Radical prostatectomy (RP) is an effective treatment leading to a high rate of oncological control. However, despite advances in robot-assisted RP, the genito-urinary function, especially erectile function and urinary continence, may be significantly impaired after surgery.
Our study aims to characterize and map the nerve fibers surrounding the prostate before and after surgery using diffusion tensor magnetic resonance imaging (DTI), a non-invasive magnetic resonance imaging (MRI) technique. This relatively new technology, combined with the 3D tractography software, will allow us to create a personalized 3D model of the periprostatic nerves. This virtual model will help us to assess the nerve bundles and how the surgery impacts their integrity. DTI and 3D reconstruction will be performed before and 6 months after surgery.
The pre-surgery 3D virtual model will be overlaid and mapped onto the intraoperative surgical view, providing the surgeon with a visual guide of the nerve fiber organization. At the post-surgery level, the 3D virtual model of the nerve bundles will be compared to the pre-surgery model. Post-treatment changes at 6 months may help assess nerve preservation and their relationship with erectile (dys)function.
The main questions the clinical study aims to answer are:
1. Post-treatment DTI-Tractography parameter changes at 6 months may help assess nerve recovery and their relationship with erectile (dys)function (PROMs - IIEF-5 score) 2. Post-treatment DTI-Tractography parameter changes at 6 months may help assess their relationship with urinary function 3. At the post-surgery level, the 3D virtual model of the nerve bundles will be compared to the pre-surgery 3D model. 4. The pre-surgery 3D virtual model will be overlaid and mapped onto the intraoperative surgical view, providing the surgeon with a visual guide of the nerve fiber organization (mean surgery time, surgeon feedback assessment, etc., will be evaluated.) Tumor location based on the 3D model will also be explored.
Histological confirmed diagnosis of prostate cancer (PCa) based on prostate biopsy
Multidisciplinary indication for radical prostatectomy, validated by the Urology Tumor Board
No prior treatment of prostate cancer
Capacity to provide informed consent
Unwillingness to participate.
Pre-existing impaired sexual function before surgery (IIEF5 Score of ≤21)
Diagnosis of neuropathy
Inability to comply with study procedure (e.g. due to language barriers, psychological disorders, dementia, anxiety/claustrophobia during pelvic MRI etc.) or medical contraindications to MRI
Single group
Prostate Tractography for Nerve-Sparing
Procedure/SurgeryTractography will be performed according to established best practices. To create the 3DVM, a high-performance workstation equipped with a high-end GPU will be used. ROI placement for nerve tractography and segmentation tasks will be performed semi-automatically using a previously trained nnU-Net pipeline. All inference will be strictly performed locally on this dedicated machine resulting in 4 segment masks (Prostate, Urethra, Index Lesion, Seminal Vesicles) that will be manually reviewed and corrected. The subsequent reconstructed Tractography bundles will be added to create the 3DTVM. The 3DTV model will be overlaid and mapped onto the intraoperative surgical view, providing the surgeon with a visual guide of the nerve fiber organizations (mean surgery time, surgeon feedback etc will be evaluated.)
Evaluation of erectile function at 6-month.
Imaging versus Patient-Reported Outcome Measure (PROM).
1. Evaluation of urinary function at 6 month follow-up.
Imaging versus Urinary Function Patient-Reported Outcome Measure (PROM).
Assessment of the feasibility of augmented reality using tractography-based 3D model.
To document the feasibility of augmented reality using a tractography model (operative time).
3. Concordance of pre- and postoperative Diffusion Tensor Imaging.
Evolution of nerve integrity after surgery
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Massimo Valerio
Lead sponsor
University Hospital, Geneva
Sponsor institution
University of Geneva, Switzerland
Collaborator
