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A positive result of re-operation in patients with recurrent symptoms after lumbar disc surgery is likely only if a new disc herniation is present. An improved ability to differentiate between recurrent disc herniation and scar tissue by contrast enhanced CT and MRI is suggested in earlier studies. In a prospective study 29 patients were selected for operation for suspected recurrent disc herniation. The inclusion of the patients was based on clinical symptoms and signs and myelography or non-enhanced CT. All patients were examined by CT and MRI both with and without intravenous contrast pre-operatively. The examinations were evaluated blind on a five point scale and statistical analysed by a regret function. Intravenous contrast improved the diagnostic power of both CT and MRI. MRI was superior to CT in both non-enhanced and enhanced examinations. MRI with intravenous contrast enhancement is proposed as the primary examination in patients with suspected recurrent disc herniation.

Study Design: A controlled prospective blinded study., Objectives: To compare the diagnostic power of myelography, computed tomography and magnetic resonance imaging in the diagnosis of low lumbar disc herniation., Methods: Eighty patients with monoradicular sciatica were examined by myelography, computed tomography, and magnetic resonance imaging, and all underwent subsequent surgery. The images were evaluated twice in a blinded fashion, and the diagnostic power of the modalities was expressed by a decision-analytic regret function., Results: In 57 patients (71%) a disc herniation at the expected level was disclosed at surgery. The largest amount of diagnostic information was gained from computed tomography, followed by magnetic resonance imaging and myelography. Both computed tomography and magnetic resonance imaging were significantly informative, whereas this was not the case for myelography., Conclusion: The results indicate that computed tomography or magnetic resonance imaging should be the first choice for imaging in patients with suspected lumbar disc herniation.

In reports of diagnostic methods in disorders of the spine focus is centred on diagnostic resolution, while psychological effects and patients' discomfort are often disregarded. To get a comprehensive picture of the appropriateness of a new technology the latter factors need to be explored and included in an assessment. In a prospective study, eight patients with signs of lumbar disc herniation underwent myelography, computed tomography and magnetic resonance imaging. A structured patient interview on attitudes to these technologies was carried out after all three examinations had been carried out. Myelography was most often reported painful and unpleasant among the three modalities. Discomfort due to magnetic resonance imaging stem from the narrow calibre of the machine and the noise. In computed tomography immobilization was the main reason for discomfort. Altogether most patients preferred computed tomography. In view of the fact that myelography must be considered as diagnostically inferior to the other two examinations, the reported discomfort from myelography indicates that computed tomography and magnetic resonance imaging should be the primary examinations for patients with lumbar disc herniation.

Thirteen patients with recurrent symptoms after lumbar discectomy were evaluated. All the patients were enrolled in the study on the basis of clinical symptoms and signs only. The patients were examined with MRI, CT, and myelography in order to compare a) the clinical findings with the imaging investigations, b) the predictive value of the different investigations, and c) the clinical and investigative results with the operative findings. All patients were operated upon according to the clinical findings, and the surgical results were used as the final diagnosis. In six patients a new disc herniation was detected. In the remaining cases surgery revealed either scar tissue or nothing to explain the recurrence of the symptoms. The three imaging modalities were analysed by receiver operating characteristic (ROC) curves. The areas under the ROC curves were 0.68 for MRI, 0.83 for CT, and 0.43 for myelography. The difference in areas between CT and myelography was significant (p less than 0.05). The results indicate that CT has the highest predictive value for demonstrating the recurrence of a lumbar disc herniation.