CT-guided nerve root block and ablation.

Abstract

We report our experience in performing 52 CT-guided peripheral nerve root blocks and 27 CT-guided nerve root ablations. The nerve root block procedures were performed as diagnostic tests to determine the clinical significance of equivocal herniated disk or foraminal stenosis (n = 33) and before nerve root ablations (n = 19). To evaluate the clinical significance of these nerve root blocks, we performed 52 procedures at the vertebral level where a herniated disk or foraminal stenosis had been identified on CT or MR images. In 51 of 52 cases, the procedures were successful in anesthetizing the intended nerve root, which allowed us to determine whether that particular nerve root was the source of pain. By relieving or not relieving pain, the results of the diagnostic nerve root blocks helped determine whether a protrusion or foraminal stenosis was clinically significant. The nerve root ablations were done exclusively for treatment of pain in patients with malignant disease. Significant relief of pain was obtained in 17 (63%) of 27 patients. The thoracic nerve ablations were the most successful (9/10 or 90%) because the correct thoracic nerve innervation to the offending lesion could be identified. The lumbosacral nerve ablation procedures were the least successful (6/14 or 43%) because the innervation of the pelvic neoplasms was complex, arising from multiple lumbosacral nerves that often were bilateral. Equivocal foraminal stenosis and disk protrusion are common findings on CT and MR imaging, and CT-guided nerve block procedures can help determine which of these findings are clinically significant. CT-guided nerve root ablations have limited efficacy but can help control pain in patients with a malignant disease, especially when the pain is in the distribution of a thoracic nerve dermatome.