Multifocal Skull Base Defects in the Setting of Spontaneous CSF Leak Secondary to Idiopathic Intracranial Hypertension

 

Introduction: The etiology of spontaneous cerebrospinal fluid (CSF) rhinorrhea and otorrhea continues to be unclear though evidence suggests that this may be a variant of idiopathic intracranial hypertension (IIH). The existence of multiple, concurrent skull base defects and associated synchronous CSF leaks in this population has never been explored.

Methods: A retrospective review of patients undergoing surgical management of spontaneous CSF rhinorrhea and otorrhea was conducted over a 10-year period. Analysis was performed to correlate recurrences and multiple skull base dehiscences with demographics, preoperative imaging, and perioperative variables.

Results: Forty-eight patients with spontaneous CSF leaks were included in the study. Thirty-four (70.8%) were rhinologic and the remainder were otologic in origin. The mean age was 52 years with 93% being female. Overall, 26 patients (54%) had at least two synchronous skull base dehiscences in the anterior or lateral skull base. Multiple encephaloceles were common as well with 18 patients (37.5%) having two or more encephaloceles on imaging; of these, we an average of 2.6 encephaloceles were visualized on imaging per patient. Leaks were most commonly located in the sphenoid (22.9%) and cribriform region (22.9%) and the tegmen (27.1%). The most common associated findings on MRI were empty sella (66.7%), arachnoid granulations (39.5%), and optic nerve changes (12.5%). Nine patients (18.7%) required reoperation, five patients (10.4%) were recurrences from the previous repair site, while four (8.3%) were de novo leaks from different locations in the skull base. Patients who leaked from a second location had an mean of 3.5 skull base dehiscences compared with 1.2 in controls that did not releak (p = 0.0090). Recurrent leaks also had a higher rate of dehiscence, 1.9 on average compared with the 1.2 in controls (p = 0.048). Acetazolamide was utilized in 28 cases (58%) postoperatively. Thirty-four (66.7%) patients had intraoperative lumbar drain placement. A multilayer closure was performed in 37 patients (77.1%) and trended toward a lower recurrence of CSF leaks (p = 0.095). Three patients underwent postoperative ventriculoperitoneal shunting and one patient underwent transverse sinus stenting. Neuroophthalmology evaluated 41 patients and 10.4% had papilledema.

Conclusion: Management of spontaneous CSF in patients with IIH is challenging and requires a multidisciplinary approach as multiple skull base defects and encephaloceles are a common and likely under-reported finding. The setting of IIH leads to a high recurrence of CSF rhinorrhea or otorrhea following surgical repair. The possibility of a second CSF leak in another, discrete location is less likely, however, still possible. Secondary bony defects may predict leak recurrence after repair, as well as synchronous leaks in separate locations in the skull base. Preoperative imaging must be thoroughly reviewed for secondary defects and surgical treatment of defects and perioperative management should be tailored to patients on a case-by-case basis.

Publication History

Article published online:
15 February 2022

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