Quantitative discomanometry and acute disk injuries: an experimental model.

Abstract

Quantitative discomanometry is a study of intradiscal pressure changes during quantitative injection. The purpose of this study was to determine if correlations exist between discomanometric parameters and disk injuries. Sixteen three-vertebrae porcine spine segments, with two intervening disks, were subjected to standardized high-speed trauma. The injuries were documented by a radiographic injury score (RIS), using pre- and posttrauma lateral radiographs. An anatomic injury score (AIS) also was obtained, based on an anatomic dissection and mid-sagittal plane cuts of the frozen specimen. Before the cutting, each of the disks was subjected to quantitative discomanometry, providing pressure/volume curves. Significant negative correlations were found between the RIS and the maximum pressure sustained (R = -0.60, p < 0.001), and pressure/volume slope (R = -0.60, p < 0.001). Similar relationships were found between the AIS and the maximum pressure (R = -0.71, p < 0.001), and pressure/volume slope (R = -0.63, p < 0.001). This study suggests that quantitative discomanometry can be used to quantify disk injuries. Because the intradiscal pressurization mimics the physiology with weight bearing, its use as a measure of integrity of the end-plate-annulus-end-plate enclosure might be justified.