Needle diameter in outpatient myelography: rates of adverse effects and current practice trends

Telephone calls were made to 1251 consecutive patients one day following ou tpatient myelography. Data were available on 518 patients punctured with 22 -gauge (g) (large-diameter) and 465 with 25-g (small-diameter) spinal needl es. We surveyed 48 academic and private practice groups regarding needle di ameter use in myelography; data were obtained from 34 private practice and 14 academic radiology departments. Patients reported adverse effects includ ing mild and severe headache, back pain and nausea. The percentage of total adverse effects was significantly greater in the 22-g than in the 25-g nee dle group. The percentage of patients with headache was higher in the 22-g than in the 25-g group, but this difference was not statistically significa nt. Only 19% of private practice groups and 17% of academic centers use 25- g needles; the remainder use 20-g or 22-g needles.