Fifty-six patients with low back pain and sciatica following radiological investigation were found to have abnormalities at multiple levels, more than one of which could be responsible for the clinical picture or at a single level, which correlated poorly with the clinical findings. Thirty-four patients had a diagnostic peri-neural root infiltration to clarify whether surgery would be appropriate. Evaluation of the technique was by reduction in analgesia. Eighteen patients have had surgery, 14 with a successful, two a moderate and two a poor outcome. Four patients have been denied and two are awaiting an operation. Ten patients referred for a diagnostic procedure deferred surgery in favour of a therapeutic course. Of 22 patients referred directly for a therapeutic course, 15 had a successful, three a moderate and four a poor result. CT-directed peri-radicular root infiltration is a useful adjunct in the management of low back pain and sciatica.