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Abstract
Background and purpose We evaluated the inferior petrosal sinus (IPS) as a potential implantation site for a novel cerebrospinal fluid (CSF) shunt concept that can be placed across the dura by an endovascular approach to treat communicating hydrocephalus. This study outlines detailed measurements of the IPS, the adjacent cerebellopontine angle (CPA) cistern, and surrounding anatomy.
Materials and methods Gadolinium-enhanced brain T1-weighted MRI datasets of 36 randomly selected neurosurgical patients, aged 20–80 years, were analyzed using 3D multi-planar reconstruction to measure IPS diameter and length, CPA cistern depth, and proximity of the IPS to the vertebral and basilar arteries. Paired t-test, linear regression, and uni- and multi-variate analysis of variance were used to analyze measurements and evaluate dependence on age, gender and sidedness. Sidedness dependence was also evaluated on a per-patient basis of all measurements using matched-pair analysis. A p value of <0.05 was assumed for statistical significance.
Results Mean IPS diameter ranged from 2.27 mm to 3.31 mm at three axial levels with >90% larger than 1.46 mm. The depth of the CPA cistern adjacent to the IPS exhibited a mean depth of 3.86 mm to 7.39 mm between the dura and the brain stem at the same axial levels. There was no side-dependence except for a longer distance from IPS to basilar artery on left vs right (9.72 vs 7.28 mm, p<0.019). Linear regression showed distance from IPS to the brainstem to be statistically increased with age (p<0.0002) and greater in male patients (p<0.012), with little side variation (p=0.524).
Conclusion Our results demonstrate sufficient CSF CPA cisternal space adjacent to the IPS and support the feasibility of an endovascular catheter-delivered transdural implantable shunt. Such a device could serve to mimic the function of the arachnoid granulation by establishing a regulated path for CSF flow from the intracranial subarachnoid space to the venous system and provide a treatment for communicating hydrocephalus.
Disclosures C. Heilman: 2; C; CereVasc LLC. 4; C; CereVasc LLC. A. Malek: 2; C; CereVasc LLC. 3; C; Stryker Neurovasular, Microvention-Terumo. 4; C; CereVasc LLC.