Evaluation of degenerative disease of the lumbar spine: MR/MR myelography versus conventional myelography/post-myelography CT

Background: To compare the use of magnetic resonance (MR)/MR myelography (MRM) with conventional myelography/post-myelography CT (convM) for detailed surgery planning in degenerative lumbar disease. Methods: Twenty-six patients with suspected complex lumbar degenerative disease underwent MRM in addition to convM as preoperative workup. Surgery was planned based on convM—as usual at our department. Post hoc, surgical planning was repeated planned again—now based on MRM. Furthermore, the MRM-based planning was performed by six independent neurosurgeons (three groups) of different degrees of specialisation. Results: In only 31 % of the patients, post hoc MRM-based planning resulted in the same surgical decision as originally performed, whereas in 69 % (n = 18) a different procedure was indicated. In patients with non-concurring convM- and MRM-based surgical plans, a less extended procedure was the result of MRM in six patients (23 %), a more extended one in five (19 %), and a related to side/level of decompression or nucleotomy different plan in six patients (23 %). In one patient (4 %), the MRM-based planning would have led to a completely different surgery compared to convM. Overall interobserver agreement on the MRM-based planning was substantial. Conclusions: Detailed planning of operative procedures for complex lumbar degenerative disease is highly dependent on the image modality used.