ABSTRACT
El dolor facetario lumbar es una de las principales causas de dolor lumbar; representa alrededor del 15-56%. La articulación facetaria estabiliza la columna vertebral, tiene un rol fundamental en el soporte, distribución del peso y regulación de los movimientos rotacionales de la columna. Por ello, el conocimiento de la anatomía y de la biomecánica de esta articulación ayuda a tener una mejor comprensión de su participación en la fisiopatología del dolor lumbar y, por ende, mejora su abordaje diagnóstico y terapéutico. Nosotros revisamos aquí los conceptos actuales de embriología, anatomía, biomecánica y la correlación clínica/imagenológica de los cambios asociados a la enfermedad degenerativa facetaria de la columna lumbar.
Low back pain is a very common reason for emergency room consultation, it is found in approximately 60% of adults, and, within it, facet lumbar pain is one of the main causes, accounting for about 15-56% of low back pain cases. The facet joint stabilizes the spine, helps to distribute loads and has a fundamental role in support, weight distribution, and rotational movements regulation of the spine. Consequently, knowledge of the anatomy and biomechanics of this joint is helpful to have a better understanding of their contribution to the low back pain pathophysiology and, therefore, improving diagnostic and therapeutic approaches. This paper aims to review the current concepts of embryology, anatomy, biomechanics, and clinical/imaging correlation of the changes associated with lumbar degenerative facet disease
Subject(s)
Humans , Low Back Pain , Osteoarthritis , Spine , Anatomy , JointsABSTRACT
Objective To conduct dynamic impact failure test of rabbit single vertebra, and make comparison with the static compression experiment, so as to study damage mechanism of the vertebral body under the axial impact. Methods The voltage waveform diagram of the force sensor and the detailed process of the vertebral impact were obtained by the oscilloscope and high-speed photography through the drop hammer dynamic impact experimental device. Results The average static load of the thoracic and lumbar vertebra were 910 N and 947 N, respectively; the average dynamic load of the thoracic and lumbar vertebra were 1 196 N and 1 026 N, respectively; the average thoracic and lumbar dynamic load coefficients were 1.37 and 1.08; under static load, the average stress of the thoracic and lumbar vertebra was 15.28 MPa and 12.51 MPa, respectively; under dynamic load, the average stress of the thoracic and lumbar vertebra was 20.03 MPa and 13.56 MPa; during dynamic impact, the mean longitudinal strain and transverse strain was -0.3 and -0.005 (compression); under dynamic conditions, the destruction energy of vertebrae increased from 0 J to 4.4 J. Conclusions Under dynamic and static experimental conditions, the dynamic load of the same vertebral body was greater than that of the static load; the average dynamic load coefficient of the thoracic vertebra was larger than that of the lumbar vertebra; the equivalent stress of the thoracic vertebra was greater than that of the lumbar vertebra; the axial strain of vertebra under impact was greater than the transverse strain; energy growth of the vertebral body presented a slow at first and then a rapid changing process. The research findings can provide some guidance for prevention and rehabilitation of human vertebral body injury in clinic.
ABSTRACT
Objective To discuss the mechanostat of bone remodeling under dynamic loads. Methods By analysis on mechanostat of bone remodeling and absorption from the idea of mechanical fatigue strength theory, the mechanostat of bone remodeling under dynamic loads was developed. Damage was selected as the mechanical stimulus under dynamic loads and the model of bone remodeling under dynamic loads was proposed. Physical exercise for prevention and treatment of osteoporosis was simulated to analyze the biomechanical phenomenon why the osteogenesis effect under dynamic loads seems better than that under static loads. Results The biomechanical phenomenon as mentioned above was reasonably explained. An increase of 10%-30% in physical exercise could cause an increase of 3.13%-8.61% in bone mineral density. Conclusions The mechanostat of bone remodeling under dynamic loads will provide theoretical guidance for using mechanical vibration to treat or prevent diseases related to bone metabolism, which is the supplement and improvement for mechanostat of bone remodeling.
ABSTRACT
Objective To study the failure tolerance in long bones of lower limbs under dynamic loads. Methods Based on the finite element (FE) model of lower limb for Chinese people, the dynamic three-point bending test on the femur, tibia, leg and thigh was conducted , and the FE model was validated against the cadaveric experiment. Results The force-displacement curves between FE simulation and cadaveric experimental results for bending tests were correlated. The contact forces on femur, tibia, thigh and leg with failure tolerance were 4.29, 3.94, 4.81 and 4.086 kN, respectively，and the displacements from the impactor were 17.78, 34, 52.1, and 47.06 mm, respectively. The simulation results were correlated well with those in dynamic cadaveric experiments. Conclusions This study validated the effectiveness of the FE model, which would lay a good foundation for the further research on validation of FE model of knee joint and whole lower limb, and provide the theoretical references for the protection of pedestrians in crashes.
ABSTRACT
The various biomechanical responses such as stress distribution, facet contact force and nucleus pressure change in the lumbar spine under vertical static and dynamic loading conditions were. Investigated with a nonlinear three dimensional finite element model. Finite element model of one motion segment, consisted of two vertebral bodies(L3-4) with one disc, was developed from 1 mm thick transverse CT cross-sections. Geometrical nonlinearity was also considered for the large deformation on the disc. ABACUS package was used for calculation and its results were verified comparing with the existing in-vitro experimental data. Clinically useful results could be obtained with this analysis. Stress was concentrated on the endplate under static and dynamic loading condition, especially posterior and anterior aspect and central portion along midsagittal plane. The facet contact force showed some discontinuity when Δt/2=0.03 sec. This discontinuity was considered to de due to the vibration of upper vertebra. Relatively smooth contact force profile was detected when t/2=0.1342 sec. Intradiscal pressure and stress pattern changes on the vertebra were also analyzed.