[The value of tomodensitometric studies in the diagnosis of the herniated lumbar disk. Apropos of 155 operated disks].

Correlation of radiological and pathological findings in 155 cases of operated herniated discs emphasizes the value of a CT scan in the diagnosis of these lesions. Imaging by the scanner is a safe and relatively low-cost procedure and its reliability is identical to that of other conventional exploratory methods. It should, therefore, become the initial examination conducted during investigation of sciatica thought to be of discal origin. Reliability of results has varied between 85 and 90 p. 100, according to the author, for this essentially simple and atraumatic method. Confirmation of the presence of a hernia requires the observance of clear signs: material of discal density amputating the spinal canal and spreading over the dural sheath. False negatives or positives usually occur in borderline cases or in previously operated patients. Differences in clinical and computed tomography findings, with undoubted absence of signs on the scan image, require further investigation by radiculography.