A note on some identification problems arising in roentgen stereo photogrammetric analysis

Nyström, Leif; Söderkvist, Inge; Wedin, Per-Åke

doi:10.1016/0021-9290(94)90283-6

Cited by 23 publications

(8 citation statements)

References 5 publications

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“…These cages are based on the same laboratory system, but cage 77 is modified to allow better visualization of cage markers when the cage is attached to film‐switchers. Marker scattering and stability was documented using the condition number (CN) and the mean error of rigid body fitting (ME) . In the evaluation of abduction, the median (range) CN varied between 43 (35–46), 49 (20–150), and 79 (23–90) for the femoral, acetabular, and cup markers, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…Marker scattering and stability was documented using the condition number (CN) 10 and the mean error of rigid body fitting (ME). 11,12 In the evaluation of abduction, the median (range) CN varied between 43 (35-46), 49 (20-150), and 79 (23-90) for the femoral, acetabular, and cup markers, respectively. The corresponding median (range) mean errors (ME) were 0.08 (0.07-0.20), 0.24 (0.11-0.34), and 0.23 (0.14-0.33).…”

Section: Cemented Total Hip Replacementsmentioning

confidence: 99%

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Inducible displacements of the cup and the femoral head during active range of motion: Dynamic RSA studies of cemented total hip replacements

Digas¹,

Johansson

Kärrholm

2013

Journal Orthopaedic Research

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We evaluated changes in position of the femoral head relative to the cup and of the cup relative to the pelvis in total hip replacement patients during hip motion 2 years postoperatively. Two patient groups with nine patients in each group were studied. Hip motions, translations of the femoral head center, and cup displacements were recorded with dynamic radiostereometric examination (RSA, 2 exposures/s) during abduction in Group 1 and with use of static RSA exposures at increasing flexion of the hip in Group 2. Conventional radiographic examinations were used to evaluate any radiolucent lines around the cups at 2 years. During active abduction the femoral head center moved medially (median 0.04 mm) and the cup tilted anteriorly (median 0.09 mm). Increments in radiolucent lines at 2 years correlated to medial femoral head penetration, posterior tilt, and retroversion of the cup at 20˚of abduction. The extension of radiolucent lines at 2 years showed a positive correlation with proximal inducible displacement of the cup and posterior translation of the femoral head center at maximum hip flexion. Our observations may be of value in understanding the pathogenesis of the loosening process and may be used to facilitate the development of prosthetic designs that optimize hip kinematics. ß

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Section: Methodsmentioning

confidence: 99%

Section: Cemented Total Hip Replacementsmentioning

confidence: 99%

Inducible displacements of the cup and the femoral head during active range of motion: Dynamic RSA studies of cemented total hip replacements

Digas¹,

Johansson

Kärrholm

2013

Journal Orthopaedic Research

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“…The RSA method has been continuously developed to improve its applicability in different fields of orthopaedic research (Kärrholm 1989, Söderqvist and Wedin 1993, Nyström et al 1994, Börlin 1997, Kärrhohn et al 1997, and Vrooman et al 1998. During the late twentieth century manual measurements of RSA radiographs were gradually replaced by digital measurements.…”

Section: Control Pointsmentioning

confidence: 99%

New polymer materials in total hip arthroplasty

Digas¹

2005

Acta Orthopaedica

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“…These techniques are mostly based on the direct linear transformation (DLT) algorithm [1], optimized [18] or modified [2,4,6,11,12,21,22], making it possible to reconstruct a point using its projections on two X-ray films. Although quite accurate on the vertebral body of non-pathological vertebrae, these techniques are far from being optimal on scoliotic vertebrae [3,20], because of the lack of identifiable stereo-corresponding points in certain vertebral regions, e.g., the posterior arch.…”

Section: A Mitulescu W Skalli D Mitton J a De Guisementioning

confidence: 99%

Three-dimensional surface rendering reconstruction of scoliotic vertebrae using a non stereo-corresponding points technique

et al. 2002

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IntroductionAs scoliosis is a three-dimensional (3D) local and global deformation of the spine [5,9,10,23], 3D computerized rendering of scoliotic vertebrae is required for surgical planning as well as for finite element modeling of this spinal pathology [3,16].Because of the high irradiating dose [17] and of the patient having to adopt a lying position, computed tomography (CT), although quite accurate [7, 14,20], is an inappropriate 3D reconstruction method when dealing with scoliotic patients. Thus alternative radiological 3D reconstruction techniques, using 3D surface rendering algorithms, are necessary in order to provide the surgeon with the same 3D information. Such alternative techniques are all based on the stereoradiography method, which is also called biplanar radiography.Stereoradiographic 3D reconstruction techniques are divided into two classes. The first of these use an algorithm that allows reconstruction only where there are stereo-corresponding points, i.e., points for which the proAbstract The medical imaging techniques that allow a three-dimensional (3D) surface rendering reconstruction, which is usually required by the clinician when dealing with scoliotic patients, are computed tomography (CT) and stereoradiography. However, CT cannot provide a 3D rendering of the whole spine because of the high irradiating dose, while the stereoradiographic 3D reconstruction techniques, which use an algorithm derived from the direct linear transformation (DLT), are usually limited in accuracy because of the small number of corresponding anatomical landmarks identifiable on both radiographs. The purpose of the present study is to validate a recent biplanar 3D surface rendering reconstruction technique on scoliotic vertebrae. This technique, called "non stereo-corresponding points" (NSCP), has already been tested on non-pathologic dry cervical vertebrae and frozen lumbar specimens, and the results have proved very encouraging. Since scoliosis is a 3D deformity of the vertebrae and of the global spine, such a technique could be a very useful clinical tool for the diagnostic, follow-up and surgical planning when dealing with scoliotic patients. The validation of the NSCP technique on scoliotic patients was performed on 58 scoliotic vertebrae in 14 patients, by comparison with the CT scan 3D rendering technique. The results of this study show mean errors of 1.5 mm. On the basis of this study, we can conclude that the NSCP 3D reconstruction technique is a definite improvement over existing techniques, and can serve as a useful diagnosis tool in scoliosis. However, the results of the technique still need to be optimized for use in geometrical modeling.

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A note on some identification problems arising in roentgen stereo photogrammetric analysis

Cited by 23 publications

References 5 publications

Inducible displacements of the cup and the femoral head during active range of motion: Dynamic RSA studies of cemented total hip replacements

Inducible displacements of the cup and the femoral head during active range of motion: Dynamic RSA studies of cemented total hip replacements

New polymer materials in total hip arthroplasty

Three-dimensional surface rendering reconstruction of scoliotic vertebrae using a non stereo-corresponding points technique

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