3D characterization of pores in the cortical bone of human femur in the elderly at different locations as determined by synchrotron micro-computed tomography images.

UNLABELLED: Diaphysis, inferior, and lateral superior regions of the femoral neck are subjected to diverse mechanical loads. Using micro-CT based on synchrotron radiation, three-dimensional morphology and connectivity of the pore network are location dependent, underlying different remodeling mechanisms. INTRODUCTION: The three-dimensional (3D) morphology and connectivity of the pore network at various locations in human femurs subjected to diverse mechanical loads were assessed using micro-CT based on synchrotron radiation. METHODS: The cortex from 20 human femurs (mean age, 78.3 ± 12.4 years) was taken from the diaphysis (D), the inferior (IN), and the lateral superior (LS) regions of the femoral neck. The voxel size of the 3D reconstructed image was 7.5 µm. Cortical thickness and pore volume/tissue volume (Po.V/TV), pore diameter (Po.Dm) and spacing (Po.Sp) were determined. The pore surface/pore volume ratio (Po.S/Po.V), the number of pores (Po.N), the degrees of anisotropy (DA), and the connectivity density (ConnD), the degree of mineralization (DMB) were also determined. RESULTS: The characteristics of the pore network in femoral cortical bone were found to be location dependent. There was greater porosity, Po.Dm, and Po.N, and more large (180-270 µm), extra-large (270-360 µm) and giant pores (>360 µm) in the LS compared to the IN and D. The difference in porosity in between the periosteal and endosteal layers was mostly due to an increase of Po.Dm rather than Po.N. There was a lower DMB of bone in the LS, which is consistent with a higher remodeling rate. CONCLUSION: The results provide evidence for large variations in the structure of the internal pore network in cortical bone. These variations could involve different underlying remodeling mechanisms.

[Value of the use of surgical endoscopy in chest surgery in children]. / Intérêt de l'utilisation d'une "endoscopie chirurgicale" en chirurgie thoracique chez l'enfant.

The authors emphasize the various possibilities of exploration of chest with the mediastinoscope, in a 11 patients series, aiming and reducing surgical parietal approach in infancy, while preserving the feasibility of the procedure. In the thoracic level: beyond the mediastinal approach by the transcervical pathway (mediastinoscopy), the principal application is the pleural cavity access (pleuroscopy) which was performed in seven 3 to 12 years old children. Pleuroscopy was realised through a small intercostal access permitting biopsy with a good visibility (pulmonary biopsy: 4 cases; lateral mediastinal tumor: 2 cases). A cloisonned pyopneumothorax drainage was performed once easily managed. Mediastinoscopy was used likewise in 3 cases of transcervical thymectomy (myasthenia gravis or thymic hyperplasia), permitting effective visual field to control quality of exeresis. This "surgical endoscopy" procedure offers so food indications in Pediatric Surgery, more especially as not any complication was observed.