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Biomedical subjects

K Kedzior

Publications and source records attributed to K Kedzior.

8 recordsLinked to original sources
PubMed2001

The anatomic features of the radial head and their implication for prosthesis design.

OBJECTIVE: To establish the anatomical features of the radial head of an average normal human being and to verify the hypothesis that no significant difference exists between the geometry of the left and right normal radial heads. DESIGN: 17 proximal ends of the radius from the left and right forearms of fresh male (average age 50 and range 40-70) cadavers were measured. BACKGROUND: A reconstruction of anatomical features of the normal bone is important for prosthesis design. METHODS: A morphologic study of the radial head was performed using a co-ordinate measuring machine integrated with a computer aided design system. For comparative purposes, a statistical analysis including linear regression and correlation was performed. RESULTS: The maximum diameter (mean 23.36 mm (SD, 1.14 mm)) and height (mean 10.14 mm (SD, 1.38 mm)) of the radial head as well as the depth (mean 1.92 mm (SD, 0.32 mm)) and maximum radius (mean 20.27 mm (SD, 4.61 mm)) of the concave articulate surface are the most important anatomical features, which should be implicated in prosthesis design. The inclinations mean 2.50 degrees (SD, 0.41 degrees ) and mean 9.50 degrees (SD, 0.52 degrees ) and shift (mean 1.71 mm (SD, 0.35 mm)) of the radial head relative to its neck should also be taken into account in prosthetic design. CONCLUSIONS: The results of the study showed that "left is equal to right" (no significant differences between sides were obtained, for probability value P>0.05). RELEVANCE: This paper describes a morphological study of the proximal radius. The results can be used to reconstruct the geometry of the injured radial head based on the obtained geometric features of the contra-lateral side. These results can be also used to design radial head prosthesis.

Adult↗
PubMed1999

The potential role of brain asymmetry in the development of adolescent idiopathic scoliosis: a hypothesis.

BACKGROUND: The size asymmetry of cerebral hemispheres may predispose to head tilt and asymmetric blocking of the zygapophysial joints, potentially leading to the development of compensatory curvatures in the lower segments of the spine. OBJECTIVE: To analyze the effects of spinal manipulation, maintained by an exercise program, on the progression of idiopathic adolescent scoliosis in 2 children aged 6 and 10. CLINICAL FEATURE: The scoliosis found was 16 and 60 degrees. INTERVENTION AND OUTCOME: For diagnosis and monitoring of therapy, we recorded qualitative parameters of shoulder asymmetry, axillary line asymmetry, and scapular angle position. Manual treatment consisted of the examinations of all sliding motion in zygapophysial joints and both sacroiliac joints and removing the limitations of the sliding motions according to the method of Karel Lewit. The treatment procedure consisted of 3 or 4 manipulations within 17 months and an exercise program. The manipulation effects were maintained by the exercise program. The exercises were done in 2 or 3 sessions weekly for a year. In both patients we observed that scoliosis decompensation was successfully stopped and the effects of the correction persisted for 10 years. CONCLUSION: Brain and head asymmetry may be only a transient state, predisposing to asymmetric blocking at the atlanto-occipital level. Removal of blocking may prevent curve progression in children who had adolescent idiopathic scoliosis. The manipulative therapy may also have a promising effect on retarding curve progression when used in skeletally immature patient.

Brain↗
PubMed1999

Computerized method for work space optimization in conditions of static work.

The aim of this research was to develop a theoretical method for the ergonomic optimization of the work space of the upper limb. This method is based on a model of the upper extremity with 7 degrees of freedom. It consists of 3 rigid elements modeling the arm, forearm, and hand and 34 upper extremity muscles. The trunk is considered immobile. The shoulder joint is modeled as a rotating kinematics pair of third class, the elbow and wrist joints--of fourth class. The minimum sum of muscle force moments in the joints and soft saturation muscle cooperation criterion were used as merit criteria. The developed method makes it possible to effectively solve, in a defined work space, the task of work space optimization.

Arm↗
PubMed1999

Experimental verification of the computerized method for work space optimization in conditions of static work.

The aim of this study was to verify a theoretical model for upper extremity work space optimization. In order to do that, experimental studies were conducted in which two parameters of the electromyography (EMG) signal were analyzed: AMP (amplitude calculated as Root Mean Square) and SZC (coefficient of the slope of the regression line between time and Zero Crossing values). Values of forces in muscles (parameter MOD) were calculated from theoretical studies. A comparison of experimental (AMP, SZC) and theoretical (MOD) parameters was performed by analyzing the coefficient of correlation between those parameters and differentiation of muscular load according to external load value. Analysis showed that the theoretical and experimental results are in step, which means that the developed model can be used for upper extremity work space optimization.

Adult↗
PubMed1992

Non-linear finite element analysis of formation and treatment of intervertebral disc herniae.

A biomechanical model of the spine motion segment L2/L3 consisting of the truncated vertebrae, endplates, intervertebral disc and pieces of anterior and posterior longitudinal ligaments has been used for a computer simulation study. A non-linear finite element analysis has shown that small loads compressing the spine, not greater than those occurring in everyday life, cause loss of stability of an intervertebral disc, resulting in lateral dislocation of its nucleus pulposus. This could be a potential cause of discopathy. The model indicates that conservative therapy of herniated disc by the traction method may result in retraction of hernia by about 40 per cent.

Biomechanical Phenomena↗
PubMed1991

A biomechanical model of the human spinal system.

An experimental study of spinal biomechanics both in vivo and in vitro is difficult and often not reliable enough. The mathematical modelling and computer simulation approach is one that can be successfully applied. Modelling in this case is difficult due to the very complicated, heterogeneous nature of the object under investigation. The paper presents a biomechanical model of the spine system consisting of the spinal column (vertebrae, discs), ligaments, muscles directly and indirectly acting on the spinal column, as well as the rib-cage, abdomen and part of the pelvis. The finite element method combined with the optimization approach has been used for modelling. Typical results of these investigations are presented.

Biomechanical Phenomena↗