Biomechanical comparison of isokinetic lifting and free lifting when applied to chronic low back pain rehabilitation.

The study compares free and isokinetic lifting using a multivariate statistical analysis. Each of the 13 male subjects performed three free lifts and three isokinetic lifts using a CYBEX LIFTASK. The measurement variables were obtained from a 3D video system, two force plates and two strain-gauge transducers. Coupling of fuzzy space-time windowing and multiple correspondence analysis was used to show the links between the variables and the differences between the experimental situations. Isokinetic lifting had almost no points in common with free-lifting, but there was a similar range of extension for the different joints. Most free-lifting strategies could not be used in isokinetic lifting, as constraints between the subject and his environment were different. The main drawback of the isokinetic lifting was due to the necessity for individuals to reach the machine speed, yielding high transient efforts. The maximum vertical effort at the L5/S1 joint was about 1600, 1500 and 1400N for low, medium and high speed, whereas it was lower than 1300N, irrespective of the load, during free lifting. In the context of chronic low back pain rehabilitation, movement strategies used in free lifting could not be relearnt using an isokinetic machine. A better understanding of the common points and differences between isokinetic movement and free movement could help rehabilitation physicians to plan rehabilitation programmes, taking advantage of each kind of movement.

Descriptive multidimensional statistical methods for analysing signals in a multifactorial biomedical database.

A methodology is presented to analyse multidimensional signals from several recording periods resulting from an experimental study on human or other living systems. The methodology is divided into two stages: intra-period analysis and inter-period analysis. The purpose of the first stage is to highlight general trends in multidimensional signal changes and the more informative components of the signals. The purpose of the second stage is to assess the influence of environmental or individual difference factors on a given signal component that appears to be discriminant in the first stage. To take into account the multivariable state of the system and the multi-observational aspect, a multidimensional descriptive statistical approach is used. The methods are correspondence analysis and hierarchical clustering. They are illustrated through an occupational medicine application from a study of sedentary posture.

Hidden corrosion detection in aircraft aluminum structures using laser ultrasonics and wavelet transform signal analysis.

Preliminary results of hidden corrosion detection in aircraft aluminum structures using a noncontact laser based ultrasonic technique are presented. A short laser pulse focused to a line spot is used as a broadband source of ultrasonic guided waves in an aluminum 2024 sample cut from an aircraft structure and prepared with artificially corroded circular areas on its back surface. The out of plane surface displacements produced by the propagating ultrasonic waves were detected with a heterodyne Mach-Zehnder interferometer. Time-frequency analysis of the signals using a continuous wavelet transform allowed the identification of the generated Lamb modes by comparison with the calculated dispersion curves. The presence of back surface corrosion was detected by noting the loss of the S(1) mode near its cutoff frequency. This method is applicable to fast scanning inspection techniques and it is particularly suited for early corrosion detection.

[Value of biopsy of accessory salivary glands for the diagnosis of amyloidosis]. / Intérêt de la biopsie de glandes salivaires accessoires pour le diagnostic d'amylose.

There are few reports of amyloidosis diagnosed by deliberate biopsy of accessory salivary glands. Usually, a biopsy performed for dry mouth syndrome reveals an unsuspected amyloidosis. We report the case of 2 patients with lambda-type light chain monoclonal gammapathy complicated by generalized amyloidosis and in whom biopsy of the accessory salivary glands showed signs of amyloidosis. In the first patient accessory salivary gland biopsy was performed because these glands were enlarged, and the monoclonal dysglobulinaemia was subsequently diagnosed by serum immunoelectrophoresis. In the second patient with nephrotic syndrome, renal biopsy could not be carried out owing to the presence of a renal malformation; amyloidosis was confirmed by periumbilical fat aspiration, and a systematic biopsy of accessory salivary glands also showed evidence of amyloidosis. Biopsy of accessory salivary glands seems to be a particularly simple and safe method to detect generalized amyloidosis in patients with chronic inflammatory disease or monoclonal dysglobulinaemia.

Spinal surgery procedure discretization.

In the last decades, scientists developed analytic models of spinal surgery to assess surgical choices and instrumentation parameters. They noted the difficulty to represent the boundary conditions on their deterministic models and recognize the lack of knowledge in surgical procedures. This paper presents a formalization technique applied to spinal surgery to improve the formulation of biomechanical models. This technique consisted into two steps: knowledge extraction and knowledge representation. The protocol was established with an expert surgeon using Colorado2 instrumentation. Surgeon's knowledge acquisition has permitted to define eleven detailed independent data cards for the different steps of surgery like hook or screw insertion, rod installation, etc... The behaviour of the concerned elements on its neighbouring entity were specified using three matrices. The link between surgery and modelling becomes easier and permits to better define the boundary conditions on each entity during the simulation.

Numerical predictions and experiments for optimizing hidden corrosion detection in aircraft structures using Lamb modes.

To increase the sensitivity of Lamb waves to hidden corrosion in aircraft structures, a preliminary step is to understand the phenomena governing this interaction. A hybrid model combining a finite element approach and a modal decomposition method is used to investigate the interaction of Lamb modes with corrosion pits. The finite element mesh is used to describe the region surrounding the corrosion pits while the modal decomposition method permits to determine the waves reflected and transmitted by the damaged area. Simulations make easier the interpretation of some parts of the measured waveform corresponding to superposition of waves diffracted by the corroded area. Numerical results permit to extract significant information from the transmitted waveform and thus to optimize the signal processing for the detection of corrosion at an early stage. Now, we are able to detect corrosion pits down to 80-mum depth distributed randomly on a square centimeter of an aluminum plate. Moreover, thickness variations present on aircraft structures can be discriminated from a slightly corroded area. Finally, using this experimental setup, aircraft structures have been tested.

A combined finite element and modal decomposition method to study the interaction of Lamb modes with micro-defects.

This paper presents a combined finite element and modal decomposition method to study the interaction of Lamb waves with damaged area. The finite element mesh is used to describe the region around the defects. On the contrary to other hybrid models already developed, the interaction between Lamb waves and defects is computed in the temporal domain. Then, the modal decomposition method permits to determine the wave reflected and transmitted by the damaged area. Modal analysis allows also identifying the mode conversions induced by the defects. These numerical results agree with previous finite element results concerning the interaction of Lamb modes with a notch. Experiments, carried out with gauged defects on an aluminum plate, are also compared to numerical predictions to validate the simulation. Compared to classical techniques of simulation, this new method allows us to investigate the interaction of Lamb modes generated at high frequency-thickness product with micro-defects as corrosion pitting.

[Surgery of scoliosis. Decision aid by three-dimensional imaging (3D)]. / Chirurgie de la scoliose: Aide à la décision par l'imagerie en trois dimensions (3D).

Scoliosis is a spatial deformations of the spine not reducible to a plan. Usually perception of this phenomena is made from frontal and lateral radiographies and needs a mental process to construct a 3D form. The proposed aid-system consists, firstly, to construct a 3D model from digitalised characteristic points on radiographies, and to visualize this model from any point of view, even the above view. Secondly, corrective bending posture radiographies are used to estimate kinematic spine variables and then to simulate optimal orthopedic correction. Methods and materials are adaptable for other osteo-articular systems.

Surgical treatment of trigonocephaly. Experience with 30 cases.

Trigonocephaly results from premature closure of the metopic suture. We report our experiences with 30 patients who underwent surgical treatment. In our opinion, this type of craniosynostosis also involves sphenoid bone dysplasia. For this reason, our surgical procedure includes turning the orbital ridge away from the midline, frontal vault remodeling, and a wide ostectomy of the pterional bone.

Magnitude and phase photoacoustic spectra of chrysotile asbestos, a powdered sample.

Magnitude and phase photoacoustic spectra of a powdered sample made of chrysotile asbestos have been recorded with a low resolution grating spectrometer at ~16 Hz. A good reproduction of the true absorption spectra is obtained from the recording of the phase variation. The optical, thermal, and acoustical effects occurring within this heterogeneous sample are discussed, and a qualitative explanation of the observations is given.

[Arthrotomy for the permanent displacement of the temporomandibular meniscus. A coagulation-retraction technic of the posterior meniscal frenum]. / Arthrotomie pour déplacement permanent du ménisque temporo-mandibulaire. Technique de la coagulation-rétraction du frein méniscal postérieur.

An original technique for surgical treatment by arthrotomy for permanent closed lock of the temporo-mandibular joint is described. This technique uses the temporo-meniscal compartment approach. The superior belly of the posterior meniscal attachment is dissected and retracted by a diathermy coagulation. Advantages of this technique are compared to the usual techniques of meniscopexy and meniscorrhaphy using a suture. The indications are proposed.

Did Mozart have a chronic extradural haematoma?

When Mozart died at the age of 36, was he suffering from the belated complications of a calcified extradural haematoma? This theory took shape during the identification process of the skull owned by the Mozarteum, when the print of calcified extradural haematoma was discovered on the left inner temporoparietal calvarial surface of the skull. This print looks like a rosette, with three distinct concentric areas. The first outer area is striated, the second middle one is granular and scattered with bony deposits, the third central one is marked with vascular grooves.

[Contrast arthrography of the temporomandibular joint]. / L'arthrographie opaque de l'articulation temporo-mandibulaire.

Seventy-four temporomandibular arthrographic examinations, mostly involving paracentesis of the menisco-condylar compartment, provided the means for visualizing normal and pathologic aspects of both reducible and non-reducible meniscal dislocations, and of perforations. Findings included distension of the bilaminar zone and adhesions. Post modeling condyloplasty status was noted. At present, arthrography seems to be the most reliable test, as well as being the easiest to perform and the least expensive one for visualizing menisco-condylar abnormalities.

[Arthrography of the temporomandibular joint]. / L'arthrographie de l'articulation temporo-mandibulaire (ATM).

In 1989, opaque contrast arthrography of temporomandibular joint is still seldom used. A brief historical review of the procedure is presented here, and the technique of puncturing the menisco-condylar and menisco-temporal compartments is discussed. The value of injecting opaque contrast material into the lower compartment and carrying out kinetic and tomographic studies as well as bilateral examinations is stressed. Normal aspects are described with their variants, as well as pathological ones (reducible and non-reducible luxations, perforations, distension of the bilaminar zone, adhesions, etc.). Both the place of arthrography in relation to other investigations (TDM, IRM) and its indications for visualization of menisco-condylar problems are discussed.

[Treatment of osteo-dural injuries of the anterior segment of the skull base through the trans-lesion approach. Apropos of 25 cases surgically treated by a dual neurosurgical and maxillofacial team]. / Traitement des brèches ostéo-durales de l'étage antérieur de la base du crâne par voie trans-lésionnelle. A propos de 25 cas opérés en double équipe neurochirurgicale et maxillo-faciale.

The authors describe a technique of mobilisation of the frontal sinus using the fractures of anterior and posterior walls. The translesional approach is adapted to cranio-facial borders surgery of traumatisms. It's a skull base approach which minimizes the cerebral retraction and enables or perfect viewing of the top of the ethmoid. The advantages, drawbacks and indications are discussed about 25 cases.

Evaluation of desmopressin for dental extractions in patients with hemostatic disorders.

We evaluated the effectiveness of desmopressin to control bleeding of patients with coagulation defects during dental surgery. Thirty-five patients, mainly with moderate and mild hemophilia and Willebrand disease, were undergoing dental extractions (over 80 extractions in total). Bleeding was successfully prevented in 28 patients with the use of a combined treatment incorporating IV desmopressin, an antifibrinolytic agent (tranexamic acid), and local methods (surgical glue and compression techniques). Seven patients had a bleeding episode after dental extraction, which was controlled in two cases by repeated injection of desmopressin and in another two by local methods; Factor VIII substitutive treatment was needed in only three patients. Desmopressin offers an alternative to blood products to control bleeding risk in patients with moderate and mild coagulation defects. Our experience tends to specify the mode of administration of both desmopressin and the associated treatments. Our findings suggest that desmopressin can be used in conjunction with other treatments to prevent bleeding in patients with coagulation defects who undergo dental surgery. This work highlights the concept of multifactorial medical care of these patients in which desmopressin plays a major role.

[Adenoid cystic carcinoma of the salivary glands. Apropos of 52 cases]. / Carcinomes adénoïdes kystiques des glandes salivaires. A propos de 52 observations.

52 cases of adenoid cystic carcinoma of the salivary glands are reported according to the age of the patient, to the localisation near an osseous structure or in soft tissues, to the histologic grade, to the therapeutic management, viz the surgical or radiotherapy treatment, correlated to the survival. It is worthy to notice that the localisations to the palate have a better prognosis than the localisations in soft tissues. Cribriform histologic grade in the same way have a better involvement than basaloid grade, but worse than tubular grade. Effectiveness of radiotherapy does not appear clearly in our study, unlike the observations of some authors.