Amy Kerdok - Academia.edu (original) (raw)

Papers by Amy Kerdok

Journal of the American Society of Nephrology, Nov 1, 2022

Journal of the American Society of Nephrology, Oct 1, 2020

Proceedings of the Human Factors and Ergonomics Society ... Annual Meeting, Sep 1, 2021

Hemodialysis is a complicated process that comes with many risks to both the user and the patient... more Hemodialysis is a complicated process that comes with many risks to both the user and the patient. The Tablo Hemodialysis System demonstrates how applying user-centered approaches to design could greatly improve device usability, and in turn, user and patient safety. Even with the Covid-19 pandemic creating unexpected hurdles to this approach, Tablo’s sensor-based technology offers a unique solution to ensure that user needs continue to be met.

2018 Design of Medical Devices Conference, Apr 9, 2018

BACKGROUND Minimally invasive surgery (MIS) requires ports to be placed through the body wall in ... more BACKGROUND Minimally invasive surgery (MIS) requires ports to be placed through the body wall in a manner such that instruments can reach a desired area. Limitations of laparoscopic surgery include maintaining triangulation and ergonomics for the surgeon while allowing access to the anatomy with non-wristed instruments [1]. In robotically-assisted MIS, the surgeon does not stand bedside, and they have wristed instruments that the robot manipulates. Limitations of robotically-assisted MIS include range of motion (ROM) limits and decreased spatial awareness, resulting in the potential for interfering robotic components. As a result, port placement varies between laparoscopic and robotically-assisted surgery. Port placement is a critical step for robotically-assisted MIS setup, and, if executed poorly, it will result in a number of difficulties throughout the procedure. These difficulties include, but are not limited to, instrument reach issues due to ROM limits, spar interferences, and unnaturalness of instrumentation due to their position relative to the scope's field of view (FOV). The spar is the most distal link of the patient side cart (PSC) that attaches to the cannula, controlling the insertion axis of the instrument. Naturalness will also be referred to as "anthropomorphicness" as it is related to the human's perception of where one's hands should be relative to one's eyes. Clinical specialty guides (shown in figure 1) are developed by the manufacturer (Intuitive Surgical) empirically with surgeon input, and are validated in cadaveric models [2]. These clinical specialty guides, in combination with personal and peer experience, are used to inform the surgeon's port placement. A "one size fits all" port placement strategy is adequate in theory, however, in practice, optimization to patient's specific needs (i.e. patient habitus) is lacking. The goal of this research was to provide more objective port placement suggestions by approaching the problem through more analytical patientcentric methods.

Toxins

Reliable models of renal failure in large animals are critical to the successful translation of t... more Reliable models of renal failure in large animals are critical to the successful translation of the next generation of renal replacement therapies (RRT) into humans. While models exist for the induction of renal failure, none are optimized for the implantation of devices to the retroperitoneal vasculature. We successfully piloted an embolization-to-implantation protocol enabling the first implant of a silicon nanopore membrane hemodialyzer (SNMHD) in a swine renal failure model. Renal arterial embolization is a non-invasive approach to near-total nephrectomy that preserves retroperitoneal anatomy for device implants. Silicon nanopore membranes (SNM) are efficient blood-compatible membranes that enable novel approaches to RRT. Yucatan minipigs underwent staged bilateral renal arterial embolization to induce renal failure, managed by intermittent hemodialysis. A small-scale arteriovenous SNMHD prototype was implanted into the retroperitoneum. Dialysate catheters were tunneled external...

Journal of Medical Devices-transactions of The Asme, Jul 21, 2014

Lecture Notes in Computer Science, 2004

Mechanical properties of biological tissues are needed for accurate surgical simulation and diagn... more Mechanical properties of biological tissues are needed for accurate surgical simulation and diagnostic purposes. These properties change postmortem due to alterations in both the environmental and physical conditions of the tissue. Despite these known changes, the majority of existing data have been acquired ex vivo due to ease of testing. This study seeks to quantify the effects of testing conditions on the measurements obtained when testing the same tissue in the same locations with two different instruments over time. We will discuss measurements made with indentation probes on whole porcine livers in vivo, ex vivo with a perfusion system that maintains temperature, hydration, and physiologic pressure, ex vivo unperfused, and untreated excised lobes. The data show >50% differences in steady state stiffness between tissues in vivo and unperfused, but only 17% differences between in vivo and perfused tests. Variations also exist in the time-domain and frequency domain responses between all test conditions.

Innovations in Engineering Education: Mechanical Engineering Education, Mechanical Engineering/Mechanical Engineering Technology Department Heads, 2005

Over the past four years, we have redesigned Harvard's introductory mechanical engineering course... more Over the past four years, we have redesigned Harvard's introductory mechanical engineering course to introduce the principles, practices, and pleasures of mechanical engineering in an accessible format. The main goals of the course are to provide experience in the design process, demonstrate the connection between engineering science and design early in the curriculum, and build student enthusiasm for engineering, serving to attract and retain students. Unlike most introductory mechanical engineering courses, we cover strength of materials and machine elements, material usually presented much later in the curriculum, in order to provide tools for the students to quantitatively evaluate their designs. By providing just enough of this background knowledge to allow for analysis of designs, we demonstrate the connection between engineering science and design early in curriculum and motivate in-depth coverage of these topics in later courses.

Journal of Biomechanics, 2006

Accurate characterization of soft tissue material properties is required to enable new computer-a... more Accurate characterization of soft tissue material properties is required to enable new computer-aided medical technologies such as surgical training and planning. The current means of acquiring these properties in the in vivo and ex vivo states is fraught with problems, including limited accessibility and unknown boundary conditions in the former, and unnatural behavior in the latter. This paper presents a new testing method where a whole porcine liver is perfused under physiologic conditions and tested in an ex vivo setting. To characterize the effects of perfusion on the viscoelastic response of liver, indentation devices made force and displacement measurements across four conditions: in vivo, ex vivo perfused, ex vivo post perfused, and in vitro on an excised section. One device imposed cyclic perturbations on the liver's surface, inducing nominal strains up to 5% at frequencies from 0.1 to 200 Hz. The other device measured 300 s of the organ's creep response to applied loads, inducing nominal surface stresses of 6.9-34.7 kPa and nominal strains up to 50%. Results from empirical models indicate that the viscoelastic properties of liver change with perfusion and that two time constants on the order of 1.86 and 51.3 s can characterize the liver under large strains typical of surgical manipulation across time periods up to 300 s. Unperfused conditions were stiffer and more viscous than the in vivo state, resulting in permanent strain deformation with repeated indentations. Conversely, the responses from the ex vivo perfusion condition closely approximated the in vivo response.

ASME 2007 Summer Bioengineering Conference, Jun 20, 2007

Journal of biomechanical engineering, Mar 15, 2011

We describe a modeling methodology intended as a preliminary step in the identification of approp... more We describe a modeling methodology intended as a preliminary step in the identification of appropriate constitutive frameworks for the time-dependent response of biological tissues. The modeling approach comprises a customizable rheological network of viscous and elastic elements governed by user-defined 1D constitutive relationships. The model parameters are identified by iterative nonlinear optimization, minimizing the error between experimental and model-predicted structural (load-displacement) tissue response under a specific mode of deformation. We demonstrate the use of this methodology by determining the minimal rheological arrangement, constitutive relationships, and model parameters for the structural response of various soft tissues, including ex-vivo perfused porcine liver in indentation, ex-vivo porcine brain cortical tissue in indentation, and ex-vivo human cervical tissue in unconfined compression. Our results indicate that the identified rheological configurations provide good agreement with experimental data, including multiple constant strain-rate load/unload tests and stress-relaxation tests. Our experience suggests that the described modeling framework is an efficient tool for exploring a wide array of constitutive relationships and rheological arrangements, which can subsequently serve as a basis for 3D constitutive model development and finite-element implementations. The proposed approach can also be employed as a self-contained tool to obtain simplified 1D phenomenological models of the structural response of biological tissue to single-axis manipulations for applications in haptic technologies.

year physiology, especially those papers emphasizing adaptive and integrative mechanisms. It is p... more year physiology, especially those papers emphasizing adaptive and integrative mechanisms. It is published 12 times a publishes original papers that deal with diverse area of research in applied

INTRODUCTION Mechanical simulation of soft tissue is increasingly important for the development o... more INTRODUCTION Mechanical simulation of soft tissue is increasingly important for the development of new minimally invasive surgical applications. For surgical planning, the prediction of tissue deformation in response to instrument manipulation can improve accuracy of image-guided procedures. For surgical training, simulations permit new surgeons to safely practice a wide variety of procedures. To be effective in these applications, mechanical simulations must be realistic, so that the tissue behaves as in the living organism. This requires accurate in vivo constitutive models for tissues under the large deformations typical of surgical procedures. The complexity of soft tissues makes characterizing their behavior a formidable challenge. Soft tissues exhibit viscoelastic properties, anisotropy, and inhomogeneity [1]. These tissues are drastically altered when no longer perfused, maintained at constant temperature, or bounded by the original surrounding structures as in the commonly t...

Journal of Medical Devices, 2014

Running is a form of locomotion during which active muscles consume metabolic energy to support t... more Running is a form of locomotion during which active muscles consume metabolic energy to support the weight of the runner, and elastic components (tendons, ligaments, muscles, and bones) conserve energy for the runner. In this thesis we studied both the energetics and mechanics of running on surfaces of different stiffness to try and further the understanding of the basic control mechanisms behind animal locomotion. An experimental track with adjustable surface stiffness was designed and built to fit on a level treadmill surface. A force plate positioned beneath the track was used to measure vertical reaction forces. Eight male subjects (mean body mass 74.39 ± 7.12 kg; leg length 0.959 ± 0.049 m, mean ± S.D.) participated in an experiment where they ran at 3.7 m/s over five different surface stiffnesses (75.4, 97.5, 216.8, 454.2, and 945.7 kN/m) on the treadmill. Metabolic, force, and kinematic data were collected. We found that the runner's cost of transport (the amount of energy required to move a unit weight a unit distance) decreased by 12% over the 12-fold change in surface stiffness, and the leg stiffness of the runner increased by 29%. However, the total stiffness of the runner's leg plus the track remained constant as surface stiffness decreased. These results suggest that runners adjust leg stiffness to compensate for changes in surface stiffness while maintaining consistent running dynamics on all surfaces. This thesis could not have been completed without the help of many people. In the wake of my advisor's (Thomas A. McMahon) tragic death, many people came forth to offer assistance of all kinds. Without the support from these people this work would never have been completed. To thank and acknowledge everyone would be impossible, but there are a select few I'd like to recognize whose efforts went above and beyond. I'd first like to thank the Witaker Foundation. The funding I received from them allowed me to be a "free agent" to choose exactly what project interested me without having to worry about much additional funding. Dr. Hugh M. Herr from the Massachusetts Institute of Technology's Leg Laboratory deserves more than a thank you for stepping up to take over the role of my primary research advisor after Dr. McMahon's death. Dr. Herr was an invaluable source of ideas, knowledge, and motivation. Similarly, Dr. Andrew Biewener from Harvard University's Concord Field Station provided me with infinite council and support. The time, space, equipment, and advice he provided made me feel as if I was one of his own graduate students, and I am most appreciative. Other people at the Concord Field station deserve a word of thanks for their assistance in my thesis as well. Mike Williamson was my extremely helpful and diligent assistant throughout my experiments, and Dr. Peter Weyand was not only a subject, but also a source of advice and technical help. Lastly, Seth Wright and Matthew Bellizzi were the technical support and masterminds behind my complicated LabView programs.

2018 Design of Medical Devices Conference, Apr 9, 2018

BACKGROUND Minimally invasive surgery (MIS) requires ports to be placed through the body wall in ... more BACKGROUND Minimally invasive surgery (MIS) requires ports to be placed through the body wall in a manner such that instruments can reach a desired area. Limitations of laparoscopic surgery include maintaining triangulation and ergonomics for the surgeon while allowing access to the anatomy with non-wristed instruments [1]. In robotically-assisted MIS, the surgeon does not stand bedside, and they have wristed instruments that the robot manipulates. Limitations of robotically-assisted MIS include range of motion (ROM) limits and decreased spatial awareness, resulting in the potential for interfering robotic components. As a result, port placement varies between laparoscopic and robotically-assisted surgery. Port placement is a critical step for robotically-assisted MIS setup, and, if executed poorly, it will result in a number of difficulties throughout the procedure. These difficulties include, but are not limited to, instrument reach issues due to ROM limits, spar interferences, and unnaturalness of instrumentation due to their position relative to the scope's field of view (FOV). The spar is the most distal link of the patient side cart (PSC) that attaches to the cannula, controlling the insertion axis of the instrument. Naturalness will also be referred to as "anthropomorphicness" as it is related to the human's perception of where one's hands should be relative to one's eyes. Clinical specialty guides (shown in figure 1) are developed by the manufacturer (Intuitive Surgical) empirically with surgeon input, and are validated in cadaveric models [2]. These clinical specialty guides, in combination with personal and peer experience, are used to inform the surgeon's port placement. A "one size fits all" port placement strategy is adequate in theory, however, in practice, optimization to patient's specific needs (i.e. patient habitus) is lacking. The goal of this research was to provide more objective port placement suggestions by approaching the problem through more analytical patientcentric methods.

Proceedings of the Human Factors and Ergonomics Society Annual Meeting

Hemodialysis is a complicated process that comes with many risks to both the user and the patient... more Hemodialysis is a complicated process that comes with many risks to both the user and the patient. The Tablo Hemodialysis System demonstrates how applying user-centered approaches to design could greatly improve device usability, and in turn, user and patient safety. Even with the Covid-19 pandemic creating unexpected hurdles to this approach, Tablo’s sensor-based technology offers a unique solution to ensure that user needs continue to be met.

Journal of the American Society of Nephrology, Nov 1, 2022

Journal of the American Society of Nephrology, Oct 1, 2020

Proceedings of the Human Factors and Ergonomics Society ... Annual Meeting, Sep 1, 2021

Hemodialysis is a complicated process that comes with many risks to both the user and the patient... more Hemodialysis is a complicated process that comes with many risks to both the user and the patient. The Tablo Hemodialysis System demonstrates how applying user-centered approaches to design could greatly improve device usability, and in turn, user and patient safety. Even with the Covid-19 pandemic creating unexpected hurdles to this approach, Tablo’s sensor-based technology offers a unique solution to ensure that user needs continue to be met.

2018 Design of Medical Devices Conference, Apr 9, 2018

BACKGROUND Minimally invasive surgery (MIS) requires ports to be placed through the body wall in ... more BACKGROUND Minimally invasive surgery (MIS) requires ports to be placed through the body wall in a manner such that instruments can reach a desired area. Limitations of laparoscopic surgery include maintaining triangulation and ergonomics for the surgeon while allowing access to the anatomy with non-wristed instruments [1]. In robotically-assisted MIS, the surgeon does not stand bedside, and they have wristed instruments that the robot manipulates. Limitations of robotically-assisted MIS include range of motion (ROM) limits and decreased spatial awareness, resulting in the potential for interfering robotic components. As a result, port placement varies between laparoscopic and robotically-assisted surgery. Port placement is a critical step for robotically-assisted MIS setup, and, if executed poorly, it will result in a number of difficulties throughout the procedure. These difficulties include, but are not limited to, instrument reach issues due to ROM limits, spar interferences, and unnaturalness of instrumentation due to their position relative to the scope's field of view (FOV). The spar is the most distal link of the patient side cart (PSC) that attaches to the cannula, controlling the insertion axis of the instrument. Naturalness will also be referred to as "anthropomorphicness" as it is related to the human's perception of where one's hands should be relative to one's eyes. Clinical specialty guides (shown in figure 1) are developed by the manufacturer (Intuitive Surgical) empirically with surgeon input, and are validated in cadaveric models [2]. These clinical specialty guides, in combination with personal and peer experience, are used to inform the surgeon's port placement. A "one size fits all" port placement strategy is adequate in theory, however, in practice, optimization to patient's specific needs (i.e. patient habitus) is lacking. The goal of this research was to provide more objective port placement suggestions by approaching the problem through more analytical patientcentric methods.

Toxins

Reliable models of renal failure in large animals are critical to the successful translation of t... more Reliable models of renal failure in large animals are critical to the successful translation of the next generation of renal replacement therapies (RRT) into humans. While models exist for the induction of renal failure, none are optimized for the implantation of devices to the retroperitoneal vasculature. We successfully piloted an embolization-to-implantation protocol enabling the first implant of a silicon nanopore membrane hemodialyzer (SNMHD) in a swine renal failure model. Renal arterial embolization is a non-invasive approach to near-total nephrectomy that preserves retroperitoneal anatomy for device implants. Silicon nanopore membranes (SNM) are efficient blood-compatible membranes that enable novel approaches to RRT. Yucatan minipigs underwent staged bilateral renal arterial embolization to induce renal failure, managed by intermittent hemodialysis. A small-scale arteriovenous SNMHD prototype was implanted into the retroperitoneum. Dialysate catheters were tunneled external...

Journal of Medical Devices-transactions of The Asme, Jul 21, 2014

Lecture Notes in Computer Science, 2004

Mechanical properties of biological tissues are needed for accurate surgical simulation and diagn... more Mechanical properties of biological tissues are needed for accurate surgical simulation and diagnostic purposes. These properties change postmortem due to alterations in both the environmental and physical conditions of the tissue. Despite these known changes, the majority of existing data have been acquired ex vivo due to ease of testing. This study seeks to quantify the effects of testing conditions on the measurements obtained when testing the same tissue in the same locations with two different instruments over time. We will discuss measurements made with indentation probes on whole porcine livers in vivo, ex vivo with a perfusion system that maintains temperature, hydration, and physiologic pressure, ex vivo unperfused, and untreated excised lobes. The data show >50% differences in steady state stiffness between tissues in vivo and unperfused, but only 17% differences between in vivo and perfused tests. Variations also exist in the time-domain and frequency domain responses between all test conditions.

Innovations in Engineering Education: Mechanical Engineering Education, Mechanical Engineering/Mechanical Engineering Technology Department Heads, 2005

Over the past four years, we have redesigned Harvard's introductory mechanical engineering course... more Over the past four years, we have redesigned Harvard's introductory mechanical engineering course to introduce the principles, practices, and pleasures of mechanical engineering in an accessible format. The main goals of the course are to provide experience in the design process, demonstrate the connection between engineering science and design early in the curriculum, and build student enthusiasm for engineering, serving to attract and retain students. Unlike most introductory mechanical engineering courses, we cover strength of materials and machine elements, material usually presented much later in the curriculum, in order to provide tools for the students to quantitatively evaluate their designs. By providing just enough of this background knowledge to allow for analysis of designs, we demonstrate the connection between engineering science and design early in curriculum and motivate in-depth coverage of these topics in later courses.

Journal of Biomechanics, 2006

Accurate characterization of soft tissue material properties is required to enable new computer-a... more Accurate characterization of soft tissue material properties is required to enable new computer-aided medical technologies such as surgical training and planning. The current means of acquiring these properties in the in vivo and ex vivo states is fraught with problems, including limited accessibility and unknown boundary conditions in the former, and unnatural behavior in the latter. This paper presents a new testing method where a whole porcine liver is perfused under physiologic conditions and tested in an ex vivo setting. To characterize the effects of perfusion on the viscoelastic response of liver, indentation devices made force and displacement measurements across four conditions: in vivo, ex vivo perfused, ex vivo post perfused, and in vitro on an excised section. One device imposed cyclic perturbations on the liver's surface, inducing nominal strains up to 5% at frequencies from 0.1 to 200 Hz. The other device measured 300 s of the organ's creep response to applied loads, inducing nominal surface stresses of 6.9-34.7 kPa and nominal strains up to 50%. Results from empirical models indicate that the viscoelastic properties of liver change with perfusion and that two time constants on the order of 1.86 and 51.3 s can characterize the liver under large strains typical of surgical manipulation across time periods up to 300 s. Unperfused conditions were stiffer and more viscous than the in vivo state, resulting in permanent strain deformation with repeated indentations. Conversely, the responses from the ex vivo perfusion condition closely approximated the in vivo response.

ASME 2007 Summer Bioengineering Conference, Jun 20, 2007

Journal of biomechanical engineering, Mar 15, 2011

We describe a modeling methodology intended as a preliminary step in the identification of approp... more We describe a modeling methodology intended as a preliminary step in the identification of appropriate constitutive frameworks for the time-dependent response of biological tissues. The modeling approach comprises a customizable rheological network of viscous and elastic elements governed by user-defined 1D constitutive relationships. The model parameters are identified by iterative nonlinear optimization, minimizing the error between experimental and model-predicted structural (load-displacement) tissue response under a specific mode of deformation. We demonstrate the use of this methodology by determining the minimal rheological arrangement, constitutive relationships, and model parameters for the structural response of various soft tissues, including ex-vivo perfused porcine liver in indentation, ex-vivo porcine brain cortical tissue in indentation, and ex-vivo human cervical tissue in unconfined compression. Our results indicate that the identified rheological configurations provide good agreement with experimental data, including multiple constant strain-rate load/unload tests and stress-relaxation tests. Our experience suggests that the described modeling framework is an efficient tool for exploring a wide array of constitutive relationships and rheological arrangements, which can subsequently serve as a basis for 3D constitutive model development and finite-element implementations. The proposed approach can also be employed as a self-contained tool to obtain simplified 1D phenomenological models of the structural response of biological tissue to single-axis manipulations for applications in haptic technologies.

year physiology, especially those papers emphasizing adaptive and integrative mechanisms. It is p... more year physiology, especially those papers emphasizing adaptive and integrative mechanisms. It is published 12 times a publishes original papers that deal with diverse area of research in applied

INTRODUCTION Mechanical simulation of soft tissue is increasingly important for the development o... more INTRODUCTION Mechanical simulation of soft tissue is increasingly important for the development of new minimally invasive surgical applications. For surgical planning, the prediction of tissue deformation in response to instrument manipulation can improve accuracy of image-guided procedures. For surgical training, simulations permit new surgeons to safely practice a wide variety of procedures. To be effective in these applications, mechanical simulations must be realistic, so that the tissue behaves as in the living organism. This requires accurate in vivo constitutive models for tissues under the large deformations typical of surgical procedures. The complexity of soft tissues makes characterizing their behavior a formidable challenge. Soft tissues exhibit viscoelastic properties, anisotropy, and inhomogeneity [1]. These tissues are drastically altered when no longer perfused, maintained at constant temperature, or bounded by the original surrounding structures as in the commonly t...

Journal of Medical Devices, 2014

Running is a form of locomotion during which active muscles consume metabolic energy to support t... more Running is a form of locomotion during which active muscles consume metabolic energy to support the weight of the runner, and elastic components (tendons, ligaments, muscles, and bones) conserve energy for the runner. In this thesis we studied both the energetics and mechanics of running on surfaces of different stiffness to try and further the understanding of the basic control mechanisms behind animal locomotion. An experimental track with adjustable surface stiffness was designed and built to fit on a level treadmill surface. A force plate positioned beneath the track was used to measure vertical reaction forces. Eight male subjects (mean body mass 74.39 ± 7.12 kg; leg length 0.959 ± 0.049 m, mean ± S.D.) participated in an experiment where they ran at 3.7 m/s over five different surface stiffnesses (75.4, 97.5, 216.8, 454.2, and 945.7 kN/m) on the treadmill. Metabolic, force, and kinematic data were collected. We found that the runner's cost of transport (the amount of energy required to move a unit weight a unit distance) decreased by 12% over the 12-fold change in surface stiffness, and the leg stiffness of the runner increased by 29%. However, the total stiffness of the runner's leg plus the track remained constant as surface stiffness decreased. These results suggest that runners adjust leg stiffness to compensate for changes in surface stiffness while maintaining consistent running dynamics on all surfaces. This thesis could not have been completed without the help of many people. In the wake of my advisor's (Thomas A. McMahon) tragic death, many people came forth to offer assistance of all kinds. Without the support from these people this work would never have been completed. To thank and acknowledge everyone would be impossible, but there are a select few I'd like to recognize whose efforts went above and beyond. I'd first like to thank the Witaker Foundation. The funding I received from them allowed me to be a "free agent" to choose exactly what project interested me without having to worry about much additional funding. Dr. Hugh M. Herr from the Massachusetts Institute of Technology's Leg Laboratory deserves more than a thank you for stepping up to take over the role of my primary research advisor after Dr. McMahon's death. Dr. Herr was an invaluable source of ideas, knowledge, and motivation. Similarly, Dr. Andrew Biewener from Harvard University's Concord Field Station provided me with infinite council and support. The time, space, equipment, and advice he provided made me feel as if I was one of his own graduate students, and I am most appreciative. Other people at the Concord Field station deserve a word of thanks for their assistance in my thesis as well. Mike Williamson was my extremely helpful and diligent assistant throughout my experiments, and Dr. Peter Weyand was not only a subject, but also a source of advice and technical help. Lastly, Seth Wright and Matthew Bellizzi were the technical support and masterminds behind my complicated LabView programs.

2018 Design of Medical Devices Conference, Apr 9, 2018

BACKGROUND Minimally invasive surgery (MIS) requires ports to be placed through the body wall in ... more BACKGROUND Minimally invasive surgery (MIS) requires ports to be placed through the body wall in a manner such that instruments can reach a desired area. Limitations of laparoscopic surgery include maintaining triangulation and ergonomics for the surgeon while allowing access to the anatomy with non-wristed instruments [1]. In robotically-assisted MIS, the surgeon does not stand bedside, and they have wristed instruments that the robot manipulates. Limitations of robotically-assisted MIS include range of motion (ROM) limits and decreased spatial awareness, resulting in the potential for interfering robotic components. As a result, port placement varies between laparoscopic and robotically-assisted surgery. Port placement is a critical step for robotically-assisted MIS setup, and, if executed poorly, it will result in a number of difficulties throughout the procedure. These difficulties include, but are not limited to, instrument reach issues due to ROM limits, spar interferences, and unnaturalness of instrumentation due to their position relative to the scope's field of view (FOV). The spar is the most distal link of the patient side cart (PSC) that attaches to the cannula, controlling the insertion axis of the instrument. Naturalness will also be referred to as "anthropomorphicness" as it is related to the human's perception of where one's hands should be relative to one's eyes. Clinical specialty guides (shown in figure 1) are developed by the manufacturer (Intuitive Surgical) empirically with surgeon input, and are validated in cadaveric models [2]. These clinical specialty guides, in combination with personal and peer experience, are used to inform the surgeon's port placement. A "one size fits all" port placement strategy is adequate in theory, however, in practice, optimization to patient's specific needs (i.e. patient habitus) is lacking. The goal of this research was to provide more objective port placement suggestions by approaching the problem through more analytical patientcentric methods.

Proceedings of the Human Factors and Ergonomics Society Annual Meeting

Hemodialysis is a complicated process that comes with many risks to both the user and the patient... more Hemodialysis is a complicated process that comes with many risks to both the user and the patient. The Tablo Hemodialysis System demonstrates how applying user-centered approaches to design could greatly improve device usability, and in turn, user and patient safety. Even with the Covid-19 pandemic creating unexpected hurdles to this approach, Tablo’s sensor-based technology offers a unique solution to ensure that user needs continue to be met.