Lumbar Puncture in the 21st Century: An Imaging-Based Primer to Determine Procedural Safety.

Lumbar puncture (LP) is a crucial procedure in the diagnosis and management of multiple neurologic diseases, and the procedure can be safely performed in most patients. However, dangerous complications may rarely occur, including herniation and death. There remains a paucity of high-quality data identifying patients at increased risk of life-threatening complications from LP, even in the post-neuroimaging era. Therefore, we performed a comprehensive review of the literature to summarize the known physiologic changes and associated complications after LP, especially in the presence of central nervous system mass lesions or altered cerebrospinal fluid dynamics. Based on this, we propose an imaging-based primer to guide clinicians in making decisions about candidacy for LP. Imaging findings that contraindicate LP include the presence of supratentorial mass lesions with preexisting herniation or significant midline shift, medium to large posterior fossa masses, posterior fossa malformation, globally elevated intracranial pressure with mass effect or generalized edema, severe brain sag, and obstructive hydrocephalus. We integrate these imaging features with prior LP clinical guidelines for a concise flowchart to aid in identification of LP contraindications.