Background Approximately 125,000 new cases of occlusive hydrocephalus are seen every year leading to 40,000 operations every year in the US. Occlusive hydrocephalus has been treated tradition ally by surgically placed ventriculo-lumbar or ventriculo-peritoneal shunts. Complications include CSF overdrainage, proximal and distal shunt obstruction as well as infections necessitating 48% reoperations in children within 3 years. Approximately 62,500 shunts are replaced every year and 50% will have to be replaced within 5 years. More recently transcranial rigid and flexible neuroendoscopes are used for 3rd ventriculostomy with immediate effect. About 25% of patients are treated by surgical 3rd ventriculostomy using neuroendoscopes.

Objective Based on our previous successful catheter navigation in pediatric population for gene delivery to the skull base,^{1 2} we propose a minimally invasive translumbar endocisternal approach to a 3rd ventriculostomy (EVT).

Methods 3D printed cranio-spinal CSF models generated from age-adjusted human data were constructed. Multimodal imaging guidance (MIG) was created and included MRI and ConeBeam CT combined with real-time fluoroscopy. Subsequently access systems compatible with steerable catheter-based systems were developed and refined using the 3D models to perform a translumbar ETV using MIG followed by an assessment of various systems in 10 sheep, including survival studies and in human cadavers.

Results MIG required several hours of training to get used to steer systems successfully for an EVT. Sheep models although challenged by access due the small CSF compartment and the location of the spinal cord, helped to tailor access and steerable systems for a safe ETV prior to implemented the procedure into a human cadaver. Intraoperative cisternography and ventriculography as well as histology specimen showed no damage to the spinal cord, brain and vasculature, provided the right tools are used. MIG and training using 3D CSF models are critical for safe and successful ETV in occlusive hydrocephalus.

Conclusion Preliminary preclinical studies show that endocisternal 3rd ventriculostomy is feasible but will require multimodality imaging and appropriately constructed tools for a safe procedure and adequate training. The trans-lumbar CSF navigation with direct access to both spinal and intracranial spaces could address not only a occlusive hydrocephalus but disorders such as arachnoid cysts, aquaeductal stenosis and serve for brain/spine biopsies, drug and gene delivery as well as placement of microsensors and implants for neuromodulation using a simple translumbar CSF access.

References

1. Taghian T, Marosfoi MG, Puri AS, et al. A safe and reliable technique for CNS delivery of AAV vectors in the cisterna magna. Mol Ther 2020;28:411-421.

2. Flotte TR, Cataltepe O, Puri A, et al. AAV gene therapy for Tay-Sachs disease. Nat Med 2022;28:251-259.

Disclosures A. Wakhloo: 1; C; Philips. 2; C; Philips. 4; C; Deinde Medical. 6; C; Philips. J. Chueh: 1; C; Philips. B. Hallacoglu: 5; C; Philips. D. Dresser: 5; C; Deinde Medical. M. Litzenberg: 5; C; Deinde Medical. N. Laxminarain: 5; C; Deinde Medical.