Cerebrospinal Fluid Removal for Idiopathic Intracranial Hypertension: Less Cerebrospinal Fluid Is Best

Background: Although lumbar punctures (LPs) are used for diagnostic evaluation in idiopathic intracranial hypertension (IIH), they can also provide relief from IIH-associated headache. Conversely, low-pressure headache secondary to LP can be debilitating. Low-volume cerebrospinal fluid (CSF) removal to a 'high-normal' closing pressure (CP), approximately 18-20 cm H2O, may result in relief of IIH-associated headache with a lowered frequency of post-LP headache. Methods: We conducted a single-center retrospective analysis from 2011 to 2016 of patients who underwent fluoroscopic LPs aiming for high-normal CPs. Inclusion criteria were as follows: 1) pre-existing diagnosis of IIH, or opening pressure (OP) and clinical findings diagnostic for IIH; 2) height and weight recorded within 1 year; 3) documented LP data parameters; and 4) one week post-LP follow-up documenting whether headache was worse, unchanged, or better. Results: One hundred forty-six patients met the inclusion criteria. Mean age was 34.9 years ± 11.0, and mean body mass index was 39.2 kg/m ± 10.5. Mean volume removed was 9.7 mL ± 4.6. The mean CP was 17.9 cm H2O ±2.7. The mean pressure change (OP-CP) per volume removed was 1.50 cm H2O/mL ±0.6. Headache symptoms at follow-up were improved in 64% (80/125) of patients, worse in 26% (33/125), and unchanged in 10% (12/125). Eleven patients were headache-free, and 11 patients required hospital care for post-LP headache. Conclusions: Low-volume CSF removal to approximately 18 cm H2O resulted in relief of IIH-associated headache in most patients and a low incidence of post-LP headache. Although clinically variable, these data suggest that for every 1 mL of CSF removed, the CP decreases approximately 1.5 cm H2O.