© American Academy of Otolaryngology - Head and Neck Surgery Foundation 2014. Objective. Spontaneous cerebrospinal fluid (CSF) leaks typically present in patients with undiagnosed idiopathic intracranial hypertension (IIH) secondary to pressure erosion of the skull base. Despite elevated intracranial pressure (ICP) on lumbar puncture or ventriculostomy, patients with spontaneous CSF leaks rarely complain of visual disturbances. The objective of this study is to correlate the presence of preoperative papilledema with opening ICP in patients undergoing endoscopic repair of spontaneous CSF leaks.Study Design. Prospective study.Setting. Tertiary hospital.Methods. Prospective evaluation of patients with spontaneous CSF leaks was performed over a 1-year period (December 2012 to December 2013). Fundoscopic examination for papilledema was completed preoperatively and CSF pressure measured by lumbar puncture or ventriculostomy intraoperatively. Data regarding demographics, nature of presentation, and body mass index (BMI) were also recorded and compared to a control cohort of IIH patients with papilledema.Results. Sixteen patients (average age 52) were evaluated. Obesity was present in 94% of individuals (average BMI = 43, range, 27-65). Papilledema was absent preoperatively in all subjects. Opening pressures via lumbar puncture/ventriculostomy were 27.4 ± 7.7 cmH20. Following 6 hours of clamping, measurements significantly increased to 36 ± 9.6 cmH20 (P < .001). IIH controls (average age 33, average BMI = 36, range, 21-52) exhibited average ICP (36.2 ± 11.7) identical to postclamp measurements in the spontaneous CSF leak cohort.Conclusions. Subjects with spontaneous CSF leaks had postclamping average ICP identical to controls with IIH and papilledema. Such evidence suggests that a CSF leak in this patient population provides sufficient pressure diversion to avoid the development of papilledema.