Ultrasound Guided Lumbar Puncture and Remote Guidance for Potential In-Flight Evaluation of VIIP/SANS

INTRODUCTION: Changes of visual function/neuro-opthalmic structures during spaceflight have been described as visual impairment and intracranial pressure syndrome (VIIP)/spaceflight-associated neuro-ocular syndrome (SANS). Although theories are suggested, the mechanism is unknown. Only indirect measurements of intracranial pressure (ICP) have been performed in spaceflight. Direct determination of in-flight ICP is crucial to understanding VIIP. Current "gold standard" is lumbar puncture (LP). The only direct evaluation has occurred with postflight LP. In-flight measurements would allow correlation of opening pressures/possible contributing factors. The only imaging modality on the International Space Station (ISS) is ultrasound. With appropriate methodology, remotely guided ultrasound-guided lumbar puncture (USGLP) may allow safe performance in flight. Therefore, we sought to develop a novel ultrasound approach for definitive placement of an LP needle, and to show this can be achieved with remote guidance by those without training.METHODS: Literature review and round-table discussions with multiple medical fields was performed. Volunteers were scanned with ultrasound for optimizing technique. A cadaver was used to perform this technique by a radiologist, then taught to volunteers not experienced in image guided procedures, and finally was repeated multiple times by volunteers with simulated remote guidance.RESULTS: Optimal visualization was in the fetal and seated exaggerated kyphotic [corrected] positions. Technical success was achieved by the radiologist in all attempts and achieved in 9 of 11 attempts by the trainees.DISCUSSION: Given ultrasound experience at NASA and the ability to educate non-image-guided trained personnel, these could make this technique feasible and aid in direct in-flight measurements to further research VIIP.Lerner DJ, Chima RS, Patel K, Parmet AJ.