Paul L. Briant, J. Bischoff, M. Dharia, Franck Le Navéaux, Xuemei Li, Sanjeev M. Kulkarni, Danny Levine, David Ramos, Payman Afshari
Evaluating the credibility of computational models used in medical device development is increasingly important as medical devices become more complex and modeling takes on a more critical role in the device development process. While bench-testing based comparisons are common for assessing model credibility and have many advantages, such as control over test specimens and the ability to quantify outputs, the credibility assessments performed with bench tests often do not evaluate the clinical relevance of key aspects of model form (such as boundary conditions, constitutive models/properties, and geometries) selected when simulating in vivo conditions. Real-world data (outcomes data generated through clinical use of a device) offer an opportunity to assess the applicability and clinical relevance of a computational model. Although real-world data are frequently less controlled and more qualitative than benchtop data, real-world data are often a direct assessment of a particular clinical complication and therefore of high clinical relevance. Further, real-world data have the potential to reveal failure modes not previously identified in pre-clinical failure modes analysis, thereby motivating testing advancements. To review the use of clinical data in medical device modeling, this paper presents a series of examples related to tibial tray fracture that incorporate varying levels of benchtop data and real world data when evaluating model credibility. The merits and drawbacks of the credibility assessment for each example are discussed in order to provide practical and actionable guidance on the use of real world data for establishing and demonstrating model credibility.
{"title":"Use of Real-World Data for Enhancing Model Credibility: Applications to Medical Device Development","authors":"Paul L. Briant, J. Bischoff, M. Dharia, Franck Le Navéaux, Xuemei Li, Sanjeev M. Kulkarni, Danny Levine, David Ramos, Payman Afshari","doi":"10.1115/1.4053888","DOIUrl":"https://doi.org/10.1115/1.4053888","url":null,"abstract":"\u0000 Evaluating the credibility of computational models used in medical device development is increasingly important as medical devices become more complex and modeling takes on a more critical role in the device development process. While bench-testing based comparisons are common for assessing model credibility and have many advantages, such as control over test specimens and the ability to quantify outputs, the credibility assessments performed with bench tests often do not evaluate the clinical relevance of key aspects of model form (such as boundary conditions, constitutive models/properties, and geometries) selected when simulating in vivo conditions.\u0000 Real-world data (outcomes data generated through clinical use of a device) offer an opportunity to assess the applicability and clinical relevance of a computational model. Although real-world data are frequently less controlled and more qualitative than benchtop data, real-world data are often a direct assessment of a particular clinical complication and therefore of high clinical relevance. Further, real-world data have the potential to reveal failure modes not previously identified in pre-clinical failure modes analysis, thereby motivating testing advancements. To review the use of clinical data in medical device modeling, this paper presents a series of examples related to tibial tray fracture that incorporate varying levels of benchtop data and real world data when evaluating model credibility. The merits and drawbacks of the credibility assessment for each example are discussed in order to provide practical and actionable guidance on the use of real world data for establishing and demonstrating model credibility.","PeriodicalId":49305,"journal":{"name":"Journal of Medical Devices-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2022-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48066375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
David S. Kirn, William F. Whitman, Richard D. Hisel, J. Price
Background: Tube patency is essential for patients who receive enteral nutrition via a small bore naso-enteral feeding tube. Formation of a clog within these tubes interrupts and delays delivery of nutrition. Unfortunately, current tubes are prone to clogging. A small-bore naso-enteral feeding tube that gradually increases in diameter over its length could mitigate the risk of clog formation. Methods: Small-bore feeding tubes that increase in diameter over their length, were evaluated relative to current (constant diameter) tubes to determine if a tapered tube design could reduce the pressure required to clear an established clog in benchtop testing at pressures representative of those achieved safely in the clinical environment. Results: Incorporating a tapered design into an 8F nasal feeding tube significantly reduced the pressure to expel an established clog by 62% (p < 0.05; 258.6 kPa vs. 710.8 kPa, respectively). Conclusion: When compared to constant diameter tubes with the same proximal outside diameter, a tapered tube design permits clearance of an established clog at lower pressure.
{"title":"Analysis of a Novel Nasoenteral Tube Design","authors":"David S. Kirn, William F. Whitman, Richard D. Hisel, J. Price","doi":"10.1115/1.4053876","DOIUrl":"https://doi.org/10.1115/1.4053876","url":null,"abstract":"\u0000 Background: Tube patency is essential for patients who receive enteral nutrition via a small bore naso-enteral feeding tube. Formation of a clog within these tubes interrupts and delays delivery of nutrition. Unfortunately, current tubes are prone to clogging. A small-bore naso-enteral feeding tube that gradually increases in diameter over its length could mitigate the risk of clog formation.\u0000 Methods: Small-bore feeding tubes that increase in diameter over their length, were evaluated relative to current (constant diameter) tubes to determine if a tapered tube design could reduce the pressure required to clear an established clog in benchtop testing at pressures representative of those achieved safely in the clinical environment.\u0000 Results: Incorporating a tapered design into an 8F nasal feeding tube significantly reduced the pressure to expel an established clog by 62% (p < 0.05; 258.6 kPa vs. 710.8 kPa, respectively).\u0000 Conclusion: When compared to constant diameter tubes with the same proximal outside diameter, a tapered tube design permits clearance of an established clog at lower pressure.","PeriodicalId":49305,"journal":{"name":"Journal of Medical Devices-Transactions of the Asme","volume":"1 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2022-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41565019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents the design, analysis, and fabrication of a capacitive-based three-axis force sensor as the building block of a wearable sensing system to directly measure all the components of three-dimensional (3D) ground reaction forces (3D GRFs) during walking. The proposed sensor is low-cost and easy to fabricate with high accuracy, which promotes its accessibility and usability for gait analysis in clinical and research settings. The sensor is comprised of only three parallel capacitors that enable three-axial force measurement while significantly reducing the complexity of fabrication and maintenance prevalent in three-axis force sensors. Comprehensive experiments were conducted to rigorously quantify different aspects of the sensor's performance. The static and dynamic errors along the three axes are less than 2.28%, which is well within the acceptable range for the intended application. The force sensor can decouple three-axial forces with a cross-sensitivity of less than 2%. The developed sensor also demonstrates desirable repeatability and hysteresis behaviors with almost no drift over long periods of usage.
{"title":"A Low-Cost Three-Axis Force Sensor for Wearable Gait Analysis Systems","authors":"Md Shafiqur Rahman, B. Hejrati","doi":"10.1115/1.4053725","DOIUrl":"https://doi.org/10.1115/1.4053725","url":null,"abstract":"\u0000 This paper presents the design, analysis, and fabrication of a capacitive-based three-axis force sensor as the building block of a wearable sensing system to directly measure all the components of three-dimensional (3D) ground reaction forces (3D GRFs) during walking. The proposed sensor is low-cost and easy to fabricate with high accuracy, which promotes its accessibility and usability for gait analysis in clinical and research settings. The sensor is comprised of only three parallel capacitors that enable three-axial force measurement while significantly reducing the complexity of fabrication and maintenance prevalent in three-axis force sensors. Comprehensive experiments were conducted to rigorously quantify different aspects of the sensor's performance. The static and dynamic errors along the three axes are less than 2.28%, which is well within the acceptable range for the intended application. The force sensor can decouple three-axial forces with a cross-sensitivity of less than 2%. The developed sensor also demonstrates desirable repeatability and hysteresis behaviors with almost no drift over long periods of usage.","PeriodicalId":49305,"journal":{"name":"Journal of Medical Devices-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2022-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44888645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Risk assessment is a critical step in the roadmap of medical device development. Failure modes, effects and criticality analysis is a common approach based on declarative prior information that proved beneficial in the risk assessment of well established processes. But at early steps of development when innovative materials or technologies are embedded, the lack of experience on those innovations introduces too much subjectivity in FMECA for a robust risk assessment. Since mid-2000, the Quality-by-Design guideline has been proposed within the pharmaceutical industry as a proactive engineering approach of drug development. This paradigm enables a data-driven risk assessment throughout the development workflow, which completes risk assessment provided by FMECA. Nevertheless, its implementation guide is unclear and not flexible enough to be efficiently applied to the development of medical devices. To address this issue, a new QbD paradigm indexed on the technological readiness level of the innovative product is proposed. It covers the development of medical devices throughout the whole preclinical phase and is composed of at least nine learning cycles. The first part of this medical device QbD layout, composed of three consecutive risk assessment cycles, is evaluated through a real study case with the objective to demonstrate the proof of concept of a photobleaching controller in photodynamic therapy. Beyond this experimental result, this application has confirmed practical ability of the iQbD approach to complete FMECA and to provide an alternative solution to risk assessment when prior knowledge on the technological innovation is not available.
{"title":"iQbD: a TRL-indexed Quality-by-Design Paradigm for Medical Device Engineering","authors":"T. Bastogne","doi":"10.1115/1.4053721","DOIUrl":"https://doi.org/10.1115/1.4053721","url":null,"abstract":"\u0000 Risk assessment is a critical step in the roadmap of medical device development. Failure modes, effects and criticality analysis is a common approach based on declarative prior information that proved beneficial in the risk assessment of well established processes. But at early steps of development when innovative materials or technologies are embedded, the lack of experience on those innovations introduces too much subjectivity in FMECA for a robust risk assessment. Since mid-2000, the Quality-by-Design guideline has been proposed within the pharmaceutical industry as a proactive engineering approach of drug development. This paradigm enables a data-driven risk assessment throughout the development workflow, which completes risk assessment provided by FMECA. Nevertheless, its implementation guide is unclear and not flexible enough to be efficiently applied to the development of medical devices. To address this issue, a new QbD paradigm indexed on the technological readiness level of the innovative product is proposed. It covers the development of medical devices throughout the whole preclinical phase and is composed of at least nine learning cycles. The first part of this medical device QbD layout, composed of three consecutive risk assessment cycles, is evaluated through a real study case with the objective to demonstrate the proof of concept of a photobleaching controller in photodynamic therapy. Beyond this experimental result, this application has confirmed practical ability of the iQbD approach to complete FMECA and to provide an alternative solution to risk assessment when prior knowledge on the technological innovation is not available.","PeriodicalId":49305,"journal":{"name":"Journal of Medical Devices-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49177481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
After a median sternotomy, the sternal bone has to be refixated using implants such as wires, plates or clamps. However, there is still a lack of specifically applicable test methods to investigate the mechanical safety and effectiveness of such implant systems. The aim of this study was to develop a new test method that replicates the in vivo loads acting on the sternum and that is applicable to all types of sternal closure systems. Based on the scientific literature a setup was developed that incorporates the physiological loads acting on the sternum during breathing (91 N) and coughing (328 N). These loads are applied to a sternum replicate at 5 Hz for approximately 1.8 million cycles. This cycle number is assumed to represent the healing period. For validation, the new method was applied to two different sternal closure systems: a PEEK clamp system and wires. The new test method proved to be easily applicable. The validation tests with the two sternal closure systems showed reasonable and reproducible results regarding all outcome parameters. The pre-tension exerted by the implants significantly differed between the two implant groups and decreased after the first coughing cycles. The fracture gap separation during breathing also significantly different between the two test groups but it was similar during coughing. No implant failed. Using this new test method it is possible to compare sternal closure systems under reproducible conditions and interpret their mechanical characteristics regarding their in vivo safety and effectiveness.
{"title":"Development and Validation of a Physiological Testing Method for Sternal Closure Systems","authors":"Annette Kienle, Nadine Renner, Constanze Bischoff","doi":"10.1115/1.4053687","DOIUrl":"https://doi.org/10.1115/1.4053687","url":null,"abstract":"\u0000 After a median sternotomy, the sternal bone has to be refixated using implants such as wires, plates or clamps. However, there is still a lack of specifically applicable test methods to investigate the mechanical safety and effectiveness of such implant systems. The aim of this study was to develop a new test method that replicates the in vivo loads acting on the sternum and that is applicable to all types of sternal closure systems.\u0000 Based on the scientific literature a setup was developed that incorporates the physiological loads acting on the sternum during breathing (91 N) and coughing (328 N). These loads are applied to a sternum replicate at 5 Hz for approximately 1.8 million cycles. This cycle number is assumed to represent the healing period. For validation, the new method was applied to two different sternal closure systems: a PEEK clamp system and wires.\u0000 The new test method proved to be easily applicable. The validation tests with the two sternal closure systems showed reasonable and reproducible results regarding all outcome parameters. The pre-tension exerted by the implants significantly differed between the two implant groups and decreased after the first coughing cycles. The fracture gap separation during breathing also significantly different between the two test groups but it was similar during coughing. No implant failed.\u0000 Using this new test method it is possible to compare sternal closure systems under reproducible conditions and interpret their mechanical characteristics regarding their in vivo safety and effectiveness.","PeriodicalId":49305,"journal":{"name":"Journal of Medical Devices-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2022-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46816216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. P. Little, D. Green, M. Izatt, Gregory Moloney, G. Askin
Optimal patient positioning for spine surgery is vital for surgical success and the minimisation of complications intra-/post-operatively. In patients with complex co-morbidities, commercially available surgical positioning equipment is inadequate. To overcome this, a novel method was developed to create custom-fit patient-specific theatre mattresses for patients undergoing spine surgery. An innovative digital workflow involving 3D surface scanning, 3D simulation and computer aided design was developed to manufacture customised theatre supports with patient-specific requirements. These supports offered the surgeon an enhanced ability to relieve load bearing on prominent anatomical features or where desired, to tailor the support surface to the patient's anatomy for lengthy surgery. The bespoke theatre mattress was evaluated by whether the support resulted in a complication-free surgery. Using this new workflow, case examples for two patients with complex co-morbidities were described. The spine surgeon and anaesthetist reported the patient-specific custom mattresses were fit as per the required design, provided sufficient clearance around anatomical prominences and areas that required to be unloaded, had sufficient clearance for the anaesthetic method and cannulation, provided excellent surgical access and stability during surgery, and postoperatively no soft tissue overload over bony prominence and implanted devices. Positive patient outcomes after successful lengthy surgical interventions were associated with these patient-specific, contoured mattress supports. Future projects will seek to utilise this technology for other types of surgeries and intra-operative positioning requirements, and for a broader demographic of patients in both the paediatric and adult setting.
{"title":"Patient-Customised Theatre Mattress Supports for Spinal Surgery: A Pilot Study Presenting a Novel Engineering Virtual Design and Manufacturing Technique","authors":"J. P. Little, D. Green, M. Izatt, Gregory Moloney, G. Askin","doi":"10.1115/1.4053604","DOIUrl":"https://doi.org/10.1115/1.4053604","url":null,"abstract":"\u0000 Optimal patient positioning for spine surgery is vital for surgical success and the minimisation of complications intra-/post-operatively. In patients with complex co-morbidities, commercially available surgical positioning equipment is inadequate. To overcome this, a novel method was developed to create custom-fit patient-specific theatre mattresses for patients undergoing spine surgery. An innovative digital workflow involving 3D surface scanning, 3D simulation and computer aided design was developed to manufacture customised theatre supports with patient-specific requirements. These supports offered the surgeon an enhanced ability to relieve load bearing on prominent anatomical features or where desired, to tailor the support surface to the patient's anatomy for lengthy surgery. The bespoke theatre mattress was evaluated by whether the support resulted in a complication-free surgery. Using this new workflow, case examples for two patients with complex co-morbidities were described. The spine surgeon and anaesthetist reported the patient-specific custom mattresses were fit as per the required design, provided sufficient clearance around anatomical prominences and areas that required to be unloaded, had sufficient clearance for the anaesthetic method and cannulation, provided excellent surgical access and stability during surgery, and postoperatively no soft tissue overload over bony prominence and implanted devices. Positive patient outcomes after successful lengthy surgical interventions were associated with these patient-specific, contoured mattress supports. Future projects will seek to utilise this technology for other types of surgeries and intra-operative positioning requirements, and for a broader demographic of patients in both the paediatric and adult setting.","PeriodicalId":49305,"journal":{"name":"Journal of Medical Devices-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2022-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44709517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alexander B. Ambrose, Joshua F. Detelich, M. Weinmann, F. Hammond
Critical care patients who experience symptoms of acute respiratory distress syndrome are commonly placed on mechanical ventilators to increase the oxygen provided to their pulmonary systems and monitor their condition. With the pulmonary inflammation typically accompanying ARDS, patients can experience lower ventilation-perfusion ratios resulting in lower blood oxygenation. In these cases, patients are typically rotated into a prone position to facilitate improved blood flow to portions of the lung that were not previously participating in the gas exchange process. However, proning a patient increases the risk of complications, requires up to seven hospital staff members to carry out, and does not guarantee an improvement in the patient's condition. The low-cost vest presented here was designed to reproduce the effects of proning while also requiring less hospital staff than the proning process. Additionally, the V/Q Vest helps hospital staff predict whether patients would respond well to a proning treatment. A pilot study was conducted on nine patients with ARDS from Coronavirus disease 2019 (COVID-19). The average increase in oxygenation with the V/Q Vest treatment for all patients was 19.7 ± 38.1%. Six of the nine patients responded positively to the V/Q Vest treatment, exhibiting increased oxygenation. The V/Q Vest also helped hospital staff predict that three of the five patients that were proned would experience an increase in oxygenation. An increase in oxygenation resulting from V/Q Vest treatment exceeded that of the proning treatment in two of these five proned patients.
{"title":"Evaluation of a Pneumatic Vest to Treat Symptoms of ARDS Caused by COVID-19","authors":"Alexander B. Ambrose, Joshua F. Detelich, M. Weinmann, F. Hammond","doi":"10.1115/1.4053387","DOIUrl":"https://doi.org/10.1115/1.4053387","url":null,"abstract":"\u0000 Critical care patients who experience symptoms of acute respiratory distress syndrome are commonly placed on mechanical ventilators to increase the oxygen provided to their pulmonary systems and monitor their condition. With the pulmonary inflammation typically accompanying ARDS, patients can experience lower ventilation-perfusion ratios resulting in lower blood oxygenation. In these cases, patients are typically rotated into a prone position to facilitate improved blood flow to portions of the lung that were not previously participating in the gas exchange process. However, proning a patient increases the risk of complications, requires up to seven hospital staff members to carry out, and does not guarantee an improvement in the patient's condition. The low-cost vest presented here was designed to reproduce the effects of proning while also requiring less hospital staff than the proning process. Additionally, the V/Q Vest helps hospital staff predict whether patients would respond well to a proning treatment. A pilot study was conducted on nine patients with ARDS from Coronavirus disease 2019 (COVID-19). The average increase in oxygenation with the V/Q Vest treatment for all patients was 19.7 ± 38.1%. Six of the nine patients responded positively to the V/Q Vest treatment, exhibiting increased oxygenation. The V/Q Vest also helped hospital staff predict that three of the five patients that were proned would experience an increase in oxygenation. An increase in oxygenation resulting from V/Q Vest treatment exceeded that of the proning treatment in two of these five proned patients.","PeriodicalId":49305,"journal":{"name":"Journal of Medical Devices-Transactions of the Asme","volume":"1 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63503388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Needle insertion is a common procedure in percutaneous puncture. A motion planner for a steerable needle that considers the risk level of the path in anatomical environment and the actual deflection of clinical needle is necessary. A novel preoperative motion planner for a steerable needle controlled by robot is proposed. Our method utilizes sampling-based planner to compute candidate path in the reachable region, the path solutions are optimized by calculating the cost of a path based on a cost map. The cost-map, which is built based on repulsive field theory from CT image, encodes the information of the obstacle locations and the criticality of the anatomical environment. The empirical formula that can predict needle trajectory is obtained by insertion experiments. Experiments shown that positioning error in gelatin phantom under the guidance of our planner is less than 1.1mm. Comparing with the straight-line insertion method, the positioning error was reduced by 80%. The results indicate that the motion planner has the potential to provide effective guidance for robot-assisted puncture surgery while enhancing the position precision and patient safety.
{"title":"Preoperative Motion Planner for Steerable Needles Using Cost Map Based on Repulsive Field and Empirical Model of Needle Deflection","authors":"Shan Jiang, Bowen Jiang, Peina Fang, Zhiyong Yang","doi":"10.1115/1.4053285","DOIUrl":"https://doi.org/10.1115/1.4053285","url":null,"abstract":"\u0000 Needle insertion is a common procedure in percutaneous puncture. A motion planner for a steerable needle that considers the risk level of the path in anatomical environment and the actual deflection of clinical needle is necessary. A novel preoperative motion planner for a steerable needle controlled by robot is proposed. Our method utilizes sampling-based planner to compute candidate path in the reachable region, the path solutions are optimized by calculating the cost of a path based on a cost map. The cost-map, which is built based on repulsive field theory from CT image, encodes the information of the obstacle locations and the criticality of the anatomical environment. The empirical formula that can predict needle trajectory is obtained by insertion experiments. Experiments shown that positioning error in gelatin phantom under the guidance of our planner is less than 1.1mm. Comparing with the straight-line insertion method, the positioning error was reduced by 80%. The results indicate that the motion planner has the potential to provide effective guidance for robot-assisted puncture surgery while enhancing the position precision and patient safety.","PeriodicalId":49305,"journal":{"name":"Journal of Medical Devices-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41636267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Toby Elery, Emma Reznick, Staci M. Shearin, Karen J. McCain, R. Gregg
This paper presents the novel design of a Multi-Degree-Of-Freedom joint (M-DOF) for an Ankle-Foot Orthosis (AFO) that aims to improve upon the commercially available Double Action Joint (DAJ). The M-DOF is designed to maintain the functionality of the DAJ, while increasing dorsiflexion stiffness and introducing inversion/eversion. This increase in range of motion is designed to produce greater engagement from lower limb muscles during gait. The M-DOF was experimentally validated with one able-bodied and one stroke subject. Across walking speeds, the M-DOF AFO minimally affected the able-bodied subject's joint kinematics. The stroke subject's ankle dorsiflexion/plantarflexion and knee flexion were not heavily altered when wearing the M-DOF AFO, compared to the DAJ AFO. The new DOF allowed by the M-DOF AFO increased the inversion/eversion of the ankle by ~3°, without introducing any new compensations compared to their gait with the DAJ AFO.
{"title":"Design and Initial Validation of a Multiple Degree-of-Freedom Joint for an Ankle-Foot Orthosis","authors":"Toby Elery, Emma Reznick, Staci M. Shearin, Karen J. McCain, R. Gregg","doi":"10.1115/1.4053200","DOIUrl":"https://doi.org/10.1115/1.4053200","url":null,"abstract":"\u0000 This paper presents the novel design of a Multi-Degree-Of-Freedom joint (M-DOF) for an Ankle-Foot Orthosis (AFO) that aims to improve upon the commercially available Double Action Joint (DAJ). The M-DOF is designed to maintain the functionality of the DAJ, while increasing dorsiflexion stiffness and introducing inversion/eversion. This increase in range of motion is designed to produce greater engagement from lower limb muscles during gait. The M-DOF was experimentally validated with one able-bodied and one stroke subject. Across walking speeds, the M-DOF AFO minimally affected the able-bodied subject's joint kinematics. The stroke subject's ankle dorsiflexion/plantarflexion and knee flexion were not heavily altered when wearing the M-DOF AFO, compared to the DAJ AFO. The new DOF allowed by the M-DOF AFO increased the inversion/eversion of the ankle by ~3°, without introducing any new compensations compared to their gait with the DAJ AFO.","PeriodicalId":49305,"journal":{"name":"Journal of Medical Devices-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42563413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Justin Brooks, C. Feltch, J. Lam, C. Earley, R. Robucci, Sanjay Agarwal, Nilanjan Banerjee
Several sleep disorders are characterized by periodic leg movements during sleep including Restless Leg Syndrome, and can indicate disrupted sleep in otherwise healthy individuals. Current technologies to measure periodic leg movements during sleep are limited. Polysomnography and some home sleep tests use surface electromyography to measure electrical activity from the anterior tibilias muscle. Actigraphy uses 3-axis accelerometers to measure movement of the ankle. Electromyography misses periodic leg movements that involve other leg muscles and is obtrusive because of the wires needed to carry the signal. Actigraphy based devices require large amplitude movements of the ankle to detect leg movements (missing the significant number of more subtle leg movements) and can be worn in multiple configurations precluding precision measurement. These limitations have contributed to their lack of adoption as a standard of care for several sleep disorders. In this study, we develop the RestEaze sleep assessment tool as an ankle-worn wearable device that combines capacitive sensors and a 6-axis inertial measurement unit to precisely measure periodic leg movements during sleep. This unique combination of sensors and the form-factor of the device addresses current limitations of periodic leg movements during sleep measurement techniques. Pilot data collected shows high correlation with polysomnography across a heterogeneous participant sample and high usability ratings. RestEaze shows promise in providing ecologically valid, longitudinal measures of leg movements that will be useful for clinicians, researchers, and patients to better understand sleep.
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