# Extraperitoneal Robot-Assisted Radical Prostatectomy Using Hinotori™ Surgical Robot System: Report of First Series of Seven Cases

## TL;DR

This paper reports on the first seven cases of robot-assisted prostate surgery using a new Japanese robot system, showing promising results.

## Contribution

The study presents the first clinical outcomes of extraperitoneal robot-assisted radical prostatectomy using the Hinotori™ surgical robot system in Japan.

## Key findings

- All seven patients successfully underwent extraperitoneal robot-assisted radical prostatectomy without conversion to open surgery or transperitoneal approach.
- Median operative time was 180 minutes with minimal blood loss and no major complications reported.
- The study suggests equivalent perioperative outcomes compared to transperitoneal approaches using this new system.

## Abstract

Objectives: The Hinotori™ surgical robot system (HSRS) (Medicaroid, Kobe, Japan), a newly launched domestic platform in Japan, has already been utilized in many robot-assisted surgeries. This study aimed to assess the perioperative outcomes of the first series of seven cases that underwent robot-assisted radical prostatectomy (RARP) with an extraperitoneal approach (EP) using HSRS.

Methods: A total of seven consecutive patients with localized prostate cancer who underwent RARP with EP using the HSRS between January and May 2025 at our institution were included in this study. Their comprehensive perioperative outcomes were retrospectively analyzed.

Results: The median age and the body mass index (BMI) of the patients were 69 years and 21.9 kg/m², respectively. RARP with EP could be completely performed on all patients without conversion to either a transperitoneal approach or open surgery. The median operative time, the time using the robotic system, the estimated blood loss, and the length of the indwelling urethral catheter were 180 min, 96 min, 100 mL, and seven days, respectively. No patient experienced major perioperative complications requiring invasive treatment or blood transfusion.

Conclusions: Despite being a small case series, this is the first report of the perioperative finding that RARP with EP using the HSRS is expected to provide equivalent perioperative outcomes compared to RARP with transperitoneal (TP).