Outpatient lumbar radiculography: comparison of iopamidol and iohexol and a literature review.

A prospective study of 261 patients undergoing lumbar radiculography using 12 ml iopamidol (200 mgI/ml) was undertaken to determine whether the procedure could be performed safely on an outpatient basis. No statistically significant differences in the incidence and severity of side-effects were found between the 132 outpatients and 129 inpatient controls. Nine outpatients had to be kept in hospital at the end of a 4-h observation period and a further two outpatients were re-admitted to hospital because of severe side-effects. The current study was compared with a preceding study of identical design, already published, in which 200 patients underwent lumbar radiculography with 10 ml iohexol (240 mgI/ml). No statistically significant differences in the incidence and severity of side-effects between the two contrast media were evident up to 24 h after the examination. In the period between 24 h and 7 days, the incidence and severity of headache, nausea and dizziness were all significantly greater in the iopamidol group. Although outpatient radiculography can be performed safely with both contrast media, the higher incidence of delayed side-effects in the iopamidol patients prompts the authors to express a preference for iohexol for intrathecal use. The increased incidence of adverse reactions in female patients and the literature comparing iopamidol and iohexol for myelography are discussed.