[Diagnosis of extruded herniated disks].

In a patient with disk herniation it is often difficult to establish that the disk is free in the spinal canal. A retrospective medical record study comparing 65 cases of free herniated disk (FHD) confirmed upon surgery and 65 cases of disk protrusion (DP) demonstrated that FHD was more common in young male blue collar workers, especially those who worked in the sitting position. No clinical findings were diagnostic of FHD although the straight-leg raising test was positive at smaller angles than in disk protrusion. In this study, sensitivity and specificity of CT scan for the diagnosis of FHD were 75% and 80%, respectively. CT scan findings suggestive of FHD included a free disk fragment, found in 22.5% of cases, and an acute connecting angle. Saccoradiculography was more sensitive but less specific than CT scan in this study. In FDH, migration was common and ragged hernia contours were seen on the saccoradiculography images.