Snapshot of training/testing code along with documentation of the organization within each HDF5 d... more Snapshot of training/testing code along with documentation of the organization within each HDF5 data file.
This collection contains data and code associated with the IPCAI/IJCARS 2020 paper "Automati... more This collection contains data and code associated with the IPCAI/IJCARS 2020 paper "Automatic Annotation of Hip Anatomy in Fluoroscopy for Robust and Efficient 2D/3D Registration." The data hosted here consists of annotated datasets of actual hip fluoroscopy, CT and derived data from six lower torso cadaveric specimens. Documentation and examples for using the dataset and Python code for training and testing the proposed models are also included. Higher-level information, including clinical motivations, prior works, algorithmic details, applications to 2D/3D registration, and experimental details, may be found in the companion paper which is available at https://arxiv.org/abs/1911.07042 or https://doi.org/10.1007/s11548-020-02162-7. We hope that this code and data will be useful in the development of new computer-assisted capabilities that leverage fluoroscopy.
Medical Imaging 2018: Image-Guided Procedures, Robotic Interventions, and Modeling
Proper implant alignment is a critical step in total hip arthroplasty (THA) procedures. In curren... more Proper implant alignment is a critical step in total hip arthroplasty (THA) procedures. In current practice, correct alignment of the acetabular cup is verified in C-arm X-ray images that are acquired in an anteriorposterior (AP) view. Favorable surgical outcome is, therefore, heavily dependent on the surgeon’s experience in understanding the 3D orientation of a hemispheric implant from 2D AP projection images. This work proposes an easy to use intra-operative component planning system based on two C-arm X-ray images that is combined with 3D augmented reality (AR) visualization that simplifies impactor and cup placement according to the planning by providing a real-time RGBD data overlay. We evaluate the feasibility of our system in a user study comprising four orthopedic surgeons at the Johns Hopkins Hospital, and also report errors in translation, anteversion, and abduction as low as 1.98 mm, 1.10°, and 0.53°, respectively. The promising performance of this AR solution shows that deploying this system could eliminate the need for excessive radiation, simplify the intervention, and enable reproducibly accurate placement of acetabular implants.
L'invention porte sur un module lumineux a diode electroluminescente amovible destine a etre ... more L'invention porte sur un module lumineux a diode electroluminescente amovible destine a etre utilise dans un ensemble d'eclairage, lequel module comprend un element d'eclairage a diode electroluminescente et un ou plusieurs elements elastiques concus pour maintenir une force de compression entre le module lumineux a diode electroluminescente et une douille et/ou un element de dissipation de chaleur ou un boitier thermiquement conducteur afin d'assurer un transfert de chaleur efficace de la diode electroluminescente vers l'element de dissipation de chaleur ou le boitier thermiquement conducteur. Un ou plusieurs elements de contact electrique du module lumineux a diode electroluminescente sont configures de facon a venir en contact de facon liberable avec un ou plusieurs elements de contact electrique d'une douille de l'ensemble d'eclairage lorsque le module lumineux a diode electroluminescente est couple a la douille afin d'etablir une connexion el...
Background Conflicting results about the impact of blood transfusions on outcomes after total kne... more Background Conflicting results about the impact of blood transfusions on outcomes after total knee arthroplasty (TKA) have been reported. We hypothesized that transfusions would be associated with greater readmission and complication rates after primary TKA. Methods We conducted a retrospective cohort study of the 100% 2008 Medicare Provider Analysis and Review database, and identified primary THA patients by ICD9 codes and excluded fractures/ER admissions to select for elective cases. Patients who received a perioperative blood transfusion (6,951 patients) were compared to a control group who did not receive transfusion (332,762 patients). Descriptive statistics of age, sex, race, diagnosis for surgery, Elixhauser comorbidities, mortality (inpatient, 30, 60, and 90 days and 2 years), readmissions (30, 60, and 90 days), complications (medical and surgical at 30 and 90 days), and revision at 2 years were assessed for both groups. Continuous variables were compared with Student's ...
L'invention concerne un ensemble d'eclairage et un procede pour fabriquer un ensemble d&#... more L'invention concerne un ensemble d'eclairage et un procede pour fabriquer un ensemble d'eclairage. L'ensemble d'eclairage comprend un module lumineux comprenant un element d'eclairage, et une enceinte ayant un evidement pour recevoir et loger le module lumineux. L'ensemble d'eclairage comprend egalement un noyau thermiquement conducteur relie au module lumineux a travers l'enceinte. L'ensemble d'eclairage comprend en outre un boitier monte en contact thermique avec le noyau et l'enceinte, afin d'amener le boitier a dissiper la chaleur vers l'atmosphere ambiante.
Journal of medical imaging (Bellingham, Wash.), 2018
Reproducibly achieving proper implant alignment is a critical step in total hip arthroplasty proc... more Reproducibly achieving proper implant alignment is a critical step in total hip arthroplasty procedures that has been shown to substantially affect patient outcome. In current practice, correct alignment of the acetabular cup is verified in C-arm x-ray images that are acquired in an anterior-posterior (AP) view. Favorable surgical outcome is, therefore, heavily dependent on the surgeon's experience in understanding the 3-D orientation of a hemispheric implant from 2-D AP projection images. This work proposes an easy to use intraoperative component planning system based on two C-arm x-ray images that are combined with 3-D augmented reality (AR) visualization that simplifies impactor and cup placement according to the planning by providing a real-time RGBD data overlay. We evaluate the feasibility of our system in a user study comprising four orthopedic surgeons at the Johns Hopkins Hospital and report errors in translation, anteversion, and abduction as low as 1.98 mm, 1.10 deg, ...
The Journal of bone and joint surgery. American volume, Jan 7, 2017
In April 2016, the U.S. Centers for Medicare & Medicaid Services initiated mandatory 90-day bundl... more In April 2016, the U.S. Centers for Medicare & Medicaid Services initiated mandatory 90-day bundled payments for total hip and knee arthroplasty for much of the country. Our goal was to determine duration of care, 90-day charges, and readmission rates by discharge disposition and U.S. region after hip or knee arthroplasty. Using the 2008 Medicare Provider Analysis and Review database 100% sample, we identified patients who had undergone elective primary total hip or knee arthroplasty. We collected data on patient age, sex, comorbidities, U.S. Census region, discharge disposition, duration of care, 90-day charges, and readmission. Multivariate regression was used to assess factors associated with readmission (logistic) and charges (linear). Significance was set at p < 0.01. Patients undergoing 138,842 total hip arthroplasties were discharged to home (18%), home health care (34%), extended-care facilities (35%), and inpatient rehabilitation (13%); patients undergoing 329,233 total ...
Snapshot of training/testing code along with documentation of the organization within each HDF5 d... more Snapshot of training/testing code along with documentation of the organization within each HDF5 data file.
This collection contains data and code associated with the IPCAI/IJCARS 2020 paper "Automati... more This collection contains data and code associated with the IPCAI/IJCARS 2020 paper "Automatic Annotation of Hip Anatomy in Fluoroscopy for Robust and Efficient 2D/3D Registration." The data hosted here consists of annotated datasets of actual hip fluoroscopy, CT and derived data from six lower torso cadaveric specimens. Documentation and examples for using the dataset and Python code for training and testing the proposed models are also included. Higher-level information, including clinical motivations, prior works, algorithmic details, applications to 2D/3D registration, and experimental details, may be found in the companion paper which is available at https://arxiv.org/abs/1911.07042 or https://doi.org/10.1007/s11548-020-02162-7. We hope that this code and data will be useful in the development of new computer-assisted capabilities that leverage fluoroscopy.
Medical Imaging 2018: Image-Guided Procedures, Robotic Interventions, and Modeling
Proper implant alignment is a critical step in total hip arthroplasty (THA) procedures. In curren... more Proper implant alignment is a critical step in total hip arthroplasty (THA) procedures. In current practice, correct alignment of the acetabular cup is verified in C-arm X-ray images that are acquired in an anteriorposterior (AP) view. Favorable surgical outcome is, therefore, heavily dependent on the surgeon’s experience in understanding the 3D orientation of a hemispheric implant from 2D AP projection images. This work proposes an easy to use intra-operative component planning system based on two C-arm X-ray images that is combined with 3D augmented reality (AR) visualization that simplifies impactor and cup placement according to the planning by providing a real-time RGBD data overlay. We evaluate the feasibility of our system in a user study comprising four orthopedic surgeons at the Johns Hopkins Hospital, and also report errors in translation, anteversion, and abduction as low as 1.98 mm, 1.10°, and 0.53°, respectively. The promising performance of this AR solution shows that deploying this system could eliminate the need for excessive radiation, simplify the intervention, and enable reproducibly accurate placement of acetabular implants.
L'invention porte sur un module lumineux a diode electroluminescente amovible destine a etre ... more L'invention porte sur un module lumineux a diode electroluminescente amovible destine a etre utilise dans un ensemble d'eclairage, lequel module comprend un element d'eclairage a diode electroluminescente et un ou plusieurs elements elastiques concus pour maintenir une force de compression entre le module lumineux a diode electroluminescente et une douille et/ou un element de dissipation de chaleur ou un boitier thermiquement conducteur afin d'assurer un transfert de chaleur efficace de la diode electroluminescente vers l'element de dissipation de chaleur ou le boitier thermiquement conducteur. Un ou plusieurs elements de contact electrique du module lumineux a diode electroluminescente sont configures de facon a venir en contact de facon liberable avec un ou plusieurs elements de contact electrique d'une douille de l'ensemble d'eclairage lorsque le module lumineux a diode electroluminescente est couple a la douille afin d'etablir une connexion el...
Background Conflicting results about the impact of blood transfusions on outcomes after total kne... more Background Conflicting results about the impact of blood transfusions on outcomes after total knee arthroplasty (TKA) have been reported. We hypothesized that transfusions would be associated with greater readmission and complication rates after primary TKA. Methods We conducted a retrospective cohort study of the 100% 2008 Medicare Provider Analysis and Review database, and identified primary THA patients by ICD9 codes and excluded fractures/ER admissions to select for elective cases. Patients who received a perioperative blood transfusion (6,951 patients) were compared to a control group who did not receive transfusion (332,762 patients). Descriptive statistics of age, sex, race, diagnosis for surgery, Elixhauser comorbidities, mortality (inpatient, 30, 60, and 90 days and 2 years), readmissions (30, 60, and 90 days), complications (medical and surgical at 30 and 90 days), and revision at 2 years were assessed for both groups. Continuous variables were compared with Student's ...
L'invention concerne un ensemble d'eclairage et un procede pour fabriquer un ensemble d&#... more L'invention concerne un ensemble d'eclairage et un procede pour fabriquer un ensemble d'eclairage. L'ensemble d'eclairage comprend un module lumineux comprenant un element d'eclairage, et une enceinte ayant un evidement pour recevoir et loger le module lumineux. L'ensemble d'eclairage comprend egalement un noyau thermiquement conducteur relie au module lumineux a travers l'enceinte. L'ensemble d'eclairage comprend en outre un boitier monte en contact thermique avec le noyau et l'enceinte, afin d'amener le boitier a dissiper la chaleur vers l'atmosphere ambiante.
Journal of medical imaging (Bellingham, Wash.), 2018
Reproducibly achieving proper implant alignment is a critical step in total hip arthroplasty proc... more Reproducibly achieving proper implant alignment is a critical step in total hip arthroplasty procedures that has been shown to substantially affect patient outcome. In current practice, correct alignment of the acetabular cup is verified in C-arm x-ray images that are acquired in an anterior-posterior (AP) view. Favorable surgical outcome is, therefore, heavily dependent on the surgeon's experience in understanding the 3-D orientation of a hemispheric implant from 2-D AP projection images. This work proposes an easy to use intraoperative component planning system based on two C-arm x-ray images that are combined with 3-D augmented reality (AR) visualization that simplifies impactor and cup placement according to the planning by providing a real-time RGBD data overlay. We evaluate the feasibility of our system in a user study comprising four orthopedic surgeons at the Johns Hopkins Hospital and report errors in translation, anteversion, and abduction as low as 1.98 mm, 1.10 deg, ...
The Journal of bone and joint surgery. American volume, Jan 7, 2017
In April 2016, the U.S. Centers for Medicare & Medicaid Services initiated mandatory 90-day bundl... more In April 2016, the U.S. Centers for Medicare & Medicaid Services initiated mandatory 90-day bundled payments for total hip and knee arthroplasty for much of the country. Our goal was to determine duration of care, 90-day charges, and readmission rates by discharge disposition and U.S. region after hip or knee arthroplasty. Using the 2008 Medicare Provider Analysis and Review database 100% sample, we identified patients who had undergone elective primary total hip or knee arthroplasty. We collected data on patient age, sex, comorbidities, U.S. Census region, discharge disposition, duration of care, 90-day charges, and readmission. Multivariate regression was used to assess factors associated with readmission (logistic) and charges (linear). Significance was set at p < 0.01. Patients undergoing 138,842 total hip arthroplasties were discharged to home (18%), home health care (34%), extended-care facilities (35%), and inpatient rehabilitation (13%); patients undergoing 329,233 total ...
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Papers by Clayton Alexander