Incidence of adverse effects following metrizamide myelography in nonambulatory and ambulatory patients.

A study was done to determine whether cerebrospinal fluid loss through a lumbar puncture tear or metrizamide contact with central nervous system tissue is the more important contributor to postmyelographic headache. To do this, the influence of postmyelographic positioning was recorded in 43 ambulatory and 43 nonambulatory (confined to bed for 24 hours after the procedure) patients. The incidence of headache was 10.5% in the ambulatory group and 43.6% in the nonambulatory group (p less than 0.01). There were no significant differences between the two groups with respect to leg and back pain or nausea and vomiting. It is concluded that irritation of the central nervous system by metrizamide is more important as a causative factor of postmyelographic headache than is cerebrospinal fluid leakage. Following metrizamide myelography, patients can be encouraged to be ambulatory without any increase in the incidence of adverse effects.