PROBLEM

REASON

Infection over the puncture site

May cause meningitis

Intracerebral mass lesion

May cause herniation

Increased intracranial pressure

May be indicative of a mass (see text); if there is no mass, puncture is usually safe

Before planned myelography (7-10 days)

May produce subdural collection of CSF, making studies impossible

Suspected spinal tumor

May produce deterioration; may make myelogram impossible

Coagulation deficit

May result in epidural or subdural hemorrhage, with resulting root and/or cord compression (rare complication)