AimsWe report the cerebrospinal fluid opening pressure (CSF-OP) measurements obtained before and after venous sinus stenting (VSS) in 50 patients with idiopathic intracranial hypertension.MethodsThe CSF-OP was measured with a spinal tap 3 months before and 3 months after treatment. All data were prospectively collected and included patient demographics, weight (kg), body mass index (BMI), acetazolamide daily dosage (mg), procedural details, complications, venous sinus pressures (mm Hg), trans-stenotic pressure gradient (mm Hg), transverse sinus symmetry, and type of venous sinus stenosis.ResultsThe average pretreatment CSF-OP was 37 cm H₂O (range 25–77) and the average post-treatment CSF-OP was 20.2 cm H₂O (range 10–36), with an average reduction of 16.8 cm H₂O (P<0.01). The post-treatment CSF-OP was less than 25 cm H₂O in 40/50 patients. The average acetazolamide daily dose decreased from 950 mg to 300 mg at the time of 3-month follow-up (P<0.01). No patient required an increase in acetazolamide dose 3 months after VSS. The average weight before treatment was 95.4 kg with an average BMI of 35.41. There was an average increase in body weight of 1.1 kg at the 3-month follow-up with an average increase in BMI of 0.35 (P=0.03).ConclusionsWe provide evidence that there is a significant decrease in CSF-OP in patients with idiopathic intracranial hypertension 3 months after VSS, independent of acetazolamide usage or weight loss.