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Emil H Schemitsch - One of the best experts on this subject based on the ideXlab platform.
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the effect of the Registration Process error on component alignment during imageless computer navigation for knee arthroplasty a cadaveric study
Orthopaedic Proceedings, 2018Co-Authors: Joseph Pagkalos, Edward T Davis, P Gallie, K Macgroarty, James P Waddell, Emil H SchemitschAbstract:Implant alignment in knee arthroplasty has been identified as critical factor for a successful outcome. Human error during the Registration Process for imageless computer navigation knee arthroplasty directly affects component alignment. This cadaveric study aims to define the error in the Registration of the landmarks and the resulting error in component alignment.Five fresh frozen cadaveric limbs including the hemipelvis were used for the study. Five surgeons performed the Registration Process via a medial parapatellar approach five times. In order to identify the gold standard point, the soft tissues were stripped and the Registration was repeated by the senior author. Errors are presented as mm or degrees from the gold standard Registration.The error range in the Registration of the femoral centre in the coronal plane was 6.5mm laterally to 5.0mm medially (mean: −0.1, SD: 2.7). This resulted in a mechanical axis error of 5.2 degrees valgus to 2.9 degrees varus (mean: 0.1, SD: 1.1). In the sagittal pla...
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a comparison of Registration errors with imageless computer navigation during mis total knee arthroplasty versus standard incision total knee arthroplasty a cadaveric study
Computer Aided Surgery, 2015Co-Authors: Edward T Davis, Joseph Pagkalos, P Gallie, K Macgroarty, James P Waddell, Emil H SchemitschAbstract:AbstractOptimal component alignment in total knee arthroplasty has been associated with better functional outcome as well as improved implant longevity. The ability to align components optimally during minimally invasive (MIS) total knee replacement (TKR) has been a cause of concern. Computer navigation is a useful aid in achieving the desired alignment although it is limited by the error during the manual Registration of landmarks. Our study aims to compare the Registration Process error between a standard and a MIS surgical approach. We hypothesized that performing the Registration error via an MIS approach would increase the Registration Process error. Five fresh frozen lower limbs were routinely prepared and draped. The Registration Process was performed through an MIS approach. This was then extended to the standard approach and the Registration was performed again. Two surgeons performed the Registration Process five times with each approach. Performing the Registration Process through the MIS appro...
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defining the errors in the Registration Process during imageless computer navigation in total knee arthroplasty a cadaveric study
Journal of Arthroplasty, 2014Co-Authors: Edward T Davis, Joseph Pagkalos, P Gallie, K Macgroarty, James P Waddell, Emil H SchemitschAbstract:Computer assisted arthroplasty was introduced as a means to optimally align implants in order to improve function and longevity. The error during the manual Registration of landmarks and its effect on component alignment was investigated in this study. Five fresh frozen lower limbs were used and the Registration Process was performed five times by five surgeons. The error range of the mechanical axis of the femur in the coronal plane was 5.2 degrees of valgus to 2.9 degrees of varus whilst the transepicondylar axis error was 11.1 degrees of external to 6.3 of internal rotation. Those figures suggest that the Registration error alone can have a significant effect on the alignment of the implant.
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the effect of the Registration Process error on component alignment during imageless computer navigation for knee arthroplasty a cadaveric study
Journal of Bone and Joint Surgery-british Volume, 2013Co-Authors: Joseph Pagkalos, Edward T Davis, P Gallie, K Macgroarty, James P Waddell, Emil H SchemitschAbstract:Implant alignment in knee arthroplasty has been identified as critical factor for a successful outcome. Human error during the Registration Process for imageless computer navigation knee arthroplasty directly affects component alignment. This cadaveric study aims to define the error in the Registration of the landmarks and the resulting error in component alignment. Five fresh frozen cadaveric limbs including the hemipelvis were used for the study. Five surgeons performed the Registration Process via a medial parapatellar approach five times. In order to identify the gold standard point, the soft tissues were stripped and the Registration was repeated by the senior author. Errors are presented as mm or degrees from the gold standard Registration. The error range in the Registration of the femoral centre in the coronal plane was 6.5mm laterally to 5.0mm medially (mean: −0.1, SD: 2.7). This resulted in a mechanical axis error of 5.2 degrees valgus to 2.9 degrees varus (mean: 0.1, SD: 1.1). In the sagittal plane this error was between −1.8 degrees (extension) and 2.7 degrees (flexion). The error in the calculation of the tibial mechanical axis ranged from −1.0 (valgus) to 2.3 (varus) degrees in the coronal plane and −3.2 degrees of extension to 1.3 degrees of flexion. Finally the error in calculating the transepicondylar axis was −11.2 to 6.3 degrees of internal rotation (mean: −3.2, SD: 3.9). The error in the Registration Process of the anatomical landmarks can result in significant malalignment of the components. The error range for the mechanical axis of the femur alone can exceed the 3 degree margin that has been previously been associated with implant longevity. The technique during the Registration Process is of paramount importance for image free computer navigation. Future research should be directed towards simplifying this Process and minimizing the effect of human error.
Stua Walke - One of the best experts on this subject based on the ideXlab platform.
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the south african medicines control council comparison of its Registration Process with australia canada singapore and switzerland
Frontiers in Pharmacology, 2019Co-Authors: Andrea Keyte, Mirsaeed Salek, Shabi Anoo, Stua WalkeAbstract:Introduction: Comparisons between regulatory authorities of similar size and regulatory characteristics facilitate value-added benchmarking and provide insight into regulatory performance. Such comparisons highlight areas for improvement as authorities move toward achieving their regulatory goals and stakeholders' demands. The aims of this study were to compare the Registration Process and the regulatory review model of the South African Medicines Control Council (MCC) to that of four other similar-sized regulatory authorities and to identify areas for improvement that may inform recommendations to the South African Health Products Regulatory Authority (SAHPRA) as it looks to re-engineer and enhance the Registration Process in South Africa. Methods: A questionnaire describing the organisational structure, the Registration Process, good review and decision-making practices of the MCC was completed by the author (AK) for the purpose of this study and validated by the Registrar of the MCC. Similar questionnaires were also completed and validated by Australia's Therapeutic Goods Administration (TGA), Canada's Health Canada, Singapore's Health Science Authority (HSA) and Switzerland's Swissmedic. Results: A comparison of the MCC regulatory Process with the four comparative agencies indicated that they all have similar requirements and employ a full-review model although the timelines for the MCC were considerably longer. However, similar quality measures were implemented by all authorities as part of their good review practices (GRevP) including prioritising transparency, communication, continuous improvement initiatives and training. Conclusion: Comparisons made through this study provided insight into the areas of the MCC Registration Process that may be improved and have informed recommendations to SAHPRA including the implementation of facilitated regulatory pathways, definition of targets for key milestones in regulatory review and formal implementation and monitoring of GRevP. In order to build quality into the review Process the application of a standardised template for the clinical assessment of medicines such as the Universal Methodology for Benefit-Risk Assessment (UMBRA) could be considered as well as enhancing transparency and communication through the application of an electronic management system and the development of publicly available summaries for the basis of approval.
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the turkish medicines and medical devices agency comparison of its Registration Process with australia canada saudi arabia and singapore
Frontiers in Pharmacology, 2018Co-Authors: Emel Mashaki Ceyha, Hakki Gursoz, Ali Alka, Hace Cosku, Oguzha Koyuncu, Stua WalkeAbstract:Introduction: Regulatory agency comparisons can be of more value and facilitate improvements if conducted among countries with common challenges and similar health agency characteristics. A study was conducted to compare the Registration review model used by the Turkish Medicines and Medical Devices Agency (Turkiye Ilac ve Tibbi Cihaz Kurumu; TITCK) with those of four similar-sized regulatory agencies to identify areas of strength and those requiring further improvement within the TITCK in relation to the review Process as well as to assess the level of adherence to good review practices (GRevP) in order to facilitate the TITCK progress toward agency goals. Methods: A questionnaire was completed and validated by the TITCK to collect data related to agency organizational structure, regulatory review Process and decision-making practices. Similar questionnaires were completed and validated by Australia's Therapeutic Goods Administration (TGA), Health Canada, Singapore's Health Science Authority (HSA), and the Saudi Arabia Food and Drug Administration (SFDA). Results: The TITCK performs a full review for all new active substance (NAS) applications. Submission of a Certificate of Pharmaceutical product (CPP) with an application is not required; however, evidence of approval in another country is required for final authorization by the TITCK. Pricing data are not required by the TITCK at the time of submission; however, pricing must be completed to enable products to be commercially available. Mean approval times at the TITCK exceeded the agency's overall target time suggesting room for improved performance, consistency, and Process predictability. Measures of GRevP are in place, but the implementation by the TITCK is not currently formalized. Discussion: Comparisons made through this study enabled recommendations to the TITCK that include streamlining the good manufacturing practice (GMP) Process by sharing GMP inspection outcomes and certificates issued by other authorities, thus avoiding the delays by the current Process; removing the requirement for prior approval or CPP; introducing shared or joint reviews with other similar regulatory authorities; formally implementing and monitoring GRevP; defining target timing for each review milestone; redefining the pricing Process; and improving transparency by developing publicly available summaries for the basis of approval.
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the jordan food and drug administration comparison of its Registration Process with australia canada saudi arabia and singapore
Pharmaceutical medicine, 2017Co-Authors: Wesal Salem Al Haqaish, Stua Walke, Hayel Obeida, Prisha PatelAbstract:This study outlines the current regulatory review Process and good review practices (GRevPs) at the Jordan Food and Drug Administration (JFDA) and compares them with those of regulatory agencies in Australia, Canada, Saudi Arabia and Singapore to gauge how well the JFDA is performing. We identify opportunities for further development of the JFDA as a key global reference agency. Personnel within the JFDA completed a questionnaire comprising four sections: organisation, key milestones, review timelines, and GRevPs. The same questionnaire was used concurrently to gather information from Australia’s Therapeutic Goods Administration (TGA), Health Canada, the Saudi Food and Drug Authority (SFDA) and Singapore’s Health Sciences Authority (HSA). The JFDA conducts an abridged review for new active substances and requires a certificate of pharmaceutical product (CPP) at the time of submission and 6 months of pharmacovigilance data at the time of the final review as well as full pharmaceutical, chemistry, manufacturing and controls (CMC) and clinical data at the time of submission. A written summary and tabulated data are required for non-clinical data. The four comparator agencies conduct full assessments; the SFDA also requires a CPP, and the JFDA and SFDA both require pricing information at submission. All agencies have established target timelines, and the JFDA, SFDA, TGA and HSA currently exceed those targets. All agencies have also developed GRevPs as well as training and continuous-improvement Processes. The JFDA has achieved significant success in its role as a regulatory agency by setting and implementing clear regulations in line with international guidance. It is recognised as a training centre in the region, with considerable achievements in the development of its activities by simplifying and improving requirements, procedures and actions. It also publishes information regarding guidance, procedures, drug application submissions and Registration dates for all new chemical entities on its website. The relationship between the JFDA and the pharmaceutical sector in Jordan has resulted in balanced, practical, internationally compatible regulations and demonstrates a viable model of collaboration. To assist the JFDA in its efforts to become a key global reference agency, it is suggested that the agency explore a risk-stratification approach to the regulatory review; accept CPPs after dossier submission or use alternatives to the CPP; conduct pricing evaluations in parallel with scientific assessments; establish defined target times for review milestones and improve internal tracking systems to monitor these milestones; and make certain information transparent to all stakeholders by publishing a summary basis of approval.
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the saudi arabia food and drug authority an evaluation of the Registration Process and good review practices in saudi arabia in comparison with australia canada and singapore
Pharmaceutical medicine, 2016Co-Authors: Hajed Hasha, Prisha Patel, Ibrahim A Aljuffali, Stua WalkeAbstract:Objective This study compares the current regulatory review Process and good review practices at the Saudi Food and Drug Authority (SFDA) with those of regulatory agencies in Australia, Canada, and Singapore and identifies opportunities for developing the SFDA as a Regional Centre of Excellence.
Christos Davatzikos - One of the best experts on this subject based on the ideXlab platform.
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deformable Registration of brain tumor images via a statistical model of tumor induced deformation
Medical Image Analysis, 2006Co-Authors: Ashraf Mohamed, Evangelia I Zacharaki, Christos Davatzikos, Dinggang ShenAbstract:Abstract An approach to the deformable Registration of three-dimensional brain tumor images to a normal brain atlas is presented. The approach involves the integration of three components: a biomechanical model of tumor mass-effect, a statistical approach to estimate the model’s parameters, and a deformable image Registration method. Statistical properties of the sought deformation map from the atlas to the image of a tumor patient are first obtained through tumor mass-effect simulations on normal brain images. This map is decomposed into the sum of two components in orthogonal subspaces, one representing inter-individual differences in brain shape, and the other representing tumor-induced deformation. For a new tumor case, a partial observation of the sought deformation map is obtained via deformable image Registration and is decomposed into the aforementioned spaces in order to estimate the mass-effect model parameters. Using this estimate, a simulation of tumor mass-effect is performed on the atlas image in order to generate an image that is similar to tumor patient’s image, thereby facilitating the atlas Registration Process. Results for a real tumor case and a number of simulated tumor cases indicate significant reduction in the Registration error due to the presented approach as compared to the direct use of deformable image Registration.
Edward T Davis - One of the best experts on this subject based on the ideXlab platform.
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the effect of the Registration Process error on component alignment during imageless computer navigation for knee arthroplasty a cadaveric study
Orthopaedic Proceedings, 2018Co-Authors: Joseph Pagkalos, Edward T Davis, P Gallie, K Macgroarty, James P Waddell, Emil H SchemitschAbstract:Implant alignment in knee arthroplasty has been identified as critical factor for a successful outcome. Human error during the Registration Process for imageless computer navigation knee arthroplasty directly affects component alignment. This cadaveric study aims to define the error in the Registration of the landmarks and the resulting error in component alignment.Five fresh frozen cadaveric limbs including the hemipelvis were used for the study. Five surgeons performed the Registration Process via a medial parapatellar approach five times. In order to identify the gold standard point, the soft tissues were stripped and the Registration was repeated by the senior author. Errors are presented as mm or degrees from the gold standard Registration.The error range in the Registration of the femoral centre in the coronal plane was 6.5mm laterally to 5.0mm medially (mean: −0.1, SD: 2.7). This resulted in a mechanical axis error of 5.2 degrees valgus to 2.9 degrees varus (mean: 0.1, SD: 1.1). In the sagittal pla...
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a comparison of Registration errors with imageless computer navigation during mis total knee arthroplasty versus standard incision total knee arthroplasty a cadaveric study
Computer Aided Surgery, 2015Co-Authors: Edward T Davis, Joseph Pagkalos, P Gallie, K Macgroarty, James P Waddell, Emil H SchemitschAbstract:AbstractOptimal component alignment in total knee arthroplasty has been associated with better functional outcome as well as improved implant longevity. The ability to align components optimally during minimally invasive (MIS) total knee replacement (TKR) has been a cause of concern. Computer navigation is a useful aid in achieving the desired alignment although it is limited by the error during the manual Registration of landmarks. Our study aims to compare the Registration Process error between a standard and a MIS surgical approach. We hypothesized that performing the Registration error via an MIS approach would increase the Registration Process error. Five fresh frozen lower limbs were routinely prepared and draped. The Registration Process was performed through an MIS approach. This was then extended to the standard approach and the Registration was performed again. Two surgeons performed the Registration Process five times with each approach. Performing the Registration Process through the MIS appro...
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defining the errors in the Registration Process during imageless computer navigation in total knee arthroplasty a cadaveric study
Journal of Arthroplasty, 2014Co-Authors: Edward T Davis, Joseph Pagkalos, P Gallie, K Macgroarty, James P Waddell, Emil H SchemitschAbstract:Computer assisted arthroplasty was introduced as a means to optimally align implants in order to improve function and longevity. The error during the manual Registration of landmarks and its effect on component alignment was investigated in this study. Five fresh frozen lower limbs were used and the Registration Process was performed five times by five surgeons. The error range of the mechanical axis of the femur in the coronal plane was 5.2 degrees of valgus to 2.9 degrees of varus whilst the transepicondylar axis error was 11.1 degrees of external to 6.3 of internal rotation. Those figures suggest that the Registration error alone can have a significant effect on the alignment of the implant.
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the effect of the Registration Process error on component alignment during imageless computer navigation for knee arthroplasty a cadaveric study
Journal of Bone and Joint Surgery-british Volume, 2013Co-Authors: Joseph Pagkalos, Edward T Davis, P Gallie, K Macgroarty, James P Waddell, Emil H SchemitschAbstract:Implant alignment in knee arthroplasty has been identified as critical factor for a successful outcome. Human error during the Registration Process for imageless computer navigation knee arthroplasty directly affects component alignment. This cadaveric study aims to define the error in the Registration of the landmarks and the resulting error in component alignment. Five fresh frozen cadaveric limbs including the hemipelvis were used for the study. Five surgeons performed the Registration Process via a medial parapatellar approach five times. In order to identify the gold standard point, the soft tissues were stripped and the Registration was repeated by the senior author. Errors are presented as mm or degrees from the gold standard Registration. The error range in the Registration of the femoral centre in the coronal plane was 6.5mm laterally to 5.0mm medially (mean: −0.1, SD: 2.7). This resulted in a mechanical axis error of 5.2 degrees valgus to 2.9 degrees varus (mean: 0.1, SD: 1.1). In the sagittal plane this error was between −1.8 degrees (extension) and 2.7 degrees (flexion). The error in the calculation of the tibial mechanical axis ranged from −1.0 (valgus) to 2.3 (varus) degrees in the coronal plane and −3.2 degrees of extension to 1.3 degrees of flexion. Finally the error in calculating the transepicondylar axis was −11.2 to 6.3 degrees of internal rotation (mean: −3.2, SD: 3.9). The error in the Registration Process of the anatomical landmarks can result in significant malalignment of the components. The error range for the mechanical axis of the femur alone can exceed the 3 degree margin that has been previously been associated with implant longevity. The technique during the Registration Process is of paramount importance for image free computer navigation. Future research should be directed towards simplifying this Process and minimizing the effect of human error.
Aymeric Leray - One of the best experts on this subject based on the ideXlab platform.
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statistical performance analysis of a fast super resolution technique using noisy translations
IEEE Transactions on Image Processing, 2016Co-Authors: Pierre Chainais, Aymeric LerayAbstract:The Registration Process is a key step for super-resolution (SR) reconstruction. More and more devices permit to overcome this bottleneck using a controlled positioning system, e.g., sensor shifting using a piezoelectric stage. This makes possible to acquire multiple images of the same scene at different controlled positions. Then, a fast SR algorithm can be used for efficient SR reconstruction. In this case, the optimal use of $r^{2}$ images for a resolution enhancement factor $r$ is generally not enough to obtain satisfying results due to the random inaccuracy of the positioning system. Thus, we propose to take several images around each reference position. We study the error produced by the SR algorithm due to spatial uncertainty as a function of the number of images per position. We obtain a lower bound on the number of images that is necessary to ensure a given error upper bound with probability higher than some desired confidence level. Such results give precious hints to the design of SR systems.
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statistical performance analysis of a fast super resolution technique using noisy translations
arXiv: Methodology, 2014Co-Authors: Pierre Chainais, Aymeric LerayAbstract:It is well known that the Registration Process is a key step for super-resolution reconstruction. In this work, we propose to use a piezoelectric system that is easily adaptable on all microscopes and telescopes for controlling accurately their motion (down to nanometers) and therefore acquiring multiple images of the same scene at different controlled positions. Then a fast super-resolution algorithm \cite{eh01} can be used for efficient super-resolution reconstruction. In this case, the optimal use of $r^2$ images for a resolution enhancement factor $r$ is generally not enough to obtain satisfying results due to the random inaccuracy of the positioning system. Thus we propose to take several images around each reference position. We study the error produced by the super-resolution algorithm due to spatial uncertainty as a function of the number of images per position. We obtain a lower bound on the number of images that is necessary to ensure a given error upper bound with probability higher than some desired confidence level.
