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Background:. It is unclear whether the sacroiliac joint is vulnerable to adjacent segment disease. Clinical studies have suggested that many patients who have undergone lumbar arthrodesis will develop adjacent segment disease, which may contribute to sacroiliac joint degeneration. The purpose of the present study was to examine whether arthrodesis in the lumbar spine results in altered biomechanics at the sacroiliac joint that could contribute to adjacent segment disease within the joint. Methods:. With use of human cadavers in a biomechanical laboratory study, the effects of lower-lumbar arthrodesis and sacroiliac screws on the biomechanics of the sacroiliac joint were assessed. Human cadaveric pelves with lumbar spines were biomechanically tested in flexion-extension, rotation about the vertical axis, and compression along the vertical axis with single and double-leg support. Four conditions were compared: (1) intact, (2) L4-L5 arthrodesis, (3) L4-S1 arthrodesis, and (4) left sacroiliac screw. Construct vertical and horizontal motions at the anterior and posterior surfaces of the sacroiliac joint were measured. Results:. Significant measurable increases in motion of the sacroiliac joint related to arthrodesis of the lumbar spine occurred with flexion-extension loading (p < 0.05). No significant changes were observed for rotation about the vertical axis or compression along the vertical axis with single and double-leg support. Conclusions:. After 360°, 1 or 2-level lumbosacral spine arthrodesis, the sacroiliac joint showed a significant increase in rotational motion with flexion-extension loading. Increases in horizontal translation with axial rotation loading and vertical translation with axial compression loading were not significant. Clinical Relevance:. The risk of significant alteration of normal sacroiliac kinematics should be considered in all patients undergoing 360° lumbosacral arthrodesis.

BackgroundOdontoid process fractures are among the most common in elderly cervical spines. Their treatment often requires fixation, which may include use of implants anteriorly or posteriorly. Bone density can significantly affect the outcomes of these procedures. Currently, little is known about bone mineral density (BMD) distributions within cervical spine in elderly. This study documented BMD distribution across various anatomical regions of elderly cervical vertebrae.Methods and findingsTwenty-three human cadaveric C1-C5 spine segments (14 males and 9 female, 74±9.3 y.o.) were imaged via quantitative CT-scan. Using an established experimental protocol, the three-dimensional shapes of the vertebrae were reconstructed from CT images and partitioned in bone regions (4 regions for C1, 14 regions for C2 and 12 regions for C3-5). The BMD was calculated from the Hounsfield units via calibration phantom. For each vertebral level, effects of gender and anatomical bone region on BMD distribution were investigated via pertinent statistical tools. Data trends suggested that BMD was higher in female vertebrae when compared to male ones. In C1, the highest BMD was found in the posterior portion of the bone. In C2, BMD at the dens was the highest, followed by lamina and spinous process, and the posterior aspect of the vertebral body. In C3-5, lateral masses, lamina, and spinous processes were characterized by the largest values of BMD, followed by the posterior vertebral body.ConclusionsThe higher BMD values characterizing the posterior aspects of vertebrae suggest that, in the elderly, posterior surgical approaches may offer a better fixation quality.

Abstract. We treated 16 delayed unions and 57 nonunions of the tibial diaphysis with a below-the-knee functional brace. In 48 cases, bracing was preceded by fibular ostectomy, and ten patients had an additional bone graft. We were able to follow 67 patients, of whom six (8.7%) failed to respond to treatment. In patients with nonunion, bony healing occurred with a median of 4 months. There was no difference in the speed of healing according to the level of the defect. Shortening of the limb following ostectomy of the fibula had a mean of 3 mm in the delayed-union group and 5 mm in the nonunion group. Résumé. Nous avons traité 16 retards de consolidation et 57 pseudarthroses de la diaphyse tibiale avec une botte de type Sarmiento. Dans 48 cas l'appareillage a été précédé par une résection partielle du péroné et dix avait une greffe osseuse complémentaire. Nous avons suivi 67 malades dont six (8,7%) n'ont pas répondu au traitement. Chez les malades avec pseudarthroses la guérison osseuse s'est produite avec un temps médian de quatre mois. Il n'y avait aucune différence dans la vitesse de consolidation d'après le niveau du défaut osseux. Le raccourcissement du membre par la résection du péroné avait une moyenne de trois millimètres dans le groupe avec retard de consolidation et cinq millimètres dans le groupe avec pseudarthrose. [ABSTRACT FROM AUTHOR]