Mixed Reality Displays Feasibility in Robot-Assisted Partial Nephrectomy

Using Mixed Reality (MIXREAL), a combination of virtual reality (VR) and augmented reality (AR), in robot-assisted partial nephrectomy (RAPN) displayed feasibility and safety in treating patients with solid or cystic renal masses requiring partial nephrectomy, according to findings from the randomized REALITATEM trial published in the International Brazilian Journal of Urology.

In patients treated with MIXREAL RAPN (n = 20), the mean ischemia time was 14.6 minutes vs 18.4 minutes with control RAPN (n = 25; P = .045). A total of 5 clamping cases occurred in the former group and none in the latter, with off-clamp procedures occurring in 40% vs 28% of the respective arms (P = .527).

Furthermore, the mean estimated blood loss (EBL) in the investigational and control arms was 264.6 mL vs 138.0 mL (P = .085), and 1 patient in the control group underwent red blood cell transfusion (P = .556). Hemostatic agents were administered in 95% and 88% of the respective groups (P = .085). More patients in the MIXREAL arm underwent enucleation (40%) vs in the control group (20%; P = .288).

Regarding conversion, subsequent radical nephrectomy (RN) was performed in 2 patients in the control group, and no cases were converted to open surgery. In these cases, the tumors were hilar, and the main renal vein was drained directly from the tumor. Additionally, the pathology results and the functional variables were similar between groups.

“In view of all the already proven and potential benefits for the use of MIXREAL, it is expected that its use can increase [partial nephrectomy] indications and improve the nephron sparing surgery success rate,” Dorival Manrique Duarte Jr., a surgeon in the Department of Urology of the Hospital Moinhos de Ventos in Porto Alegre, Rio Grande de Sul, Brazil, wrote in the publication with study coinvestigators. “Three-dimensional models can be accessed by the surgeon for a detailed study of the case before surgery or may be used intraoperatively as both consultation and overlay in real time.”

Patients selected for enrollment were randomly assigned 1:1 to the MIXREAL RAPN or control partial nephrectomy. Patients received a CT angiography within 1 month of surgery, where images were exported to Digital Imaging and Communications in Medicine (DICOM) and rendered in the Brainlab Elements® software to obtain the VR. All patients enrolled underwent transperitoneal RAPN, which was performed at Moinhos de Vento Hospital, from August 2022 to January 2024.

Most patients in the investigational or control arms were male (65.0% vs 72.0%), White (85.0% vs 100%), and overweight (28.6 kg/m² vs 26.8 kg/m²). The mean age in the respective groups was 60.2 years (SD, 12.0) and 60.4 years (SD, 15.4). Moreover, the most common previous abdominal surgery was nodule (85.0% vs 84.0%), renal lesion laterality was left (50.0% vs 56.0%), R.E.N.A.L score was between 7 and 9 (45.0% vs 48.0%), and American Society of Anesthesiologists score was II (85.0% vs 80.0%).

The study assessed tumor and patient intra-operative vessel clamping, ischemia time, EBL, hemostatic agents, and excision techniques. Additionally, post-operative measures, such as renal function, pathology results, complication rate, and length of hospital stay, were examined.

The study found no significant difference in complication rate between the 2 treatment strategies, with most being Clavien-Dindo grade 1. A grade 2 complimentary clinical treatment was needed by 2 patients in the MIXREAL group: a pancreatitis case and an acute renal injury case. Additionally, 1 patient in each arm experienced a grade 3 event, with 1 in the MIXREAL arm experiencing late urinary fistula and 1 in the control arm experiencing a spleen injury during surgery. There was additionally a non-significant difference in hospital stay: 3.3 days vs 2.7 days in the respective arms (P = .261).

Reference

Duarte DM, Brum PW, Berger M, Kowalski A, Neto BS, Berger AK. Robot-assisted Partial Nephrectomy with and without Mixed Reality - REALITATEM study. Int Braz J Urol. 2026;52(2):e20250463. doi:10.1590/S1677-5538.IBJU.2025.0463