A multiparametric magnetic resonance imaging-based virtual reality surgical navigation tool for robotic-assisted radical prostatectomy

Abstract

Objective: Increased computational power and improved visualization hardware have generated more opportunities for virtual reality (VR) applications in healthcare. In this study, we test the feasibility of a VR-assisted surgical navigation system for robotic-assisted radical prostatectomy.

Material and methods: The prostate, all magnetic resonance imaging (MRI) visible tumors, and important anatomic structures like the neurovascular bundles, seminal vesicles, bladder, and rectum were contoured on a multiparametric MRI using an in-house segmentation software. Three-dimensional (3-D) VR models were rendered and evaluated in a side room of the operating room. While interacting with the VR platform, a real-time stereo video capture of the in situ prostate was obtained to render a second 3-D model. The MRI-based model was then overlaid on the real-time model by using an automated alignment algorithm.

Results: Ten patients were included in this study. All MRI-based VR models were examined by surgeons immediately prior to surgery and at important steps where visualization of the tumors and their proximity to surrounding anatomic structures were critical. This was mainly during the preparation of the prostatic pedicles, neurovascular plexus, the apex, and bladder neck. All participants found the system useful, especially for tumors with locally aggressive growth patterns. For small and centrally located tumors, the system was not considered beneficial due to lack of integration into the robotic console. A fully integrated system with real-time overlays within the robotic stereo viewer was found to be the ideal scenario.

Conclusion: We deployed a preliminary VR-assisted surgical navigation tool for robotic-assisted radical prostatectomies.

Figure 1

Manual segmentation of the prostate boundary and critical anatomic structures around the prostate on T2-weighted images using in-house segmentation software. All the following images were derived from the same experiment

Figure 2

Three-dimensional models based on manual segmentations. Both images represent the same model from two different perspectives. The tumor detected on MRI shows aggressive features with potential extraprostatic extension and invasion of the left neurovascular bundles MRI: magnetic resonance imaging

Figure 3

In situ view of the surgeon on the anterior aspect of the prostate during robotic-assisted radical prostatectomy. The stereo cameras of the da Vinci surgical system are used to record 3D stereo videos for rendering the 3D models of the in vivo prostate

Figure 4

Superimposed 3D model of in vivo prostate on the MRI-derived 3D model using an automatic alignment algorithm from three different perspectives VR: virtual reality; MRI: magnetic resonance imaging

Figure 5

Posterior aspect of the prostatectomy specimen. Based on the findings on MRI, we decided to perform a wide excision in the area of the tumor, since extraprostatic extension and potential infiltration of the neurovascular bundles were suspected

Figure 6

First successful transfer of the MRI and in vivo 3D models into the da Vinci stereo viewer in another patient. The surgeon could see both models and the in situ view simultaneously but was currently not able to use the da Vinci control systems to interact with the model