factor calculations.
In total, 37 sterilization cycles were conducted. The results were evaluated based on sterilization time, temperature, and the percentage of NCGs measured during the holding phase. Three main findings emerged: steam composition varied significantly between cycles, air leakage occurring after the final vacuum phase produced the highest NCG peaks, and sterilization cycles could pass based on time and temperature alone while still failing when steam composition was considered. Although all cycles met the required time and temperature criteria, 9 out of the 37 cycles failed due to excessive NCG levels in the chamber.
The results demonstrate that the use of an NCG sensor can significantly improve the parametric load release process by enabling real-time monitoring of steam composition inside the sterilization chamber. This capability helps identify cycles that would otherwise be incorrectly approved, supports corrective actions when necessary, and reduces unnecessary re-sterilization. As a result, the NCG sensor contributes to improved process reliability, time efficiency, and reduced equipment wear.
The sterilization conditions currently applied originate from research conducted in the 1960s and remain in use today. These conditions include a sterilization temperature between 134 °C and 137 °C, a sterilization time of at least three minutes, and limits on non-condensable gases of ≤5 % within the load and ≤0.1 % in the free space of the chamber. Additionally, the standard specifies a limit of 3.5 % VNCGs per 100 ml of condensate, based on historical measurements performed in steam supply lines rather than inside the sterilization chamber.
To evaluate the potential of direct chamber measurements, experiments were performed using a sterilizer equipped with an NCG sensor and a needle valve that allowed controlled air leakage into the chamber. Four sterilization programs were tested. Each program began with a reference cycle without leakage, followed by cycles in which leaks were introduced at different stages during the conditioning phase. Two additional cycles were conducted with a load inside the chamber to assess the influence of load presence on NCG levels. Furthermore, theoretical calculations were performed to estimate the percentage of NCG per 100 ml of condensate using dilution factor calculations.
In total, 37 sterilization cycles were conducted. The results were evaluated based on sterilization time, temperature, and the percentage of NCGs measured during the holding phase. Three main findings emerged: steam composition varied significantly between cycles, air leakage occurring after the final vacuum phase produced the highest NCG peaks, and sterilization cycles could pass based on time and temperature alone while still failing when steam composition was considered. Although all cycles met the required time and temperature criteria, 9 out of the 37 cycles failed due to excessive NCG levels in the chamber.
The results demonstrate that the use of an NCG sensor can significantly improve the parametric load release process by enabling real-time monitoring of steam composition inside the sterilization chamber. This capability helps identify cycles that would otherwise be incorrectly approved, supports corrective actions when necessary, and reduces unnecessary re-sterilization. As a result, the NCG sensor contributes to improved process reliability, time efficiency, and reduced equipment wear.
Effective cleaning of hollow medical devices using fluid mechanics
The influence of flow rate on the cleaning performance
Cleaning is an important factor in the reprocessing of hollow medical instruments. Inadequate cleaning disturbs the disinfection and sterilization process and increases the risk of cross-contamination. An automated washer-disinfector is often used for cleaning medical instruments, by using fluid flow. fluid flow induces shear stress at the wall of medical instruments and is able to detach contamination from the surface. However, there is a lack of studies on the effect of flow rate on the cleaning performance. Also in the ISO standards, no flow requirements can be found to remove contamination. In this study, the relationship between the flow rate and removed mass fraction at different soaking times is investigated to get more insight in the effect of fluid flow on the cleaning performance. The results in this study show that, for smooth tubes with a diameter of 9 mm, the removed mass fraction increases for flow rates up to 7.1 L/min where after the removed mass fraction stagnates. An ANOVA test was performed in combination with a Tukey HSD multiple comparison test to determine significant effects. There is a significant difference in the mass fraction removed, by applying different flow rates (F = 88.24, p = 9.49*10^-33) and different soaking times (F = 15.35, p = 2.8*10^-6), with F as the test statistic from the F-test and p as the p-value. The Tukey HSD test shows significant difference comparing flow rates greater than 5.9 L/min with flow rates smaller or equal to 5.1 L/min. For cleaning with 7.1 L/min, 5.9 L/min or 8.0 L/min no significant differences in the results are found. Furthermore, no
significant differences in the cleaning performance of flushing with 3.5 L/min compared to lower flow rates is found. Moreover, this study shows that there is a significant difference between soaking and no soaking. Comparing 5 minutes and 10 minutes soaking no difference are found. This study shows the effect of flow rate on the cleaning performance and it can be concluded that for adequate cleaning of hollow medical instruments the shear stress induced by the flow rate should be taken into account. The results in this study can be used as ground truth to compare to the cleaning performance of different complex geometries with each other. Furthermore, with the method described in this article the effect of more cleaning parameters could be investigated. ...
significant differences in the cleaning performance of flushing with 3.5 L/min compared to lower flow rates is found. Moreover, this study shows that there is a significant difference between soaking and no soaking. Comparing 5 minutes and 10 minutes soaking no difference are found. This study shows the effect of flow rate on the cleaning performance and it can be concluded that for adequate cleaning of hollow medical instruments the shear stress induced by the flow rate should be taken into account. The results in this study can be used as ground truth to compare to the cleaning performance of different complex geometries with each other. Furthermore, with the method described in this article the effect of more cleaning parameters could be investigated. ...
Cleaning is an important factor in the reprocessing of hollow medical instruments. Inadequate cleaning disturbs the disinfection and sterilization process and increases the risk of cross-contamination. An automated washer-disinfector is often used for cleaning medical instruments, by using fluid flow. fluid flow induces shear stress at the wall of medical instruments and is able to detach contamination from the surface. However, there is a lack of studies on the effect of flow rate on the cleaning performance. Also in the ISO standards, no flow requirements can be found to remove contamination. In this study, the relationship between the flow rate and removed mass fraction at different soaking times is investigated to get more insight in the effect of fluid flow on the cleaning performance. The results in this study show that, for smooth tubes with a diameter of 9 mm, the removed mass fraction increases for flow rates up to 7.1 L/min where after the removed mass fraction stagnates. An ANOVA test was performed in combination with a Tukey HSD multiple comparison test to determine significant effects. There is a significant difference in the mass fraction removed, by applying different flow rates (F = 88.24, p = 9.49*10^-33) and different soaking times (F = 15.35, p = 2.8*10^-6), with F as the test statistic from the F-test and p as the p-value. The Tukey HSD test shows significant difference comparing flow rates greater than 5.9 L/min with flow rates smaller or equal to 5.1 L/min. For cleaning with 7.1 L/min, 5.9 L/min or 8.0 L/min no significant differences in the results are found. Furthermore, no
significant differences in the cleaning performance of flushing with 3.5 L/min compared to lower flow rates is found. Moreover, this study shows that there is a significant difference between soaking and no soaking. Comparing 5 minutes and 10 minutes soaking no difference are found. This study shows the effect of flow rate on the cleaning performance and it can be concluded that for adequate cleaning of hollow medical instruments the shear stress induced by the flow rate should be taken into account. The results in this study can be used as ground truth to compare to the cleaning performance of different complex geometries with each other. Furthermore, with the method described in this article the effect of more cleaning parameters could be investigated.
significant differences in the cleaning performance of flushing with 3.5 L/min compared to lower flow rates is found. Moreover, this study shows that there is a significant difference between soaking and no soaking. Comparing 5 minutes and 10 minutes soaking no difference are found. This study shows the effect of flow rate on the cleaning performance and it can be concluded that for adequate cleaning of hollow medical instruments the shear stress induced by the flow rate should be taken into account. The results in this study can be used as ground truth to compare to the cleaning performance of different complex geometries with each other. Furthermore, with the method described in this article the effect of more cleaning parameters could be investigated.
Design of a module for bipolar vessel sealing
The conversion of Electrosurgical to Advanced bipolar power for Low- and Middle-income countries
Master thesis
(2020)
-
Shivani Sinha, Daniel Robertson, Paddy French, Jenny Dankelman, Andre Bossche
According to recent survey [1], about 6 billion people live in Low-and-Middle Income Countries (LMICs) who do not have proper access to safe surgical care. There are several reasons behind this, such as lack of funding to the healthcare department, below par maintenance of the available devices, poor infrastructure and most importantly high cost of the surgical equipment necessary in an operating room. A bipolar vessel sealing system is one of the many devices which is required for laparoscopic surgery and new innovations in the vessel sealing technologies have transformed the ways of electrosurgery as these devices perform surgery in a safe, reliable and efficient way with minimum operating time and reduced blood loss. Unfortunately, these units have been extensively designed and developed for High Income Countries but not so much for LMICs. The department of Medical Instruments & Bio Inspired Technology at TU Delft is currently working on a solution to produce a vessel sealing system which is safe and reliable to be used in LMICs. Electrosurgery is a type of surgery where high frequency alternating current is used to obtain a desired tissue effect like cut, coagulate, desiccate and fulgurate by converting electrical energy into thermal energy. An Electrosurgical unit is a generator which provides energy for many such surgical procedures and is available in every hospital. The aim of this project is to provide an additional module which can be attached to the ESU and generate energy of a bipolar vessel sealing system. The module will have a simple circuit design for easy maintenance and will be made of easily available, replaceable and inexpensive components. This will provide a possible solution to use bipolar vessel sealing in low cost setting. The list of requirements for the circuit of this module is collected from technical details in user manuals and experimental studies for both conventional ESUs and bipolar vessel sealing systems. It also determined the input and output characteristics of the module. The circuit design of the module is based on the block diagram of a common ESU and similar components have been used to establish a connection. The circuit was designed and simulated in a software and the outcomes were matched to the output of a bipolar vessel sealing system already in use (LigaSure vessel sealing system).Further investigation and research are required to make this module functional for clinical applications as the module does not perform all the functions of a bipolar vessel sealing system, but it does fulfil the basic purpose for which such a system is used in electrosurgery.
...
According to recent survey [1], about 6 billion people live in Low-and-Middle Income Countries (LMICs) who do not have proper access to safe surgical care. There are several reasons behind this, such as lack of funding to the healthcare department, below par maintenance of the available devices, poor infrastructure and most importantly high cost of the surgical equipment necessary in an operating room. A bipolar vessel sealing system is one of the many devices which is required for laparoscopic surgery and new innovations in the vessel sealing technologies have transformed the ways of electrosurgery as these devices perform surgery in a safe, reliable and efficient way with minimum operating time and reduced blood loss. Unfortunately, these units have been extensively designed and developed for High Income Countries but not so much for LMICs. The department of Medical Instruments & Bio Inspired Technology at TU Delft is currently working on a solution to produce a vessel sealing system which is safe and reliable to be used in LMICs. Electrosurgery is a type of surgery where high frequency alternating current is used to obtain a desired tissue effect like cut, coagulate, desiccate and fulgurate by converting electrical energy into thermal energy. An Electrosurgical unit is a generator which provides energy for many such surgical procedures and is available in every hospital. The aim of this project is to provide an additional module which can be attached to the ESU and generate energy of a bipolar vessel sealing system. The module will have a simple circuit design for easy maintenance and will be made of easily available, replaceable and inexpensive components. This will provide a possible solution to use bipolar vessel sealing in low cost setting. The list of requirements for the circuit of this module is collected from technical details in user manuals and experimental studies for both conventional ESUs and bipolar vessel sealing systems. It also determined the input and output characteristics of the module. The circuit design of the module is based on the block diagram of a common ESU and similar components have been used to establish a connection. The circuit was designed and simulated in a software and the outcomes were matched to the output of a bipolar vessel sealing system already in use (LigaSure vessel sealing system).Further investigation and research are required to make this module functional for clinical applications as the module does not perform all the functions of a bipolar vessel sealing system, but it does fulfil the basic purpose for which such a system is used in electrosurgery.
Steerable and Reusable Bipolar Vessel Sealer
Design, Development and Validation
A new radical design approach arose from the need to develop a bipolar electrosurgical instrument that is modular and cleanable, thus reusable and therefore suitable for low- and middle-income countries (LMICs). Advanced Bipolar Vessel Sealer (BVS) instruments that are currently on the market cannot be cleaned or maintained well and are therefore most often sold as disposables. Especially in LMICs it is a significant financial burden for hospitals. This possibly leads to the re-use of single-use intended instruments which in turn jeopardizes patient safety. Simultaneously, designing a reusable instrument fits well in the transition to a more circular and sustainable society. To perform advanced laparoscopic surgery with cleanable and affordable electrosurgical instruments, a new design approach is needed. A first phase was initiated by the creation of a cable less steering principle called Shaft Actuated Tip Articulation (SATA) mechanism [6]. Unfortunately, by adding electrically conductive wires to a SATA instrument it loses its modularity and thus cleanability, precisely for which the SATA technology offered a solution in the first place. In addition, there are no non-robotically controlled and reusable BVS instruments with two DOFs available on the market. By being steerable, the user of the instrument is able to deliver a higher quality seal as well as to seal more difficult-to-reach blood vessels and tissue. In this thesis project the goal is to redesign a SATA instrument which sustains bipolar vessel sealing and thus designing a BVS that is easy to clean, easily disinfected and sterilized and which is reusable for a vast amount of surgical procedures. Ideas have been gained by analysing the SATA mechanism and studying commonly used BVS devices. A systematic selection procedure based on the design requirements has resulted in a winning concept for the conduction of electricity through the SATA instrument. For the design of the tip, determining factors were elaborated on, including the construction of the open and close mechanism and the force transmission ratio between the required seal force on the blood vessel or tissue and the necessary tensile force in the core of the instrument. The most critical components of the final model have been identified and evaluated by means of FEM simulations and an experiment. The FEM simulations of the tip components show that the design is satisfactory and that a safety factor of ~1.5 has been achieved. This means that these components do not fail due to normal use and they have a long lifespan as well. In the experiment a flexible nitinol guidewire with Teflon coating was tested for wear by pulling the guidewire through an angled SATA hinge. After some necessary adjustments and additions to the design of the BVS, the results were improved but not optimal. The outcome of this project is a good basis for the BVS design where the steerability has been maintained as well as the modularity and cleanability. The reusability depending on the flexible coating around the core needs to be further investigated and improved.
...
A new radical design approach arose from the need to develop a bipolar electrosurgical instrument that is modular and cleanable, thus reusable and therefore suitable for low- and middle-income countries (LMICs). Advanced Bipolar Vessel Sealer (BVS) instruments that are currently on the market cannot be cleaned or maintained well and are therefore most often sold as disposables. Especially in LMICs it is a significant financial burden for hospitals. This possibly leads to the re-use of single-use intended instruments which in turn jeopardizes patient safety. Simultaneously, designing a reusable instrument fits well in the transition to a more circular and sustainable society. To perform advanced laparoscopic surgery with cleanable and affordable electrosurgical instruments, a new design approach is needed. A first phase was initiated by the creation of a cable less steering principle called Shaft Actuated Tip Articulation (SATA) mechanism [6]. Unfortunately, by adding electrically conductive wires to a SATA instrument it loses its modularity and thus cleanability, precisely for which the SATA technology offered a solution in the first place. In addition, there are no non-robotically controlled and reusable BVS instruments with two DOFs available on the market. By being steerable, the user of the instrument is able to deliver a higher quality seal as well as to seal more difficult-to-reach blood vessels and tissue. In this thesis project the goal is to redesign a SATA instrument which sustains bipolar vessel sealing and thus designing a BVS that is easy to clean, easily disinfected and sterilized and which is reusable for a vast amount of surgical procedures. Ideas have been gained by analysing the SATA mechanism and studying commonly used BVS devices. A systematic selection procedure based on the design requirements has resulted in a winning concept for the conduction of electricity through the SATA instrument. For the design of the tip, determining factors were elaborated on, including the construction of the open and close mechanism and the force transmission ratio between the required seal force on the blood vessel or tissue and the necessary tensile force in the core of the instrument. The most critical components of the final model have been identified and evaluated by means of FEM simulations and an experiment. The FEM simulations of the tip components show that the design is satisfactory and that a safety factor of ~1.5 has been achieved. This means that these components do not fail due to normal use and they have a long lifespan as well. In the experiment a flexible nitinol guidewire with Teflon coating was tested for wear by pulling the guidewire through an angled SATA hinge. After some necessary adjustments and additions to the design of the BVS, the results were improved but not optimal. The outcome of this project is a good basis for the BVS design where the steerability has been maintained as well as the modularity and cleanability. The reusability depending on the flexible coating around the core needs to be further investigated and improved.