No abstract

Ninety-five patients with acute low-back and radicular pain underwent magnetic resonance (MR) imaging and either plain computed tomography (CT) (n = 32) or CT myelography (n = 63) for diagnosis of herniated nucleus pulposus-caused nerve compression (HNPNC). Patients were followed up for at least 6-12 months. Fifty-six patients underwent surgery, and 39 received conservative treatment. Receiver operating characteristic (ROC) analysis was performed on correlation of results of blinded image reading with "true" diagnoses determined by an expert panel [corrected]. Results in subgroup analysis for ROC curve areas were MR, 0.84, versus plain CT, 0.86; MR, 0.81, versus CT myelography, 0.83; and MR, 0.82, versus findings with both CT techniques, 0.85. Results indicate no statistically significant difference in diagnostic accuracy of HNPNC among the three modalities. Thus, factors of cost, radiation dose, and invasiveness influence selection of modality. On the basis of accuracy findings, the authors suggest that MR should replace CT myelography because of the invasiveness of myelography but that MR should not replace plain CT because plain CT is equally accurate and much less costly.

Three significantly different lateral approaches to the cervical subarachnoid space (anterior, midplane, and posterior needle positions) have been previously described for cordotomy and myelography. Experimental lateral C1-2 punctures were performed by each of these three methods in anatomic specimens, cadaver models with reconstituted cerebrospinal fluid pressures, a patient with cerebral death, and to a limited degree in patients undergoing routine cervical myelography. In the cervical region the dura is pushed ahead of the needle, forming a "tent" over the needle tip during C1-2 puncture; the needle projects several millimeters into the spinal canal before penetrating the dura, regardless of the method of entry or needle diameter. The extent of this tenting phenomenon and its relationship to the spinal cord are significantly affected by the needle diameter and position. A posterior technique for lateral C1-2 puncture is described.

An acute traumatic epidural hematoma extending from the odontoid process to the dorsum sella is described. The mechanism for the formation of an extradural hematoma in this unusual location seems to be related to age and a severe hyperflexion injury.