Development of a Head-Mounted Holographic Needle Guidance System for Enhanced Ultrasound-Guided Neuraxial Anesthesia: System Development and Observational Evaluation

Abstract

Background: Neuraxial anesthesia is conventionally performed using a landmark-based technique. Preprocedural ultrasound is often used in challenging clinical scenarios to identify an ideal needle path. The procedure is then carried out by the operator recreating the ultrasound needle path from memory. We suggest that a needle guidance system using the Microsoft HoloLens mixed reality headset, which projects a hologram of the ideal needle path, can assist operators in replicating the correct needle angulation and result in fewer needle passes.

Objective: The objective of the study was to develop software for the mixed reality HoloLens headset, which could be used to augment the performance of neuraxial anesthesia, and establish its face validity in lumbar spine phantom models.

Methods: We developed an ultrasound transducer marker and software for the HoloLens, which registers the position and angulation of the ultrasound transducer during preprocedural scans. Once an image of a clear path from skin to the intrathecal space is acquired, a hologram of the ideal needle path is projected onto the user's visual field. The ultrasound probe is removed while the hologram remains in the correct spatial position to visualize the needle trajectory during the procedure as if conducting real-time ultrasound. User testing was performed using a lumbar spine phantom.

Results: Preliminary work demonstrates that novice (2 anesthesia residents) and experienced operators (5 attending anesthesiologists) can rapidly learn to use mixed reality holograms to perform neuraxial anesthesia on lumbar spine phantoms.

Conclusions: Our study shows promising results for performing neuraxial anesthesia in phantoms using the HoloLens. Although this may have wide-ranging implications for image-guided therapies, further study is required to quantify the accuracy and safety benefit of using holographic guidance.

Trial registration: ClinicalTrials.gov NCT04028284; https://ichgcp.net/clinical-trials-registry/NCT04028284.

Keywords: HoloLens; augmented reality; holograms; mixed reality; neuraxial anesthesia; virtual reality.

Conflict of interest statement

Conflicts of Interest: None declared.

©Jaya Tanwani, Fahad Alam, Clyde Matava, Stephen Choi, Paul McHardy, Oskar Singer, Geraldine Cheong, Julian Wiegelmann. Originally published in JMIR Formative Research (https://formative.jmir.org), 23.06.2022.

Figures

Figure 1

Optical tracking marker attached to a curvilinear probe to enable the HoloLens to detect transducer position.

Figure 2

This figure depicts a HoloLens user's view of aligning a Tuohy needle with a hologram representing an ideal needle path (white line) into an ultrasound phantom. The difference between the Tuohy needle and hologram positions is due to a recording artifact and is not perceived by the user.

Figure 3

The user performs a preprocedural ultrasound, allowing the headset to subsequently generate a spatially stable hologram. The inset shows the operator's mixed reality view displaying a holographic guidance graphic (orange line along the central axis of the ultrasound transducer) with the tracking marker attached to the ultrasound probe.

Figure 4

The user performs a neuraxial technique in standard sterile fashion. The inset shows the hologram projected into the user's visual field to aid replication of the ideal needle path as identified on ultrasound.