Efficacy of Z-shaped supine position in Robot-Assisted Radical Prostatectomy: Study Protocol for a Randomized Controlled Trial

Background Prostate cancer is the second most common cancer among men worldwide and is frequently managed with robot-assisted radical prostatectomy (RARP). Standard patient positioning during RARP, specifically the lithotomy and steep Trendelenburg positions with a head-down angle of 25°–45°, can lead to complications such as peripheral nerve injury, elevated intraocular pressure (IOP), dizziness, nausea, and vomiting. This study introduces an alternative "Z-shaped supine position," aimed at reducing postoperative position-related complications and improving patient comfort. Methods This single-center, randomized controlled trial will recruit 78 patients scheduled for RARP. Participants will be randomly assigned to either the standard RARP position group or the Z-shaped supine position group. The Z-shaped supine position involves 10°–15° hip flexion, 5°–10° knee flexion, and 20°–30° leg abduction, combined with a 20°–25° Trendelenburg tilt. This position is supported by an integrated shoulder and neck brace. Outcomes include the incidence of peripheral nerve injuries (primary outcome), intraoperative IOP, skin contact pressure, deep vein thrombosis, postoperative pain, and pressure injury. Assessments will be conducted preoperatively, intraoperatively, and postoperatively at multiple time points. Statistical analyses will include an intention-to-treat (ITT) approach and comparisons between the two groups. Discussion This study aims to validate the Z-shaped supine position as a safer alternative to standard positioning during RARP, with a focus on reducing perioperative complications while maintaining both functional and surgical outcomes. Trial registration Chinese Clinical Trial Registry ChiCTR2300072954. Registered on 28 June, 2023.