The distribution of mineral density in the cervical vertebral endplates.

Subsidence of various constructs into the vertebral body is a well-known complication in anterior fusion. Information on bone structure is needed, as a basis for improving these procedures. There are, however, no data available on the distribution of mineral density within vertebral endplates. In this study the regional distribution of mineralization within the cervical endplates with respect to endplate orientation (inferior and superior endplate) and level distribution (C3-C7) was examined by means of computed tomographic osteoabsorptiometry (CT-OAM). The distribution of mineralization in 80 cervical endplates of 8 spinal columns (4 male, 4 female, age range 38-62 years) in vertebrae C3-C7 was investigated by CT osteoabsorptiometry (CT-OAM). The subchondral mineralization distribution revealed considerable topographic differences within each endplate, whereby the areas of greatest density were found in the peripheral marginal zones with maxima in the posterolateral surface, whereas mineralization density was much lower in the central areas. The superior endplates showed an additional posteromedial maximum, whereas the inferior endplates showed an additional anterior mineralization maximum. Comparison of the distribution patters of inferior and superior endplates at different levels from C3 to C7 reveals a uniform increase of mineralization in the anterior portions from cranial to caudal. The mineralization distribution showed characteristic reproducible patterns. The maximal values occurred in the posterolateral parts, and can thus be considered a morphological substrate of high long-term loading. This can serve as a basis for improved prosthesis design and the anchorage point for various fusion techniques.

Serum S-100B concentration provides additional information fot the indication of computed tomography in patients after minor head injury: a prospective multicenter study.

Ninety percent of patients with minor head injury (MHI) who have cranial computed tomography (CCT) under the present clinical decision rules have normal scans. Serum concentrations of the astroglial protein S-100B were recently found to provide useful information, but these studies were too small to provide a statistically safe basis for changing the present rule. We have investigated whether S-100B concentrations in patients with MHI can provide additional information to improve indication of the need for an initial CCT scan. One thousand three hundred nine patients with MHI were enrolled in this prospective, multicenter study. All had a CCT scan to confirm diagnosis in accordance with the present clinical decision rules. S-100B was measured in serum samples obtained upon admission. Data were analyzed using contingency table and receiver operating characteristic curve and compared with those for healthy donors (n = 540) and with those for patients with moderate to severe head injury (n = 55). Of the 1309 patients studied, 93 exhibited trauma-relevant intracerebral lesions on the CCT scan (CCT+). With a cutoff limit of 0.10-microg/L S-100B (95th percentile of values in healthy volunteers), CCT+ patients were identified with a sensitivity level of 99% (95% confidence interval, 96% - 100%) and a specificity level of 30% (95% confidence interval, 29% - 31%). Adding the measurement of S-100B concentration to the clinical decision rules for a CCT scan in patients with MHI could allow a 30% reduction in scans. A prospective study of the clinical value of S-100B measurement in such patients is now under way.