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8. Rapid near-optimal aerospace plane trajectory generation and guidance

Author

Corban, J. E, Calise, A. J, and Flandro, G. A

Subjects
Spacecraft Design, Testing And Performance
Abstract

Problems associated with onboard trajectory optimization, propulsion system cycle selection, and the synthesis of guidance laws are addressed for ascent to low earth orbit of an airbreathing, single-stage-to-orbit vehicle. A multicycle propulsion system is assumed that incorporates turbojet, ramjet, scramjet, and rocket engines. An energy state approximation is applied to a singularly perturbed, four-state dynamic model for flight of a point mass over a spherical nonrotating earth. An algorithm is then derived for generating both the fuel-optimal climb profile and the guidance commands required to follow that profile. In particular, analytic switching conditions are derived that, under appropriate assumptions, efficiently govern optimal transition from one propulsion cycle to another. The algorithm proves to be computationally efficient and suitable for real-time implementation. The paper concludes with the presentation of representative numerical results that illustrate the nature of the fuel-optimal climb paths and the tracking performance of the guidance algorithm.

Published
1991

9. Rapid near-optimal aerospace plane trajectory generation and guidance

Author

Calise, A. J, Corban, J. E, and Markopoulos, N

Subjects
Aircraft Stability And Control
Abstract

Effort was directed toward the problems of the real time trajectory optimization and guidance law development for the National Aerospace Plane (NASP) applications. In particular, singular perturbation methods were used to develop guidance algorithms suitable for onboard, real time implementation. The progress made in this research effort is reported.

Published
1991

10. Nondimensional forms for singular perturbation analyses of aircraft energy climbs

Author

Calise, A. J, Markopoulos, N, and Corban, J. E

Subjects
Aircraft Design, Testing And Performance
Abstract

This paper proposes a systematic approach for identifying the perturbation parameter in singular perturbation analysis of aircraft optimal guidance, and in particular considers a family of problems related to aircraft energy climbs. The approach, which is based on a nondimensionalization of the equations of motion, is used to evaluatae the appropriateness of forced singular perturbation formulations used in the past for transport and fighter aircraft, and to assess the applicability of energy state approximations and singular perturbation analysis for airbreathing transatmospheric vehicles with hypersonic cruise and orbital capabilities.

Published
1991

11. Optimal control of singularly perturbed nonlinear systems with state-variable inequality constraints

Author

Calise, A. J and Corban, J. E

Subjects
Cybernetics
Abstract

The established necessary conditions for optimality in nonlinear control problems that involve state-variable inequality constraints are applied to a class of singularly perturbed systems. The distinguishing feature of this class of two-time-scale systems is a transformation of the state-variable inequality constraint, present in the full order problem, to a constraint involving states and controls in the reduced problem. It is shown that, when a state constraint is active in the reduced problem, the boundary layer problem can be of finite time in the stretched time variable. Thus, the usual requirement for asymptotic stability of the boundary layer system is not applicable, and cannot be used to construct approximate boundary layer solutions. Several alternative solution methods are explored and illustrated with simple examples.

Published
1990

12. Rapid near-optimal trajectory generation and guidance law development for single-stage-to-orbit airbreathing vehicles

Author

Calise, A. J, Flandro, G. A, and Corban, J. E

Subjects
Spacecraft Design, Testing And Performance
Abstract

General problems associated with on-board trajectory optimization, propulsion system cycle selection, and with the synthesis of guidance laws were addressed for an ascent to low-earth-orbit of an air-breathing single-stage-to-orbit vehicle. The NASA Generic Hypersonic Aerodynamic Model Example and the Langley Accelerator aerodynamic sets were acquired and implemented. Work related to the development of purely analytic aerodynamic models was also performed at a low level. A generic model of a multi-mode propulsion system was developed that includes turbojet, ramjet, scramjet, and rocket engine cycles. Provisions were made in the dynamic model for a component of thrust normal to the flight path. Computational results, which characterize the nonlinear sensitivity of scramjet performance to changes in vehicle angle of attack, were obtained and incorporated into the engine model. Additional trajectory constraints were introduced: maximum dynamic pressure; maximum aerodynamic heating rate per unit area; angle of attack and lift limits; and limits on acceleration both along and normal to the flight path. The remainder of the effort focused on required modifications to a previously derived algorithm when the model complexity cited above was added. In particular, analytic switching conditions were derived which, under appropriate assumptions, govern optimal transition from one propulsion mode to another for two cases: the case in which engine cycle operations can overlap, and the case in which engine cycle operations are mutually exclusive. The resulting guidance algorithm was implemented in software and exercised extensively. It was found that the approximations associated with the assumed time scale separation employed in this work are reasonable except over the Mach range from roughly 5 to 8. This phenomenon is due to the very large thrust capability of scramjets in this Mach regime when sized to meet the requirement for ascent to orbit. By accounting for flight path angle and flight path angle rate in construction of the flight path over this Mach range, the resulting algorithm provides the means for rapid near-optimal trajectory generation and propulsion cycle selection over the entire Mach range from take-off to orbit.

Published
1990

14. Comparing very low birth weight versus very low gestation cohort methods for outcome analysis of high risk preterm infants.

Author

Austin N., Andersen C., Darlow B., Broadbent R., Corban J., Mildenhall L., Battin M., Bourchier D., Richardson V., Haslam R., Rajadurai V.S., Kajetanowicz A., Synnes A., Rouvinez-Bouali N., Piedboeuf B., Bertelle V., Bulleid B., Yee W., Shivananda S., Lee K.-S., Seshia M., Barrington K., Lefebvre F., McMillan D., Andrews W., Kovacs L., Dow K., da Silva O., Riley P., Peliowski A., Aziz K., Cieslak Z., Kalapesi Z., Sankaran K., Faucher D., Alvaro R., Canning R., Ojah C., Monterrosa L., Dunn M., Sorokan T., Harrison A., Nwaesei C., Adie M., Hakansson S., Segerdahl N., Morad T., Moren S., Stenberg A., Simonsson C., Stigsson L., Christensen J.L., Amasn L., Ingemanson F., osterdal L., Ellstrom K.-G., Abrahamsson T., Heimdahl I., Hagg T., Hedlund A., Lund E.E., Westrup B., Sarman I., Jobe A.S., Fredsriksson M., Palm A., Malmstrom B., Lindberg E., Ljungdahl O., Eriksson K., Koller-Smith L.I.M., Shah P., Ye X.Y., Sjors G., Wang Y.A., Chow S.S.W., Darlow B.A., Lee S.K., Hakanson S., Lui K., Marshall P., Craven P., Simmer K., Stack J., Knight D., Watkins A., Ramsden A., Tan K., Bawden K., Downe L., Singde V., Stewart M., Berry A., Hunt R., Kilburn C., Dargaville P., Paradisis M., Evans N., Reid S., Cartwright D., Kuschel C., Doyle L., Numa A., Kecskes Z., Badawi N., Koh G., Resnick S., Tracy M., Tarnow-Mordi W., Austin N., Andersen C., Darlow B., Broadbent R., Corban J., Mildenhall L., Battin M., Bourchier D., Richardson V., Haslam R., Rajadurai V.S., Kajetanowicz A., Synnes A., Rouvinez-Bouali N., Piedboeuf B., Bertelle V., Bulleid B., Yee W., Shivananda S., Lee K.-S., Seshia M., Barrington K., Lefebvre F., McMillan D., Andrews W., Kovacs L., Dow K., da Silva O., Riley P., Peliowski A., Aziz K., Cieslak Z., Kalapesi Z., Sankaran K., Faucher D., Alvaro R., Canning R., Ojah C., Monterrosa L., Dunn M., Sorokan T., Harrison A., Nwaesei C., Adie M., Hakansson S., Segerdahl N., Morad T., Moren S., Stenberg A., Simonsson C., Stigsson L., Christensen J.L., Amasn L., Ingemanson F., osterdal L., Ellstrom K.-G., Abrahamsson T., Heimdahl I., Hagg T., Hedlund A., Lund E.E., Westrup B., Sarman I., Jobe A.S., Fredsriksson M., Palm A., Malmstrom B., Lindberg E., Ljungdahl O., Eriksson K., Koller-Smith L.I.M., Shah P., Ye X.Y., Sjors G., Wang Y.A., Chow S.S.W., Darlow B.A., Lee S.K., Hakanson S., Lui K., Marshall P., Craven P., Simmer K., Stack J., Knight D., Watkins A., Ramsden A., Tan K., Bawden K., Downe L., Singde V., Stewart M., Berry A., Hunt R., Kilburn C., Dargaville P., Paradisis M., Evans N., Reid S., Cartwright D., Kuschel C., Doyle L., Numa A., Kecskes Z., Badawi N., Koh G., Resnick S., Tracy M., and Tarnow-Mordi W.

Abstract

Background: Compared to very low gestational age (<32 weeks, VLGA) cohorts, very low birth weight (<1500 g; VLBW) cohorts are more prone to selection bias toward small-for-gestational age (SGA) infants, which may impact upon the validity of data for benchmarking purposes. Method(s): Data from all VLGA or VLBW infants admitted in the 3 Networks between 2008 and 2011 were used. Two-thirds of each network cohort was randomly selected to develop prediction models for mortality and composite adverse outcome (CAO: mortality or cerebral injuries, chronic lung disease, severe retinopathy or necrotizing enterocolitis) and the remaining for internal validation. Areas under the ROC curves (AUC) of the models were compared. Result(s): VLBW cohort (24,335 infants) had twice more SGA infants (20.4% vs. 9.3%) than the VLGA cohort (29,180 infants) and had a higher rate of CAO (36.5% vs. 32.6%). The two models had equal prediction power for mortality and CAO (AUC 0.83), and similarly for all other cross-cohort validations (AUC 0.81-0.85). Neither model performed well for the extremes of birth weight for gestation (<1500 g and >=32 weeks, AUC 0.50-0.65; >=1500 g and <32 weeks, AUC 0.60-0.62). Conclusion(s): There was no difference in prediction power for adverse outcome between cohorting VLGA or VLBW despite substantial bias in SGA population. Either cohorting practises are suitable for international benchmarking.Copyright © 2017 The Author(s).

Published
2017

15. Comparing very low birth weight versus very low gestation cohort methods for outcome analysis of high risk preterm infants

Author

Koller-Smith, LIM, Shah, PS, Ye, XY, Sjörs, G, Wang, YA, Chow, SSW, Darlow, BA, Lee, SK, Håkanson, S, Lui, K, Marshall, P, Craven, P, Simmer, K, Stack, J, Knight, D, Watkins, A, Ramsden, A, Tan, K, Bawden, K, Downe, L, Singde, V, Stewart, M, Berry, A, Hunt, R, Kilburn, C, Dargaville, P, Paradisis, M, Evans, N, Reid, S, Cartwright, D, Kuschel, C, Doyle, L, Numa, A, Kecskes, Z, Badawi, N, Koh, G, Resnick, S, Tracy, M, Tarnow-Mordi, W, Andersen, C, Austin, N, Darlow, B, Broadbent, R, Corban, J, Mildenhall, L, Battin, M, Bourchier, D, Richardson, V, Haslam, R, Rajadurai, VS, Kajetanowicz, A, Synnes, A, Rouvinez-Bouali, N, Piedboeuf, B, Bertelle, V, Bulleid, B, Yee, W, Shivananda, S, Lee, KS, Seshia, M, Barrington, K, Lefebvre, F, McMillan, D, Andrews, W, Kovacs, L, Dow, K, da Silva, O, Riley, P, Peliowski, A, Aziz, K, Cieslak, Z, Kalapesi, Z, Sankaran, K, Faucher, D, Alvaro, R, Canning, R, Ojah, C, Monterrosa, L, Dunn, M, Sorokan, T, Harrison, A, Nwaesei, C, Adie, M, Håkansson, S, Segerdahl, N, Morad, T, Morén, S, Stenberg, Å, Simonsson, C, Stigsson, L, Christensen, JL, Åmasn, L, Ingemanson, F, österdal, L, Ellström, KG, Abrahamsson, T, Heimdahl, I, Hägg, T, Hedlund, A, Lund, EE, Koller-Smith, LIM, Shah, PS, Ye, XY, Sjörs, G, Wang, YA, Chow, SSW, Darlow, BA, Lee, SK, Håkanson, S, Lui, K, Marshall, P, Craven, P, Simmer, K, Stack, J, Knight, D, Watkins, A, Ramsden, A, Tan, K, Bawden, K, Downe, L, Singde, V, Stewart, M, Berry, A, Hunt, R, Kilburn, C, Dargaville, P, Paradisis, M, Evans, N, Reid, S, Cartwright, D, Kuschel, C, Doyle, L, Numa, A, Kecskes, Z, Badawi, N, Koh, G, Resnick, S, Tracy, M, Tarnow-Mordi, W, Andersen, C, Austin, N, Darlow, B, Broadbent, R, Corban, J, Mildenhall, L, Battin, M, Bourchier, D, Richardson, V, Haslam, R, Rajadurai, VS, Kajetanowicz, A, Synnes, A, Rouvinez-Bouali, N, Piedboeuf, B, Bertelle, V, Bulleid, B, Yee, W, Shivananda, S, Lee, KS, Seshia, M, Barrington, K, Lefebvre, F, McMillan, D, Andrews, W, Kovacs, L, Dow, K, da Silva, O, Riley, P, Peliowski, A, Aziz, K, Cieslak, Z, Kalapesi, Z, Sankaran, K, Faucher, D, Alvaro, R, Canning, R, Ojah, C, Monterrosa, L, Dunn, M, Sorokan, T, Harrison, A, Nwaesei, C, Adie, M, Håkansson, S, Segerdahl, N, Morad, T, Morén, S, Stenberg, Å, Simonsson, C, Stigsson, L, Christensen, JL, Åmasn, L, Ingemanson, F, österdal, L, Ellström, KG, Abrahamsson, T, Heimdahl, I, Hägg, T, Hedlund, A, and Lund, EE

Abstract

© 2017 The Author(s). Background: Compared to very low gestational age (<32 weeks, VLGA) cohorts, very low birth weight (<1500 g; VLBW) cohorts are more prone to selection bias toward small-for-gestational age (SGA) infants, which may impact upon the validity of data for benchmarking purposes. Method: Data from all VLGA or VLBW infants admitted in the 3 Networks between 2008 and 2011 were used. Two-thirds of each network cohort was randomly selected to develop prediction models for mortality and composite adverse outcome (CAO: mortality or cerebral injuries, chronic lung disease, severe retinopathy or necrotizing enterocolitis) and the remaining for internal validation. Areas under the ROC curves (AUC) of the models were compared. Results: VLBW cohort (24,335 infants) had twice more SGA infants (20.4% vs. 9.3%) than the VLGA cohort (29,180 infants) and had a higher rate of CAO (36.5% vs. 32.6%). The two models had equal prediction power for mortality and CAO (AUC 0.83), and similarly for all other cross-cohort validations (AUC 0.81-0.85). Neither model performed well for the extremes of birth weight for gestation (<1500 g and ≥32 weeks, AUC 0.50-0.65; ≥1500 g and <32 weeks, AUC 0.60-0.62). Conclusion: There was no difference in prediction power for adverse outcome between cohorting VLGA or VLBW despite substantial bias in SGA population. Either cohorting practises are suitable for international benchmarking.

Published
2017

16. Standardised neonatal parenteral nutrition formulations - an Australasian group consensus 2012.

Author

Morris S., Sinn J., Lui K., Kent A., Trivedi A., Yaacoub D., Marshall P., Birch P., Corban J., Natthondan V., Kwee Ching S., Wake C., Vaidya U., Tobiansky R., Pazanin N., Downe L., Deshpande G., De Paoli T., Colvin J., Ravindranathan H., Gupta N., Gibney D., Luig M., Ng K., Pham T., McPhee A., Tan K., Bolisetty S., Osborn D., Morris S., Sinn J., Lui K., Kent A., Trivedi A., Yaacoub D., Marshall P., Birch P., Corban J., Natthondan V., Kwee Ching S., Wake C., Vaidya U., Tobiansky R., Pazanin N., Downe L., Deshpande G., De Paoli T., Colvin J., Ravindranathan H., Gupta N., Gibney D., Luig M., Ng K., Pham T., McPhee A., Tan K., Bolisetty S., and Osborn D.

Abstract

Standardised parenteral nutrition formulations are routinely used in the neonatal intensive care units in Australia and New Zealand. In 2010, a multidisciplinary group was formed to achieve a consensus on the formulations acceptable to majority of the neonatal intensive care units. Literature review was undertaken for each nutrient and recommendations were developed in a series of meetings held between November 2010 and April 2011. Three standard and 2 optional amino acid/dextrose formulations and one lipid emulsion were agreed by majority participants in the consensus. This has a potential to standardise neonatal parenteral nutrition guidelines, reduce costs and prescription errors. © 2014 Bolisetty et al.; licensee BioMed Central Ltd.

Published
2014

17. On-Line Trajectory Optimization for Autonomous Air Vehicles

Author

GUIDED SYSTEMS TECHNOLOGIES MCDONOUGH GA, Corban, J. E., Twigg, Shannon, Ries, Tobias, Yang, Bong-Jun, Johnson, Eric, Calise, Anthony, GUIDED SYSTEMS TECHNOLOGIES MCDONOUGH GA, Corban, J. E., Twigg, Shannon, Ries, Tobias, Yang, Bong-Jun, Johnson, Eric, and Calise, Anthony

Abstract

Successful operation of next-generation unmanned air vehicles will demand a high level of autonomy. Autonomous low-level operation in a complex environment dictates a need for onboard, robust, reliable and efficient trajectory optimization. In this report, we develop and demonstrate an innovative combination of traditional analytical and numerical solution procedures to produce efficient, robust and reliable means for nonlinear flight path optimization in the presence of time-varying obstacles and threats. The trajectory generation problem is first formulated as an optimization problem using reduced-order dynamics that result from the natural time-scale separation that exists in the aircraft dynamics. Terrain information is incorporated directly into the formulation of the reduced-order dynamics, which significantly reduces the computational load and leads to a path planning solution that can be implemented in real-time. Various cases of terrain, pop-up obstacles/threats, and targets are simulated. A representative optimal trajectory is generated with in a high fidelity full-order nonlinear aircraft dynamics and compared with a solution obtained from a reduced-order optimization. The developed algorithm is flight demonstrated with a fixed-wing unmanned aircraft test-bed in which a neural network-based adaptive autopilot is integrated with the on-line trajectory optimization algorithm., Prepared in cooperation with with the Georgia Institute of Technology and the University of Stuttgart. The original document contains color images.

Published
2007

18. Biological Inspired Direct Adaptive Guidance and Control for Autonomous Flight Systems

Author

GUIDED SYSTEMS TECHNOLOGIES MCDONOUGH GA, Corban, J. E., Gilbert, Cole, Calise, Anthony J., Tannenbaum, Allen R., GUIDED SYSTEMS TECHNOLOGIES MCDONOUGH GA, Corban, J. E., Gilbert, Cole, Calise, Anthony J., and Tannenbaum, Allen R.

Abstract

The work at Cornell centered on developing experimental methods to characterize flesh fly pursuit evasions, and resulted in the maturation of effective means to capture the 3-D trajectory, as well as body and head orientation. The data was processed at first by hand, and later using image processing algorithms to develop 3-D visualizations at the track, including the head orientation, and ultimately to map the location of the target on the eye during the pursuit. The results provided a means to compare the guidance strategy of the fly with traditional proportional navigation, and to look for inspiration in the development of new guidance laws. Work was also completed to introduce clutter into the encounter. While a much greater understanding of the tracking and guidance strategy of the flesh fly was developed and documented, the work has not yet resulted in the discovery of a better alternative to traditional engineered guidance laws.

Published
2004

19. On-Line Trajectory Optimization for Autonomous Air Vehicles

Author

GUIDED SYSTEMS TECHNOLOGIES MCDONOUGH GA, Corban, J. Eric, Johnson, Eric N., Calise, Anthony J., Twigg, Shannon, GUIDED SYSTEMS TECHNOLOGIES MCDONOUGH GA, Corban, J. Eric, Johnson, Eric N., Calise, Anthony J., and Twigg, Shannon

Abstract

Successful operation of next-generation unmanned air vehicles will demand a high level of autonomy. Autonomous low-level operation in a high-threat environment dictates a need for on-hoard, robust, reliable and efficient trajectory optimization. in this report, we develop and demonstrate an innovative combination of traditional analytical and numerical solution procedures to produce efficient, robust and reliable means for nonlinear Light path optimization in the presence of time-varying obstacles and threats. The solution procedure exploits the natural time-scale separation that exists in the aircraft dynamics using singular perturbation theory. A reduced order problem involving only the kinematics of the position subspace is treated numerically. The nonlinear aircraft dynamics are to be treated analytically in phase II using a boundary layer analysis that results in an optimal feedback guidance solution. The developed algorithms were coupled with a neural network adaptive autopilot and integrated in an existing unmanned test-bed. This report documents the phase I effort, which produced a demonstration of the developed algorithm in near-real-time flight simulation, and included a simple evaluation of tracking computed trajectories on a rotary wing UAV.

Published
2003

22. Optimal guidance and propulsion control for transatmospheric vehicles

Author

Corban, J. E, Calise, A. J, and Flandro, G. A

Subjects
Launch Vehicles And Space Vehicles
Abstract

Problems associated with on-board trajectory optimization and with the synthesis of guidance laws are addressed for ascent to LEO of an air-breathing, single-stage-to-orbit vehicle. A multimode propulsion system is assumed which incorporates turbojet, ramjet, scramjet, and rocket engines. An energy-state approximation is applied to a four-state dynamic model for flight of a point mass over a spherical nonrotating earth. An algorithm for generating fuel-optimal climb profiles is derived via singular perturbation theory. This algorithm results from application of the minimum principle to a low-order dynamic model that includes general functional dependence on angle of attack and a normal component of thrust. Switching conditions are derived which, under appropriate assumptions, govern optimal transition from one propulsion mode to another. The use of bank angle to modulate the magnitude of the vertical component of lift is shown to improve the index performance. Numerical results illustrate the nature of the resulting fuel-optimal climb paths.

Published
1989

23. A real-time guidance algorithm for aerospace plane optimal ascent to low earth orbit

Author

Calise, A. J, Flandro, G. A, and Corban, J. E

Subjects
Launch Vehicles And Space Vehicles
Abstract

Problems of onboard trajectory optimization and synthesis of suitable guidance laws for ascent to low Earth orbit of an air-breathing, single-stage-to-orbit vehicle are addressed. A multimode propulsion system is assumed which incorporates turbojet, ramjet, Scramjet, and rocket engines. An algorithm for generating fuel-optimal climb profiles is presented. This algorithm results from the application of the minimum principle to a low-order dynamic model that includes angle-of-attack effects and the normal component of thrust. Maximum dynamic pressure and maximum aerodynamic heating rate constraints are considered. Switching conditions are derived which, under appropriate assumptions, govern optimal transition from one propulsion mode to another. A nonlinear transformation technique is employed to derived a feedback controller for tracking the computed trajectory. Numerical results illustrate the nature of the resulting fuel-optimal climb paths.

Published
1989

24. Trajectory optimization and guidance law development for national aerospace plane applications

Author

Calise, A. J, Flandro, G. A, and Corban, J. E

Subjects
Aeronautics (General)
Abstract

The work completed to date is comprised of the following: a simple vehicle model representative of the aerospace plane concept in the hypersonic flight regime, fuel-optimal climb profiles for the unconstrained and dynamic pressure constrained cases generated using a reduced order dynamic model, an analytic switching condition for transition to rocket powered flight as orbital velocity is approached, simple feedback guidance laws for both the unconstrained and dynamic pressure constrained cases derived via singular perturbation theory and a nonlinear transformation technique, and numerical simulation results for ascent to orbit in the dynamic pressure constrained case.

Published
1988

30. A Novel Cost-Benefit Analysis for Evaluation of Complex Military Systems

Author

MILITARY ACADEMY WEST POINT NY, Byrns, Jr., Edward V., Corban, J. E., Ingalls, Stephen A., MILITARY ACADEMY WEST POINT NY, Byrns, Jr., Edward V., Corban, J. E., and Ingalls, Stephen A.

Abstract

This article presents a systematic merit function approach for the comprehensive evaluation of competing military systems. The merit function is defined to be the ratio of quantified system benefit to system life cycle cost. System benefit is measured by a unique utility function that quantifies the degree to which a given system configuration satisfies an identified set of customer requirements. This measure is derived from the information contained in Quality Function Deployment tables. The second portion of the merit function is a life cycle cost measure that can be developed using any valid estimation technique. With this merit function approach, the cost effectiveness of complex systems can be quantified. Comparison of the quantified merit of competing systems then provides for objective and reliable decision making. The merit function approach is demonstrated by an evaluation of two attack helicopter configurations., Published in Acquisition Review Quarterly, p1-20, Winter 1995. Prepared in collaboration with Systems Planning and Analysis, Inc., Falls Church, VA and Guided Systems Technologies, Atlanta, GA.

Published
1995

38. Comparing very low birth weight versus very low gestation cohort methods for outcome analysis of high risk preterm infants

Author

Louise Koller-Smith, Shah, Ps, Ye, Xy, Sjörs, G., Wang, Ya, Chow, Ssw, Darlow, Ba, Lee, Sk, Håkanson, S., Lui, K., Marshall, P., Craven, P., Simmer, K., Stack, J., Knight, D., Watkins, A., Ramsden, A., Tan, K., Bawden, K., Downe, L., Singde, V., Stewart, M., Berry, A., Hunt, R., Kilburn, C., Dargaville, P., Paradisis, M., Evans, N., Reid, S., Cartwright, D., Kuschel, C., Doyle, L., Numa, A., Kecskes, Z., Badawi, N., Koh, G., Resnick, S., Tracy, M., Tarnow-Mordi, W., Andersen, C., Austin, N., Darlow, B., Broadbent, R., Corban, J., Mildenhall, L., Battin, M., Bourchier, D., Richardson, V., Haslam, R., Rajadurai, Vs, Kajetanowicz, A., Synnes, A., Rouvinez-Bouali, N., Piedboeuf, B., Bertelle, V., Bulleid, B., Yee, W., Shivananda, S., Lee, Ks, Seshia, M., Barrington, K., Lefebvre, F., Mcmillan, D., Andrews, W., Kovacs, L., Dow, K., Da Silva, O., Riley, P., Peliowski, A., Aziz, K., Cieslak, Z., Kalapesi, Z., Sankaran, K., Faucher, D., Alvaro, R., Canning, R., Ojah, C., Monterrosa, L., Dunn, M., Sorokan, T., Harrison, A., Nwaesei, C., Adie, M., Håkansson, S., Segerdahl, N., Morad, T., Morén, S., Stenberg, Å, Simonsson, C., Stigsson, L., Christensen, Jl, Åmasn, L., Ingemanson, F., Österdal, L., Ellström, Kg, Abrahamsson, T., Heimdahl, I., Hägg, T., Hedlund, A., and Lund, Ee

Subjects
Male, Canada, Gestational Age, Infant, Premature, Diseases, Pediatrics, Decision Support Techniques, Risk Factors, Infant Mortality, Humans, Infant, Very Low Birth Weight, Hospital Mortality, Selection Bias, Retrospective Studies, Sweden, Models, Statistical, Infant, Newborn, Australia, Infant, Prognosis, Benchmarking, ROC Curve, Area Under Curve, Infant, Extremely Premature, Infant, Small for Gestational Age, Intensive Care, Neonatal, Female, Infant, Premature, New Zealand
Abstract

© 2017 The Author(s). Background: Compared to very low gestational age (

40. Camphor toxicity.

Author

Emery, DP, Corban, JG, Emery, D P, and Corban, J G

Subjects
CAMPHOR, POISONING, ACTIVATED carbon, VENTILATION, TOXICOLOGY, THERAPEUTICS, ANTICONVULSANTS, DIAZEPAM, EDUCATION of parents, CHARCOAL, ANTIDOTES, STATUS epilepticus treatment, PHENOBARBITAL, ARTIFICIAL respiration, PRODUCT safety, STATUS epilepticus
Abstract

Camphor ingestion led to status epilepticus in a 20-month-old girl who required intubation and ventilation. She was treated with intravenous valium and phenobarbitone, and nasogastric activated charcoal. She made a complete neurological recovery. A number of products containing a high concentration of camphor were found to be available in the local community. [ABSTRACT FROM AUTHOR]

Published
1999
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42. Modular baseplate augmentation: a simple and effective method for addressing eccentric glenoid wear.

Author

Corban J, Bowler AR, Glass EA, Brownhill JR, Myers C, Hodorek B, Purdy M, Vasconcellos D, Le K, Austin LS, Cuff DJ, Murthi AM, Smith MJ, Wiater JM, and Jawa A

Abstract

Background: Augmented baseplates can be effective at addressing eccentric glenoid wear in reverse total shoulder arthroplasty. However, these implants often come in a limited number of predetermined shapes that require additional reaming to ensure adequate glenoid seating. This typically involves complex instrumentation and can have a negative impact on implant stability. Modular baseplate augmentation based on intraoperative measurements may allow for more precise defect filling while preserving glenoid bone. The purpose of this investigation was to assess the stability of a novel ringed baseplate with modular augmentation in comparison with nonaugmented standard and ringed baseplate designs., Methods: In this biomechanical study, baseplate micromotion was tested for 3 constructs according to the American Society for Testing and Materials guidelines. The constructs included a nonaugmented curved baseplate, a nonaugmented ringed baseplate, and a ringed baseplate with an 8-mm locking modular augmentation peg. The nonaugmented constructs were mounted flush onto polyurethane foam blocks, whereas the augmented baseplate was mounted on a polyurethane block with a simulated defect. Baseplate displacement was measured before and after 100,000 cycles of cyclic loading., Results: Before cyclic loading, the nonaugmented and augmented ringed baseplates both demonstrated significantly less micromotion than the nonaugmented curved baseplate design (81.1 μm vs. 97.2 μm vs. 152.7 μm; P = .009). After cyclic loading, both ringed constructs continued to have significantly less micromotion than the curved design (105.5 μm vs. 103.2 μm vs. 136.6 μm; P < .001). The micromotion for both ringed constructs remained below the minimum threshold required for bony ingrowth (150 μm) at all time points., Conclusions: In the setting of a simulated glenoid defect, locked modular augmentation of a ringed baseplate does not result in increased baseplate micromotion when compared with full contact nonaugmented baseplates. This design offers a simple method for tailored baseplate augmentation that can match specific variations in glenoid anatomy, limiting the need for excessive reaming and ultimately optimizing the environment for long-term implant stability., (Copyright © 2024 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Published
2024
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43. Current Evidence Based Recommendations on Rehabilitation following Arthroscopic Shoulder Surgery: Rotator Cuff, Instability, Superior Labral Pathology, and Adhesive Capsulitis.

Author

Corban J, Shah S, and Ramappa AJ

Abstract

Purpose of Review: Arthroscopy has become increasingly popular for a addressing a wide variety of shoulder pathology. However, despite increasing interest, there is still much uncertainty and variability amongst providers regarding optimal post-operative rehabilitation. This review provides an overview of the evidence underlying common rehab protocols used following arthroscopic interventions for rotator cuff disease, shoulder instability, superior labral anterior to posterior (SLAP) tears and adhesive capsulitis., Recent Findings: For small and medium sized rotator cuff tears, early motion protocols do not seem to affect healing or retear rates, however there is no difference with regards to long term functional outcomes when compared to standard motion protocols. For larger tears (> 3 cm), early active motion may be associated with impaired tendon integrity. Early range of motion following arthroscopic Bankart repair has not been shown to increase rate of recurrence, however the data on return to sport requires more granularity to effectively guide care. Further research needs to be done to compare rehab protocols following SLAP repair and arthroscopic capsular release. Rehabilitation protocols following rotator cuff surgery and anterior shoulder stabilization have garnered the most research interest. However, there is still a need for larger higher-level studies examining the long-term effects of different rehab protocols. Regarding the arthroscopic management of other types of shoulder instability, SLAP tears and adhesive capsulitis, there is paucity of high-quality evidence. This knowledge gap likely underpins the variability in different rehab protocols seen in clinical practice, highlighting the need for more research., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Published
2024
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44. Improved Clinical Outcomes After Partial Repair and In Situ Biceps Tenodesis for the Treatment of Massive Irreparable Rotator Cuff Tears.

Author

Efremov K, Veale NJ, Glass EA, Corban J, Le K, Ghobrial I, and Curtis AS

Abstract

Purpose: To present the short-term outcomes of arthroscopic in situ biceps tenodesis combined with partial rotator cuff repair in patients with massive irreparable rotator cuff tears (MIRCTs) and minimal arthritis., Methods: A retrospective review was conducted using prospectively maintained institutional databases to identify patients who had undergone a partial rotator cuff repair with in situ biceps tenodesis between March 2017 and December 2022. Patients were included if they (1) were diagnosed pre- or intraoperatively with MIRCT and (2) had complete preoperative and minimum 1-year postoperative patient-reported outcome measures., Results: Thirty-nine patients met the eligibility criteria and were included for analysis. The mean age of the study participants was 65 ± 7 years (range, 46-76) with 76.9% (n = 30) being male. The average follow-up was 21 ± 12 months (range, 12-58). Patients experienced significant improvement in visual analog scale for pain (VAS), American Shoulder and Elbow Surgeons (ASES) score, and subjective assessment numeric evaluation (SANE) score (P < .001 for all comparisons). The pre- to postoperative improvement was 3.1 ± 2.3 for VAS, 27.5 ± 20.6 for ASES, and 31.3 ± 24.8 for SANE. Postoperatively, the average scores for VAS, ASES, and SANE were 1.3 ± 1.5, 79.5 ± 17.0, and 69.6 ± 20.1, respectively. Twenty-six patients (66.7%) achieved the minimal clinically important difference (MCID) for VAS, 33 patients (84.6%) achieved the MCID for ASES, and 30 patients (76.9%) achieved the MCID for SANE., Conclusions: Partial rotator cuff repair with in situ biceps tenodesis is an effective treatment for MIRCT, leading to significant improvements in patient-reported outcome and range-of-motion measures compared to preoperative conditions., Level of Evidence: Level IV, retrospective case series., Competing Interests: Disclosures The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: A.C. is a consultant or advisor and receives nonfinancial support from Arthrex, is a board member of the Arthroscopy Association of North America, and has equity or stocks in Zimmer and Parcus. All other authors (K.E., N.J.V., E.A.G., J.C., K.L., I.G.) declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Published
2024
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45. Subscapularis Management With Biologic Augmentation in Anatomic Total Shoulder Arthroplasty.

Author

Coden G, Corban J, Minos L, Schoeller L, Georgakas P, Johnson C, Zuchelli D, Shah S, and Ross G

Abstract

Subscapularis insufficiency continues to be a source of morbidity after anatomic total shoulder arthroplasty (TSA). Biologic augmentation following rotator cuff repair has shown promising results. Here we show the technique for performing subscapularis repair after anatomic TSA using a "peel-tenotomy" and bone marrow aspirate concentrate (BMAC). A standard deltopectoral approach is performed. The peel-tenotomy is performed by leaving 0 to 10 mm of subscapularis attached to the lesser tuberosity and peeling off the remainder of the tendon. A trocar is used to aspirate bone marrow from the humeral head, which is then processed. Prior to placing the humeral stem, drill holes are placed at the bicipital groove and lesser tuberosity. Sutures are placed through each drill hole. After impacting the humeral stem, suture is passed through the subscapularis to perform a secure double row repair. Prior to tying the sutures, BMAC is applied along the margins of the subscapularis repair. After securing the sutures, additional BMAC can be applied to the subscapularis repair. It is hypothesized that this technique could provide a more robust subscapularis repair and decrease the rate of subscapularis insufficiency after TSA without any known risk or morbidity to the patient, although further research is needed to show this., Competing Interests: The authors report the following potential conflicts of interest or sources of funding: G.C. is a board member of the Journal of Orthopaedic Experience & Innovation. L.M. receives speaking and lecture fees from Heron Therapeutics. S.S. is a board member of the 10.13039/100009885American Academy of Orthopaedic Surgeons, the American Orthopaedic Society for Sports Medicine, Arthroscopy, and the Arthroscopy Association of North America; is on the editorial or governing board for Arthroscopy; and receives consulting or advisory fees from Exactech. G.R. receives consulting or advisory and speaking and lecture fees from 10.13039/100007307Arthrex and 10.13039/100008894Stryker. Full ICMJE author disclosure forms are available for this article online, as supplementary material., (© 2024 The Authors.)

Published
2024
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46. Diagnosis Accuracy for Compartment Syndrome: A Systematic Review and Meta-Analysis.

Author

Lorange JP, Laverdière C, Corban J, Montreuil J, and Harvey EJ

Subjects
Humans, Prospective Studies, Bayes Theorem, Lower Extremity, Leg, Compartment Syndromes diagnosis
Abstract

Objective: To evaluate whether published studies support basing the diagnosis of compartment syndrome of the lower leg on clinical findings, intracompartmental pressure (ICP) monitoring, or both., Data Sources: A PubMed/MEDLINE, Web of Science, and Embase search of the English literature from 1966 to February 2022 was performed. This used "lower extremity" or "leg" or "tibia" and "compartment syndrome" and "pressure" as the subjects. A manual search of the bibliographies was performed and cross-referenced with those used to formulate the American Academy of Orthopaedic Surgeons clinical practice guidelines., Study Selection and Extraction: Inclusion criteria were traumatic tibia injuries, presence of data to calculate the sensitivity, specificity, positive and negative predictive values of clinical findings and/or pressure monitoring, and the presence or absence of compartment syndrome as the outcome. A total of 2906 full articles were found, of which 63 were deemed relevant for a detailed review. Seven studies met all eligibility criteria., Data Synthesis: The likelihood ratio form of Bayes theorem was used to assess the discriminatory ability of the clinical findings and ICP monitoring as tests for compartment syndrome. The predictive value for diagnosing acute compartment syndrome was 21% and 29% for the clinical signs and ICP, respectively. When combining both, the probability reached 68%., Conclusions: The use of ICP monitoring may be helpful when combined with a clinical assessment to increase the sensitivity and specificity of the overall diagnosis. Previously accepted individual inference values should be revisited with new prospective studies to further characterize the statistical value of each clinical finding., Level of Evidence: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: The authors report no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Published
2023
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47. Using an Affordable Motion Capture System to Evaluate the Prognostic Value of Drop Vertical Jump Parameters for Noncontact ACL Injury.

Author

Corban J, Karatzas N, Zhao KY, Babouras A, Bergeron S, Fevens T, Rivaz H, and Martineau PA

Subjects
Humans, Case-Control Studies, Motion Capture, Prognosis, Knee Joint, Biomechanical Phenomena, Anterior Cruciate Ligament Injuries diagnosis, Anterior Cruciate Ligament Injuries etiology
Abstract

Background: Knee kinematic parameters during a drop vertical jump (DVJ) have been demonstrated to be associated with increased risk of noncontact anterior cruciate ligament (ACL) injury. However, standard motion analysis systems are not practical for routine screening. Affordable and practical motion sensor alternatives exist but require further validation in the context of ACL injury risk assessment., Purpose/hypothesis: To prospectively study DVJ parameters as predictors of noncontact ACL injury in collegiate athletes using an affordable motion capture system (Kinect; Microsoft). We hypothesized that athletes who sustained noncontact ACL injury would have larger initial and peak contact coronal abduction angles and smaller peak flexion angles at the knee during a DVJ., Study Design: Case-control study; Level of evidence, 3., Methods: 102 participants were prospectively recruited from a collegiate varsity sports program. A total of 101 of the 102 athletes (99%) were followed for an entire season for noncontact ACL injury. Each athlete performed 3 DVJs, and the data were recorded using the motion capture system. Initial coronal, peak coronal, and peak sagittal angles of the knee were identified by our software., Results: Five of the 101 athletes sustained a noncontact ACL injury. Peak coronal angles were significantly greater and peak sagittal flexion angles were significantly smaller in ACL-injured athletes ( P = .049, P = .049, respectively). Receiver operating characteristic (ROC) analysis demonstrated an area under the curve of 0.88, 0.92, and 0.90 for initial coronal, peak coronal, and peak sagittal angle, respectively. An initial coronal angle cutoff of 2.96° demonstrated 80% sensitivity and 72% specificity, a peak coronal angle cutoff of 6.16° demonstrated 80% sensitivity and 72% specificity, and a peak sagittal flexion cutoff of 93.82° demonstrated 80% sensitivity and 74% specificity on the study cohort., Conclusion: Increased peak coronal angle and decreased peak sagittal angle during a DVJ were significantly associated with increased risk for noncontact ACL injury. Based on ROC analysis, initial coronal angle showed good prognostic ability, whereas peak coronal angle and peak sagittal flexion provided excellent prognostic ability. Affordable motion capture systems show promise as cost-effective and practical options for large-scale ACL injury risk screening.

Published
2023
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48. Equation predicting tibial-tuberosity to trochlear-groove distance following supratubercle osteotomy: Radiographic proof of concept.

Author

Bozzo I, Laverdière C, Corban J, Ge S, Pauyo T, and Bernstein M

Subjects
Humans, Tibia surgery, Retrospective Studies, Tomography, X-Ray Computed, Patella, Osteotomy methods, Knee Joint, Joint Instability surgery, Patellofemoral Joint surgery
Abstract

Background: Supratubercle tibial rotational osteotomies are useful in patellar stabilizing procedures with high tibial-tuberosity to trochlear-groove distance caused by excessive external tibial torsion. An investigation determined one degree of internal tibial rotation results in 0.68 mm reduction of tibial-tuberosity to trochlear-groove distance, but did not account for anatomical variability., Methods: This is a radiographic proof of concept for equation validation. We compared two different derived equations, a complex four-variable and simplified two-variable equation, to the literature relationship and true measured value from CT imaging. Bilateral pre-operative CTs of 37 patients, evaluated for malalignment, were reviewed retrospectively. We virtually simulated derotations of five, ten and fifteen degrees, and compared the reduction in tibial-tuberosity to trochlear-groove distance measured radiologically from CTs to the one predicted by our equation., Findings: The difference between the true change in tibial-tuberosity to trochlear-groove distance and that obtained using our four-variable was statistically insignificant for all derotation angles (p > 0.05), and the two-variable equation it was statistically insignificant for five and fifteen degrees of derotation (p > 0.05). Conversely, the true values were statistically different from those found using the published relationship (p < 0.05 for all)., Interpretation: This new equation accounts for individual patient anatomy, for a more accurate relationship between internal rotation of the distal segment of the tibia and the subsequent decrease in the tibial-tuberosity to trochlear-groove distance. The change was overestimated using the linear relationship, which may result in under correction. Future studies will assess true post-operative distance change following osteotomy., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Published
2023
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49. Novel digital continuous sensor for monitoring of compartment pressure: a case report.

Author

Montreuil J, Corban J, Reindl R, Harvey EJ, and Bernstein M

Abstract

Case: The American Academy of Orthopaedic Surgeons has recently identified continuous intracompartmental pressure monitoring as 1 of the few means to assist in ruling out acute compartment syndrome (ACS). There are very few methods that allow this measurement. This manuscript describes the use of a new digital monitoring system for ACS in 3 patients. This minimally invasive device, the MY01 (NXTSENS, Montreal, Canada) is capable of continuously and precisely measuring variations in intracompartmental pressure., Conclusion: MY01 detected the occurrence of ACS at early-stage and expedited the timing of surgery for 2 patients. This tool also objectively excluded a suspected diagnosis of ACS in a medically comorbid patient, obviating the need for unnecessary fasciotomies and potential complications., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2022 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the Orthopaedic Trauma Association.)

Published
2022
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50. Augmented-reality-guided insertion of sliding hip screw guidewire: a preclinical investigation.

Author

Laverdière C, Corban J, Ge S, Kang Y, Harvey E, Martineau PA, Noel G, and Reindl R

Subjects
Bone Screws, Fluoroscopy, Humans, Augmented Reality, Hip Fractures diagnostic imaging, Hip Fractures surgery, Surgery, Computer-Assisted methods
Abstract

Background: The sliding hip screw (SHS) is frequently used in the management of hip fractures; successful placement depends on accurate positioning of the lag screw in the femoral head guided by fluoroscopy. We proposed to leverage the capabilities of augmented reality (AR) to overlay virtual images of the desired guidewire trajectory directly onto the surgical field to guide the surgeon during SHS guidewire insertion., Methods: Using a commercially available AR headset and software, we performed preprocedural planning using computed tomography scans to identify the optimal trajectory for SHS guidewire insertion in the neck of a Sawbones femur model. The images of the scanned femurs containing the virtual guidewire trajectory were overlaid on the physical models such that the user could see a composite view of the computer-generated images and the physical environment. Two second-year orthopedic residents each inserted 15 guidewires under AR guidance and 15 guidewires under fluoroscopy., Results: Of the 30 guidewires inserted under AR guidance, 24 (80%) were within the femoral neck, and 16 (53%) were fully enclosed within the femoral head. Nine (56%) of the 16 perforations were due to insertions that were too far along the planned trajectory. Thirteen (81%) of the successful attempts with AR had an appropriate position, compared to 25/26 (96%) with fluoroscopy. It took significantly less time to perform the procedure using fluoroscopy than AR ( p < 0.05). Fluoroscopy required on average 18.7 shots., Conclusion: Augmented reality provides an opportunity to aid in guidewire insertion in a preplanned trajectory with less radiation exposure in a sterile environment, but technical challenges remain to be solved to enable widespread adoption., Competing Interests: Competing interests: Edward Harvey reports grants or contracts from the Canadian Institutes of Health Research (CIHR), the US Department of Defense and the Natural Sciences and Engineering Research Council of Canada. He holds dozens of patents for orthopedic devices and methods outside the submitted work. He has participated on a CIHR institute advisory board, and has played a leadership role for the Orthopaedic Trauma Association. He holds stock in MY01 and NXTSENS Microsystems. He is also coeditor-in-chief of CJS; he was not involved in the review of this manuscript nor in the decision to accept it for publication. No other competing interests were declared., (© 2022 CMA Impact Inc. or its licensors.)

Published
2022
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