Introduction: The objective of this video is to show the technique of a novel MRI-USG fusion guided Cryotherapy of localized prostate cancer using Organ-based tracking technology and Nail-grid guidance.
Methods: The case was a 69 year-old man with history of open cholecystectomy and open hernia repair. His Eastern Cooperative Oncology Group (ECOG) Performance Status was 0 and he enjoyed an active daily living. His PSA was 11.9 ng/mL. Multi-parametric MRI prostate showed a 12x9 mm Prostate Imaging – Reporting and Data System (PI-RADS) 3 lesion at left anterior transitional zone in a 48ml prostate without extra-capsular extension. Transperineal MRI-Ultrasound fusion biopsy of the target lesion showed Gleason 3+3 PCa with maximal cancer core length of 13mm. 18 Systematic biopsy cores in other sectors were all benign. Focal cryotherapy using MRI-Ultrasound guidance was planned.
The patient received General anaesthesia and was placed in lithotomy position. The MRI images with the target lesion marked were displayed on the screen of the MRI-Ultrasound fusion machine. The 3D side-fire transrectal probe was inserted and stabilized with a probe holder. A Nail-grid, which was a mini-grid with larger holes equipped with green nails for needle insertion and release. MRI and Ultrasound fusion was performed with automatic 3D ultrasound scanning and organ-based tracking technology to provide accurate target localization. The expected ellipsoid treatment zones of cryotherapy ablations were planned on a dedicated software. Cryoprobes and thermoprobes were inserted at the planned path via the Nail-grid. Exact needle positions were confirmed with organ-based tracking in the fusion software. In the current case, 3 cryoprobes were used for treatment including at least 5mm margins, and the needles were released from the Nail-grid by turning the green nail around, before subsequent needles were inserted. This allowed MRI-Ultrasound fusion guided needle insertions using the flexible Nail-grid. Urethral warming was inserted through extra-stiff guidewire. The whole treatment including planning took 90 minutes. A Foley’s catheter was inserted at the end.
Results: Good treatment effect with overlapping iceballs was observed. The patient was discharged on the same day a few hours after operation, and the Foley’s catheter was removed on day 3. There was no complication. MRI prostate with contrast was repeated on day 7 and the hypoenhanced foci correlated well with the planned ablation zone.
Conclusions: Cryotherapy for prostate cancer can be precisely performed using the flexible Nailgrid, under the guidance of MRI-Ultrasound fusion Organ based tracking. This provides a fusion guided alternative to freehand cryoprobe insertion while preserving the flexibility of freehand needle insertions.