Disc degeneration can be graded reliably on routine T2-weighted magnetic resonance images using the grading system and algorithm presented in this investigation.

Although neovascularization is a specific sign for pain, it does not indicate an unfavorable outcome. Conversely, tendon inhomogeneity seems to be associated with an unfavorable outcome.

Debate continues on the effect of disc degeneration and aging on disc volume and shape. So far, no quantitative in vivo MRI data is available on the factors influencing disc volume and shape. The objective of this MRI study was to quantitatively investigate changes in disc height, volume, and shape as a result of aging and/or degeneration omitting pathologic (i.e., painful) disc alterations. Seventy asymptomatic volunteers (20-78 years) were investigated with sagittal T1-and T2-weighted MR-images encompassing the whole lumbar spine. Disc height was determined by the Dabbs method and the Farfan index. Disc volume was calculated by the Cavalieri method. For the disc shape the ''disc convexity index'' was calculated by the ratio of central disc height and mean anterior/posterior disc height. Disc height, disc volume, and the disc convexity index measurements were corrected for disc level and the individuals age, weight, height, and sex in a multilevel regression analysis. Multilevel regression analysis showed that disc volume was negatively influenced by disc degeneration ( p < 0.001) and positively correlated with body height ( p < 0.001) and age ( p < 0.01). Mean disc height and the disc convexity index were negatively influenced by disc degeneration but not by gender, weight, and height. Disc height was positively correlated with age ( p < 0.01). From the results of this study, it can be concluded that disc degeneration generally results in a decrease of disc height and volume as well as a less convex disc shape. In the absence of disc degeneration, however, age tends to result in an inverse relationship on disc height, volume, and shape. ß

No abstract

The question of whether the impairment of the endosteal blood supply, which is induced by nailing with reaming of the medullary cavity, increases the risk of a postoperative infection cannot be conclusively answered by studying existing literature. The aim of this study was to investigate the effect of medullary reaming on the occurrence of local infection based on an infection model in the rabbit tibia (n = 44). An infection rate of 50% was found after unreamed nailing, as opposed to an infection rate of 64% after medullary reaming. The number of bacteria observed after reaming was significantly higher than after nail insertion without previous reaming. The differing susceptibilities to infection as observed in this model are statistically significant (p < or = 0.05).