• Bloody tap • Dry tap • Cerebral herniation • Dysesthesia • Post-LP headache can occur due to leak of fluid into nearby tissues. • Infection introduced to subarachnoid space • Bleeding near puncture site or into epidural space • Puncture of the aorta or vena cava by accident, resulting in retroperitoneal hematoma • Brainstem herniation due to increased intracranial pressure • Minor neurologic symptoms such as radicular pain or numbness • Late onset of epidermoid tumors of the thecal sac • Back discomfort or pain in the site of lumbar puncture