Biomechanics and classification of traumatic lesions of the spine.
Explore the source record for details and available documents.
Biomechanical Phenomena↗
Biomedical subjects
M Guillot
Publications and source records attributed to M Guillot.
Preliminary study of the human lumbar spine using speckle technique. Limits of compression, shear and torsion. Speckle photography--electronic speckle pattern interferometry.
Optical techniques using single wavelength lasers allow precise study of the superficial displacements of deeper anatomical structures through direct mechanical pull. Two techniques have been used in this study: 1. Double exposure speckle photography. Since 1980 the relationship between the surface displacements and minimal traction applied to the transverse processes of the spine, either unilateral or bilateral, was studied in an attempt to simulate muscular action exerted at this level. 2. Computerised speckle interferometry. This allowed analysis of the deformations between the lumbar vertebrae under vertical compression, shear or torsion outside the usual anatomical planes. This preliminary study outlines the mechanical behaviour and the plasticity of the vertebral structures but has been performed on only a few anatomical specimens thus not allowing statistical analysis. This would require a larger series.
Biomechanical Phenomena↗
A model of the human lumbar vertebral column: a preliminary study.
Finite element modelling of the human lumbar vertebral column employs data-processing procedures for study of the linear and nonlinear elasticity of materials such as are currently used in mechanics or in civil engineering. Thanks to developments in computer science, requiring a close collaboration between doctors and engineers, we put forward in this preliminary study a linear computerised model of the lumbar column comprising 4824 meshes and 6813 nodes. By reducing the simplificatory hypotheses and integrating new parameters, this model as developed is capable of important clinical applications in surgery and ergonomics.
Computer Graphics↗
A method for the evaluation of tensile properties of skin equivalents.
In vitro production of anchored skin equivalent is a new therapeutical option for burn patients. A skin equivalent is a combined culture of dermal and epidermal layers. The dermal layer provides important mechanical properties, such as tensile resistance and nonlinear elasticity, to the skin equivalent during its development. Prior to any in vivo human transplantation, the tensile properties of cutaneous equivalents have to be evaluated as a function of its structural components, in view of establishing the culture conditions leading to the best mechanical resistance and stretchability characteristics. However, the handling and clamping of skin equivalents are frequent causes of tearing and lack of repeatability in the measuring of tensile properties. A new indentation method involving a specially designed culture dish has been developed to minimize the risk of damage. Using this new culture dish, cutaneous equivalents were installed on an indentation apparatus. The central loading of a spherical tip was transmitted to the central area of a circular anchored cutaneous equivalent and was recorded with tip position. The tests were achieved at a constant low deflection rate of the tip. This new and accurate method gave repeatability in three central load-deflection characteristics of anchored dermal equivalent: the high-modulus (0.15 g mm-1), the central load of rupture (1.49 g), the rupture deflection (0.470 mm). This indentation test is expected to be an efficient tool in the evaluation of various skin equivalent models tensile properties.
Biological Dressings↗
Deletions of both alpha 5(IV) and alpha 6(IV) collagen genes in Alport syndrome and in Alport syndrome associated with smooth muscle tumours.
Diffuse oesophageal leiomyomatosis (DL), an inherited smooth muscle proliferation process, has been reported to be associated with Alport syndrome (AS), a familial nephropathy, mainly dominant X-linked inherited, and characterized by ultrastructural changes of the glomerular basement membrane. The COL4A5 gene, encoding the alpha 5 chain of type IV collagen, has been identified as the site of mutations in families with X-linked AS. Recently, a novel alpha 6(IV) collagen chain encoding gene has been mapped closely upstream of COL4A5, and disruption of the 5' end of both genes has been reported in four patients with DL and AS (DL-AS). Here, we report a long-range restriction map around the COL4A6 locus, and show that the COL4A5/COL4A6 deletion observed in seven patients with DL-AS encompasses only the two first exons of COL4A6, with a breakpoint located in the second intron of COL4A6, whose size exceeds 65 kb. Furthermore, we demonstrate that three patients with AS without DL, known to have a deletion of the 5' part of the COL4A5 gene, display a larger deletion in COL4A6. Moreover, a COL4A6 mRNA product was detected by reverse-transcription-polymerase chain reaction in an oesophageal tumour sample of a patient with DL-AS. These results suggest that DL-AS could be caused by an abnormal truncated alpha 6(IV) chain.
Adolescent↗
[The intervertebral disk. Attempt at a "finite element" model].
Intervertebral disk composite model is unsatisfactory definite in biomechanical behaviour despite multiples technics used. Using histologic and histoenzymology it's possible to determinate proportions of collagen fibers in the different parts of the disk. A trustworthy finite element 3D model is proposed and tried by real experiments.
Biomechanical Phenomena↗
Preliminary opto-electronic study on vertebral movement.
Opto-electronic systems utilising measurement of displacement of skin markers allows study of movement in the living subject. The authors have used this method in a kinematic study of the thoracic and lumbar spine measuring the displacement of skin markers placed over the spinous processes. It was possible to approach the physiological state of these complex movements once the apparatus had been calibrated to the correct level, and the error margins minimised. Repeated measurements confirmed the reliability of this method even if movement of the skin with respect to the bony reference points introduced some margin of error. Three dimensional displacement of the vertebrae were measured during voluntary movements of the spine demonstrating the complex geometry. Since opto-electronics are non-invasive they constitute an important advance in the study of the kinematics of the spine.
Adult↗
Mechanisms of orientation of the pelvifemoral base during static loading of the lumbar spine in weight-lifters.
Under static loading during weight-lifting, the lumbosacral spine essentially exhibits horizontalisation of the base of the sacrum (superior plateau of S1). We have attempted to elicit the mechanism of this horizontalisation by means of radiographs. These do not demonstrate any movements of the sacroiliac joints or plasticity of the hip bones. However, a symmetrical rotation of the hip joints conditions a retroversion of the pelvic girdle which explains the horizontalisation of the upper sacral plateau. This fixation of the block of the pelvic girdle is under muscular control, so that this mechanism can be improved by appropriate training.
Adult↗
Contribution of imaging to the understanding of the female pelvic fasciae.
According to the ultrasound and MRI findings, supported by planned dissections, the female perineum is organised around the musculofascial system converging towards the fibrous structure of the central perineal tendon (CPT). Behind the CPT the fascial layers form part of a fibrous assembly extending from the ventral surface of the sacrum to the anal complex, prolonging the direction of the sacral concavity downwards and forwards. On the other hand, in front of the CPT the fasciae fuse to form two aponeurotic bands circumscribing the urogenital fossa. The fascial system is reinforced cranially by the structures of the hypogastric sheath and the uterosacral ligaments. The weak point of the urogenital fossa is partly filled by the urethral-clitoridal-vulvar complex. The perineum so formed plays a cardinal role in stabilising the pelvic viscera. Stress is placed on the firmness of the posterior perineum, a key element in pelvic stability. The posterior perineum is often involved in pathological conditions and a good acquaintance with these structures is essential in defining therapeutic indications.
Adult↗
Cystic fibrosis arthritis. A report of five cases.
In a retrospective study of 206 patients with cystic fibrosis (CF), five cases of CF arthritis were recorded. This is a frequency of 2.5% and of 4.5% in patients aged over 10. Four patients had episodic arthritis, which was related to the course of pulmonary disease in two cases. In three patients, synovial fluid examination revealed minimal evidence of inflammation. In one of these three cases, synovial biopsy revealed a mild and non-specific synovitis. The fifth patient had chronic arthropathy and was positive for rheumatoid factor, but did not fulfil the criteria for rheumatoid arthritis. There were no radiographic abnormalities in any of these cases. CF arthritis is a rare syndrome of unknown pathogenesis.
Adolescent↗
[Correlations of CT and MRI imaging of the lateral pterygoid muscle].
On the basis of 15 CT scan and MRI studies of normal volunteers, the authors describe the features the lateral pterygoid muscle. A good correlation appears between CT and MR images which would be useful in the staging of tumors in this space, and in the pathophysiology of internal derangements of the temporomandibular joint (TMJ).
Humans↗
[Liddle syndrome (or pseudo-hyperaldosteronism). Long-term development and erythrocyte potassium flow study in 4 cases].
BACKGROUND: Liddle's syndrome (or pseudoprimary aldosteronism) is a rare hereditary disease; only 18 cases have been reported since 1963. Its cause remains unclear, but one of its features is increased cell membrane permeability to ions. PATIENTS AND METHODS: A diagnosis of Liddle's syndrome was made in 4 new cases, all female, two of them sisters (cases n0 3 and 4), at the ages of 2, 12, 5 and 4 years. The first manifestations were dehydratation with hypokalemia at 6 months (case n0 1), hypertension at 2 years (case n0 2), polydipsia with poor weight and height gain at 5 and 4 years of age (cases n0 3 and 4). At diagnosis, all the patients had severe hypertension, metabolic alkalosis, hypokalemia and hyperkaliuria, low plasma renin activity and serum aldosterone levels. Administration of antihypertensive agents was without effect, but the hypertension was reduced when triamterene and low-sodium diet were used. Hypercalciuria was observed in 2 cases and nephrocalcinosis in 2 (case n0 1 had both hypercalciuria and nephrocalcinosis). The 2 oldest patients (n0 3 and 4) developed progressive kidney failure, possibly due to reno-vascular disease secondary to hypertension. Patient n0 3 underwent kidney transplantation 18 years after the first symptoms of the disease. This resulted in the complete disappearance of her hypokalemia and hypertension. The red blood cell membrane permeability to K+ and Cl- was studied in all 4 cases before triamterene treatment. The passive permeability to K+ and (K+/Cl-) cotransport were both elevated. A second study, 3 years (cases n0 2 and 3) and 8 years (cases n0 1 and 4) later, of patients treated with triamterene showed low values for passive K+ permeability and (K+/Cl-)-cotransport. CONCLUSIONS: The 4 new cases of Liddle's syndrome had the classic features of the disease, except for hypercalciuria and nephrocalcinosis in 2 of them. The cell membrane permeability data are difficult to interpret. Hypokalemia and hypertension were immediately corrected after kidney transplantation in one case and remained so for 4 years, suggesting that this disease is tubular in origin.
Aldosterone↗
A study of the lateral pterygoid muscle: anatomic sections and CT appearances.
The authors have studied the relationship between anatomic and CT sections of the lateral pterygoid muscle in 39 anatomic specimens. Good superimposition of the images was found, which seems important in neoplastic invasion of the infratemporal fossa and which may lead to a pathogenic interpretation of the algo-dysfunctional syndrome of the masticatory apparatus.
Humans↗
The lymphatic drainage of the human ovary in vivo investigated by isotopic lymphography before and after the menopause.
The authors report 14 lymphoscintigraphies of the ovary, 8 before and 6 after the menopause. Injection of colloid labeled with technetium 99 m with elective lymphatic absorption was made into the mesovarium under laparoscopic control. Frontal and lateral images of the lymphatic drainage were made with a gamma camera 4-6 h after injection. Even in this short preliminary series, the premenopausal women showed major local and regional lymphatic circulation with drainage to the lumbo-aortic and pelvic nodes. After the menopause the lymphatic flow decreased and drainage was essentially by the aorto-lumbar nodes.
Adult↗
Lethal progeroid syndrome with osteolysis. Case report.
A particular progeroid syndrome with severe acro-osteolysis, cutaneous changes, failure to thrive, and early death is described in a young boy. Progeria and mandibulo-acral dysplasia are discussed, but early death is unusual in these two syndromes. This observation raises the question of a large spectrum including all of these syndromes.
Humans↗
[Arthritis in mucoviscidosis. 4 new cases and review of the literature].
Arthritis in mucoviscidosis has been described as aseptic arthritis with the picture of oligo or polyarticular intermittent rheumatism, independent of the pulmonary course of the disease, often accompanied by skin signs, sometimes in the form of vasculitis, and without radiological signs. Chronic forms with the presence of rheumatoid factor and/or radiological signs have also been described. The authors found 4 cases of arthritis (incidence 2%) in a retrospective study of 208 patients with mucoviscidosis. These included one case of typical intermittent rheumatism, one of chronic arthritis of the wrist with positive rheumatoid factor, one case associated with purpura, the course of which was linked to pulmonary secondary infections, and one case of polyarthritis with spinal pain which was difficult to classify. Arthritis in mucoviscidosis appears to be a clinically heterogeneous entity, the pathophysiology of which could involve various immune reactions, secondary to a chronic bacterial stimulus of bronchopulmonary origin.
Arthritis↗
Induction of labor with mifepristone (RU 486) in intrauterine fetal death.
In a double-blind controlled multicentric study involving 94 patients with an intrauterine fetal death, we investigated the efficacy and tolerance of mifepristone (RU 486), a steroid compound that antagonizes progesterone action at the receptor level. Success of treatment was defined as the occurrence of fetal expulsion within 72 hours after the first drug intake. Mifepristone treatment (600 mg per day for 2 days) was considered to be effective in 29 of 46 patients (63%). There were only eight successes in 48 patients (17.4%) in the placebo group (p = 0.001, chi 2 test). Tolerance was good in the mifepristone group. In the placebo group, disseminated intravascular coagulation occurred in one woman for whom the investigator waited several weeks for spontaneous expulsion. This large double-blind controlled study provides evidence that mifepristone is of interest in the management of intrauterine fetal death. It could provide a pharmacologic alternative to the use of prostaglandins in this indication.
Adult↗
Comparison of two oral rehydration solutions in eutrophic infants with moderate acute diarrhea: results of an interim analysis.
A randomized, multicenter clinical trial comparing two oral rehydration solutions (ORS) with different sugar content and total osmolality was carried out in France. Solution A had 168 mmol/L of sugar and a total osmolarity of 326 mosm/kg; solution D had 90 mmol/L of sugar and a total osmolarity of 240 mosm/kg. Weight gain, stool output, and biologic variables were analyzed. This interim analysis included 49 infants (27 in group A and 22 in group D). Patients in both groups gained weight without any significant difference between the two ORS. Between admission and day 4, the overall number of stools and the number of liquid stools decreased. Laboratory values were within the normal range on admission and remained unchanged. The weight increase during the first 24 hours and the reduced frequency of stools was similar in both groups.
Acute Disease↗